A Broadband Transmit-Receive Front-End with Three-λ/4-line-based T/R Switch for 5G FR2 Bands

This paper presents a broadband transmit-receive (T/R) front-end in 65nm CMOS for fifth-generation (5G) FR2 application. A three- $\lambda / 4$-line-based T/R switch composed of lumped-element impedance inverters is proposed to achieve wideband output power for PA and wideband NF performance for LNA simultaneously. The matching networks of the PA and the LNA are co-designed with the T/R switch to reduce the insertion loss and chip area. In the transmit-mode, the implemented T/R front-end achieves a fractional bandwidth of 65% from 23.3 to 45.8 GHz and the saturated output power of 15-16 dBm over 28-44 GHz. In the receive-mode, the T/R frontend achieves 3 dB bandwidth of 14.7 GHz from 23.6 to 38.3 GHz with a minimum NF of 4.61 dB. The core area of the T/R frontend is $0.19 \mathrm{~mm}^{2}$.