Compact multi-band stacked circular patch antenna for wideband applications with enhanced gain

This paper presents a probe-fed compact multi-band microstrip patch antenna for wideband operation. The proposed antenna is composed of a shorted circular patch fed by folded-patch with a V-shaped slot and two stacked circular patches. Two stacked patches with different diameters are suspended by two shorting pins above the circular patch to achieve a multi-band antenna. The proposed design without stacked patches with a folded-patch feed introduces an ultra-wideband (UWB) antenna with the measured bandwidth of 115.8% in 3.68-13.8 GHz. The proposed stacked design introduces the tuning ability of the frequency bands by changing the diameters of two stacked circular patches. The first and second measured -10 dB bands cover 3.27-4.35 GHz (28.4%) and 5.15-6.40 GHz (21.7%) for worldwide interoperability for microwave access (WiMAX) and wireless local area network (WLAN) operations, respectively. The third measured -10 dB band operates in 9.2-14 GHz with a wide impedance bandwidth (more than 41%). Likewise, good antenna performances such as broadside radiation patterns, acceptable miniaturization and high gain over the operating bands have been observed. Detailed simulations based on the parametric study are performed to identify the triple-band performance of the proposed design.