Luneberg Reflectors Operating in Circular Polarization

The polarizers of radars operating in circular polarization are built in such a way that this type of radar cannot be tested with traditional Luneberg reflectors. We describe here a new class of Luneberg reflectors equipped with a special reflecting structure made up of a grating of metal wires and a metallized dome which enables to reverse the rotation direction of the reflected wave\´ s polarization and thus realize a passive responder which operates in circular polarization. The results are given for reflectors of 7" in diametre operating in Ku Band: radar cross section measured in circular polarization is more than 8 m2 in a 120° angle of response and a bandwidth of several GHz.