This paper reports a novel approach using an inductive loading to reduce the resonant frequency of a mushroom-shaped high impedance surface. The current path is extended on the mushroom-shaped structure's vias and additional traces, which introduces a three-dimensional inductor to the unit cell and leads to an increase in total inductance. As a result, the resonant frequency of the high impedance structure decreases, and a smaller unit cell size can be achieved at the low gigahertz frequency range. Finite element electromagnetic simulation, equivalent circuits modeling, and experimental measurements suggest the feasibility of the proposed approach.
A high impedance surface has far-reaching potential in wireless applications, but realization of the surface operating at sub-GHz ranges is challenging due to its size limits in practical applications. Here, we present a novel inductive technique based on multi-turn square spiral loops. The introduction of the spiral loops to a mushroom-shaped high impedance surface provides additional current path, thereby results in a dramatic increase in its total inductance at given dimensions, and therefore leads to a significant reduction in a resonant frequency of a high impedance plane. Electromagnetic simulation results reveal that a resonant frequency shifts downward 1 GHz at a given dimension, and they are in good agreement with results from an analytical model for the proposed structure. Experimental measurements suggest the feasibility of the proposed approach.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.