JP2017184008A - Horizontal polarization non-directional antenna device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-weight and compact horizontal polarization non-directional antenna device having a wide frequency bandwidth.SOLUTION: A horizontal polarization non-directional antenna device includes first and second antenna substrates 12 having a feeding point fp, and provided with multiple antennas 11 radially from the feeding point, a power supply board 14 provided between respective antenna substrates 12 while touching both ends to the opposite plate surfaces of these antenna substrates 12, and brought into conductive connection with respective feeding points, an antenna base 10A fixed to an external support, and holding respective antenna substrates 12, at a predetermined interval, while facing each other, and a feed line foe feeding each feeding point.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a horizontal polarization omnidirectional antenna device suitable for application to, for example, a radio relay transmission device (FPU) that can be mounted on an aircraft.

  Conventionally, a slot antenna using a waveguide has been used as a transmission / reception antenna of a radio relay transmission device (FPU) mounted on an aircraft. The slot antenna based on this waveguide has a relatively simple structure and can be constructed robustly, but has a problem that the weight burden on the fuselage is large and the installation location is specified. It is narrow and has a problem that a unique waveguide structure is required for each frequency band used.

JP 2014-78805 A

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a horizontally polarized omnidirectional antenna device that is lightweight and compact and has excellent frequency band characteristics.

  The present invention relates to a horizontally polarized omnidirectional antenna device suitable for application to an FPU antenna of a television broadcast radio relay transmission device (FPU) mounted on a light aircraft such as a rotary wing aircraft or an unmanned aircraft. The first and second antenna substrates each having a feeding point and a plurality of antennas provided radially from the feeding point, and the antenna substrates between the antenna substrates with both ends in contact with opposite plate surfaces. A power supply board that is conductively connected to each of the power supply points, an antenna base that is fixed to an external support and holds the antenna boards facing each other at a predetermined interval, and a power supply that supplies power to each of the power supply points And a road.

  With this configuration, it is possible to provide an FPU antenna that is lightweight and compact and has a wide frequency bandwidth spanning a plurality of bands (for example, C band to D band (6,425 MHz to 7,125 MHz)).

  Further, in the horizontally polarized omnidirectional antenna device having the above-described configuration, the first and second antenna substrates and the power supply substrate constitute a set of antenna modules, and the antenna module includes a plurality of sets of the antenna modules. A distribution board is provided between the antenna modules and the antenna modules are stacked.

  With this configuration, it is possible to supply a horizontal FPU antenna having a plurality of antenna substrates arranged in an array in the horizontal direction.

  Further, in the horizontally polarized omnidirectional antenna device having the above-described configuration, the antenna substrate is configured so that an in-plane direction along the plate surface of the antenna substrate is different from the antenna substrates by a predetermined angle in a circumferential direction. It is characterized by having a directivity adjusting means to be held in the.

  With this configuration, it is possible to provide an omnidirectional antenna that uses a plurality of antenna substrates to reduce directional ripples in the horizontal plane.

  Further, in the horizontally polarized omnidirectional antenna device having the above configuration, the antenna includes a feed line having one end electrically connected to the feed point, an antenna element conductively connected to the other end of the feed line, and the antenna element. And a parasitic element provided so as to correspond to the above.

  With this configuration, the antenna characteristics (band, gain, etc.) can be adjusted to the characteristics required for the antenna device.

The perspective view seen from diagonally upward which shows the structure of the horizontal polarization omnidirectional antenna device which concerns on embodiment of this invention. The perspective view seen from diagonally downward which shows the structure of the horizontal polarization omnidirectional antenna apparatus which concerns on the said embodiment. The figure which shows the structure of the surface of the antenna element board | substrate which concerns on the said embodiment. The figure which shows the structure of the back surface of the antenna element board | substrate which concerns on the said embodiment. The schematic diagram which shows the example of mounting of the horizontal polarization omnidirectional antenna apparatus which concerns on the said embodiment, and a feed structure. The figure which shows the VSWR characteristic of the horizontal polarization omnidirectional antenna apparatus which concerns on the said embodiment. The figure which shows the radiation pattern of the horizontal polarization omnidirectional antenna apparatus which concerns on the said embodiment.

  Embodiments of the present invention will be described below with reference to the drawings.

  An outline of the horizontally polarized omnidirectional antenna device according to this embodiment will be described in detail. In this embodiment, the radio transmission frequency band is taken as an example of a horizontally polarized omnidirectional antenna device of a digital radio transmission equipment (FPU). This horizontally polarized omnidirectional antenna device radiates horizontally polarized waves omnidirectionally by arranging three dipole antennas on a circular substrate at intervals of 120 ° (see FIGS. 1 and 2). In addition, since a sufficient bandwidth characteristic or gain cannot be obtained with a dipole antenna alone, a parasitic element is provided in each antenna element to realize a broadband characteristic or a higher gain (see FIG. 3). Power feeding to the dipole antenna is performed by three parallel lines distributed from a feeding point provided in the center of the substrate. Further, in order to obtain a gain of 5 dBi or more in the horizontal direction, an array is formed using four antenna substrates having the same configuration. The distance between the antenna substrates is set and held by three support columns arranged at equal intervals so as to surround the substrate. The power supply to the antenna substrate is performed by a tournament method using a first distribution substrate and two power supply substrates (second distribution substrate). In the power supply structure, the connection from the connector to the second distribution board is made by a coaxial cable, and the connection between the second distribution board and the antenna board is made by a microstrip line (see FIGS. 1, 2 and 5).

  With this antenna structure, a wide-band omnidirectional antenna with a VSWR of 15% or less (see FIG. 6) and a horizontal plane directivity ripple of 2 dB or less (see FIG. 7) is realized. In addition, the antenna diameter is about 10% (50mm) smaller than the conventional product using a waveguide, the overall length is shortened by 5% (190mm), and the weight is reduced by 50% (390g) to reduce size and weight. Yes.

  The configuration of a horizontally polarized omnidirectional antenna device according to an embodiment of the present invention is shown in FIGS. 1 and 2, and the configuration of an antenna substrate that constitutes a component of this antenna device is shown in FIGS. FIG. 5 schematically shows a mounting example and a power feeding structure.

  As shown in FIGS. 1 and 2, the horizontally polarized omnidirectional antenna apparatus 10 according to the embodiment of the present invention has a feeding point fp, and a plurality of (here, three) dipole antennas 11 are connected to the feeding point fp. The first and second antenna substrates 12 and 12 having the same configuration that form a pair provided radially with respect to each other, and the antenna substrates 12 and 12 between the antenna substrates 12 and 12 that form a pair are arranged on the plate surface of the antenna substrate 12 and 12. The feeding substrate 14 provided between the feeding points fp in an orthogonal state and conductively joined to the feeding point fp and the antenna substrates 12 and 12 face each other and are held in parallel, and the feeding point fp. Are arranged on the same straight line (see reference numeral VD shown in FIG. 5) passing through the pair of antenna boards 12, 12 (here, three) support columns 16, 16,. power fp Has a connector 10C for parts connected, the three struts 16, 16, ... it is configured by including an antenna base 10A which is erected at equal intervals around the center of the connector 10C. On the antenna support surface of the antenna base 10A, a disk-shaped electromagnetic wave absorber sheet 18 of a size determined from the measurement results such as directivity, gain, and VSWR related to the antenna characteristics is attached. A plurality of bolt through holes H are provided for installing the horizontally polarized omnidirectional antenna device 10 on the bottom of the aircraft body.

  As shown in FIGS. 3 and 4, the circular antenna substrate 12 has three first mounting holes through which the threaded portion of the support column 16 for fixing the substrate to the antenna base 10 </ b> A penetrates at the peripheral portion of the plate surface. ha and three second mounting holes hb are alternately provided at equal intervals on the same circumference. The three first mounting holes ha and the three second mounting holes hb are oriented in the in-plane direction along the plate surface of the dipole antenna 11 with the feeding point fp between the paired antenna substrates 12 and 12 as the center. The directivity adjusting means is configured to be held by the support columns 16, 16,.

  Further, as shown in FIGS. 3 and 4, the antenna substrate 12 has an antenna pattern (dipole antenna) constituting a dipole antenna having the same shape with the center of the plate surface as the feeding point fp on each of the front surface 12a and the back surface 12b. A pattern made of a conductive material (for example, copper foil) is provided, and three horizontally polarized dipole antennas 11 are formed by the antenna patterns on both the front and back plate surfaces 12a and 12b and the parasitic element pattern printed on the front surface 12a. , 11, 11 are formed. An antenna pattern on the power feeding side is formed on the front surface 12a of the antenna substrate 12, and an antenna pattern on the ground (GND) side is formed on the back surface 12b.

  This dipole antenna 11 has an antenna substrate 12 having an antenna pattern of the same shape having a feed line 11a radially extending from a feed point fp of the antenna and an antenna element 11b bent and extended from the feed line 11a. Are formed in line symmetry (see reference numeral 11b indicated by a wavy line in FIG. 3) in which the feeder line 11a is superimposed on both the plate surfaces 12a and 12b. The feeding lines 11a of the both plate surfaces 12a and 12b form a parallel line having a constant impedance. In addition, a parasitic element pattern constituting the parasitic element 11c is formed on the surface 12a of the antenna substrate 12 in parallel with the antenna element 11b with a gap in the horizontal direction of the antenna element 11b. The parasitic element 11c constitutes a waveguide element and adjusts the directivity of horizontal polarization. A feeding end (described later) of a feeding board 14 provided at a central portion of the antenna board 12 where the feeding lines 11a of the three horizontally polarized dipole antennas 11, 11, 11 are gathered at right angles to the plate surface of the board. A through hole to be soldered is provided at the end of the microstrip line, and constitutes a feeding point fp.

  Further, the antenna substrate 12 has a plurality of (three in this case) cable through holes hc through which a later-described feeding coaxial cable 15 passes through the plate surface between the feed lines 11a (the plate surface near the feed point fp). It has been drilled. By using this cable through hole hc, wiring of the coaxial cable 15 between the connector 10C and the distribution board 13 and between the distribution board 13 and the power supply board 14 is performed, so that the four antenna boards 12, 12, ..., a low-loss power supply circuit with the shortest distribution power supply path is constructed.

  The antenna substrates 12 and 12 forming the above-mentioned pair are in a state where the back surfaces 12b face each other, and one antenna substrate 12 uses the first mounting hole ha and the other antenna substrate 12 uses the second mounting hole hb. It is hold | maintained at three support | pillars 16, 16, ..., respectively. In this way, the antenna substrates 12 and 12 that make a pair are held in the support columns 16, 16,... With different mounting holes, so that the in-plane direction of the dipole antennas 11, 11,. The antenna substrates 12 and 12 that make a pair can be held at 60 degrees different in the circumferential direction around the feeding point fp, thereby reducing the directional ripple in the horizontal plane and eliminating horizontal polarization. Directivity is realized. Further, the antenna substrate 12, 12,... Is strong against external stress as a substrate holding structure in which the antenna substrates 12, 12,... Are uniformly held by three support columns 16, 16,. Realizes a robust antenna structure.

  In this embodiment, a set of antenna modules DA is constituted by the first and second antenna substrates 12 and 12, the power supply substrate 14, the support column 16 and the holder 17 attached to the support column 16. A plurality of (in this case, two) DAs are provided, and a power supply cable 15 connected to the connector 10C and a distribution board 13 connected to the power supply cable 15 are provided. , DA is stacked on the same straight line with the distribution board 13 interposed therebetween. The two sets of antenna modules DA and DA constitute an array antenna in which four antenna substrates 12, 12,... Are arranged on one axis in the direction along the same straight line (in the vertical plane). The antenna modules DA and DA stacked on one axis are accommodated in a cylindrical radome (cover) 10B and fixed to the antenna base 10A to constitute the horizontally polarized omnidirectional antenna device 10. The horizontally polarized omnidirectional antenna device 10 is mounted in a state where the antenna base 10A is bolted to the outer bottom of the aircraft body and the tip of the radome 10B is directed downward and exposed to the outside of the aircraft as shown in FIG. It is done.

  The horizontal polarization omnidirectional antenna device 10 supplies power to four antenna substrates 12, 12,... Using the distribution substrate 13 as a first distribution substrate and the two power supply substrates 14, 14 as second distribution substrates. .

  The distribution board 13 serving as the first distribution board has three distribution terminals T1, T2, T2 to which the coaxial cable 15 is connected, and the distribution terminal T1 connected to the connector 10C via the coaxial cable 15 is used as an input end. Distribution power is supplied to the two distribution terminals T2 and T2 via the coaxial cable 15. At this time, the coaxial cable 15 is wired at the shortest distance through the cable through hole hc provided near the center of the antenna substrate 12.

  The rectangular power supply substrate 14 serving as the second distribution substrate has a microstrip line (hereinafter simply referred to as a strip line) in which the power supply pattern pa is disposed on one surface and the ground pattern pb is disposed on the other surface. Are soldered to the feeding points fp of the antenna substrates 12 and 12 in pairs. This strip line has a distribution terminal T3 serving as a power distribution point in the middle of the strip line divided into two, and performs distributed power supply to each of the power supply points fp and fp via the strip line.

  This power supply circuit is schematically shown in FIG. As shown in FIG. 5, a coaxial cable 15 is used in the power supply path from the connector 10C to the distribution terminal T3 (10C-T1-T2-T3), and the antenna substrate 12 is paired with the distribution terminal T3 of the power supply substrate 14. , 12 is used as a feeding path between the feeding point fp and a half of the strip line formed on the feeding substrate 14, and the end of the strip line is provided at the center of the antenna substrate 12. The connector 10C and the two antenna modules DA and DA, the power supply boards 14 and 14 provided on the two antenna modules DA and DA, and the power supply points fp and fp of the antenna boards 12 and 12 ,... Are arranged on a single axis (VD) corresponding to the same straight line, and a compact cylindrical horizontally polarized omnidirectional antenna device 10 having low air resistance is realized and provided. Kill.

  FIG. 6 shows the VSWR (voltage standing wave ratio) characteristics of the horizontally polarized omnidirectional antenna device 10 actually manufactured by the configuration of the above embodiment. By adjusting the parasitic element 11c and the feeding circuit described above, the VSWR was 2 or less within a range of 15%. The radiation patterns of f1 and f2 in the VSWR of this antenna device are shown in FIGS. 7 (a) and 7 (b). As is apparent from the measurement results, the horizontal polarization omnidirectional antenna 10 in which the horizontal plane directivity ripple is 2 dB or less and the horizontal polarization directivity is greatly improved is realized.

  As shown in the above embodiment, the antenna substrate has first and second antenna substrates each having a feeding point and a plurality of dipole antennas provided radially around the feeding point, and between the antenna substrates. An antenna base provided between the feeding points in a state orthogonal to the plate surface and electrically connected to the feeding point, an antenna base having a connector for external connection for feeding power to the feeding point, and the antenna The base is provided with substrate holding means for holding the antenna substrates facing each other in parallel and arranging the feeding point on the same straight line penetrating the antenna substrate. To D band (6,425 MHz to 7,125 MHz), a horizontally polarized omnidirectional antenna device having a wide frequency bandwidth can be provided.

  In the horizontally polarized omnidirectional antenna device having the above-described configuration, the first and second antenna substrates and the feeding substrate constitute a set of antenna modules, and a plurality of antenna modules are provided, and the connector A power supply cable connected to the power supply cable and a distribution board connected to the power supply cable, and the plurality of sets of antenna modules are stacked on the same straight line with the distribution board interposed therebetween. An antenna for FPU having a wider bandwidth in the horizontal direction, in which a single antenna substrate is arrayed, can be provided.

  Further, in the horizontally polarized omnidirectional antenna device having the above configuration, the dipole antenna has the same shape having a feed line extending radially from the feed point and an antenna element bent and extended from the feed line A pattern made of a conductive material is formed symmetrically with the feeding line superimposed on both plate surfaces of the antenna substrate, and a conductive material constituting a parasitic element corresponding to the antenna element on one plate surface By arranging such patterns in parallel, it is possible to provide a light and compact omnidirectional dipole antenna device in a horizontal plane in which all the antenna boards to be used have the same configuration and the number of parts is reduced.

  Further, in the horizontally polarized omnidirectional antenna device having the above configuration, the antenna substrate is oriented in an in-plane direction along the plate surface of the dipole antenna in a circumferential direction centering on the feeding point between the antenna substrates. With the configuration having the directivity adjusting means that is held at the support column with a predetermined angle difference, an omnidirectional dipole antenna with reduced horizontal plane directivity ripple using a plurality of antenna substrates having the same configuration can be provided.

  In the horizontal polarization omnidirectional antenna device having the above configuration, the power supply board has a microstrip line in which a power supply pattern is arranged on one surface and a ground pattern is arranged on the other surface, and is provided in an intermediate portion of the microstrip line. By having a distribution board that has a distribution feed point and feeds power to the feed point through one of the two half-strip microstrip lines, a simple feed structure and low loss can be achieved with respect to the antenna board that forms a pair. It is possible to provide a horizontally polarized omnidirectional antenna apparatus having an economically advantageous configuration that enables distributed feeding.

  Further, in the horizontally polarized omnidirectional antenna device having the above configuration, the antenna substrate has a through-hole soldered to an end of the microstrip line, and the solder joint is used as the feeding point. With a configuration in which three dipole antennas are provided on the antenna substrate at 120 ° intervals on the antenna substrate, it is compact and robust with a cylindrical appearance, and non-directional horizontal polarization across multiple bands. A horizontally polarized omnidirectional antenna device that can be radiated can be provided.

  Further, in the horizontally polarized omnidirectional antenna device having the above-described configuration, the antenna substrate passes through the substrate at equal intervals in the circumferential direction at a plurality of attachments constituting the directivity adjusting means. The substrate holding means has a plurality of support posts that are inserted through the mounting holes and fix the antenna substrate to the antenna base, so that each antenna substrate is surrounded by a hole. A horizontally polarized omnidirectional antenna device that has a substrate holding structure that is uniformly held by a plurality of support columns and that realizes a robust antenna structure resistant to external stress can be provided.

  As described above in detail, according to the embodiment of the present invention, a high-performance horizontally polarized omnidirectional antenna apparatus that is lightweight and compact and excellent in frequency band characteristics can be provided.

  In addition, the above-described embodiment has a configuration suitable for application to a transmission / reception antenna of an FPU mounted on a flying object such as an aircraft. For example, a cylindrical dome is modified by modifying the outer casing structure or the same as the embodiment. As a structure, it can be applied to a moving body such as a vehicle or a ship or a fixed station on the ground.

  In the above-described embodiment, the antenna structure has two antenna modules DA mounted. However, the present invention is not limited to this, and for example, an antenna structure in which four antenna modules DA are mounted may be used. In addition, the substrate shape and pattern shape of the antenna substrate 12 are not limited to the shapes shown in the drawings, and for example, a substrate structure in which the substrate shape is a polygon and the antenna element pattern shape is an arc shape or the elements have different lengths. May be. Various modifications and changes can be made to the arrangement, connection structure, power feeding structure, support structure and the like of the substrates constituting the antenna module DA without departing from the gist of the present invention.

  The present invention has been described above by taking the embodiment as an example. However, various modifications and changes can be made to the configuration of each element without departing from the gist of the present invention. Hereinafter, modifications will be described.

  Modification 1: In the above embodiment, a dipole antenna is used as an antenna. However, any antenna that is suitable for being formed on a substrate, such as a circular or polygonal patch antenna, may be used. May be used. With this configuration, a horizontally polarized omnidirectional antenna device in which an antenna suitable for a required band (including bands other than C and D bands) and gain can be provided.

  Modification 2: In the above embodiment, three antennas are arranged on the substrate at intervals of 120 °, but four or more antennas may be arranged at narrower intervals (for example, four antennas are arranged at intervals of 90 °). Good. With this configuration, even when a single antenna having a narrow beam width (sharp directivity) is used, an omnidirectional horizontally polarized omnidirectional antenna device as a whole can be provided.

  Modification 3: In the above-described embodiment, a plurality of antennas having the same shape are formed on the substrate. However, the antennas may not have the same shape (the shape includes a size, the same applies hereinafter). For example, two types of antennas may be alternately formed on the substrate, and antennas having different band characteristics may be combined and arranged. With this configuration, it is possible to provide a horizontally polarized omnidirectional antenna device having a wider bandwidth than the case where the antennas have the same shape.

  Modification 4: In the above embodiment, a plurality of antennas are arranged at equiangular intervals on the substrate, but a plurality of antennas may be arranged at unequal angular intervals. For example, by using multiple antennas with different directivities and arranging the antennas at angular intervals according to the beam width, a horizontally polarized omnidirectional antenna device that exhibits horizontal polarization omnidirectionality as a whole antenna device is provided. it can.

  Modification 5: In the above embodiment, power from the outside of the antenna device is supplied to the power feeding point via the connector for external connection, but other power feeding methods may be used. For example, by using a structure in which a coaxial cable is directly led out of the antenna device and power is supplied from the outside, a connector is not required and the weight can be reduced, or the antenna device (in the dome) By adopting a structure in which a power supply is provided, a horizontally polarized omnidirectional antenna device that does not require an external power supply can be provided.

  Modification 6: In the above embodiment, the antenna substrates are held in parallel so as to face each other. However, the antenna substrates may not be parallel as long as the antenna substrates face each other. For example, when the antenna substrates are parallel to each other, the angle may be held within a range of 0 ° to 45 ° when the angle is 0 °. In short, it is only necessary to achieve horizontal plane omnidirectionality in the entire antenna device, and thereby a horizontally polarized omnidirectional antenna device with a high degree of freedom of incorporation can be provided.

  Modification 7: In the above-described embodiment, the antenna module is configured to be stacked on the same straight line with a distribution board interposed therebetween, but other configurations may be used. In the above embodiment, the antenna module is housed in a cylindrical radome (cover). For example, when the antenna module is housed in a cover that is bent or refracted in the middle, the antenna module is placed on the same straight line. The horizontal polarization omnidirectional antenna apparatus having a configuration with a high degree of freedom in shape according to the installation location can be provided.

  Modification 8: In the above embodiment, the feeding point is provided at the center of the antenna substrate. However, if the antenna device as a whole has omnidirectionality, the feeding point may be provided at a location other than the center of the antenna substrate. For example, when a plurality of antennas having different sizes are provided on the antenna substrate, the feeding point may be shifted from the center of the antenna substrate. As a result, it is possible to provide a horizontally polarized omnidirectional antenna device having a high degree of freedom by combining antennas of different types and sizes.

  DESCRIPTION OF SYMBOLS 10 ... Horizontally polarized omnidirectional antenna, 10A ... Antenna base, 10B ... Radome (cover), 10C ... Connector, 11 ... Dipole antenna, fp ... Feed point, 11a ... Feed line, 11b ... Antenna element, 11c ... Parasitic Element 12 ... Antenna board 13 ... Distribution board (first distribution board) 14 ... Power feeding board (second distribution board) T1, T2, T3 ... Distribution terminal, 15 ... Coaxial cable, 16 ... Column, 17 ... Holder , DA ... Antenna module.

Claims (4)

First and second antenna substrates each having a feeding point and provided with a plurality of antennas radially from the feeding point;
Power feeding boards that are provided between the antenna boards in contact with opposite ends of the antenna boards facing each other, and are conductively connected to the feeding points,
An antenna base fixed to an external support and holding the antenna substrates facing each other at a predetermined interval;
A power supply path for supplying power to each of the power supply points;
A horizontally polarized omnidirectional antenna device. The first and second antenna substrates and the power supply substrate constitute a set of antenna modules, and a plurality of antenna modules are provided.
The horizontally polarized wave omnidirectional antenna device according to claim 1, wherein a distribution board is provided between the antenna modules to stack the antenna modules.   The antenna board has a directivity adjusting means for holding the antenna base in an in-plane direction along a plate surface of the antenna board by making the antenna boards different from each other by a predetermined angle in a circumferential direction. The horizontally polarized omnidirectional antenna device according to claim 1 or 2.   The antenna includes a feed line having one end conductively connected to the feed point, an antenna element conductively connected to the other end of the feed line, and a parasitic element provided in correspondence with the antenna element. The horizontally polarized omnidirectional antenna device according to any one of claims 1 to 3, wherein:

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