Compact Tri-band Monopole Antenna for RFID/GPS/WLAN/WiMAX Applications

In this paper, a compact tri-band planar printed monopole antenna for the applications of RFID/GPS/WLAN/ WiMAX is proposed. The compact tri-band monopole antenna is composed of a Ψ-type monopole antenna and a circular ring ground with an arc-shaped slot. The Ψ-shaped strip can generate four resonance points to meet the low frequency coverage. An arc-shaped slot in the circular ring ground is loaded to improve high-frequency impedance matching and widen high-frequency bandwidth. The antenna is printed on a 1.6mm-thick FR-4 dielectric substrate, fed by a coaxial cable, and can provide three wide operating bandwidths that cover 0.82–0.98, 1.21–1.61 and 2.35–2.71 GHz for RFID/GPS/WLAN/ WiMAX communication systems, with S11 less than -10 dB. This compact tri-band monopole antenna is fabricated and measured, and typical experimental results such as S11, gains, and radiation patterns are presented. The measured results are dovetail with the simulated results. The advantages of the proposed antenna are compact size, simple structure, high gain and omnidirectional radiation pattern.