A novel asymptotic high frequency UTD ray solution is developed for predicting the collective radiation by a large finite conformal antenna phased array, or aperture, on a canonical perfectly-conducting circular cylindrical geometry. The conformal aperture can be formed by a large complex array recessed just below the cylindrical surface and covered by a flush mounted radome. The present approach is in contrast to the element by element array field summation approach, which is less efficient, and which also lacks physical insight into the array radiation mechanisms.
The distribution of the weights over the large number of conformal discrete array elements, or over the sampled elements into which a large conformal aperture source distribution is discretized, is represented very compactly by its DFT spectrum. Only a relatively few DFT terms, which remain significant, are retained. Each significant DFT component generates a handful of UTD rays which are launched from the array/aperture. These UTD rays consist of a geometrical optics type Floquet modal component from the interior of the array/aperture, as well as edge diffracted and corner diffracted Floquet modal constituents from a point on each of the edges, and from the corners of a finite conformal array/aperture boundary, respectively. Those edge and corner diffracted rays which graze the cylinder surface also propagate along geodesic paths on the cylinder, to shed along their forward tangents as surface diffracted rays.
The present canonical solution provides the basis for future extensions to deal with the collective radiation from large arrays/apertures on a doubly curved smooth convex surface. Numerical examples are presented to illustrate the utility of the present DFT-UTD method.
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