Triple band patch antenna for Wibro/WLAN applications using a CRLH unit cell

A patch antenna with multiple resonance modes is presented. The proposed antenna is loaded with a composite right/left-handed (CRLH) unit cell which is composed of a gap capacitor in the patch and a complementary split-ring resonator (CSRR) slot on the ground plane. The CRLH unit cell provides a dual band operation at the zeroth- and the first-order resonances. The first-order resonance frequencies can be modified by changing the series capacitance while the zeroth-order resonance frequency is determined by the equivalent inductance and capacitance values of the CSRR slot. Additional resonance at 5.8 GHz WLAN band is obtained by inserting a shunt stub of λ/2. The proposed antenna provides triple-band resonances at Wibro, 5.2 GHz WLAN, and 5.8 GHz WLAN bands. Moreover, the electrical size of the patch is only 0.05 λ0 × 0.14 λ0.