A steerable beam antenna system operable to produce a steerable antenna beam having a plurality of selectable polarizations, the antenna system comprising: a feed line defining an axis X; a first array of switchable scatterers disposed along a first side of the feed line parallel to the axis X; and a second array of switchable scatterers disposed along an opposite second side of the feed line parallel to the axis X, wherein the second array of switchable scatterers is a mirror image of the first array of switchable scatterers relative to a mirror plane defined by the feed line; wherein the first array of scatterers is configured to scatter an electromagnetic wave propagating through the feed line so as to form a first steerable antenna beam portion with a first polarization, and the second array of scatterers is configured to scatter the electromagnetic wave propagating through the feed line so as to form a second steerable antenna beam portion with a second polarization orthogonal to the first polarization; wherein each of the scatterers (90 and 92) in the first and second arrays (82 and 84) is switchable between a high state and a low state, wherein the scatterers (90 and 92) in the high state and the scatterers (90 and 92) in the low-state in each of the first and second arrays (82 and 84) defines a pattern having a period P = nd, where n is the number of scatterers (90 and 92) between successive scatterers (90 and 92) in the high state and d is the separation distance between adjacent scatterers (90 and 92) that is no greater than one-third the wavelength λ of the propagating electromagnetic wave; and wherein the scatterers (90 and 92) in the first and second arrays (82 and 84) are switchable to shift the pattern of scatterers (90 and 92) in the high state and scatterers (90 and 92) in the low state in at least one of the first and second arrays (82 and 84) relative to the pattern of scatterers (90 and 92) in the high state and scatterers (90 and 92) in the low state in the other of the first and second arrays (82 and 84) by a selectable period shift ΔP that yields a steerable antenna beam having a selected polarization from the plurality of selectable polarizations. a feed line defining an axis X; a first array of switchable scatterers disposed along a first side of the feed line parallel to the axis X; and a second array of switchable scatterers disposed along an opposite second side of the feed line parallel to the axis X, wherein the second array of switchable scatterers is a mirror image of the first array of switchable scatterers relative to a mirror plane defined by the feed line; wherein the first array of scatterers is configured to scatter an electromagnetic wave propagating through the feed line so as to form a first steerable antenna beam portion with a first polarization, and the second array of scatterers is configured to scatter the electromagnetic wave propagating through the feed line so as to form a second steerable antenna beam portion with a second polarization orthogonal to the first polarization; wherein each of the scatterers (90 and 92) in the first and second arrays (82 and 84) is switchable between a high state and a low state, wherein the scatterers (90 and 92) in the high state and the scatterers (90 and 92) in the low-state in each of the first and second arrays (82 and 84) defines a pattern having a period P = nd, where n is the number of scatterers (90 and 92) between successive scatterers (90 and 92) in the high state and d is the separation distance between adjacent scatterers (90 and 92) that is no greater than one-third the wavelength λ of the propagating electromagnetic wave; and wherein the scatterers (90 and 92) in the first and second arrays (82 and 84) are switchable to shift the pattern of scatterers (90 and 92) in the high state and scatterers (90 and 92) in the low state in at least one of the first and second arrays (82 and 84) relative to the pattern of scatterers (90 and 92) in the high state and scatterers (90 and 92) in the low state in the other of the first and second arrays (82 and 84) by a selectable period shift ΔP that yields a steerable antenna beam having a selected polarization from the plurality of selectable polarizations.