Design of Band-Notched Ultrawideband Square Aperture Antenna With a Hat-Shaped Back-Patch

A new square aperture antenna fed by a coplanar waveguide (CPW) is proposed for ultrawideband (UWB) applications. A corner-notched rectangular patch was printed on the backside of the substrate for enhancing the impedance bandwidth. Impedance matching for different ranges within the UWB can be easily obtained by adjusting the width and height of the back-patch, the distance from the back-patch to the lower edge of the aperture, and the size of the two notched corners in the back-patch. A rejected frequency band within the UWB was produced by embedding a pair of U-shaped slotlines in the back-patch. Measured and simulated results are presented along with simple design rules.