Research And Design On Broadband GaN Power Amplifier MMIC

With the rapid development of modern electronic communication technology,monolithic microwave integrated circuit have wide applications in electronic communication systems due to their small size,light weight,good reliability,strong anti-interference ability and good consistency.As an important part of monolithic microwave integrated circuit,broadband power amplifier chips are the core of phased array radar and military electronic warfare systems,and have been one of the research hotspots in recent years.Based on the requirements of a project,this paper presents an X~Ku band broadband power amplifier based on 0.25 ?m GaN HEMT process.The accuracy of the GaN HEMT model is especially important for broadband power amplifier designs.Within the model,the output impedance of the GaN HEMT is one of the key parameters that decide the quality of the broadband matching and bandwidth enhancement.However,to obtain accurate large signal models for GaN HEMTs are always big problems.In order to improve the accuracy of the design,an equivalent RC model of active devices' large signal output impedance is proposed,and the accurate output impedance of the GaN HEMT with arbitrary dimensions can be obtained.The RC model has a physical meaning for characterizing active devices that have current and voltage swing limitations.The RC model is directly used to replace the PDK model of the large signal output impedance of the GaN HEMT in the impedance matching network design of the broadband power amplifier.The circuit design of the broadband power amplifier consists of two stage.The first stage adopts a negative feedback structure to reduce the Q value of the impedance matching network.The band-pass matching network topology is used to realize the broadband impedance matching network,and the broadband power amplifier chip is successfully achieved.The on-chip test system and the fixture test system were built,and the performance indicators of the chip were tested in all aspects through the micro-assembly of the broadband power amplifier chip.The test results show that at 28 V operating voltage,the broadband power amplifier achieves saturated output power over 30 dBm,power added efficiency over 21%,and power gain over 15 dB in the 8 to 18 GHz operating band.The chip size is 2.20 mm×1.45 mm.The MMIC chip has the characteristics of wide bandwidth,high efficiency and small size.It can be mainly used in fields such as millimeter-wave transceiver components and wireless communication,and has broad application prospect.