Research And Implementation Of Miniaturization Ka-band Linear Channel Amplifier

With rapid development of mobile communication system,the demand of high-throughput multi-channel satellite communication is increasing day by day,thus for the load equipment volume weight,performance indicators and other requirements are more stringent.Microwave power amplifier is the key single transmitter in satellite communication system and mobile communication system.Among them,the Traveling Wave Tube Amplifier(TWTA),with large output power and wide working frequency band is the most important single unit in satellite load.However,the multi-carrier mode greatly affects the system efficiency and spectrum utilization,duo to the amplitude and phase of the amplifier are nonlinear intermodulation products.On the other hand,for larger wider bandwidth and data processing capacity as well as narrower wave beam,the communication system is developing for higher frequency.However there is relatively heavy rain attenuation in Ka and above frequency band,which can be well solved by gain control in the space through channel amplifier.In this paper,linearized channel amplifiers with linearity correction,gain control,temperature compensation and other functions are taken as the research subject.The research emphasis is the linearizer base on analog pre-distortion technique.The main research contents are as follows:1.Analyze the requirement of satellite communication system linear power amplifier.Through literature search,this paper briefly summarizes the development origin of TWTA,EPC and linearization technology,introduces advanced technology foundation and scientific and technological achievements of various countries,and compares the development status of linearization technology at home and abroad.2.Analyze the nonlinear distortion characteristic of power amplifier and common mathematic models in principle.Detailed study of the current several kinds of commonly used microwave power amplifier linearization techniques,including: power back-off,feedback,feed-forward,pre-distortion and LINC.Analyze their theory and compare their applicable range,advantages and disadvantages.3.According to the application characteristics in space and the TWTA model,the design scheme in this paper is realized by using the simulated pre-distortion method.Detailed research and simulation verification of the simulated pre-distortion device are carried out.4.This paper presents the design of a linear channel amplifier(LCAMP)including drive amplifier,pre-distorter and final amplifier.The LCAMP adopts advanced DC control and RF miniaturization and integration of PCB technology,has realized the integration within the same structure design.The FPGA technology adopted has the functions of gain control,temperature compensation and nonlinear shape control,etc.In this paper,the design is verified by physical test and the results of verification compliance are given.