Transmitting Antenna with Cosecant-Shaped Vertical Pattern for the 12-GHz Television System

A broadcasting antenna has an optimum performance if a constant electric field distribution within the coverage area is obtained. A constant field strength requires a cosecant-shaped vertical and omnidirectional azimuthal pattern. For this purpose the German Federal Post Office has developed the so-called polygonreflector antenna, consisting of six specially shaped reflectors with horn feeds. Using this device the field strength at the edge of the coverage area is increased by 4.5 dB in comparison with a conventional antenna.