Abstract: Rear and forward reflector shells or dishes (36,38) are independently supported on a dynamically rigid truss structure (12) by means of separate studs extending from the forward nodes of the truss to the two shells. Forward node (22) carries adjustable rear shell stud (52) and independently carries adjustable forward shell stud (80). Both of the studs have flat portions oriented normal to the radius of the shell so that radial shell expansion due to temperature and temperature differential minimize shell distortion.

Abstract: A method of fabricating hollow square inner conductors having precise outer dimensions is disclosed. A first "u" shaped slot (10) is machined in a base plate (12) and a cover plate (16) is then brazed to the sloted surface (18). The cover plate (16) is machined to provide a first wall (20) of desired thickness. Second and third slots (22, 24) are machined in the base plate (12) parallel to the first slot (10) on opposite sides thereof to provide second and third walls (26, 28) of the hollow conductor (38). A sacrificial metal (30) having a melting point below that of the base plate metal is cast into the second and third slots (22, 24). A fourth wall (36) is formed by machining material from the base plate face (32) opposite the slotted surface (18). The sacrificial metal (30) is then removed to provide the hollow inner conductor (38) having precise outer dimensions (A, B).

Abstract: A frequency selective surface having a fibrous ceramic material body and a metallic grid on a reflecting face thereof. The body is formed by bonding a mass of silicon dioxide fibers together at their intersection points, as with a fusing agent such as boron nitride in a sintering process, resulting in an array of fibers with cellular porosity intentionally distributed through the body to reduce its density. Other types of ceramic fibers can be used either alone or in combination with the silicon dioxide fibers. The grid is attached to the reflecting surface or deposited thereon. The frequency selective surface finds particular utility in satellite microwave communications satellites.

Abstract: An antenna reflector having a parabolically curved reflecting surface is formed of a cellular ceramic material having ceramic fibers fused together in a rigid cellular structure. The body is formed by bonding or fusing a mass of silicon dioxide fibers together at their points of intersection with a fusing agent such as boron nitride in a sintering process, resulting in a fused array of fibers with cellular porosity intentionally distributed through the body to reduce its density. Other types of ceramic fibers can be used either alone or in combination with the silicon dioxide fibers. The antenna reflector finds particular utility in parabolic antennas for satellite microwave communications systems.