The Research Of Spaceborne GaN Microwave Solid-state Power Amplifier

The power amplifiers for space are key components of the satellite communication systems. Power consumption, linearity, volume, weight and anti-radiation of power amplifiers are limited in Aerospace applications. Compared to the classic electric vacuum Traveling Wave Tub,solid state power amplifier has the advantages of little volume, large dynamic range,low power dissipation,long natural life and so on. The third-generation semiconductor material, such as wide band gap Ga N, has some advantages of big power density; high breakdown voltage and high electron saturation drift velocity compared to Gallium Arsenide semiconductor material. At present, Gallium Arsenide material is the most widely used material in the design of solid state power amplifier. Now, microwave devices based on Ga N have been used in high-efficiency electronic systems. The results from some applications showed that the efficiency of an X-band Ga N power amplifier was to 45 %, in which was close to the efficiency of traveling wave tube amplifier. In recent years, Ga N power amplifiers in several bands have already possible of replacing traveling wave tube amplifiers for the spacecrafts.The study of an S-band Ga N solid state power amplifier(SSPA)for satellite data transmission systems is carried out in this paper. The design scheme of an S-band solid state power amplifier with 20 MHz bandwidth, 10 W output power and efficiency of 48% was presented.The paper consists of five chapters as followed.In the first chapter, the characteristics of Ga N HEMT power amplifiers and characteristics of the semiconductor material amplifier are introduced, and the development of Ga N microwave solid state power amplifier is described.In the second chapter, some basic knowledge of microwave solid state power amplifier was explained, including main characteristics, classification and common design methods of microwave solid state power amplifier.In the third chapter, the design process of an S-band Ga N SSPA is described. The SSPA consists of two stages. The design of the impedance matching circuit, bias circuit and timing control circuit with temperature compensation of single stage power amplifier is finished,and a prototype amplifier is implemented. The simulate and design of a compact wide band microstrip filter is also finished and the testing results of the filter are analyzed in detail.In the fourth chapter, the tests of the characteristics of S-band 10 W power amplifier for space are finished. The results of this S-band SSPA are analyzed.In the fifth chapter, the main contents of the paper are summarized and the next works are described.