KR101111578B1 - Dual polarized antenna for bidirectional communication - Google Patents

Abstract

The dual polarized bidirectional antenna according to the present invention is formed on the reflecting plate, the two facing each other on the reflecting plate and formed on the reflecting plate in the orthogonal direction between the dipole element and the dipole element of the horizontal polarization characteristics that are in antiphase with each other By including omni antenna elements having vertical polarization characteristics that are in phase with each other, vertical polarization and horizontal polarization can be radiated in both directions.

Description

DUAL POLARIZED ANTENNA FOR BIDIRECTIONAL COMMUNICATION}

The present invention relates to a dual polarized bidirectional antenna, and more particularly, to an antenna that radiates both vertical and horizontal polarized waves in both directions.

An antenna is a conductor laid in the air in order to efficiently radiate radio waves into a space in order to achieve the purpose of communication in wireless communication or to efficiently dissipate electromotive force by radio waves. That is, a device for transmitting or receiving electromagnetic waves to a space for transmitting and receiving is called an aerial in the UK. The term antenna means the tactile sense of insects, and this name comes from acting like a tactile sense of catching radio waves. Aerial means "public," and antennas are called aerials.

The transmitting and receiving antennas have the same basic principle, but the shape varies in accordance with the frequency (wavelength) used. In order to operate the antenna efficiently, it is necessary to resonate at the frequency using the antenna. Vertical antennas, also referred to as coaxial antennas or sleeve antennas, resonate when their length is 1/4 or 1/2 of the wavelength used, but in practice, the antennas are too long and are resonated using coils or capacitors. In short and ultrashort waves, the wavelength is short, so half-wavelength antennas are used. Coaxial antennas are commonly used as transmit / receive antennas for communication devices using taxi radios or other microwaves.

The radio waves radiated from the antenna are polarized because the energy of the electromagnetic field propagates in the form of waves. Polarization refers to one or such wave itself having certain properties in the direction of its vibration in light or propagation.

In general, the electric field vector oscillates in a plane perpendicular to the direction of travel of the wave. The plane created by the electric field vector and the direction of wave propagation is called a polarization plane. Waves with a polarized plane perpendicular to the earth are called vertical polarizations and waves parallel to the earth are called horizontal polarizations. The wave whose end of the electric field vector is circular is called circular polarization.

In the case of vertical polarization and horizontal polarization, a normal antenna system is implemented only when both a transmitting and receiving antenna can radiate and receive the same polarization. In such a situation, in order to keep pace with the diversified communication environment, antennas emitting both vertical and horizontal polarizations have attracted attention.

The present invention provides a dual polarization that radiates both a vertical polarization that is a linear polarization such that the electric field of the radio wave is perpendicular to the reflection plane or the ground, and a horizontal polarization that is a linear polarization such that the electric field of the radio wave is horizontal with respect to the reflection plane or the ground. To provide a bidirectional antenna.

The dual polarized bidirectional antenna of the present invention for achieving the above object is formed in the orthogonal direction between a dipole element and a dipole element of a horizontal polarization characteristic in which two are formed facing each other on the reflecting plate and the radiating radio waves are reversed to each other. Two may be formed facing each other on the reflecting plate, and may include an omni antenna element having vertical polarization characteristics in which radiating radio waves are in phase with each other.

At this time, the omni-feeding unit of the same length for feeding each of the omni antenna elements and a dipole feeding portion of the same length for feeding each of the dipole elements, each of the dipole elements and the left and the right relative to the direction viewed from the facing element Consists of two elements on the right side, a feed point may be formed on the same element side of the two elements.

The apparatus may further include an omni-feeding unit having a same length for feeding each of the omni antenna elements and a dipole feeding unit having different lengths for feeding signals that are out of phase with each other, respectively. Feed points may be formed on different elements of the elements.

In addition, the center between the omni antenna elements may be the same as the center between the dipole elements.

In addition, the dipole element may be bent such that the surface of the element is parallel to the reflecting plate.

The dipole element may include a fixing member fastened on the reflecting plate, a balloon extending in an upper direction of the upper surface of the reflecting plate in a state separated into two from the fixing member, and a horizontal direction of the reflecting plate at the ends of the respective baluns. It may comprise two elements extending in opposite directions to each other.

In this case, the balloon may be bent such that the surface of the element is parallel to the reflecting plate.

In addition, the omni antenna element may include an element fastened vertically on the reflector.

The distance between the dipole elements and the distance between the omni antenna elements may be 0.3 lambda or more within a 0.8 lambda range of each frequency wavelength.

In addition, the reflecting plate may be cut a portion of the end located in the radial direction of the dipole element.

In this case, the reflector may be installed in close contact with one of the linear wall, ceiling, floor.

As described above, the dual polarized bidirectional antenna of the present invention faces each other and has two horizontal polarized wave dipoles having an inverse phase and two vertically polarized omni antenna elements having an in-phase and orthogonal to each other on a reflector. By forming, both horizontal and vertical polarizations are radiated in both directions.

By arranging a dual polarized bidirectional antenna having such a property in a space having a straight line such as a corridor, the space can be efficiently covered.

In addition, by bending the element surface of the dipole element to be parallel to the reflector, the isolation characteristics and radiation pattern can be improved, and the entire antenna can be made slim. Due to the slimness, it is possible to equip more places, and especially when installed in a place that is exposed to the outside such as a ceiling, it can provide an appearance that is harmonious with surrounding places without disturbing the movement of passengers.

In addition, the radiation pattern may be improved by cutting a portion of the tip located in the radial direction of the dipole element in the reflector. In particular, when the reflector is installed in close contact with the wall, the ceiling and the floor, the tilt of the effective space is increased instead of the tilt toward the wall, the ceiling and the floor, so that the coverage area is relatively expanded.

1 is a schematic diagram illustrating a dual polarized bidirectional antenna associated with the present invention.
Figure 2 is a plan view schematically showing a dual polarized bidirectional antenna associated with the present invention.
Figure 3 is a schematic diagram showing a dipole element of a dual polarized bidirectional antenna according to another embodiment related to the present invention.
Figure 4 is a graph showing a horizontal pattern and a vertical pattern of horizontal polarization in a dual polarized bidirectional antenna according to the present invention.
5 is a graph showing a horizontal pattern and a vertical pattern of vertical polarization in a dual polarized bidirectional antenna according to the present invention.
6 is a schematic view showing a state in which a dipole element is not bent in a dual polarized bidirectional antenna according to the present invention.
7 is a schematic diagram showing a dipole element of a dual polarized bidirectional antenna according to another embodiment related to the present invention.
FIG. 8 is a graph showing isolation characteristics before and after bending a dipole element in a dual polarized bidirectional antenna according to the present invention so that an element plane is parallel to a reflector. FIG.
9 is a graph showing a radiation pattern before and after bending a dipole element so that an element plane is parallel to a reflector in a dual polarized bidirectional antenna according to the present invention.
10 is a graph showing a vertical radiation pattern before and after cutting a portion of the end of the reflector located in the radial direction of the dipole element in the dual polarized bidirectional antenna according to the present invention.

Hereinafter, a dual polarization bidirectional antenna according to the present invention will be described in more detail with reference to the accompanying drawings.

1 is a schematic diagram illustrating a dual polarized bidirectional antenna according to the present invention, and FIG. 2 is a plan view schematically illustrating a dual polarized bidirectional antenna according to the present invention. Figure 3 is a schematic diagram showing a dipole element of a dual polarized bidirectional antenna according to another embodiment related to the present invention.

The dual polarized bidirectional antenna shown in FIG. 1 is formed on the reflecting plate 110, on the reflecting plate in the orthogonal direction between the dipole element 130 and the dipole element having a horizontal polarization characteristic which are formed opposite to each other on the reflecting plate. Two are formed facing each other, and includes an omni antenna element 150 of vertical polarization characteristics that are in phase with each other.

The reflector 110 may be configured in various forms, and in the embodiment of FIG. 1, the reflector 110 is formed in a planar shape of a square. At this time, the dipole element 130 and the omni antenna element 150 are installed at the central portion of each side.

Two dipole elements 130 are disposed to face each other on a reflecting plate, and each dipole element is configured to be 180 degrees out of phase, that is, out of phase. When the dipole elements facing each other are reversed in phase, a beam (horizontal polarization) synthesized by the two dipole elements is radiated in the direction of an imaginary line across the two dipole elements. Specifically, as shown in FIG. 2, when the dipole elements are formed on the left and right sides of the reflecting plate, the synthesized beams are also radiated in the a direction (both directions) in the left and right directions. In such a configuration, when the vertical polarization is also radiated in the a direction, a dual polarized bidirectional antenna in which both the vertical polarization and the horizontal polarization are radiated in the a direction (bidirectional) is completed. Radiation of vertical polarization is mentioned later.

In order to make the phase difference between the dipole elements 180 degrees, the feeding position of each dipole element may be used, or the length of the feeding part where the feeding is made may be used.

The method of using the feeding positions between the dipole elements uses the structure of the dipole elements. The dipole element 130 has two elements 133 extending in opposite directions as addresses. A fixing member 137 and a balloon 135 may further be included to place the element in the air on the reflector.

The fixing member 137 is fastened on the reflector and may be one end of the balun depending on the fastening method. For example, the fixing member in the form of a plate in FIG. 1 may be removed, and the balloon may be fastened by standing directly on the reflector. At this time, the fastening part (fastening surface) of a balloon and a reflecting plate becomes a fixing member.

The balloon 135 is configured in an appropriate shape for individually supporting each element, and extends in the upper direction (air direction) of the upper surface of the reflecting plate in two separated states from the fixing member to support the element. In general, as shown in FIG. 1, the reflection plate may extend in a vertical direction but is not limited thereto. According to the configuration of the dipole device, a feed point 131 may be formed in the balloon as illustrated in FIG. 1.

Element 133 extends in the horizontal direction of the reflector at the end of each balun to emit and receive horizontal polarizations. Two elements are formed per dipole element and extend in opposite directions. The overall shape formed by the balloon and the element becomes 'T' shape, where the length of the head, ie the distance between the ends of each element, may be 0.5λ. In order to improve the isolation property and the radiation pattern, the element 133 is preferably bent so that the surface thereof is parallel to the reflector. For this purpose, the balun 135 may be bent.

In order to emit and receive horizontal polarization in the element, a power supply must be made through the feed point 131. As shown in FIG. 3, when the feed points are formed on the same element side in two dipole elements and face each other, the feed points are formed in a diagonal direction. When power is supplied in this state, the two dipole elements exhibit a 180 degree phase difference. Accordingly, the beam (horizontal polarization) synthesized by the radiation from each dipole element is emitted in the direction of the imaginary line crossing each dipole element. For reference, the feeding of the element may be made through a feeding part covering two elements spaced apart from the element by a predetermined distance, but the configuration and structure of the element are not shown because they are very diverse. The feed point may be formed in the balloon or the feed portion.

It is preferable that the substantial distance d1 between the dipole elements satisfies the range of 0.3 lambda or more within the 0.8 lambda range of the frequency wavelength in accordance with the relationship between the optimization adjustment of the radiation range and the omni antenna element as the distance between the centers of the elements. If less than 0.3λ, since the beam is not synthesized much, the transmission / reception gain increase is small, and if it exceeds 0.8λ, the sidelobe is increased and the beam is not properly synthesized.

In the above, the method of making the dipole elements out of phase with each other by using the feed position of each dipole element has been described. As a premise, the length of the feeding part for feeding power to the dipole element should be the same. The feeding part referred to herein includes all means for connecting the element 133 and the external feed point 171 formed on the reflector to connect with the external feed line. For example, in FIG. 1, the feed line 170 connecting the external feed point 171 and the feed point 131 formed in the balun and the balun portion from the feed point 131 formed in the balun to the element become a feeding part. Accordingly, the length of the feeding portion is the sum of the lengths of the balun portions from the feed point 131 formed in the balun to the element with the length of the feed line. Such a feeding part is formed for each dipole element, and the dipole elements are reversed only when the feed points are formed on the same element side in the same length. If the length of the feeding part is different, the delay of the signal is different and the phase is out of order. For reference, the feeding portion for the dipole element is called a dipole feeding portion, and the feeding portion for the omni antenna element is called an omni feeding portion. The feed line may be a wiring pattern formed on a PCB or the like as well as a cable line.

On the other hand, the phase between the dipole elements can be 180 degrees by using the signal delay according to the feeding part length. For example, in FIG. 1, when the length of the left dipole feeding portion is longer than the length of the right dipole feeding portion, the signal fed to the left dipole element is delayed by the difference in length, and thus has a phase different from that of the right dipole element. Therefore, if the lengths of the dipole feeding portions are appropriately different, the phase between the dipole elements can be reversed. Of course, each of the dipole elements at this time, the feed point should be formed on the side of the different elements of the two separate elements. When the feed point is formed as described above, unlike FIG. 1 and 2, the feed point is formed on the same line facing each other so that there is no phase change due to the difference in the feed point, and instead, the feed point has a phase difference due to the difference in length of the dipole feeding part.

Two omni antenna elements 150 are disposed on the reflecting plate so as to face each other. Two omni antenna elements are arranged in the orthogonal direction of the imaginary line across the two dipole elements. When the centers of the omni antenna elements are different from the centers of the dipole elements, interference between the vertical polarization emitted by the omni antenna elements and the horizontal polarization emitted by the dipole elements may be increased and the areas covered by the dipole elements may be different. Therefore, the center between the omni antenna elements is preferably the same as the center between the dipole elements.

The omni antenna element includes an element formed perpendicular to the reflector to emit vertical polarization. For example, omni antenna elements can be constructed by fastening elements vertically on a reflector. In this case, the omni antenna element 150 is configured only by the element itself. When the two omni antenna elements disposed on the reflecting plate are arranged in phase, the synthesized beam (vertical polarization) is radiated in the direction of the imaginary line across the two dipole elements, similar to the beam synthesized in the dipole element. The direction becomes the a direction in FIG. Therefore, when the two dipole elements having an inverse phase are formed to face each other, and the two omni antenna elements having the same phase in the orthogonal direction are formed to face each other, a dual polarized bidirectional antenna is completed.

In the case of the omni antenna element, it is difficult to change the phase by using the position of the feed point, so that the phase difference is formed by adjusting the length of the feeding part, that is, the omni feeding part, of the omni antenna element. In order to equalize the phase between the omni antenna elements, the length of the omni-feeding portion for each omni antenna element must be the same.

The distance d2 between the omni antenna elements is the distance from the center of the omni antenna element formed on one side to the center of the omni antenna element formed on the other side, and can be changed to have an optimal antenna performance at 0.3 lambda or more within the 0.8 lambda range of the frequency wavelength. .

In summary, the dual polarized bidirectional antenna according to the present invention is an omni antenna element having a vertical polarization characteristic having two phase polarization characteristics having an inverse phase and two polarized polarization polarization characteristics so that the vertical polarization and the horizontal polarization are directed in the same bidirectional direction. Two are formed facing each other on the reflecting plate. As a first method to have the phase as described above, when the omni-feeding unit having the same length for feeding each of the omni antenna elements and the dipole feeding unit having the same length for feeding each of the dipole elements, each of the dipole elements is one of two separate elements. A feed point may be formed on the same element side. In a second scheme, an omni-feeding unit of equal length for feeding each of the omni antenna elements and a dipole-feeding unit of different lengths for feeding each of the dipole elements to be out of phase with each other, wherein each of the dipole elements are separated from each other in two separate elements Feed points may be formed on the other element side. The first scheme uses the structure of the dipole element so that the two dipole elements are out of phase according to the feed point position, and the second scheme uses the length of the dipole feeding portion to make the two dipole elements out of phase.

In FIG. 1 having the configuration according to the first scheme, the center between the dipole elements 130 and the omni antenna element 150 are the same, and the element 133 surface of the dipole element is formed horizontally with the reflecting plate 110. In addition, as shown in FIG. 3, a feed part 139 is formed in parallel with the element and the balloon 135 in the direction of the upper surface of the element in a horizontal state with a reflecting plate, and a feed point 131 is formed near one end of the feed part. The dual polarized antenna radiation pattern at is as shown in FIGS. 4 and 5. The distance between the dipole elements is 0.7λ and the distance between the omni antenna elements is 0.5λ. A fastening means 138, such as a synthetic resin material, which is a non-conductor, is used to form a feed section in parallel with the element and the balloon.

4 shows a horizontal pattern (left) and a vertical pattern (right) of a horizontal polarization in a dual polarized bidirectional antenna according to the present invention.

Looking at the radiation can be seen in the left and right directions corresponding to -90, +90. 5 shows a horizontal pattern (left) and a vertical pattern (right) of vertical polarization in a dual polarized bidirectional antenna according to the present invention.

As in the horizontal polarization, radiation occurs in the left and right directions corresponding to -90 and +90. Therefore, it can be seen that both horizontal and vertical polarizations radiate in the same direction.

On the other hand, in the dipole element, even if the element surface is not bent to be parallel to the reflector as shown in FIG. 6, the horizontal polarization is emitted in both directions. In this state, the element plane is parallel to the reflector to improve the isolation characteristics and radiation pattern. In addition, bending the dipole element can reduce the height of the entire antenna, thereby making it slimmer.

FIG. 7 illustrates a dipole element of a dual polarized bidirectional antenna according to another exemplary embodiment of the present invention. Unlike FIG. 3, the power supply unit 139 is formed in the lower surface of the element 133. At this time, the feed point 131 is formed in the balloon 135. Other configurations are the same as those of FIG. 3, and the antenna characteristics when the dipole element is not bent as shown in FIG.

FIG. 8 illustrates isolation characteristics before and after bending a dipole element such that an element plane is parallel to a reflector in a dual polarized bidirectional antenna according to the present invention.

In the graph, the lower the measured value, the better the isolation property. The isolation property after the bending treatment is improved compared to the isolation property before the bending treatment.

FIG. 9 is a graph illustrating a radiation pattern before and after bending a dipole element in a dual polarized bidirectional antenna according to the present invention so that an element plane is parallel to a reflector. The radiation pattern after the bending treatment has wider coverage than the radiation pattern before the bending treatment, and the smaller the radiation crosslinking pattern, the less favorable the cross-polarization pattern is after the bending treatment.

Since the dual polarized bidirectional antenna described above emits the synthesized beam in both directions, it is suitable for installation in the middle of a space having a straight line. Such a space can be, for example, a corridor. In the case of a corridor, it is not desirable to install an antenna at the center point of the corridor because the convenience of traffic should be a top priority. The reflector will thus be fitted to the wall or floor, preferably the ceiling. In this arrangement, a large portion of the emitted beam is obstructed by the surfaces of the walls, floors, and ceilings, which places a considerable limitation on the antenna side. Therefore, it is possible to cut a part of the end of the reflector located in the radial direction of the dipole element in order to radiate the beam to the space of the straight line as far as possible, not the surface of the wall, floor or ceiling. When a part of the end of the reflecting plate to be cut in this manner is called the cut portion 111, the size and shape of the cut portion can be variously changed. In FIG. 1, a cutout having a rectangular shape is formed, and antenna characteristics before and after the cutout are formed are as shown in FIG. 10.

FIG. 10 is a graph showing a vertical radiation pattern before and after cutting a part of an end of a reflecting plate located in a radial direction of a dipole element in a dual polarized bidirectional antenna according to the present invention.

Looking at it, it can be seen that the tilt angle of the beam after cutting is larger than the tilt angle of the beam before cutting and is wider at the 0 degree reference, and the cover area is wider. It can be seen that the beam peak also increases with reference to 0 degrees. In other words, the beam directing direction moves in the upper surface direction of the reflecting plate on which the dipole element is formed.

As a result, a larger cover area can be taken for the space in which the beam is to be emitted.

On the other hand, those skilled in the art will appreciate that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. Therefore, the above-described embodiments are to be understood as illustrative in all respects and not as restrictive. The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

For example, a cutout may be further formed at the end of the omni antenna element side in the reflector.

It can be applied to the antenna to emit the horizontal and vertical polarization in both directions. In particular, it is useful for an antenna installed in the center of a space such as a corridor.

In addition, the antenna may be used as an antenna supporting LTE (long term evolution), which is a high-speed wireless data packet communication standard 12 times faster than HSDPA (high-speed downlink packet access).

110 ... Reflector 111 ... Cutting
130 Dipole element 131 Feed point
133 Element 135 Balun
137 ... fixed member 138 ... fastened member
139 Feeder 150 Omni Antenna Element
170 Feeder 171 External Feed Point

Claims (11)

Reflector;
Two dipole elements having a horizontal polarization characteristic formed on the reflecting plate so as to face each other and having radiated radio waves out of phase with each other; And
Omni antenna elements having a vertical polarization characteristic in which two are formed facing each other on the reflection plate in an orthogonal direction between the dipole elements, and radiating radio waves are in phase with each other;
Dual polarized bidirectional antenna comprising a.
The method of claim 1,
An omni-feeding unit having a same length for feeding each of the omni antenna elements; And
Further comprising a dipole feeding portion of the same length for feeding each of the dipole elements,
Each of the dipole elements is composed of two elements on the left and right sides with respect to the direction viewed from the opposite element, and a feed point is formed on the same element side of the two elements.
The method of claim 1,
An omni-feeding unit having a same length for feeding each of the omni antenna elements; And
Each of the dipole elements further includes a dipole feeding part having a different length for feeding signals that are out of phase with each other,
Each of the dipole elements is composed of two elements on the left and right sides with respect to the direction viewed from the opposite element, and a feed point is formed on a different element side of the two elements.
The method of claim 1,
And a center between the omni antenna elements is the same as a center between the dipole elements.
The method according to any one of claims 1 to 4,
And the dipole element is bent so that the surface of the element is parallel to the reflecting plate.
The method according to any one of claims 1 to 4,
The dipole element,
A fixing member fastened on the reflecting plate;
A balun extending in an upward direction of the upper surface of the reflecting plate in a state separated into two from the fixing member; And
Two elements extending horizontally and opposite to each other at the end of each balun;
Dual polarized bidirectional antenna comprising a.
The method according to claim 6,
And the balun is bent such that the face of the element is parallel to the reflector.
The method according to any one of claims 1 to 4,
And said omni antenna element comprises an element fastened vertically on said reflector.
The method according to any one of claims 1 to 4,
And a distance between the dipole elements and a distance between the omni antenna elements is 0.3 lambda or more within a 0.8 lambda range of each frequency wavelength.
The method according to any one of claims 1 to 4,
The reflecting plate is a dual polarized bidirectional antenna, characterized in that the end portion is cut in the radial direction of the dipole element.
The method of claim 10,
The reflector is a dual polarized bidirectional antenna, characterized in that the installation is in close contact with one of the straight wall, ceiling, floor.

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