Resonant microwave fields and negative magnetic response, induced by displacement currents in dielectric rings: theory and the first experiments

Abstract

The theoretical basis and experimental verification of resonant phenomena in the electromagnetic fields generated by displacement current in the near zone of dielectric ring is presented. According to the traditional viewpoint, the dielectric has an influence on the electric field inside resonator. To the contrary, we demonstrate that the dielectric ring exhibits magnetic properties at resonance. The sliding incidence of plane microwave on this weakly absorbing ring is shown to provide the sharp and deep resonance in the components of generated field; this low loss circuit is operating as a resonant dielectric magnetic dipole. Splitting and broadening of resonance in the pair of these dipoles dependent upon their mutual arrangement is recorded. The phase shift equal to π between the magnetic components of incident and generated wave indicating the formation of negative magnetic response is demonstrated. Perspectives of using of this simple sub wavelength resonant magnetic dipoles in the all-dielectric circuitry are discussed.

Colossal magnetic fields in high refractive index materials at microwave frequencies

“…Metal-coated, aperture-type NSOM tips are particularly sensitive to the magnetic fields and have indeed been used to measure hotspots in the near magnetic field of silicon dimers at visible wavelengths 28 . In the case of GHz waves, the millimeter—centimeter scale structures with high dielectric constant allows measuring the spectrum of scattering using a local magnetic field sensor 54 – 56 . In our case, this sensor takes the form of a small metallic loop, which can efficiently measure the magnetic field component parallel to its axis (i.e., perpendicular to the loop plane).…”

Резонансное Рассеяние Плоских Электромагнитных Волн ГГЦ Диапазона Кольцевыми Диэлектрическими Линейными Структурами

“…Это необычное явление было продемонстрировано резонансным возбуждением магнитных мод и образованием отрицательной магнитной индуктивности в полностью диэлектрических субволновых кольцах в поле монохроматической электромагнитной волны [9,10]. Диэлектрические резонаторы можно рассматривать как обобщения известного колебательного контура Томсона [11], объединяющего индуктивные и емкостные свойства в одной резонансной структуре.…”

“…Ранее мы исследовали резонансные свойства тонкого диэлектрического кольца и эллипса [10,21,22], и было показано, что в случае падающей плоской электромагнитной волны наибольший резонансный отклик наблюдается на основных частотах магнитных мод, соответствующих дипольным резонансам. В случае скользящего падения плоской электромагнитной волны на диэлектрический контур основная резонансная магнитная мода характеризуется отрицательным магнитным откликом [10]. Показано, что такое кольцо действует как резонансный круговой магнитный диполь в GHz диапазоне частот.…”

Resonant phenomena in an all-dielectric rectangular circuit induced by a plane microwave

“…Although dielectric ring resonators supporting the concentric GHz modes were considered several decades ago [2], the systematic research of magnetic modes became a 'hot' topic later due to the discovery of 'artificial magnetism' [3,4]. This unusual phenomenon was demonstrated by resonant excitation of magnetic modes and the formation of negative magnetic inductance in all-dielectric sub wavelength rings in a field of monochromatic electromagnetic waves [5,6]. This topic is also related to the antieikonal limit, as presented in [7].…”

“…Previously, we investigated the resonant properties of a thin dielectric ring and an ellipse [6,10,34] and it was shown that in the case of an incident plane electromagnetic wave, the greatest resonant response is observed at the main frequencies of the magnetic modes corresponding to dipole resonances. In the case of a sliding incidence of the plane electromagnetic wave, the main resonant magnetic mode was characterized by a negative magnetic response [6]. Such a ring was shown to operate as a resonant circular magnetic dipole in the GHz range of frequencies.…”