Miniaturized Wideband Metasurface Antennas Using Cross-Layer Capacitive Loading

One kind of cross-layer capacitive-loaded metasurface (MS) structure is proposed and applied to realize miniaturized wideband MS antennas. The proposed MS structure is constructed by loading a thin substrate with several stacked patches above conventional MS structure, where the cross-layer stacked patches are located upon the gaps between the original MS units. Therefore, additional capacitances can be introduced accordingly, and then help decrease the resonance frequency effectively. Based on above strategies, when the resonance frequency remains unchanged, the proposed MS structure with smaller aperture size can provide equivalent capacitive reactance and inductive reactance with conventional MS structure. In this way, the miniaturization can be realized while the wideband feature is still remained. By optimizing the loading structure, symmetrical and asymmetrical MS structures are designed accordingly and different-level miniaturizations are realized, where the element sizes can be respectively miniaturized to 0.067
λ
₀
× 0.067
λ
₀
and 0.059
λ
₀
× 0.059
λ
₀
. For demonstration, onw asymmetrical capacitive-loaded MS structure is used to realize a compact wideband MS antenna, where large impedance bandwidth (∼44.4%) and compact size (∼0.41
λ
₀
× 0.41
λ
₀
) are obtained. This design method may provide a feasible solution to realize compact wideband MS antennas for broadband wireless communication systems.