T-like Modified Dumbbell-shaped EBG Structure for Multiband Bandstop Performance

In this article, a modified dumbbell-shaped electromagnetic bandgap structure is presented that exhibits multiband bandstop performance at different microwave frequencies in the range of 3 GHz to 17 GHz. Four stop-bands are formed: the first two are in the unlicensed radio application frequency band (3.1–10.6 GHz), the third one is in the X-band (8–12 GHz), and the fourth one is in the Ku-band (12–18 GHz). Besides, the stop-band and pass-band widths, insertion loss, and return loss are very attractive.