도허티 이론을 이용한 전력증폭기의 효율 향상에 관한 연구

A Study on Improving Efficiency of Power Amplifier using Doherty Theory

In this paper, Doherty amplifier is designed by the need of improving the linearity and efficiency of wireless network and repeater for WCDMA. It is designed to maintain the high linearity and efficiency at the low efficiency period of the power amplifier after analyzing Doherty technique using the active load-pull in condition of the high efficiency power amplifier implementation according to the variation of input power. CW 1-tone experimental results at the WCDMA frequency 2.11~2.17 ㎓ shows that Doherty amplifier, which achieves power add efficiency(PAE) 50 % at 6 ㏈ back off the point from maximum output power 52.3 ㏈m, obtains higher efficiency of 13.3 % than class AB. Finding optimum bias point after adjusted gate voltage, Doherty amplifier shows that IMD₃ improves 4 ㏈.