Broadband circularly polarized printed-spiral-strip antenna for 5-GHz WLAN operation

A novel broadband circularly polarized printed-spiral-strip antenna is presented. The antenna consists of a printed spiral strip of about 1.4 wavelengths in length wound into about one turn and mounted above a ground plane with a thick air layer. By using a 50Omega probe feed along with a long feeding strip and a coupled long-shorting strip for exciting the printed spiral strip, good circular polarization (CP) radiation over a wide bandwidth (larger than 20%) is achieved, which makes the proposed antenna well suited for applications in the 5-GHz WLAN band. Derails of the proposed antenna design and the experimental results obtained for a constructed prototype are presented. (C) 2004 Wiley Periodicals, Inc.