Kokusai Electric Co., Ltd.

Other

Kabushiki Kaisha Toshiba

Tokyo Shibaura Denki Kabushiki Kaisha

Kiyohiko Itoh

Sadafumi Sakamoto

Katsumi Ushiyama

Kanemi Sasaki

Mitsuru Muramoto

Kazutaka Hidaka

Kensei Sugita

Giho Makino

Manabu Yamamoto

Yoshihiko Mikuni

A slot array antenna with a cavity of a simple construction having a plurality of slots formed on a dielectric substrate and capable of providing good directional characteristics while minimizing inter-slots coupling. The slot array antenna ( ) includes a power supply line in the form of a micro-strip line formed on one surface of the dielectric substrate, a slot antenna portion ( ) with a plurality of slots ( ) formed on the other surface of the dielectric substrate in an array-like fashion so as to extend perpendicularly to the micro-strip line with the dielectric substrate interposed therebetween, and a reflector ( ) with a cavity ( ) having an opening disposed in opposition to a plane on which the plurality of slots ( exist). In this case, if the cavity has a width narrow enough to cut off a frequency of radio waves to be used, the directionality of the slot array antenna can be optimized.

Slot array antenna with cavities

A small antenna for portable radios and the like in which two planar conductive boards are disposed in parallel relationship at a spaced interval which is small when compared with received radio wavelengths. A dielectric frame is disposed between the two planar conductive boards keeping them at the preselected spaced interval. Arbitrary feeding points are selected along the edges of the two conductive boards and at least one conductor is positioned at an arbitrary selected feeding point to short-circuit the two conductive boards. In some cases a plurality of arbitrary feeding points may be selected along the edges of the two conductive boards and a plurality of conductors positioned at the plurality of arbitary selected feeding points which short-circuits the conductive boards. The positions of the plurality of conductors which short-circuit the conductive boards may be automatically changed at will to provide the most desirable condition responsive to the direction of the radio waves.

Small antenna

A miniature antenna, in which a pair of square conductor plates disposed in parallel with a spacing sufficiently smaller than the wavelength used are fixed to each other to an insulating frame to form an antenna structure which is used also as a case. Feeding terminals are provided at a desired position on one side of each of the conductor plates. High-frequency-wise short-circuit elements are provided at a plurality of positions on other sides of the conductor plates. A gravity-direction sensor, which produces an output in accordance with the direction of gravity, is provided in the case. The plurality of short-circuit elements are selectively short-circuited by the output of the gravity-direction sensor so that the plane of polarization of the antenna is brought into agreement with the direction of gravity.

Miniature antenna

A portable radio receiver assembled in a case. In accordance with the present invention, the case is also employed as an antenna of the portable receiver. The case is composed of a pair of parallel-opposed square conductor plates interposed therebetween a space sufficiently smaller than the wavelengths of received waves of the portable radio receiver, a frame of insulating material interposed in the space. Feeding terminals of the portable radio receiver are provided at desired positions on one pair of opposed sides of the parallel-opposed square conductor plates. Each of short-circuit elements of high-frequency-wise is provided on other pair of opposed sides of the parallel-opposed square conductor plates so that the direction of the plane of polarization of the antenna can be changed by short-circuiting any one of the short-circuit elements. A control circuit is provided in the case for selectively short-circuiting one of the short-circuit elements to obtain a larger received output from the feeding terminals.

Portable radio receiver

A planar antenna includes a first slotted waveguide serving as a power-feed unit, and a second slotted waveguide of planar type coupled with the power-feed waveguide, for radiating circularly polarized microwaves into space. The second waveguide has a metal plate in which a two-dimensional slot array consisting of a plurality of rows of slots is formed. An insulative layer is provided on the second waveguide to cover the slot array. A plurality of rows of metal patch radiators are provided on the insulative layer. These patch radiators are electromagnetically coupled with the slots, respectively, in such a manner that each radiator is directly excited by the corresponding slot through the insulative layer, thereby radiating circularly polarized microwaves.

Planar antenna with patch radiators

A linear polarization strip antenna which comprises a dielectric substrate whose backside is fitted with a conductive ground film, a power supply strip line which is formed of a conductive film and on the surface of the dielectric substrate, and a linear polarization radiation element. The strip line and radiation element are electromagnetically coupled together. A diode is connected between a top end of the strip line and a ground terminal. The top end of the strip line is selectively set at an open or grounded state according to the conductive state of the diode to vary the mode of electromagnetic coupling between the strip line and radiation element, thereby changing the direction in which the radiated electromagnetic wave is polarized.

Growing community of inventors

Sapporo, Japan

Kiyohiko Itoh