Hitachi-kokusai Electric Inc.

Kokusai Electric Co., Ltd.

Kokusai Denki Kabushiki Kaisha

Other

Kanemi Sasaki

Mitsuru Muramoto

Mikio Takano

Hiroyuki Yasuda

Hirotaka Saito

Naoki Onishi

Sadao Ogawa

Shinya Kobayashi

Yoichi Okubo

Hiroyuki Murakami

Koji Moriya

Kiyohiko Itoh

Yuji Aoyagi

Satoru Ujiie

Manabu Yamamoto

Shinya Koboyashi

Kennzo Urabe

A radio communication apparatus includes a radio transmitting/receiving unit having a directional antenna and a storage unit storing reference image data and captured image data obtained by an imaging unit. The imaging unit has an optical axis oriented in the same direction as the radio wave direction of the directional antenna and captures an image related to a line of sight of the other opposed radio communication apparatus. The radio communication apparatus further includes an image processing unit comparing the reference image data with the captured image data and a control unit detecting, from the comparison result, and informing that an obstacle is traveling toward the aforementioned radio wave direction.

Radio communication apparatus, radio communication method, and radio communication system

There is disclosed a method of aligning an azimuth of an antenna by use of an antenna azimuth aligning instrument capable of economically and precisely aligning the azimuth in a case where a direction of a main beam of a directional antenna is matched with a counter antenna. There is provided a method of aligning the azimuth of the directional antenna by use of the antenna azimuth aligning instrument to be attached to the antenna for use in radio communication, the azimuth aligning instrument includes an aiming hole whose central axis is constituted in parallel with a main beam azimuth of the antenna and in which a diameter of an openingC on an operator's viewing side is set to be larger than that of an openingB on a target side, and the azimuth of the antenna is aligned using the centers of the two openings of the aiming hole as aims for a target.

Method of aligning antenna azimuth

A wireless system for use in a low power data communications in a sub-millimeter wave zone includes at least one wireless communications device including a directional antenna whose cross-polarization discrimination is not less than 24 dB, wherein the wireless system uses a plurality of planes of polarization selectively. The planes of polarization to be used are selected such that the number of non-occupied channels is largest by detecting the number of non-occupied channels depending on planes of polarization. The directional antenna, having a box shape whose front view is a right square, is formed as a single body with the wireless communications device, and the wireless communications device is fixed to a pole in a way that each side of the right square is slanted at 45&#xb0; with respect to the pole.

Wireless communications device

The present invention is to provide a radio system that enables effective reuse of a limited number of frequencies without the occurrence of interference between subscriber stations. In the radio system according to the present invention, each base station is divided into two or more sectors, each of which is provided with an antenna different in directivity on a horizontal plane. The antennas are so placed that the antenna beams cover all the directions on the horizontal plane as a whole, and all the antennas using the same frequency and polarized wave are so arranged to face in about the same direction.

Radio system

The cell expansion system and method maximize the use of communication signal resource such as frequencies and polarized waves in expanding base stations for wireless communication. The cell are divided into four equal sectors, and at least a pair of adjacent sectors of the adjacent cells shares a common signal for wirelessly communicating with each other.

Wireless communication system and method of maximizing the use of communication signal resource

Radio communication systems, e.g. cellular telephones, have employed a space diversity antenna system which includes a plurality of antennas. In the space diversity antenna system for use in the cellular telephone, since two antennas are positioned adjoining each other, the space diversity effect cannot be adequately provided. To solve this problem, the polarization diversity antenna system according to this invention incorporates a first antenna, a second antenna, and a conductive board on which the second antenna is fixed at a given position, thus preventing the current flowing in the conductive board from causing the reception characteristic of the second antenna to deteriorate.

Polarization diversity antenna system for cellular telephone

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

An intermediate frequency filter for an intermediate frequency used in the receiver section of a digital radio communications apparatus is composed of an amplitude-flat ceramic filter incorporating two ceramic resonators, a buffer means and a single tuning circuit having the center frequency thereof within the bandwidth of the amplitude-flat ceramic filter, all being connected in series with each other. The center frequency of the single tuning circuit and Q are adjusted to approximate the amplitude characteristic of the intermediate frequency filter to that of TBT filter (0.4.ltoreq.parameter m.ltoreq.1.0).

Intermediate frequency filter having a ceramic filter

A CM type directional coupler comprises a body having a dielectric layer, an annular magnet buried in the dielectric layer, a pair of transmission lines juxtaposed with a predetermined spacing between them in a magnetic area enclosed by the magnetic ring in the dielectric layer, and lead terminals extending from opposite ends of each of the transmission lines to outside of the dielectric layer, and all these elements are formed integrally with each other to provide a single device. Therefore, a large coupling factor and directivity are ensured, and the coupler can be designed very compact. This directional coupler can be manufactured with a highly improved yield and mass-producibility, so it is very suitably usable as a power detector in a portable telephone.

CM type directional coupler

A band-stop filter comprises a plurality of resonator units each comprised of an end-shorted coaxial resonator and a variable condenser connected in series therewith, a printed circuit board combining said resonator units in a multistage having thru-holes adjacent a bushing which isolates the inner conductor of the end-shorted coaxial resonator from the printed circuit board. A thru-hole conductor is provided in the thru-hole, and an adjusting screw having a radius is a little larger than the thru-hole. The adjusting screw can have both the proper torque and the electrical connection. The inner conductor surface of the resonator operates electrically as a stator and the adjusting screw operates as a rotor.

Band-stop filter

A branching filter for separating or combining two different frequencies without interference in radio communication equipment etc. One or both of two filter blocks for separating or combining two signal waves whose central frequency differ from each other are constructed from a dielectric bandpass filter which allows the desired wave of a block to pass and a SAW band stop filter being connected in series with said filter which allows the desired wave of a block to pass and stops passing of the desired wave of another block.

Branching filter

This invention relates to a di-electric bandpass filter using a di-electric resonator for selecting a desired wave and removing an undesired wave. The di-electric resonator has one central conductive hole (10) for resonance and more than one non-metallized coupling bores (2, 2) which are provided at the open faces of plurality of resonators (1, 1, . . . 1) which are disposed so as to contact the respective earth faces of each other. Neighboring coupling bores (2, 2) are connected by coupling metal pieces (4), whith output and input matching pins (3) inserted into either coupling bores or central holes. In this invention, it is possible to dipose the resonators freely as constructed in a bandpass filter using the space effectively so that a compact installation can be realized.

Growing community of inventors

Tokyo, Japan

Kanemi Sasaki