Design of a 40 dBi planar bifocal lens for mechanical beam steering at Ka-band

Abstract

A new design of planar lenses for mechanical beam steering at Ka-band is presented, which enables achieving simultaneously wide scanning coverage (40 degrees) with high directivity (40 dBi) and low beam distortion (side lobe level below -15 dB and scan loss better than -2.4 dB). The steering mechanism based on in-plane lens translation/rotation has been demonstrated in a previous 30 dBi antenna prototype at 30 GHz. We showed that aberrations, caused by the in-plane lens translation, become more significant with the increase of the lens size. Hence, the presented 30 dBi lens solution cannot be simply scaled to achieve the aimed 40 dBi directivity (a common specification for satellite communications at Ka-Band). Using a PO/GO approach, implemented in CST Microwave Studio®, we prove that the proposed bifocal design outperforms conventional unifocal phase correction.