Design of Triple Band Slot Antenna for 802.11a/b WLAN and Upper UWB Application Using Pentagon Tuning Stub

A planar antenna with pentagon shaped tuning stub and asymmetric rectangular ground plane width along with wide rectangular aperture is presented for triple band operation. A novel concept of use of feed coupling slot as inherent band-notch at 4 GHz and design of wide rectangular aperture with length and width at λ/4 and λ of WLAN 802.11b and 802.11a resonating frequency respectively with variation in rectangular ground plane width for multiband operation is discussed. Antenna geometry is very simple and have compact dimension 32 mm × 42 mm. The operation is stable over all the operating bands centered at 2.66 GHz, 5.27 GHz and 8.78 GHz with average gain of 1.86 dBi, 0.54 dBi and 5.28 dBi respectively. The bandwidth VSWR ≤ 2 of the 802.11b, 802.11a and upper ultrawideband is 620 MHz, 860 MHz, and 3.67 GHz respectively, which corresponds to fractional bandwidth of 24.43%, 15.37%, and 32.23 %.