Antenna system including a paraboloidal reflector and an exciter

Abstract

An improved antenna system of the type including a parabolic antenna with offset exciting in which only the upper portion of the parabola is used, an approximately horizontal bottom plate, and an exciter which is disposed above the bottom plate. The exciter has a tilt angle of about 50.degree.. The paraboloidal reflector is covered by a dielectric cover plate which is inclined to the vertical so that the cover plate and parabola contact in a single plane, and a portion of both sides of the width of the parabola is removed, and side sheets are provided to connect the paraboloidal bowl and the cover plate. The exciter is a conical multimode exciter with an aperture angle of about 100.degree. and is provided with at least one and preferably a plurality of concentrically arranged slits on the conical surface of the exciter facing the paraboloidal reflector with the depth of the slits decreasing in a direction toward the edge of the cone adjacent the reflector. The width of the slits is between .lambda./10 and .lambda./20, the spacing between adjacent ones of the slits is between .lambda./8 and .lambda./4, the smaller diameter of the conical exciter is about .lambda./1.2, and the larger diameter of the conical exciter is about 3.lambda., where .lambda. is the wavelength of the center frequency of the operating frequency band of the antenna system.

Dependencies are inferred from the claim text.