| Power amplifier of high output power, high power gain, good linearity andefficiency is widely used in mobile communication system, digital transmitter andmilitaryaffairstechnologyfield.In order to design high output power, high power gain and good efficiencymicrowave PA(Power Amplifier) with the frequency1600 MHz~1630 MHz, the inputand output impedance of used microwave power transistors are gained by 2-toneload-pull method basing on the analysis of unconditional stability. Matching networksare designed by the conjugate match method. More accurate matching networksMOMENTUM components are designed by MOMENTUM method introducingfull-wave arithmetic, by which accurate EM model produced and the coupling andparasitics considered. With the MOMENTUM components the design veracity isimproved. Comparing the large signal results of ideal schematic and applyingMOMENTUM components in ADS simulation, which shows the 3-stage LDMOSmicrowave PAdesign is exact. Finally a 3-stage LDMOS microwave power amplifierof P1dB larger than 30W and over 50 dB power gain with the frequency 1580MHz~1650 MHz and over 30% PAE, is successfully designed. The 3-stage layout ofpoweramplifierisgainedandthepoweramplifierismadeaccordingtodesign.A new method of carrier complex power series (CCPS) is carried out to analyzethe two nonlinear phenomena AM-AM and AM-PM of microwave PA. The CCPSmethod, which accurately calculate the nonlinearity AM-AM and AM-PMsynchronously, has advantage over classical Taylor series in which only the AM-AMcan be analyzed. In order to eliminate the nonlinearity of PA, according to theexpression of ICCPS, a linearizer predistorter, simple in configuration and easy toimplement, is designed and simulated by using the nonlinearityof diode. The accurateexpression of circuit model is deduced and precise value of amplitude and angle areobtained. In ADS simulation, the predistorter greatly improves the nonlinearity ofLDMOS microwave PA by 26dB on IMD3, which validates the veracity of analysisanddesign. |
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