Dual-Band High-Efficiency Power Amplifier With Adjustable Transmission Zero

A methodology for designing a dual-band (DB) high-efficiency power amplifier (PA) with adjustable transmission zero (TZ) is proposed in this brief. For achieving a compact topology, the circuit for constructing the adjustable TZ is merged into the output matching network (OMN), and an open stub is shared by the harmonic control network (HCN) and the OMN. For verifying the proposed design method and structure, a prototype operating at 2.1 and 3.5 GHz is designed. The adjustability of the TZ is analyzed, and the frequency range of the TZ is between 2.3 and 3.2 GHz. For verification, the TZ is set to be 2.4 GHz and the DB PA is fabricated and measured. The result shows that the PA achieves the maximum power-added efficiency (PAE) of 68.5% and 64.8% with the output power of 41.0 and 40.4 dBm at 2.1 and 3.5 GHz, respectively. Moreover, the power gain at the TZ of 2.4 GHz is −26.9 dB, which shows a good suppression effect. Therefore, the proposed PA has a good application prospect in wireless communication systems.