Controlling Microwaves in Non-Hermitian Metamaterials

Abstract

Dissipative coupling is realized in a metamaterial structure leading to level attraction. This is achieved via the cooperative radiation of resonators to a common transmission line, which also supports the coexistence of bound states in the continuum (BIC) and an antiresonance. By aligning the BIC and antiresonance frequencies both the amplitude and phase of microwave transmission can be controlled, leading to a steep transition (up to 110 dB) from complete extinction to nearly perfect transmission. This transition is accompanied by a π-phase jump indicative of slow light. By repurposing dissipation as a coupling mechanism, non-Hermitian metamaterials open avenues for microwave sensing, switching, and slow microwave realization.