JP2015050669A - Antenna and sector antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna, and the like, that can be made compact while suppressing the effects of transmission and reception, of radio waves in one frequency band, on the directivity, and the like, in the transmission and reception of radio waves in other frequency band, in the transmission and reception of radio waves in a plurality of frequency bands.SOLUTION: An antenna unit 110 includes a low frequency antenna provided on the surface of a low frequency reflector 150 and transmitting and receiving the radio waves of low frequency band, and a high frequency antenna for transmitting and receiving the radio waves of high frequency band. Conductors are provided, respectively, from two elements of the high frequency antenna toward the reflector, and the interval in a direction parallel with the low frequency reflector 150 is wider on the side closer to the low frequency reflector 150 compared with the interval on the remote side.

Description

  The present invention relates to an antenna and a sector antenna.

  As a mobile communication base station antenna (base station antenna), a plurality of sector antennas that transmit and receive radio waves for each sector set corresponding to the direction of transmitting and receiving radio waves are used in combination. As the sector antenna, an array antenna in which antenna elements such as a dipole antenna are arranged in an array is used.

  Patent Document 1 discloses a multi-frequency shared antenna including a reflector and a log-periodic dipole antenna having a plurality of dipole elements that are arranged at intervals from the reflector and radiate radio waves of different frequencies. In the log periodic dipole antenna, the distance between the dipole element radiating the highest frequency radio wave and the reflector is the smallest, and the distance between the dipole element radiating the lowest frequency radio wave and the reflector is the largest. As described above, a multi-frequency shared antenna disposed to be inclined with respect to the reflector is described.

  Patent Document 2 discloses a frequency sharing polarization antenna apparatus in which individual antenna units applied to two different polarizations are provided for each of a plurality of frequency bands, and a folded dipole antenna as an antenna element of each antenna unit. A frequency sharing polarization antenna device using an element is described.

JP 2006-229337 A JP 2013-38636 A

By the way, an antenna may be required to be able to transmit and receive radio waves in different frequency bands. At that time, it is required that transmission and reception of radio waves in the first frequency band have little influence on directivity in other frequency bands.
An object of the present invention is to provide an antenna or the like that can be miniaturized while suppressing the influence on directivity in other frequency bands due to transmission / reception of radio waves in a first frequency band in transmission / reception of radio waves in a plurality of frequency bands. It is in.

  For this purpose, an antenna to which the present invention is applied includes a reflector, a first dipole antenna that is provided at a predetermined first distance from the reflector, and that transmits and receives radio waves in the first frequency band. The second side of the reflecting plate is provided at a predetermined second distance from the reflecting plate on the side where the first dipole antenna is provided, and transmits and receives radio waves in a second frequency band higher than the first frequency band. The dipole antenna and the two dipole antennas that constitute the second dipole antenna and transmit and receive radio waves in the second frequency band are provided from the respective element portions toward the reflector, and the interval in the direction parallel to the reflector is The side closer to is provided with a wider conductor than the far side.

Then, on the side of the reflector on which the first dipole antenna is provided, a third distance is provided at a predetermined third distance from the reflector, and transmits and receives polarized radio waves intersecting the first dipole antenna. On the side where the first dipole antenna and the first dipole antenna of the reflector are provided, the first dipole antenna is provided at a predetermined fourth distance from the reflector, and transmits and receives polarized radio waves intersecting the second dipole antenna. And at least one of the four dipole antennas.
According to this configuration, polarization can be shared compared to the case without this configuration.

Furthermore, it can be characterized by further including a parasitic element.
According to this configuration, it is possible to more easily control the beam width, the return loss, and the like as compared with the case where the antenna does not include a parasitic element.

From another point of view, a sector antenna to which the present invention is applied is provided with a reflector and a first dipole that is provided at a predetermined first distance from the reflector and transmits and receives radio waves in the first frequency band. On the side where the antenna and the first dipole antenna of the reflector are provided, the antenna is provided at a predetermined second distance from the reflector and transmits and receives radio waves in a second frequency band higher than the first frequency band. The second dipole antenna and the two element portions that constitute the second dipole antenna and transmit / receive radio waves in the second frequency band are provided toward the reflecting plate from each other, and an interval in a direction parallel to the reflecting plate is provided. An array antenna in which a plurality of antennas each having a conductor wider on the side closer to the reflector than that on the far side is arranged, and a radome that houses the array antenna are provided.
According to this configuration, the sector antenna can be made smaller than in the case without this configuration.

  ADVANTAGE OF THE INVENTION According to this invention, in the antenna which transmits / receives the electromagnetic wave of several frequency bands, it can reduce in size, suppressing the influence with respect to the directivity in the other frequency band by transmission / reception of the electromagnetic wave of one frequency band.

It is a figure which shows an example of the whole structure of the base station antenna for mobile communication with which 1st Embodiment is applied. It is a figure which shows an example of a structure of the sector antenna to which 1st Embodiment is applied. It is a figure explaining an example of the low frequency vertical polarization antenna and high frequency vertical polarization antenna to which 1st Embodiment is applied. 2A is a diagram of a low-frequency vertical polarization antenna viewed from the right in the horizontal direction in FIG. 2, and FIG. 2B is a diagram of a high-frequency vertical polarization antenna viewed from the right in the horizontal direction in FIG. It is a figure explaining the modification of the sector antenna to which 1st Embodiment is applied. It is a figure explaining an example of the structure of the sector antenna to which 2nd Embodiment is applied. It is a figure explaining the modification of the sector antenna to which 2nd Embodiment is applied. It is a figure explaining an example of the directivity in the horizontal surface with respect to the vertically polarized wave of the low frequency band of the array antenna to which 2nd Embodiment is applied. (A) is a figure explaining an array antenna, (b) is a figure which shows the directivity in the horizontal surface with respect to the vertical polarization of the low frequency band of the array antenna shown to (a). It is a figure explaining an example of the directivity in the horizontal surface with respect to the vertically polarized wave of the low frequency band of the array antenna which does not apply 2nd Embodiment. (A) is a figure explaining an array antenna, (b) is a figure which shows the directivity in the horizontal surface with respect to the vertical polarization of the low frequency band of the array antenna shown to (a).

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
[First Embodiment]
<Base station antenna 1>
FIG. 1 is a diagram illustrating an example of an overall configuration of a base station antenna 1 for mobile communication to which the first embodiment is applied. FIG. 1A is a perspective view of the base station antenna 1, and FIG. 1B is a diagram illustrating an installation example of the base station antenna 1.
As shown in FIG. 1A, the base station antenna 1 includes, for example, three sector antennas 10-1 to 10-3 held in a steel tower 20. Then, as shown in FIG. 1B, the base station antenna 1 transmits and receives radio waves (beams) in the cell 2. That is, the cell 2 is a range where radio waves transmitted by the base station antenna 1 reach and a range where the base station antenna 1 receives radio waves.
Each of the sector antennas 10-1 to 10-3 has a cylindrical shape (for example, a radome 500 in FIG. 2 to be described later), and the central axis of the cylinder is provided perpendicularly (vertically) to the ground. .

As shown in FIG. 1B, the cell 2 includes a plurality of sectors 3-1 to 3-3 that are divided by angles in a horizontal plane. Each of the sectors 3-1 to 3-3 is provided corresponding to the three sector antennas 10-1 to 10-3 of the base station antenna 1. That is, when the sector antennas 10-1 to 10-3 output radio waves, the direction of the main lobe 11 where the electric field of the radio waves output from the sector antennas 10-1 to 10-3 is large corresponds to the corresponding sector 3-1. It is suitable for ~ 3-3.
Here, when the sector antennas 10-1 to 10-3 are not distinguished from each other, they are represented as sector antennas 10. In addition, when the sectors 3-1 to 3-3 are not distinguished from each other, they are represented as sector 3.

  The base station antenna 1 shown as an example in FIG. 1 includes three sector antennas 10-1 to 10-3 and sectors 3-1 to 3-3 corresponding thereto. However, the number of sector antennas 10 and sector 3 may be a predetermined number less than or greater than 3. In FIG. 1A, the sector 3 is configured by dividing the cell 2 into three equal parts (center angle 120 °). However, the sector 3 may not be equally divided, and any one sector 3 may be the other. The sector 3 may be wider or narrower than the sector 3.

Each sector antenna 10 transmits a transmission signal to an antenna unit included in the sector antenna 10 (refer to antenna units 110-1 to 110-3 in FIG. 2 to be described later. When not distinguished from each other, they are referred to as antenna units 110). And transmission / reception cables 31 and 32 for transmitting and receiving received signals.
Here, it is assumed that the sector antenna 10 is frequency sharing capable of transmitting and receiving signals having two different frequency bands, and the transmission / reception cable 31 transmits signals in a lower frequency band (a low frequency band as an example of the first frequency band). Correspondingly, the transmission / reception cable 32 corresponds to a signal in a higher frequency band (a high frequency band as an example of the second frequency band).
The transmission / reception cables 31 and 32 are connected to a transmission / reception unit (not shown) that transmits and receives transmission signals and reception signals provided in a base station (not shown). The transmission / reception cables 31 and 32 are, for example, coaxial cables.

  In the following description, it is assumed that the base station antenna 1 mainly transmits radio waves, but the base station antenna 1 can receive radio waves due to the reversibility of the antenna. When receiving radio waves, for example, the signal flow may be reversed with the transmission signal as the reception signal.

  The sector antenna 10 may also include a phase shifter for making the phases of transmission signals transmitted to each of the plurality of antenna units 110 included in the sector antenna 10 different from each other. By setting the phases of the transmission signals supplied to the plurality of antenna units 110 to be different, the radiation angle of the radio wave is inclined from the horizontal plane to the ground (by beam tilt) so that the radio wave does not reach the outside of the cell 2. it can. Note that two phase shifters may be provided for each of the two frequency signals.

<Sector antenna 10, array antenna 100>
FIG. 2 is a diagram illustrating an example of the configuration of the sector antenna 10 to which the first exemplary embodiment is applied. In FIG. 2, the sector antenna 10 is placed sideways and is shown in a perspective view seen from an oblique direction.
The sector antenna 10 includes an array antenna 100 including antenna units 110-1, 110-2, and 110-3 arranged in a vertical direction, and a radome 500 that is housed so as to wrap the array antenna 100.
In FIG. 2, the radome 500 is indicated by a broken line so that the array antenna 100 provided inside the radome 500 can be seen.
Antenna unit 110-1, 110-2, 110-3 are arranged at intervals _{P L} which is predetermined in the vertical direction.
The radome 500 is cylindrical, for example, and includes a wall portion 501, a lid portion 502, and a bottom portion 503, and the array antenna 100 is housed inside the wall portion 501, the lid portion 502, and the bottom portion 503.

<Antenna unit 110>
The antenna unit 110 includes two low-frequency vertical polarization antennas 120a and 120b that transmit and receive vertical polarization in a low frequency band, and two high-frequency vertical polarization antennas 130a and 130b that transmit and receive vertical polarization in a high frequency band. And. The terms “low frequency” and “high frequency” are used to distinguish two types of antennas.

The low-frequency vertical polarization antennas 120a and 120b are provided on the surface side of the low-frequency reflection plate 150, which is a reflection plate set to transmit and receive low-frequency vertically polarized waves. The low frequency reflector 150 is an example of a reflector.
In FIG. 2, the low-frequency reflector 150 is continuous in a plurality of antenna units 110 (antenna units 110-1, 110-2, 110-3 in FIG. 2). Here, as shown in FIG. 2, it is assumed that the low-frequency reflector 150 is provided for each antenna unit 110 even if it is continuous between the plurality of antenna units 110.
The low-frequency reflector 150 is a rectangular plate-like member whose vertical direction is longer than the horizontal direction in a state where it is continuous between the antenna units 110, and is made of a conductive material such as aluminum, aluminum alloy, or copper. It is composed of materials.

The high frequency vertical polarization antennas 130a and 130b are provided on the surface of the high frequency reflection plate 160 (low frequency reflection plate) which is a reflection plate provided on the surface side of the low frequency reflection plate 150 and set to transmit / receive vertical polarization in a high frequency band. It is provided on the side farther from 150). Vertical polarization is polarization in which the direction of vibration of the electric field is perpendicular to the ground, and horizontal polarization is polarization in which the direction of vibration of the electric field is horizontal to the ground.
In FIG. 2, the high-frequency reflector 160 is provided for each antenna unit 110 in the center in the horizontal direction (width direction) of the low-frequency reflector 150. The high-frequency reflection plate 160 is also a plate-like member and is made of a conductive material such as aluminum, aluminum alloy, or copper.
Note that the low frequency reflector 150 may also serve as the high frequency reflector 160. That is, the high frequency reflector 160 may not be provided.

The low frequency vertically polarized antennas 120a and 120b are provided so as to sandwich the high frequency reflector 160 at both ends in the width direction (horizontal direction) of the high frequency reflector 160, respectively.
On the other hand, the high-frequency vertically polarized antennas 130a and 130b are arranged in the vertical direction on the surface of the high-frequency reflector 160 (surface far from the low-frequency reflector 150).
Since the low-frequency vertical polarization antennas 120a and 120b have the same configuration, they are denoted as the low-frequency vertical polarization antenna 120 when they are not distinguished from each other. Similarly, the configuration of the high-frequency vertical polarization antennas 130a and 130b is the same, and therefore, when not distinguished from each other, the high-frequency vertical polarization antennas 130a and 130b are labeled as the high-frequency vertical polarization antenna 130.

In the vertical direction of the array antenna 100, the low frequency vertically polarized antenna 120 are arranged at intervals P _L of the antenna unit 110 is arranged. This interval P _L is set with characteristics required for the sector antenna 10 in transmission / reception of radio waves in the low frequency band.
Further, in the vertical direction of the array antenna 100, radio-frequency vertically polarized antenna 130 are arranged at intervals _{P H.} This interval P _H is set with characteristics required for the sector antenna 10 in transmission / reception of radio waves in a high frequency band.
Here, the description will be made assuming that the interval P _L is twice the interval P _H. The interval P _L may be less than twice the interval P _H or may be more than twice.

  The low-frequency vertical polarization antenna 120 and the high-frequency vertical polarization antenna 130 are arranged in the vertical direction, and the low-frequency vertical polarization antenna 120 and the high-frequency vertical polarization antenna 130 intersect in the vertical direction (oblique direction). Thus, the antenna unit 110, the array antenna 100, and the sector antenna 10 for frequency sharing can be made compact.

The low frequency reflection plate 150 is a flat plate in FIG. 2, but both ends in the horizontal direction may be bent to the front side or the back side.
Further, although the high frequency reflector 160 is provided for each antenna unit 110 in FIG. 2, the high frequency reflector 160 may be continuous between the plurality of antenna units 110, similarly to the low frequency reflector 150. Further, the high-frequency reflector 160 is a flat plate like the low-frequency reflector 150, but both ends in the horizontal direction may be bent to the front side or the back side. Further, plate-like members made of another conductive material may be installed along the vertical direction at both ends in the horizontal direction.

The low-frequency vertically polarized antenna 120 is arranged so that two element parts 121 and 122 (see FIG. 3 described later) constituting a dipole antenna are arranged in a straight line in the vertical direction. The conductors 123 and 124 (see FIG. 3 described later) provided from the element portions 121 and 122 toward the reflecting plate are provided vertically toward the low-frequency reflecting plate 150.
The high-frequency vertically polarized antenna 130 is configured so that two element portions 131 and 132 (see FIG. 3 to be described later) constituting the dipole antenna are arranged in a straight line in the vertical direction like the low-frequency vertically polarized antenna 120. Is arranged. Unlike the low-frequency vertically polarized antenna 120, the conductors 133 and 134 (see FIG. 3 to be described later) provided from the element portions 131 and 132 toward the reflector are separated from each other as they approach the high-frequency reflector 160. It is provided toward the high-frequency reflector 160 so as to progress.

The conductors 123 and 124 may be connected to the low frequency reflection plate 150 or the high frequency reflection plate 160.
In addition, the conductors 133 and 134 may be connected to the high frequency reflection plate 160.
Further, the high frequency reflector 160 may be connected (fixed) to the low frequency reflector 150.

<Low Frequency Vertical Polarized Antenna 120 and High Frequency Vertical Polarized Antenna 130>
FIG. 3 is a diagram illustrating an example of the low-frequency vertical polarization antenna 120 and the high-frequency vertical polarization antenna 130 to which the first embodiment is applied. 3A is a view of the low-frequency vertically polarized antenna 120 viewed from the right in the horizontal direction in FIG. 2, and FIG. 3B is a view of the high-frequency vertically polarized antenna 130 viewed from the right in the horizontal direction in FIG. It is.
The low-frequency vertical polarization antenna 120 in FIG. 3A may be any of the low-frequency vertical polarization antennas 120a and 120b. As mentioned above, these are isomorphic. Similarly, the high-frequency vertically polarized antenna 130 in FIG. 3B may be any of the high-frequency vertically polarized antennas 130a and 130b. As mentioned above, these are isomorphic.

In the low-frequency vertical polarization antenna 120 and the high-frequency vertical polarization antenna 130, the portions excluding the low-frequency reflection plate 150 and the high-frequency reflection plate 160 are conductive surfaces provided on the front and back of a dielectric substrate made of a dielectric material as an example. It is assumed that it is composed of a conductor pattern made of a conductive material. For example, it is assumed that a conductor pattern is formed on a dielectric substrate such as glass epoxy which is a dielectric material by a metal foil such as copper which is a conductive material.
In FIGS. 3A and 3B, a portion indicated by a halftone dot is a conductor pattern made of a conductive material.
In FIG. 2 (FIGS. 4 to 6, FIG. 7A, FIG. 8A described later), only the conductor pattern is shown.

The low frequency vertically polarized antenna 120 will be described with reference to FIG. The low-frequency vertically polarized antenna 120 is formed of a rectangular conductor pattern formed on the surface of the dielectric substrate 141, and is an example of a first dipole antenna provided so that its longitudinal direction is aligned on a straight line. Element portions 121 and 122 are provided. The element parts 121 and 122 constitute a dipole antenna.
The low-frequency vertically polarized antenna 120 includes a conductor pattern provided on the surface of the dielectric substrate 141, and one end portion of each conductor 123 is connected to the opposing portion of the element portions 121 and 122. , 124 are provided.
The other end of each of the conductors 123 and 124 extends vertically toward the low-frequency reflector 150 and penetrates the low-frequency reflector 150 together with the dielectric substrate 141 and protrudes from the back surface of the low-frequency reflector 150. ing.
That is, the element part 121 and the conductor 123 are constituted by a continuous conductor pattern, and the element part 122 and the conductor 124 are constituted by a continuous conductor pattern.
The conductors 123 and 124 and the dielectric substrate 141 do not have to penetrate the low-frequency reflector 150.

The other ends of the conductors 123 and 124 are connected to a feeder line (not shown) on the back side of the low-frequency reflector 150. Note that the other ends of the conductors 123 and 124 may be connected to each other in the vicinity of the low-frequency reflector 150.
Although not shown, the dielectric substrate 141 and the conductors 123 and 124 are fixed by a dielectric (electrical insulator) embedded in an opening provided in the low-frequency reflector 150, and the conductors 123 and 124 and the low-frequency reflector are 150 does not contact.
Note that the dielectric substrate 141 and the conductors 123 and 124 may be in contact with the low-frequency reflector 150.

  Although not shown here, a conductor pattern for supplying a low-frequency band signal to the low-frequency vertically polarized antenna 120 is provided on the back surface of the dielectric substrate 141. This conductor pattern, together with the conductors 123 and 124, constitutes a microstrip line as well as a balance-unbalance converter.

Between the longitudinal direction of the both outer ends of the element portions 121 and 122 are set to a length _{W L.} The height from the surface of the low-frequency reflector 150 to the center of the element portions 121 and 122 in the short direction is set to a height _HL as an example of the first distance.

Next, the high-frequency vertically polarized antenna 130 will be described with reference to FIG. The high-frequency vertically polarized antenna 130 is formed of a rectangular conductor pattern formed on the surface of the dielectric substrate 142, and is an element as an example of a second dipole antenna provided so that its longitudinal direction is aligned on a straight line. Parts 131 and 132 are provided. The element parts 131 and 132 constitute a dipole antenna.
The high-frequency vertically polarized antenna 130 is composed of a conductor pattern provided on the surface of the dielectric substrate 142, and one end portion of each of the conductors 133 and 132 is connected to the opposing portion of the element portions 131 and 132. 134 is provided.
The other end portions of the conductors 133 and 134 extend toward the high-frequency reflection plate 160 so that the distances are separated from each other as they approach the high-frequency reflection plate 160. The other end portions of the conductors 133 and 134 penetrate the high-frequency reflection plate 160 together with the dielectric substrate 142 and protrude from the back surface of the high-frequency reflection plate 160.
That is, the element part 131 and the conductor 133 are constituted by a continuous conductor pattern, and the element part 132 and the conductor 134 are constituted by a continuous conductor pattern.

The other ends of the conductors 133 and 134 are connected to a feeder line (not shown) on the back side of the high-frequency reflector 160.
Although not shown, the dielectric substrate 142 and the conductors 133 and 134 are fixed by a dielectric (electrical insulator) embedded in an opening provided in the high-frequency reflector 160, and the conductors 133 and 134, the high-frequency reflector 160 and the like are fixed. Is not touching.
The dielectric substrate 142 and the conductors 133 and 134 may be in contact with the high frequency reflector 160.
Further, the other end portions of the conductors 133 and 134 and the dielectric substrate 142 may not penetrate the high-frequency reflection plate 160. In that case, it is connected to a feed line (not shown) on the surface side of the high-frequency reflector 160.

  Although not shown here, a conductor pattern for supplying a high-frequency band signal to the high-frequency vertically polarized antenna 130 is provided on the back surface of the dielectric substrate 142. This conductor pattern, together with the conductors 133 and 134, constitutes a microstrip line as well as a balance-unbalance converter.

The length between the outer ends of the element portions 131 and 132 in the longitudinal direction is set to a length _WH . The height from the surface of the high frequency reflector 160 to the center of the element portions 131 and 132 in the short direction is set to _HH . Further, the distance (gap) in the direction parallel to the surface of the high-frequency reflector 160 at the portion where the conductor patterns of the conductors 133 and 134 are opposed is the distance D _T on the side connected to the element portions 131 and 132, It is set to the interval _{D B} on the side closer to 160. The distance _{D B} closer to the high-frequency reflection plate 160 is larger configuration than the distance _{D T} of side connected to the element portion 131 and 132 (the side far from the high-frequency reflection plate 160) _(D B> D _T ).
Here, the height from the surface of the low-frequency reflecting plate 150 to the center of the element portions 131 and 132 in the short direction is an example of the second distance.

In a dipole antenna, in many cases, conductor portions (portions corresponding to the conductors 123 and 124 in FIG. 3A and the conductors 133 and 134 in FIG. 3B) that pass when power is supplied are perpendicular to the reflector. Provided.
In the antenna unit 110 to which the first embodiment is applied, the conductors 123 and 124 that pass when power is supplied to the low-frequency vertically polarized antenna 120 are provided perpendicular to the low-frequency reflector 150. That is, the distance between the conductor 123 and the conductor 124 in the direction parallel to the surface of the low-frequency reflector 150 is such that the side connected to the element portions 121 and 122 (the side far from the low-frequency reflector 150) and the low-frequency reflector 150 are connected. There is no difference on the side close to.
On the other hand, the conductors 133 and 134 that pass when the high-frequency vertically polarized antenna 130 is fed are provided obliquely with respect to the high-frequency reflector 160. That is, the distance between the conductor 133 and the conductor 134 in the direction parallel to the surface of the high frequency reflector 160 is the distance _DT on the side connected to the element portions 131 and 132 (the side far from the high frequency reflector 160) and the high frequency reflector 160. provided the difference between the near side of the gap D _B in, it is set such that the distance D _B is larger than the interval D _T. That is, the conductors 133 and 134 are configured in an inverted V shape so as to be separated from each other as they go from the side connected to the element units 131 and 132 (the side far from the high-frequency reflecting plate 160) to the side closer to the high-frequency reflecting plate 160. ing.

  The conductors 123 and 124 of the low-frequency vertically polarized antenna 120 are provided perpendicular to the low-frequency reflector 150, but may be provided obliquely.

  FIG. 4 is a diagram for explaining a modification of the sector antenna 10 to which the first embodiment is applied. The sector antenna 10 is configured by adding a parasitic element. The parasitic element is provided to match impedances in a wide frequency band and adjust the directivity and voltage standing wave ratio (VSWR) of the antenna unit 110, the array antenna 100, and the sector antenna 10. Note that VSWR is a numerical value indicating the degree of matching between the feeder line and the antenna that is a load, and is preferably closer to 1.

In FIG. 4, the array antenna 100 is assumed to include three antenna units 110.
Each antenna unit 110 has a predetermined distance in a direction away from the low frequency vertical polarization antenna 120a from the low frequency vertical polarization antenna 120a on the surface side of the low frequency reflection plate 150 provided with the low frequency vertical polarization antenna 120a. The parasitic element 171a is provided at the position along the element portions 121 and 122 (see FIG. 3A). Similarly to the low-frequency vertical polarization antenna 120a, a parasitic element 171b is provided for the low-frequency vertical polarization antenna 120b.
Each antenna unit 110 includes a parasitic element 172a provided on the surface side of the low-frequency reflector 150 so as to rise from the low-frequency reflector 150 on the outer side in the horizontal direction from the low-frequency vertically polarized antenna 120a. I have. Similarly, a parasitic element 172b provided so as to rise from the low-frequency reflector 150 is provided outside the low-frequency vertical polarization antenna 120b in the horizontal direction.

  Further, each antenna unit 110 is positioned at a predetermined distance in a direction away from the high frequency vertical polarization antenna 130a from the high frequency reflection plate 160 on the surface side of the high frequency reflection plate 160 provided with the high frequency vertical polarization antenna 130a. In addition, a parasitic element 173a is provided along the element portions 131 and 132 (see FIG. 3B). Similarly to the high-frequency vertically polarized antenna 130a, a parasitic element 173b is provided for the high-frequency vertically polarized antenna 130b.

  These parasitic elements 171a, 171b, 172a, 172b, 173a, 173b are provided to adjust the directivity and VSWR of the antenna unit 110, the array antenna 100, and the sector antenna 10. Therefore, the parasitic element is not limited to the above-described shape, position and number, and may be set so as to obtain a predetermined directivity and a predetermined VSWR ratio. Further, if a predetermined directivity and VSWR are obtained, the parasitic element need not be provided.

The antenna unit 110 shown in FIG. 2 combines two low-frequency vertically polarized antennas 120a and 120b and two high-frequency vertically polarized antennas 130a and 130b.
However, one low frequency vertical polarization antenna 120 and two high frequency vertical polarization antennas 130a and 130b may be combined, and two low frequency vertical polarization antennas 120a and 120b and one high frequency vertical polarization antenna 120a and 130b may be combined. The wave antenna 130 may be combined. Further, one low frequency vertical polarization antenna 120 and one high frequency vertical polarization antenna 130 may be combined.
Further, a combination of a plurality of antenna units 110 may be configured to include more than two low-frequency vertically polarized antennas 120 or more than two high-frequency vertically polarized antennas 130.

Furthermore, although the vertical polarization is transmitted and received here, the low frequency vertical polarization antenna 120 is rotated on the low frequency reflection plate 150 and the high frequency vertical polarization antenna 130 is rotated on the high frequency reflection plate 160 by 45 °. Thus, 45 ° polarization can be transmitted and received.
When the low-frequency vertical polarization antenna 120 and the high-frequency vertical polarization antenna 130 are rotated by 45 °, 45 ° polarization is transmitted and received instead of vertical polarization. Therefore, “vertical” may be read as “45 °”. The same applies to polarized waves of other angles.

[Second Embodiment]
The sector antenna 10 to which the first exemplary embodiment is applied is frequency sharing capable of transmitting and receiving vertically polarized waves.
The sector antenna 10 to which the second embodiment is applied is frequency sharing and polarization sharing that can share vertical polarization and horizontal polarization.
Hereinafter, the sector antenna 10 to which the second embodiment is applied differs from the sector antenna 10 to which the first embodiment is applied in the antenna unit 110. Therefore, below, it demonstrates focusing on the antenna unit 110 which is a different part, and abbreviate | omits description of the same part.

<Sector antenna 10, array antenna 100>
FIG. 5 is a diagram illustrating an example of the configuration of the sector antenna 10 to which the second embodiment is applied. Similar to FIG. 2, FIG. 5 is a perspective view of the sector antenna 10 placed sideways and viewed from an oblique direction.
The sector antenna 10 includes an array antenna 100 including antenna units 110-1, 110-2, and 110-3 arranged in a vertical direction, and a radome 500 that is housed so as to wrap the array antenna 100.
Also in FIG. 5, the radome 500 is indicated by a broken line so that the array antenna 100 provided inside the radome 500 can be seen.

<Antenna unit 110>
Similarly to the antenna unit 110 to which the first embodiment shown in FIG. 3 is applied, the antenna unit 110 includes two low-frequency vertically polarized antennas 120a and 120b that transmit and receive vertically polarized low-frequency bands. And two high-frequency vertically polarized antennas 130a and 130b that transmit and receive vertically polarized waves in a high frequency band.
Furthermore, the antenna unit 110 includes one low-frequency horizontal polarization antenna 180 that transmits and receives horizontal polarization in the low frequency band and two high-frequency horizontal polarization antennas 190a and 190b that transmit and receive high-frequency horizontal polarization. And.
When the high-frequency horizontally polarized antennas 190a and 190b are not distinguished from each other, they are described as the high-frequency horizontally polarized antenna 190.

The low-frequency horizontal polarization antenna 180 has the same shape as the low-frequency vertical polarization antenna 120 and is obtained by rotating the low-frequency vertical polarization antenna 120 by 90 ° on the low-frequency reflector 150. The element part (part corresponding to the element parts 121 and 122 in FIG. 3A) included in the low-frequency horizontally polarized antenna 180 is an example of a third dipole antenna. The height of the element portion from the low frequency reflection plate 150 is an example of the third distance.
The high-frequency horizontal polarization antenna 190 has the same shape as the high-frequency vertical polarization antenna 130 and is obtained by rotating the high-frequency vertical polarization antenna 130 by 90 ° on the high-frequency reflector 160. The element part (part corresponding to the element parts 131 and 132 in FIG. 3B) provided in the high-frequency horizontally polarized antenna 190 is an example of a fourth dipole antenna. The height of the element portion from the low frequency reflection plate 150 is an example of the fourth distance.

The low-frequency horizontal polarization antenna 180 is arranged on the surface side of the low-frequency reflector 150 at the center of each of the two high-frequency vertical polarization antennas 130a and 130b (where the element portions 121 and 122 in FIG. 3 face each other). ).
A high-frequency reflector 160 is provided with the low-frequency vertically polarized antennas 120a and 120b interposed therebetween. Therefore, an opening is provided in the high-frequency reflector 160, and the other end portion of the conductor portion of the low-frequency horizontally polarized antenna 180 (corresponding to the conductors 123 and 124 in FIG. 3A) (see FIG. 3). ) Extends toward the low-frequency reflector 150.

On the other hand, the high-frequency horizontally polarized antenna 190a is on the surface side of the high-frequency reflector 160, and its element portions (portions corresponding to the element portions 131 and 132 in FIG. 3B) are elements of the high-frequency vertically polarized antenna 130a. The parts 131 and 132 are configured to be combined with each other. That is, when viewed toward the high-frequency reflector 160, the element portions 131 and 132 of the high-frequency vertically polarized antenna 130a and the element portions of the high-frequency horizontally polarized antenna 190a are combined to form a cross.
The high-frequency vertical polarization antenna 130b and the high-frequency horizontal polarization antenna 190b are combined in the same manner.

By doing in this way, the antenna unit 110, the array antenna 100, and the sector antenna 10 are shared in polarization in addition to frequency sharing.
Note that either high frequency or low frequency may be shared by polarization.

FIG. 6 is a diagram for explaining a modification of the sector antenna 10 to which the second embodiment is applied. The sector antenna 10 is configured by adding a parasitic element to the sector antenna 10 of FIG.
Each antenna unit 110 is similar to the antenna unit 110 to which the first embodiment shown in FIG. 4 is applied, and includes a parasitic element 171a for the low-frequency vertical polarization antenna 120a and a low-frequency vertical polarization antenna 120b. The parasitic element 171b, the low-frequency vertical polarization antenna 120b, the parasitic element 172a provided outside in the horizontal direction from the low-frequency vertical polarization antenna 120a, and provided outside in the horizontal direction from the low-frequency vertical polarization antenna 120b. A parasitic element 172b is provided.

  Further, each antenna unit 110 includes a parasitic element 174 similar to the parasitic element 171a for the low-frequency vertical polarization antenna 120a with respect to the low-frequency horizontal polarization antenna 180.

Further, the element portion 131 of the high-frequency vertical polarization antenna 130a is located at a predetermined distance in the direction away from the high-frequency reflector 160 from the combined antenna of the high-frequency vertical polarization antenna 130a and the high-frequency horizontal polarization antenna 190a. , 132 and a cross-shaped parasitic element 176a arranged so as to extend in the direction of the element portion of the high-frequency horizontal polarization antenna 190a (the portion corresponding to the element portions 131 and 132 in FIG. 3B). It has been.
Also, an antenna in which the high-frequency vertical polarization antenna 130b and the high-frequency horizontal polarization antenna 190b are combined also has a cross shape similarly to the antenna in which the high-frequency vertical polarization antenna 130a and the high-frequency horizontal polarization antenna 190a are combined. A parasitic element 176b having a shape is provided.

  FIG. 7 is a diagram illustrating an example of directivity in a horizontal plane with respect to vertical polarization in a low frequency band of the array antenna 100 to which the second embodiment is applied. FIG. 7A is a diagram for explaining the array antenna 100. FIG. 7B shows the directivity in the horizontal plane with respect to the vertical polarization of the low frequency band of the array antenna 100 shown in FIG. 7A. FIG.

As shown in FIG. 7A, the array antenna 100 shown in FIG. 6 was used. That is, the antenna unit 110 in the array antenna 100 is used for both frequency sharing and polarization sharing. Furthermore, a parasitic element is provided.
The directivity shown in FIG. 7B is a calculation example at the design frequency f _L in the low frequency band. The wavelength of the design frequency f _{L in} the low frequency band is λ _L , and the wavelength of the design frequency f _{H in} the high frequency band is λ _H.

Here, in FIG. 3 (a), the low frequency the length _{W L} of about 0.5 [lambda _L between the longitudinal direction of both outer ends of the elements 121, 122 of the vertically polarized antenna 120, short of the element 121, 122 the height H _L from the surface of the hand direction of a center of the low frequency reflector 150 is set to about 0.25 [lambda _L.
In FIG. 3B, the length W _H between the outer ends in the longitudinal direction of the element portions 131 and 132 of the high-frequency vertically polarized antenna 130 is about 0.5λ _H , and the width direction of the element portions 131 and 132 is short. the height _{H H} from the surface of the center of the high frequency reflection plate 160 is set to about 0.25 [lambda _H.
Further, the interval _{D B} at the side closer to the high-frequency reflection plate 160 of the conductor 133 and 134 is set to about 0.27λ _H.

Low frequency vertically polarized antenna 120a, and sends a signal of vertical polarization of the design frequency f _L of the low frequency band 120b, horizontally polarized signal design frequency f _L of the low frequency band to the low frequency horizontal polarization antenna 180 transmits a high-frequency vertically polarized antenna 130a, and sends a signal of vertical polarization of the design frequency _{f H} of the high frequency band 130b, the high frequency horizontal polarization antenna 190a, a design frequency _{f H} of the high frequency band 190b By transmitting a horizontally polarized signal, the directivity in the horizontal plane of the vertically polarized wave of the design frequency f _{L in} the low frequency band was obtained by simulation.

  As shown in FIG. 7B, in the array antenna 100 to which the second embodiment is applied, side lobes are suppressed and the back lobe is −17 dB compared to the case of FIG. 8B described later. And small. The beam width at −3 dB is about 90 °.

  FIG. 8 is a diagram for explaining an example of directivity in the horizontal plane with respect to vertical polarization in the low frequency band of the array antenna 100 to which the second embodiment is not applied. FIG. 8A is a diagram for explaining the array antenna 100, and FIG. 8B shows the directivity in the horizontal plane with respect to the vertical polarization of the low frequency band of the array antenna 100 shown in FIG. 8A. FIG.

As shown in FIG. 8A, in the array antenna 100 to which the second embodiment is not applied, instead of the high frequency vertical polarization antennas 130a and 130b shown in FIG. 130d, and high-frequency horizontally polarized antennas 190c and 190d are used in place of the high-frequency horizontally polarized antennas 190a and 190b, respectively.
The high-frequency vertical polarization antennas 130 c and 130 d have conductor portions (portions corresponding to the conductors 133 and 134 in FIG. 3B) provided perpendicular to the high-frequency reflector 160. The same applies to the high-frequency horizontally polarized antennas 190c and 190d. That is, the distance (gap) between the conductor portions (portions corresponding to the conductors 133 and 134 in FIG. 3B) of the high-frequency vertically polarized antenna 130 is far from the side connected to the element portions 131 and 132 (far from the high-frequency reflector 160). Side) and the side close to the high frequency reflector 160 are not different.
Other configurations of the antenna unit 110 are the same as those of the antenna unit 110 of the array antenna 100 to which the second embodiment shown in FIG. 7A is applied.

The signals transmitted to the low-frequency vertical polarization antennas 120a and 120b and the low-frequency horizontal polarization antenna 180, the high-frequency vertical polarization antennas 130c and 130d, and the signals transmitted to the high-frequency horizontal polarization antennas 190c and 190d are the second Array antenna 100 to which the embodiment is applied
Is the same as

  As shown in FIG. 8B, the array antenna 100 to which the second embodiment is not applied has a large side lobe and a large back lobe of −7 dB compared to the case of FIG. The beam width at −3 dB is about 90 °.

As described above, the configuration of the antenna unit 110 (shapes), a difference in directivity of vertically polarized waves in the horizontal plane of the frequency f _L of the low frequency band was seen.
As shown in FIGS. 7A and 8A, there is no difference in the configuration (shape) of the low-frequency vertically polarized antennas 120a and 120b. Nevertheless, due to the difference in configuration (shape) between the high-frequency vertical polarization antennas 130a and 130b shown in FIG. 7A and the high-frequency vertical polarization antennas 130c and 130d shown in FIG. The directivity in the horizontal plane in the vertical polarization of the frequency f _L is affected.

In the antenna unit 110 to which the second embodiment shown in FIG. 7A is applied, the conductors 133 and 134 in the high-frequency vertical polarization antenna 130 (high-frequency vertical polarization antennas 130 a and 130 b) in a direction parallel to the surface, greater than the distance _{D T} of the side spacing _{D B} closer to the high-frequency reflection plate 160 is connected to the element portion 131 and 132 (the side far from the high-frequency reflection plate 160) (wide) is set .
Thus, even if the low-frequency vertical polarization antenna 120 and the high-frequency vertical polarization antenna 130 are arranged side by side in a direction intersecting the vertical polarization direction, the frequency f _H of the high-frequency band by the high-frequency vertical polarization antenna 130 is arranged. The influence on the directivity in the horizontal plane of the vertically polarized wave of the frequency f _{L in} the low frequency band due to the vertically polarized wave can be suppressed.

This is because a current is induced in the high frequency vertical polarization antenna 130 by the vertical polarization of the low frequency band frequency f _L from the low frequency vertical polarization antenna 120, thereby causing a vertical polarization of the low frequency band frequency f _L. It is thought that there is an effect on the directivity of waves in the horizontal plane.
Then, it is considered that the electric field generated between the conductor 133 and the conductor 134 of the high frequency vertical polarization antenna 130 affects the current induced in the high frequency vertical polarization antenna 130. Therefore, it is considered that reducing the electric field strength by increasing the distance between the conductor 133 and the conductor 134 in the high-frequency vertical polarization antenna 130 is effective in reducing the current induced in the low-frequency vertical polarization antenna 120 (FIG. 3).
However, the distance D _T (see FIG. 3B) between the conductor 133 and the conductor 134 on the side connected to the element portions 131 and 132 (the side far from the high-frequency reflector 160) in the high-frequency vertically polarized antenna 130 is high-frequency vertical. Since it is set according to the characteristics of the polarization antenna 130, it cannot be expanded. Therefore, the distance D _B (see FIG. 3B) between the conductor 133 and the conductor 134 on the side close to the high-frequency reflector 160 is widened.
In the above description, vertical polarization has been described, but the same applies to horizontal polarization.

In the above description, the polarization-sharing array antenna 100 has been described. However, in the frequency-sharing array antenna 100 that transmits and receives the vertical polarization described in the first embodiment, the low-frequency vertical polarization antenna 120 and the high-frequency vertical antenna are also used. Even if the polarization antenna 130 is arranged side by side in a direction intersecting the direction of vertical polarization, the influence of the high-frequency vertical polarization antenna 130 on the directivity in the horizontal plane of the vertically polarized wave of the frequency f _{L in} the low frequency band Can be suppressed.

  The array antenna 100 shown in FIG. 7A includes parasitic elements 171a, 171b, 172a, 172b, 174, 176a, and 176b. However, as described above, the parasitic element matches the impedance of the antenna unit 110 in a wide frequency band, such as the directivity of the antenna unit 110, the array antenna 100, and the sector antenna 10, and the voltage standing wave ratio (VSWR). It is provided to adjust the characteristics. Therefore, a parasitic element may be provided so that the antenna unit 110, the array antenna 100, and the sector antenna 10 have predetermined characteristics. Therefore, the shape, number, and arrangement of the parasitic elements may be different from the configuration illustrated in FIG. Further, a parasitic element need not be used.

Furthermore, although vertical polarization and horizontal polarization are transmitted and received here, the low-frequency vertical polarization antenna 120 and the low-frequency horizontal polarization antenna 180 are placed on the low-frequency reflector 150 and the high-frequency vertical polarization antenna 130 and the high-frequency antenna. By rotating the horizontal polarization antenna 190 on the high-frequency reflector 160 by 45 °, ± 45 ° polarization can be transmitted and received.
When the low-frequency vertical polarization antenna 120, the low-frequency horizontal polarization antenna 180, the high-frequency vertical polarization antenna 130, and the high-frequency horizontal polarization antenna 190 are rotated by 45 °, ± 45 instead of vertical polarization and horizontal polarization. It transmits and receives ° polarization. Therefore, “vertical” and “horizontal” may be read as “45 °” and “−45 °”. The same applies to polarized waves of other angles.

DESCRIPTION OF SYMBOLS 1 ... Base station antenna, 2 ... Cell, 3, 3-1 to 3-3 ... Sector, 10, 10-1 to 10-3 ... Sector antenna, 11 ... Main lobe, 20 ... Steel tower, 31, 32 ... Transmission / reception cable , 100 ... Array antenna, 110, 110-1 to 110-3 ... Antenna unit, 120, 120a, 120b ... Low frequency vertical polarization antenna, 121, 122, 131, 132 ... Element part, 123, 124, 133, 134 ... Conductor, 130, 130a, 130b, 130c, 130d ... High-frequency vertically polarized antenna, 150 ... Low-frequency reflector, 160 ... High-frequency reflector, 171a, 171b, 172a, 172b, 173a, 173b, 174, 176a, 176b ... Parasitic element, 180 ... low frequency horizontally polarized antenna, 190, 190a, 190b, 190c, 190d ... high frequency Flat polarized antenna, 500 ... radome

For this purpose, an antenna to which the present invention is applied is a first dielectric that is provided at a predetermined first distance from the reflector and transmits and receives radio waves in the first frequency band. The first dipole antenna configured on the substrate and the first dipole antenna side of the reflector are provided at a predetermined second distance from the reflector and are higher than the first frequency band. A second dipole antenna configured on a second dielectric substrate that transmits and receives radio waves in the second frequency band , and the second dipole antenna transmits and receives radio waves in the second frequency band. It is characterized by having two element portions and two conductors provided obliquely from each of the two element portions toward the reflecting plate and having a wider distance on the side closer to the reflecting plate than on the far side.

And, on the side where the first dipole antenna is provided on the reflecting plate, a third radio wave which is provided at a predetermined third distance from the reflecting plate and which crosses the first dipole antenna is transmitted and received. A third dipole antenna configured on the dielectric substrate and a second dipole provided at a predetermined fourth distance from the reflector on the side of the reflector where the first dipole antenna is provided. transmitting and receiving radio waves of polarization intersecting the antenna can feature a fourth dipole antenna configured the fourth dielectric substrate, of further comprising at least either one.
According to this configuration, polarization can be shared compared to the case without this configuration.

From another point of view, a sector antenna to which the present invention is applied is provided with a reflector, a first distance predetermined from the reflector, and transmits and receives radio waves in the first frequency band . The first dipole antenna configured on the dielectric substrate and the first dipole antenna provided on the side of the reflector provided at a predetermined second distance from the reflector, the first frequency band An array antenna including a plurality of antennas including a second dipole antenna configured on a second dielectric substrate that transmits and receives radio waves in a higher second frequency band ; and a radome that houses the array antenna; It comprises a second dipole antenna in the antenna includes two element portions for transmitting and receiving radio waves in the second frequency band from each of the two element portions provided obliquely toward the reflector, the reflection And having a two conductor wider spacing than the side is on the far side closer to.
According to this configuration, the sector antenna can be made smaller than in the case without this configuration.

Claims (4)

A reflector,
A first dipole antenna provided at a predetermined first distance from the reflector and transmitting / receiving radio waves in a first frequency band;
Transmitting and receiving radio waves in a second frequency band higher than the first frequency band, provided at a second predetermined distance from the reflector on the side of the reflector where the first dipole antenna is provided. A second dipole antenna that
The two dipole antennas that configure the second dipole antenna and transmit and receive radio waves in the second frequency band are provided from each of the element portions toward the reflecting plate, and an interval in a direction parallel to the reflecting plate is spaced from the reflecting plate. An antenna provided with a wider conductor on the side closer to the side than on the far side. On the side of the reflector on which the first dipole antenna is provided, the reflector is provided at a predetermined third distance from the reflector, and transmits and receives polarized radio waves intersecting the first dipole antenna. 3 dipole antennas,
On the side of the reflector on which the first dipole antenna is provided, the reflector is provided at a predetermined fourth distance from the reflector, and transmits and receives polarized radio waves intersecting with the second dipole antenna. The antenna according to claim 1, further comprising at least one of four dipole antennas.   The antenna according to claim 1, further comprising a parasitic element. A reflector, a first dipole antenna provided at a predetermined first distance from the reflector and transmitting / receiving radio waves in the first frequency band, and the first dipole antenna of the reflector are provided. A second dipole antenna provided at a predetermined second distance from the reflector and transmitting / receiving radio waves in a second frequency band higher than the first frequency band; and the second dipole A side that is provided toward each of the reflecting plates from each of the two element units that transmit and receive radio waves in the second frequency band by configuring the antenna, and the side in the direction parallel to the reflecting plate is farther from the side closer to the reflecting plate An array antenna having a plurality of antennas each having a wider conductor than
A sector antenna comprising a radome that houses the array antenna.

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