Dual-Band Continuous Class-F-1 Power Amplifier With Second-Harmonic Suppression for Harmonic Radar Systems

In this study, a highly efficient harmonic suppressed dual-band power amplifier (PA) for harmonic radar systems is proposed. The proposed PA incorporates a harmonic-controlled dual-band matching network (HCDMN) comprising lambda/4 open stubs at the second-harmonic frequencies and series transmission lines. The HCDMN can effectively suppress unwanted second-harmonic signals and control the fundamental and second harmonic impedances to operate in continuous class-F-1 mode at two operating frequencies. The implemented PA has dimensions of 75.3 mm x 54.9 mm. Measurement results demonstrate that the PA achieves an exceptional performance, with peak drain efficiencies (DEs) of 81.5 and 71.8 %, saturated output powers of 40.3 and 41.9 dBm, and second harmonic levels of -75.6 and -49.4 dBc at 2.3 and 3.35 GHz, respectively. Furthermore, the DEs remain above 65 % in the two frequency bands of 2.2-2.5 and 3.3-3.45 GHz.