Abstract: A waveguide structure carrying microwaves with two mutually orthogonal planes of polarization and in two different frequency bands, transmitted and received by an associated antenna, comprises two orthomode transducers in the form of coaxial cylindrical guide members of different inner diameters, the smaller-diameter transducer terminating in a short-circuiting end wall while the larger-diameter transducer, adjoining same at an annular shoulder, extends to a feed horn confronting a reflector. Each transducer is formed with two elongate peripheral access slots, opening onto respective rectangular-section branches, which are longitudinally bisected by mutually perpendicular axial planes while being relatively offset in axial direction.

Abstract: An antenna designed to emit a beam of generally elliptical cross-section has a reflector with a parabolic-elliptical concave surface conforming to the formula(x/p)+(y/q)=2zwhere p and q are the parameters of its parabolic cross-section in the xz and yz planes, respectively. A microwave feed located on a line interconnecting the foci of these two parabolas, preferably at the outer focus separated from the surface vertex by a distance q/2, generates a beam parallel to the axis whose ellipticity depends on the ratio q/p.