Journal of Advanced Navigation Technology (한국항행학회논문지)

The Korean Navigation Institute (한국항행학회)
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Linear Characteristics Improvement of X-band TWT Amplifier for Satellite Communication with Linearizer

선형화기를 이용한 위성통신용 X-밴드 TWT 증폭기 선형특성 개선

  • Received : 2011.10.05
  • Accepted : 2011.10.30
  • Published : 2011.10.31
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Abstract

This paper has analyzed the AM-AM and AM-PM characteristics of 7.9 GHz~8.4 GHz X-band TWT used for satellite communication and improved its linearity and IMD performance by using linearizer. The TWT amplifier with the linearizer shows better AM-AM and AM-PM conversion, and has increased 1 dB compression point by 12.3 dB and $2.0^{\circ}/dB$ phase distortion point by 10 dB. The 3rd order intermodulation distortion, IMD3 is measured to be 37.0 dBc that is 16.2 dB improvement at the operating output. This paper also proposed the measurement method of IMD for high power amplifier, and that TWT amplifier can have better linearity and output power by compensating for the AM-PM characteristics.

본 논문에서는 7.9 GHz~8.4 GHz 에서 동작하는 위성통신용 X-밴드 TWT의 AM-AM과 AM-PM 변환특성을 분석하고 선형화기를 이용하여 선형성과 IMD 특성을 개선하였다. 선형화기를 포함하는 TWT는 개선된 AM-AM과 AM-PM 변환특성을 나타내며, 1 dB 압축점은 12.3 dB, $2.0^{\circ}/dB$ 위상왜곡점은 10 dB 개선되었다. 또한 동작출력에서 3차 상호변조 특성인 IMD3는 16.2 dB 개선되어 37.0 dBc로 측정되었다. 또한, 고출력 증폭기의 IMD 측정 방안을 제시하고, TWT의 AM-PM 왜곡 특성을 보상하여 출력전력과 선형 특성을 개선할 수 있음을 나타내었다.

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References

  1. Jan M. Weekley, Bill J. Mangus, "TWTA versus SSPA: A comparison of on-orbit reliability data," IEEE Trans. on Electron Devices, vol.52, no.5, pp.650-652, May 2005. https://doi.org/10.1109/TED.2005.845864
  2. Allen Katz, "TWTA linearization," The Microwave Journal, vol. 39, no.4, pp.78-90, April 1996.
  3. Steve C. Cripps, RF power amplifier for wireless communication, Artech House, 2006.
  4. Xin Hu, Gang Wang, Zi-Chen Wang, and Ji-Run Luo, "Predistortion linearization of an X-band TWTA for communications applications," IEEE Trans. on Electron Devices, vol. 58, no.6, pp. 1768- 1774, June 2011.
  5. K. Kanto, A Satomi, Y. Asahi, Y. Kashiwabra, Y. Matsushita, K. Takagi, "An X-band 250W solid-state power amplifier using GaN power HEMTs," IEEE Radio and Wireless Symposium, pp.77-80 Jan. 2008.
  6. Ji Han Joo, Min Ho Son, Yong Dug Lee, Jin Joo Choi, "Feedfoward and predistortion linearizers on an X-band helix TWT," IEEE International Vacuum Electronics Conference, pp. 174-175, April 2004.