High-efficient harmonic-tuned power amplifier with more than an octave bandwidth

A design approach of high-efficient power amplifiers with more than an octave bandwidth is proposed in this letter. The load-pull method is employed at both fundamental and harmonic frequencies, and the simplified real frequency technique (SRFT) algorithm is used to design and synthesize the PA matching networks. Experimental results show that the fabricated PA operates from 525 MHz to 1325MHz, with drain efficiency over 70% and output higher than 39dBm. Digital predistortion is applied to the PA and the adjacent channel power ratio (ACPR) is improved to more than −40 dBc.