Design of electromagnetic band gap media based on crank-like chiral structures

Abstract

A new EBG (Electromagnetic Band Gap) structure with chiral crank elements is presented and its effects on the electric field propagation along a microstrip line are analysed and compared with the effects produced by mushroom-type inclusions. Chiral crank inclusions are distributed along both sides of the strip and the corresponding results are compared with those obtained by other elements commonly used to create EBG media, mushroom-type structures. A single row of high chirality structures on both sides of a transmission line produces a band gap with a wider bandwidth than that obtained by the inclusion of other elements commonly used to create EBG media, such as mushroom-type structures. Unlike what happen with mushroomtype inclusions, more rows of chiral elements do not change significantly the central frequency and bandwidth of the band gap. The proposed structure works in X-Band (8.2-12.4 GHz) and it is easily adaptable to other frequencies by changing the size of the crank inclusions. Several samples have been made in FR-4 printed circuit board and a good agreement has been found between numerical analysis and experimental measurements.