A 19.1-dBm-Linear 2-20 GHz N-path Down-converter in HRL 40-nm GaN for Resilient Receivers

This paper demonstrates the potential for GaN Npath down-conversion mixers to operate linearly in the presence of 19.1 dBm in-band interference and >25 dBm out-of-band. We measured 4-10 dB NF across 2-20 GHz for this LNA-less 4-phase active-mixer receiver front-end including degradations due to non-negligible amplitude/phase imbalance introduced by the off-chip hybrid and balun modules used to generate quadrature gate drive from a 16 dBm single-ended source. The mixer consumes 25 mW with a 2.5 V drain bias to ensure low-loss hard-switching under sinusoidal drive (as opposed to non-overlapping digital pulses or resonant pseudo-pulses used in prior art N-path downconverters) delivering a 10 dB improvement in SFDR over 9.3x greater fractional bandwidth compared to previously reported GaN N-path down-converters. With 200 MHz instantaneous BW, the receiver front-end achieves a maximum 98 dB dynamic range under 3.5 dB NF desensitization caused by 15 dBm in-band interference. To quantify the utility of receivers for operating in the presence of high-power, co-site emitters we define a new FoM for emitter resilience that considers receiver sensitivity, power handling, and frequency coverage.