Electronically controllable surface for polarization control

This paper describes a method by which an electronically controllable surface can under DC control be made to convert a circularly polarized, CP, incident signal to a linearly polarized, LP, signal, or, to a circularly polarised signal of the opposite hand with respect to the incident signal by virtue of reflection from the grid surface. The surface consists of a periodic 2D LC array of printed inductors and diodes backed by a solid metal ground plain spaced h/4 behind it. The grid is excited using a circularly polarised signal generated through a squeeze-spread polarizer I Potter horn arrangement. With the arrangement as presented better than 3dB axial ratio can be achieved over a 150MHz bandwidth for CP and better than l2dB axial ratio over the same bandwidth for LP.