Design of Low Loss Ka-Band SPDT Switch Based on AlGaN/GaN HEMT Technology

A low loss Ka-band single pole double throw (SPDT) switch MMIC, which can be used in millimeter-wave phased array T/R modules, has been designed and fabricated on AlGaN/GaN HEMT technology. The dimensions of GaN HEMT have been optimized to get best RF performances. The off-capacitance of the optimized GaN HEMT is 160 fF/mm and the on-state resistance 1.77 Ω-mm, showing a superior figure-ofmerit of 283 fs. With the optimized GaN HEMTs, a SPDT switch has been designed. On-wafer measured results show a 0.7dB insertion loss and 20dB isolation for the fabricated GaN SPDT switch. An input P0.1dB of 41dBm has been demonstrated through large signal characterization. The area of the SPDT switch is 2.45 mm× 1.15 mm.