A Phased-Array Receiver Front-End Using a Compact High Off-Impedance T/R Switch for n257/n258/n261 5G FR2 Cellular

This paper presents a low-power and compact phased-array receiver (RX) front-end (FE) in 28nm CMOS FD-SOI for n257/n258/n261 5G FR2 cellular applications. A compact high off-impedance SPST T/R switch with an embedded 2-bit 18dB variable attenuator is proposed to minimize TX degradation while maintaining a low insertion loss with additional gain control for RX. With the T/R switch and PA output matching network (OMN), the TX/RX interface is co-optimized for TX output power and RX NF. Over the frequency band of 24.25-29.5GHz the RXFE achieves measured RX NF of 4.4-5.6dB with similar to 41dB gain control range and similar to 35dB IP1dB range. The RXFE occupies a small die area of 0.14mm(2). The RX operation consumes only 13.4mW and 4.7mW DC power in sensitivity mode and low-gain/high-linearity mode respectively.