Switched sensor array for near-field microwave imaging of tissue

This paper describes the design of an electronically-switched active antenna array for near-field microwave imaging of tissue in the range of 6 to 8 GHz. Each antenna element connects directly to a dedicated radio front-end, whose intermediate frequency output is fed to a common port for digital data processing. In this way, the difficulties of designing reproducible microwave switching and feeding networks are avoided. Within each front-end, switched-bias low-noise amplifiers are used to maximize the difference in received power between the on and off states of the imaging sensors, thereby enhancing the dynamic range of the measurement.