Multimode electric ring resonator (ERR) for ultra-wideband (UWB) antenna with multi-notch band

The electric ring resonator (ERR) is widely used for a design of metamaterials. The planar multimode ERR is considered as a promising structure for a design of multiband microwave devices. The ultra-wideband (UWB) planar antenna with multi-notch band is designed as a circular metallic patch fed by a coplanar waveguide (CPW) loaded with the ERR. To achieve the notched characteristics at desirable frequencies, the multimode ERR is incorporated into the CPW feedline of the planar UWB antenna. The notched frequency band is controlled by dimensions of the ERR structure. The antenna demonstrated a VSWR lower than 2.5:1 and consistent monopole-like, omnidirectional radiation patterns over a 4.8:1 bandwidth. A prototype of the antenna with physical dimensions of 50 x 50 x 1.52 mm demonstrates multi notch characteristic at 3.5, 5.8, and 7.5 GHz in the 2.5-12 GHz frequency range