An ultrawideband (UWB) pentagon shape planar microstrip slot antenna is presented that can find applications in wireless communications. Combination of the pentagon shape slot, feed line and pentagon stub are used to obtain 124% (– GHz) impedance bandwidth which exceeds the UWB requirement of 110% (– GHz). A ground plane of 50 mm 80 mm size is used which is similar to wireless cards for several portable wireless communication devices. The proposed antenna covers only the top 20 mm or 25% of the ground plane length, which leaves enough space for the RF circuitry. Three variations of the antenna design using the straight and rotated feed lines on two different substrates. | IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION VOL. 57 NO. 5 MAY 2009 1353 Investigations on Ultrawideband Pentagon Shape Microstrip Slot Antenna for Wireless Communications Sunil Kumar Rajgopal and Satish Kumar Sharma Senior Member IEEE Abstract An ultrawideband UWB pentagon shape planar microstrip slot antenna is presented that can find applications in wireless communications. Combination of the pentagon shape slot feed line and pentagon stub are used to obtain 124 GHz impedance bandwidth which exceeds the UWB requirement of 110 GHz . A ground plane of 50 mm X 80 mm size is used which is similar to wireless cards for several portable wireless communication devices. The proposed antenna covers only the top 20 mm or 25 of the ground plane length which leaves enough space for the RF circuitry. Three variations of the antenna design using the straight and rotated feed lines on two different substrates are considered. Effect of the conducting reflecting sheet on back of the antenna is investigated which can provide directional radiation patterns but with reduced matching criteria. Finally experimental verification of the fabricated antenna for its impedance bandwidth is carried out which shows agreement with the simulated data. Index Terms Directional patterns finite ground plane microstrip line feed microstrip slot antenna omni-directional patterns reflecting sheet ultrawideband UWB . I. Introduction THE federal communications commission FCC has allocated the frequency spectrum from GHz to GHz as the ultrawideband UWB in the year 2002. Since then the UWB technology has progressed a lot and is still emerging. It has created increased interest in the UWB antennas as well. The UWB wireless communication antennas are special due to very short and low-power impulse signals which are transmitted efficiently with less distortion. Planar forms of the UWB antennas can also be integrated between the radio frequency RF front end circuitry and the .
