| PA (Power amplifier) is widely used in radar, wireless communications, navigation, satellite communications, electronic counterwork and so on. PA of high output power, high power gain, good linearity and efficiency is widely used in mobile communication system, digital transmitter and military affairs technology field. 3G technology is the most interesting technology in the world now. PA which amplifies 3G RF signals should have good linearity, high efficiency, high output power and so on.Some base theories of PA were discussed in this paper. And some key issues such as wideband matching network were studied. Through theoretical analysis and simulation, a wideband LDMOS PA was designed, whose bandwidth is 1GHz, outputpower is 39dBm and gain is 40dB.In order to design high output power, high power gain and good efficiency microwave Power Amplifier with the frequency 1200MHz~2200MHz, the input and output impedance of used microwave power transistors are gained by 2-tone load-pull method. Matching networks are designed by the conjugate match method based on the analysis of conditional stability. More accurate matching networks MOMENTUM components are designed by MOMENTUM method introducing full-wave arithmetic, by which accurate EM model was produced and the coupling and parasitics was considered. With the MOMENTUM components the design veracity is improved. Comparing the large signal results of ideal schematic and applying MOMENTUM components in ADS simulation, which shows the 3-stage LDMOS microwave PA design is exact. Finally a 3-stage LDMOS microwave power amplifier of P1dB larger than 10W and over 40dB power gain with the frequency 1200MHz~2200MHz and over 25% PAE, is successfully designed. The 3-stage layout of power amplifier is gained and the power amplifier is made and debugged according to design. |
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