Hitachi, Ltd.

Hiroshi Kondoh

Hiroshi Shinoda

Toshiyuki Nagasaku

Hideyuki Nagaishi

Shiho Izumi

Kenji Sekine

Naoyuki Kurita

Terumi Nakazawa

Mikito Tsubota

Hiroshi Kuroda

Ken Takei

Satoru Kuragaki

Kazuhiko Sato

Hideaki Sasaki

Kazuaki Takano

Toshio Miyamoto

Yuzo Taniguchi

Tomio Yamada

Mitsuhide Sasaki

Eiichi Hase

Michio Tanimoto

Kazuo Matsuura

Tooru Fujioka

Kenichi Mitzuishi

Kazuhiro Nagaoka

Keigo Kamozaki

Isao Arai

Kazumichi Sakamoto

In a sensor and a radar for measuring the distance and the moving speed of a target by radiating a radio frequency, particularly a millimeter wave, compatibility between cost reduction and high detection performance has been conventionally a significant problem. In the present invention, the frequency of a transmitted signal changes during a fixed time while performing digitally-frequency-modulation on frequency sweeping straight lines extending, with different slopes relative to the time axis, from plural slightly different initial values serving as starting points, the signal is transmitted after being modulated so as to periodically repeat the sweep time serving as a unit, signal components corresponding to the respective sweeping slopes are digitally sampled, in synchronization with the transmitted modulation signal, from a received signal which is reflected and returned from a target, and the received signal is analyzed.

Radar, radio frequency sensor, and radar detection method

There is provided a highly accurate velocity sensor having a reduced detection error. A sensor circuit unit generates an electromagnetic wave and emits it from a transmission antenna. Furthermore, a reception antenna receives a reflection wave from the ground and a mixer mixes it with a local signal, thereby generating a low-frequency signal. The electromagnetic wave emitted from the sensor circuit unit shapes a beam by a dielectric lens before emitting it toward the ground. Here, the beam shape is such that the beam width in the vicinity of the sensor is smaller than the beam width in the vicinity of the ground.

Velocity sensor and ground vehicle velocity sensor using the same

An automotive radar having a high level of azimuth accuracy and a broad detectable range by virtue of preventing leaks of unnecessary waves to receiving antennas is to be provided. A transmitting array antennaand receiving array antennasare arranged on an antenna plate (grounding conductor plate)which serves to ground the antennas, and radio wave absorbersare arranged on two sides of the edgesof the antenna plate. The radio wave absorbersmay be configured of, for instance, a sponge material containing radio wave absorbing grains.

Automotive radar

A high frequency circuit module for use in an automotive radar or the like, in which RF circuit parts are mounted on both sides of a hard multilayer dielectric substrate, and a transmission line connecting the RF circuit parts provided on both sides is constructed by a via group including a periodical structure or a via having a coaxial structure perpendicular to faces of the multilayer dielectric substrate. As the multilayer dielectric substrate, a hard multilayer substrate using metallic layers as a microstrip line wiring layer, a DC/IF signal line layer, and grounding metal layers for shielding which are disposed on and under the DC/IF signal line is employed. By using the transmission line achieved by a through via having the periodical structure or the through via having the coaxial structure, an electromagnetic wave propagating in parallel between the grounding conductors is confined.

High frequency circuit module

The invention intends to provide a sensor module suitable for miniaturization and reduction in costs, in the radar sensor that uses a millimeter or sub-millimeter wave signal of which frequency is more than 20 GHz. To accomplish this problem, the radar sensor is integrated into a one chip MMIC, in which an active circuit including an oscillator and a mixer is formed with an antenna on one semiconductor substrate. Further, the MMIC is sealed with a resin package. A dielectric lens is formed on the resin package over the antenna to attain a desired beamwidth. Thereby, the lens and the resin package can integrally be formed by a metal mold, thus reducing the cost.

Radar sensor

An automotive radar which can process signals at high speed to detect a target in a wide angle range is provided. The automotive radar comprises a transmitting antenna which emits an electromagnetic wave, two receiving antennas which receive the electromagnetic wave reflected by a target, an antenna plate on which the transmitting antenna and two receiving antennas are arranged. It also includes a drive which rotates the antenna plate in an azimuth direction, which corresponds to the direction of arrangement of the two receiving antennas, to scan a detection angle formed by the two receiving antennas. The drive has rest time between scans to stop rotation. The automotive radar also includes a signal processor which detects the azimuth angle of the target with respect to a reference direction during the rest time according to received signals from the two receiving antennas and the rotation angle of the antenna plate at rest.

There is provided a device in which surroundings of a building can be monitored using a sensor; when detecting an intruder, an object can be detected even in the case of bad weather; and a predetermined area can be monitored using as few sensors as possible. The device includes a security system which emits a radio wave from a building to a predetermined area outside the building to detect an object, and on the basis of output of the object detecting unit, a judgment is made as to whether or not the object will intrude into the predetermined area.

Security system

The oscillator includes an active device, a substrate, a microstrip line formed on the substrate, and a dielectric block. The resonator is made up with the microstrip line and the dielectric block that is disposed so as to couple with the microstrip line. The active device produces a negative resistance in a desired oscillation frequency band. The dielectric block is set such that a resonance frequency of the lowest order mode of the dielectric block is lower than a desired oscillation frequency, and the resonance frequency of one of the higher order modes coincides with the desired oscillation frequency. The oscillator is generated with the higher order mode of the resonator. Thus, the invention provides at a low cost a millimeter wave band oscillator of a low phase noise by using this oscillator, and a transmitter-receiver module and a radar system applying this oscillator to the local signal generator.

Oscillator, transmitter/receiver module and radar system

A high frequency communication device which can reduce undesired electromagnetic coupling inside and outside a box thereof in which circuit parts constituting a transmitter-receiver circuit are contained. Periodic structures () are provided on at least a part of a wall constituting a box () so that the periodic structures () serve as a filter which has a non-propagating frequency band corresponding a frequency band covering an undesired electromagnetic emission inside the box. Thus, undesired electromagnetic emission energy from any electromagnetic emission source can be confined locally to prevent a possible problem of electromagnetic interference.

High frequency communication device

In a position detecting system used to monitor a suspicious person and to give an alarm by using a radar which transmits/receives a microwave or a millimeterwave, the shape of a detectable area of the radar and that of the area to be monitored are not always equal to each other, and thus, an alarm may be erroneously given in response to the object outside the area to be monitored. For its solution, the area to be monitored is surrounded by a plurality of reflectors, and the coordinate values of the reflectors and the detecting object are calculated based on the signals reflected from the reflectors and the detecting object and then compared. When the coordinate value of the detecting object is inside the area to be monitored, it is determined that the detecting object is an intruding person or the like and an alarm is given. When the coordinate value of the detecting object is outside the area to be monitored, it is determined that the detecting object is not an intruding person or the like and no alarm is given. In addition, if the calibration and self diagnosis of the radar are periodically performed by using at least one of the reflectors, it is possible to maintain the performance of the radar in an optimal state.

Detecting system

A monopulse radar system for detecting an azimuth depending upon amplitude difference or phase difference between signals respectively received by plural receiving antennas, includes: a transmitting array antenna and a receiving array antenna each including antenna elements forming an antenna train, at least one antenna switch disposed among the elements of the transmitting array antenna and/or the receiving array antenna, and a switch controller for turning ON/OFF the antenna switch to change an aperture length of the transmitting array antenna and/or the receiving array antenna thereby changing a beam shape thereof. The antenna elements of the transmitting array antenna and the receiving array antenna are formed on a dielectric substrate. A dielectric length between the antenna train formed by the antenna elements and the antenna switch is &#xbd; dielectric wavelength.

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Fuchu, Japan

Hiroshi Kondoh