A High-Efficiency Power Amplifier from 0.25 to 1.25 GHz Based on Qualified Impedance Solution Space

A design approach based on qualified impedance solution space for a broadband high-efficiency power amplifier (PA) is proposed. It helps to automatically circle out qualified optimized load impedance under specific design constraints, and it can ease the design of broadband PAs due to expanded target space compared to manual settings. All the data containing initial power and power-added efficiency (PAE) contours are exported from load-pull test bench and transformed to a qualified fitted space utilizing computer-aided design (CAD) software. This fully explored space containing the fundamental and the second harmonic frequency is adopted as the impedance solution space in the design of matching network (MN). An example PA operating from 0.25 to 1.25 GHz is designed. The measured results show that 11.2-14.4 dB of gain, 40.1-43.4 dBm of output power and 60.5%-75.4% of drain efficiency is delivered.