Research And Design Of A Balanced Ultra-wideband Power Amplifier

With the rapid development of wireless communication,different requirements of communication system arise at the historic moment.Different communication standards and different working modes of various systems can coexist,such as GSM,5G and WLAN,etc.These communication systems have brought great convenience to our life.At the same time,we also have higher and higher requirements for communication,which promotes the frequent development of modern mobile communication technology,increases the communication frequency,widens the communication bandwidth,and rapidly updates the communication equipment.This makes people have higher and higher requirements for the performance of RF power amplifier.Therefore,this paper finally chooses the high-power wideband amplifier covering the whole S band as the research target.In this paper,a 2-5GHz wideband power amplifier is designed,which takes GaN HEMT as the core device and microstrip line as the main circuit realization means,with the design of super-large bandwidth as the main goal and the full use of wideband matching theory.By comparing and analyzing the performance of various kinds of wideband amplifiers,a balanced structure is selected to compensate the poor input and output standing waves of the wideband amplifiers,so as to improve the stability of the amplifier in the case of mismatching and impedance matching point deviation in practical application.The small-signal parameters of the pipe core are collected by the load-pull and manual probe system,and impedance matching is realized by the combination of multi-stage low-pass LC network and 1/4 wavelength line,and the input and output matching network is designed.The circuit simulation function of ADS software was used to draw the microstrip layout,and the S-parameter simulation of the whole amplifier circuit was carried out.Finally,the assembly,debugging and testing of the real object were completed.The test results show that when the drain voltage is 48V,the input period is 1ms,and the duty cycle is 10%pulse signal,the amplifier can obtain the output power of 49.6dBmand the maximum output power can reach 51.2dBm in the 2-5GHz frequency band when the transistor is operating in AB class.The saturation gain is greater than 7.7dB,and the maximum saturation gain can reach 9,3dB.The additional drain efficiency is not less than 34,1%,and the maximum additional efficiency can reach 43,1%.At present,there are few papers about the inner-matched balanced wand-band amplifier at home and abroad.The power amplifier has smaller size,larger output power and drain efficiency than the outside-matched amplifier,and it has certain reference value for the study of the same type of amplifier.