Experimental realization of a discrete -space angular filter in microwave networks
Phys. Rev. Applied 25, 064043 – Published 10 June, 2026
DOI: https://doi.org/10.1103/yv76-8rw6
Abstract
We experimentally realize an angular filter using a microwave network of coaxial cables, guided by the theoretical framework of quantum graphs with beyond-nearest-neighbor coupling. Our setup implements a resonant metamaterial interface that selectively transmits waves only at discrete output directions. The experimental results confirm the presence of angular filtering predicted in quantum graph models. A signal introduced at one side of a finite square lattice network is transmitted through the filter only along certain directional components at specific frequencies. The effect is caused by a resonance-induced switching of boundary conditions at the filter interface. Our findings validate theoretical predictions and demonstrate the practical applicability of graph-based metamaterial concepts in real-world wave systems.
