A Broadband Microstrip-Slot Coupled Radiating Structure with I-Shaped Resonators (ISRs)

A broadband I-shaped microstrip-slot coupled radiating structure with parasitic I-shaped resonators (ISRs) was presented and analyzed. Compared to previous work[1],[8], the modified new structure will have similar VSWR passband, meanwhile introduction of ISRs enhances the radiation at -z direction and suppresses the radiation at +z direction, making the radiation direction constant from 4GHz to 13.6GHz. Radiation efficiency and front-to-back ratio are also improved.