Single- and Dual-Band Filtering Power Amplifiers

This paper presents single-and dual-band filtering power amplifiers (FPA). In single-band FPA, a bandpass filter (BPF) using discriminating coupling is proposed to be utilized as the output matching network (OMN). By analyzing coupling matrix of BPF, impedances of the OMN at fundamental mode and harmonic are controlled independently. In dual-band FPA, a dual-band filtering network synthesis technique is proposed. It includes two steps: building impedance transformation network (ITN) with transmission zeros pair (TZP) to generate dual-band filtering performance and utilizing synthesis technique to obtain the structure parameters by making the fundamental and the second harmonics matched at the two passbands. For demonstration, a single-band FPA with wide bandwidth of 31.1% is implemented and measured. Also, the dual-band FPA exhibits both high bandpass selectivity and good PA performance with maximum power added efficiencies (PAEs) of 70.2% and 69.2% at 1.78 and 2.45 GHz, respectively.