The Study Of S-band GaN HEMT Internal Matching Power Amplifier

As the third generation of semiconductor,Gallium Nitride (GaN) is becoming the first choice of microwave power device material,because of its excellent electrical and chemical characteristics,like wider band-gap, high saturated electron speed and higher break-down voltage, and thermal conductivity. Internal matching device and circuit based on the Gallium Nitride HEMT with advantages of high operating voltage, high output power, large frequency bandwidth, small size and loss of small, have a broad application prospects in phased array radar system and other military or commercial fields.So in the context, the GaN HEMT Internal matching circuit is being studied in the world.In this dissertation the study is to develop high-performance S-band HMIC power amplifier based on GaN High Electron Mobility Transistor.The key design technologies were worked about the power amplifier,such as circuit topology,large signal optimization design,and circuit stability. And the impedance matching was made a detailed theoretical analysis.At the same time, a circuit design flow was set up. By the method of load-pull,the best power parameters of input and output impedances at the frequency of 2.8GHz were got.Finally,we design the matching network and bias circuit by using the Smith Chart of ADS.Coupled with Wilkinson coupler, a S-Band Internal Matching Power Combining Amplifier was developed successfully. With the gate bias of -2.9V and the drain bias of 32V, the small-signal S parameter test was shown that from 2.7～2.9GHz, the linear gain is from 8.2 to 9.3 dB, VSWR<2. At middle frequency 2.8GHz,the maximum pulsed-output power is 60W, the maximum PAE is 37.5%.