Hemispherically Scanned Antennas.

The report contains the results of a study of techniques for obtaining extended coverage element patterns for use on hemispherically scanned phased arrays on cylinders of large radius of curvature. It contains experimental patterns of slot radiators on such a cylinder covered with surface wave structures. Experimental patterns of slots coupled to parasitic dipoles extended around the cylinder are also included. An analysis that treats sources on reactive cylinders is performed to determine what type of surfaces will give extended coverage when the polarization is parallel to the cylinder axis. The results of the study indicate that improved coverage can be obtained using reactive surfaces that are selected to affect TE waves and TM waves in different manners. Such surfaces can be constructed by combining corrugated conductors and dielectric slabs. The combination can be selected to provide effectively the proper surface reactance to allow radiation near the horizon for both polarizations.
See also report dated Dec 73, AD-779 695.