E-band Downlink GaN PA with a Homogeneous Output Power of 2.7W and a Peak PAE of 32.3%

A highly homogeneous, high efficiency, multi-watt output power E-band downlink (71–76GHz) Gallium Nitride (GaN) power amplifier (PA) is presented in this article. The 4-stage PA has been measured with an output power of $33.5 \pm 0.8$ dBm $( 2.28 \pm 0.42\mathrm{W})$ across the 68--76GHz frequency range. The peak power-added-efficiency (PAE) of 32.3% is measured at 69GHz, with an associated output power of 34.3dBm (2.7W) and a power gain of 22.3dB. The peak PAE variation across the 31 working cells (out of 37 cells) measured on-wafer is less than 2.5%-points, which demonstrates the design's homogeneity. These results are made possible by excellent in-house wafer processing, utilizing the new microstrip line (MSL) transistor models, and implementing the core matching networks with two-section transmission lines, which are also designed to have a low insertion loss. To the best of the authors' knowledge, the peak PAE and power gain reported in this work are the highest for a multi-watt level PA published in the literature at E-band (60–90GHz).