Dynamic Range of an Active Radio Sensor for Bias-Switched Arrays for Microwave Tissue Imaging

A prototype of an active radio sensor is fabricated and tested on breast-tissue phantoms in order to establish achievable sensitivity and dynamic range. The sensor is intended as an element in large arrays for microwave tissue imaging that multiplex several hundred sensors through bias switching. It consists of a printed slot antenna, a low-noise amplifier and a mixer. The sensor area that comes into contact with the tissue is largely determined by the antenna area, which is as small as 12 by 12 mm. The operating bandwidth is from 3 GHz to 7.5 GHz and the output intermediate frequency is 30 MHz. The achievable dynamic range of the sensor is measured to be 109 dB when the resolution bandwidth is 1 kHz.