W-band SPDT switches in planar and tri-gate 100-nm gate-length GaN-HEMT technology

This paper reports on W-band (75 to 110 GHz) single-pole double-throw (SPDT) switch millimeter-wave integrated circuits (MMICs) based on a planar and a tri-gate 100-nm gate-length GaN high-electron-mobility transistor (HEMT) technology. The SPDT switches utilize the well-established quarter-wave stub topology with shunt transistors. For an improved wideband performance, an optimized layout approach is used that connects the shorted stub for the compensation of the capacitance of a shunt transistor at the center of the transistor. The presented SPDT switch MMIC demonstrates for both technology versions a measured average insertion loss of 1.3 dB over the entire W-band with a peak insertion loss of 1.2 and 1.1 dB in the center of the W-band for planar and tri-gate HEMTs, respectively. The one-dB bandwidth is for both MMICs almost an octave. For an input power of at least 25 dBm, both SPDT switches do not show an indication of compression.