Miniaturised UWB antenna with dual-band rejection of WLAN/WiMAX using slitted EBG structure

This study presents a new slitted electromagnetic bandgap (EBG) structure to filter undesired wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) bands in the ultra-wideband (UWB) spectrum. A simple UWB antenna which consists of a microstrip tapered feed line, a circular patch and a defected ground structure is used as a reference antenna. The antenna is then integrated with a slitted EBG structure near the feed line to notch two interfering bands. The created notched bands by the EBG structure can be independently controlled. Owing to structural symmetry of the proposed antenna, the size can be reduced by approximately half to form a miniaturised antenna. The miniaturised antenna has the same full-size antenna characteristics with little change in the notched bands specifications. Frequency domain measurement results show that the full-size and miniaturised antennas have a flat transfer function, and a group delay variation of about 0.5 ns in the entire UWB band except for the notched bands.