Design of GaAs FET Linearizer with Variable Source Inductance

가변 소스 인덕터를 갖는 GaAs FET 선형화기 설계

  • Published : 1999.12.01

Abstract

In this paper, a new type of predistortion linearizer has been studied. It employs a series feedback amplifier with a large source inductance as a predistortion linearizer, which provides positive amplitude and negative phase deviations for input Power and can compensate for AM-AM and AM-PM distortions of power amplifier. This predistortion lineariaer consists of only one CaAs FET, large source inductor, input output matching networks and bias circuits. Because of its simple circuit, the linear can be operated over a broad bandwidth and has good thermal stability The characteristics of this linearizer can be easily tuned using source inductor, its gate bias condition. In fabricated linearizer, the third-order intermodulation distortion(IMD) for main amplifier alone is 10.61dBc, and the $IM_3$ for main amplifier with predistorter is 21.91dBc. Therefore, the $IM_3$ characteristic results an improvement of approximately 11dB.

본 논문에서는 소스에 큰 값의 가변 인덕터를 갖는 새로운 형태의 predistortion 선형화기가 연구되었다. 그것은 입력 전력이 증가함에 따라 양의 진폭과 음의 위상 편차를 얻을 수 있어 전력증폭기에서 만들어지는 왜곡을 충분히 보상할 수 있다. 또한, 하나의 CaAs FET, 인덕터, 입 출력 정합회로, 그리고 바이어스회로로 구성되어, 회로가 간단하므로 넓은 대역폭에 걸쳐 선형화 특성과 온도 안정성을 갖는다. 그리고 소스 인덕터와 게이트 바이어스를 변화시킴으로써 원하는 왜곡 특성을 얻을 수 있는 장점을 갖는다. 제작한 predistorter에서, 주 증폭기에 의한 IM3가 10.61dBc이고, predistorter를 갖는 주 증폭기의 IM3가 21.91dBc이므로 약 11dB의 개선된 결과를 얻었다.

Keywords

References

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