A $K$ -Band SiGe Superregenerative Amplifier for FMCW Radar Active Reflector Applications

A K-band integrated superregenerative amplifier (SRA) in a 130-nm SiGe BiCMOS technology is designed and characterized. The circuit is based on a novel stacked transistor differential cross-coupled oscillator topology, with a controllable tail current for quenching the oscillations. The fabricated integrated circuit occupies an area of 0.63 mm
²
, and operates at the free-running center frequency of 25.3 GHz. Characterization results show circuit operation from a minimum input power level required for a phase coherent output as -110 dBm, and the input power level corresponding to the linear to logarithmic mode transition of -85 dBm, the lowest reported for K-band integrated logarithmic mode SRAs to date to the knowledge of the authors. The measured output power is +7.8 dBm into a 100 Ω differential load. The power consumption of the circuit is 110 mW with no quench signal applied, and 38 mW with 30% duty cycle quenching. The quench waveform designed for the reported measurement result is also discussed.