Loading artificial magnetic conductor and artificial magnetic conductor absorber with negative impedance convertor elements

The general properties of a frequency selective surface loaded with negative impedance converter (NIC)‐based active loads are discussed from a theoretical perspective. The stability problem associated with NIC circuits embedded in artificial magnetic conductor (AMC) and AMC absorber applications is studied using pole‐zero analysis. The requirements and constraints for achieving stable operation with enhanced bandwidth using negative capacitance as realized by a floating NIC network are derived. Furthermore, it is shown that it is nearly impossible to simultaneously implement a negative capacitor and a negative inductor to such structures.