Journal of the Korea Academia-Industrial cooperation Society (한국산학기술학회논문지)

The Korea Academia-Industrial cooperation Society (한국산학기술학회)
권호 표지
DOI QR코드

DOI QR Code

CPW-fed Compact Slot Antenna Matched by T-shaped Stub

T형 스터브로 정합된 CPW급전 소형 슬롯 안테나

  • Lee, Jong-Ig (Department of Electronics Engineering, Dongseo University) ;
  • Yeo, Jun-Ho (School of Computer and Communication, Daegu University)
  • Received : 2012.04.09
  • Accepted : 2012.07.12
  • Published : 2012.07.31
Download PDF
⟨ Previous Next ⟩

Abstract

In this paper, a design method for a compact slot antenna fed by a coplanar waveguide (CPW) is studied. A T-shaped tuning stub is inserted inside a narrow rectangular slot and the slot is impedance matched to the CPW feedline by adjusting the width, length, and position of the stub. The resonance frequency is adjustable by the slot length and the antenna size can be reduced by bending the slot. The resonance frequency and impedance matching property of the compact slot antenna are similar to those of the half-wavelength slot antenna, which enables one to design compact antenna of this type with ease. A compact slot antenna for 2.45-GHz ISM band is designed, fabricated on an FR4 substrate (dielectric constant of 4.4 and thickness of 0.8 mm), and experimentally tested. The measured results agree well with the simulations, which confirms the validity of this study. The fabricated compact slot antenna shows an impedance bandwidth of 200 MHz(2.32-2.52 GHz) for a VSWR < 2, which is suitable for 2.45-GHz ISM band (2.4-2.48 GHz). The measured radiation patterns show ${\infty}$-shaped directional pattern in the E-plane and nearly omni-directional pattern in the H-plane with a peak gain of 2.0 dBi, which are similar to those of a monopole antenna. The proposed antenna is expected to be suitable for the applications as antennas for WLAN, RFID, and mobile handset.

본 논문에서는 코프래너 도파관(CPW)으로 급전된 소형 슬롯 안테나 설계방법에 대하여 연구하였다. 폭이 좁은 직사각형 슬롯에 삽입된 T형 튜닝 스트립의 위치, 폭, 길이를 조절하여 슬롯 안테나와 CPW 급전선이 임피던스 정합되도록 하였다. 슬롯의 길이 변화로 공진 주파수를 조절할 수 있고, 슬롯을 구부려서 소형화할 수 있다. 소형 슬롯 안테나의 공진 주파수와 임피던스 특성이 반 파장 슬롯 안테나와 비교하여 큰 변화가 없으므로 소형화 설계가 용이하다. 2.45 GHz ISM 대역용으로 소형 슬롯 안테나를 설계하고, FR4 기판(비유전율=4.4, 두께 0.8 mm) 상에 제작한 후 특성을 실험하였다. 측정된 결과들은 시뮬레이션과 잘 일치하여 본 연구의 타당성을 검증하였다. 제작된 소형 슬롯 안테나의 정재파비(SWR)가 2이하인 대역폭은 200 MHz(=2.32-2.52 GHz)로서 ISM 대역(2.4-2.48 GHz)용으로 적합하다. 측정된 복사패턴은 모노폴과 유사하게 E-면에서 8자형 지향성 패턴을 보이고, H-면내에서는 거의 무지향성 패턴을 보이며, 이득은 2.0 dBi 이므로 무선 랜, RFID, 휴대단말기용 안테나 등으로 응용이 적합할 것으로 기대된다.

Keywords

References

  1. R. Garg, et. al., Microstrip antenna design handbook. Boston, Artech House, 2001.
  2. M. K. Kim, K. Kim, Y. H. Suh, and I. Park, "A T-shaped microstrip-line-fed wide slot antenna," Proc. IEEE Antennas and Propag. Soc. Int. Symp, vol. 3, pp. 1500-1503, July 2000.
  3. H. D. Chen, "Broadband CPW-fed square slot antennas with a widened stub," IEEE Trans. Antennas Propag., vol. 51, no. 8, pp. 1982-1986, Aug. 2003. https://doi.org/10.1109/TAP.2003.814747
  4. A. A. Gheethan and D. E. Anagnostou, "Broadband and dual-band coplanar folded-slot antennas (CFSAs)," IEEE Antennas and Propagation Magazine, vol. 53, no. 1, pp. 80-89, Feb. 2011. https://doi.org/10.1109/MAP.2011.5773572
  5. S. -Y. Chen and P. Hsu, "CPW-fed folded-slot antenna for 5.8 GHz RFID tags," Electron. Lett., vol. 40, no. 24, pp. 1516-1517, Nov. 2004. https://doi.org/10.1049/el:20046780
  6. Y. -F. Lin, et. al., "CPW-fed capacitive H-shaped narrow slot antenna," Electron. Lett., vol. 41, no. 17, pp. 940-942, Aug. 2005. https://doi.org/10.1049/el:20051571
  7. D. Ma and W. X. Zhang, "Broadband CPW-fed RFID antenna at 5.8 GHz," Electron. Lett., vol. 42, no. 22, pp. 1258-1259, Oct. 2006. https://doi.org/10.1049/el:20062595
  8. X. Hu and Q. Zhang, "Compact slot antenna for 2.4GHz RFID tags," Proc. EuCAP, pp. 2796-2798, 2009.
  9. P. Selvan and S. Raghavan, "CPW-fed folded spiral strip monopole slot antenna for 5.8 GHz RFID application," Proc. AEMC, pp. 1-3, 2009.
  10. C. Yu and X. Liu, "A wideband single chip inductor-loaded CPW-fed inductive slot antenna," IEEE Trans. Antennas Propagat., vol. 56, no. 5, pp. 1498-1501, May 2008. https://doi.org/10.1109/TAP.2008.919224
  11. Y. Yoshimura, "A microstripline slot antenna," IEEE Trans. Microwave Theory Tech., vol. 20, no. 11, pp. 760-762, Nov. 1972. https://doi.org/10.1109/TMTT.1972.1127868
  12. J. P. Kim and W. S. Park, "Network modeling of an inclined and off-center microstrip-fed slot antenna," IEEE Trans. Antennas Propag., vol. 46, no. 8, pp. 1182-1188, Aug. 1998. https://doi.org/10.1109/8.718573