Some aspects of curved frequency selective surfaces

Frequency selective surfaces are usually formed from arrays of elements printed on dielectric substrates or sandwiched between dielectric layers. They can be modelled using Floquet modal techniques when they are periodic and plane and infinite or curved into a complete cylinder. Arbitrarily curved finite surfaces present greater problems because it becomes necessary to perform the computations for groups of elements or for individual elements in the array. One approach is to use a ray tracing method. Instead, this paper studies curved arrays formed from a finite number of dipoles or rings that are free standing, and illuminated by an incident plane wave or line source. The analysis is similar to the Pocklington equation method applied previously by Allam and Parker (1987) to finite planar dipole arrays. Examples of singly and doubly curved arrays are shown.