Quad band-notched ultrawideband antenna with a modified H-shaped resonator

In this study, a novel planar ultrawideband antenna, with a quad band-notched function, is investigated. The proposed antenna consists of a circular-shaped radiating element, a 50 microstrip feed line, a modified H-shaped resonator, and a partially truncated ground plane. The proposed H-shaped resonator, with quadruple resonance characteristics, is realised without any change in its size but instead, by modifying the simplified composite right/left-handed resonator with dual resonance characteristics. By embedding the modified H-shaped resonator beside the microstrip feedline, band-rejected filtering properties in the wireless local area network /worldwide interoperability for microwave access bands are generated. By changing the modified H-shaped resonator's dimensions, the proposed antenna shows variable quadplex-filtering characteristics, such as band-notch frequency and its bandwidth. The measured results show that the proposed antenna design exhibits a 10 dB return loss bandwidth from 2.12 to 13.63 GHz, excluding the rejection bands. Very sharp notch and high band-rejection are achieved, and relatively stable omnidirectional radiation performance over the entire frequency range is also obtained.