Circularly polarised mechanically steerable reflectarray

In the paper a spatial phase shifter, circularly polarised reflectarray is presented. The reflectarray uses peripherally short circuited circular discs. Each element is excited at its fundamental, TM/sub 11/, mode, and, by their mechanical rotation, phase shifting of the incident circularly polarised wave, with the same hand of polarisation as the incident wave front, occurs upon re-reflection. Theoretical and experimental results for the reflected signal phase of such elements are presented. It is shown that the phase of the reflected signal is twice the angle through which the disc is rotated. Far-field results illustrating beam steering for a 5/spl times/5 array of such elements are also presented.