Ka-Band Wideband Large Depth-of-Field Beam Generation Through a Phase Shifting Surface Antenna

A wideband phase shifting surface (PSS) antenna is presented with stable and large quasi-nondiffraction range. The operation principles and design procedures for the wideband near-held focusing antenna with large depth-of-field are introduced. Then, the difference between the depth-of-field (Zmax)fixed and the half-power beamwidth-fixed wideband design is demonstrated. As an example, a wideband Zmax-fixed PSS antenna is designed and fabricated. Phase shifts of PSS elements are synthesized by using a least mean-square error minimization method to approximate the ideal phase shift on the aperture of the antenna within the entire bandwidth. The developed prototype can be used as a Zmax-fixed beam launcher from 26.5 to 30.5 GHz. This type of antenna can be easily fabricated with the standard Printed Circuit Board process and fed by a horn antenna with an arbitrary polarization. The proposed structure has unique advantages: wideband applicable, large depth-of-field, and variable polarizations.