Broadband class-E power amplifier with high cold output impedance suitable for load modulated dual branch amplifiers

The paper presents a design of a broadband high-efficiency class-E power amplifier (PA) for the advanced efficiency enhancement architectures applications. The design approach is based on presenting very high output reflection coefficient for a class E amplifier over broadband frequencies. An infinite reflection coefficient at load over the broadband frequency range enhances the application of class-E PAs as peaking amplifier in advanced efficiency enhancement architectures like Doherty, delta sigma etc. The proposed approach is validated using a Cree 6 W GaN prototype for a frequency band between 1.8-2.7 GHz. The prototype outputs more than 38 dBm output power with the drain efficiency higher than 55% over 40% of the fraction bandwidth. The drain voltage sweep of the fabricated PA shows that it can be also be employed in load modulated dual branch amplifiers and envelop tracking transmitter structures.