JP4301041B2 - Integrated antenna - Google Patents

Description

  The present invention relates to an integrated antenna including a first antenna having directivity in a zenith direction, a second antenna having directivity in a horizontal direction, and a ground plate that acts as a ground of at least the first antenna. .

Conventionally, an integrated antenna is provided in which a plurality of antennas are arranged on the same ground plate, and the plurality of antennas are integrated (see, for example, Patent Document 1).
JP 2003-168917 A

  By the way, the integrated antenna that has been realized conventionally is one in which antennas having directivity in the zenith direction (elevation angle 90 degrees) are arranged on the same ground plate, and antennas having directivity in the zenith direction are integrated. On the other hand, with the recent development of wireless technology, there is a demand for integrating an antenna having directivity in the zenith direction and an antenna having directivity in the horizontal direction (0 degree of elevation). . However, if an antenna having directivity in the zenith direction and an antenna having directivity in the horizontal direction are to be integrated, it is necessary to arrange each antenna on the ground plate so as not to deteriorate the performance of each antenna.

  The present invention has been made in view of the above-described circumstances, and the object thereof is to ensure both the performances of the antenna having directivity in the zenith direction and the antenna having directivity in the horizontal direction while appropriately securing the respective performances. It is in providing the integrated antenna which can be integrated appropriately.

According to the first aspect of the present invention, the first antenna having directivity in the zenith direction is disposed near the center of the ground plate, and the second antenna having directivity in the horizontal direction is provided on one side of the ground plate. It is arrange | positioned in the edge part vicinity so that it may follow. The second antenna is arranged in the vicinity of the end portion along one side of the ground plate, and the folded structure has two side portions substantially parallel to one side and the other side of one element. It is formed of a modified folded dipole antenna that is formed and has a folding structure formed such that a part of each of two substantially parallel sides is substantially parallel to the ground plate .
Here, the directivity between the case where the antenna having directivity in the zenith direction is arranged near the center portion of the ground plate and the case where the antenna is arranged near the end portion will be described. Antenna having directivity in the zenith direction Is arranged near the center of the ground plate, the electric field is evenly radiated from the antenna to the ground plate, and the peak (maximum gain) of the directivity pattern is directed toward the zenith direction. On the other hand, when an antenna having directivity in the zenith direction is arranged near the end of the ground plate, the electric field is not evenly radiated from the antenna to the ground plate. However, the electric field is radiated in a biased manner with respect to the ground plate from the antenna. Click is to face in a direction deviated from the zenith direction, with the result that the performance of the antenna is reduced. On the other hand, the directivity between the case where the antenna having directivity in the horizontal direction is arranged near the center of the ground plate and the case where the antenna is arranged near the end will be explained. It will be directed in the direction and there will be no difference in antenna performance between the two.

  That is, according to the present invention, for an antenna having directivity in the zenith direction, the antenna performance can be appropriately ensured when arranged near the center of the ground plate, but near the end of the ground plate. The antenna performance cannot be ensured properly when the antenna is arranged in the horizontal direction. On the other hand, with respect to the antenna having directivity in the horizontal direction, the antenna is arranged near the center portion of the ground plate and the vicinity of the end portion. It was made paying attention to the point that the performance of an antenna can be ensured appropriately in both cases.

As a result, the first antenna having directivity in the zenith direction is disposed near the center of the ground plate, and the second antenna having directivity in the horizontal direction is disposed near the end portion along one side of the ground plate. By doing so, it is possible to appropriately integrate both of the antennas having directivity in the zenith direction and the antennas having directivity in the horizontal direction while appropriately securing the respective performances.

  According to the invention described in claim 2, the folded structure is formed so that the second antenna has two side portions substantially parallel to one side and the other side of one element. It consists of a folded dipole antenna. Accordingly, since the dipole antenna is an antenna that does not require a ground plate, the directivity pattern is not affected by the ground plate, and the directivity in the horizontal direction can be appropriately ensured. Moreover, in this case, since the folded structure is formed, the impedance of the antenna can be lowered by the folded structure, and the impedance of the antenna can be matched with the impedance of the coaxial cable connected to the antenna, Power efficiency can be appropriately ensured without requiring a matching circuit for matching impedance.

  According to the invention described in claim 3, the second antenna is formed with a folding structure so that a part of each of the substantially parallel two side portions is substantially parallel to the ground plate. It consists of a modified folded dipole antenna. Thereby, since the bending structure is formed, the dimension in the height direction of the second antenna can be reduced, and a low-profile structure as a whole integrated antenna can be realized.

  According to the invention described in claim 4, the second antenna is constituted by a dipole antenna composed of two elements. Thus, in the same manner as described in claim 2, the dipole antenna is an antenna that does not require a ground plate, so that the directivity pattern is not affected by the ground plate, and the directivity in the horizontal direction is not affected. Sex can be secured appropriately.

  According to the invention described in claim 5, the second antenna is constituted by a modified dipole antenna in which a bent structure is formed so that a part of each element is substantially parallel to the ground plate. Yes. As a result, in the same manner as described in the third aspect of the present invention, since the bent structure is formed, the dimension in the height direction of the second antenna can be reduced, and the overall integrated antenna can be reduced. A posture structure can be realized.

  According to the invention described in claim 6, the first antenna is constituted by a GPS antenna or a VICS antenna, and the second antenna is constituted by a mobile phone antenna. Thereby, it can be used as a vehicle-mounted integrated antenna that can be mounted on a vehicle in which a GPS receiver, a VICS receiver, and a mobile phone are mounted.

  Hereinafter, an embodiment in which an antenna of the present invention is applied to an in-vehicle integrated antenna that can be mounted on a vehicle will be described with reference to the drawings. FIG. 1 schematically shows the overall configuration of the integrated antenna. The in-vehicle integrated antenna 1 includes an antenna 2 having directivity in the zenith direction (first antenna in the present invention), an antenna 3 having directivity in the horizontal direction (second antenna in the present invention), a grant A plate 4 is provided.

  The antenna 2 having directivity in the zenith direction is composed of a patch antenna 7 in which a radiating element 5 made of a metal plate is mounted on a dielectric 6 made of resin, for example, and is arranged at the center of the ground plate 4. . In this case, the antenna 2 having directivity in the zenith direction is, for example, a GPS antenna for receiving GPS radio waves transmitted from GPS satellites or a VICS antenna for receiving VICS radio waves transmitted from a service center. is there. On the other hand, the antenna 3 having directivity in the horizontal direction is composed of a modified folded dipole antenna (see FIG. 2 (a)) or a modified folded monopole antenna (see FIG. 2 (b)). It is arranged at the left end portion in FIG. In this case, the antenna 3 having directivity in the horizontal direction is, for example, a mobile phone antenna for transmitting and receiving radio waves in the “800 MHz” band used in mobile phones.

  The structure of the modified folded dipole antenna and the modified folded monopole antenna will be specifically described. As shown in FIG. 2A, the modified folded dipole antenna 11 is composed of a transmission line antenna composed of one element, and is substantially The folded structure 14 is formed on one side so as to have two parallel sides 12, 13, and the folded structure 17 is formed on the other side so as to have two substantially parallel sides 15, 16. Also formed. The two side parts 12 and 13 are bent at substantially right angles by the folding structures 18 and 19 so that a part of them is parallel to the ground plate 4 and the two side parts. 15 and 16 are also bent at substantially right angles by the folding structures 20 and 21 so that a part of them is parallel to the ground plate 4.

  In this case, for example, in the case of a mobile phone antenna for transmitting and receiving radio waves in the “800 MHz” band, the length from the end portion 12a of the side portion 12 to the central portion of the folded structure 14 (“L1” in FIG. 2A). 2), the length from the center of the folded structure 14 to the center of the element (see “L2” in FIG. 2A), the length from the center of the element to the center of the folded structure 17, the folded structure The length from the center portion of 17 to the end portion 15a of the side portion 15 is configured by multiplying the wavelength of the radio wave in the “800 MHz” band by “¼”. That is, the modified folded dipole antenna 11 is configured to have the same length as the wavelength of the radio wave in the “800 MHz” band. The coaxial cable 22 has an inner conductor 22a connected to one end side of the element, that is, the end 12a side of the side portion 12, and an outer conductor 22b connected to the other end side of the element. That is, the side 15 is connected to the end 15 a side.

  On the other hand, as shown in FIG. 2 (b), the modified folded monopole antenna 31 is composed of a transmission line antenna composed of one element, and has a folded structure 34 having two substantially parallel sides 32 and 33. The two side portions 32 and 33 are bent at substantially right angles by the folding structures 35 and 36 so that part of the two side portions 32 and 33 is parallel to the ground plate 4. Also in this case, for example, in the case of a mobile phone antenna for transmitting and receiving radio waves in the “800 MHz” band, the length from the end portion 32a of the side portion 32 to the central portion of the folded structure 34 (in FIG. 2B, “ L3 ”), the length from the center portion of the folded structure 34 to the end portion 33a of the side portion 33 (see“ L4 ”in FIG. 2B) is set to“ 1 / MHz ”in the wavelength of the radio wave in the“ 800 MHz ”band. The length is multiplied by “4”. In other words, the modified folded monopole antenna 31 has a length that is obtained by multiplying the wavelength of the radio wave in the “800 MHz” band by “½”. The coaxial cable 22 has an inner conductor 22a connected to one end side of the element, that is, the end 32a side of the side 32, and an outer conductor 22b connected to the other end side of the element. That is, the side 33 is connected to the end 33 a side.

  Here, the reason why the antenna 2 having directivity in the zenith direction is arranged at the center of the ground plate 4 and the antenna 3 having directivity in the horizontal direction is arranged at the end of the ground plate 4 will be described below. Explained.

  The inventors have a case where the antenna 2 having directivity in the zenith direction and an antenna 3 having directivity in the horizontal direction are arranged at the center portion and at the end portion of the ground plate 4. The directivity pattern was measured.

  FIG. 3 shows the measurement results of the directivity patterns when the antenna 2 having directivity in the zenith direction is arranged at the center portion and at the end portion of the ground plate 4. As shown in FIG. 4A, when the antenna 2 having directivity in the zenith direction is arranged at the center of the ground plate 4, an electric field is radiated from the antenna 2 to the ground plate 4 evenly. Therefore, the peak (maximum gain) of the directivity pattern is directed to the zenith direction (see “arrow A” in FIG. 3), whereas, as shown in FIG. When the antenna 2 having directivity in the zenith direction is disposed at the end of the ground plate 4, an electric field is not radiated from the antenna 2 to the ground plate 4 uniformly, but from the antenna 2 to the ground plate. 4, the electric field is radiated in a biased manner, and in some cases, the electric field wraps around to the back side of the ground plate 4, so that the peak of the directivity pattern is directed away from the zenith direction. (See “Arrow B” in FIG. 3.) .

  On the other hand, FIG. 5 shows the measurement results of the directivity pattern when the antenna 3 having directivity in the horizontal direction is arranged at the center portion and at the end portion of the ground plate 4. . Here, the measurement results in the case where the antenna 3 having directivity in the horizontal direction is constituted by the modified folded monopole antenna 31 are shown. The directivity between the case where the deformed folded monopole antenna 31 is arranged at the center part and the case where the modified folded monopole antenna 31 is arranged at the end part will be described. Thus, there is no difference in antenna performance between the two.

  That is, with respect to the antenna 2 having directivity in the zenith direction, the performance of the antenna 2 can be appropriately ensured when the antenna 2 is disposed in the center portion of the ground plate 4, but in the vicinity of the end portion of the ground plate 4. When the antenna 3 is disposed, the performance of the antenna 2 cannot be ensured appropriately. On the other hand, the antenna 3 having directivity in the horizontal direction is compared with the case where the antenna 3 is disposed at the center portion of the ground plate 4 and the end portion. Therefore, the performance of the antenna 3 can be appropriately ensured both in the case where the antenna 3 is disposed.

  Here, FIG. 6 shows the configuration of FIG. 1 described above, that is, the antenna 2 having directivity in the zenith direction is arranged at the center of the ground plate 4 and the antenna 3 having directivity in the horizontal direction is the ground plate. 4 shows a measurement result of measuring the directivity pattern of the antenna 2 having directivity in the zenith direction in the configuration arranged at the end of FIG. 4, and FIG. 7 shows the directivity in the horizontal direction in the configuration of FIG. The measurement result which measured the directivity pattern of the antenna 3 which has is shown. Here, the measurement results in the case where the antenna 3 having directivity in the horizontal direction is configured from the modified folded dipole antenna 11 are shown. 6 and 7, according to the configuration of the present embodiment, the performance of the antenna 2 having directivity in the zenith direction can be appropriately ensured, and the antenna 3 having directivity in the horizontal direction can be secured. It is possible to appropriately secure the performance of the system.

  FIG. 8 shows measurement results obtained by measuring directivity patterns for each of the modified folded dipole antenna 11 and the modified folded monopole antenna 31. As is clear from FIG. 8, when the directivity pattern of the modified folded dipole antenna 11 and the directivity pattern of the modified folded monopole antenna 31 are compared, the modified folded dipole antenna 11 is more directional than the modified folded monopole antenna 31. The sex pattern is excellent. This is because the monopole antenna is an antenna that requires a ground plate, and its directivity pattern is affected by the ground plate 4, whereas the dipole antenna is an antenna that does not require a ground plate. This is because the directivity pattern is not affected by the ground plate 4.

By the way, the above describes the case where the antenna 3 having directivity in the horizontal direction is configured from the modified folded dipole antenna 11 and the modified folded monopole antenna 31. As shown in FIG. The folded dipole antenna 11 may be formed of a modified dipole antenna 41 having a shape in which the folded structure is omitted, and the folded structure of the modified folded monopole antenna 31 is omitted as shown in FIG. You may comprise from the deformation | transformation monopole antenna 51 which makes the shape. In this case, each of the two elements constituting the modified dipole antenna 41 has its full length (see “L5” in FIG. 9A) multiplied by “¼” to the wavelength of the radio wave in the “800 MHz” band. One element constituting the modified monopole antenna 51 has a total length (refer to “L6” in FIG. 9B) of “1/4” to the wavelength of the radio wave in the “800 MHz” band. ”Is multiplied by“ ”.
If there is no restriction in the height direction, a dipole antenna or a monopole antenna having a shape in which the bending structure is omitted may be used.

  As described above, according to the present embodiment, in the in-vehicle integrated antenna 1, the antenna 2 having directivity in the zenith direction is disposed in the center portion of the ground plate 4, and the antenna 3 having directivity in the horizontal direction is provided. Since it is configured to be disposed at the end of the ground plate 4, both the antenna 2 having directivity in the zenith direction and the antenna 3 having directivity in the horizontal direction are appropriately secured while ensuring both performances. Can be integrated.

  In addition, since the antenna 3 having directivity in the horizontal direction is composed of a dipole antenna, the dipole antenna is an antenna that does not require the ground plate 4, so that the directivity pattern is affected by the ground plate 4. Therefore, the directivity in the horizontal direction can be appropriately ensured.

  Further, since the antenna 3 having directivity in the horizontal direction is formed of a folded dipole antenna having a folded structure, the impedance of the antenna 3 can be lowered by the folded structure, and the impedance of the antenna 3 can be reduced to the impedance of the coaxial cable 22. The power efficiency can be appropriately ensured without requiring a matching circuit for matching the impedance.

  Furthermore, since the antenna 3 having directivity in the horizontal direction is composed of a modified folded dipole antenna having a folded structure, the height dimension of the antenna 3 can be reduced, and the vehicle-mounted integrated antenna 1 as a whole A low-profile structure can be realized.

The present invention is not limited to the above-described embodiment, and can be modified or expanded as follows.
For example, an ETC antenna used in an automatic toll collection system may be applied as an antenna having directivity in the zenith direction. For example, a wireless LAN used in a wireless LAN as an antenna having directivity in the horizontal direction. A configuration to which a general antenna is applied may be used.
Not only the configuration in which the antenna having directivity in the zenith direction is directly disposed on the ground plate, but also the configuration in which the antenna having directivity in the zenith direction is disposed on the ground plate through the space, or the zenith direction Alternatively, the antenna having directivity may be arranged on the ground plate via another member such as a printed wiring board or a shield case.

The perspective view which shows the structure of one Embodiment of this invention roughly A perspective view schematically showing the configuration of a modified folded dipole antenna and a modified folded monopole antenna The figure which shows the directivity pattern of the antenna which has directivity in the zenith direction The figure which shows schematically the aspect by which the antenna which has directivity in a zenith direction is arrange | positioned in the center part of a ground plate, and the aspect arrange | positioned in an edge part The figure which shows the directivity pattern of the antenna which has directivity in a horizontal direction The figure which shows the directivity pattern of the antenna which has directivity in the zenith direction in this embodiment. The figure which shows the directivity pattern of the antenna which has directivity in the horizontal direction in this embodiment. Diagram showing the directivity pattern of a modified folded dipole antenna and the directivity pattern of a modified folded monopole antenna A perspective view schematically showing the configuration of a modified folded dipole antenna and a modified folded monopole antenna

Explanation of symbols

  In the drawings, 1 is an in-vehicle integrated antenna (integrated antenna), 2 is an antenna having directivity in the zenith direction (first antenna), 3 is an antenna having directivity in the horizontal direction (second antenna), and 4 is Ground plate 11 is a modified folded dipole antenna, 12 and 13 are sides, 14 is a folded structure, 15 and 16 are sides, 17 is a folded structure, 18 to 21 are folded structures, and 41 is a modified dipole antenna.

Claims (7)

An integrated antenna comprising a first antenna having directivity in the zenith direction, a second antenna having directivity in the horizontal direction, and a ground plate that acts as a ground of at least the first antenna,
The first antenna is disposed near the center of the ground plate,
The second antenna is disposed in the vicinity of the end portion along one side of the ground plate, and is folded back so as to have two side portions substantially parallel to one side and the other side of one element. The structure is formed and a folded folded dipole antenna is formed in which a folding structure is formed so that a part of each of two substantially parallel sides is substantially parallel to the ground plate. Integrated antenna featured. An integrated antenna comprising a first antenna having directivity in the zenith direction, a second antenna having directivity in the horizontal direction, and a ground plate that acts as a ground of at least the first antenna,
The first antenna is disposed near the center of the ground plate,
The second antenna is disposed near an end portion along one side of the ground plate, that have folding structures are formed to be substantially parallel to a part of the ground plate of the side portions integrated antenna, wherein a call. The integrated antenna according to claim 2,
The second antenna consists of a single element, integration, characterized in that it is composed of a deformed folded monopole antenna folded-back structure is formed so as to have a substantially two parallel sides antenna. The integrated antenna according to claim 2 ,
The said 2nd antenna is comprised from the deformation | transformation monopole antenna which consists of one element, The integrated antenna characterized by the above-mentioned. The integrated antenna according to claim 2 ,
The said 2nd antenna is comprised from the deformation | transformation dipole antenna which consists of two elements, The integrated antenna characterized by the above-mentioned. The integrated antenna according to any one of claims 1 to 5,
The first antenna includes a GPS antenna and a VICS antenna,
The integrated antenna is characterized in that the second antenna is composed of a mobile phone antenna. The integrated antenna according to claim 1 or 5 ,
The dipole antenna is fed by a side perpendicular to the ground plate.

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