Interleaving sparse arrays: a new way to polarization-agile

Abstract

Application such as polarization diversity communications, frequency re-use and syntheti aperture radar (SAR) may benefit from the use of polarization-agile antennas, i.e. antennas whose polarization state can be dynamically changed over time (see [1] fir a comprehensive survey on this topic). Most polarization-agile antennas described [1] make use of doubly-polarized elementrary radiators in conjunction with active devices, such as PIN diodes, for varying the polarization properties of the radiated waves 9see[2] for a typical implemention of this conept).
The present contribution advocates and alternative approach to obtaining polarization-agility. The strategy relies on interleaving (complementary) sparse sub-arrays each of which radiates waves with linear, orthogonal polarizations. In this manner, any polarization state: adjustable linear, right- and left-handed circular or elleptical can be synthesized at array level. The advantage of the proposed appraoach is that it makes use of simple elementary antennas radiating linearly-polarized waves, thus avoiding the complicated doubly-polarized elements abd the need fir PIN diodes for controlling the obtained polarization.
The validity of this approach is demonstrated by analyzing two examples of inter-leaved array antennas that allow obtaining an arbitrarily rotated, linear polarization.