The Journal of Korean Institute of Electromagnetic Engineering and Science (한국전자파학회논문지)

The Korean Institute of Electromagnetic Engineering and Science (한국전자파학회)
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Design Technique Using Bypass Capacitor to Improve Antenna Efficiency of Inverted-F Antenna with Band Stop Matching Circuit

Band Stop Matching Circuit이 적용된 Inverted-F Antenna의 Bypass Capacitor를 이용한 안테나 효율 향상 기법

  • Bae, Jang Hwan (Department of Electrical Electronic Engineering, Yonsei University) ;
  • Choi, Woo Cheol (Department of Electrical Electronic Engineering, Yonsei University) ;
  • Lim, Seonho (Department of Electrical Electronic Engineering, Yonsei University) ;
  • Yoon, Young Joong (Department of Electrical Electronic Engineering, Yonsei University)
  • 배장환 (연세대학교 전기전자공학과) ;
  • 최우철 (연세대학교 전기전자공학과) ;
  • 임선호 (연세대학교 전기전자공학과) ;
  • 윤영중 (연세대학교 전기전자공학과)
  • Received : 2017.01.24
  • Accepted : 2018.12.07
  • Published : 2019.01.31
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Abstract

In this paper, a design technique using a bypass capacitor is proposed to improve the antenna efficiency of an inverted-F antenna (IFA) with a band stop matching circuit (BSMC). The proposed antenna operates in the LTE bands 26 and 5(814~ 894 MHz). The bandwidth of the IFA is expanded from 803~863 MHz to 800~888 MHz using the impedance change caused by the BSMC. To enhance the antenna efficiency in the expanded frequency band, the bypass capacitor is applied to the IFA with the BSMC. The bypass capacitor improves the efficiency of the antenna by reducing the current variation of the IFA with the BSMC. The proposed antenna has a bandwidth of 804~895 MHz and the antenna efficiency increases by more than 10 % in the extended frequency band by using the bypass capacitor.

본 논문에서는 bypass capacitor를 이용하여 Band Stop Matching Circuit(BSMC)을 적용한 Inverted-F Antenna(IFA)의 효율을 향상 기법을 제안한다. 본 논문에서 설계한 안테나의 동작주파수는 LTE band 26과 5(814~894 MHz) 대역이다. BSMC의 임피던스 변화를 이용하여 IFA의 대역폭을 -6 dB 기준 823~886 MHz에서 800~888 MHz로 확장하였다. 확장된 주파수 대역에서 안테나의 효율을 향상시키기 위해 BSMC가 적용된 IFA에 bypass capacitor를 적용하였다. Bypass capacitor는 BSMC가 적용된 IFA의 전류 변화량를 감소시켜 안테나의 효율을 향상시켜주는 역할을 한다. Bypass capacitor를 적용시켰을 때 대역폭은 804~895 MHz이며 확장된 주파수 대역에서 안테나 효율은 10 % 이상 증가하였다.

Keywords

JJPHCH_2019_v30n1_1_f0001.png 이미지

그림 1. BSMC를 적용한 IFA Fig. 1. IFA with BSMC.

JJPHCH_2019_v30n1_1_f0002.png 이미지

그림 3. IFA와 BSMC을 적용한 IFA의 임피던스 차트 시뮬레이션 결과 Fig. 3. Simulated result of impedance chart of proposed IFA with BSMC and without BSMC.

JJPHCH_2019_v30n1_1_f0003.png 이미지

그림 2. BSMC의 S(2,1) parameter 시뮬레이션 결과 Fig. 2. S(2,1) parameter of BSMC.

JJPHCH_2019_v30n1_1_f0004.png 이미지

그림 4. IFA와 BSMC을 적용한 IFA의 반사계수 측정 결과 Fig. 4. S(1,1) measurement results of IFA and IFA withBSMC.

JJPHCH_2019_v30n1_1_f0005.png 이미지

그림 5. Bypass capacitor를 적용한 임피던스 정합회로 Fig. 5. Impedance matching circuit with bypass capacitor.

JJPHCH_2019_v30n1_1_f0006.png 이미지

그림 6. BSMC와 bypass capacitor를 적용한 IFA의 815 MHz에서 전류분포 Fig. 6. Current flow of IFA with BSMC and bypass capa-citor at 815 MHz.

JJPHCH_2019_v30n1_1_f0007.png 이미지

그림 7. 815 MHz에서 BSMC을 적용한 IFA의 전류분포 Fig. 7. Current flow of IFA with BSMC at 815 MHz.

JJPHCH_2019_v30n1_1_f0008.png 이미지

그림 8. Bypass capacitor 값에 따른 반사 계수 선도 시뮬레이션 결과 Fig. 8. Simulated S(1,1)-parameters according to bypass ca-pacitor value.

JJPHCH_2019_v30n1_1_f0009.png 이미지

그림 9. 제작한 BSMC와 bypass capacitor를 적용한 IFA Fig. 9. Fabricated IFA with BSMC and bypaas capacitor.

JJPHCH_2019_v30n1_1_f0010.png 이미지

그림 10. IFA, BSMC을 적용한 IFA, BSMC와 bypass capacitor를 적용한 IFA의 반사계수 측정 결과 Fig. 10. S(1,1) measurement results of IFA and IFA with BSMC.

JJPHCH_2019_v30n1_1_f0011.png 이미지

그림 11. 확장된 주파수 대역에서 BSMC를 적용한 IFA와 BSMC와 bypass capacitor를 적용한 IFA의 안테나 효율과 이득 측정 결과 Fig. 11. Antenna Efficiency and gain measurement results of IFA with BSMC and IFA with BSMC and bypass capacitor in the expanded frequency band.

JJPHCH_2019_v30n1_1_f0012.png 이미지

그림 12. BSMC를 적용한 IFA와 BSMC와 bypass capacitor를 적용한 IFA의 원거리장 패턴 측정 결과 Fig. 12. Measured far-field pattern of IFA with BSMC and IFA with BSMC and bypass capacitor.

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