Research On C Band High Efficiency GaN MMIC Power Amplifier

In the radar system,the power amplifier(PA)is an indispensable part of the end of transmitter front,and its power consumption has a direct impact on the complexity of the power supply and the reliability of the whole system.Therefore,the research of high efficiency power amplifier is a hot topic in the field of microwave solid state circuit.It is more mature to realize high efficiency with class E power amplifier and class F power amplifier.But it is so difficult for high power microwave monolithic integrated circuit(MMIC)to achieve higher harmonic control,that this paper focuses on the method of high efficiency power amplifier based on harmonic control technology.In recent years,gallium nitride(GaN)as the representative of the third generation semiconductor materials with its wide band gap,high breakdown electric field and other characteristics stands out in microwave solid-state power devices.The high breakdown voltage characteristics of GaN high electron mobility transistor(HEMT)can withstand higher harmonic voltage fluctuation in the harmonic control circuit,so the research on harmonic control of GaN HEMT high efficiency power amplifier design method has high theoretical significance and high value in engineering application.This paper,based on the domestic GaN HEMT technology around the harmonic control theory carried out the following two aspects of work:1)Research on high power amplifier with two harmonic control.For the high power MMIC amplifier circuit is complex,small size,it is difficult to achieve harmonic control circuit design.Because it is difficult for the high power MMIC amplifier with the characteristics of circuit complex and small size to realize harmonic control.Based on the design of the fundamental wave matching power amplifier,this paper researches the method of increasing a second harmonic controlling construction in the output end and achieved that the power added efficiency of 60 W GaN MMIC is greater than 42.5% in C band.The measured results agree well with the simulation results.Compared with the results of PA without harmonic control,the DC power consumption in the band is reduced by more than 8W,which effectively improves the efficiency of the power amplifier under the condition that the output power and gain are not lower than that of the fundamental wave matched power amplifier.2)Research on harmonic control based on Balun.The purpose of the design is to further enhance the efficiency of the power amplifier.The thesis explored the use of planar coupled balun structure to control the third harmonic and even harmonic suppression method.The purpose of reducing the even harmonic term in the output signal is obtained.The simulation results show that the even harmonic suppression at the center frequency of 5.5GHz reaches more than 42 dBc,which solves the problem of higher harmonic component control in high power MMIC.