MULT‘ - EMPEDANCE LOADiNG 0F UNEAR ANTENNAS FOR IMPROVED. TRANSMlTTlNG’ AND RECEIVING CHARACTERISTICS T hesi's for the Degree»? Ph..D.‘ ‘ MlCHiGAN STATE UNNERSITYV ; _ PHMP LYLE .FANSONF' . 1972 Laws. 'Y 5 Michigan tare UHIVCISIL')’ This is to certify that the thesis entitled MULTI-IMPBDANCB LOADING OP LINEAR ANTENNAS FOR IMPROVED TRANSMITTING AND RECEIVING CHARACTBRI QTICS presented by Philip Lvle Panson has been accepted towards fulfillment of the requirements for _P_h..D.__degree in W11 Engr. 7 {xi/A72» [/évx. Major professor / Date '72—“30; /972. 0-7639 5' Bl ‘ IV "0A8 & SUNS” n, 800K BINDERY WC. . Lsa=nav smoms fl ‘3 ”mum: mum ‘1. '-i ABSTRACT MULTI-IMPEDANCE LOADING OF LINEAR ANTENNAS FOR IMPROVED TRANSMITTING AND RECEIVING CHARACTERISTICS By Philip Lyle Fanson This thesis presents a method by which the trans- mitting and receiving characteristics of a linear antenna may be improved or modified by the use of multi—loading. The idea of modifying the antenna characteristics by impedance loading is not new. In recent years many researchers in the antenna area have studied the technique both theoretically and experimentally. Most works, however, are restricted to single or double loading. A few experimental studies dealing with multi—loading lack theoretical explanation. In this thesis, the general case of multi-loaded transmitting and receiving linear antennas is investigated based on a systematic and rigorous approach. The main findings of this thesis are as follows. For a transmitting antenna if (1) the antenna current is specified at M + N points, (2) the radiation field is specified in M + N directions, (3) the input impedance is specified at M + N different frequencies, or (A) any Philip Lyle Fanson linear combinations of case (1), (2), and (3), then M + N complex impedances can be found at M + N specified locations. For the case of pure reactive loading with M + N reactances, only (M + N)/2 values of the antenna characteristics can be specified. An interesting case of loadings which lead to the resonance or instability of a transmitting antenna is discussed. For a receiving antenna, M + N complex impedances can again be found at M + N specified locations if (1) the antenna current is specified at M + N points, (2) the scattered field is specified in M + N directions, or (3) the combination of cases (1) and (2) and if the central load is specified. The case of loading which will cause resonance or instability in a receiving antenna is also studied. MULTI-IMPEDANCE LOADING OF LINEAR ANTENNAS FOR IMPROVED TRANSMITTING AND RECEIVING CHARACTERISTICS By Philip Lyle Fanson A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Electrical Engineering 1972 ACKNOWLEDGMENTS The author wishes to express his appreciation to his major professor, Dr. K. M. Chen, for his guidance and support through the course of this work. He also wishes to thank the other members of his guidance committee, Drs. D. P. Nyquist, J. S. Frame, J. Asmussen, and B. Ho, for their time and help. The author wishes to specially thank Dr. Frame for his help in developing the minimization method for the non-linear equations. Finally, the author wishes to thank his wife, Elaine and children, for their support during this work. 11 TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES I. II. III. INTRODUCTION MATHEMATICAL FORMULATION OF A MULTI—LOADED RADIATING ANTENNA . . . . . . . 2.1 2. 2 Matrix Formulation Resonance Loading . . 2. 2.1 Admittance Constraint 2. 2. 2 Resonance Loading . 2. 2. 3 Resonant Loading - Unstable Conditions . . . . 2.2.3.1 Numerator Of Vl And V2 Zero . . 2.2.3.2 Coefficient Of V2 Zero .2.“ Voltage Constraint . . . . 2.2.“.1 Field Pattern Constraint 2.2.A.2 Current Constraint 2.2.4.3 Input Admittance - Frequency Constraint .2.5 Combined Admittance And Voltage Constraint Reactive Loading - 2.2.5.1 Current Constraint 2.2.5.2 Reactive Loading - Frequency - Current CURRENT DISTRIBUTION ON A LOADED RADIATING ANTENNA . . . . . . 3.1 Current Distribution On A Short 3 3.1 3.1 Antenna . . . . 1.1 Vector Potential of Symmetric Dipole .2 Difference Equation .3 Current Distribution iii 11 11 12 14 l6 17 17 2O 21 23 23 27 31 31 31 3A 35 IV. VI. VII. 1.“ Evaluation Of Constants .1. 5 Special Cases . . . . . . . . 3.2 urrent Distribution On A Long Antenna 2.1 Current On An Infinitely Long Antenna . . .2.2 Reflected Current At The End Of A Semi— Infinite Antenna .2.3 Current On An Asymmetrical Finite Antenna . . RADIATION PATTERNS OF SHORT AND LONG ANTENNAS . . . . . . . . . . . . . “.1 Radiation Pattern Of A Short Antenna. A.2 Radiation Pattern Of A Long Antenna NUMERICAL SOLUTION OF THE SIMULTANEOUS NON— LINEAR EQUATIONS AND NUMERICAL EXAMPLES . . . . . . . . . . . .1 Method Of Minimization . . . . . .2 Example Of Minimization Method - N = 2 . . . . . . . . . . . Modified Newton's Method Additional Techniques . . . . Numerical Examples . . . . . 5.5.1 Admittance Constraint . . . . Field Pattern Constraint . . . Current Constraint Input Admittance - Frequency Constraint . . . 5.5.5 Reactive Loading - Current Constraint . . . . . . 5.5.6 Reactive Loading — Frequency And Current Constraint . 5.5.7 Resonance Loading . U‘IUTU'I mm U'IJr-‘LJO U1U1U1 UTUTU'I: tuck) MATHEMATICAL FORMULATION OF A MULTI-LOADED RECEIVING ANTENNA . . . . . . . . . . 6.1 Matrix Formulation 6. 2 Constraint Equations . 6'.2. 1 Load Impedance Constraint . 6. 2. 2 Scattered Field Constraint . . 6. 2. 3 Current Constraint . . . 6. 2. A Current And Scattered Field Constraint . . . . . . . CURRENT DISTRIBUTION AND SCATTERED FIELD PATTERN OF AN UNLOADED ROD 7.1 Vector Potential or An Unloaded Rod ,7.2 Current Distribution On A Short Rod iv 39 M2 AZ A6 A7 61 61 63 6A 66 68 68 71 76 83 85 85 92 92 96 97 100 102 107 107 109 7.3 Scattered Field Of A Short Unloaded Rod . . . . 111 7.“ Current Distribution On A Load Rod. . 112 7.“'.l Current On An Infinitely Long Rod . . . . . 112 7.“.2 Reflection At The End Of A Semi- Infinite Rod . . . . . . 113 7.“.3 Current On A Finite Rod . . . 11“ 7.5 Scattered Field Of A Long Rod . . . . 115 VIII. ADDITIONAL NUMERICAL EXAMPLES . . . . . . 118 8.1 Resonance Loading . . . . . . . . 118 8.2 Scattered Field Constraint . . . . . 120 8.3 Current Constraint . . . . . . . 123 8.“ Current And Scattered Field Constraint . . . . . . . . . . . . . 123 IX. CONCLUSIONS . . . . . . . . . . . . . . . 131 BIBLIOGRAPHY APPENDIX 5. 1 LIST OF TABLES Solutions To Input Impedance—Frequency Constraint (Four Frequency Case) vi 77 Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure 5.3 5.“ 5.5 5.6 5.7 At Four LIST OF FIGURES Multi-Loaded Transmitting Antenna . . Voltage Equivalent Of A Multi- Loaded Transmitting Antenna . Asymmetrically Driven Antenna . . . . Symmetrically Driven Antenna . . . . . . The c Plane And The Contour CO . . . Current Distribution For A Transmitting Antenna Which Was Loaded With 2“OQ at d1 = 3A/8 (a = 0.00635A) . . . . . . . . . . . Current Distributions For A Transmitting Antenna Which Was Loaded With -J 363 Ohms At d = 0.792 Meter (f = 600 MHz And a = 0.00318) . . . . . . . . . . . . Field Pattern For A Transmitting Antenna Loaded At Nine Points (PT(O) = Sin(3e))o o o o o o o o o o o o 0 Field Pattern For A Transmitting Antenna Loaded At Four Points (PT(O) = sin(2e)). Current Antenna At Four Distribution For A Transmitting On Which The Current Was Specified Points (Traveling Wave). . . . . Current Antenna Distribution For A Transmitting On Which The Current Was Specified Points (Decaying Wave) . . . . . . Input Impedance vs. Frequency For A Transmitting Antenna (Four Frequency Case - 509 " SOlUtion I)o o o o o o o o o o o o 0 vii 32 “5 69 7O 72 73 7“ 79 U1 .10 .11 .12 .13 .1“ .15 .16 Input Impedance vs. Frequency For A Transmitting Antenna (Four Frequency Case - 509 "' 80111131011 II) o o o o o o o o o o o o o o 0 Input Impedance vs. Frequency For A Transmitting Antenna (Two Frequency Case - Frequency Dependent) . . . . . . . . . . . . . . . . . Input Impedance vs. Frequency For A Transmitting Antenna (Two Frequency Case - Frequency Independent) . . . . . . . . . . . . . . . . . . Current Distribution For A Transmitting Antenna On Which The Current Was Specified At Two Points (Reactive Loading) . . . . . . . Input Impedance vs. Frequency For A Transmitting Antenna (Two Frequency - Reactive Loading - Frequency Independent) . . . . . . . . . . . . . Input Impedance vs. Frequency For A Transmitting Antenna (Two Frequency - Reactive Loading - Frequency Dependent) . . . . . . . . . . . . Loading Impedance vs. Frequency For A Trans- mitting Antenna To Maintain A Rbsonance Instability (Finite Voltage) . . . . . . . . . . Loading Impedance vs. Frequency For A Trans— mitting Antenna To Maintain A Resonance Instability (Zero Coefficient) . . . . . . . . Graphical Solution Of Resonance Loading Condition For A Transmitting Antenna Multi-Loaded Receiving Antenna . . Voltage Equivalent Of A Multi-Loaded Receiving Antenna . . . . . . . . . Unloaded Rod . . . . . . . . . . . . . Load Impedance vs. Frequency For A Receiving Antenna To Maintain The Resonance Instability Graphical Solution Of Resonance Loading Condition For A Receiving Antenna . Field Pattern For A Receiving Antenna Specified At Three Points (PT(O) = sin 20) . . . . . . viii 80 81 82 8“ 86 87 88 89 91 93 9“ 108 119 122 8.“ 8.5 8.6 8.7 8.8 8.9 Current Distribution For A Receiving Antenna For Which The Central Load And Current Were Specified At Four Frequencies (f = 300 MHz) . . . . . . Current Distribution For A Receiving Antenna For Which The Central Load And Current Were Specified At Four Frequencies (f = 320 MHz). . . . . . . . . . . Current Distribution For A Receiving Antenna For Which The Central Load And Current Were Specified At Four Frequencies (f = 3“O MHz) . . . . . Current Distribution For A Receiving Antenna For Which The Central Load And Current Were Specified At Four Frequencies (f = 360 MHz) . . . . . . . Scattered Fields For A Receiving Antenna For Which The Current And Radiation Pattern Are Specified At Two Frequencies: (a) f = 300 MHz e- (b) f = “00 MHz Current Distributions For A Receiving Antenna For Which The Current And Radiation Pattern Are Specified At Two Frequencies: (a) f = 300 MHz And (b) f = “00 MHz ix 12“ 125 126 127 128 129 CHAPTER I INTRODUCTION This study will present a method by which the transmitting and receiving characteristics of a linear antenna may be improved or modified by the use of multi- loading. The idea of modifying the antenna characteristics by impedance loading is not new. In recent years many researchers in the antenna area have studied this technique both the theoretically and experimentally. However, most works are restricted to single or double loading. A few experimental studies dealing with multi—loading lack theoretical explanation. In this study, the general case of multi-loaded transmitting and receiving linear antennas is investigated based on a systematic and rigorous approach. In Chapter 2, the basic antenna characteristics are GXpressed in matrix form as functions of loading impedances and antenna parameters. In addition the desired antenna characteristics are expressed in the form of constraint eQuations. These constraint equations are combined with matrix equations to determine the solutions. In Chapters 3 and “, antenna currents and field patterns for both short and long linear antennas are derived. Chapter 5 iS 1 2 devoted to numerical techniques and examples of transmitting antennas. Chapter 6 is concerned with the development of the matrix and constraint equations for a multi-loaded receiving antenna. In Chapter 7, the current and scattered field of an unloaded receiving antenna, both short and long, are presented. Finally, Chapter 8 presents additional numerical examples of a multi-loaded receiving antenna. The main findings of this study are as follows. For a transmitting antenna if (1) the antenna current is specified at M + N points, (2) its radiation field is specified in M + N directions, (3) the input impedance is specified at M + N different frequencies, or (“) any linear combination of cases (1), (2), and (3), then M + N complex impedances can be found at M + N specified loca— tions. For the case of pure reactive loading with M + N reactances, only (M + N)/2 values of the antenna characteristics can be specified. An interesting case of loadings which will lead to the resonance or instability of the antenna is discussed. For a receiving antenna, M + N complex impedances can again be found at M + N specified locations if (1) the antenna current is specified at M + N points, (2) the scattered field is specified in M + N directions, or (3) the combination of cases (1) and (2) and if the central load is specified. The case of loading which will cause resonance or instability in a receiving antenna is also studied. CHAPTER II MATHEMATICAL FORMULATION OF A MULTI-LOADED RADIATING ANTENNA In this chapter the basic equations which mathematical- ly describe a multi-loaded radiating antenna will be derived. The functional relationships between the driving voltage, the loading impedances, and the antenna dimensions will be developed. Finally constraint equations will be derived based on the required antenna performance. 2.1. Matrix Formulation The problem of a multi-loaded antenna can be treated by considering each load as a voltage driver at an arbi- trary driving point and applying the superposition principle. Consider a center-driven antenna of length 2h, and radius a, having N + M arbitrary loads along its axis, as shown in Figure 2.1. If each load is replaced by the voltage induced across it, the problem becomes equivalent to the antenna in Figure 2.2. This second antenna can easily be broken into M + N asymmetrically driven antennas as shown in Figure 2.3. Since the solution for the current on an asymmetrically driven antenna is a function of frequency, w; radius, a; half length, h; and position of the driver, dj’ the current at 3 Figure 2.1 Multi-Loaded Transmitting Antenna V-(M-l) -M +1 [GIG-6.919] l9] IGIG) + I +—— Q I A .3 l—J a. l 3 + I + d l dN _ N-l + d1 + I I + + I + I (9‘6! Figure 2.2 Voltage Equivalent Of A Multi—Loaded Transmitting Antenna d 4 d3 6 A 2a -> ‘— d i Figure 2.3 Asymmetrically Driven Antenna 7 any point can be expressed as IJ(z) = ij(m,a,h,dj,z) 3: -M to N. (2.1) To find the voltage Vj’ at each load on the original antenna, the relation VJ = ZJI tf two inductors, L1 and L2, and two capacitors, Cl and C2. Iget V1 and V2 be the voltage across L1 and L2 respectively sand VO be the driving voltage. The admittance at the l ciriving point, YO would be given by Y; = 1/(Jw(Ll + L2) — 3(0l + C2)/C1C2a). Vihen w is adjusted so that the system is in resonance, the V : cienominator of the expression for YO goes to zero and Y0 zapproaches infinity. In addition since V0, L1 and L2 are alssumed finite, the current in the system, and thus V and 1 'V2, must also approach infinity. Thus by analogy the antenna can be thought to be a series resonant circuit with distributed components. 2.2.3. Resonant Loading - Unstable Conditions In Section 2.2.2 indeterminate conditions were deferred, these will now be discussed. 2.2.3.1 Numerator Of V1 and V2 Zero If the determinant in the numerator of Equation 2.6 is also zero, then Vl becomes indeterminate. TO determine the value of V1 a form of 1'Rospita1's rule 1 will be used. Solving the numerator of V1 for Y2 gives 15 I Y _ fds f.d d 2R ’ 21 f 02/ 01, (2.11a) £3ince the denominator of Equation 2.6 must also be zero, ' ' _ ds ds Y2RY1R ' f21f12' (2’12) ' [Ising Equations 2.11a and 2.12 and solving for Y1R gives ' _ ds d d Y1R - f12f01/f02 . (2.11b) ' IIt should be noted that for N = 2,Y1R also causes Equation 23.7 to become indeterminate. For N > 2, however, this is riot true, up to N - 2 of the voltages can be indeterminate Inithout all of them being indeterminate. To find V1 and V2 let Y2 = Y2R + e (2.13a) Y1 = Y1R + as (2.13b) undere e approaches zero and a is the tangent of the complex euugle from which the point is approached. Substituting Ekguations 2.13a-b into Equations 2.6 and 2.7 and neglecting the second order 5 terms gives l d ' Vl — -VOfOl/(Y1R + aY2R) (2.1“) d ' ' V v2 — -VOfO2/(Y1R + aY2R). (2.15) Since a can be any number in the complex plane, the values of both V1 and V2 are dependent on how the indeterminate point is approached. This is typical of an instability point. 16 2.2.3.2 Coefficient Of V2 Zero In Section 2.2.2, the second indeter- rninate condition was that if the coefficient of V in 2 IEquation 2.10 equals zero, Equation 2.10 became indeter- rninate. Setting that coefficient to zero and solving for V Y1 gives ' _ fds f.ds 10 ' f2150/1423 ' (2°16) Y ligain since the denominator of Equation 2.6 is zero, from ' IEquations 2.12 and 2.16 Y2C will be ' _ ds f.ds Y2C — f12f20/f10 (2.17) Again letting ! l 8 Y2 _ Y2C + e (2.1 a) 1 l 8 Y1 — ch + a. (2.1 b) 811d neglecting second order 5 terms ds (2.19) V2 ds f.ds f.ds f20 ' d ds d __ = __ F _ . VE)(f20f21f10/Yl) Y' (Y' + Y' )LY10f02 f12f01] 0 20“ 1c Substituting Equation 2.19 into Equation 2.10 gives fd fds fds (2°20) = d _ .21119 20 d ' d8 d Yo f00 v' ' ' v ' [f02ch ‘ f12f013‘ lC ch(Y20“ + ch) Since a is again completely arbitrary, this is another in- stability point where the input impedance is indeterminate and loading voltages approach infinity. If, however, F is l7 a.symmetric matrix (long antenna case), it can be shown that v v 1 = Y and Y = Y and YlR 10 2c 2R _ d d ' YO — foo - fOl/YlR . (2.21) IIn addition, V1 and V2 become indeterminate as in the first czase instead of infinite. 2.2.4 Voltage Constraint The voltage can be specified in several ways. ESince it is explicitly related to both the current distri- taution and the field pattern of an antenna, these types of Jeelationships will now be developed. 2.2.U.l Field Pattern Constraint For an asymmetrically driven antenna, as Efluown in Figure 2.3, the field pattern can be shown to have tl1e following form, PJ(O) = ng(m,a,h,dJ,o). 1H1erefore by superposition, the field pattern of a multi- loaded antenna is given by N 1311(0) = i§_MVig(w,a,h,di’e) Which reduces for the symmetric antenna to N PTS(@) = V0g(w,a,h,0,0) + iglvigs(w:aahadi:e) where 18 gs(w,a,h,di,e) = g(w,a’h,di,e) + g(w’a’h,di,e)o E3y specifying the field pattern at N + M angles in the ggeneral case and at N angles for the symmetric antenna, Dd + N or N complex equations are obtained. Thus the unknown \Ioltages can be I N k = N g M for N Z M and fij = f(m,a,h,di,zj) where X results as i I = V X sum ng T(zj) o J J is a specified value. To keep the resulting non-linear equations as simple as possible, Equations 2.29 and 2.3 are combined as follows: E G v 1 = -M, -(M-l),---, k + 1 C -D V 1 ¢ 0 (2.30) 26 where r’d d d d fll+JBl fkl f11 fk+21 ' E = d d. d d. i flk fkk+JBk fik fk+2k ' d d d d + Lfli ‘ ' ' fki f11 JB1 fk+21 ° ' ‘ d d d d _' f1—11 fk+11 f1+1 ' ' ' f-Ml d ' d. d. d. ' ' fi-lk fk+lk f1+1k ' ' ' f-Mk d d d d ' f1-11 fk+11 f1+11 ° ' ° f-Ml, (M g N) x (M + N) matrix —_i d f01 G1: . I.d 0k d f01 L..._J 381 is the imaginary part of Y Also it should be noted 1' that the point z is not necessarily equal to the point d J J° Since VO # 0, Equation 2.30 has a solution only if E G ' C —D 27 Since 1 indexes over N g M terms, Equation 2.31 generates the N g M equations needed to determine the N + M suscep- tances, 81' The form of the equations generated by Equation 2.31 is like Equation 2.28 except the leading term is N ’B instead of H Y 11 _MJ 0 O (13 ‘Ikuz’x‘ J J J J 2.2.5.2 Reactive Loading - Frequency — Current Constraint The above case still assumes w to be fixed. For the case of several frequencies, let Nf be the number of frequencies and Nc be the number of current points. Then = N - N (2.32) assuming M + N even and that the same number of current points is used for each frequency. This somewhat limits the choice of M, N, Nf and NC. Assuming Equation 2.32 is satisfied, for each frequency the generating equation would be ' ' ' (2.33) 1 G1 V1 , , 0 i=-M,-(M-l),-°,2 + 1 i O i¢0 E C where f f f 28 for M > N C for N > M c _. d d f21 f11 d d + f 2 332 fig d d d fd 2+ll i+ll ° d fd £+l£ 1—12 d f.d £+li i+li X ' D :- 2.*-21 O O 0 H22 ’ ‘ Z Z f11 le f11 f2+21 ° ' ' _ z z z z Ci ‘ f1; fzj fiJ f2+2j Z Z Z Z f f f f LlNc 2N0 1Nc 2+2NC z z z z _- ' f1-11 fn+11 f1+11 f-Ml Z Z Z Z f1-13 f1+13 f1+1J ' f—MJ Z Z Z Z ° f1—1N f£+lN f1+1N f-MN C C C S— o Since Equation 2.33 generates only NC complex equations for M + N 2 each frequency, it takes Nf frequencies to have equations that are required. In Equation 2.33 the Bi's are still independent of w. Since the only elements which have pure reactive parts are capacitors or inductors, a logical frequency dependence for B1 would be either w or l/w. Thus in Equation 2.33 the reactances could become either B1 = chi or B1 = -l/Lin where J = l to Nf. In order to obtain a reasonable result, 30 the solutions to Equation 2.33 would have to be restricted to positive values for C1 and Li' In general this restriction may not be satisfied. CHAPTER III CURRENT DISTRIBUTION ON A LOADED RADIATING ANTENNA In Chapter 2 it was assumed that for an asymmetrically driven antenna the current distribution is known. This problem has been treated by many authors and is generally broken into two approaches based on the electrical length of the antenna. Current distributions for a short antenna and for a long antenna will be presented in this chapter. Since many antennas are monopoles and because of the formulation of the short antenna problem, only the asym— metrically driven short antenna current distribution will be presented. The asymmetrical case can be found in the literature. 3.1 Current Distribution On A Short Antenna There are several types of approximate current distri- butions for a short symmetrically driven antenna. The one presented here will be based on King and Wu's theory (1) and is valid for kOh < 3H/2 and Q = 2£n(2h/a) 1 8. 3.1.1. Vector Potential Of Symmetric Dipole Consider the symmetrically driven antenna in Figure 3.1 The axial component of the vector field on the surface can be shown to satisfy the equation 31 32 m Z=h w V9“: (3115 Z=2 Z T z=_o Vt: (S) Z=-£ 28-. ‘- V’ Z=-h Figure 3.1 Symmetrically Driven Antenna 33 (-d% + 2 _ k6 + + ) 5;? ko)Az(Z) _ _ w V1(6(z — 2) 6(z 2) - (3.1) The homogeneous part of Equation 3.1 has solutions in three regions h > z > z, 2 > z > -2, and -2 > z > -h given by Az(z) —J/eOpO[Cl cos koz + C Sin koz] h > z > 1 (3.2a) 2 Az(z) = -J/E;H6C3 cos koz 2 > z > -2 (3.2b) Az(z) = -J/eOuO[Cu cos koz + C5 sin koz].-£ > z > -h(3.2c) where -J/eopo is included to make the C's dimensional volts. From symmetry Az(z) = AZ(-z), thus C1 = CA and 02 = -C5. Since Az(z) is continuous at z = :1, from Equations 3.2a and 3.2b it can be shown (Cl - C3) = -02 tan koz. (3.3) 3Az(z) The scalar potential is given by «(z) = km __—55_ 0 Thus ¢(z) = —C1 sin koz + 02 cos koz h > z > 2(3.Aa) ¢(Z) = —C3 sin koz 2 > z > —2 (3.Ab) ¢(z) = -Cl sin koz - C2 cos koz> -2 > z -h(3.Ac) which satisfy the symmetry condition ¢(—z) = -Q(z). The driving voltage is defined as (3.5) V = MN) - cm') = -(c l - C3) sin koz + C2 cos kol. 1 3A Combining Equations 3.3 and 3.5 results in 02 = V2 cos koz , C3 = C1 + VA sin kol. Th erefore (3.6) Az(z) = -J¢eOuO(Cl cos kOZ+WNb/2)(sin kolz+£l + sin kolz-AI)). All that remains to be evaluated is the constant G1 which is done by requiring Iz(h) = 0. To this point, the develop- ment applies to either a short or long antenna. 3.1.2. Difference Equation In King and Wu's method, since 110 h I v t Az(z) = ER [hI(z )K(z,z )dz (3.7) where v 'Jkr r K(z,z ) = e r , r = /Qz-Z)2 + a2 (3.8) a difference equation of Az(z) — Az(h) can be defined. Using Equation 3.6, it follows that {:I(z')Kd(z,z')dz' = -333 [C1 cos kozifiVb/2)(sin k0|z+£l + sin kolz-zl) + U] (3.9) where -Jco h . . . U = Tn“ [huz )K(h,z )dz . (3.10) The difference kernel is Kd(z,z') = K(z,z') - K(h,z'). (3.11) 35 Since the right hand side of Equation 3.9 is zero at z = h, the constant C1 is U + V2 cos koz sin koh C = -[ cos k h o J (3.l2) and Equation 3.9 becomes h t t ' 3A _ I1 {h1(z )Kd(Z,z )dz - Co COS koh [V£(cos koz cos koz sin koh -CD2)cos koh [sin kolz—2|+ sin kO|z+2|])+ U(cos koz - coskoh)]. (3.13) 3.1.3. Current Distribution It can be shown that h . . , f Iz(z )KdR(Z’z )dz m Iz(z) (3.1Aa) -h h ' t ! IhIz(z )KdI(z,z )dz m cos(l/2)koz -cos(l/2)koh (3.1Ab) where Kd(z,z') = KdR(z,z') + JKdI(z,z'). Thus Equations 3.13, 3.1Aa, and 3.1Ab suggest that the approximate form of the current distribution should be 1(2) = IV(Z) + Iu(z) + ID (3.15) where Iv(z) = Iv(cos koz sin koh cos koz -(l/2)cos koh[sin kolz+£| + sin kOIz-2IJ) = IVMOZ (3.16a) 36 Iu(z) I F = Iu(cos koz - cos koh) (3 1102 ID(z) IDFOZ' = ID(cos(l/2)koz - cos(l/2)koh).(3 Substituting Equation 3.15 into Equations 3.1Ua-b the following definitions can be made: h i v t [hIV(Z )KdR(Z’Z )dz = IV(Z)¢dR(Z) é Iv(z)"’dR (3° h , , ' IV Iv [hIV(z )KdI(Z’Z )dz 2 ID(Z)IdeI(Z) a ID(Z):Ede (3. h ' ' . {hlu(z')KdR(z,z )dz = Iu(z)deR(z) = Iu(z)1pdUR (3 , v . . Iu . Iu {th(z )KdI)z’Z )dz = ID(Z)IBYdUI(Z) = IU(Z)‘1‘3¢dUI (3' h , , IhID(Z )Kd(z,z )dz = ID(z)wdD(z) é ID(z)wdD. (3. .16b) .160) 17a) 17b) .17c) 17d) l7e) Noting that the integral on the right hand side of Equation 3.13 equals AHpO-IEAZ(2) — Az(h)] and using Equations 3.15 and 3.17a-e, the result is -1 _ “Huo [Az(z) - Az(h)] - IdeRMoz + IudeRFoz 1 + (IDwdD + JIdeI + JludeI)Foz ° (3'18) If this expression is substituted into the original differential equation (3.1) in the form _ 2 JAHk Anuo 1[—9§ + k 2][A (z) — A (h)] = Orv [5(2—2) + 6(z+£)] dz 0 z 2 Co A -JwAZ(h)] (3.19) 37 then 2 -IV¢deo cos koh[5(z-g) + 5(z+2)] - IudeRko cos koh 2 + k0 (IDWdD + JIdeI + JIquUI)((3/“)COS(1/2)koz (3.20) Junko - cos(l/2)koh) = — Co (V£[6(z-2) + 6(z+£)] - JmAZ(h)). The coefficients of the 5-function terms must be equal, so that Junvk IV = (3.21) CowdR cos koh which leaves -1 IudeR cos koh - Anpo Az(h) - (I + jI DwdD deI + JIu‘deI)' ((3/A)cos koz - cos(l/2)k0h) = O. (3.22) Since Equation 3.22 must be true for all z, the coefficient of((3/A)cos koz — cos(l/2)koh) must be zero. Thus ID‘pdD + JIV‘PdI + 31ude1 = O (3°23a) and _ -l IudeR cos koh — Anuo Az(h). (3.23b) To find Az(h) Equations 3.15 and 3.7 are needed. Using the same type of approximation as used for Equations 3.17a-e, the result is Anuo'lAz + Iuwu(h) + IDwD(h) (3.2a) 38 where -2 I ' I w (h) = f cos(2k )sin k (h+z )K(h,z )dz + sin k (h-A) V —h o o o (3.25a) h 2' 7 ' ' ' ' ' f cos koz K(h,z )dz + f cos koz sin kO(h-z )K(h,z )dz 2. -1 h 1 Y ' wu(h) = £h(cos koz - cos koh)K(h,z )dz (3.25b) 311d h t . v wD(h) = £h(cos koz /2 — cos kOh/2) K(h,z )dz . (3.250) Ccunbining Equations 3.2M and 3.23b to form one equation and ussixig Equation 3.23a, two constants, T and Tu, can be D de fined as follows: 1. == :2 = '3Ewd1(wduscos koh ' ¢u(h)) + deIwu(h)] (3 26a) [3 IV wdDTWdURCOS koh ' 1"um”+ JwD(h)deI L1 IV wdedeRcos koh ” “’ua‘”+ MDU‘N’dUI ' Timiss using Equations 3.26a, 3.26b, 3.21, and 3.15, the approximate current distribution along the antenna driven by Iidentical voltage generators, Vn, at z = :2 is ( JAHV2f(z) I Z) = (3.27) z cowdRcos koh where f(z) = Moz + TuFoz + TDFoz' (3.28) witflfwoz, Foz’ and Foz' given in Equations 3.16a-c. 39 3.1.A. Evaluation Of Constants All that remains to be Specified is the w functions introduced in Equations 3.17a-e. Since the w functions represent the ratio of a component of the vector lootential to the current, the desired ratio is obtained at tide maximum of the appropriate current. For deR’ deI’ “QiD’ and de this maximum is at z = 0. Thus from Ek1uations 3.17b—e wciUR = (l-cos koh)-l f:(cos kaLcos koh)KdR(o,z')dz' (3.29a) h ' 1 v chD = (l-cos kOh/2)’1 [ (cos kOZ /2 - cos kOh/2)Kd(O,Z )dz ‘h (3.29b) -1 h , v v uuitJI = (l-cos kOh/2) fh(cos ka-cos koh)KdI(o,z )dz - (3.29c) -1 -9' i g ' ukiIf = (l—cos kOh/2) [hcos koz sin ko(h+z )KdI(O’Z )dz 9, ' , ' + sin ko(h-£) lgcos koz KdI(o,z )dz (3.29d) h ' ' ' + JACOS koi sin ko(h—z )KdI(O’Z )dz . Since in the range h i z : O,MOZ may have two relative nuLXiJna, the definition of wdR is more complicated. The first rmixiJnum is at z = h — A/U when h—z : A/A and at z = 1 when h-Z- < A/U. The second is always at z = O. The definition Inadfé by King and Wu is in terms of an average of the vector pOtentials . A0 Thus lMoowdR(O)l + ll‘dozl‘dewl)I was = (3.30a) IMOOI + No.1! where zl = h-(A/A), when h-g > (1/A), and 21 = 2 when h-z < A/A and where -1 '9‘ v t v wdR(z) = (MOZ) [ cos koi sin ko(h+z )KdR(z,z )dz -h 2' V ' ' + sin ko(h-£) f cos koz KdR(z,z )dz (3.30b) "R. h v c t + 1 cos koz sin ko(h-z )KdR(z,z )dz 9. In particular, MOO = sin ko(h-£) and MOZl = cos koi when 21 = h - A/A, and MOZ - sin ko(h-£) cos koz when 21 = 2. 1 3.1.5. Special Cases Two special cases need to be considered: 2 = O and koh = n/2. The first case is that of a center driven antenna. Since as 1 + O the driving voltage becomes 2V2’ thus V0 is equal to 2V1, and Equation 3.27 becomes J2HVO Iz(z) = [sin ko(h-|z|) + Tu (cos ka-cos koh) cowdRcos koh + TD(cos ka/2 - cos kOh/2)]. The second case is that of a half wave antenna. The «expression for Iz(z) becomes indeterminate because of the cos koh in the denominator. An alternate form of Iz(z) is ‘thus needed when koh is near H/2. A1 If T and T are redefined as u D , Tu + sin koh cos koz Tu = - cos k h (3.32a) 0 TD To' = 35m (3'32“ 0 which are finite at koh = H/2, thus Junv2 _ ' = v _ I _ Iz(z) cowdR [MOz Tu (cos koz cos koh) (3.33) + TD'(cos 1/2 koz - cos kOh/2)] where (3.3“) MOZ' = sin koh cos koi - 1/2(sin kolz + 2] + sin kolz-£|)- From Equations 3.26a-b and 3.32a—b, Tu' = - {[wdD(wV(h) — wu(h)sin koh cos koz) + wdDdeRCOS koh sin koh cos koz — ij(h)o (3.35) (de - deIsin kbh cos k02)]/[(wdD(deRcos kOh-wu(h)) + deUIwD(h)) COS kOhJ} and - 'JIWdIIWdURcos koh - wu(h)] + deIwV(h)] T v _ . . . 6 D wdD($dURCOS kOh-¢u(h))¥jdeIwD(h) cos.koh (3'3 ) Noting that at koh = H/2, wu(n/U)cos koz = wV(H/A), and de = cos kol w Equations 3.35 and 3.36 reduce to dUI’ cos k 2 o T , wdDdeR u = woD¢u(A/“) _ deUIwD(x/n§ (3.37) A2 dedeUR T ' = (3.38) D wdDwu(A/u) ' deUI¢D(A/U) which are both finite. 3.2 Current Distribution On A Long Antenna The approximate solution for a long asymmetrically driven antenna presented here will be based on papers by Wu (2) and Shen, Wu and King (3). The solution is valid for antennas whose shortest arm is Z .15). To follow the -Jwt original papers closely, the time dependence of e will be used. 3.2.1. Current On An Infinitely Long Antenna Consider an infinitely long center-driven antenna with its driver at z = O. The axial component of the vector field on the surface can be shown to satisfy ( 32 + k 2)A < > - +Jk°2 v s< > ( ) 5:2- O 22 - u) 0 Z. 3.39 Thus “ V Jk IzI A(z) = 3:0 e o for all z. (3.u0) 0 But )1 °° v t I A(z) = 3% [mdz I12 )K(z-z ) (3.A1) where H K(z) = 5% f do[22 + (22 sin (9/2)2:|-1/2 (3 Ala) '“ 2 2 1/2 . expfjkofz + (2a sin 9/2) 1 J. r49 ’43 Combining Equations 3.140 and 3.141 gives 2HV 0° ' v I Tgejkolzl = I dz IOSZ )K(Z-Z ). (30142) 0 '00 To solve Equation 3.112, let Re have a small positive imaginary part which will eventually be allowed to approach zero and define the following Fourier transforms f(;) = fwdz Im(z)e""jtIZ (3.1433) _rm for 12(5) is unjvoko 2 - c2)K‘(c) 20:) = . (3.147) Co(ko All Tofindlgz),the inverse transform of Equation 3.“? is taken. Thus 3 2 3 (3.118) _. 1C V :2 1(2) = glfif I(c)eJCch = 4-9- 2 82 _ <12; oo 00 C Co 0 Co(kO - c )K(c) where Co is the contour shown in Figure 3.2. Contour(%)is chosen so that the inverse of Equation 3.u5 resultszhithe proper value. Also it can be shown that K(c)==nJJO[a(kO2 — g2)l/2JHO(1)[a(k02 — c2)1/2]. <3.u9) Thus Equation 3.A8 is completely defined, but is not in a usable form. If it is assumed (1) that the antenna is thin i.e., a/A << 1 and (2) that the characteristic distance for variations of A(z) is >> a, then Equation 3.A9 can be approximated by K = 290 + 3n - 2n[(ko2 - c2)/k02] (3.50) where §%)== £n(2/koa) - y and y = .57721566. Using Equations 3.50 and 3.148 and deforming CO so that it is wrapped around the branch out at z; = k0, it can be shown that the major contribution to the integral comes from points near I; = k0. Thus IOSZ) can be approximated by V J 00 -2k Zn (z) = —‘?-——e3kolzl[ 9—0—— [(20 — 2m + J3H/2)-l °° CO 0 n (.0 -(2Cw - inn - JH/2)-l]dn (3'51 'here Cw = 2n(l/koa)- y. “F - ‘ "lCl huh..- “5 Imas(c) Right Branch cut Figureji2 Left Branch Cut 0 Real (5) The c Plane And The Contour CO - r' 1‘; 1i. 1&6 Because of e'2koZn in the integral, it can be shown that thetumerlimit can be replaced by e-Y/2kolzl. Integrating Emunim13.iland using the new upper limit the result is: I(z)='VJ§fl§len[l - 2“J J (3 52) w o :0 20m + £n2kofz| + y + 33n/2 ' for large koz. Forsmmll ka, the input conductance of the infinitely long antenna is approximately (3.53) 2 — £2 11 l. _ '2 _ _ ‘2 Ga, - Co £n(1 + Cw) + 12[Cw £n2) (Cm 2n2 + M) 3- To obtain a formula for I§z) when koz is small, the term '1 1/2) £n2kolz] must be replaced by 2n(k0|z| +-«kbz)2 + D ) - O, the real part I! To find D it is required that when koz - of Equation 3.52 divided by V0 and Equation 3.53 do not differ by more than l/Cw3 in the limit as ka approaches V! _ 27 Thus for all koz, zero. If this is done, D = e . VOJeJkolzl I(z) == £n[l - 2HJ/(2C + £n(k |z| + ” CO w 0 + /?k z)2 + e‘2Y + y + 1.5 HJ)]. (3.5a) 0 .3.2.22 Reflection Current At The End Of A Semi- Infinite Antenna IIf i(z) is the normalized current on a semi- O and the other end ‘.nfinite antenna with one end at z t z = on and is excited by V = on at z = on such'that the “7 amplitude of the incident current is unity, then i(z) for koz not too small and CO deformed around the branch out at C = k0, can be shown to be k _ _ CZ 1(2) = fiEL+Hko>J 2 I, 2 e3 2 __ dc (3.5561) Co(kO - c )K(c) where -— 1 in E’( ) = -:l [m-g ' £EELE—l' (3 55b) 4" C 2113—00—5 C C' _ C ° 0 Comparing Equation 3.55 with 3.U8 gives i(z) = —R;§z)/VO (3.56) for large kz, where C _ _ O -2 R — _fi [L+(ko)] . The approximate value of [Ei(ko)]-2 can be shown to be [Lnkon — 2% + Jn. (3.57) From Equation 3.56 it can be seen that -R is the ratio of the reflected current to the incident current and that the reflected current away from the end behaves Just like the current of an infinitely long antenna. 3.2.3. Current On An Asymmetrical Finite Antenna Section 3.2.2 suggests that the current on a long finite antenna may be expressed as the superposition of an outgoing wave, EAZ) and two reflected waves which are DPOportional to Iéhl + z) and I§h2 - 2), respectively. 1%“ 35-”? u8 If tflua coordinates are chosen such that the ends are at z = 'JEL and z = h2, and the driving point is at z = 0, then I(z) = I§z) + CdI‘jh1 + z) + CuIéh2 - z). (3.58) If it is assumed that the reflection coefficient R at the end of an antenna is the same as that for a semi-infinitely long antenna, then Cd and Cu can be evaluated. Since at z = -h1,R is the ratio of reflected to incident waves and since the amplitude of reflected waves is C V0 and the d amplitude of incident wave is Iéhl) + CuI§h2 + hl)’ the result is CdVO -R = . (3059) lihl) + Cu££h2 + hl) Similarly, at z = h2 CuV -R = O o (3.60) Téh2) + Cd£§h2 + hl) Solving Equations 3.59 and 3.60, C = _R[i§hl)/VO-Ri5n2)/v0;§hl + h2)/VO I (3.61) 1 - R2[;;hl + h2)]2/V'O2 I£h2)/Vo-RI§hI)/VOI§hl + h2)/VO 1 - R2ii§hl + h2)32/VO2 C = —R[ ]. (3.62) This completely defines Equation 3.58 and gives an approxi- nnte distribution for asymmetrically driven antennas. If a distribution is desired for the symmetrical antenna, it can be superimposed using Equation 3.58, km hit, and h = hit. 1 2 . Aldus“ ij CHAPTER IV RADIATION PATTERNS OF SHORT AND LONG ANTENNAS Since different current distributions were derived for the short and long antennas, different radiation pattern expressions will have to be found. A.l. Radiation Pattern Of A Short Antenna Because of the simple form of the current for a short antenna, the radiation pattern will be found by using Equation 3.27 and the usual far field approximations, ' koRo >> 1, RO >> h, R = R0 - z cose (phase terms) and R = R0 (amplitude terms) where RO is the distance from the center of'the antenna to the field point. If this is cknue,.it can be shown that the radiation pattern, Pm(e) is V c k h Ifin(e) = m g g sine I I(z)eJkoZ cosedz (A l) —h where I(z) is given by Equation 3.27 or 3.33. Thus three integrals must be evaluated h ‘f Mozejkoz 0086dz = I (4.2) -h 1 A9 .~c-l:___.fi__’n--An-nu n '-H 50 h . f (ccns koz - cos koh)e‘]koz COSGdz = I2 (4.3) -h h Jk z cose I (ecu; ka/2 - cos kOh/2)e 0 dz = I3. (A.A) Eknfli Equations A.3 and A.A can be evaluated easily and can be shown to equal to sin koh(l + cose) sin k0h(l - cose) 12: + k (l + cos a) k (l — cose) o o (A.5) 2 cos k h sin(k h cose) _ o o k cosO o and sin k h(l/2 + cose) sin k h(l/2 - cose) I = O + O 3 ko(l/2 + cose) ko(l/2 - cose) (A.6) 2 cos kOh/2 sin (koh cose) k cose 0 Using Equation 3.27, Il becomes h (A.7) I1 = cos k 2 sin k h f cos k zeJZko COSGdz -(l/2)cos k h. o o -h o o h Jzk cose h Jzk cose [I sin kolz + zle 0 dz + f sin kolz-zle o -h -h which can be shown to equal dz] 51 sin koh(l + cose) I1 = cos koz sin kohf ko(1 + cose) sin k h(l - cose) + o ] - cos koh (A.8) ko(l - cose) sin k 2 sin k 2(1 + cose) sin k zsin k £(l-cose) [ o o + o o k0(l + cose) ko(l - cose) cos koh(l + cosO) cos kO£(l + cosO) — cos k02( - ko(l + cose) ko(l + 0050) cos k h(l - cose) cos k 2(1 — coso) + 0 — O )1- ko(l - cose) ko(l - cose) Reducing to a common denominator and simplifying, I1, I2 and I3 are found to be I2 = 2 [cosesin koh cose(koh cosO) - cos k ho k cosesin e O O (u 9) sin(koh cosO) ° I3 = 2 2 [2 cosGsin kOh/2 cos (koh cosG) kocosO(l-A cos 0) (14.10) — cos kOh/2 sin(koh cose)] (£1.11) 2 I =-———-——{cos k 2 cos(k h cose) - cos k h cos (k 2 cose)l l kosin2O o o o o '- . -31 IL)! mun—M1 52 Replacing I1, 12 and I3 in Equation 11.1, the result is Vmsine = r E3n(9) WdRCOS kohL81n2e(cos koi cos(koh cose) - cos koh cos(k02 cose)) + u 2 . cosOsin e (14.12) (cosesin koh cos(koh cose) - cos koh sin(koh cose)) TD + 2 (2 cosesin(kOh/2)cos(koh cose) coso(l-A cos a) - cos(kOh/2)sin(koh cose))]. If Equation “.12 is inspected, it can be seen that Equation “.12 is indeterminate if e = O, n/2, H/3, or 2H/3 or if koh = n/2. If koh = n/2 then Equation 3.33 must be used in Equation 4.1. Thus for koh z n/2, I1 is h h I1 = sin k h cos k 2 f eJkoZ COSGdz - 1/2 I (sin k |z +2] 0 o -h -h o + sin kolz — £|)ejkoZ COSOdz (H.13) which reduces to 2 sin koh cos Ron 2 cos(koz 0059) 11 = sin(k0h cose) - 2 k0 cose k0 sin e (A 1A) 2 cos k 2 . + —————7?- (cos k h cos(koh cose) + cosesin koh° k0 sin e O sin(koh cose)) ”a? .i‘ A...“ ”In. '_ 53 or‘ _ 2 r Il - 2 Lcosecos koh cos(koh cose) k0 cosOsin O - (u.15) +- Z‘> —h. If it is assumed that the main contribution to the integrals comes from the vector potential on the antenna surface, then __ h V A(k cose) 5 f -Jfibuo[cl cos koz - 7?(sin k0|z+2l (4.25) + sin kolz-2|)]e-JZkocosadz which is very similar to Equation 4.7. Using the integrals evaluated to find Equation 4.8 sin k h(l—cose) sin k h(l+cos0) o + o ) l- cose l+cose sin k 2 sin k 2(l-cose) sin k 2 sin k 2(l+cose) _ V ( o o + o o m l-cose 1+cose Eo“o k 0 A(ko cose) = -J [C l( cos k 2 cos k 2(l-cosa) cos k 2 cos k 2(l+cose) + o o + o o l-cose l+cose cos koz cos koh(l-cose) cos ko2 cos koh(l+cose) l—cose l+cose Alltflmt remains is to evaluate Cl' 57 IFor a.semi-finite antenna with one end at z = 0, Wu (2) has shown that I dz f,(c)[K_(c) - A(O+)/J(c+ko)] = 0 (14.27) C on f dzAz(z)e-JCZ and E+(c) is given by 0 Equation 3.55b. _ o where A_(§) = If again it is assumed that Az(z) = 0 for 2 outside the antenna, then the following functions can be defined: ' z ' ' - - -JCZ T (z ) - é ch+(§)[£dze cos koz + Egfigj (4.28) . . ° _ 2' S (2 ) = f ch+(C) I dze'JCZ sin koz , (4.29) C o 0 Since it has been assumed that z = 0 is at the lower end of the antenna, Az(z) must be rewritten as (4.30) Az(z) = —J/eouo[(Cl cos koh + V cos ko2 sin koh)cos koz- m H(2h - z) + (Clsin koh - Vm cos ko2 cos koh)sin koz H(2h-z) -Vm(sin ko(h+2) cos koz H(h+2—z) - cos ko(h+2)sin kaH(h+2—z)) -Vm H(h-2-z)[sin ko(h-2) cos koz - cos ko(h—2)sin koz)]] where H(z) = 1 z 1 0 = 0 z < 0 Substituting Equation 4.30 into Equation 4.27 and using Equation 4.28 and 4.29 the result is 58 ' (C cos koh + Vm cos 1402 sin koh)T (2h) 1 i + Uh Shikoh - Vm cos ko2 cos koh)S (2h) ! i - Vm(sin k0(h+2)T (n+2) — cos ko(h+2)s (h+2)) — Vm(sin ko(h—2)T'(h-2) — cos ko(h-2)S'(h-2))= 0. Solving for C1 ' I C1 = +Vm[cos k02(cos kOhS (2h) - sin kohT (2h)) Q 1 + sin‘k0(h+g)T (h+2) - cos ko(h+2)S (h+2) ' 1 + sin ko(h—2)T (h-g) - cos ko(h-2)S (h-2)]/ V ' [cos kOhT (2h) + sin kOhS (2h)]. (4.31) (4 V 1 1 Both S (z ) and T (a) have been approximated by Shen (5) and are given by S'(z') -'.[-yi + y (z') - y3(z')]/2 T'(z') [y; + y2(z'> + y3l/2J where y; = 113/(:21 - 2H2) . a (z') ' y2(z >= zn. 1e— ‘\ 100.. 200-- 300-0- 1; #004- m 3 500-- b0 0 £3 600«ra.= h = . 3 700«-dl = 0.6251 g 02 = 1.251 04 800”"d3 = 1.8751 du = 2.5A 900-1 20 = 86.u - J 152.60 1000‘:— J l J A A A I I l ' r I 0.51 1.01 1.51 2.01 , 2.51 2.751 Position,'Z = -J 22H.A0 23 = 3 9880 = J 16980 _ Zu = J 5890 Figure 5.11 Current Distribution For A Transmitting Antenna On Which The Current Was Specified At Two Points (Reactive Loading). 85 5.5.6 Reactive Loading - Frequency and Current Constraint Figures 5.12 and 5.13 show the frequency dependence of input impedance of two reactively loaded antennas. In both cases the input impedance was Specified to be 500 at 60 and 70 MHz. Figure 5.12 is the case of frequency independent loading and Figure 5.13 is the case of frequency dependent loading. Like the previous example of frequency dependent loading, the resulting input impedance curves are very similar. Unlike the previous example, the antenna described in Figure 5.13 can be easily built from available materials, four sets of inductors and a metal rod. It should be noted that like the previous reactive loading example, the solution was not easily found. Several combinations of loading points, antenna lengths, and frequencies were tried before this particular example was found. 5.5.7 Resonance Loading In Section 2.2.2 relations were derived for resonance loading and for the instabilities in that resonance. For a given set of antenna parameters and loading points, a family of resonance loadings exist. The instabilities, however, are unique for each set of parameters. Figures 5.1M and 5.15 show typical values of Z and Z2 1 as a function of frequency for the two types of insta— bilities. As can be seen, the real part of either Z or 1 86 200 1 ; IL IL 100.. ReIZ I o 0 I —v i ~100.. ~200¢b C: \I Ile | o o N —A00-. . a = 0.00635m h = 2.75m d1 = 1.0m Z1 = J 392U0 d2 = 1.5m Z2 = J 8220 .500.. d3 = 2.0m Z3 = J u0530 d = 2.5m Z = J 13760 A u -700 g : 141 % 50 60 10 80 Frequency (MHz) Figure 5.12 Input Impedance vs. Frequency For A Transmitting Antenna (Two Frequency - Reactive Loading - Frequency Independent). 200 100 -100 -200 g -300 -A00 -500 -600 -700 Figure 87 ‘- <1- WRE(20) 1- 1. Im(ZO) a = 0.00635m h = 2.75m - d1 = 1.0m L1 = 3.88 uh 02 = 1.5m L2 = 2.00 uh 1- d3 = 2.0m L3 = 6.63 uh du = 2.5m Lu = 3.78 uh L 1 1 1 50 60 70 80 Frequency (MHz) 5.13 Input Impedance vs. Frequency For A Transmitting Antenna (Two Frequency - Reactive Loading - Frequency Dependent). 0.6.. 0.“.- 0.2-- 3 5 AH N (8‘03" 22R -0.u~~ -- -2.5 -0.6«b 15-3-1 HES —0.8-p qr- -500: w a up -705 a = 0.00318m h = 0.25m (11 = 0.1125m d2 = 0.1675m TI. -1000 --—12.5 r 1 1 1 -15.0 60 120 180 2H0 Frequency (MHz) Figure 5.1“ Loading Impedances vs. Frequency For A Trans- mitting Antenna To Maintain A Resonance Instability (Finite Voltage). 89 11 1 1 1 1 5.0 0.3-11- 0.2-- +b205 0.1 ‘- ”c; 55 A _O.ldL or! N \d: qD-205 m -0.21- H a -o,3.. HF din-5.0 V ;: -O.L1qr 3 a = 0.00318m _7 5 Z2I h = 0.25m 7' ' d1 = 0.1125m d2 = 0.1675m ~-—10.0 --—12.5 1 1 l 1 3 60 120 180 2b0 300 Frequency (MHz) Figure 5.15 Loading Impedances vs. Frequency For A Trans- mitting Antenna To Maintain A Resonance Instability (Zero Coefficient). 90 Z2 is negative in each case. Thus for the usual passively loaded antennas, these instabilities are of no consequence, but if active loading is employed they could become critical. Figure 5.16 is a graphical solution of the resonance equation for f = 2A0 MHz. Because of the complex nature of the graph, a brief explanation is in order. Each circle on the line parallel to the real 22 axis, Z2R’ is a curve of constant real Z 2 Similarly each circle 1’ lR' along the imaginary Z2 axis, 221’ is a curve of constant imaginary Z Z In addition to the circles there are 1’ 11' two asymptotes, ZlR = -22.3 and 211 circles approach. Since none of the constant 21R circles = 6ND, which the intersect except at the point (-3.9, 1.2“ x 103), any other intersection on the graph gives the values of Z1 and Z2 for resonance, as shown in the circled example. The common intersection, however, is not a solution but equivalent to the condition of Y = 0 for the 2-dimensional hyperbola XY = 1. Unlike the instabilities, the resonance loadings do not have to be active. Because the asymptotes are skewed with reSpect to the axes, there exists a small region in which the real parts of both Z and Z are positive. Thus 1 2 the possibility exists of designing an antenna which has greatly enhanced radiation using only passive elements. 91 mccmuC¢ wchuHEmcme < pom cofipfiocoo MCaomoq monocommm no COHpsaom awoficampo wfi.m mpzwfim o.mI Aexvmmm BIS m1 3m 9% mam- o..m- mun . . 1.1. . .m.mmu . am . comm w I 83 u mm \c 10R. n+ can u HN ,oam \\ It v n! a — EmNHH.o u U Hm N + mmN Emm.o u n mam ucwpmcoo NH NH I ma . I Hm MN I N Ewamoo o I a HH .Nn + .No . am: ozm n .H N pcmumcoo .llllll . 11 11 1 0 u v u m.» CHAPTER VI MATHEMATICAL FORMULATION OF A MULTI-LOADED RECEIVING ANTENNA To this point only multi-loaded transmitting antennas have been considered. It will be shown that with the addition of one term, the theory can be extended to receiving antennas. 6.1 Matrix Formulation Consider a multi-loaded receiving antenna of length 2h, radius a, and with N + M arbitrary loads and a central load illuminated by a normally incident electric field E0 as shown in Figure 6.1. Replacing the loads by the voltages across and separating the total antenna current into a component of current which is induced by the incident field on the corresponding unloaded antenna and a component of current which is excited by the voltages across the loads, the problem becomes equivalent to the antennas shown in Figure 6.2. It can be shown that ' Iu(z) = Eofu(z) (6.1) and from 1.1 N It(Z) =1§_Mvif(w,a,h,di,z). (6.2) 92 Figure 6.1 Multi-Loaded Receiving Antenna 9A n 1N : 5 VN-l ’Q A - A 11 :o V2 . 8 I0 IL (GIG-GIGIGI [9'] (one: Figure 6.2 Voltage Equivalent Of A Multi—Loaded Receiving Antenna 95 Therefore the total current at any point is It(z) Again to find the used. Thus Eofu(dJ) + (YJ i=-M 'fids, the relation Y d N + 13 1§_M 1%3 + f )VJ 1 ij i N ' Eofu(z) + X Vif(m,a,h,di,z). V (6.3) i = -It(di) is (6.“) Comparing Equation 6.“ to 2.2 it can be seen that Equation ' 6.“ differs only by the extra term Eofu(d now an unknown rather than a known value. runs from -M to N, J) and that’VO is If J again including J = O, the result is M + N + 1 equations of the form of Equation 6.“. matrix form, FRVR where _ d £11 + Y1 d le - d d f1-1 d f1-M + GREO = 0 d d ' fN1 f01 d d ° fNN + YN f0N d d ' ° fN0 f00+Y0 d d - ° fN-1 f0-1 d. d. - fN-M fo-M (6 . 5) d d f-11 ' f-Ml d d f-lN f f—MN d d f-10 f--M0 d d d. d. f-l—M ° f-M-M+Y-M Writing these in 96 F—' --1 — — fu(d1) V1 '. V. fu(dN) N I GR = fu(0) and VR = VO ' fu(d_1) V_l f'(d ) V. —M -M L _ L .1 Since FR and VR differ from F and V by the addition of the fd 10's, V0 and Y0, the number of complex unknowns for the receiving antenna is two greater than those for the transmitting antenna and the number of complex equations is one greater. Thus one additional complex constraint equation will be needed. Otherwise the analysis of required constraints follows that of the transmitting antenna. 6.2 Constraint Equations Since the transmitting case requires N + M complex constraints, the receiving antenna needs N + M + 1 complex constraints. Also since the field pattern of the unloaded rod illuminated by an electric field can be shown to have the form, Pu(0) = Eogu(w,a,h,0), (6.6) all the constraints outlined for a transmitting antenna can be applied to a receiving antenna. 97 6.2.1. Load Impedance Constraint Since for most practical applications, it is desirable to specify the central load impedance, one constraint equation could be Yo equals a constant. This constraint alters one of the equations in matrix 6.5, N d d ' _ (fOO + YO)VO + 2 inVi + Eofu(0) - O (6.7) =-M i¢0 where YO is now a known value, and reduces the number of unknowns by one. Thus there are 2M + 2N + l unknowns and N + M + 1 equations which reduces the number of additional constraint equations to M + N. 6.2.2. Scattered Field Constraint It is desirable to be able to control the scattered field of a receiving antenna. Thus a possible constraint would be to specify the scattered field in M + N directions. Using Equation 6.6 and the first equation in Section 2.2.“.l., the equation for one direction would be N PT(GJ) = Eogu(w,a,h,03) + §_Mvigi(w’a’h’93)' (6.8) Applying Equation 6.8 in M + N directions results in N + M equations. But there are M + N + l unknowns. The remaining equation can be generated by specifying one more direction, or it can be Equation 6.7. If one more direction is used the resulting equations are like those in Section 2.2.“.1. and the solution follows that outlined there. .....-..i that If Equation 6.7 is used, the resulting set of equations in matrix form is 77 RV = éSE 98 R o where _v;;1 77- . VR - vO , s - V. '(e ) g + L_ N_ u M'N fu(0) and ‘- _7 7 ' ( > '( > 8_ 9 g 9 R = M J O J 7 ° 7 . 8_M(0m+N) go(eM+N) d d f—MO f00 + Yo 7 where g (93) = g (w,a,h,0J). by 8'1 Multiplying Equation 6.9 - P gu(ej) - PT(GJ)/EO T(GM+N)/Eo ' .— gN(el) g$(ej) 7 gN(OM+N) d fN0 .1 gives the solutions for all the Vi's. (6.9) - . ‘ 99 Since one of the equations in matrix 6.5 has been used, care must be taken to find the Y 's. If three 1 7 7 new matrices Y, FR’ and GR are defined as r‘8 d d d d -1 f11 ' fN1 f01 f-11 ' f-Ml d d d d d F' = le ' fNN f0N f-lN f-MN R d d d d d f1-1 fN-1 f0-1 f-1-1 f—M-l d. 8 8 d 8 f1-M ' fN—M fo-M f-l-M ° ° ' f-M-M A —_I -‘ -1 Y1 . 0 0 0 . 0 0 . Y 0 0 . 0 Y = N 0 0 0 Y—1 0 0 . 0 0 0 . . . Y_M L. — and _.' ._ fu(dl) ' . ' ru G = R 7 r (d_l) ' . fu(d_M) 100 then matrix 6.5 less one row (Equation 6.7) may be written as 7 R (Fé + Y)vR + 0 E0 0 . (6.10) 7 It should be noted that FR but are M + N by M + N + 1 matrices. Thus they do not and Y are not square matrices have inverses. To find the Yi's the same procedure as outlined in Section 2.2.“.1. can be used, namely: YVR = -(GREO + FRVR) (6.11) 01” 1 g 1 Y = -(G E + F v )/V . (6.12) 1 R o J=—M HiJ RJ R1 J¢O 6.2.3. Current Constraint Since on a receiving antenna the current at the load is of primary concern, it would be desirable to specify the current at d = 0. This condition, however, only supplies one constraint equation and M + N + l are needed. Additional current points could be specified as was done in Section 2.2.“.2., but a more interesting case is to specify I(O) at several different frequencies. From Equation 6.7 and 1(0) = -YOVO z N z ' fOOVo +1§_Mvif10 + Eofu(0) = 1(0). (6.13) i#0 But Equation 6.13 is not in a useable form. If CF(w) is defined as CE(wl) = le(O)/Eo (6.1“) 101 then Equation 6.13 becomes N z ' z _ 1; Mviin + EOEfu(0) - CE(1 + foo/YO)J — 0. (6.15) i#0 Applying 1(0) = -YOVO and Equation 6.1“ to Equation 6.10 and combining the results with Equation 6.15 gives BR . VR = O (6.16) where _'d d d f11+Y1' fN1 f-11 d 8 d f1N fNN+YN f-lN B = R d d d f1-1 fN-i f-1-1+Y-1 d. a 8 f1-M ° fN-M f-l-M Z Z Z L_f10 fN0 f-10 d ' d ‘— 8 . ° d . . . f_MN (fu(dN) - CEfON/YO) d I d f-M-l (fu(d-1) ' CEfO—l/Yo) rd +Y (f'(d ) - 0 rd /Y ) - - - -M-M -M u -N E O-M o z ' z f_MO (fu(0) — 0E(1 + foo/quJ 102 and Like Equation 2.27, Equation 6.16 has a solution only if the determinant of B is zero. This produces one equation R with N + M + l unknowns. Since, however, YO is usually known, there are only N + M unknowns in Equation 6.16. Thus if 1(0) is specified at N + M frequencies, the required N + M equations will be generated and all the admittances can be found. 6.2.“. Current And Scattered Field Constraint The final type of constraint to be considered will be a combination of the current and scattered field constraints. Again the current constraint will be to specify the current at d = 0. If the scattered field is specified in L directions, then the resulting constraint equations in matrix form are: c v =0 (6.17) where gi(el) gimL) 10 ‘ g1-1 ' g1—1 . f . g_M(01) (gu(01) - (PT(01)/EO + CEgo(el)/Y . g;(01) (0 (0 d 1-10 1 L g};(0L) f ) ) 2 k0 103 g f k+1<0 d k+10 L ) ) g1+1(91) (0 ) g1+1 d f1+10 L .1 O) . g_M(eL) (gu(0L) - (PT(0L)/EO + CEgO(OL)/YO) d . f -MO ' z (fu<0) - CE(1 + foo/YO) 10“ and Following the same method used to obtain Equation 2.30, define the matrix B as i 105 d d d d f11+Y1 ° ° fkl f11 fk+21 Bi = d ° 8 8 d. flk fkk+Yk fik fk+2k d d d d .ufli fki fii+Yi fk+2i . d d d d I ° f1-11 fk+11 f1+11 ' ' f-Ml (fu(d1) CE f01/Yo )' d. d. d. d. I ° fi-lk fk+1k fi+lk f-Mk (fu(dk) I CE f0k/Yo ) d d d d I fi-li fk+11 f1+11 f-Mi (fu(di) ' CE f01/Yqfl where k = -(M - L - l) for M > L + l k = N + M — (L + 1) for L + l 1 M and i = k + l, . . ., —M. B1 is a M + N - L by M + N + 1 matrix and C is a L + l by M + N + 1 matrix. Thus if they R are combined, the result is an M + N + l by M + N + 1 matrix V = O (6.18) 1 1 = k + 1, . . ., (-M) whose determinant must be zero. Equation 6.18 generates L + 1 equations with M + N unknowns. Thus Equation 6.187 IWJSt be used for P frequencies such that 106 (L +1)P = M + N (6.19) to obtain the required number of equations needed for a solution. CHAPTER VII CURRENT DISTRIBUTION AND SCATTERED FIELD PATTERN OF AN UNLOADED ROD In Chapter 6 it was shown that the current and scattered field of an unloaded rod was needed to solve for the current and scattered field of a multi-loaded receiving antenna. In this chapter the induced current for both a short and long unloaded rod will be derived. The derivation will be for a normally incident wave. The derivation of other than normal incidence can be found in papers by King (59) and Yu and Shen (10). 7.1 Vector Potential Of An Unloaded Rod For an unloaded rod of length 2h and radius a illumi— nated by a normally incident electric field, E0, as shown in Figure 7.1, the vector potential is given by d2AZ 2 3802 2 + 80 AZ = - w B0 (7'1) dz the solution of which is = _ / — 2 AZ J Eouo [Cl cos koz + EO/ko] h i z i h. (7. ) Equation 7.2 is valid for both short and long antennas. 107 108 ’m 251—. <—- I 1V: Figure 7.1 Unloaded Rod 2h 109 7.2 Current Distribution On A Short Rod For the short rod the procedure outlined in Section 3.1 will be used. From Equations 3.7 and 7.2, it follows that h ' ' ' E fhlrod(z )Kd(z,z )dz = — g53[cl cos koz + E9 + U] (7.3) .. o 0 where U is defined by Equation 3.10. Since at z = h the right hand side of Equation 7.3 is zero cl = - [U + EQ/kOJ/cos koh (7.u) so that Equation 7.3 becomes h [hIrod I t 1 '- Jun (2 )Kd(z,z )dz — Co cos koh[cos koz - cos koh] (U + Eo/ko). (7.5) Equations 7.5, 3.1Aa and 3.1Ab suggest that the approximate form of the current should be (7.6) Irod(z) = IEI(cos koz - cos koh) + IER(cos Roz/2 - cos kOh/2) Substituting Equation 7.6 into Equation 7.5 and using Equations 3.17c-e, the result is IEIEUdUR(cos koz - cos koh) + jdeI(cos ka/2 - cos Rob/2)] +1 _ = 3““ r _ . ERwdD(cos Roz/2 cos kOh/2) cos kohLcos koz cos koh] (U + El/ko). (7.7) Since Equation 7.7 is true for all 2, then j“’dUIIEI + IERwdD = 0 (7'8) 110 and _ JUN IEdeUR ‘ Cocos koh(U + Eo/ko)' (7'9) All that remains is to find U. Substituting Equation 7.6 into Equation 3.10 and using Equations 3.25 b-c results in 3:0 Combining Equations 7.10 and 7.9 and using Equation 7.8, IE, and IER can be found. Thus 3w hnE IEI = dD O (7.11) wdD(deR COS koh ’ wtfh)) + MmedUI Coko and A w . HE - dUI o IER ‘ .(7.12) wdD(deR COS koh ‘ wu(h))+ 3¢D(h)de1 z:01‘0 If new variables, TE1 and TER’ are defined as E _ Mn 0 o E An 0 ER ER goko then Equation 7.6 becomes (7.15) ['11 um - __._2 _ Irod(z) - Coko[TEI(cos koz cos koh) + TER(COS ka/2 - cos koh/2)]' 111 7.3 Scattered Field Of A Short Unloaded Rod Once Irod(z) has been found, the scattered field for a short rod can easily be found. Since Irod(z) has the very same form as the current of a transmitting antenna, with the use of Equations “.1, “.9 and “.10 it can be shown that JEO sine TEI = _ r r Prod(e) k cose L 2 Lcosesin koh cos(k0h cose) 0 sin 0 TER — cos koh sin(koh cos®)] + 2 (l—“ cos 0) [2 cosesin kOh/2 cos(koh 0080) (7.16) - cos kOh/2 sin(koh cosO)]. Like Equation “.12, Equation 7.16 is indeterminate if G = 0, H/2, + n/3, or 2H/3. For 0 = 0 it can again be shown that Prod(0) = 0. If e = H/2, then Equation “.17 is used and Equation 7.16 becomes JE _ _ _43 _ Prod(H/2) - k0[TEI(sin koh koh cos koh) + TER(2 sin kOh/2 - koh cos koh/2)]. (7.17) For e'= H/3 or 2n/3 only the T term is indeterminate. sin k h _____2_ 2 ER It has been shown that it reduces to kOh/2 - 112 Thus . 1E T P (0):.- O'EEI r 0d kO cose sine ' ' T(cos 0 sin koh cos(koh cos a ) ' - cos koh sin(koh cos 0 )) + sin k h o 2 )sin e']. (7.18) + TER(kOh/2 - 7.“ Current Distribution On A Long Rod The approximate solution for the long rod will be based on a paper by Shen (11). Unlike Shen, only the normally incident wave will be considered. 7.“.1 Current On An Infinitely Long Rod Jwt time Applying Equation 7.1, altered for e- dependence, to an infinitely long rod, the equation's solution is E A (z) = j —9 for all z . (7.19) z w Since U m t v v Az(z) = E% 1 dz réz )K(z-z ) (7.20) V where K(z-z ) is given by Equation 3.“la, “HJEO m t 1 v C k f dz Imrod(z )K(z—Z ). (7.21) O O "°° Applying the Fourier transform to Equation 7.21 and using Equation 3.“6, the result is _ “nJE 1mr0d(;)i(;) = Co k: 2n5(;). v (7.22) 113 Solving for I(C) and taking the inverse transform, 3E I- (z) = “A - 9‘. (7.23) rod ; — o k K(o) 0 But from Equation 3.50, K(O) = 290 + JH thus “n JEo 1 I”. (z) = —— . (7.2“) rod Co k0 (290+ 3H7 7.“.2. Reflection At The End Of A Semi—Infinite Rod If the semi-infinite rod is in the upper half plane with its end at z = 0, and if it is illuminated by a normal E field such that I rod(z) = l, the reflected current can be expressed as k ejczdz 1 (z) = ——9 E (o) _ . (7.25) r 2“J ' (0(kO—c)cL_<;) If again it is assumed that the contribution to the integral in Equation 7.25 comes mainly from C = k and 0 that CO can be deformed around the branch out at z = Cko, Equation 7.25 becomes k E (0) 3:2 1r(z) = 21? _ ' 8 dz- (7.26) L+(ko) C2(ko-c)cK(c) which is approximately ir(z) = -RS I§Z)/VO (7.27) where R =E_g.__I::_(_9_). S 2H * L+(ko) 11“ For large koz, E (o) :1———— = 20w + 2n2 + jn . (7.28) L+(ko) 7.“.3. Current On A Finite Rod To find the current on a finite rod the results of the last two sections and Section 3.2.2. must be used. Away from the end, the finite rod will seem like an infinitely long rod and this should support a current like Iwrod(z)' Near the ends Ierd(Z) will produce a current like Iéz)/VO from both Equations 7.27 and 3.56. Thus current one finite rod should be of the form Im(z + h) Im(z - h) Irec(z) = Iwrod(Z) + CR1 VO + CR2 vO ° (7°29) To find C and CR2, Equations 7.27 and 3.56 must be used. Rl At 2 = -h, the incident current would be I0° (-h)- Im(2h) rod + CR2 ——V——— which would produce a reflected current at o z = -h of Im(0) Im(2h) Im(0) Irefl = ”Rslmrod('h) v ’ R032 V V ° (7'30) 0 o o 1m(o) But by definition Iref = CR1 V0 , thus Im(2h) CR1 = ‘ RSI”r0d(-h) ‘ RCR2 ‘“V;"“ (7°31) Iw(2h) Similarly at z — h,cR2 — — RS Imrod(h) - Rch-—1V———. (7.32) O 115 Solving Equations 7.31 and 7.32 for C and C R1 R2 yields: R I». (h) CR1 = — S r°d = CR2. (7.33) 1 + RI..(2h)/vO Simplifying Equation 7.29, the current distribution for a finite long rod becomes (7.3“) on + co -- S (I (Z h) + I (Z h))] 1 + RIm(2h)/vO vO v R Irec(z) = I""rod(z)[l - 0 since I0° (z) is a constant. rod 7.5. Scattered Field Of A Long Rod To find the scattered field of a long rod, the same type of method as used in Section “.2 will be employed. From Equation 7.2 the vector potential, corrected for the e.Jmt time factor, is AZ = J/quOECl cos koz + EO/kO] - k i z i h and from Equation “.23 ( K(ko cose) P ) = 3w _ sine rec G K(kO cose) If again it is assumed that the main contribution to the integral is the vector potential on the antenna's surface, then (7.35) h I JVHOSO [Cl cos koz + EO/koje‘JZkOcosedz -h Ill A(kO cose) 116 which using Equation “.5 is _ JC /u a sin k h(l + cose) sin k h(l-cose) A(k cose) = 1k 0 O( O + O ) o l + cos@ 1 - cose 32E /p e sin(k h 0056) + o o o o . (7.36) k 2 cos@ 0 All that remains is to find Cl' This can be done by again using Equation “.27. If Az(z) = 0 for 2 outside of the antenna, the functions defined by Equations “.28 and “.29 and a third function v'(z') = I dcf+<;) Imdze‘JCZ(H(z'-z)-e‘3koz) (7.37) O O are needed. Rewriting Az(z) so that one end is at z = O, Az(z) becomes Az(z) = j/pon[Cl(cos koh cos koz + sin koh sin koz) + EO/kO]H(2h - z). (7.38) Using Equations “.28, “.29, “.27, and 7.37, the result is . . (7.39) Cl(cos koh T (2n) + sin koh S'(2h) + EO/ko v (2h) = 0 01" _ ' ’2k h c - -(EO/ko)2j v (2h)/(yl + y2(2h)eJ o 1 + y3(2h))e'3koh 7 using Equations “.33 and “.3“. Only V (2h) needs to be ' _ evaluated. It can be shown that V (z) is equivalent to Pl(ei = n/2) as defined by Yu and Shen (10). 117 Thus V'(2h) = -ZJ y3(2h) + 2n/(20w + £n2 + 3n) (7.“0) and (7.“1) = Jk h C +Eo/ko2e o 1 (-2J y3(2h) + 2n/(2cw + £n2 + JH))/A where A is defined by Equation “.“0. Finally combining Equations 7.36, “.23 and “.2“a sine C kO sin koh(l+cose) I 1 ( P (0) = -(E /k ) . rec O O - £n(sin0)) 2 E0 1 + cose (91 sin koh(l - cose) + ) + l - 0030 c050 sin(koh coso) l. (7.u2) Equation 7.“2 has two indeterminate points 9 = O, H/2. At a = 0 it can be shown that Prec(e) = O as it should be. At 0 H/2 the last term approaches koh and Equation 7.“2 becomes C k _ l o Prec("/2) — -(EO/k091HF§—E; 2 sin koh + koh]. (7.U3) CHAPTER VIII ADDITIONAL NUMERICAL EXAMPLES To this point all the numerical examples have been for transmitting antennas. This chapter will give some examples for symmetrically loaded receiving antennas. 8.1 Resonance Loading In Section 2.2.2 the conditions for resonance loading on a transmitting antenna was derived. In Section 6.2 it was found that all the constraints of a transmitting antenna can be applied to a receiving antenna with only slight modifications. The modifications for resonance loading are that the second loading impedance is replaced by the central load impedance, 20; V2 is replaced by V0, V0 is replaced by ED, and the zero coefficient instability is dropped. Figure 8.1 like Figure 5.1“ shows the values of the load impedance as a function of frequency for the finite voltage instability. Figure 8.1 shows two things of interest: 1) the real part of central load is positive and 2) it is near 509, a typical impedance of a recieving antenna. Since for a receiving antenna, V0 is one of the unstable voltages, this instability point could prove to be extremely undesirable. 118 119 l L L I j Y t T 80 ‘- df3.0 6O ._. db2.0 “0 4p d 1.0 20 .. r H i N p. E :9 :3 ”Q N g -20‘r ‘b-1.0 "L‘O-I- 1--2.0 -60'P a = 0.00318m \ —80 h = 0.25m \\ “ 3'0 d1 = 0.1125m \ \ ZOI Z1R % 1 11 1 -“.0 60 120 180 2“0 Frequency (MHz) Figure 8.1 Load Impedance vs. Frequency For A Receiving Antenna To Maintain The Resonance Instability. 120 Figure 8.2 is constructed like Figure 5.16 and gives the other values of impedance required for resonance. Like Figure 5.16, it also has an area of passive loadings. Solving the equation given in Figure 8.2 for 21R = 0, it can be shown that resonance can occur if ZOR i 209. Thus with the right reactive load at d the antenna can 1’ be taken in and out of resonance by adjusting the central loading. Unlike the transmitting case, the receiving antenna coefficients are dependent on the direction of the incident radiation. Thus the receiving antenna can also be taken in and out of resonance by varying the direction of the incident radiation. Since resonance enhances the voltage of the central load, this would indicate that an extremely sensitive and narrow beamed receiving antenna could be made. 8.2 Scattered Field Constraint Figure 8.3 shows the desired (dashed line) and the resulting scattered field (solid line) for a receiving antenna of half length .7). Like the field pattern constraint for a transmitting antenna, Figure 5.“, the field was specified at.four points. But unlike the transmitting case, the central impedance was fixed at 509 for the receiving antenna. This last constraint removes one of the problems with the transmitting case, uncontrolled input impedance. Thus the receiving scattered field contraint can produce the desired scattered pattern as well 121 mcsouc< wcfi>fiooom < pom cofipfivcoo wcfiomoq momeOmmm mo soapSHom HmoHSQMLo m.m opzmfim Aaxv moN md o..m SH 0% m..o m..o.. our. mu? EmmHH.o u o amm.o u s 30H x N.H- u p 1 .. Emamoo.o u d moa x w.H u o \..m.o- oom \ \ x \ 1 - _ . I .\ I / OOH \. z 7.. / n _ . \ com ) .r xoom /V,/ :\\ \\ :m o m. llll'l I- mow llllll 'll/l/l’é , \\\\“\\ .Om /\ \\\|\a - 'l'l lllllll l1 3 Ho \ \\ \ A.//// f How I N u .N \\ \ \ / / / .. m0 m0 \ x / 1! 2.0 + N u .N \ _ . / ./ o.H 5.:H + mHN u mmN \ . ./ cos mom 1 N u .N / \ cow / I 1' / \ // I'moH Ho mo Ho mo NHN + NAN . HHN NHN + NHN . mHN HAN pcdpmcoo IIIII Ho 1 mo I . Ho mo 1 . .No . .Nn - .Nm + .No. .mHN pcdymcoo r d u T N d 4 1 Com .l“ . ,2 x \ //” ‘\ // \ / \ .12-H- / \\ / \ / \ .10.. / / \ / \ \ i: .08-- \ 3 \ (LB \ .061. / ——————— Actual Pattern \ \ / ————— Desired Pattern \ / \ .ou.. / \ / \ / \ , a = 0.0106) \ .02 1 / h = 0’71 \ ‘i \ /‘ \ / \ / \ 1 s 1, 2% : s : 1 4 10 20 30 .“0 50 60 70 80 90 6 (Degrees) ZO = 509 Zl = -80.8 + J 3119 d1 = 0.11 Z2 = -37.0 + 3 5029 d2 = 0.291 Z3 = 16.6 + 3 6289 d3 = 0.“01 Z“ = 168.9 + J 5829 d“ = 0.55) Figure 8.3 Field Pattern For A Receiving Antenna Specified At Three Points (PT(O) = sin 29). 123 as maintaining a reasonable central impedance. However, like the transmitting case, it also has negative real loading impedances. 8.3 Current Constraint Unlike the transmitting current constraint, the receiving current constraint is designed to control only current at the central loads and the value of the central load. Figures 8.“, 8.5, 8.6, and 8.7 show the current distribution for an antenna of half length 2.75 meters at four frequencies: 300, 320, 3“0 and 360 MHz. The specified currents and the resulting currents are given on the figures. As can be seen, the currents outside the neighborhood of the central load vary widely. Thus good control of the central current and load is obtained by this constraint. Therefore the objective of constructing a frequency rejecting receiving antenna with constant central loading can be achieved by this constraint if active loading is acceptable. 8.“ Current And Scattered Field Constraint The final example of the versatility of the methods outlined in this thesis will be current and scattered field constraint. Figures 8.8 and 8.9 show the scattered fields and current distributions, respectively, for a receiving antenna for which the backscattered field was Specified to be zero at two frequencies, 300 and “00 MHz, and the central current was specified to be 10 ma-m/V at 300 MHz and 12“ z = 509 R2 = -10959 ' L1 = 1.17 uh R2 = -2119 L2 = 1.82 uh “0 R3 = 5759 L3 = l.“9 uh ‘* Ru = -2339 L, = 0.u26 uh 301 *r :0 H- I-' 5.1. N [.5 20‘ 10- = 0.00635m = 2.75m 0.625m 1.25m 1.875 2.5m -10 1)- It(Z) (milliamp-meter/volt) 0:00-04:79) 4:"me I -20. Re(Iz(z)) -301r --"--Im(Iz(z)) It(0) It(0) -“O f 0.5 1.0 1.5 2.0 2.5 2.75 Position, 2 (Meters) Figure 8.“ Current Distribution For A Receiving Antenna For Which The Central Load And Current Were Specified At Four Frequencies (f = 300 MHz). 1.0 pa - m/V (Desired) 1.8 - 3 0.10 ua - m/V (Acutal) AL 1 125 0.25 i % : % ‘L 20 = 509 R1 = -10959 L1 = 1.17uuh 0 20 +_ R2 = -2119 L2 = 1.82 uh R3 = 5759 L3 = 1.“9 uh R“ = -2339 L“ = 0.“26 uh O 15 “r a = 0.00635m h = 2.75m d1 = 0.625m d2 = 1.25m d = 1.875m 0.10 db 3 _ du - 2.5m S H g 0 05 4)- \. L. (D 1.) (D 7 Q. s ~~4 5 I /\ I N I F$0.05 .. I I I I I -0.10 q- \ / \ I L] —0.15 d- Re \ I p B 5 "I' ‘ a) I E . E /' \ | :1 76 \ g \\ / I V \// g b \1>-5 I I4 _10 up Re(It(Z)) f = 3“0 MHz -20 . 1 1 L7 1 U I I ' T 0'5 1.0 1.5 2.0 2.0 Position Z (Meters) Figure 8.6 Current Distribution For A Receiving Antenna For Which The Central Load And Current Were Specified At Four Frequencies (f = 3“0 MHz). 127 25 : i I i I For Values of 20 Loads See 1* Figure 8.“ 15 «I- 33 10.. H O ;> \. S... (D 4.) 7 5" o. g -~‘ «-I I)- :I ,,/ 'r'I M E ’13 If -5... ~108r Re(It(Z)) '15‘P ______ Im(It(Z)) It(0) = 1.0 ua-m/V (Desired) f = 360 MHz It(0) = 1.01 - 3 0.02 ua-m/V (Actual) '20 i I i I *I 0.5 1.0 1.5 2.0 2.5 Position Z, (Meters) Figure 8.7 Current Distribution For A Receiving Antenna For Which The Central Load And Current Were Specified At Four Frequencies (f = 360 MHz). 1287 3.0.. h = .7m f = 300 MHZ a = .0106m d1 = 0.1m III- (12 = 0.29m (13 = 0.“m dLI 3 0.55m 2.0.b T: m __ 3_ 1.0.. : : t : : : :2 : 0 10 20 30 “0 50 . 6O 70 80 90 0 (Degrees) (a) 3.0 R R1 = -95609 gf‘ L1 = 0.373 uh 232 0-- R2 = -1979 f = “00 MHZ H L2 = 0.106 uh :; R3 = 13109 Of) Tb L3 = 0.192 uh __ R“ = -57509 1 0 L“ = 0.179 uh 0 10 2O 30 “0 50 60 70 80 90 0 (Degrees) (b) Figure 8.8 Scattered Fields For A Receiving Antenna For Which The Current And Radiation Pattern Are Specified At Two Frequencies: (6) f = “00 MHZ. (a) f = 300 MHz I(Z) (Milliamp-meters/volt) I(Z) (Milliamp—meters/volt) 60 129 db 1 l I 1 {I- ————Re(I(Z)) Im(I(Z)) '60 I I 1 T 001 003 005 0.7 Position Z, (Meters) (a) ;_ 0.8 «I- For value of loads see 0.6 ‘- Figure 8.8 O.“ 0.2 -0.2 -0.“ -0.6 4 ; 0.1 0.3 0.5 0.7 Position Z, (Meters) (b) Figure 8.9 Current Distributions For A Receiving Antenna For Which Current And Radiation Pattern Are Specified At Two Frequencies: a) f = 300 MHz And h) f = “OOMHz 130 0.01 ua-m/V at “00 MHz. Again with the use of active loading, the desired conditions were obtained. Thus if active loading is allowed, the current distribution, the scattered fields and the central load can be controlled as a function of frequency. Since these are all the important characteristics of a receiving antenna, the objective of improving the receiving characteristics of a linear antenna has indeed been achieved. CHAPTER IX CONCLUSIONS In the preceeding chapters a method has been developed to improve the transmitting and receiving characteristics of a linear antenna. Matrix equations to describe multi—loaded transmitting and receiving antennas were derived. Further constraint equations were developed which related the loading impedances to the desired antenna characteristics and the characteristics to the loading impedances. In particular, relations were developed for a transmitting antenna such that: l) M + N loading impedancescnuibe Specified and the current and field pattern could be found, 2) M + N current points can be specified and the M + N complex loading impedances could be found, 3) M + N field pattern points can be specified and the M + N complex loading impedances could be found, “) the input impedance can be specified at M + N frequencies and the M + N complex loading impedances could be found, 5) any of the above can be specified at (M + Nl/2 and the M + N reactive loading impedances could be found, 131 132 6) resonance loading can be achieved and no characteristics could be found. In addition to the above relations, constraints were developed for a receiving antenna such that the central load impedance could be specified and relations 2) and 3) from above be applied. The first three relations are linear and presented no problems in obtaining a solution. The remaining relations were non-linear and may or may not have had one or more solutions. Since in general these non-linear equations could not be solved analytically, two numerical methods were employed: 1) a minimization method for finding the neighborhood of a solution and 2) a linear method for finding the solution. Examples of each of the constraints were presented. As a result, it was found that in each case of complex loading, the desired characteristic could be obtained but only by active loading. When reactive loading was required, it was found that if a solution existed, the results were as good as the case of active loading. However, the requirement of reactive loading severely limited the chances for a solution. The most interesting result of the study, was resonance loading of a receiving antenna. It was found that a single reactive load and the proper adjustment of the central load impedance could create an antenna with high gain and a very narrow beamwidth. In this resonance loading, however, it 133 was found that certain values of loadings would cause the antenna characteristics to become unstable. Thus multi-loaded antennas can achieve improvements in receiving and transmitting characteristics normally requiring extensive arrays. 1. 10. 11. BIBLIOGRAPHY R. W. P. King and T. T. Wu, "Cylindrical Antenna With Arbitrary Driving Point," IEEE Trans. Antennas Propagat., Vol. AP-l3, pp. 711-718, (Sept. 1965). T. T. Wu, "Theory Of The Dipole Antenna And The Two-Wire Transmission Line," J. Math. Phys. (New York), Vol. 2, pp. 550-57“, (July 1961). L. C. Shen, T. T. Wu, and R. W. P. King, "A Simple Formula Of Current In Dipole Antennas " IEEE Trans. Antennas Propagat., Vol. AP-l6, pp. 5“2-5“7, (Sept. 1968). L. C. Shen, "The Field Pattern Of A Long Antenna With Multiple Excitations," IEEE Trans. Antennas Propagat., Vol. AP-l6, pp. 6“3-6“6, (Nov. 1968). L. C. Shen, "Current Distribution On A Long Dipole Antenna," IEEE Trans. Antennas Propagat. (Commun.), Vol. AP-l6, pp. 353-35“, (May 1968). S. M. Robinson, "Interpolative Solution Of Systems Of Nonlinear Equations," SIAM J. Numer. Anal., Vol. 3, pp. 650-658, (1966). E. E. Altshuler, "The Traveling-Wave Linear Antenna," IRE Trans. Antennas Propagat., Vol. AP-9, pp. 32“-329, (July 1961). D. P. Nyquist and K. M. Chen, "Traveling Wave Antenna With Non-Dissipative Loading," IEEE Trans. Antenna Propagat., Vol. AP-l6, pp. 21-31, (Jan. 1968). R. W. P. King, "Current Distribution In Arbitrarily Oriented Receiving And Scattering Antenna," IEEE Trans. Antenna Propagat., Vol. AP-20, pp. 152-159, (March 1972). I. P. Yu and L. C. Shen, "Modifications Of Scattered Field Of Long Wire By Multiple Impedance Loading," IEEE Trans. Antenna Propagat., (Commun.), Vol. AP—19, pp- 55“-557, (July 1971). L. C. Shen, "A Simple Theory Of Receiving And Scattering Antennas," IEEE Trans. Antennas Propagat., (Commun.), Vol. AP—18, pp. 112—11“, (Jan. 1970). APPENDIX A-1 ~uz< “.mox.mhz.~oz.do_.- aqua ~ox.mos._os.~oz.zz.z.- o~.<.uo.ouu.ou.o<<.>oo.<<<.puo.mm.<<.m».u~.d~.~<.~L xuadzoo moo_:o.mouxo.m3~zo.m>mzo xmudzoo xu zo_m~omad mamaoo .nvouu..m.o.m.ou..m.m.mm..o~.ao..m.o.o<<..m.d.>oo H .Ao.som..wm.m.<..m.3..o.oz..m.xu..m.o.o.<<<..o.o.~moum. mzh mu duaoz .umqo oz~>nwomm uxh uzo .umqo oz~»p_zmz.c undo: .mo_o do mm~o Hu_os .hmozm «on mzo .ozoa xou omuN .zo_»:m_mpm~o pzmmmao .goz .»4u>_howdmum so go .NN .uN .o> .zpozms .>ozu:ommu .mzo_»ozunommu mom ouoofl .muozap.~zo< urh no mozuozmaua >ozm2cumu .oo~ .m»z_o1 oz_o<04 no mwmzaz .z .mumozuncumu no mumzaz .xz .mzo_p<:au pz_~.dxm.m> me oz_>m<> mpz_ m< oz.>m<> m»z_4om z~wuwm o~ru¢moouro."Aha.H.mvou uox.m>—tu:m~:oro..mauroIIUtmmnoru.tmuouzo.¢_~Iu.- hzmmd .mzofizu.m~omro.m>~ro.x.tom..x4dzuu>N NN.m~.om ouzuacmmu mo .hz~\.h—.zUNt.ZZthZV<NVaxuualem>nAzzobZZV<< om mm Ch 06 m>uafiZZthZV<< Alfiufizz om Ch 00 Agoawofivun Am».mozoouu.xooom.\.b~.m0Nt.h~.zz.~.444tghuou0>DOIuazzomv44 NON or 0040.30.10x0um mm o» 00 Ah~.m.>ootu.zz.~044 mam Ch 00 .~.cu.zhzvum Ah~.fi.~.444uafi.mv44 zomufi mm 00 0az.~u~ mm 00 No Ch 00 Acoowo0az. um mzo~h430m m4wzu4lzoz mom whzwu0~uuwou wpDQZOU 0 mm Op 00 Amlow4.0azvu~ wazmhzoo unzupzou .hm.4.~.444u.bu.4.zzv444 44 Op 00 .hu.4u~0444u.h~.40044 cam Ch 00 Amoewomhzvmn zo~u4 cm 00 momuomn .Alxv mu UDZHhZOU m>lu4h~.ufiv>oo ¢ Op 00 m>uahmozz.ufiv444 4cm 0» 00 Ahzocmofifivuu zzuufi Au.owox0mn unto 4 o» 00 Ahmouv>oou~huozzv>oo ¢om~om~ .mlzvmm m>lu.h~.~0>oo mam Op 00 Aaoow.mhzvun 4 Op 00 m>u.p~.fi.m0444 0 Op 00 .hzoowofifi.u~ o O» 00 “Accuofifivum Am».moz.0mu.x.oom.4omoxom0130 4440 mom m 44 oom N4 4cm mom m4 ufi.~ufi Nma on :m o» 00 Amhzozwdauzvum ~ooluah¥oauzv<< 40.2m010¥vmu o>\.p~.Zzoah20444t.h~0m0NI.h~.mh20>oolu.zzoa02044Anoau.a0z.uu .hm.Zzsahzv444uazzom0zv44Acoowomuzvuu NNN oh 00 Ahmoahzv>OOInAZzoa02044 ~HN Op 00 .moamozhzvku .hm.fi.ahzv444u.fisauz.44 2onufi mm on ~IQUZ+HHQFZ szoaum 4m 00 wDZMFZOU Abnozzv>QOIuahzohzv44 O».Ahmozzo22044\Ah~022.22.444+Oo~0#.h_.mUNlahnoZZ.>OOIH.ZZoZZV<4 cum 0» o0.cocuozuzvm~ Ahmomozzv<<<flamskfi04< Z.~u— oom oo hxnufi AcoauoxUKVu— mom 0» 00 .oocwdmhzvuu Zzuufi mm oh so .uoowoNOfiva MDZHhZOU mzzmhzou ahuouv>oolu4hzouv44 AbdoZZoHv<<<fl.22.uv4< A--7 oma "m4 NNN mum mm mom cum oom No mm pom A-8 .43440.44:30400x4020+4~.—.4 upaazoo o 00\z3¢.—.ozu.~.4om 40 22.4"“ no 00 ou\.z.3¢30murom UU\.z.3tzo\.1010Nln.zz.z000 .z.ow.ufi.uu com 0» 00 .o.am.xhz.u~ .\\.m0024hb~z04 0404 024 hnmzurhm.x~.h4zmou con 00¢ N024ouaz~ hDQZH MHDQZOU co: pzmma .h—.H044u.~.z.mm ufi.4u~ co 00 «omfinhn .omlwco~¢hw0.~.mfi.44.o~.oo~0004Qp420 4440 zuufi 0>\.z.zz.~0444¢.zvaN+.¥.~0>00u.zz.~.44 z.—u~ MNN 00 m- 0h 00 0>¢.zz.zzv44u.zz.zz444 .z.~.>00u.hz.~044 ~¥.22.~0444NAZZ.~044 Axo—szzv444uamozzv44 zz.~u~ mum 00 zzuufi «Hm or 00 Anoamomuzvmu m—N 0» 00 zuufi .z.~0>00u.zz.~.44 2.4nu mo 00 N~N 0h 00 .~.00.mpz.u~ uDz—bzou A..103\.fi.40...mlfi.40.X4020+4~.~044u.~.~044 pm 0» 00 ...z.2..w.4o...4Iw.4o.x4azo.._.H.< d~.zz.~ pzmad om\.d~u.z.zz.>oo.ua~ m op oo ._.z.mm\.d~u.z.4.>oo.uQN m ch oo .._I_..z.mm\.d~u.z..414..>oo.ud~ cm 0» oo .4.ou.~. 04 NAN Op 00 .~.am.z»zvu~ omuuo._ua_.z.mm .o.o.ou.4.u.z.mm.mm.a: hzmmd N~.mN.h hzumd 00.44 hznma unzmpzoo .m.o~um.p4zmou .\c~.¢.m~wh\.¢.mumo.p4zmou .o.¢4mm.p hzmad ~a\.om~¢.mN.uwvmzuaN as ch 00 dNo.zz.z.00¢m>uaN ms 0» oo aNdomam>uaN ~NN 0h 00 .n.aw.apz.uu unzupzou ms 0» oo a~..ozz.z.mm¢m>ua~ «l1n322 oNN 0» 00 .hz.om.fi.m— Nb oboe .n.cw.1. um 4m».402.0uu.x.000.400.10001:0 4440 maz~pzou .x.s.n.ouu.m.ouu .z.3.~.ouu.~.uuu .z.5.~.ouu.~.uuu ch 0» 00 .hz.cw.fi. um es 0» oo .o.am.4oz. um .fiv4omuoom N: on 04 ms 0h oNN ANN #5 0h A-13 ..N.N04 020 UDZHFZOU m>.UN.QN.~« bzmma a~.N.«.444#.~o~.N0444naN .~.n.~.444uwN Amomsmv444um> “4.4.4 Nttmtfi¢oxnvh4zxou 40m hzuma UN.QN.- hzmaa .MN\0.ANMN .~.Nomv444luN\m>tawomonv444uwN 1N\0.~naN an."9—0444lm>\wN#-o~.N0444NQN Am».nozo0kusxooomo4omoromv030 4440 .N04omuoom m>umN .m».mozo0muox.oom.4om.rom.1:0 4440 4~04omnoom cocux A>h~4um4hmzu omm~ro~.xmvh4xmom Mom hzuaa wNoaN.- hzuma mN\0.~an AnoNoNV<<< lamonv>OO\A~oN0>OOQA~onoNv<<4flwN QN\0o~uQN Au.~.~0444 l.~.N.>00\.~o~0>00#.~.N.~0444NQN A>h~4um4pmzm N04h4o> whmzmmromox~2h4szL Nam hzuma mazthOU ucm o» 00 mDZ~hZOU A0.0~D®.Pz~ xmmh42 xu4m2o0 4 mm 04ah420 0 mcooom mrp do pzqzmzmubmo uxpxmc.x4.p» ~0000420 Aaw.h00.2.z.4ofifionu.mowuv04ah420 mzubnoxmnm A-l5 mm000420 40000420 0m000420 N0000420 4m000420 00000420 04000420 04000420 #4000420 04000420 m4000420 44000420 ,mcaoc4 mm 04 44 A-l6 h00u44.204 4cmlwoo4oh00.0o44.00.0.0.40040h420 4440 40.4.44n4fifi.44.mm 44 200903 02.22u3 44 00 204944 02.2294 44 00 44.204 wpn0200 0 4u<4 4I2l0zn022 4+zuzz 40.04.40.0400.4N0om04o40.0044 204020240 4.04.h00.00.44.24.44 4040200 .4 24 42040400000 0004000 02h 0240 0h 44 X40442 qu 00 0220400 024 0300 02h 00 00000 024 000232 000000 NI» w>40 0h 004030h0200 m4 m4 00h00> 0000p24 024 .042040400000 02h 00 x40h42 01b 04 4 .44 x40h42 02h 2000 0204h4300 0402440202 02» 000 mhzm40400000 02h 00h30200 0000 44.44.2.2.Nzo0200000 mz4h000000 0000 020 zmopmm Ao.om4¢40.\¢uamua4~m.um 02# 00 #2424200#00 0I#IN4.440#42000 00 #0200.#00.m.0.44.4 204040000 040000 400.44.44 204020240 404.004 204020240 0042040 204000>z4 x40#42 204040000 040000 0 .00.#00.2.2.44.fifi.44.00340040#42 024#000000 020 200#00 0024#200 m 4 0# 00 4 0# 00 42.00.42. 04 m 0# 00 4Nzo00.44. 04 #2040400000 #044 000 #00# 0 #00n444.204 400I00.4.#00.0.fifi.00.0.0.4.040#420 4440 44.2.4 0#D0200 0 434.44.44u43.4.00 0 40.04ufi4 03.4"? 0 00 44004u44 A-19 04000420 0:000420 #4000420 m¢000420 N4000420 ~4000420 03000420 0M000420 mm000420 OM000420 mM000420 #0000420 nn000420 "M000420 0M000420 0N000420 0N000420 NN000420 0N000420 0N000420 40000420 NN000420 ~N000420 04000420 0‘000420 00000420 0‘000420 4‘000420 m~000420 ~§~nzux z.~u~ N~ 00 >~.o~.o~ .moauvum .~.~.<¢p00uh00 z.~u~ «a 00 zmabmm am 0h 00 on hzuma s~.o~.cn 40000.0” .0up00 m~.m~.¢4 .m0u..z.z.40m0400 mu 4¢zu~az 2+zutaz «Izuuzz 22.0.4thmzouu.1.404u.z..04 zmz.~mfiuz : 00 20.004\.0.~. 02h m0 #0 .0:~:hzozm mzp :00 4a: 024 mm”: 0204 uxp mom on: .zoupammahmfio 00 00>h 02h m400~Z00 2 00h024z40 02» .000 #4 000404 024 .400 000040 .Iomtm Ih0z04 00 4ZZO~Z4 Z4 000 02h 200h00mH0 0:» Zn 200hh40 04000 0:» m0p00200 #400 Ah0.2.00.0Ih.N00.400.2000p400 0z~p00000m 00000420 40000420 mm000420 N0000420 00000420 00000420 04000420 0:000420 5:000420 Kuzh42 >b~20 4 0h 0000001 00 44 020 210h00 0oanauonv44 Zo~u~ mm 00 0o0fl.0.~044 zomufi mm 00 Zogum NM 00 .hmmx0 #02 0000 0mm0>2~ 200h0m 20~.~04u.0.—044 2+0u0~ 2.~u0 ON 00 Z._n~ ON 00 .z.zv4\.ml.4.zv40u.4.zv4 .4.004¢.0.zv4+mnm zom0zu0 MA 00 0~.0~.N~ .u0XI200H .0um 20Z.~0zu4 NH 00 ~+zu~0¥ mm mm an 00 ON Na mm on UUUU _ oh oo .°.o.h4.~on00~ 0103 owo.ua.-0.4~0.~0.Im0.~0.m0.:u.ou.m.o~0.~00 xm4azoo .m000 zoumzmzHo pzumanu 0:» mo ua4<> 01p m_ m» .0003 .mozm 01p «90 flu: oz< 0003 oZO4 01p 090 on: .zoahanahmHo 0o 00>» 0:0 m4oapzou z «00024140 01p .oom pq o0o404 ozq ..z.ou.x.oom. O ZIthm oomlfloom m>o000um> 2000000200n0~0 NN0¢00+~N0¢00+N0H0~0 00\AIN0#N0#0I~00¢1In00 00\.IN0#~0¢0|N00#00u00 .30oaN0N20000N00uNN0 .30..No~10000wm0n~N0 .30.N0N~0HN0 .30.N2000N~0NN0 230.~2000N~0u~0 oomltomumtom 000+200n~200 oomlxuN oomluoom .0~0000200um> 0 0h 00 “0.0.00.0000 Lu NN0¢00+~N0¢00+N0H0~0 00\~IN0¢N0#1I~0.#0IH00 00\.IN0#~0#0IN0.¢0IH00 00¢00I0o~n00 Immomuwo 230.2NIN20000NA0NNN0 AxquN¢~20000~H0u~N0 .30oNONHOuN0 .30.N1000N~0um0 .30.~2000N~0u~0 .30.:00t0.NON~0uINO oomnzomumxom 000.:00u0I00 oomlxuN N 0h 00 .0.0.b4.00000~ 01“} 00040423 100 hmwh 0 A-25 ..m.uu..oo.\.~rom¢._.uu+~zom.‘~.ous~u.tuqum> a“ zmapmm ..m.uu..om.\.mzoma._.um..:om..~.uuu~m.¢_ mg 0» ca .o.o.om.oom. mu pm zzapum .xua.n.ou¢.oo.\.mzom¢.~.ou.~xom¢.m.uu._m.¢H pg zmshmm .zu..m.um¢.on.\ANIom¢.~.ou.~1om¢.~.uu._m.au N" o» co .o.o.am.oom. um pm o» co .qo.o.m4..o.~\_auzom.mm<. La m:ou..~\x.mooumzom zuuxuugxom mazupzou m» o.~\...oomax.mm<.z_m...oom.x.mm<.zam.uzm.ouumu p» m» op oo o.~\...oomnx.mm<.z~m...oom.x.mm<.z~m..zuuxu¢zm:cuu~u sp oh oo ._o.o.u4..o.m\_muxom.mm<. ma quanzom mom pmmp o A o» oo .o.o.p4.oom.u~ mm"; oma ..xmmaa.o._.\.mm.~u.ouono.~.a~mum> Aunt—4+Ao.N.004<+30#o.Nvtoooouwo .30..x.zom..-mumu Ago..xurom..NHmu~u .30.:omco.m.-uuxmu ..uaguq..o.¢.094<.;u¢o.m.#:om¢o.om.\.oomu.¢__1uuHoHIu.4~ruu_a~zu.oI~0HIUHH0~IU .»z_4<>...o.xom.oom..~ouxuumonzu .»z_4<>.Ao.o.xom.oom..~o~xuu~ouzu .pz_4<>.As.o.oom.oomu..~o_ruu_ofizu .p2_4<>.a.c.oomu.zomu.uuofixo .~z~4<>.da.o.oomu.xomu.Im>HIUHm>HIU .pz_4<>.n.Iom.zom.oom.+m>~zuum>qu .pz_4<>.”a.zom.rom.oom..m>~ruum>~zu .hz~4<>._a.:om.oom.oomu..m>~ruum>~zo .pz~4<>.a.Iom.aomn.zomu.um>~zu .sz4<>.~n.zom.oomn.zomu.p zo_:o.~omru.m>_zu.pz~4<> xu41zou .oz_z >m ouzmuuo meagre ozq .nou_xu .>n~:u m4u omou u .mmo_zu.m~o_xu.m>_zu.oom.zom.lumo~IU .Iom.moothz~4<>lmD~IUHmD~IU .hZ—A<>.o.Iom.Iom.romI.umDHIU .hZ—J4).~l.Iom.IomoIonl.<3mvohzuzwo 4440 30~IU.m00~IU.mo~IU.mD~IU.hz~4<> x041zou coarhwz muozmz zu U szuumo OOIuIU ozw now u .moouro.m~3010.m13010.m0~10.m3~10.Iom.~zuuao~:u.4lmomruumamzo .hz~44>.~.Nom.rom.oom.+mouxuu10HIu APZ~4<>.~I.Nom.rom.oono+ma~ruumo~ru .hz~4<>.~I.Nomooom.ooml.¢aouruuaomro APZ~4<>.~.Nom.ooml.romloumouru Ahz~J<>.uI.Nom.oomluroml. d m.m.~ .2. mm o.m\.maa o.N\.N¢# x04axou .A MI» mm h2~4<> .xuaxvm o¢uz «CL 024 ..N\K.Z~mu.xvm .nuz mom ..N\xvmouu.xvu .Nuz mom ..x.z~mu.xvu .Huz IO..— oOomuaxvu oouz mom oaxvmouuaxvm onlfl! mom .1 >0 0m440¢h200 mu «Xv...— oamttw 024 :30 oh In: tomu 00hm mhzuzwm .pZuJ<>.t.Nom.romomuzo."moonu .hz.4<>.~.o.:om.zomu.uumoo~xu ..o.~\:on.mou-~.x.m:_zuuao~ru.onao_:uu:oaru .pz_4<>.o.o.zon.zomu.uoauzu .bz_4<>.~u.a.tom.xomu..mo~:uumo~:u ._z~4<>.m.zom.zon.xomu. m szhwm AAADocoOozoo.avm+ m .DocoOoNoOoovmvtAOouocoovKJQZU+AD.OoOoloOoovU¢aDoOocoNocoovUv ¢ tooN\AOoN\Nom#.caal.9oo.KAQzUvmme#A0oA.Ooo.xdaxolaA.D.o.o.>oo.m ovmt.DoOoOoxoOoovm.#AOodocoovxdatoo.3.o.o.>o0oovoo.DoooooKoOoovuv N to.N\.coN\Nom¢.¢o~oOocvxaatovametao.doOoOVXJQIUoAOoN\Nova~m a tamtt<00\aAN## h m.h.~ “MOI. mm o zxnpwm AAADoOoo.3.coovm¢ m ADoOoOoNoOoovmv#AOo~.0000K41209.390oao3oaoovUOADoOoOoVocoovUv ¢ #OoN\AOoN\Nom#AeomloOoOVXJQZUVQKMUI.AADoOooo>ocoovm+ m ADoOoOoxoooovmv#A00MacoovKJQZUQADoOocg>oooo.Uo“Doc-OoKoOoovUv N #:.N\A00N\NOD#AOo~oOoo.XJQ2001KMUIAOoN\N03vaU A #.N## m Zmthm AA.n. Q oom.¢ .NIZV mu m ZIDhmm .dcmoNODoIOfioIMBthAOoaoOoov N szhwm A-29 A-30 ozu Zmthm Acco.o.=.0 zauw I J0 zmwh I 440a0hz~ mzum QmHLHooz U A XMJQ£OU om» zothZDu ZKMhhqa oJmuu zothZDm ozm zaDhmm OoN\~a#~um> .-~\mNNUoOJUum> .Nom. quonu .m» zo_»uzam zmmppqa QJMHu «zzm»z< 0204 u .Non. zofipuzau .mmmx oouo<0423 0204 MI» mom hmm» U .Iom#~<#ooNivaxmuqu A .o.m.004.z~>.a~>.mx>.m:>.z~o.a~o.mo xuqmzou n».m».m~.m~.mo.~>.~N.~<.muu xwgazou .Nom.Ion. .Nom.zu x 024 x 01h Ihom mozuu I .xoqwa.z.zvr uzuhaozmam ozw szhmm m0\AIN>\uQ¢c.N+nI>¢~<#o.NIU#zm>umuU AwUtmr>+wU#~>+NI>.#~umr> «IOQQOoN.uNI> Alomtm A Zmthm w0\A2NU#AIN>ImU#ZM>U+1NU¢AQN>IMU#QM>~+AUU#MI>INI>+UU#~>U#WUV"mmU AMU¢MI>90Uta>+NI>U#—<#0oNum0 AANomiIomvoNZN> .ANomlromvouZn> “ANOQQIOmvouQM> AANonoromvouQN> .Iomto.N.umr> Aromao.N.nNI> «NomvaUHmU ANOm¢~z~ x U wbzuhZOU m mozmhzou m cgouafiouvx N~.~ufi m 00 NI—HN~ Zomum m 00 m 0» CU anohqoz. mu UDZAPZOU é .z.0\.—.0¢Uzwaowmm nh.o~.o~ .0Uu. um uUzwozmmma >Uzmaamzu 10m hmub ~NZOUH AuUH ZtNuzz ~+Zuaz ZOUHHOUH N\Hzn~Zfi «IQUZMIUZ NthuNmZ mz¢zn~z mz.~umz UDZHhZOU mp coon.¥.40 0h alummnz Z.~u~ ch 00 01m~ 0h A40m 4202> AZOUH.xm.3.4U.<.hz.Iz.Nz.z.4202> mznhaoamam A-39 N.Uaz.Nufi AoN oo z+~2¢amlzx0n32 .zzvzzuUz Izouuzz oaN 00 X#N¢UQZHIIZ hz.«u¥ com 00 Occum cooumm< c.3um< o.oum< .Ufi.mZH.NzU~mh 4420U mom hmwh mm.o.od hzumm mcouo.~aqu vahmomuo muo Auonm hzmmm mazubzou ..UIAmzmUAUU\U.mm2~ m0 20~h200 mom hmwh U Amsoum hzumm MDZHFZOU O .fivaooaquUuauvdo m2\Hfl0 m2o~2.mznu o 00 mem<~m<> IUZ no 20~h wuzmmwkmmo L0 ZOuhUzwaommu .ooo~00\.ooonom\.oooqow\.ooo~om \oo.o~00\.ooo~0®\.ooo~0®\.ooouom\oooo~00\.ooo~00\.0ocuom \oooo~00\oooc~0®\.0o0~00\.ooo~00\oooo~00\\oooc~w0\oooo~wm \.ooo~mm\.o.o~um\.ooo—wm\oo.o~um\oooo~um\.ooonum\.ooo~mm \.oooamm\.ooo~mm\.ooo~mm\.ooo~mm\.ooomum\.ooo~mm\ooooammUh no 20~h~0 mom hmwh U co: 0h 00 .o.~.cwomxm.u~ 0: 0h 00 .oonohoozouuv mu nozoumuzoou MNMQ’ .\¢.N~00~\.¢o¢nw.h th h< zouhUZDu «(wzu4lzoz urh no 0044) NIP m0h<40U4 IP H 01h 2H 00N~m Ih u th Zn m