The X-band Gan Power Amplifier Design

GaN-based microwave power amplifiers have high voltage, high output power, frequency bandwidth, low loss. So they have wide range of applications. In a large number of in-depth research on the basis of, this article summarizes the development status and developments of GaN-based power amplifier, and proceed from the traditional power amplifier, based on our laboratory-made GaN HEMTs, the establishment of the equivalent circuit model of the device, X-band GaN-based power amplifier design and analysis, to solve the high-power gate width device power combiner and odd mode oscillation. Main work and the results are as follows:Analysis of the basic theory of power amplifiers and GaN HEMTs, developed and tested the AlGaN/GaN HEMT devices, analysis of the cut-off frequency fT of26GHz, the maximum oscillation frequency fmax of35GHz, the establishment of the device small-signal equivalent circuit model and signal equivalent circuit model, the simulation results agree well with the test results.MMIC in the capacitance, resistance and inductance of the basic theory, the parameters of the planar spiral inductor simulation optimization results show that the number of turns N, the increase in line width W and line spacing S can improve the value of the inductor L.In the basis of the above study, summed up the design process and the topology of the GaN-based power amplifier, select the best impedance, RC stability of the network and the isolation resistor, the device is absolutely stable state. Choose a hybrid matching networks conjugate matching, output matching network is designed to achieve the purpose of power transmission and power combiner; design the input matching network to achieve the purpose of power gain and power distribution; the design of the interstage matching network to achieve the purpose of power transmission. The rational distribution of the microstrip lines combined with the electromagnetic field simulation to optimize the schematic circuit to get better results, in which the input VSWR VSWRin less than1.5, output VSWR VSWRout less than the2.0, the power gain Gp is greater than20dB, the stability factor μ greater than1, the maximum output power Psat to reach35.268dBm, have achieved the desired design goals, and finally through the L-EDIT software design of the amplifier territory.