Periodic Arrays of Magnetoelectrically Excited Double and Single Split-Ring Resonators as Artificial Magnetic Conductors

Abstract

The amplitude and phase of the reflection coefficient of periodic arrays of electrically conducting elements in the form of double and single split rings are determined for two orientations of these rings, corresponding to magnetic (H) and magnetoelectric (HE) excitation. It is shown that, in the case of the HE-excitation of the rings, the arrays possess the properties of an artificial magnetic conductor or a high-impedance surface. The electric and magnetic fields near the arrays are calculated, and the dependence of the impedance on the distance between the array and the plane in which the impedance is determined is obtained. It is shown that the maximum of the impedance is in close vicinity of the array and can amount to tens of thousands of ohms. The feasibility of implementing a modified Salisbury radio absorber of small thickness by means of such arrays is shown theoretically and experimentally. It is also shown that, under illumination of an array of limited dimensions by a closely placed dipole, the screening effect reaches –30 dB with good matching of the dipole to the feed line (the reflection coefficient in the line is less than –20 dB).