38-GHz CMOS Linearized Receiver With IM3 Suppression, P1 dB/IP3/RR3 Enhancements, and Mitigation of QAM Constellation Diagram Distortion in 5G MMW Systems

• Published in: IEEE transactions on microwave theory and techniques 2020-07, Vol.68 (7), p.2779-2795
• Main Authors: Chen, Chun-Nien, Chen, Ying, Wang, Yunshan, Kuo, Tai-Yu, Wang, Huei
• Format: Article
• Language: English
• Subjects: 5G millimeter wave (5G MMW); 5G mobile communication; 65-nm CMOS; Built-in linearizer; cold-bias; constellation diagram (CD); Demodulation; Gain; I/Q Rx; Iron; Linearity; Phased arrays; Quadrature amplitude modulation; quadrature amplitude modulation (QAM); third-order intermodulation (IM3)
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/TMTT.2020.2981461

This article proposes a 35-39-GHz high linearity in-phase and quadrature components receiver (I/Q Rx) using a 65-nm CMOS for quadrature amplitude modulation (QAM) carrier demodulation in 5G millimeter wave (MMW) systems. An innovative cold-bias transistor passive mixer core with low local oscillator (LO) power is proposed. Built-in MMW linearizers are adopted in the low-noise amplifier (LNA) and downconverter to improve the linearity with significant third-order intermodulation (IM3) power suppression in a wide RF/IF power range for QAM demodulation. According to the Rx measurement at 38 GHz, it exhibits the −13 dBm IP 1dB /0.8 dBm OP 1dB and 2 dBm IIP3/16.8 dBm OIP3 with the highest IM3 reduction of 31 dB. The maximum output (IF) power with a third-harmonic rejection ratio (RR3) lower than −40/−30 dBc is −4.7/−2 dBm, which exhibits a superior IM3 suppression capability at high power level. Moreover, QAM constellation diagram (CD) distortions due to IM3 interferences of the Rx in high RF/IF power are investigated. Experiments verify that distorted CDs are recovered by using the proposed linearizers. To the best of the authors' knowledge, the proposed Rx exhibits the highest IF linear power with RR3 ≤ −30 dBc compared to the published Rxs/downconverters and is the first MMW linearized Rx that demonstrates an ability to mitigate QAM CD distortions.