Design Of High Power Broadband Good Gain Flatness RF Power Amplifier

RF power amplifiers are the key components in wireless communication systems andradar systems, the performance of the RF power amplifier is very important for the wholesystem performance. Broadband RF power amplifier is becoming a popular researchinterest these years because the application in Electronic warfare systems, Securitycommunication systems, radar systems, High-speed optical fiber communication systems,wideband test measurement and so on. It’s very difficult to gain good flatness and outputhigh-power in the broadband work frequency because the gain of the device falls off atapproximately6dB/octave.In the research, we need design a RF power amplifier which can work from30MHzto400MHz. The P1dBoutput power of the PA is more than49dBm, and the flatness is lessthan±0.5dB in the work frequency, the power added efficiency of the PA is more than30%. Among these targets, achieving the fine flatness is the greatest difficulty.In this paper, we briefly introduce the research status and the research value of theBroadband RF power amplifier, the application of the broadband RF PA in militarysecurity communication, the classification of the RF PA, the foundation of the designtheory, and focus on the nonlinearity characteristics of the power amplifier such asAM-AM, AM-PM. After comparing a variety of design scheme, we decide toselect the push-pull amplifier structure as the structure of the whole amplifier. Startingfrom the chosen of the device, we introduce the simulation of the project and thedebugging of the PA, and then we show the practical measure result of the amplifier. Andthen we use Simplified Real Frequency Technique to improve the flatness of the PA tosatisfy the target of the project, and show the practical test result.The practical test result show that, in the whole required work frequency, the P1dBoutput power of the RF power amplifier is more than49dBm, the power added efficiencyis more than32%, and the flatness of the PA is less than±0.5dB. All of the practical testresults meet the initial design requirement.