Design of Sharp Roll-Off Band Notch With Fragment-Type Pattern Etched on UWB Antenna

Fragment-type etch patterns are proposed and designed on an ultrawideband planar antenna to acquire sharp roll-off band notch. Multiobjective evolutionary algorithm is applied to achieve the optimization searching of the best fragment-type etch pattern by setting multiple objectives to acquire the exact notched band and challenge the roll-off criterion (ROC) of band notch. Efficiency of the design can be improved by properly presetting slits on the patch radiator. For demonstration, designs with different slit presetting are implemented and tested. With single slit preset, the band notch of ROC = 0.72 at the wireless local area networks (WLAN) band ranging from 5.15 to 5.85 GHz is acquired.