Widely Tunable High-Efficiency Power Amplifier With Ultra-Narrow Instantaneous Bandwidth

Kenle Chen, Birck Nanotechnology Center, Purdue University
Xiaoguang Liu, Birck Nanotechnology Center, Purdue University
Dimitrios Peroulis, Birck Nanotechnology Center, Purdue University

Abstract

This paper reports the first power amplifier (PA) that simultaneously achieves a very narrow instantaneous bandwidth (2%) while being tunable over a 38.5% frequency range (2.1-3.1 GHz) with a measured 50%-60% efficiency in the entire band. Such PAs are in great demand for realizing all-digital burst-mode transmitters that are expected to become critical for the future generation of wireless communication systems. Unlike state-of-the-art planar PAs that cannot simultaneously achieve a narrow bandwidth and high efficiency, the presented PA employs a widely tunable high-Q (Q > 300 over the tuning range) cavity resonator as the output matching network. Furthermore, the tunable multiband matching is performed for both the fundamental frequency and the second harmonic to ensure a high efficiency. The measured PA is implemented with a Cree GaN transistor, and it delivers an output power of >= 36 dBm at a gain of >= 10 dB. Two-tone testing is further conducted, indicating a good linearity of this PA with an output third-order intercept point greater than 48 dBm over the entire band. This design demonstrates, for the first time, that multiband burst-mode transmitters can be potentially built with widely tunable high-efficiency narrowband PAs.

Discipline(s)

Nanoscience and Nanotechnology