A healthy urban forest is important for both human health and environmental quality. There is currently a lack of technology that can analyze living trees in their natural environment without destroying them. This thesis presents a microwave tomography imaging system that is intended for use in several forestry applications. Recently, there has been an increased demand for imaging systems that do not use ionizing radiation but produce comparable accuracy and sensitivity to traditional imaging techniques. Microwave tomography is an emerging medical imaging research area that has rarely been used for anything besides human tissue imaging. The system described in this thesis was specifically designed for in vivo measurement of tree trunks and is one of the first of its kind. The system forms an image by using frequency domain sampling over a wide bandwidth (1-5 GHz) and a ring of antennas. Microstrip monopole antennas specifically designed for use in microwave tomography systems are used and their design is presented. The system also uses a microwave switch matrix to switch between active pairs of antennas. The design of this switch matrix and the controlling software is also presented. Lastly, this thesis discusses the use of time reversal image reconstruction and the signal processing involved to create an image. Measured results of simple targets and preliminary measurements of tree trunk samples are both included.
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