A Microwave Anapole Source Based on Electric Dipole Interactions Over a Low-Index Dielectric

Abstract

The pursuit of non-radiating sources and radiation-less motion for accelerated charged particles has captivated physicists for generations. Non-radiating sources represent intricate current charge configurations that do not emit radiation beyond their source domain. In this study, we investigate a single non-radiating source, comprising a low-index dielectric disk excited by a split ring resonator. Employing analytical and numerical methods, we demonstrate that this configuration supports an anapole state, exhibiting minimal or no radiation, effectively representing a non-radiating source. The radiation suppression is accomplished through the destructive interference of electric dipoles excited on the metallic and dielectric components of the proposed prototype. Transforming the design into a cost-effective device capable of suppressing radiation, we achieve impressive numerical and experimental agreement, affirming the formation of the anapole state using the lowest order multi-poles. Moreover, the devised anapole device is remarkably compact, constructed from a low-index dielectric, and employs readily available components. As a versatile platform, the proposed device can spearhead anapole research for diverse applications, including sensing, wireless charging, RFID tags, and other non-linear applications.