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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)
  • 이종익 (동서대학교 전자공학과) ;
  • 여준호 (대구대학교 정보통신공학부)
  • Received : 2012.04.09
  • Accepted : 2012.07.12
  • Published : 2012.07.31

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.

Keywords

Slot antenna;Compact antenna;T-shaped tuning stub;CPW-fed antenna;Center-fed slot antenna

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