Tri-band notched ultra-wideband antenna using capacitively loaded loops (CLLs)

There are several methods with which one can achieve a band-notched UWB antenna. The most popular approach to introduce such a band-notched function is to embed slots or slit into the radiator or its ground plane. A. 5.2 GHz band-notched UWB antenna using a slot-type split ring resonator (SRR) has been proposed. In this paper, a novel way is proposed to design a triband-notched UWB antenna by utilizing capacitively-loaded loops (CLLs). Each CLL element has a high-Q characteristic, in addition to its compact size, making them very suitable for band-stop filter functions. Like the SRR element, the CLL element is self-resonant, the resonant frequency being determined mainly by the loop inductance and the capacitance resulting from cuts in the loop. However, the CLL element has a much simpler design. Different CLLs are placed on both sides of the feeding line to control the band-notched frequencies, as well as to minimize their space requirements. By tuning the sizes of the CLL elements, tri-band-notched functionality can be easily obtained.