Dual-frequency operation of a coplanar waveguide-fed dual-slot loop antenna

This paper proposes a novel dual-frequency coplanar waveguide-fed dual-slot loop antenna. The two operating frequencies have the same polarization pla nes, and can easily be controlled by the perimeters of outer and inner rect angular-slot loops in the proposed antenna. The two rectangular-slot loops are both capacitively fed by a 50 Omega coplanar waveguide, and good impeda nce matching for the two operating frequencies with a frequency ratio rangi ng from about 1.33 to 1.54 can be achieved. Also, wide operating bandwidths (13.6-17.8% for the lower band and about 7% for the higher band) for the t wo frequencies are obtained. (C) 2001 John Wiley & Sons, Inc.