Parametric Representation of Ground Antennas for Communication Systems Studies

Mathematical models relating five important variables encountered in the consideration of ground antennas for communication systems are developed for both exposed and radome-sheltered structures. The variables are: diameter, cost, gain, frequency, and rms surface tolerance. Often, in communication systems studies, the costs associated * A preliminary version, "Trade-off Models for Ground Antennas in Microwave and Millimeter Wave Communication Systems," was presented at the Fifth Space Congress, Cocoa Beach, Florida, March 1968. 2145 2146 T H E BELL SYSTEM TECHNICAL J O U R N A L , DECEMBER 1968 with a ground antenna are estimated by using a simple relationship based on antenna diameter alone. The results of our study have a similar utility, but are substantially broader in scope and have greater flexibility. They represent some of the major features of ground antennas for use in the preliminary phases of communication systems planning. In spite of the refinements offered by the present models in comparison with previously available guidelines, parameters which are important in the design and operation of a specific ground antenna system are not included. For example, there is no provision for including antenna noise temperature. Hence, the comparison of concepts on the basis of signal-to-noise ratio is not possible. Similarly, the effect of aperture illumination and the side lobe levels to be expected are not considered. There are other factors which must be accounted for in the design process but do not appear in the present formuation.