MMIC Of Ku-band Power Amplifier Based On GaN HEMT

In recent years,with the increasing demand for wireless communication systems,spectrum resources have become increasingly congested.The operating frequency of communication systems is gradually shifting to higher frequency bands.As a key component in wireless communication system,power amplifier are required to achieve higher working frequencies,higher output power and smaller size to meet the practical requirements.To this end,researchers are constantly expolring new materials and structures to improve the performance of devices.As the third-generation semiconductor material,Ga N has attracted domestic and foreign scholars.because of its high breakdown field strength and high power density,which can achieve higher gain at higher frequencies.Microwave Monolithic Integrated Circuit(MMIC)has more compact size and higher consistency and reliability than hybrid integrated circuit,so it is widely used in high power amplifier.The thesis first introduces the development of power amplifier with the evolution of semiconductor materials and summarizes the relevant research works.Then,the basic theory and design idea of power amplifier are described briefly.On the basis of given index,Ga N HEMT process is selected for design.The power amplifier designed in this thesis adopts a three-stage cascade architecture,and all amplifiers work in Class AB to obtain better power efficiency.The last stage uses 16 cell output,and the output circuit uses the direct parallel matching structure with design flexibility and compactness for the power synthesis and impedance matching.The first two stages use the lossy matching structure to introduce the RC parallel circuit to eliminate the negative resistance effect of the transistor and improve the stability.Also,isolation resistors are added between the cores of each stage to eliminate odd-mode oscillations.The electromagnetic simulation results of the layout show that the output power is44 d Bm,the power addition efficiency is 37%-42%,the power gain is 25 d B,the input voltage standing wave ratio is less than 1.5,the output voltage standing wave ratio is less than 2.5 across 12-18 GHz,and the chip size is 3.5 mm×2.6 mm.Finally,the power amplifier module is designed.The measured results show that the saturation output power of the module is greater than 43 d Bm,the input voltage standing wave ratio is less than1.8,and tvoltage standing wave ratio is less than 2.7 throughout working frequency band.