A proximity-fed ultra-wideband annular slot antenna with band-notch characteristics via a split-ring parasitic element

In this paper, a design of a proximity-fed planar annular slot antenna with standard band-notched characteristic for ultra-wideband (UWB) applications is demonstrated. The band-notch is realized by nearly a half-wavelength split-ring parasitic element printed around the radiating patch. The patch is excited via a proximity-fed strip line with an arrangement of EBG via holes. The voltage standing wave ratio (VSWR) of the proposed antenna is less than 2.0 in the frequency band from 2.82 to 10.74 GHz, while showing a very sharp band-rejection performance at 5.51 GHz which preserved for IEEE 802.11a and HIPERLAN/2 services. The antenna is designed, simulated, and implemented. Simulated results and measured data show good agreements. The proposed antenna provides good gain flatness, high efficiency and omnidirectional field pattern over its whole frequency band excluding the rejected band. The results show that the proposed antenna is suitable for UWB applications.