A high efficiency and multi-band/multi-mode power amplifier using a distributed second harmonic termination

This paper proposes a new broadband saturated power amplifier (SPA) with a distributed second harmonic termination supporting multi-band/multi-mode operation. The proposed network is composed of a fundamental matching circuit and multiple second harmonic termination circuits. Due to the multiple harmonic terminations, the proposed PA improves the frequency range where the PA can achieve a high efficiency. The proposed PA is fabricated using a 45 W Cree CGH40045 GaN HEMT. Drain efficiencies of greater than 60% (average 66%) are achieved between about 1.8 GHz and 2.3 GHz (500 MHz bandwidth). When driven with long term evolution (LTE) and two carrier wideband code division multiple access (WCDMA) signals at DCS1800, PCS1900, and WCDMA bands, the linearity specifications of the corresponding standards are satisfied using the digital predistortion linearization technique, and it attains an efficiency of greater than 30%.