JP4927677B2 - Transmitting antenna device - Google Patents

Description

  The present invention relates to a multi-surface combining type transmission antenna device suitable for transmitting a plurality of broadcast waves having different radio wave frequencies.

  As a transmission antenna device suitable for transmission of a plurality of TV broadcast waves, an antenna unit having the same number of three or more planes that respectively constitute a plurality of multi-plane synthetic antennas having different transmission radio wave frequencies, and a column at the top of the broadcast tower There is known a transmitting antenna device that is circularly arranged at regular angular intervals in a predetermined order within a plane (see, for example, Patent Document 1). This type of transmission antenna device can be installed with a plurality of multi-plane synthetic antennas having different transmission radio frequencies at the same height (ground height), and is attracting attention as a space-sharing antenna.

In addition, by changing the array diameter (distance from the center of the column supporting the antenna) of each of the plurality of multi-surface synthetic antennas according to the transmission radio frequency, the horizontal plane orientation of each multi-surface synthetic antenna is changed. It is also proposed to guarantee the property (see, for example, Patent Document 2).
Japanese Patent No. 3374111 Japanese Patent No. 3500385

  However, when the arrangement diameter of the plurality of antenna units constituting each of the plurality of multi-sided combined antennas is changed according to the transmission radio frequency, particularly when the difference between the transmission radio frequencies is large, the arrangement of the plurality of antenna units There is a problem that the horizontal plane directivity of the multi-sided synthetic antenna on the smaller diameter side is greatly deteriorated. In other words, in the above case, the antenna unit with the larger array diameter is positioned on both front sides of the antenna unit with the smaller array diameter. Then, the individual antenna characteristics of the antenna unit with the smaller array diameter change under the influence of the antenna unit with the larger array diameter. As a result, it cannot be denied that the horizontal plane directivity of the multi-plane synthetic antenna constituted by the antenna unit having the smaller array diameter is deteriorated. In particular, there arises a problem that the electric field strength in the horizontal plane of the multi-plane synthetic antenna having a small array diameter of the antenna unit varies, for example, by about 6 dB depending on its direction.

  The present invention has been made in consideration of such circumstances, and the object thereof is to place a plurality of antenna units respectively constituting a plurality of multi-sided composite antennas having different transmission radio frequencies at the same height position in a predetermined order. In the transmitting antenna device configured to be arranged in an annular shape at equal angular intervals, the horizontal plane directivity of each of the multi-surface synthetic antennas is particularly determined even when the transmission radio frequency difference between the multi-surface synthetic antennas is large. An object of the present invention is to provide a transmission antenna device that can be kept in good condition.

In order to achieve the above-described object, the present invention provides a predetermined number of antenna units having the same number of three or more planes, each of which constitutes a plurality of multi-plane synthetic antennas having different transmission radio frequencies, in a horizontal plane centered on a column such as a broadcasting tower. In the transmitting antenna device circularly arranged at equal angular intervals in the order of
A plurality of antenna units constituting each of the plurality of multi-surface synthetic antennas are provided by being tilted so that the angles of the antenna surfaces are different from each other in the vertical direction between the multi- surface synthetic antennas of the plurality of multi-surface synthetic antennas having different transmission radio frequencies. It is characterized by that.
The plurality of antenna units that constitute each of the plurality of multi-surface synthetic antennas may be provided with the antenna surface tilted in the vertical direction at an angle determined for each transmission radio frequency.

  Incidentally, the plurality of antenna units constituting each of the plurality of multi-surface synthetic antennas are arranged at equal angular intervals on a circumferential surface having a diameter determined according to the transmission radio frequency. In this case, the plurality of antenna units may be provided in multiple stages in the vertical direction at each position determined by dividing them into equiangular intervals on the circumferential surface having a diameter determined according to the transmission radio frequency. good.

  For each antenna unit, for example, a predetermined number of double-loop antennas having an antenna length corresponding to the transmission radio frequency is configured by providing an antenna surface parallel to the main surface of the reflector on a flat reflector. What is necessary is just to implement | achieve as what radiates | emits the electromagnetic wave which has a main lobe in the direction perpendicular | vertical with respect to the main surface of the said reflecting plate.

  According to the transmission antenna device having the above-described configuration, the plurality of antenna units that respectively configure the plurality of multi-surface synthetic antennas are provided so as to be tilted so that the antenna surfaces form different angles in the vertical direction between the multi-surface synthetic antennas. Therefore, interference between these antenna units can be effectively suppressed. In particular, the antenna characteristics of the antenna unit with a small array diameter do not change under the influence of the antenna unit with a large array diameter positioned on the front side of the antenna unit with a small array diameter. It is possible to effectively prevent the degradation of the horizontal plane directivity of the multi-plane synthetic antenna constituted by the antenna unit.

  Therefore, even a multi-surface synthetic antenna having a smaller array diameter of a plurality of antenna units can have a horizontal plane directivity having smooth omnidirectionality with little change in radio wave intensity in the circumferential direction. Therefore, the horizontal plane directivities of a plurality of multi-surface synthetic antennas having different transmission radio wave frequencies installed at the same height position can be made substantially the same.

Hereinafter, a transmission antenna apparatus according to an embodiment of the present invention will be described with reference to the drawings.
This transmission antenna apparatus basically has an antenna unit with three or more planes that respectively constitute a plurality of multi-plane synthetic antennas having different transmission radio wave frequencies, with a support P provided at the top of a broadcast tower or the like as a center. In a horizontal plane, a circular arrangement is arranged in a predetermined order at regular angular intervals. Specifically, for example, each of the 20 antenna units a and b constituting the two multi-plane combined antennas A and B having different UHF band broadcast channels are alternately arranged in an annular shape as shown in FIG. Arranged at angular intervals.

  By the way, when the broadcasting channels of the two multi-plane composite antennas A and B are 29ch and 34ch in the UHF band, for example, the 20 antenna units a constituting the multi-plane composite antenna A of 29 ch have a distance of 3410 mm from the center of the column P. They are arranged at intervals of 18 ° on the separated circumferential surfaces. Further, the 20 antenna units b constituting the 34-channel multi-sided composite antenna B have a 9 ° deviation from the mounting position of the antenna unit a, for example, a circumference separated by a distance of 3230 mm from the center of the column P. They are arranged on the surface at intervals of 18 °. That is, although these antenna units a and b have different arrangement diameters from the column P, they are alternately arranged around the column P in an annular shape at intervals of 9 °.

  More specifically, the above-described two multi-surface synthetic antennas A and B are prepared, for example, as 20 sets of antenna units a and b arranged in four stages in the vertical direction as shown in FIG. As described above, the sets of the antenna units a and b are alternately arranged at intervals of 9 ° in the circumferential direction with the support column P as the center. Note that each of these antenna units a and b has a function of increasing the antenna gain by cooperating with each other, and equivalently, one antenna having a high antenna gain. It can be understood as units a and b.

  In this way, a plurality of antenna units a and b are alternately arranged at equal angular intervals in the circumferential direction, and two polyhedral synthetic antennas A and B having different transmission frequencies are formed at the same height position. 2, the present invention is characterized in that, as shown in FIG. 2, a plurality of antenna elements a forming a multi-plane synthetic antenna A and a plurality of antenna elements b forming a multi-plane synthetic antenna B are provided. The antenna surface is tilted with respect to the support column P so that the angle of the antenna surface is different in the vertical direction. Of course, it is also possible to tilt only the antenna surface of the antenna element a (b) in one multi-plane synthetic antenna A (B) in the vertical direction.

  In this example, the antenna surfaces of a plurality of antenna elements a forming one multi-plane composite antenna A are tilted upward by 5 °, and the antenna surfaces of a plurality of antenna elements b forming the other multi-plane composite antenna B are directed downward. Tilt 5 °. The antenna elements a and b have an angle of 10 ° in the direction of the antenna surface. With respect to this deviation angle, the difference between the broadcast channels allocated to the two multi-surface synthetic antennas A and B, that is, the difference in the transmission radio frequency, the size of each antenna element a and b, and the arrangement between the antenna elements a and b What is necessary is just to set according to a space | interval etc., for example, it is enough to set in the range of about 3-10 degrees.

  As described above, the antenna elements a and b arranged in an annular shape around the support P are basically configured as shown in FIGS. 3A and 3B in plan and sectional configurations, for example. An arc-shaped loop having a circumferential length L of approximately one wavelength λ of each of the radio wave frequencies fa and fb on a plate-like reflector 11 whose main surface is formed by bending both edges in the longitudinal direction at approximately 45 °. The loop surface of the two-element twin loop antenna 13 in which the antenna element portion 12 is formed is provided in parallel with the main surface. The antenna elements a and b having such a configuration excite the double loop antenna 13 in a direction perpendicular to the main surface of the reflector 11 (the loop surface of the loop antenna element portion 12) from the double loop antenna 13. Radiates radio waves. Then, in the horizontal plane direction, for example, the antenna elements a and b having a single directivity as shown in FIG. 4 are realized. In the figure, reference numeral 14 denotes a protective cover (ray dome) provided so as to cover the twin loop antenna 13. The protective cover 14 protects the dual loop antenna 13 from rain and wind, snow, and dust.

  In addition, you may make it strengthen the directivity of the electromagnetic wave radiated | emitted from the antenna elements a and b by providing the several twin loop antenna 13 in parallel. Of course, the antenna elements a and b can be realized by using not only the four-element double-loop antenna 13 but also a two-element double-loop antenna or a six-element double-loop antenna. Further, the protective cover 14 can be realized as a flat antenna in appearance by reducing the overall unevenness by attaching the edges to both ends of the reflector 11.

  FIG. 5 shows the directivity characteristics in the horizontal plane of the multi-plane synthetic antenna B in the transmission antenna apparatus configured as described above. FIG. 6 shows the directivity characteristics in the horizontal plane of the polyhedral synthetic antenna A in the transmission antenna device. As shown in FIGS. 5 and 6, the directivity characteristics of two multi-plane synthetic antennas A and B having different transmission radio frequencies arranged at the same height position are relative electric field intensities over the entire circumferential direction. Was suppressed to −3 dB or less, and it was confirmed that the entire display was smooth and had good omnidirectionality.

  In FIG. 5, the directional characteristics of the multi-plane synthetic antenna B when the antenna surfaces of the antenna elements a and b are not tilted, that is, when the antenna surfaces of the antenna elements a and b are provided in parallel, are indicated by a broken line Y. . In this case, the directional characteristic Y of the 34 ch multi-plane composite antenna B configured by arranging the antenna elements b inside each antenna element a of the 29 ch multi-plane composite antenna A is small in the arrangement diameter from the support column. For each direction between the elements b (direction in which the antenna element a is arranged), a change in relative electric field strength of about −5 dB occurs, and overall, the directivity characteristic with large unevenness is shown, and there remains a problem in terms of practicality. It is.

  The deterioration of the directivity characteristics of the 34-channel multi-surface composite antenna B is caused by the fact that the antenna element a of the 29-channel multi-surface composite antenna A having a larger array diameter than the antenna element b of the multi-surface composite antenna B is This is considered to be due to the influence of the reflector of the antenna element a of the multi-sided composite antenna A because it is positioned on the front side of the element b.

  In this regard, according to the transmitting antenna device according to the present invention, the antenna element b of the multi-channel composite antenna B of 34ch is arranged inside each antenna element a of the multi-surface composite antenna A of 29ch. It was possible to realize characteristics substantially equal to the directivity characteristics in the horizontal plane of the 29-ch multi-plane synthetic antenna A shown. In addition, the effects of the antenna element a can be reduced by tilting the antenna surfaces of the antenna elements a and b constituting the two multi-plane composite antennas A and B and slightly changing the vertical directions of these antenna surfaces. The horizontal plane directivity characteristic of the multi-plane synthetic antenna B can be greatly improved by reducing this. Further, it was confirmed that even if the antenna surfaces of the antenna elements a and b were tilted as described above, the directivity characteristics in the vertical direction had almost no problem as shown in FIG.

  By the way, as described above, when the antenna elements a (b) provided in four steps up and down are respectively tilted, spatially between the antenna surfaces of the antenna elements a (b) as schematically shown in FIG. A shift in distance will occur. Accordingly, if the distance deviation is anticipated, and each antenna element a (b) is excited by giving a predetermined phase difference by adjusting the feed line length, for example, the antenna element a (b) It is possible to spatially match the phase (wavefront) of the radio waves radiated from each. As a result, it is possible to effectively combine the radio waves radiated from the respective antenna elements a (b) and increase the radio field intensity for transmission, so that the tilt described above becomes a big problem for the transmission antenna device. There is nothing.

  The present invention is not limited to the embodiment described above. Here, the UHF 29ch multi-plane synthetic antenna A and the UHF 34ch multi-plane synthetic antenna B are illustrated with respect to the space-sharing transmission antenna apparatus installed at the same height, but the transmission radio frequency may be determined according to the specifications. It is. Needless to say, the present invention can also be applied to a case where three or more polyhedral antennas are installed at the same height. The number (number) of antenna elements constituting the multi-plane composite antenna, the size and arrangement interval of each antenna element, and the like may be determined according to the specifications of the broadcasting tower or the like.

  In addition, here, the antenna elements provided in the upper and lower stages are respectively tilted at the arrangement positions. However, it is of course possible to tilt the entire antenna element while maintaining the antenna surfaces of the plurality of antenna elements provided in the upper and lower stages in a constant manner. Is possible. However, in this case, since the difference between the distance from the center of the column at the upper end and the distance from the center of the column at the lower end is increased by tilting, it is necessary to fully consider the tilt angle.

  Of course, it is possible to tilt only one antenna surface of the two multi-surface synthetic antennas A and B described above. In short, the angle difference in the vertical direction is made to the antenna surface of each antenna element in the plurality of multi-surface synthetic antennas. It is enough to have it. Furthermore, it goes without saying that the configuration and size of each antenna element can be variously modified. In addition, the present invention can be variously modified and implemented without departing from the scope of the invention.

The top view which shows schematic structure of the transmission antenna apparatus which concerns on one Embodiment of this invention. The figure which shows the cross-sectional structure of the transmitting antenna apparatus shown in FIG. The figure which shows the structural example of the antenna element used for the transmitting antenna apparatus shown in FIG. The figure which shows the directional characteristic in the horizontal surface of the antenna element shown in FIG. The figure which shows the directional characteristic in the horizontal surface of the polyhedral synthetic | combination antenna of UHF34ch in the transmission antenna apparatus shown in FIG. The figure which shows the directional characteristic in the horizontal surface of the polyhedral synthetic | combination antenna of UHF29ch in the transmitting antenna apparatus shown in FIG. The figure which shows the vertical direction directivity of the polyhedral synthetic | combination antenna of UHF34ch in the transmission antenna apparatus shown in FIG. The figure which shows the example of the excitation method with respect to the several antenna element tilted to the up-down direction.

Explanation of symbols

A, B polyhedral antenna a, b antenna element P support

Claims (5)

A transmission antenna in which a plurality of antenna units having the same number of three or more planes, each constituting a plurality of multi-surface synthetic antennas having different transmission radio frequencies, are circularly arranged at equal angular intervals in a predetermined order in a horizontal plane centered on a support column. A device,
A plurality of antenna units that constitute each of the plurality of multi-surface synthetic antennas are provided to be tilted so that the angle of the antenna surface is different in the vertical direction between the multi- surface synthetic antennas of the plurality of multi-surface synthetic antennas having different transmission radio frequencies . A transmitting antenna device characterized by the above. 2. The transmitting antenna device according to claim 1, wherein the plurality of antenna units constituting each of the plurality of multi-surface synthetic antennas are provided with the antenna surface tilted in the vertical direction at an angle determined for each transmission radio frequency. . A plurality of antenna units that constitute the plurality of multifaceted synthetic antenna respectively, in claim 1 or claim 2 in which are arranged at equal angular intervals on the circumferential surface of determined size corresponding to the transmission radio wave frequency, respectively The transmitting antenna device described. The plurality of antenna units constituting each of the plurality of multi-surface synthetic antennas are multi-staged in the vertical direction at each position determined by equiangular intervals on a circumferential surface having a diameter determined according to the transmission radio frequency. The transmission antenna device according to claim 1 , wherein the transmission antenna device is provided in the transmission antenna. Each antenna unit is configured by providing a predetermined number of double-loop antennas having an antenna length corresponding to a transmission radio frequency on a flat plate-like reflection plate with an antenna surface parallel to the main surface of the reflection plate. The transmitting antenna device according to any one of claims 1 to 4 , wherein the transmitting antenna device radiates a radio wave having a main lobe in a direction perpendicular to a main surface of the antenna.

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