Studies of a CPW-fed dual-frequency annular-ring slot antenna

Annular-ring slot antennas have become of great interest. Printed slot antennas fed by a coplanar waveguide have several advantages that include lower radiation losses, wider bandwidth, better impedance matching, and easier integration of solid-state devices. We propose a novel simple design of a dual-frequency annular-ring slot antenna fed by a coplanar waveguide. The antenna consists of two concentric annular-ring slot antennas; the antennas are coupled to each other and excited by the same feed. The two resonant frequencies of the antenna are separately decided by the circumferences of the two annular-ring slot antennas. Also, the two operating frequencies are found to have the same polarization planes and similar broadside radiation characteristics. Designs of the proposed antennas are described and typical experimental results are presented and discussed.