A 26/28/39-GHz Reconfigurable Phased-Array Receiver Front-End With Built-In Calibration Technique for 5G New Radio

This article presents a reconfigurable phased-array receiver (RX) front-end supporting multiple fifth-generation (5G) new radio (NR) frequency range 2 bands at 26/28/39 GHz. A reconfigurable frequency downconverter (RFDC) with two operating modes is proposed to cover both K -and Ka -bands. Distinct from conventional wideband or multi-band structures, the proposed one does not need wide/multiple local-oscillator (LO) or intermediate-frequency (IF) bands. Cooperating with an appropriate LO-and IF-frequency scheme, the reconfigurable architecture moves image interferences out of a passband of RF channels in both the modes, and thus an excellent image rejection is achieved. A compact and fast built-in calibration (BIC) circuit, which is based on an adjacent-channel envelope comparison technique, is also developed to cope with potential phase and gain errors in each RF channel. The phased-array RX is demonstrated using a 65-nm CMOS technology. Measurement results show that the RX successfully covers both 24-30-GHz and 36-40-GHz bands, while only requiring an LO range of 9.5-12.5 GHz with 5-GHz IF. The tested gains, noise figure (NF), and input 1-dB compression point are 16.2/16.9 dB, 5.9/6.2 dB, and - 30.7/ - 31.4 dBm at 26/28 GHz when it functions in a differential mode, while the corresponding results are measured as 15.3 dB, 6.6 dB, and - 32.8 dBm at 39 GHz in a common mode. Tested image-rejection ratios (IRRs) are > 43 dB in both the operating modes. The BIC circuits' functionality is also tested. It reduces root-mean-square (rms) gain and phase errors of the RX by 0.12-0.28 dB and 2.3^{\circ} - 4.5^{\circ} , respectively. Therefore, the RX's tested beamforming performance is greatly improved, compared with the one without calibration.