CPW-Fed Double Circular Ring Slot Wideband Antenna for WLAN/WiMAX Applications

In this paper, a wideband coplanar waveguide (CPW)-fed double circular ring slot (DCRS) antenna is presented. This antenna consists of a DCRS with an extended ground plane to achieve wider impedance bandwidth and excited by a 50 Ω CPW feedline. A prototype is fabricated and the dimensions merely 0.306 × 0.343 × 0.015λ
³
_L0
, λ
_L0
is the wavelength in free space at the lowest operating frequency (i.e., 2.86 GHz). The measured impedance bandwidth is nearly similar to the simulated results is about 95.3 % (from 2.86 to 8.06 GHz) (S
₁₁
<; -10 dB). Suitable combinations of an extended ground plane and a pair of circular ring slot on the rectangular patch, a wider impedance bandwidth is achieved. Simulated voltage standing wave ratio (VSWR) <; 2 is achieved entire band of frequency operation. Meanwhile, the proposed antenna simulation radiation patterns result in an exhibit almost omnidirectional.