Mechanical beam scanning reflectarray

In this communication, we present an all mechanical reflectarray which uses only rotating circular disks immersed in a circularly polarized field in order to effect an repetitively scanned beam. Here, each disk in the array acts as a spatial phase shifter and is constructed from a peripherally short circuited circular patch antenna operated in TM/sub 11/ mode. The disks are arranged as an N/spl times/1 linear array and each disk is successively made to rotate at /spl Omega/,2/spl Omega/,...,N/spl Omega/. When illuminated with an incident circularly polarized wave this results in a progressive variation of spatially encoded phase across the array which enables the signal reflected from it to be automatically scanned from broadside without the need for any electronic components. The scan rate for the arrangement is determined by the speed of rotation of the slowest element /spl Omega/. Far field results illustrating beam steering for a 5/spl times/1 array of such elements spaced at 0.69/spl lambda/ shows that is possible to achieve up to 10/spl deg/ of beam scan from broadside.