Resonance splitting in two coupled circular closed-loop arrays and investigation of analogy to traveling-wave optical resonators

Abstract

A well known property of large circular closed-loop arrays is that when the dimensions and the distance of the cylindrical dipoles are properly chosen, the arrays possess very narrow resonances. As far as single isolated loop arrays are concerned, the phenomenon has been predicted and analyzed in the past in the framework of *two-term" theory. In the present paper the same methodology is, for the first time, applied to investigate the system of two coupled identical circular arrays. It is found that the spectral profile of this new array is characterized by the coupling-induced splitting of the resonances of the single loop array into symmetric and antisymmetric supermodes, in direct analogy with other types of coupled electromagnetic cavities. Due to the circular symmetry of the individual arrays, the phenomenon is strongly correlated to the optical counterpart of two coupled traveling-wave optical resonators, such as whispering gallery or microring resonators. By borrowing the resonance splitting model from optical resonators, this analogy connection is investigated and interesting conclusions are reached.