High-Sensitivity CMOS Super-Regenerative Receiver with Quench-Controlled High- $Q$ Metamaterial Resonator for Millimeter-Wave Imaging at 96 and 135 GHz

High-sensitivity super-regenerative receivers (SRXs) are demonstrated at 96 and 135 GHz, respectively, in this paper. They are based on high-Q quench-controlled metamaterial resonators with a differential transmission line loaded with a split-ring resonator (DTL-SRR) and a differential transmission line loaded with a complementary split-ring resonator (DTL-CSRR) in 65-nm CMOS. High-Q oscillatory amplifications are established by the sharp stopband introduced by metamaterial resonators. As such, high detection sensitivity is achieved for SRXs at millimeter-wave regions. The fabricated 96-GHz DTL-CSRR-based SRX has a compact core chip area of 0.014 mm² with measured power consumption of 2.8 mW, sensitivity of -79 dBm, noise figure (NF) of 8.5 dB, and noise equivalent power (NEP) of 0.67 fW/√(Hz). The fabricated 135-GHz DTL-SRR-based SRX has a compact core chip area of 0.0085 mm² with measured power consumption of 6.2 mW, sensitivity of -76.8 dBm, NF of 9.7 dB, and NEP of 0.9 fW/√(Hz). Compared to the conventional SRX with an LC-tank-based resonator at similar frequencies, the proposed SRXs have 2.8~4 dB sensitivity improvement and 60% smaller area. The integrated SRXs are also demonstrated for the imaging applications.