MEMS TUNING ELEMENTS FOR MICRO/MILLIMETER-WAVE POWER AMPLIFIERS

마이크로/밀리미터파 대역에서 전력증폭기의 효율향상을 위한 MEMS 튜닝회로

  • Kim, Jae-Heung (Electrical, Electronic, & Information Engineering, Kangwon National University)
  • 김재흥 (강원대학교 전기전자정보통신공학부)
  • Published : 2003.11.15

Abstract

A new approach, using MEMS, for improving the performance of high efficiency amplifiers is proposed in this paper. The MEMS tuning element is described as a variable-length shorted CPW stub. Class-E amplifiers can be optimally tuned by these MEMS tuning elements because their operation varies with the impedance of the output tuning circuit. A MEMS tuning element was simulated using full-wave EM simulators to obtain its S-parameters. A Class-E amplifier with the MEMS was designed at 8GHz. The non-linear operation of this amplifier was simulated to explore the effect of the MEMS tuning. Comparing the initially designed amplifier without MEMS, the Power Added Efficiency (PAE) of the amplifier with MEMS is improved from 46.3% to 66.9%. For the amplifier with MEMS, the nonlinear simulation results are PAE = 66.90%, $\eta$(drain efficiency) = 75.89%, and $P_{out}$ = 23.37 dBm at 8 GHz. In this paper, the concept of the MEMS tuning element is successfully applied to the Class E amplifier designed with transmission lines.