The Research Of Microwave Solid-state High Power Amplifier

With the continuous development of the microwave solid-state high power amplifiers, high power devices are not only widely used in radar technology and wireless communication technologies, but also enable us to improve the output power and the power additional efficiency of the microwave solid-state high power amplifier. Therefore, the power synthesis technology becomes one of the most simple and effective means to improve radar and wireless communication system output power. It not only has high research value, but also plays an important role in practical applications. Throughout the course of the microwave solid-state high power amplifiers in recent decades, microwave power synthesis technology is the direction of high frequency, multi-channel and broadband.The project is mainly researching on X-band(8.5-9.5GHz) internal matching in synthesis technologies of microwave solid-state high power amplifiers, such as the transistor matching technology, power divider/combiner technology and the DC bias technology. According to the input and output impedance of HEMT die and the characteristics of the output power, we design a high power amplifier based on the two-way matching synthesis technology using theoretical analysis and practical method of combining the microwave circuit simulation. Then the schematic simulation, layout-schematic co-simulation, processing packaging and commissioning are also proceeded.Based on the high output power, the high power efficiency and the high gain of microwave solid-state high power amplifier, we firstly introduce the basic theory of the circuit structure of high power and high efficiency power amplifier design. Then we do some research and analysis on the basis of the theory, finding out the relationship between the topology of the circuit and the efficiency and stability, making a scheme of index distribution solution, choosing and purchasing transistors, and designing the scheme of circuit principle diagram. Secondly, according to the assigned targets, we design a circuit topology with the output power of 40 W, then with the help of modeling and layout-schematic co-simulation of ADS software, we make some research and analysis on the bias circuit and structural stability of the amplifier, using the load-pull method, we measured the maximum output power and maximum power point efficiency of input and output impedance of the transistor die at 9GHz center frequency, and designed the matching network structure, power divider/combiner network structure and the bias circuit structure with the Smith chart matching method. Finally, we make optimization and simulation for the whole circuit structure, design a testing cavity structure, draw a PCB layout according to the simulation results and make implementation of the amplifier circuit layout and the testing cavity, then test the whole amplifier circuit.The two-way synthesis microwave solid-state high power amplifier circuit consists of the bias structure, the "T"-type power divider/combiner network structure, the structure of the input and output matching, LCL filter network structure and the matching circuit structure of HEMT die. Finally, we use microwave signal sources, DC power supplies, attenuators, power meters and the spectrum analyzers to test the high power amplifier, with the bias condition of Vds=30V and Vgs=-3.6V, in the 8.5GHz-9.5GHz range, the test results are as follows: power gain(G)>11dB, the input VSWR<1.8 and the output VSWR<2.2, the output power(Pout)> 36.65 dBm and power added efficiency(ηPAE)> 30%.