Near-field electromagnetic coupling between helices

Abstract

A fresh approach to the design of metamaterials formed from closely spaced helices is developed based on the retrieved values of electric and magnetic coupling coefficients between adjacent helices. A coupling retrieval method has been implemented to obtain numerical and experimental values for both electric- and magnetic-coupling coefficients between helical elements. Couplings between both right- and left-handed helices in side-by-side and axial arrangements are evaluated providing both positive and negative electric-, as well as magnetic-coupling components. The dependence of coupling strength on separation distance, relative axial rotation, helical pitch and the geometrical arrangement of the helices has been quantified both numerically and experimentally and a geometry giving zero net-coupling between very close helices is illustrated.