Design of the L-band Rotary Joint in Ring Contact Type to Improve Signal Insertion Loss

삽입손실 개선을 위한 링 접촉식 구조의 L대역 로터리조인트 설계

  • 나재현 (국방기술품질원 연구원) ;
  • 노돈석 ((주)엘트로닉스 연구소) ;
  • 김동길 (경일대학교 로봇공학과)
  • Received : 2018.09.19
  • Accepted : 2019.02.15
  • Published : 2019.02.28


This paper deals with the design of the L-band rotary joint, which is a core part of the tracking radar system. The rotary joint is a part that is mounted on the rotating parts of the tracking system antenna, which smoothly transmits RF signals with minimizing signal insertion loss. To improve the insertion loss of rotary joint, 1) dielectric materials, 2) design of distribution ring and 3)dielectric shape are studied. The performance of proposed rotary joint is compared with the conventional product. The prototype rotary joint showed a max insertion loss of 0.68dB, that is improved about 46% compare with conventional product which insertion loss was 1.26dB.

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그림 1. 로터리조인트의 부착 위치 및 역할 Fig. 1 Install position and role of rotary joint

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그림 2. L대역 로터리조인트의 단면도 Fig. 2 Sectional view of L-band rotary joint

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그림 3. 도입품 로터리조인트 삽입손실 측정결과 Fig. 3 Measurement result of insertion loss for rotary joint(imported)

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그림 4. 로터리조인트 설계형상 Fig. 4 Figure of rotary joint design

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그림 5. 폴리아미드 유전체를 사용한 로터리조인트의 삽입손실 시뮬레이션 결과 Fig. 5 Simulation result for rotary joint with polyamid dielectric

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그림 6. 테프론 유전체를 사용한 로터리조인트의 삽입손실 시뮬레이션 결과 Fig. 6 Simulation result in rotary joint with teflon dielectric

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그림 7. 급전분배링 형상 변경 Fig. 7 Shape change of distribution ring

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그림 8. 유전체 형상 변경 Fig. 8 Alteration of dielectric shape

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그림 9. 유전체 형상변경에 따른 시뮬레이션 결과 Fig. 9 Simulation result for different dielectric shape

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그림 10. 제안한 로터리조인트 시제 형상 Fig. 10 Prototype of proposed rotary joint

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그림 11. 제안한 로터리조인트 삽입손실 측정결과 Fig. 11 Measurement result of insertion loss for proposed rotary joint

표 1. L대역 로터리조인트 채널별 주파수 대역 Table 1. Frequency range of L-band rotary joint channel

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표 2. 로터리조인트 채널 1의 삽입손실 Table 2. Insertion loss of proposed rotary joint channel 1

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표 3. 제안한 로터리조인트 채널 2의 삽입손실 Table 3. Insertion loss of proposed rotary joint channel 2

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표 4. 로터리조인트 채널별 최대 삽입손실 비교 Table 4. Comparison of maximum insertion loss for each channel of rotary joint

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  1. D. An and J. Rhee, "Low Conversion Loss and High Isolation W-band MMIC Mixer Module," J. of the Institute of Electronics and Information Engineers, vol. 52, no. 2, Feb. 2015, pp. 232-236.
  2. K. Kim, J. Kim, and M. Bae, "The Study on the implementation and design of the RF transceiver for fast frequency hopping," J. of the Korea Institute of Electronic Communication Science, vol. 11, no. 6, June 2016, pp. 591-596.
  3. P. Wade, "Rectangular Waveguide to Coax Transition Design," QEX, Nov./Dec. 2006, pp. 10-17.
  4. C. Jung, J. Sung, J. Beak, K. Lee, C. Park, and J. Kwon, "A Study on the High-power Low-loss Dual Axes Waveguide Rotary Joint for Ka-Band Millimeter-Wave Small Radar," J. of the Institute of Internet, Broadcasting and Communication, vol. 18, no. 1, Feb. 2018, pp. 91-96.
  5. S. Kim, C. Lee, D. Han, D. Roh, and S. Kang, "The Band-Broadening Design of the Rotary Joint Transition for the X-Band Microwave Channel," J. of the Transactions of the Korean Institute of Electrical Engineers, vol. 66, no. 3, Jan. 2017, pp. 557-562.
  6. D. Bin, H. Zhang, and M. Hu, "An analysis of circular waveguide Rotary Joint design with coupling TM01 mode," Proc. of 2011 IEEE CIE International Conf. on Radar, Chengdu, China, Oct. 2011, pp. 1224-1227.
  7. A. Morini, "Design of a Dual-Band Rotary Joint Operating in X- and Ka-Bands," IEEE Transactions on Microwave Theory and Techniques, vol. 59, no. 6, June 2011, pp. 1461-1467.
  8. D. Bin and Z. Qiang, "A novel multi-channel and high-power microwave rotary joint," Proc. of the Asia-Pacific International Symp. on Electromagnetic Compatibility, Shenzhen, China, May 2016, pp. 1071-1074.
  9. J. Na, D. Roh, and D. Kim, "Fin-Line Balanced Mixer Design for Ku-band Tracking Radar Receiver," J. of the Korea Institute of Electronic Communication Science, vol. 13, no. 4, Apr. 2018, pp. 685-694.