A CPW-Fed Octagon-Shaped Aperture Antenna for Lower Band UWB Applications

A compact, CPW-fed octagon shape aperture antenna for lower band UWB applications is presented. The antenna consists of a irregular octagon (polygon with 8 sides) aperture on a printed circuit board, ground plane and a octagon-shaped exciting stub. Initially the proposed antenna is designed with rectangular aperture and then the rectangular shaped aperture is converted into irregular octagon shaped aperture by inserting a isosceles right angled triangular metallic shape in the corners of rectangular aperture to increase the impedance matching in the required bandwidth. The octagon shaped stub and polygon aperture (slot) are simple and has less parameter, which are convenient to optimize. The proposed antenna is designed on an inexpensive FR4-epoxy substrate with dielectric constant ¿
_r
=4.4 and with a size 30 mm × 30 mm × 1.5 mm.The presented antenna has a impedance bandwidth from 2.8 GHz - 4.9 GHz (VSWR<2), gain from 1.5 dBi to 3.9 dBi and directivity from 3.5 dBi to 4.4 dBi.