Tuning the Operating Band of an Artificial Magnetic Conductor

Abstract

Approximate formulas for calculating the coefficient of reflection from an artificial magnetic conductor (AMC) based on a capacitive lattice (with additional capacitances installed between its elements to tune the AMC operating band) were derived. The results of numerical calculations validating the estimates using approximate formulas are presented. The engineering feasibility of a thin radio absorber with a tunable operating band based on this AMC and a resistive film was demonstrated theoretically and experimentally. The results of measurements performed in a waveguide with a cross section of 72 × 34 mm² revealed that the center frequency of the operating band of the radio absorber shifted from 4.9 to 2.7 GHz as additional capacitances varied from 0 to 1.27 cm.