An Ultra-Compact Switchless Bidirectional PA-LNA with 8-Shaped Transformer-Based Inter-stage Matching Networks for W-Band Applications

This paper presents an ultra-compact wideband bidirectional switchless PA-LNA for W-band wireless applications. The proposed PA-LNA adopts a single-signal-path topology, integrating highly efficient 8-shaped transformers and tri-coil baluns to minimize electromagnetic cross-coupling, reduce insertion loss, and enhance linearity in a compact size. The PALNA prototype is fabricated in 40nm CMOS LP process. It achieves a 3-dB bandwidth from 79 GHz to 92 GHz, a saturated output power ($P_{\text {sat }}$) of 13.7 dBm, an output 1-dB compression point (OP1dB) of 8.7 dBm, and a maximum power-added efficiency (PAE) of 9.5% in PA mode. In LNA mode, it exhibits a 3-dB bandwidth from 86 GHz to 98 GHz and a minimum noise figure (NF) of 8.2 dB, all within a compact core area of only $0.1 \mathrm{~mm}^{2}$.