A W-Band GaN MMIC Single-Chip T/R Front End

A single-chip transmit-receive (T/R) front end covering (75-110) GHz is implemented in a 40-nm GaN on SiC HEMT process. The transmit path consists of a balanced power amplifier (PA) with three-stage unit PAs and an additional single-HEMT driver to achieve above 17-dB small-signal gain over the range and over 15 dB of large-signal gain across 75-108 GHz. The receive path consists of a three-stage low-noise amplifier (LNA) with a small-signal gain of 16-22 dB and de-embedded calculated noise figure (NF) of 4-6.5 dB across the range. A single pole double throw (SPDT) shunt switch with an insertion loss of 1-1.5 dB and an isolation between 15 and 20 dB across the band selects the transmit or receive paths in this half-duplex front end and does not show compression in transmit mode. In transmit mode, the front end measures > 25 dBm over 75-110 GHz with a measured maximum of 29 dBm of output power at 92 GHz. In receive mode, the front end shows an NF of 5.2-7.8 dB with a gain of 16-22 dB. The demonstrated output power in transmit and NF in receive modes, with sufficient isolation, makes this single-die T/R component suitable for communications, imaging, and sensing.