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

In this article, the feeding techniques for high-power and high-efficiency E-band (60–90GHz) power amplifiers (PAs) that employ high-electron-mobility transistors (HEMTs) with a gate periphery of $8 \times 45 \mu \mathrm{m}$ are investigated. To enhance the performance of the HEMTs with extended periphery, a symmetrical gate feeder and a low-impedance drain feeder line are proposed for the input and output matching networks, respectively. A wideband three stage PA is demonstrated with an $8 \times 45 \mu \mathrm{m}$ HEMT at the final stage, utilizing IAF GaN 100nm technology. The measured PA delivers an output power of 28.7dBm associated with a power-added-efficiency (PAE) of 25.4% at 76GHz while maintaining a PAE above 20% from 70 to 80GHz. Moreover, the PA exhibits a small-signal gain of more than 19.5dB within the 49-79GHz range, featuring a 3-dB bandwidth of 30GHz. To the best of the authors’ knowledge, this is the first PA to demonstrate PAE exceeding 20% and covering the majority (70–80GHz) of the Satcom E-band.