Unit Cell Analysis of Cylindrical Conformal Connected Arrays

Abstract

We present an analysis of cylindrical connected array unit cells. Analytical expressions of the active input impedance are derived for both connected slots and dipoles in the presence of a backing reflector. The dipoles and slots can be oriented along the circumferential or longitudinal directions in cylindrical coordinates. A study on the variation of impedance as a function of the radius of curvature is presented. Difficulties with the numerical implementation of high-order cylindrical Floquet modes are discussed. To solve these issues, a method is proposed to approximate the higher-order mode component of the cylindrical array impedance with the one of the equivalent planar geometry. This approach is justified by the observation that the reactive energy associated with the unit cell is weakly dependent on the curvature.