Wide-angle microwave lens for line source applications

A new "time-delay" scanner consists of a constrained wide-angle two-dimensional microwave lens with a straight front face in which lens elements connect arbitrary points on the inner and outer contours. The lens can operate at very short pulse lengths and can scan more beamwidths than any previously known device of its type. A phase analysis shows that this design has very small coma aberrations and that the lens can generate fractional degree beams. Criteria developed for selecting optimum lens parameters are given. The radiation patterns of an experimental model in which the lens elements consist of coaxial cables show the expected wide-angle characteristics. In further tests incremental scanning was obtained through the use of phase shifters in the coaxial lens elements. The design of symmetrical three-dimensional lenses is briefly discussed. A table of lens contour parameters is given for an optimum lens design with scan angle <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">\alpha</tex> of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">30\deg</tex> .