EBGs are arranged in this way to achieve better return loss. Dimension of the
antenna and EBG is 143 £ 136mm2. Simulated Return loss is ¡40:68 dB and axial ratio is 2.6 dB
at 2.45 GHz. So an improvement in return loss and axial ratio is found. We consider via's radius
r = 0:025mm and use Transmission theory for EBG structure. Figure 4(b) shows this layout,
now EBG gap is 0.16 mm. Return loss improvement is not as high as in previous cases because
of via's radius consideration. Consideration of via's radius is more realistic and practical. In this
case return loss and axial ratio is ¡31:2 dB and 2.8 dB respectively. Dimension is 167 £ 166mm2
for antenna and EBG. From Figure 6, we see some backward radiation in radiation pattern of the
antenna, these is due to the presence of EBG structure. This simulated antenna can be a suitable
one for 2.4 GHz band WLAN system.