Coupling coefficients and active element patterns of finite waveguide arrays

The paper presents an efficient approach for computing the element reflection coefficient and radiation patterns of large finite arrays, using the results from an infinite array analysis. First, assume that the active element pattern of the array, where only one element is excited and the rest are terminated, can be approximated by the product of the array factor and isolated element pattern. The array factor is formed by the excited element and the coupled neighbouring elements. Then the pattern of a finite array with N elements is also the product of the array factor, which contains the mutual coupling effects, and the isolated element pattern. We are concerned with obtaining the scattering parameters or coupling coefficients of a finite array and the validity of our active element pattern assumption. The isolated element pattern is calculated with the other elements removed and for an open-ended waveguide the pattern is well known.