A Study on Efficiency Extension of a High Power Doherty Amplifier Using Unequal LDMOS FET's

불 균등한 LDMOS FET를 이용한 고 출력 도허티 증폭기의 효율 확장에 관한 연구

  • Hwang, In-Hong (Dept. of Radio Science and Engineering, Kwangwoon University) ;
  • Kim, Jong-Heon (Dept. of Radio Science and Engineering, Kwangwoon University)
  • 황인홍 (광운대학교 전파공학과) ;
  • 김종헌 (광운대학교 전파공학과)
  • Published : 2005.11.05


In this paper, we present an efficiency extension of Doherty power amplifier using LDMOS FET devices with different peak output powers and an unequal power divider. The amplifier is designed by using a MRF21045 with P1 dB of 45 W as the main amplifier biased for Class-AB operation and a MRF21090 with P1 dB of 90 W as the peaking amplifier biased for Class-C operation. The input power is divided into a 1:1.5 power ratio between the main and peaking amplifier. The simulated results of the proposed Doherty amplifier shows an efficiency improvement of approximately 19 % in comparison to the class-AB amplifier at an output power of 42.5 dBm. The fabricated Doherty amplifier obtained a PAE of 33.68 % at 9 dB backed off from P1 dB of 51.5 dBm.


Doherty amplifier;LDMOS FET;P1 dB;PAE (Power-added efficiency);PAR