Investigation of Compact Near-Equidistant Multimode Resonator Integrating Skyrmionic Metamaterial With SIW Cavity and Its Application in Dielectric Material Detection

In this article, a novel compact near-equidistant multimode resonator that integrates skyrmionic metamaterial (SM) with a substrate integrated waveguide (SIW) cavity is proposed. This planar SM-SIW cavity resonator can generate various microwave skyrmion modes, effectively demonstrating the feasibility of the cavity excitation and integration design for the microwave SM structure. Furthermore, the electromagnetic coupling characteristics of asymmetrical SM-SIW cavity resonators are investigated, revealing that each skyrmion mode of the resonator significantly splits into two distinct resonant modes, affected by both distance and permittivity. Leveraging these features, a novel microwave meta-sensor based on coupled SM-SIW cavity resonators is developed for dielectric material detection. This meta-sensor can perform both permittivity and thickness measurements, which are achieved by monitoring shifts in resonant frequencies and variations in splitting degrees across various modes, respectively. To enhance the dual-functional detection capabilities of the meta-sensor, an effective microwave spectral identification method (MSIM) is presented to synthesize sensing results from multiple modes. A prototype of the meta-sensor is fabricated and tested to validate its effectiveness. Experimental results demonstrate that the proposed meta-sensor can effectively monitor variations in both the permittivity and thickness of dielectric materials across different modes, with high sensitivities of 123.5 MHz/( $\Delta \varepsilon _{r} =1$ ) and 517.8 MHz/mm, respectively.