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 planes, and can easily be controlled by the perimeters of outer and inner rectangular‐slot loops in the proposed antenna. The two rectangular‐slot loops are both capacitively fed by a 50 Ω coplanar waveguide, and good impedance matching for the two operating frequencies with a frequency ratio ranging 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 two frequencies are obtained.