Efficient High Frequency Electromagnetic Source for Communication Devices

The objective of this proposal is to demonstrate a solid-state broadband high power high efficiency class B push-pull amplifier design using spatial power combining technique for GaN power amplifiers. The solid-state amplifier is designed to replace the tube amplifiers and provide efficient and linear power for communication system. Although the GaN amplifier can output power in tens of watt, it is still inferior to vacuum tubes that can generate hundreds of watt output power. To further increase the output power from semiconductor devices, the corporate combiner is one of the classic and most popular structures. But the physical layout of the corporate combiners with many elements causes the transmission lines in the last stages of combining to become very long. As the number of devices increases, the losses in these lines become insurmountable and lead to low efficiency. High losses associated with circuit combining schemes can be avoided with coaxial waveguide spatial power combining technique since the energy is combined in the lossless waveguide space or low loss electric medium. The intrinsic 180 degree broadband balun incorporated inside of the combiner is ideal for Class B Push Pull amplifier design. The overall efficiency of the high power amplifier will be much improved by integrating the Class B Push Pull GaN amplifier cell and coaxial waveguide spatial combiner together.