A Compact Low-Loss High-Reliability Antenna T/R Switch Embedded in Power Combiner for 60-GHz Fully Differential PA and LNA

This letter proposes an antenna transmit/receive (T/R) switch embedded in the power combiner of the two-way power amplifier (PA) and realizes a 60-GHz fully differential T/R front end (FE). Compared with the traditional standalone single-pole-double-throw (SPDT) switch, only one switch transistor is needed in the PA power combiner and reused for both transmit (TX) and receive (RX) modes, thereby significantly reducing the chip area and the insertion loss. With careful codesign of the switch with the PA and low-noise amplifier (LNA) matching networks, the insertion loss introduced by the switch and the loading effect could be reduced to 0.5 and 1 dB in the TX and RX modes, respectively. Fabricated in a 65-nm CMOS process, the PA achieves a power gain, OP<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\mathrm {1\, dB}}$ </tex-math></inline-formula>, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${P} _{\mathrm {sat}}$ </tex-math></inline-formula>, and PAEmax of 25 dB, 11 dBm, 16 dBm, and 16%, respectively. Benefitting from the low loss of the switch, the LNA attains a peak gain and noise figure (NF) of 25 and 6.4 dB, respectively.