Design and fabrication of ultra wide-band antenna with band notching property using T-shaped defected ground structure

In this paper, a rectangular inset feed microstrip antenna with defected ground plane for UWB application is presented. It is found that by making symmetrical T-shape slots just beneath the radiating patch in the ground plane results UWB characteristics. Parasitic effect is minimized by optimization in the shape of slot like width and length, so that uniform return loss is obtained in the entire UWB range. The simulated and fabricated antenna design shows return loss below -12 dB and voltage standing wave ratio below 2 in the entire UWB range. A very wide impedance bandwidth of 11.2 GHz at -10dB return loss has been obtained. Further, band notching property to avoid the signal interference from existing WiMax system in the environment has been obtained by varying ground structure. The effect of first T-cut slot in ground structure has been observed to result band notching from 3.28 to 4.58 GHz. Therefore, the proposed antenna overcomes the signal interference problem with existing WiMax IEEE 802.16 system and can be suitably used for UWB application.