Microwave Power Combining Technique

In recent years,in the research process of microwave and millimeter wave satellite communication systems,people have increasingly recognized that high power amplifiers are the key components of the end of the transmission link.The output power directly determines the communication distance and communication of the whole system.Due to the limitations of impedance matching,process and heat dissipation,solid-state power amplifiers capable of outputting higher power are not easy to implement.Only microwave power synthesis technology can be used to combine multiple monolithic power amplifier chips to achieve a higher power solid state Amplifier.In this paper,aiming at the current state of Ku-band solid-state power amplification technology,and taking into account the shortcomings of waveguide and space power synthesis,a power synthesis technique based on stripline structure is selected to develop a commercial Ku-band continuous wave output power of 20 W.The solid-state power synthesis amplifier has been tested and analyzed with relevant indicators.Based on the basic design theory of power amplifier,the paper introduces the general design method of Ku-band microwave power amplifier in detail.In the technical scheme formulation and power distribution/synthesis network design process,the following work is completed: the basic design theory of power amplifier is deeply discussed.Especially in the aspects of stability discrimination,circuit matching,and amplifier operation mode,the technical indicators such as power gain,gain flatness,third-order intermodulation,power added efficiency and power synthesis efficiency of power amplifier are introduced.The power amplifier system is divided into three modules: active circuit,passive network and power control.The modular design concept is used to refine the technical difficulties and solve them one by one.The Ga N power amplifier tube is used as the final power synthesis chip to meet the output power and Linearization technical indicators,and the selection of Ga N power devices and microstrip circuit dielectric substrates are discussed in detail;the power synthesis technology based on stripline is used to achieve specific power output;for driver stage amplifiers and final stage power amplifier tubes The bias circuit,power supply voltage control circuit,and power amplifier box structure are described in detail.Finally,the assembled power amplifier products are tested.The test results show that the power amplifier's various indicators meet the design requirements,in terms of product design.Has a high application value.In this paper,a solid-state power synthesis amplifier with a continuous wave output power greater than 20 W in the range of 14.5GHz to 15.35 GHz has been developed.Its overall external dimensions are 250mm×220mm×70mm,which meets the design requirements for miniaturization of equipment.The test results show that in the range of 14.5GHz to 15.35 GHz,the continuous wave output power is 20 W,the large signal power gain is greater than 43 d B,the output power flatness is 0.88 d B,and the output third-order intermodulation is-25.2d B.Reach and exceed design specifications.