Multi-Band High Efficiency Power Amplifier

Achieving high efficiency power amplification over multi-octave RF bandwidths pose many design challenges. Conventional design techniques do not support high efficiency operation since use of distributed matching circuits and/or multiplexing several power amplifiers incur nonoptimal matching environments or high output losses. A new design approach is discussed whereby using the latest Gallium Nitride transistor technology and leveraging a Class E circuit environment, multiple electronically switched output networks are provided to the RF transistor providing high efficiency operation over multi-octave RF bandwidths. Two electronic switching elements are considered including PIN diodes and RF transistors. Using commercially available components, measurements are conducted on a physical prototype using PIN diode switch elements demonstrating typical efficiencies of 50% over two octaves bandwidth and at frequencies up to 2.4GHz.