A Stabilized Broadband Correlator for Medical Microwave Thermography

A stabilized broadband summing microwave correlator is presented that has particular application to medical microwave thermography. A dual IF is employed to minimize long-term drifts resulting from antenna-source mismatch, RF amplifier gain drifts, and changes in uncorrelated background radiation. The correlation of the source is generated by means of a digital line stretcher, rather than antenna-source movement. Preliminary measurements using a low-temperature thermal source in air are presented.