Research Of Solid State Power Ampilifer As The Pre-stage Of Gyrotron

With the development of modern electronic technology, communications,electronic warfare and millimeter wave radar system, high power demand for miniaturization is more and more important. However, the millimeter wave solid-state power amplifier has become the most development potential and application prospect as a millimeter wave transmitter power source due to its advantages of low DC voltage consumption, small volume, light weight, convenient manufacture, stable performance and high synthesis efficiency. At the same time, the solid state power amplifier is used as the front stage stable power source of the gyro-devices, the advantages of solid state devices and gyro-devices can be integrated to meet the requirements of the volume,weight, reliability and other aspects of the military system.This paper introduces the classification, performance index, power synthesis technology and the main factors affecting the efficiency of millimeter wave solid-state power amplifier. We will study it from the power synthesis theory, the selection of the chip, the design of the waveguide microstrip transition structure, the design of the power distribution / combiner, the active power amplifier design, the debugging and testing of the power amplifier. Based on the combination of theory and practice, the design of Ka band high isolation compact broadband solid state power amplifier is presented, which can be used to design and develop the high power and high performance solid state power amplifier. In this paper, the main research contents are as follows:First of all, we design the waveguide to microstrip transition structure with wide bandwidth, low insertion loss and the power divider with wide bandwidth, high isolation and good amplitude and phase consistency. Then we design a compact eight /sixteen power combiner networks based on the E-plane magic-T power divider unit. It provides the design scheme for the subsequent passive 27?33.5GHz frequency range 7W power amplifier and 32?38GHz frequency range 20W power amplifier design.Then, based on the waveguide microstrip probe transition structure, the design of 27?33.5GHz frequency range driver amplifier is completed. At the same time, the design of 27?33.5GHz frequency range 7W solid state power amplifier based on waveguide microstrip double probe transition structure and E-plane magic-T power divider structure is also completed. After testing, the input reflection coefficient of the amplifier in the 27?38GHz frequency range is less than -10dB,and in the 32?36.5GHz frequency range is less than -20dB. The insertion loss of the whole passive structure is 1.2dB. In addition, in the 27?33.5GHz frequency range,the amplifier minimum saturation output power is 33dBm,the maximum is 39dBm. In the 27?30.5GHz and 31.5?32.5GHz frequency range,the output power is greater than 37dBm,so it achieves good results.Finally, the 32?38GHz frequency range 20W solid state power amplifier is designed based on the E-plane T power divider, the T type junction power divider, the H-plane waveguide bend and the waveguide microstrip H-plane probe transition structure. Compared with the traditional design that the power divider/combiner structure and power amplifier chip is in the same layer, all the power amplifier chips are arranged in the chamber body, and the power divider / combiner network structure is processed separately, which avoids the influence of the chip installation, and solves the problem that the chip bias circuit is difficult to be installed in the process of the compact multi-channel synthesis. After testing, the input reflection coefficient of the amplifier in the 30?40GHz frequency range is less than -10dB. In addition, the saturation output power in the frequency range of 31.3?40GHz was greater than 43dBm, in the 30?31.3GHz frequency range,the saturation output power is 41?43dBm,and the maximum saturation output power is 44.29dBm at 36.4GHz frequency point ,so it achieves good effect.