A Linear High-Efficiency Distributed Power Amplifier Utilizing Class-AB and Inverse-Class-C Complementary Structure

This paper presents a wideband high-efficiency linear time-domain waveform-complementary distributed power amplifier (TDWC-DPA), with gain cells (GC) composed of deep Class-AB and inverse-Class-C structures. The proposed inverse-Class-C GC consists of N-type devices operating in the saturation region instead of in the cutoff region compared with conventional Class-C amplifiers. This allows the amplifier to conduct near the valleys of the input signal. This unique characteristic enables the inverse-Class-C GC to achieve an opposite conduction state compared to deep Class-AB amplifiers. Furthermore, distributed base-and collector-networks are deployed to combine deep Class-AB and inverse-Class-C GCs and form the standard sinusoidal signals with low harmonic content further through. The amplifier achieves enhanced in-phase superposition of fundamental waves with proper bias of the common base transistor. The fabricated TDWC-DPA achieves 41.8 dBc second harmonic suppression (HS) and 39.1 dBc third harmonic suppression respectively. With integrating 500 V output ESD protection, the single-ended TDWC-DPA achieves a $-$ 3-dB bandwidth from 2 to 14 GHz and a small signal gain of 20 dB. The maximum power-added efficiency (PAE) is 33.6%, the saturated output power is 19.4 dBm and the output 1 dB compression point (P $_{\mathrm{1dB}})$ is 19.2 dBm. The proposed TDWC-DPA achieves significantly enhanced linearity with maintaining a competitive efficiency in a wide frequency range and can support communication systems deploying high-order modulation formats.