Design of a 360° Scanning Circularly Symmetric Polygon Lens

This paper presents a 360° scanning circular microwave lens based on the Bootlace lens design concepts. However, instead of allocating the beam ports and receiving ports on two opposite sides of the lens, the polygon lens alternates the beam and receiving ports in an interleaving order on all sides and allows the use of circular symmetry to cover 360° scanning. In this paper, a new analytical approach is proposed which minimizes the phase errors for the “perfect” focal points of the lens to design the polygon lens. In order to evaluate the proposed method, an octagonal lens was designed and fabricated. Each facet of the lens feeds a four-element rectangular patch array. The results show a full 360° coverage in the band of interest. Comparisons between measurements and simulations show a good agreement.