An octagonal ultra-wideband double slit antenna for WiMAX and WLAN rejection
Abstract This article proposes a dual band rejected double slits-based planar octagonal microstrip antenna for Ultra-Wideband (UWB) applications. The antenna built by an edge trimmed partial ground and an octagonal microstrip patch with a horizontal and an inclined rectangular slit. The slits are made to remove the interfering frequency bands WiMAX and WLAN from UWB band. The designed antenna without slits operates on the frequency range 2.78–10.78 GHz with a fractional bandwidth of 119% which includes the UWB frequency band 3.1–10.6 GHz. The antenna with diagonal inclined slit notches the band 4.4–5.83 GHz which excluded WLAN frequency range and shift the starting frequency of UWB band to the right from 2.78 to 3.26 GHz. The antenna with both horizontal and inclined slits further shifts the starting frequency from 3.26 to 3.619 GHz, eliminating the WiMAX band. The excluded bands show the VSWR value greater than 2 dBi whereas the rest of the band has less than 2 dBi. The proposed antenna results in nearly omnidirectional radiation pattern, 6.2 dBi peak gain and 85% radiation efficiency.