X-band high-power HEMT SPDT switch with selectively anodised aluminium substrate

A high-power HEMT single-pole double-throw (SPDT) switch is introduced, based on a multichip module structure with a selectively anodised aluminium substrate. The proposed high-power SPDT switch uses thick anodised aluminium (Al₂O₃) layers and bare high-power HEMTs directly mounted on an aluminium substrate for an effective heatsink and high electrical isolation. A 4.4 × 3.1 mm compact highpower SPDT switch for X-band phased array applications is demonstrated. The fabricated X-band SPDT switch has a measured insertion loss of less than 1.3 dB and an isolation of 20.3 dB. In particular, the X-band switch exhibits an on-state power-handling capability that exceeds 35.5 dBm at a compression point of 1 dB. The experimental results suggest that the developed hybrid IC technology, which is based on selectively anodised aluminium, can be applied to high-power X-band SPDT switch applications.