An Automatic Gain and Offset Control Circuit for DC-Coupled Continuous-Wave Radar Systems

This publication addresses the problem of offsets and offset drifts in continuous-wave radar systems and presents a compensation circuit as hardware solution. In the first part, the sources of static offsets in the baseband voltages are identified and quantified by using an exemplary six-port based radar system. To solve the problem, an offset control circuit is introduced and the benefit, a better use of the analog-to-digital-converter's inputs leading to a reduction of quantization noise, is derived in theory and validated by measurement. The compensation circuit is digitally controlled by a microcontroller and can be used in any six-port or mixer-based radar system.