An Ultra-Compact W-band Front-End with Coupled-Line-Based Matching Network Reused T/R Switch Achieving 13.4-dBm P_satand <2-dB Switch Loss in 65-nm CMOS Technology

This letter presents a W-band front-end (FE) with integrated coupled-line-based matching network reused transmit/receive (T/R) switch in 65-nm CMOS technology. The proposed T/R switch is mainly composed of three coupled-lines and also functions as the balun, source matching, and gm-boosting network for LNA as well as load matching network for PA simultaneously in an ultra-compact way. The coupled-line-based T/R switch eliminates the lossy transistor switch in the signal path and the additional matching networks of LNA and PA, which greatly reduces the insertion loss (IL) and chip area. The T/R switch, LNA, and PA are co-designed to achieve optimal overall FE performance. Measurement results show that the IL of the proposed T/R switch introduced in TX/RX mode is less than 1.65/2.0 dB. Benefitting from the low IL, the FE achieves a maximum gain of 27.12 dB while demonstrating an 8.7 dB minimum noise figure in the RX mode. The FE also achieves maximum P_{\mathrm{ sat}} /OP1dB of 13.43/9.8 dBm with 15.4%/7.2% PAEpeak / OP1dB in the TX mode. The core area of the FE is only 0.5 mm \times 0.6 mm.