Drain 바이어스 제어를 이용한 Hybrid Doherty 증폭기의 성능개선

Performance Enhancement of Hybrid Doherty Amplifier using Drain bias control

  • 이석희 (단국대학교 전자컴퓨터공학과) ;
  • 이상호 (단국대학교 전자컴퓨터공학과) ;
  • 방성일 (단국대학교 전자컴퓨터공학과)
  • Lee Suk-Hui (Dept. of Electronic and Computer Engineering Dankook University) ;
  • Lee Sang-Ho (Dept. of Electronic and Computer Engineering Dankook University) ;
  • Bang Sung-Il (Dept. of Electronic and Computer Engineering Dankook University)
  • 발행 : 2006.05.01

초록

본 논문에서는 3GPP 중계기 및 기지국용 50W급 Doherty 전력증폭기를 설계 및 제작하였다. 이상적인 Doherty 전력증폭기는 효율개선과 고출력 특성이 뛰어나지만 이를 구현하기 위해서는 바이어스 조절이 어렵다. 이를 해결하고자 기존의 Gate 바이어스 조절회로를 가진 Doherty(GDCHD) 전력증폭기에 Drain 바이어스 조절회로를 첨가한 GDCHD(Gate and Drain Control Hybrid Doherty) 전력증폭기를 구현하였다. 실험결과 3GPP 동작주파수 대역인 $2.11{\sim}2.17\;GHz$에서 이득이 57.03 dB이고, PEP 출력이 50.30 dBm, W-CDMA 평균전력 47.01 dBm, 5MHz offset 주파수대역에서 -40.45 dBc의 ACLR 특성을 가졌으며, 각각의 파라미터는 설계하고자 하는 증폭기의 사양을 만족하였다. 특히 GDCHD 전력증폭기는 일반적인 Doherty 전력증폭기에 비해 ACLR에 따른 효율 개선성능이 우수하였다.

In this paper, design and implement 50W Doherty power amplifiers for 3GPP repeater and base station transceiver system. Efficiency improvement and high power property of ideal Doherty power amplifier is distinguishable; however bias control for implementation of Doherty(GDCHD) amplifier is difficult. To solve the problem, therefore, GDCHD(Gate and Drain Control Hybrid Doherty) power amplifier is embodied to drain bias adjustment circuit to Doherty power amplifier with gate bias adjustment circuit. Experiment result shows that $2.11{\sim}2.17\;GHz$, 3GPP operating frequency band, with 57.03 dB gain, PEP output is 50.30 dBm, W-CDMA average power is 47.01 dBm, and -40.45 dBc ACLR characteristic in 5MHz offset frequency band. Each of the parameter satisfied amplifier specification which we want to design. Especially, GDCHD power amplifier shows proper efficiency performance improvement in uniformity ACLR than Doherty power amplifier.

키워드

참고문헌

  1. R. J. Wilkinson, P. B Kenington, 'Specification of Error Amplifiers for Use in Feedforward Transmitter', lEE Proceeding-G, vol.139, no. 4, Aug, 1992
  2. W. H. Doherty, 'A New High Efficiency Power Amplifier for Modulated Waves', Proceedings of the IRE. Vol. 24, No.9, pp. 1163-1182, 1936 https://doi.org/10.1109/JRPROC.1936.228468
  3. Steve C. Cripps, 'RF Power Amplifiers for Wireless Communications', Artech House Inc, Norwood, MA, pp. 225-235, 2000
  4. Upton, David M., and Maloney, Peter R. et al, 'A Microwave Doherty Amplifier', IEEE MTT-S Symposium Digest, pp.1653-1656, 1994
  5. Youngoo Yang, Jeongheyeon Cha, Bumjae Shin, Bumman Kim, 'A Fully Matched N-Way Doherty Amplifeir With Optimized' Linearity', IEEE Transactions on Microwave theory and techniques, Vol. 51, No.3, pp. 986-993, 2003 https://doi.org/10.1109/TMTT.2003.808713
  6. 조경준, 'A Study on the Doherty Technique for Improving the Efficiency of a Feedforward Linear Power Amplifier', 광운대학교 박사학위논문, pp. 34-38, 2003
  7. F. H. Raab, 'Efficiency of Doherty RF Power Amplifier Systems', IEEE Transactions of Broadcasting, Vol. BC-33, No.3, pp. 77-83, 1987 https://doi.org/10.1109/TBC.1987.266625