Nippon Antena Kabushiki Kaisha

Harada Industry Co., Ltd.

Jinichi Inoue

Masashi Wakui

Nobuo Arayama

Motoki Ohshima

Good electric characteristics are obtained even after an antenna being further incorporated into an antenna apparatus including an antenna case having a limited space. An antenna deviceis formed on an antenna substrateinstalled upright in an antenna base. A flat antenna unitis fastened to the antenna baseso that the flat antenna unitis immediately below the antenna device. If the wavelength of a center frequency in an operating frequency band of the flat antenna unitis &#x3bb;, an interval between an upper surface of the flat antenna unitand a lower end of the antenna deviceis set to about 0.25 &#x3bb; or more. Accordingly, it becomes possible to make directional characteristics of radiation in a horizontal plane of the flat antenna unitnon-directive without being affected by the antenna deviceand also to achieve good gain characteristics.

Antenna apparatus

An object of the present invention is a small composite antenna that is capable of operating in a plurality of different frequency bands. A first antennaconstituting a GPS circularly polarized loop antenna is formed on a dielectric substrate. A second antennaconstituting an ETC square patch antenna is formed on substantially the same axis as the first antenna. An earth pattern is formed in the underside of the dielectric substrate, and a recess in whose bottom face an earth pattern is formed so as to lie opposite the second antennais provided. An arc-shaped feed patternis electromagnetically coupled to the first antennaso as to supply electricity thereto, whereby this antenna is made to operate as a right-handed circularly polarized antenna. Electricity is supplied by a coaxial cable to the second antennato cause same to operate as a right-handed circularly polarized antenna.

Composite antenna

An object of the present invention is to provide a small composite antenna that is capable of operating in a plurality of different frequency bands. A GPS first loop antennais formed on a dielectric substrate. A VICS radio wave beacon second loop antennais formed on substantially the same axis within the first loop antenna. In addition, an ETC patch antennais formed in the bottom face of a recessprovided substantially in the center of the dielectric substrate. An earth pattern is formed over the whole of the underside of the dielectric substrate. An arc-shaped first feed pattern is electromagnetically coupled to the first loop antennaso as to supply electricity thereto and cause same to operate as a right-handed circularly polarized antenna. An arc-shaped second feed pattern is electromagnetically coupled to the second loop antennaso as to supply electricity thereto. Electricity is supplied by a coaxial cable to the patch antennato cause same to operate as a right-handed circularly polarized antenna.

A first dipole antenna consisting of dipole antennae and a second dipole antenna consisting of dipole antennae are disposed so as to be approximately orthogonal at approximately &lgr;/4 intervals on a reflecting plate having a diameter of approximately &lgr;/2 or more. By disposing a plurality of non-feeding elements to around the first dipole antenna and second dipole antenna and isolating them by approximately &lgr;/4, the transmission gain and axial ratio in a low elevation angle can be improved.

Growing community of inventors

Warabi, Japan

Jinichi Inoue