Kabushiki Kaisha Toyota Chuo Kenkyusho

Other

Denso Corporation

Kunitoshi Nishikawa

Toshiaki Watanabe

Masaru Ogawa

Kazuo Sato

Tomohisa Harada

Mitoshi Fujimoto

Hideo Iizuka

Yoshikazu Asano

Shigeki Ohshima

Eiji Teramoto

Kunio Sakakibara

Tomoaki Hirako

A feed probe (), a semicylindrical sub-reflector () forming a primary radiator together with the feed probe (), and a main reflector () arranged such that mirror surfaces of said main reflector () and the sub-reflector face across the feed probe () are all disposed on a ground plate (a recfector face) (). The main reflector () has a predetermined focal point or focal line on which the feed probe () is located, and is mounted on the ground plate () at a predetermined installation angle &#x3b8;. A converter () for converting linearly and circularly polarized waves is provided on the mirror surface of the main reflector (). The converter () is composed of a plurality of grooves () and ridges () formed between the grooves, so that a wave component orthogonal to the grooves is reflected at the bottom of the grooves while a wave component parallel to the grooves is reflected on the ridge surface, thereby causing a phase difference according to the height H of the grooves when a radio wave is reflected on the main reflector to thereby perform linear to circular polarization conversion.

Antenna system

In a waveguide-transmission line transition, a short-circuiting metal layer is formed on one surface of a dielectric substrate, and the short-circuiting metal layer has a slit in which a strip line is disposed. The short-circuiting metal layer and the strip line are disposed on the same plane with a predetermined gap formed therebetween. A grounding metal layer having a shape substantially congruent with the cross-sectional shape of the opening surface of the waveguide is formed on the other surface of the dielectric substrate. The short-circuiting metal layer, the grounding metal layer, and the waveguide are maintained at the same potential by metal embedded in through-holes provided along the circumferential edge of the dielectric substrate. Further, a matching element is disposed on the surface of the dielectric substrate on which the grounding metal layer is formed. This structure enables formation of substantially the entirety of the transition, except the waveguide, on the same substrate on which a microwave or millimeter-wave circuit or a planar antenna are formed.

Waveguide-transmission line transition having a slit and a matching element

Ten radiation antenna elements project from a straight feeder stripline. A first set of radiation antenna elements each having a rectangular shape project from a first side edge of the feeder stripline such that the radiation antenna elements incline at an angle of about 45 degrees. The distance between adjacent radiation antenna elements is equal to an guide wavelength &lgr; and the length of each radiation antenna element is equal to &lgr; /2. Similarly, a second set of radiation antenna elements each having a rectangular shape project from a second side edge of the feeder stripline. Each of the radiation antenna elements in the second set is disposed to be separated by &lgr; /2 from a corresponding one of the radiation antenna elements in the first set. Each of the radiation antenna elements is connected to the corresponding side edge of the feeder stripline via a corner thereof.

Microstrip array antenna

There is provided an antenna system applicable to an in-vehicle satellite tracking antenna system. A feed probe (,) is inserted into a ground plate (,) from a lower surface of the ground plate (,) toward an upper surface to protrude from the upper surface. A semicylindrical sub-reflector (,) forming a primary radiator together with the feed probe (,) is arranged on the upper surface of the ground plate (,) in the vicinity of the feed probe (,), and a main reflector (,) is arranged on the ground plate (,) such that mirror surfaces of the reflectors face to each other across the feed probe (,). The main reflector (,) is parabolic in at least one axis, and has a predetermined focal point or a predetermined focal line. The main reflector (,) is standing on the ground plate (,) such that the feed probe (,) is positioned on the focal point or the focal line, which is mounted on the ground plate (,) at a predetermined installing angle &thgr; so that an elevation angle of the antenna is directed in a direction that receives radio waves or a direction that radiates radio waves. Tracking of the antenna system with respect to an azimuth is carried out by turning the ground plate (,) in a fashion being out of contact with the feed probe (,). By virtue of the above construction, the antenna system can be downsized or given a low profile.

A directional beam antenna device includes: an antenna supporting member which is supported on a base in such a manner as to be rotatable about a first rotational axis; an antenna portion which is supported on the antenna supporting member in such a manner as to be rotatable about a second rotational axis which is perpendicular to an antenna aperture and is inclined at a first angle with respect to the first rotational axis, the direction of an antenna beam being inclined at a second angle with respect to the second rotational axis; a first driving unit for rotating the antenna supporting member about the first rotational axis with respect to the base; and a second driving unit for rotating the antenna portion about the second rotational axis with respect to the antenna supporting member. A directional beam controlling apparatus is provided with a controlling unit for controlling an elevation angle of the antenna beam to a target value by causing the second driving unit to rotate the antenna portion with respect to the antenna supporting member, and for controlling an azimuth angle of the antenna beam to a target value by causing the first driving unit to rotate the antenna supporting member with respect to the base.

Directional beam antenna device and directional beam controlling

A control portion performs gyro control at control intervals of .DELTA.t, by using -.omega.G, which is obtained by inverting the polarity of an angular rate .omega.G outputted from an angular rate sensor portion. On the other hand, a receiving level is detected at constant control intervals of .DELTA.T (=M.DELTA.t: M is an integer). The rotation of an antenna portion is controlled by using .omega.s, if the receiving level has increased, or by using -.omega.s, if the receiving level has decreased, i.e. by step track control. By accumulating the control amount .+-..omega.s for a predetermined long time period of N.DELTA.T, accumulation of an error contained in each angular rate .omega.G is obtained. The accumulated value is then divided by N to calculate an error .DELTA..omega.G contained in .omega.G. This error .DELTA..omega.G is used to compensate the actual error, so that the gyro control can be made more accurate.

Tracking antenna system

In an annular microstrip antenna element, an annular radiant conductor plate is mounted on a ground conductor plate via a dielectric layer. A coaxial transmission line is provided, whose external conductor is connected to the ground conductor plate, and whose central conductor is connected to the radiant conductor plate, via a feeding point, with a pair of microstrip lines. The pair of microstrip lines extend from the feeding point to two connecting points on the radiant conductor plate, forming an angle between them like a V shape. By varying the angle, it is possible to adjust the input impedance of the annular microstrip antenna element at the feeding point, so that impedance matching with the coaxial transmission line is achieved. In a radial line antenna system comprising a plurality of the antenna elements, the antenna elements are mounted on concentric circles with a constant space between the adjacent antenna elements, thereby reducing undesirable electromagnetic coupling.

Annular microstrip antenna element and radial line antenna system

An antenna is divided into a plurality of sub-arrays which are arranged parallel to each other on a turntable. At least one of the sub-arrays is laterally divided into sub-array sections. Reception signals from these sub-array sections are compared with each other to detect a phase difference therebetween. This phase difference is utilized to control the beam direction of the antenna such that the antenna can be properly oriented to the satellite at all times.

In mobile communications, it is required that the beam direction is maintained to track the desired direction as the mobile is moving. For such a purpose, the mobile includes an angular rate sensor mounted therein which detects the state of turn in the mobile and to control the beam direction of the antenna in accordance with the state of turn as well as the strength of radiowave received by a receiver in the mobile. Antenna elements are in the form of microstrip antenna and are arranged in plane on the same dielectric substrate. Feeding and drive circuit layers for controlling the transmission and reception at the antenna elements are stacked into a single layered unit. This enables the antenna system to be formed into a low-profile structure. The dielectric substrate of the microstrip antenna element is formed by stacking a plurality of dielectric substrate different in dielectric constant from one another. It is thus intended that the band width of the antenna is increased and that the mutual coupling between the antenna elements is reduced to prevent the gain of the antenna from being lowered. Furthermore, the position of feed points in the antenna element are rotated against each adjacent antenna element. This can improve the axial ratio in the array antenna over a wide band width.

Mobile antenna system

An antenna mounted on a mobile. In a first structure, a radiating element is composed of a ground plate, a vertical conductor plate and a parallel conductor plate placed on the ground plate with a predetermined space therebetween in such a manner as to have a T-shaped section and placed on the ground plate with a narrow space therebetween, and posts for connecting the edges of the parallel plate to the ground plate. Power is fed to the lower edge of the vertical conductor plate, thereby enabling a plurality of current paths to be formed in the radiating element and, hence, resonance in a wide frequency band. In a second structure, a radiating element has a conductor plate for impedance compensation in the vicinity of the feeding point of a conductor which is bent in the form of substantially a box, thereby enabling the reduction of the entire size and sufficiently increasing the length of the radiating element. In a third structure, a radiating element having the first structure and a radiating element having the second structure are adopted for effecting diversity reception.

Low profile antenna for land mobile communications

A land vehicle navigation system is adapted to display the present position of a vehicle by receiving signals from a combination of satellites under the global positioning navigation system. The present position of the vehicle is displayed on a screen, superposed over map data. To obtain the best global positioning data, the combination of satellites is selected in connectio with the visibility. To perform the positive reception of signals from the satellites as the vehicle is running in an urban area, data relating to the building height around the area can be obtained from a geographical information section including data indicative of the map and the building height distribution with respect to the area to determine the visibility.

Land vehicle navigation system

An antenna to be mounted on a vehicle. The antenna includes a ground plate with an L-shaped radiator plate and an L-shaped sub-radiator plate. One leg of the radiator plate and sub-radiator plate are parallel to the ground plate. The parallel legs are spaced from the ground plate. The other leg is perpendicular to the ground plate. The perpendicular leg is separated from the ground plate by a small gap. The two legs are opposed to each other with a gap between the legs parallel to the ground plate. In some embodiments, filler is placed between the plates.

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Aichi-ken, Japan

Kunitoshi Nishikawa