The Design Of LDMOS Microwave Wideband Power Amplifier

Microwave power amplifier is widely used in wireless communication, radar system, electronic-countermeasure equipment, navigation system and all kinds of industrial equipment. It is the core of radar power transmitter module and modern wireless communication. In wireless communication, military and other fields, with the development of new technology and standard, microwave PA is growing to the direction of high-performance and low-cost. Owing to its excellent properties and lower cost, the PA based on LDMOS transistor had been widely used in civilian and military fields. So, the research for the LDMOS PA has very important significance.Firstly, in this paper, the basic theory and primary indicators of the microwave PA are introduced, the depth understanding to these basic knowledge will contribute us to the design PA. In this paper, further theoretical analysis been given in the stability of microwave PA, some practical solution are proposed to solve the stability of circuit and some examples are given to explain it. In the design of power amplifier's impedance matching, this paper propose some principles and methods of impedance matching and give some specific forms of implementation. In the design of broadband PA, this paper present some methods can broaden frequency band and make corresponding summary. Especially, in terms of designing broadband matching network of PA by using multi-section microstrip impedance transformer combined with ADS, in this paper, the method is proposed which has great practical value and give theoretical analysis and examples in-depth. In the linearization techniques of PA, several measures can improve linearity been presented. In order to improve it's linearity, we make power back method used in the design of this subject's driver stage PA. Based on the above theory and method, a 3-stage LDMOS microwave PA of greater than 40W output power and over 35 dB power gain with the frequency 2400MHz-3000MHz and over 20% PAE is designed well in this subject. Finally, according to the optimized result, we draw the layout can been used for production processes, assembly drawing and the cavity of PA. The actual product had been made and the debugging and testing had been finished.The research and design of this project is a good persuasion and verification for the promotion of application range of the LDMOS power components. It can serve as a model and have some guiding significance to design higher gain, higher power, broadband or ultra-wideband PA fast and accurately.