Dual‐Band Input–Output Waveform Engineered High‐Efficiency Power Amplifier With Large Frequency Ratio and Adjustable Transmission Zeros

ABSTRACT This paper proposes two novel modes based on input–output waveform engineering and a compact dual‐band output matching network (DB OMN) with two adjustable transmission zeros (TZs), for the design of dual‐band power amplifiers (DBPAs) with large frequency ratio. For the first time, the two modes considering input nonlinearity of the transistor are leveraged to construct two new expanded optimum drain load impedance spaces (DLISs), thereby reducing the complexity of designing DB OMNs. Based on this, the maximum frequency ratio of the proposed DB OMN can theoretically reach 7.6. Additionally, two adjustable TZs can be produced, and its frequency ratio is confirmed in the range from 1.6 to 7.6. For demonstration, a prototype operating at 0.7 and 2.64 GHz is implemented with frequency ratio of 3.8, and two TZs at 0.9 and 2.08 GHz are purposefully introduced. Measured results show that the DBPA exhibits the power added efficiencies (PAEs) of 83.2% and 70.9% with output powers of 41.9 and 40.9 dBm at 0.7 and 2.64 GHz, respectively. Meanwhile, the output powers of only 1.9 and −8.1 dBm are obtained at 0.9 and 2.08 GHz, respectively.