Guidance and absorption of internal energy in Vivaldi antennas using multiple slots, full-band dividers, metamaterials, and distributed resistors

In traveling-wave planar-technology antennas, only a certain portion of excitation energy contributes to expected radiation. The remaining significant portion, referred to as residual electromagnetic (EM) energy, has negative effects on overall antenna performance. A systematic design methodology to mitigate such degradation is presented in this paper. The design approach is based on an analysis of structural scattering and radiation mechanism, supported by near-field and partition far-field characterizations. The design process involves the arrangement of primary antenna scattering sections into a form of multi antipodal Vivaldi slots; the identification of desired and undesired EM flows of internal EM energy; the adjustment of radiation flows using inhomogeneous metamaterial structures; and the guidance and absorption of residual energy through dissipation paths with distributed resistors. The effectiveness of the method is demonstrated by the high-gain and wideband antenna performance. Additionally, novel full-band power dividers are proposed to efficiently feed both individual antenna and array.