POLAR DESIGN AND MEASUREMENT TECHNIQUES FOR ELECTROMAGNETIC BANDGAP STRUCTURES

The purpose of this paper is two fold: first we propose a design technique for electromagnetic bandgap structures based on polar curves and mapping functions. The key advantage of this concept is that it allows increased capacitance without increasing element dimensions or thickness making it possible to increase or decrease the surface impedance on a per cell unit basis. Secondly, we report on a repeatable measurement technique for characterising the bandgap properties of EBG structures using an air spaced microstrip line. The device constructed is simple, economical, robust and capable of quantifying the properties of a wide range of EBG materials. In addition, the measurement technique is particularly applicable to fabric based EBG materials where measurements are especially challenging.