Cylindrical geometry: a further step in active microwave tomography

A prototype imaging system for active microwave tomography using cylindrical geometry has been developed, making it possible to obtain images of the dielectric properties of biological targets at 2.45 GHz. This configuration allows a fast exploration of body slices placed along the array axis, in a way similar to that of present X-ray scanners. The electromagnetic compatibility (EMC) of this approach is critical because the strongly attenuated received fields are measured on the same array which is being used to emit a high-level illuminating signal. Therefore, carefully designed high-frequency architectures and detection techniques are necessary. The system requires no mechanical movements to illuminate the body from multiple directions (views) and measure the scattered fields. In this way, a complete data set consisting of 64 views is acquired in 3 s using low-power illumination. The system is described, and images obtained with biological phantoms and actual bodies are presented