An Ultra-compact Bidirectional Ka-Band Front-End Module with 4.0-dB NF and 13.5-dBm OP1dB

This paper presents an ultra-compact bidirectional Ka-band front-end module (FEM) by using foldedtransformer-based matching networks and transformer-based transmit/receive switches (TRSWs). This design uses 8-shaped folded transformer technique to cancel the magnetic coupling enabling transmit path can be folded to the receive path and the matching networks of power amplifier (PA) and low noise amplifier (LNA) can share a same footprint, which improves the area efficiency greatly with negligible performance penalty. Furthermore, the TRSW, which is composed of a three-inductor coupled resonator, realizes the functions of the balun, input matching network of the receiver (RX), and output matching network of the transmitter (TX) within only an inductor footprint. Implemented in 65-nm CMOS process, the FEM achieves 26 dB peak gain with a 4.0 dB minimum NF in RX mode, while it achieves peak gain of 26.5 dB and 15.1 dBm saturated output power (Psat) in TX mode in Ka-band. The core size of this proposed design is only 0.1 mm2 that is only 20% to 50% of the size occupied in prior works.