Design of 39-GHz Up- and Down-Conversion Mixers for 5G mmWave TDD Applications

This article presents fully integrated 39-GHz bidirectional up- and down-conversion mixers for 5G millimeter-wave (mmWave) applications. Fabricated in a 65-nm CMOS process with a 1.2-V supply voltage, the up- and down-conversion mixers consume 39 and 43 mW, respectively. For 5G time-division duplexing (TDD) operation, intermediate-frequency (IF)/local-oscillator (LO)/radio-frequency (RF) T/R switches are introduced. For better isolation and low insertion loss between the up- and down-conversion mixer, a series-shunt single-pole double-throw (SPDT) structure and an equivalent lumped λ/4 transmission line are proposed for IF and RF T/R switches, respectively. To realize compact area and wide bandwidth, a transformer-based matching network is adopted in this design. Targeting multi-channel phased array applications, the measurement result shows that the up-conversion mixer achieves a 2.5-dB peak conversion gain with 6.5 GHz 3-dB bandwidth. Including the insertion loss of the switch and IF signal routing, at the maximum gain of 36.5 GHz, the up-conversion mixer achieves an output 1-dB gain compression point (OP1dB) of 2.5 dBm. Furthermore, the down-conversion mixer achieves a 5-dB peak conversion gain with a 9.7-GHz 3-dB bandwidth.