Investigating Feeding Techniques for High-power and High-efficiency E-band Power Amplifiers

In this article, the feeding for high-power and high-efficiency E-band (60-90 GHz) power amplifiers (PAs) that employ high-electron-mobility transistors (HEMTs) with a gate periphery of 8x45 µm are investigated. To enhance the performance of the HEMTs with extended periphery, a symmetrical gate feeder and low-impendance drain feeder line are proposed for the input and output ,atching networks, respectively. A wideband three stage PA is demonstrated with an 8x45 µm HEMT at the final stage, utilizing IAF GaN 100nm technology. The measured PA delivers an outpot power of 28.7 dBm associated with a power-added-efficiency (PAE) of 25.4% at 76 GHz while maintaining a PAE above 20% from 70 to 80 GHz. Moreover, the PA exhibits a small-signal gain of more than 19.5 dB within the 49-79 GHz range, featuring a 3-dB bandwidth of 30 GHz. To the best of the authors' knowledge, this is the first PA to demonstrate PAE exceeding 20% and covering the majority (70-80 GHz) of the Satcom E-band.