Resonant Enhancement and Confinement of Microwave Field in Coupled Conductive Rod Systems

We investigated the resonant interaction of incident microwaves with a finite linear array of equidistantly arranged conductive rods of finite height. When strong coupling is established between adjacent rods, which act as open resonators for radial waves, a series of resonances emerges, corresponding to the number of rods in the array. Each resonance exhibits distinct charge oscillation amplitudes and phases along the rods, leading to varying radiative losses. Notably, in a system of two resonantly interacting rods, antiphase charge oscillations result in a nearly 30-fold increase in localized field intensity and a quality factor of approximately 400. This study demonstrates the feasibility of creating high-quality open resonators with sub-wavelength confinement, offering the potential for microwave-to-optical conversion and enabling control over quantum processes in materials, thereby broadening their application scope.