A miniaturized monopole antenna for ultra-wide band operation

This study firstly investigates a printed rectangular monopole antenna with notched ground plane. The planar monopole was printed on an FR4 substrate and placed above a rectangular notch cut in a finite ground plane edge. By suitable separations of the patch from the left and right edges of the notch, two derived resonant modes are added to the lower band and upper bands respectively. Therefore, the impedance bandwidth of the proposed antenna is significantly widened. In addition, the separation of the patch from the notch bottom edge obviously increases the input impedance in lower band, and shifts the operating band toward lower frequency. All the mentioned effects reduce the resonant path length from 0.25lambda_g to 0.2lambda_g at the lowest operating frequency and enhance the impedance bandwidth to 104%. The design is particularly described in this paper, and experimental results of the constructed prototype for the requirement of IEEE 802.16e are presented are presented and discussed.