From Device characterization to System Level Analysis of Dual Band PA Design

In this article, the design of a dual-band PA developed in SiGe HBT technology and its system level investigation are presented. Starting from an extensive nonlinear characterization at the device level, by which the optimum load conditions was inferred, an optimized amplifier capable to operate simultaneously at 2.45 and 3.5 GHz was designed. The designed amplifier exhibits in single-band mode operation 9.3 dBm and 13.4 dBm output power (1 dB compression point) at 2.45 GHz and 3.5 GHz, respectively. When working under simultaneous channel amplifications, an higher reduction of the 1 dB compression point at 3.5 GHz, compared with the one at 2.45 GHz, is observed; this reflects in a more significant degradations of system level performance such as the error vector magnitude. The investigation provided in this article and the conclusions suggest new concepts and possible new system architectures for the development of the next generation of multi-band transceiver front-end.