JPWO2004066443A1 - Mobile communication antenna - Google Patents

Abstract

A first dielectric plate having a plurality of feed radiating elements and a second dielectric plate having a non-feed radiating element disposed at a position corresponding to the feed radiating element; By providing power supply means that can be turned on and off for the power supply radiation element in the first plate-like body, it is possible to transmit information of voice and images using a communication satellite in a mobile body such as an automobile or a hull. It is a mobile communication antenna suitable for the above.

Description

  The present invention relates to an antenna for mobile communication, and more particularly to an antenna that is relatively small and suitable for mobility to enable transmission of voice and image information using a communication satellite or the like in a mobile object such as an automobile or a ship.

Various types of communication antennas have been proposed and developed in the past. In recent years, planning and sophistication of mobile satellite communications have advanced, and multimedia information transmission such as voice and images using geostationary satellites has been developed. Technological development is being planned to make it possible for land and water vehicles.
In other words, the characteristics required for on-vehicle and other mobile antennas used for such mobile satellite communications vary depending on the application and system, but they require high gain over a wide range of angles, small size, and light weight. This is well understood by those skilled in the art. Many studies have been made on antennas having such characteristics, and there are cone beam antennas and satellite tracking antennas, but they still require a considerable size, and their purpose is appropriately set. Cannot be achieved.
The cone beam antenna has advantages such as being non-directional in the horizontal plane in the elevation direction of the satellite, having a wide beam width in the vertical plane, and eliminating the need for satellite tracking. On the other hand, the satellite tracking antenna has a satellite tracking function that directs the beam in the direction of the satellite even when the direction of the mobile station changes, and can achieve higher gain than a cone beam antenna. Has qualities. This tracking method includes mechanical tracking that performs satellite tracking by rotating the antenna itself using a motor or the like, and electronic tracking that performs beam operation electronically using a phase shifter, switching circuit, amplification circuit, and the like. . In particular, this electronic tracking requires a power distributor and phase shifter, or a switching circuit as compared with mechanical tracking, so that the power supply circuit is generally complicated.
However, it is clear that the mechanical tracking as described above tends to be complicated and large in terms of mechanism, the disadvantage of weight is unavoidable, it requires a certain driving force and has the disadvantage of noise generation. From any of the above, there is a disadvantage that is not preferable as a mechanism for such communication, and as a characteristic for use in mobile communication, high gain over a wide range of angles, compactness, lightness, etc. are required. Is difficult.
The satellite tracking antenna has a tracking function that directs the beam in the direction of the satellite, and can achieve higher gain than a cone beam antenna. Especially, electronic tracking is smaller and lighter than mechanical tracking. There are advantages such as high-speed tracking and maintenance-free because there is no motor or other operating part, but this electronic tracking requires a power distributor, phase shifter, or switching circuit compared to mechanical tracking. Therefore, there is a disadvantage that the power supply circuit is generally complicated. In addition, as the number of antenna elements increases, the number of phase shifters and switching circuits for controlling the power feeding of each element increases, and accordingly, there is a disadvantage that an increase in cost associated with them is inevitable.
In particular, in the case of an on-board antenna, the size and diameter of the antenna have various effects on the relationship with the running conditions of the vehicle body. In the case of an antenna exceeding tens of centimeters, there are considerable restrictions on the vehicle running speed. There are disadvantages such as high possibility of being caught by other objects during traveling.

The present invention has been devised by resolving the problems in the prior art as described above, and is a one-point feed type circularly polarized patch in which a plurality of rectangular patches are cut as a printed antenna. It has succeeded in obtaining an on-vehicle simple satellite tracking antenna that performs beam switching electrically in multiple directions by on / off power feeding control that does not require a phase shifter using an antenna. A first dielectric plate having a feed radiation element and a second dielectric plate having a parasitic radiation element disposed at positions corresponding to the plurality of feed radiation elements are coaxially arranged. The disadvantages described in the background art were eliminated by providing power supply means that can be set and turned on / off with respect to the power supply radiation element in the first plate-like body.
That is, a first dielectric plate having a plurality of feeding radiating elements and a second dielectric plate having a parasitic radiating element disposed at a position corresponding to the feeding radiating element are coaxially arranged. By setting and providing a feeding means that can be turned on / off with respect to the feeding radiation element in the first plate-like body described above, a circularly polarized patch array antenna with a plurality of elements is formed as a printed antenna, and a phase shifter is required With simple on / off power feeding control, the beam is switched electrically in multiple directions to form a vehicle-mounted simple satellite tracking antenna, and a useful reception purpose can be achieved easily and accurately.
According to the present invention, since there are four feed radiating elements and four parasitic radiating elements in the first and second dielectric plate-like bodies, proper feeding on / off can be performed by rotation by 90 °. An antenna is obtained. In addition, by changing the beam direction of the radiating element in accordance with the direction of an automobile or the like, it is possible to appropriately cover and receive all azimuth angles. The direction of the satellite can be obtained based on information such as a car navigation system.
By using a one-point-feed type circularly polarized patch antenna in which square patches in the feed radiating element and the non-feeding radiating element are cut, the setting direction of the element is specified to form an accurate setting relationship.
Since the first and second dielectric plate-like bodies are held and set at a predetermined interval by a plurality of dielectric interval holding means, they are disposed on the first and second dielectric plate-like bodies. A two-layered patch antenna relationship in which an appropriate arrangement setting relationship is formed and secured by the antenna radiating element and the parasitic element is secured, and a parasitic antenna is arranged to form a two-layered patch antenna.

FIG. 1 is a partially cutaway side view showing an example of a mobile communication antenna according to the present invention.
FIG. 2 is a perspective view showing the overall structural relationship of what is shown in FIG.
FIG. 3 is a schematic plan view schematically showing different embodiments of the general configuration according to the present invention.
FIG. 4 is an explanatory view summarizing an embodiment of a preferable feeding radiation element arrangement state with respect to the dielectric plate in the present invention.
FIG. 5 is an explanatory view of the reception action associated with the feeding of the right-handed circularly polarized wave and the left-handed circularly polarized wave with respect to the feed radiating element disposed on the dielectric plate.

A specific embodiment of the present invention as described above will be described with reference to the accompanying drawings. The basic embodiment of the present invention is as shown in FIGS. A second dielectric plate 2 having a plurality of parasitic radiating elements 12 arranged on the first dielectric plate 1 having a plurality of antenna radiating elements 11 formed on the same axis is coaxial. And are integrally connected and set by a plurality of insulating connecting members 3 provided on the peripheral sides of the dielectric plates 1 and 2.
In addition, on the first dielectric plate 1 as described above, four feeding and radiating elements 11 are arranged in an equiangular shape as shown in the figure, and a second dielectric plate formed on the upper portion. On the body 2, a parasitic element 12 is disposed at a position corresponding to the above-described feeding radiation element 11, and a feeding unit body 13 is provided for the feeding radiation element 11. Further, the first dielectric plate 1 and the second dielectric plate 2 are composed of a plurality of synthetic resin materials arranged on the peripheral sides of the plates 1 and 2. 3 are integrally assembled.
The antenna elements 11 and 12 as described above are circularly polarized antennas having a single-point feeding type in which notches 5 are formed at the corners of a rectangular patch in order to generate circularly polarized waves. Rotating 90 ° so that R or L is on the inner diameter side of the dielectric plate 1 (one end side of the antenna element 11), four elements are arranged as shown in FIG. Further, the two-layer structure in which the parasitic elements 12 to 12 are arranged in order to improve the gain is as described above. For beam switching, any one of the four elements 11 as described above is turned off. Thus, in the case of left-handed circularly polarized light, a beam having a peak in a direction deviated by −90 ° in the azimuth angle from the element whose power is turned off is formed. In the case of right-handed circular polarization, a beam having a peak in the opposite direction is formed.
More specifically, the feeding radiation element 11 and the parasitic radiation element 12 described above are one-point feeding type circles in which notched portions 11a or 12a are formed at opposite corner portions of a rectangular plate member so as to generate circular polarization. A polarization patch antenna is used, and four elements are arranged in a state in which this antenna element is rotated 90 ° so that the feeding point is inside. A patch antenna is formed by forming a two-layer structure of parasitic elements 12 for the purpose of gain improvement.
In the beam switching of the configuration as described above, by turning off the power supply to any one of the elements 11, in the case of left-handed circular polarization, the azimuth angle from the element 11 that has turned off the power supply A beam is formed in a direction shifted by −90 °. In this way, for example, all azimuth angles can be covered by switching four beams according to the direction of the automobile. As a method for obtaining the direction of the communication satellite, for example, a calculation method based on information such as a car navigation system can be used.
The antenna is designed by numerical calculation using the moment method from the viewpoint of calculation speed, and is optimized so that the axial ratio is minimized at the target frequency. However, since it is difficult to analyze a finite ground plane using the method of moments, it is possible to use an infinite ground plane, and to perform numerical calculations by the finite element method considering the finite ground plane depending on the prototype antenna, and to investigate the influence of the ground plane.
In addition, the inventors of the present invention specifically examined the radiation directivity and beam switching in the conical surface of the specific device according to the present invention, and all of them have been confirmed to have favorable results.
Further, the above description is about the specific equipment as shown in FIG. 1 and FIG. 2, but the two according to the present invention are two elements as shown in FIG. 3 (A) to (E). The case of ˜8 element type was also examined. In other words, it has been known that even in these cases, the functions or effects similar to those described above can be exhibited.
In addition, the inventors have summarized the results of studying preferable broadcast reception with a relatively compact configuration in accordance with the present invention as described above, and as shown in FIG. That is, in order to effectively achieve the reception as described above with a relatively small antenna, it is advantageous to appropriately select the number of the feed radiating elements 11 and the parasitic elements 12 and to regulate the direction and position of the notch 5. However, such examination results are summarized as shown in FIG. In other words, the number of the feed radiating elements 11 and the parasitic elements 12 is preferably about 2 to 4, and the elements 11 and 12 are appropriately arranged in a symmetrical and uniform state so that the reception purpose is effective and appropriate. Can be achieved. Although FIG. 5 shows feeding points R and L, only one of the feeding points R and L (for example, R) is adopted, and the other feeding point (for example, L ) Is used when circular polarization is reversed.
The arrangement of the feeding point for the feeding radiation element 11 in the first dielectric plate 1 or 2 is as shown separately in FIGS. 5A to 5C. A plurality of feed radiating elements 11 or parasitic elements 12 arranged in 1 or 2 are typically as shown in FIGS. 5A to 5C, and are fed at R and L. It is clear that the receiving action can be obtained with a proper circular polarization.
As the satellite broadcast receiving antenna prototyped by the present inventors, it is attached to a moving body such as a vehicle, and the first and second dielectric plates as described above have a diameter of about 18 cm. It is confirmed that the broadcast reception from the satellite can be effectively achieved by the above configuration, and it is such a small antenna and is covered with a radome, so it can withstand sunlight and wind pressure, The wind pressure and other resistances during running were low, and it was confirmed that effective reception purposes could be achieved under stable conditions. Because it is relatively small and uses an arc, it has little resistance when traveling such as a vehicle, and it is not likely to be caught even under conditions where tree branches are complicated, for example, it is suitable for traveling traveling It is clear.

  According to the present invention as described above, although it is possible to appropriately achieve broadcast reception by an artificial satellite or the like, it is small and lightweight and easily and easily equipped on a moving part such as an automobile or a hull. It is clear that effective and appropriate use can be achieved at least, and the equipment and configuration are simpler than those of conventional mechanical tracking and electronic tracking systems, and the above characteristics can be fully demonstrated. This is a highly effective invention.

Claims (8)

A first dielectric plate having a plurality of feed radiating elements and a second dielectric plate having a parasitic radiating element disposed at a position corresponding to the feed radiating elements are set coaxially. An antenna for mobile communication characterized in that a power feeding means that can be turned on / off with respect to the power feeding radiation element in the first plate-like body is provided. 2. The mobile communication antenna according to claim 1, wherein each of the first and second dielectric plate-like bodies has four feed radiating elements or four parasitic radiating elements. 2. The mobile communication antenna according to claim 1, wherein a one-point-feed type circularly polarized patch antenna is used in which a rectangular patch in the feed radiating element and the parasitic radiating element is cut. 3. The mobile communication antenna according to claim 2, wherein a one-point-feed type circularly polarized patch antenna is used in which a rectangular patch in the feed radiation element and the parasitic radiation element is cut. 2. The antenna for mobile communication according to claim 1, wherein the first and second dielectric plates are held and set at a predetermined interval by a plurality of dielectric interval holding means. 3. The mobile communication antenna according to claim 2, wherein the first and second dielectric plate-like bodies are held and set at a predetermined interval by a plurality of dielectric interval holding means. 4. The mobile communication antenna according to claim 3, wherein the first and second dielectric plate-like bodies are held and set at a predetermined interval by a plurality of dielectric interval holding means. 5. The mobile communication antenna according to claim 4, wherein the first and second dielectric plate-like bodies are held and set at a predetermined interval by a plurality of dielectric interval holding means.

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