Integrated-antenna push-pull power amplifiers

In this paper, the integrated-antenna concept is applied to push-pull power amplifiers (PA's). 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 broad-band push-pull amplifier integrated with a dual-feed slot antenna amplifier operating at 2.46 GHz has a peak PAE of 63%, and PAE is 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 dBc at a 1.25-MHz offset.