Co-Design of Class-F⁻¹ Microwave Amplifier and Bandpass Filtering Matching Network With Harmonics Control Functionality

This paper demonstrates the co-design of class-F⁻¹ microwave amplifier (MA) and bandpass filtering (BPF) matching network (MN) with harmonics control functionality (HCF). The proposed BPF MN can match arbitrary termination impedances (ATIs) to 50 Ω at fundamental frequency (f₀) and simultaneously control the second harmonic (2f₀) and third harmonic (3f₀) impedances to be open- and short-circuited, respectively. The BPF MN with HCF is realized with the alternative J/K inverters cascaded via quarter wavelength (λ/4) transmission line resonators and the additional shunt-series LC resonators, which produces the resonances at harmonic frequencies. In the realization process, the circuit is implemented using microstrip lines and applied as the output MN (OMN) of the proposed class-F⁻¹ MA. To validate the proposed design method, three class-F⁻¹ MAs with different OMNs are designed with f₀ of 6 GHz using CGHV1F006S GaN HEMT. With the same input power (P_in) level, the output power (P_out) and drain efficiency of the proposed class-F⁻¹ MA with BPF OMN are better than those of the conventional class-F⁻¹ MA (CMA) cascaded with conventional BPF (CBPF) about 0.42 dB and 5.1%, respectively. Moreover, the circuit size is reduced by about 35.68%.