A CPW-fed wideband spiral slot antenna with circular polarization.

A new design of broadband slot antenna with circular polarization is presented. The broadband characteristics are achieved using a coplanar-waveguide (CPW)-fed two-arm spiral slot configuration. The spiral slot antenna and the feeding structure are fabricated on the same plane of the substrate so that the circuit process and the position alignment could be simplified. The improvement of circular polarization for the antenna is obtained mainly by an arc slot surrounding the spiral slots. The turn number of the spiral slots and the geometrical dimensions of the arc slot are varied in order to derive the better performance of the circular polarization. The measured impedance bandwidth of a S11 < -10 dB ranges from 1.25 to 8 GHz and covers most of the commercial wireless communication systems, such as GPS, DCS, PCS, IMT-2000, WLAN, and HiperLAN. The measured 3-dB axial-ratio bandwidth (ARBW) is 10.6% with respect to 1.605 GHz. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1204–1208, 2010; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/mop.25142 [ABSTRACT FROM AUTHOR]