Design of a compact ultra-wide-band monopole antenna with band rejection characteristics

This study presents a design of two compact monopole antennas with band-notched characteristics for ultra-wide-band application. The compact antennas are etched on an FR4 substrate with the size of 14 × 16 × 1 mm³, consists of a tree-shaped radiation patch with modified ground structure, providing a wide usable fractional bandwidth of more than 170% (2.8-19.2 GHz). To reject certain-frequency bands, two completely different approaches are proposed. First a shorted T-shaped quarter-wavelength resonator is used to omit undesired frequency band of 5.1-5.9 GHz. In the second approach, two L-shaped slots are inserted in the patch to act as a filter structure for worldwide interoperability for microwave access (3.4-3.6 GHz) and wireless local area network (5-5.6 GHz) applications. The band-notched can be controlled by adjusting the length of the rectangle slots. The effects of dimensional parameters on the antenna performance have been investigated through a parametric study. Furthermore, current density distribution on the antenna is also computed to gain a better insight of its behaviour. The antennas are investigated numerically and experimentally for their impedance matching properties, frequency notched characteristics and radiation performances.