Research Of Solid State Power Ampiliferas The Pre-stage Of Gyrotron

Gyrotron traveling wave tube(also known as gyro-TWT) is a new type of millimeter wave and sub millimeter wave band high power gyrotron devices. It has characteristics of high gain and high efficiency, and also has wide bandwidth. But for achieving higher output power, an input single with enough power should be got to drive the gyro-TWT. The solid state power amplifier with the advantages of small size, low voltage, good consistency, well stability as the front stage amplifier circuit driving gyro-TWT is put forward. It has been widely used in practice, and greatly promotes the development of the millimeter wave power source system with gyro-TWT.This article starting with the basic theories of solid state power amplifier and power combining, designs an 8mm band solid-state 20 W pulse power amplifier. It has the advantages of small size, low noise, and goodstability characteristics. At the same time, in order to cooperate with the gyro-TWT, this paper also designs a ferrite isolator and a gain equalizer. In view of the various functional components of solid state power amplifier, this paper mainly includes the followings:1. The classification and characteristics of millimeter wave solid-state power amplifier, and the related theories on power combining network are arranged, providing theoretical support for the following designs.2. For lower noise and smaller size, the selection of chips and circuits is completed. The continuous wave output power of the one-way amplifier module achieves to 2W. And it designs a rectangular waveguide to microstrip transition, for assembling between modulesconveniently.3. In order to make the power amplifier output power reaching the final goal, it has to use power combining structure. After the comparison between different structures, it finally chooses the radial waveguide structure as the power combining network prototype. Using the transform structure of coaxial to rectangular waveguide, a 8-way power combining network with taper transition structure and a 12-way power combining network with radial waveguide cavity structure have been designed and they all have good performances. Manufacturing and testing have been taken for the 8-way structures.4. A pulse modulation circuit is joined in the power amplifier module to make the amplifier in pulse working status. And the further simulation is taken in Pspice. After that, two power supply circuits are designed for power amplifiers.5.Theworking principle of ferrite isolators is analyzed. Using the Faraday Gyromagnetic Effect, an 8mm band ferrite circulator and a isolator based on this circulator are designed, in order to increase the isolation between each amplification link,or between the solid state power amplifier output port and the gyro-TWT input port.6.The working principle ofcommonly used gain equalizersis analyzed. According to the gain characteristics of gyro-TWT, using the rectangular cavity wave-notching units loaded with Chebyshev absorbing material, the design of an 8mm band cavity gain equalizer, ensures the high gain stability of the gyro-TWT.