Single-shot near-field reconstruction of metamaterial dispersion

TL;DR

This paper introduces a rapid, single-measurement near-field technique for reconstructing the dispersion relations of microwave metamaterials, enabling efficient analysis without multiple measurements or averaging.

Contribution

The method allows for single-shot near-field measurement and dispersion reconstruction of metamaterials, providing a new efficient approach for analyzing spatially dispersive materials.

Findings

Successfully reconstructed hyperbolic isofrequency surface of wire metamaterial

Accurately captured low-frequency dispersion characteristics

Provided a practical tool for near-field metamaterial analysis

Abstract

We present a single-shot near-field technique, where the near-field scan is performed on a single sample without repeating measurements or averaging over multiple samples, to reconstruct the isofrequency surfaces of metamaterials in the microwave regime. In our approach, we excite resonant modes using a fixed source in a resonator composed of the material under test and map the in-plane field distribution with a movable probe. Applying a fast Fourier transform (FFT) to the measured field reveals the sample's in-plane dispersion. By extending this analysis over multiple frequencies and comparing the results with Fabry-P\'erot resonances, we retrieve the full three-dimensional dispersion relation. When we apply the method to a double non-connected wire metamaterial, it accurately captures the low-frequency hyperbolic isofrequency surface, providing both a precise experimental tool and conceptual insight into spatially dispersive metamaterials.