A Low-Power, Subharmonic Super-Regenerative Receiver toward a Massive Multichannel FMCW Radar Close to Cut-Off Frequency

This paper reports for the first time on an entirely new subharmonic super-regenerative receiver (SRR) concept. Unlike in conventional SRRs, the local oscillator signal is additionally used for non-linear downconversion, enabling phase-coherent amplification. An experimental concept verification is done with a 24 GHz FMCW radar transceiver implemented using planar microstrip technology. It is shown that the subharmonic SRR down-conversion allows to significantly increase the maximum operating frequency and bandwidth. In addition, the LO power requirements are considerably reduced compared to what is typically needed in passive mixer approaches. Operated with a sinusoidal quench signal, the fabricated SRR achieves a gain greater than 60 dB with a power consumption of only 24 mW. It is explained that the concept allows also for operation near the semiconductor cutoff frequency. Due to this, and because of its simplicity, this novel concept is especially suited for scaling to integrated circuits with a high number of receive channels at very high, several 100 GHz, carrier frequencies.