Abstract: It is possible to obtain a wide-band feeder circuit a lower conductive plate provided substantially in parallel to an upper conductive plate, a short-circuit portion provided in a concave manner at a central portion of the lower conductive plate, and a countersunk portion provided in a convex manner at a central portion of a short-circuit plate forming a bottom of the short-circuit portion. It is also possible to obtain an antenna including such a wide-band feeder circuit.

Abstract: Provided is an antenna capable of establishing electrical conductivity between a flange-like short-circuit section of a power supply section and a thin metal plate even in a harsh temperature environment in a space environment. Under a state in which an apical portion of a power supply section is inserted from an outer side of a face plate into a hole for the power supply section of a thin metal plate, a dielectric plate, and a metal plate, a plurality of screws are inserted from the outer side of a flange-like short-circuit section through a plurality of insertion holes of the flange-like short-circuit section, the thin metal plate, and the dielectric plate, and the plurality of screws are threadingly inserted into a plurality of tapped holes of the metal plate so that electrical conductivity between the flange-like short-circuit section and the thin metal plate is established through direct contact.

Abstract: It is possible to obtain a wide-band feeder circuit a lower conductive plate provided substantially in parallel to an upper conductive plate, a short-circuit portion provided in a concave manner at a central portion of the lower conductive plate, and a countersunk portion provided in a convex manner at a central portion of a short-circuit plate forming a bottom of the short-circuit portion. It is also possible to obtain an antenna including such a wide-band feeder circuit.

Abstract: A waveguide band-pass filter has at least two resonators each consisting of a high-impedance section and a low-impedance section. The resonators are cascade-connected at intervals of .lambda.g/4 in a waveguide.