Broadband high-power W-band amplifier MMICs based on stacked-HEMT unit cells

This paper reports on a broadband high-power amplifier (HPA) millimeter-wave integrated circuit (MMIC) covering the extended W-band (65-125 GHz). The MMIC is based on the Fraunhofer IAF 50-nm gate-length metamorphic high electron-mobility transistor (mHEMT) technology. The HPA consists of two parallelized unit amplifiers. Each unit amplifier (UA) utilizes four stacked-HEMT unit power cells (UPCs) and fourway power combiners at the input and output. The UPCs stackfour transistors with a gate width of 4 × 40 mm per HEMT.The UA achieves an average small-signal gain of 19.4 dB andan average saturated output power of 21.6 dBm at least from 70 to 110 GHz. The HPA yields an average small-signal gain of 16.8 dB and an average saturated output power of 22.5 dBmat least from 68 to 110 GHz. A peak output power of 24.1 dBmis achieved at an operating frequency of 75 GHz.