A compact tri-band GaN voltage-mode class-D/S PA for future 0.8/1.8/2.6 GHz LTE picocell applications

This paper presents a compact tri-band voltage-mode class-S power amplifier module suitable for the LTE frequency bands of 0.8, 1.8 and 2.6 GHz. The demonstrator uses a broadband GaN voltage-mode PA MMIC and a hybrid SMD element tri-band filter introducing transmission zeros between the pass bands for improved isolation. Applying pulse-width modulated input signals the digital PA achieves a maximum output power of 5 W at 0.8 GHz, 2.2 W at 1.8 GHz, and 1.4 W at 2.6 GHz. Peak drain efficiency is 87%, 56% and 41% for 0.8 GHz, 1.8 GHz and 2.6 GHz, respectively. PAE values of 40% and a large-signal gain of 33 dB are reached.