A New Approach to Broadband Array Design using Tightly Coupled Elements

Abstract

A fundamentally different approach to broadband array design has been developed and validated with measured hardware. Traditional array design is based on designing an isolated element with the desired bandwidth and radiation characteristics and does not account for the mutual coupling that occurs when this element is placed in an array environment. It is well known that undesired mutual coupling in an array can cause dramatic changes in antenna element impedance and radiation patterns. Harris' new approach treats the array aperture as a periodic surface so that the performance of elements within the array environment is assured. The approach is similar to that used to design a frequency selective surface, another periodic, highly-coupled structure. The resultant array apertures are inherently low-profile in cross-section, amenable to conformal implementations, and are able to maintain efficient characteristics over large scan volumes with bandwidths approaching a decade. This paper will present an introduction to this design methodology supported by predicted and measured results from several array designs.