Modular Design and Characterization of a Reconfigurable Sequential Power Amplifier

This paper demonstrates a modular design approach for a sequential power amplifier (SPA) with reconfigurable output power back-off (OPBO) characteristics. The proposed dual-input SPA consists of a main amplifier (10W), a peaking amplifier (25W), and a 6.5 dB coupler. This SPA is implemented by using two off-the-shelf PAs both with overlapping bandwidths between 3.3 and 3.7 GHz. When combined together the SPA presents the same operational bandwidth but with additional enhanced backoff efficiency. This SPA achieves a peak drain efficiency of 51% at 9 dB back-off, and 36% at maximum output power at 3.5 GHz while maintaining the same bandwidth of the two constituent PAs. The resulting SPA performance is competitive with other state-of-art Doherty PAs and SPAs.