Abstract: A low-noise-block downconverter (LNB) for use with flat antennas receiving dual polarized electromagnetic waves includes a body case mounted to a rear side surface of the flat antenna, the body case having two wave guide input ports corresponding to wave guide apertures of the antenna and enclosing a selective device alternatively allowing either one of two outputs corresponding to two different type polarized electromagnetic waves received.

Abstract: A converter for use with planar antennas has a probe projected into an input part of waveguide structure as extended along a plane including a circuit board in a body of the converter, an opening of which input part being disposed in parallel to the plane, whereby the converter input part is allowed to have a thickness limited within the thickness of the converter body to remarkably reduce the entire thickness for effectively realizing a minimization in the thickness of the converter.

Abstract: A plane antenna comprises a power-supply circuit, a radiator circuit and an earthing conductor which are stacked respectively with a dielectric layer interposed between them, in which the power-supply and radiator circuits are made independent of each other as electromagnetically coupled to each other and at least one of the dielectric layers is formed with a foamed resin, whereby insertion loss can be reduced to remarkably improve the antenna characteristics. Only with the interposition of the foamed resin dielectric layer or layers, an effective separation is achieved between at least the power-supply circuit and the earthing conductor or the power-supply circuit and the radiator circuit, for a large extent improvement in the assembling ability.

Abstract: A microwave plane antenna comprising antenna body including a plurality of conductive microstrip lines covered with a plastic film and a polyolefin series dielectric layer provided along the microstrip lines for lowering SHF band transmission loss while elevating reception gain. The antenna is enclosed in a plastic cover which includes portions constructed to permit the passage of microwaves while imparting appreciable strength to the cover.