Development Of L-band Solid State Pulse Power Amplifier

Pulse amplifier is widely used in radar and radio communications transmitter, is the core component of the transmitter, whose performance directly determines the performance of the entire communication system. Compared with the vacuum devices, solid-state device has the advantages of compact structure, good reliability, low working voltage advantages. The solid-state pulsed power amplifier has become a hot spot of research.The design of L band solid state pulse power amplifier will be shown in this paper. After analysis and comparison, the power amplifier and the pulse modulation circuit architecture were selected. The amplifier consists of pre driver, driver stage and power amplifier stage in three stages. This paper introduced the classification of power amplifier, according to the characteristics of different types of power amplifier, driver stage worked in class A and power amplifier worked in class AB. The use of ADS software, using the method of small signal S parameters and simulation the stability factor amplifier, design the input and output pre driver and driver stage matching circuit and a DC bias circuit, ensure the amplifier stable work. With the method of load pull simulation design of the input and output matching circuit of power amplifier, to ensure that the output power and gain amplifier to meet the design requirements. Based on the ADS software, the power amplifier layout was simulated by Momentum, the simulation results with the actual situation to. This paper describes the characteristics of switching modulation contrast, the gate modulation, drain modulation of different modulation methods, the final choice of the drain modulation. With the rapid rising and falling edge of the driving transistor power MOSFET drain pulse modulation. In this paper, for the power amplifier stage temperature compensation circuit is designed, the influence of temperature on power amplifier quiescent operation point down to the lowest. Finally, design the PCB layout of power and modulation circuit using Protel99 software. Use AutoCAD software to design the circuit layout and metal shield structure of RF amplifiers.After the completion of the design and Simulation of power amplifier and modulation circuit, the need for the actual circuit testing. This article describes the debugging process what issues need attention, and for different circuit module and pulse power amplifier machine design different test scenarios. The use of vector network analyzer, signal source, power meter, attenuator test instrument was used to test circuit. Finally, the measured gain of the 31 dB driver amplifier, power amplifier’s gain is 20 dB, the pulse output power reaches 250 W.In the working frequency band gain flatness is less than 1dB. The rising edge of the pulse of 35 ns, falling 40 ns, the stability and top landed of the pulse envelope are less than 0.81 dB, to the design specifications.Finally, a summary of the text, the conclusion, points out the shortcomings in this article, and put forward the improvement direction of the corresponding.