Integrated-antenna push-pull power amplifiers

TLDR

The paper applies the integrated‑antenna concept to push‑pull power amplifiers. The architecture uses the antenna as an out‑of‑phase power combiner and tuned load for higher harmonics, implemented in narrow‑band and broadband push‑pull amplifiers with dual‑feed patch and slot antennas. The integrated‑antenna push‑pull amplifiers achieve high efficiency, with measured PAEs of 55 % at 2.5 GHz, 63 % peak in a broadband design, and 48 % under CDMA modulation while maintaining an adjacent‑channel power ratio better than –42 dBe.

Abstract

In this paper, the integrated-antenna concept is applied to push-pull power amplifiers (PAs). In this approach, the antenna serves as an out-of-phase power combiner and tuned load for higher harmonics. This new architecture effectively has a near-zero loss output hybrid, and results in a high-efficiency PA. The first example is a narrow-band push-pull amplifier integrated with a dual-feed patch antenna. At an operating frequency of 2.5 GHz, a maximum measured power-added efficiency (PAE) of 55% is achieved. The second example is a broadband push-pull amplifier integrated with a dual-feed slot antenna amplifier operating at 2.46 GHz which has a peak PAE of 63%, and PAE better than 55% in an 8% bandwidth. Additionally, 48% PAE is achieved with code-division multiple-access modulation and adjacent-channel power ratio better than -42 dBe at a 1.25-MHz offset.