Broadband Continuous Class- ${\rm F} ^{-1}$ Amplifier With Modified Harmonic-Controlled Network for Advanced Long Term Evolution Application

This letter presents a highly efficient broadband continuous Class- F ^-1 power amplifier (PA), which employs the modified simplified real frequency technique (SRFT). In highly efficient PA design, a low-pass matching method is preferred for its harmonic impedance controlling. However, the qualification ( ) in transforming lumped components of filter prototype to transmission lines (TLs) imposes a restriction on its application. To overcome this limitation, a modified SRFT procedure is employed to optimize fundamental impedance and control the harmonic impedance directly with TLs. The proposed design strategy is experimentally verified by a 1.7~2.8 GHz PA design with 80.4% maximum efficiency and 10-W output power. The 100 MHz long term evolution advanced (LTE-A) signal is applied to this PA and the linearization result shows a well -46.4 dBc performance by digital pre-distortion (DPD) at 2.55 GHz.