Abstract: A switch includes at least two distributed constant lines (2a, 2b) disposed close to each other, a movable element (11) arranged above the distributed constant lines so as to oppose these distributed constant lines and connecting the distributed constant lines to each other in a high-frequency manner upon contacting the distributed constant lines, and a driving means (13) for displacing the movable element by an electrostatic force to bring the movable element into contact with the distributed constant lines. The movable element has a projection (52a, 52b) formed by notching at least one end of an edge of the movable element which is located on at least one distributed constant line side. In this projection, a width (a) serving as a length in a direction parallel to the widthwise direction of the distributed constant lines is smaller than a width (W) of each of the distributed constant lines.

Abstract: A phased array antenna apparatus includes a plurality of radiation elements, a power supply unit, a power distributor, a feed probe, a plurality of electromagnetic coupling units, and a plurality of phase shifters. The radiation elements are aligned and arranged to be electromagnetically driven. The power supply units supply power to the radiation elements. The power distributor has a pair of conductive plates arranged to be parallel to each other and acts as a radial waveguide distributing the power supplied from the power supply unit to the radiation elements. The feed probe is arranged on one of the conductive plates to radiate an electromagnetic wave into the radial waveguide in accordance with the power supplied from the power supply unit. The electromagnetic coupling units are arranged on the other conductive plate in correspondence with the radiation elements to extract the electromagnetic wave radiated from the feed probe and propagating through the radial waveguide by electromagnetic coupling.

Abstract: An antenna system is adapted to be installed on a ceiling surface or on one of side wall surfaces of a space defined by the ceiling surface, the side wall surfaces and a floor surface. The antenna includes a reflector and a radiator element. The reflector has a grounded plate, a dielectric layer formed on the grounded plate, and metal strips having patterns parallel to the longitudinal direction of the space and formed on the dielectric layer. The radiator element is disposed to be perpendicular to a reflecting surface of the reflector. The radiator element may be in a bar form, a cylindrical form or at least partly a coil form. The distance between the center of the longitudinal direction of the radiator element and the reflector is set to be about 0.1 to 0.6 times the wavelength of the working frequency. The antenna system has high directivity along an elongate space such as a tunnel, a corridor or an underground shopping area.