A 10--72 GHz SDR Receiver With Compact and Low-Phase-Noise LO Frequency Quintupler

This article presents a wideband receiver (RX) operating in 10–72 GHz with multiprotocol coverage, which integrates the inductor-less local oscillator (LO) frequency quintupler for down-mixing. In the LO generator, phase interpolators (PIs) are implemented to obtain five-phase pulses. Then compact edge-combining switched-capacitor (SC) based frequency quintuple techniques are proposed to output LOs ranging from 10 to 40GHz while operating within the 2–8 GHz frequency range. The lower input frequency brings lower driving difficulty, higher I/Q precision, and better phase noise performance. Therefore, based on the LOs orthogonality accuracy and IQ calibration, the baseband phase shifter (PS) with lower power and die area consumptions is applied in the receiver. For the 40–72 GHz channel, the RF signals are down-mixed two times with the same LO frequency to reduce the quintupled LO frequency to fRF/2. By folding the image band to DC during the first down-mixing, an image rejection ratio (IRR) exceeding 100 dB is achieved through the input-matching transformer of LNA, thus eliminating image interference and flicker noise introduction. Fabricated in 40-nm CMOS technology, the proposed RX features a core area of 0.9mm2, a conversion gain of over 45 dB, an output IP3 of over 19.7 dBm, and the noise figures (NFs) lower than 6.1, 6.9, and 8.7 dB in the 10–18 GHz, 18–40 GHz, and 40–72 GHz bands, respectively.