Structure of an Artificial Magnetic Conductor with a High Angular Stability of Resonance Frequency

An artificial magnetic conductor based on a capacitive grating the period of which is greater than the distance between the grating and screen is considered. It is shown that the electromagnetic field in such a structure is identical to the field in a thin plane waveguide and the resonance frequencies are predominantly determined by the period and distance between the neighboring elements of the grating. The numerical calculation of the frequency dependence of the phase of the reflection coefficient is used to prove that the structure may serve as an artificial magnetic conductor with a relatively high angular stability of the resonance frequency (the resonance frequency is shifted by no more than 1.5% when the angle of incidence ranges from 0° to 60°). Experiments with waveguide models prove that the structure may serve as an artificial magnetic conductor and a resonant radio absorber.