| In the Radio communication Systems, the power amplifier is the key components. The performance of power amplifier restricts the technical level of the whole system. With the development of the communication system, the performance, such as efficiency and output power, become more and more high. But the capability of the traditional semiconductor is deficiency, the third-generation semiconductor become important.GaN HEMT device is a typical member of the third generation semiconductor materials. GaN HEMT devices provide an extremely high breakdown voltage and power density capability, as soon as high electron mobility. The design of GaN HEMT Power Amplifier is very popular. We study the characteristic and big signal module of the GaN HEMT transistor.The power amplifier can be divided into tow classes, the traditional linearity amplifier and switch module amplifier. The traditional linearity amplifier also can be divided class A, class B, class AB and class C. The switch module amplifier also can be divided class D , class E, class F. Through the research of Power Amplifier, the ideal efficiency of class F power amplifier is 100%, and its output-matching network can suppress the harmonic output-power. We use maximally Flat Waveforms technology and harmonic-control theory to design class F power amplifier. Because the maximal voltage of the drain is very high, and the breakdown voltage of GaN HEMT transistor is high, so we usually use GaN HEMT transistor to design class F power amplifier.According to the aim of the project, we choose the feat transistor. Based on the big signal modal, load pull technology and harmonic balance technology, we will design a class F power amplifier at L band frequency. Finally, the designed amplifier is simulated by using the EDA tool ADS2005. According to the simulated results, the add efficiency of power exceed 75%, and the output-power is 42dBm. The performance of class F power amplifier is good, meat the request of high efficiency and high output-power. |
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