A light-weight, temperature-resistant spherical antenna lens is formed of an homogeneous ceramic material to provide a uniformly-distributed dielectric constant. The ceramic material formulation can be varied to adjust the dielectric constant for various wavelengths. A protective sealing coating is applied to the exterior surface and, because of the very high porosity of the lens, the sealant is applied over an under coating having essentially the same dielectric and temperature characteristics as the lens matrix material. The shaped spherical body of the lens is provided by press-forming and fusing together a quantity of highly-porous ceramic granules each being the same in composition and each having essentially the same pore size. Pore size is controlled by first preparing a ceramic slip, mixing the slip with an organic 'burn-out' material, such as stearic acid powder, and then subjecting the mix to a wet granulation process to provide granules of a particular size. A burn-out produces granules having the desired pore size which then are mixed with a mechanical binder, pressed to form the sphere and subsequently sintered to provide a rigid spherical structure capable of being machined and coated with the sealant glaze.
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