Fine resolution (1.35 cm) ultra wideband radar tomographic imaging using an 8.5 GHz vector network analyzer and a rotating pedestal

This paper describes an ultra wideband (UWB) radar tomographic imaging system based on a vector network analyzer (VNA) and a rotating pedestal. The Agilent E5071B VNA was used to capture measurements over a wide frequency range from 1.5GHz-8.5GHz in a radar mode by attaching horn antennas to each of the ports and pointing them at objects located on a rotatable turntable. The 3dB range resolution obtained with the 7GHz processed bandwidth was approximately 2.9cm. After tomographic processing of measurements captured over the full 360 degrees of platform rotation, the 3dB resolution obtained in the final image was approximately 1.35 cm. A calibration scheme was devised to compensate for the frequency response of the antennas providing high quality images. Measurements and images obtained from several objects are presented including a thin 2mm wire, a household plug and a model of a handgun.