Enhanced Bandwidth of Shorted Patch Antennas Using Folded-Patch Techniques

Abstract

This letter introduces novel designs of miniaturized wideband microstrip patch antennas for ultrawideband (UWB) applications. The antennas are achieved by using folded-patch feed's techniques and shorting pins to provide the impedance bandwidths $({\rm VSWR} \leq 2)$ of 94.17% (4.13–11.48 GHz) and 98.22% (3.57–10.46 GHz), respectively. By introducing a folded ramp-shaped feed, the impedance bandwidths of the proposed antennas are considerably enhanced. Shorting pins are utilized to miniaturize the size of the patches. In the first design, unequal arms fed by a folded ramp-shaped patch produce three resonances to broaden the impedance bandwidth. Also at the second design, by adding one pin in the center of the shorted patch with a folded ramp-shaped feed, a broadband antenna is obtained. In addition, the wideband mechanism of the proposed antennas is described and discussed by investigating the effects of some key parameters.