In-phase reflection and EM wave suppression characteristics of electromagnetic band gap ground planes

The reflection phases of incident plane waves on EBG surfaces are found and compared for mushroom-like EBG and UC-EBG structures. It is noticed that the in-phase reflection phase occurs at a lower frequency for mushroom-like than the UC-EBG for the same cell size. A suspended stripline over an EBG ground plane is used to model the EM wave suppression characteristics of EBG structures. The drop in S21 shows a clear band gap for EM wave suppression; however this region does not match with the resonant frequency of the normal incident for the mushroom like structure because of the dependence of resonant frequency on polarization and angle of the incident wave. It is found that the resonant frequency of an obliquely incident TM matches well with the band gap result of the suspended strip.