KR102093204B1 - Wideband mimo antenna having isolation improved structure - Google Patents

Abstract

The present invention provides a wideband MIMO antenna, which comprises: a substrate; a plurality of power supply lines formed in a predetermined pattern on an upper surface of the substrate and transmitting a feeding signal applied through a feeding port; a plurality of grounding patterns formed on an upper surface of the substrate so as to extend in both directions of each of corresponding feeding lines of the plurality of feeding lines, and forming a CPW structure with the corresponding feeding lines; a plurality of radiating elements arranged on both sides of the substrate to receive the feed signal from the corresponding feed line of the plurality of feed lines; and a parasitic patch formed in accordance with a predetermined pattern on the lower surface of the substrate. Therefore, the isolation between a plurality of radiation elements is improved so as to have a low profile.

Description

Wideband MIMO antenna with improved isolation structure {WIDEBAND MIMO ANTENNA HAVING ISOLATION IMPROVED STRUCTURE}

The present invention relates to a wideband MIMO antenna, and to a wideband MIMO antenna having a low profile and high isolation between radiating elements.

Mobile communication systems are developing very rapidly. In the early stages of mobile communication, communication inside the building was provided through an outdoor repeater. In this case, it was difficult to provide quality service due to high signal loss caused by the walls of the building. In particular, various and many studies have been conducted to solve the high traffic capacity problem that occurs in indoor communication environments such as shopping centers, buildings, and stadiums.

As the number of mobile communication subscribers has increased rapidly, communication quality in the building continues to be a problem, which can solve the high traffic capacity problem in the indoor communication environment, and is one of the ways to effectively remove the communication shadow area. The installation of distributed antenna systems is rapidly increasing.

The distributed antenna system is a system that receives a signal through a large, high-gain antenna installed outside, distributes the signal, and re-transmits it through a small antenna installed at regular intervals throughout the building.

One of the advantages of a distributed antenna system is that it is capable of accommodating multiple frequencies with one repeater device that constitutes the system. That is, the existing 2G and 3G communication methods such as GSM, CDMA, and WCDMA methods, and all existing communication methods such as 4G LTE communication and WiFi can be covered. Another advantage is that by distributing and installing a small antenna inside the building, it is possible to effectively solve the communication shadow area and solve the high traffic capacity problem.

Therefore, the antenna mounted on the distributed antenna system can also cover the frequency ranges of all of the existing 2nd and 3rd generation communication methods such as GSM, CDMA, and WCDMA, and 4th LTE communication and WiFi. There is a need for an antenna having an omni-directional radiation pattern that has a wide communication bandwidth and can secure a wide communication range by efficiently radiating in all directions in the entire communication band.

On the other hand, in a distributed antenna system, since the system is equipped with MIMO (Multi Input Multi Output) technology for faster communication speed, the antenna also includes a plurality of radiating elements mounted on one antenna, and thus a MIMO antenna capable of performing multiple input / output operations. Is required.

Here, in order to mount a plurality of radiating elements on one antenna, it is important to secure a sufficient distance between the two radiating elements to ensure isolation between radiating elements. However, since the antenna is mounted indoors, it has to be designed in a compact and thin form. For this reason, there is a need for an antenna design technology that can mount a plurality of radiating elements on one antenna and ensure isolation even when the distance between radiating elements is close.

Korean Open Patent No. 10-2007-0020279 (published on February 20, 2007)

An object of the present invention is to provide a wideband MIMO antenna that has a low profile and can be easily installed indoors.

Another object of the present invention is applicable to a MIMO system, and to provide a wideband MIMO antenna having high isolation between radiating elements.

Another object of the present invention is to provide a wideband MIMO antenna capable of efficiently radiating in all directions in all communication bands.

Broadband MIMO antenna according to an embodiment of the present invention for achieving the above object is a substrate; A plurality of power supply lines formed in a predetermined pattern on the upper surface of the substrate and transmitting a power supply signal applied through the power supply port; A plurality of ground patterns formed on the upper surface of the substrate so as to extend in both directions of each of the corresponding feeding lines among the plurality of feeding lines, thereby forming a CPW structure with the corresponding feeding lines; A plurality of radiating elements disposed on both sides of the substrate and receiving the feed signal from a corresponding feed line among the plurality of feed lines; And a parasitic patch formed according to a pattern defined on the lower surface of the substrate. It includes.

The plurality of radiating elements are formed in an extended form according to a predetermined pattern based on the feed line on both sides of the substrate, and may have an asymmetric size in the front-rear direction.

The parasitic patch may be formed so as not to overlap with the area where the feeding line is disposed, and an area of the plurality of radiating elements having an asymmetric size based on the feeding line may be formed in a large direction.

The parasitic patch may be formed to have an area overlapping each of the plurality of ground patterns formed on the upper surface of the substrate.

The plurality of radiating elements may be connected to each other by a connecting element having a half-wavelength length of the feeding signal, and the connecting element is one end in a direction in which the area of the plurality of radiating elements having an asymmetric size with respect to the feeding line is large. Can be connected to each.

The plurality of radiating elements are formed of an aluminum sheet and are partially overlapped on both sides of the substrate, and the feeding line is formed at one end so that the radiating elements overlap the region where the substrate overlaps, and when the feeding signal is applied, the It can be coupled with a radiating element.

Broadband MIMO antenna according to another embodiment of the present invention for achieving the above object is a substrate; A plurality of power supply lines formed in a predetermined pattern on the upper surface of the substrate and transmitting a power supply signal applied through the power supply port; A plurality of ground patterns formed on the upper surface of the substrate to extend in both directions of each of the corresponding feeding lines among the plurality of feeding lines to form a CPW structure with the feeding lines; A plurality of radiating elements disposed on both sides of the substrate and receiving the feed signal from a corresponding feed line among the plurality of feed lines; And a connecting element having a half-wavelength length of the feeding signal and connecting the plurality of radiating elements to each other. It includes.

Accordingly, the wideband MIMO antenna according to an embodiment of the present invention not only has high isolation between a plurality of radiating elements, but also has a small and thin low profile, so it is easy to be mounted indoors and efficiently radiates in all directions in all communication bands. can do.

1 shows the appearance of a wideband MIMO antenna according to an embodiment of the present invention.
2 shows the structure of a wideband MIMO antenna according to an embodiment of the present invention.
3 to 6 show detailed structures of each of the components of the broadband MIMO antenna of FIG. 2.
7 is a view for explaining the function of the connection element of FIG.
8 and 9 show reflection loss characteristics of a wideband MIMO antenna according to the present embodiment.
10 and 11 show isolation characteristics between two antennas of the wideband MIMO antenna device according to the present embodiment.
12 and 13 are diagrams for explaining the level of impedance matching depending on whether a parasitic patch is formed.
14 to 19 are diagrams for explaining the impedance matching level according to the pattern of the parasitic patch.
20 and 21 are diagrams for explaining the isolation characteristics depending on whether a connection element is formed.
22 and 23 are views for explaining the isolation characteristics according to the pattern of the connecting element.
24 shows a radiation pattern for each operating frequency of the broadband MIMO antenna device according to the present embodiment.

In order to fully understand the present invention, the operational advantages of the present invention, and the objects achieved by the practice of the present invention, reference should be made to the accompanying drawings and the contents described in the accompanying drawings, which illustrate preferred embodiments of the present invention.

Hereinafter, the present invention will be described in detail by explaining preferred embodiments of the present invention with reference to the accompanying drawings. However, the present invention may be implemented in various different forms, and is not limited to the described embodiments. In addition, in order to clearly describe the present invention, parts irrelevant to the description are omitted, and the same reference numerals in the drawings indicate the same members.

Throughout the specification, when a part “includes” a certain component, this means that other components may be further included, rather than excluding other components, unless otherwise specified. In addition, terms such as "... unit", "... group", "module", and "block" described in the specification mean a unit that processes at least one function or operation, which is hardware or software or hardware. And software.

1 shows the appearance of a wideband MIMO antenna according to an embodiment of the present invention.

Referring to FIG. 1, the outer shape of the broadband MIMO antenna of the present embodiment is composed of an upper case 110 and a lower case 120, and thus may be implemented as a disk.

In addition, two feeding ports 130 may be inserted into the lower case 120 to supply a feeding signal to a wideband MIMO antenna. As illustrated in FIG. 1, the two feeding ports 130 are inserted separately and may be inserted into the center of the circular lower case 120. The insertion position of the feeding port 130 can be variously adjusted. The feeding port 130 may be implemented as, for example, a coaxial cable.

2 shows a structure of a wideband MIMO antenna according to an embodiment of the present invention, and FIGS. 3 to 6 show a detailed structure of each component of the wideband MIMO antenna.

In Fig. 2, (a) and (b) show the upper and lower surfaces of the wideband MIMO antenna according to the present embodiment, Fig. 3 shows the detailed structure of the feeding line and the feeding part of the wideband MIMO antenna, and Fig. 4 shows the feeding The detailed structure of the coupling region between the line and the radiating element is shown. And in Figure 5 (a) shows the detailed structure of the feed line and the ground pattern formed on the upper surface of the substrate, (b) shows the detailed structure of the parasitic patch formed on the lower surface of the substrate. 6 shows the detailed structure of the radiating element.

The broadband MIMO antenna according to the present embodiment includes a substrate 210, a radiating element 220, a feeding line 230, a ground pattern 240, a feeding unit 250, and a parasitic patch 260.

The wideband MIMO antenna according to the present embodiment is an antenna for a MIMO system, including a plurality of radiating elements 220 spaced apart from each other, and corresponding to a plurality of radiating elements 220, a plurality of feeding lines 230 and a plurality of It may include a ground pattern 240 and a plurality of feeder 250. In this embodiment, as an example, a wideband MIMO antenna includes two radiating elements 220, and correspondingly, two feeding lines 230, two ground patterns 240, and two feeding parts 250 are provided. .

Since the two radiating elements 220, the two feeding lines 230, the two ground patterns 240, and the two feeding parts 250 are symmetrically arranged on both sides of the substrate 210, the broadband according to the present embodiment The omni-directional antenna can be regarded as including two antenna units ANT1 and ANT2 including a radiating element 220, a feeding line 230, a ground pattern 240, and a feeding unit 250, respectively.

2 and 6, the two radiating elements 220 are disposed in both directions on the upper surface of the substrate 210. Here, the two radiating elements 220 may be arranged such that some regions overlap with some corresponding regions on the substrate 210. When the radiating element 220 is not entirely disposed on the substrate 210 but only a part is disposed in a corresponding region of the substrate 210, the substrate 210 has a size independent of the size of the radiating element 220. Can have That is, since the two radiating elements 220 need not be disposed on the substrate 210, the size of the substrate 210 can be greatly reduced.

This makes it possible to reduce the size of an expensive low-loss substrate that is mainly used in high-performance antennas, thereby reducing the manufacturing cost of a wideband MIMO antenna.

And each of the two radiating elements 220 is formed in a form that extends according to a predetermined pattern from a position overlapping the substrate. The two radiating elements 220 are disposed on both sides of the substrate, and are formed in a symmetrical shape with respect to the substrate.

In particular, each of the two radiating elements 220 has an asymmetric size in front and rear with respect to the feed line 230 formed on the substrate 210.

Referring to FIG. 2, it can be seen that the radiating element 220 is formed to have a larger area expanded in the front than an expanded area in the rear. Here, the forward direction, the rear direction, and both sides are independent of the function of the broadband omni-directional antenna of this embodiment in a designated direction for convenience of explanation.

The two radiating elements 220 may be implemented with various conductor materials, for example, an aluminum sheet. In addition, each of the two radiating elements 220 is disposed to be in close contact with a corresponding region of the feed line 230 formed on the upper surface of the substrate 210. This is to ensure that a power supply signal applied through the power supply line 230 can be transmitted using a coupling phenomenon. However, the two radiating elements 220 may be configured to be directly electrically connected to the feeding line 230 with the substrate 210.

In particular, in the present embodiment, the two radiating elements 220 may be connected to each other by connecting elements 221 formed in a predetermined pattern. Here, the connecting element 221 may be connected to two radiating elements 220 at one end in a direction (in this case, omni-directional) in which the area of the radiating element 220 having an asymmetric size in the front and rear is large.

The connection element 221 may be formed in a known pattern having a length of λ / 2, for example. In addition, the two radiating elements 220 and the connecting elements 221 are not independently manufactured, but may be integrally manufactured with the same conductor as illustrated in FIG. 6.

A detailed description of the function of the connecting element 221 will be described later.

Meanwhile, referring to FIGS. 2 to 4, the two feeding lines 230 are connected between corresponding feeding elements of the two feeding portions 250 and corresponding radiating elements of the two radiating elements 220, respectively. The feeding line 230 receives the feeding signal through the corresponding feeding unit 250 and transmits the feeding signal to the corresponding radiating element 220. At this time, the feed line 230 may transmit a feed signal to the radiating element 220 using a coupling phenomenon as described above. As shown in FIG. 4, so that the coupling phenomenon with the radiating element 220 is easily generated, the feed line 230 is a pattern corresponding to the overlapping region where the radiating element 220 overlaps on the substrate 210. Can be formed. That is, a region overlapping the radiating element 220 in the feed line 230 may be formed as a coupling region 410 coupled to the radiating element 220.

In addition, each of the two feeding lines 230 forms a coplanar waveguide (CPW) structure together with a corresponding grounding pattern among the two grounding patterns 240 to radiate elements 220 corresponding to the feeding signal transmitted from the feeding unit 250. ).

The two ground patterns 240 are formed on the upper surface of the substrate 210 so as to extend in both directions (front-rear direction on the drawing) of the corresponding power supply line among the two power supply lines 230, and thus, the corresponding A CPW structure may be formed together with the feed line 230. In addition, the two ground patterns 240 are respectively connected to the corresponding power supply unit 250 among the two power supply units 250 to be grounded.

The two power feeding parts 250 are formed separately at predetermined positions of the substrate 210. Here, the two feeding parts 250 are illustrated as being formed adjacent to each other in the central region of the substrate 210, but are not limited thereto.

Each of the two feeding units 250 transmits a feeding signal applied through the feeding port 130 to the feeding line 230 and applies ground power to the ground pattern 240. Each of the two feeding parts 250 may be formed through the substrate 210, but is not limited thereto.

Meanwhile, referring to FIGS. 2 and 5, in the broadband omni-directional antenna according to the present embodiment, a parasitic patch 260 having a predetermined pattern may be further formed on the lower surface of the substrate 210. The parasitic patch 260 may be formed to partially overlap two ground patterns 240 formed on the upper surface of the substrate 210.

That is, some regions of the parasitic patch 260 are formed to be spaced apart from the ground pattern 240 with the substrate 210 therebetween. Therefore, the coupling phenomenon is induced, and thereby, the radiating element 220 and the feeding line 230 can be impedance matched in a wide band, and electromagnetic energy can be generated in a quasi omni-directional pattern. . From a circuit point of view, a parasitic patch may be interpreted as an inductance component, and a region where the ground pattern 240 and the parasitic patch 260 overlap may be interpreted as a capacitance component. Therefore, the area where the ground pattern 240 and the parasitic patch 260 overlap may be interpreted as a parallel inductor and capacitor impedance matching circuit. And the parasitic patch 260 in the non-overlapping region may be interpreted as a series inductor impedance matching circuit.

In particular, in this embodiment, the parasitic patch 260 is formed so as not to overlap with the area where the power supply line 230 is disposed. In addition, it is formed only in the forward direction based on the feed line 230. That is, the sizes of the plurality of radiating elements having asymmetric sizes in the front-rear direction are formed in a large direction. The detailed description of the parasitic patch 260 will be described later.

7 is a view for explaining the function of the connection element of FIG.

In the MIMO system, the plurality of radiating elements 220 should be spaced apart at a predetermined distance (λ / 4) or more. However, this is a factor that makes it difficult to reduce the size of a broadband MIMO antenna. That is, it makes it difficult for a wideband MIMO antenna to have a low profile.

Accordingly, in order to further reduce the size of the wideband MIMO antenna, even if the spacing of the plurality of radiating elements 220 is less than a predetermined spacing, it should be possible to not affect each other. That is, the isolation between the radiating elements 220 should be improved.

And in order to improve the isolation between the radiating elements 220, in this embodiment, the two radiating elements 220 are connected to each other using a connecting element 221 having a length of λ / 2. The two radiating elements 220 by the connecting element 221 having a length of λ / 2 may cause an effect similar to that in which the current paths are electrically blocked from each other.

In FIG. 7, that is, even if a plurality of radiating elements 220 are arranged to be spaced apart at a predetermined distance (λ / 4) or less, they do not affect each other. When the feeding signal is applied to one radiating element 220 through the feeding line 230, the connecting element 221 reduces the amount of current induced in the remaining feeding line and the current concentrated in the remaining ground pattern 240. I can do it.

As a result, the gap between the plurality of radiating elements 220 can be reduced, so that the wideband MIMO antenna can be implemented with a small, low profile.

7 (a) and (b) both represent a case in which a feed signal is supplied to and radiated to the radiating element 220 of the second antenna ANT2, and (a) is when the connecting element 221 is not formed. And (b) shows a case in which two radiating elements 220 are connected by a connecting element 221.

When (a) and (b) are compared, in (a), when a feed signal is applied to the radiating element 220 through the second antenna ANT2 feed line 230, the first antenna ANT1 feed line It can be seen that the current is also induced at 230. In addition, a concentrated current is generated in some areas of the ground pattern 240 of the first antenna ANT1. However, when the two radiating elements 220 are connected to the connecting element 221, the connecting element 221 causes an effect similar to the electromagnetic path being electromagnetically blocked, so as shown in (b), the power feeding The current induced in the line 230 may be reduced. In addition, it is possible to reduce the concentrated current that may be induced in some locations of the ground pattern 240.

Due to this, even when the two radiating elements 220 are disposed close to each other, when radiating a signal from one antenna, it is possible to reduce the current induced to the other radiating elements. That is, the isolation between the two radiating elements 220 can be improved.

8 and 9 show the return loss characteristics of the wideband MIMO antenna according to the present embodiment, FIG. 8 shows the simulation result, and FIG. 9 shows the actual measurement result. 8 and 9, (a) represents the return loss characteristic of the first antenna ANT1, and (b) represents the return loss characteristic of the second antenna ANT2.

8 and 9, the wideband MIMO antenna according to the present embodiment is a voltage standing wave ratio (Voltage Standing Wave Ratio: below) in the operating frequency band of 698MHz ~ 6GHz, which is a communication band of various communication schemes not only in simulation but also in actual measurement results. VSWR) value is 2: 1 or less, and it can be seen that it has a very wide operating bandwidth while satisfactorily satisfying the return loss characteristic for operating as an antenna.

This means that the wideband MIMO antenna according to the present embodiment can cope with the frequency ranges of the existing 2nd and 3rd generation communication methods such as GSM, CDMA, and WCDMA methods, and all communication methods provided with 4G LTE communication methods and WiFi. it means.

10 and 11 show the isolation characteristics between the two antennas of the broadband MIMO antenna device according to the present embodiment, similar to FIGS. 8 and 9, FIG. 10 shows simulation results, and FIG. 11 shows actual measurement results .

10 and 11, the high-gain omni-directional antenna according to the embodiment of the present invention has an S21 value of -15 dB or less in an operating frequency band of 698 MHz to 960 MHz, which is a communication band, and an operating frequency band of 1710 MHz to 6 GHz. It can be seen that the S21 value is less than -20 dB, and has very good isolation characteristics at a wide operating bandwidth.

12 and 13 are diagrams for explaining the level of impedance matching depending on whether a parasitic patch is formed.

12 (a) shows the case where the parasitic patch 260 is formed on the lower surface of the substrate 210, and (b) shows the case where the parasitic patch 260 is not formed. And (a) and (b) of Figure 13 shows the return loss characteristics for the antenna of Figure 12 (a) and (b), respectively.

Referring to (a) and (b) of FIG. 13, when the parasitic patch 260 is not formed in the antenna, as shown in FIG. 12 (b), it is relatively low compared to the case where the parasitic patch 260 is formed. It can be seen that the VSWR value at 698 MHz, which is the frequency communication band, was very high at 4.1: 1. And it can be seen that it has increased to 2.2: 1 from the middle frequency communication band 1710MHz. That is, when the parasitic patch 260 is not present, it is difficult to achieve broadband impedance matching because the VSWR value is high.

14 to 19 are diagrams for explaining the impedance matching level according to the pattern of the parasitic patch.

14 and 15 are diagrams for explaining the level of impedance matching depending on whether the parasitic patch 260 overlaps the feed line 230.

14 (a) shows a case in which the parasitic patch 260 is formed in a pattern overlapping with the feeding line 230, and (b) does not overlap with the feeding line 230 and is forward based on the feeding line 230. It represents a case formed only with. And (a) and (b) of Figure 15 shows the return loss characteristics for the antenna of Figure 14 (a) and (b), respectively.

As shown in (a) and (b) of Figure 15, when the parasitic patch 260 is formed overlapping the feed line 230, compared to the case formed only in the front, in the low frequency communication band 698MHz and 960MHz It can be seen that the VSWR values of have been increased to 2.7 and 2.6, respectively. In addition, it can be seen that the frequency has been increased to 2.4: 1 from the 1710MHz intermediate frequency communication band. Therefore, when the parasitic patch 260 is formed in a pattern overlapping the feed line 230, it is difficult to achieve broadband impedance matching.

16 and 17 are diagrams for explaining the impedance matching level when a plurality of parasitic patches 260 are disposed.

In FIG. 16 (a), the parasitic patch 260 is not overlapped with the feed line 230, but two are formed in the forward and rear directions, whereas in (b) only one is formed in the forward direction.

In FIG. 17, the isolation characteristic (green line) between the return loss characteristic (red line) and the first and second antenna units ANT1 and ANT2 is also shown. When (a) and (b) of FIG. 17 are compared, as shown in FIG. 16 (a), when the parasitic patch 260 is additionally formed in the rear direction, the return loss value in the 698 MHz to 6 GHz band is − It can be seen that the impedance matching was improved to 10 dB or less. However, the isolation characteristic is -7.7 dB at 698 MHz, which can be confirmed to be very deteriorated compared to -11 dB when the parasitic patch 260 is not present in the opposite direction. Therefore, the parasitic patch 260 for broadband impedance matching is preferably applied only to one side so as not to degrade the isolation characteristics of the two antennas.

18 and 19 are diagrams for explaining the impedance matching level according to the placement position of the parasitic patch 260.

As described above, the parasitic patch 260 is preferably disposed only on one side rather than on the basis of the feed line 230 in order to improve the isolation between the first and second antenna portions ANT1 and ANT2. . Accordingly, FIGS. 18A and 18B show the case where the parasitic patch 260 is disposed in the front direction and the case in the rear direction, respectively.

In FIG. 19, the isolation loss characteristic and the isolation characteristic between the first and second antenna units ANT1 and ANT2 are also shown. When (a) and (b) of FIG. 19 are compared, when the position of the parasitic patch 260 is formed in the rear direction as shown in (b), the return loss in the 698 MHz band compared to the case formed in the forward direction as shown in (a) It can be seen that the impedance matching was deteriorated with a value of -5.6dB and a return loss value of -4.0dB in the 720MHz band and a return loss value of -9.7dB in the 1710MHz band. In addition, it can be seen that even in the isolation characteristic, the deterioration was obtained in comparison with the case of (a) at -98dB at 698MHz and -10.9dB at 960MHz. Therefore, it can be seen that the parasitic patch 260 for broadband impedance matching has a broadband impedance matching effect without deterioration of isolation characteristics only when the radiating element 220 is formed to be expanded and formed.

20 and 21 are diagrams for explaining the isolation characteristics depending on whether a connection element is formed.

In (a) of FIG. 20, one end in all directions of the two radiating elements 220 is connected by the connecting element 221, whereas in (b) the connecting element 221 is not formed and is independently arranged. In Fig. 21, (a) shows the isolation when the connection element 221 is formed according to (a) of Fig. 20, and (b) shows the isolation when the connection path is not formed according to Fig. 20 (b). Shows.

When (a) and (b) of FIG. 21 are compared, in the case of (b) without the connection element 221, the S21 value is -11 dB to -13 dB or less in the operating frequency band of 698 MHz to 960 MHz, which is a low frequency communication band. , When the connection element 221 is formed, it can be seen that the isolation value of S21 is -17dB to -21dB, which greatly improves isolation.

22 and 23 are views for explaining the isolation characteristics according to the pattern of the connecting element.

In Figure 22 (a), the connecting element 221 is connected to one end in the forward direction of the two radiating elements 220, while in (b), the connecting element 221 is connected to one end in the rear direction of the two radiating elements 220. Connected to form different patterns.

22 (a), when the connecting element 221 is connected in all directions of the radiating element 220, the S21 value is -17 dB to -21 dB or less in the operating frequency band of 698 MHz to 960 MHz, which is a low frequency communication band. On the other hand, as shown in (b), when the connecting element 221 is connected in the rear direction, the S21 value is deteriorated to -8dB to -15dB.

Therefore, it can be seen that the isolation factor 221 is improved only when the connecting element 221 is connected to the radiating elements 220 in all directions in which the size of the radiating element 220 is expanded.

24 shows a radiation pattern for each operating frequency of the broadband MIMO antenna device according to the present embodiment, and shows a 2D radiation pattern measured in the Azimuth Plane.

24, (a) to (c) show radiation patterns at 698 MHz, 1710 MHz, and 2.7 GHz operating frequencies, respectively. And (a) to (c) in each of the first antenna portion (ANT1) and the second antenna portion (ANT2) of the independent radiation pattern and the first and second antenna portions (ANT1, ANT2) when radiating simultaneously The patterns are shown together.

As shown in FIG. 24, the wideband MIMO antenna according to the present embodiment does not have a perfect omni-directional pattern when the first antenna unit ANT1 and the second antenna unit ANT2 operate alone, but the first antenna unit It can be seen that when the (ANT1) and the second antenna unit (ANT2) operate at the same time, they have a quasi-omni-directional radiation pattern.

Although the present invention has been described with reference to the embodiments shown in the drawings, these are merely exemplary, and those skilled in the art will understand that various modifications and other equivalent embodiments are possible therefrom.

Therefore, the true technical protection scope of the present invention should be defined by the technical spirit of the appended claims.

110: upper case 120: lower case
130: power supply port 210: board
220: radiating element 221: connecting element
230: feed line 240: ground pattern
250: feeder 260: parasitic patch
410: coupling area

Claims (12)

Board;
A plurality of power supply lines formed in a predetermined pattern on the upper surface of the substrate and transmitting a power supply signal applied through the power supply port;
A plurality of ground patterns formed on the upper surface of the substrate so as to extend in both directions of each of the corresponding feeding lines among the plurality of feeding lines, thereby forming a CPW structure with a corresponding feeding line;
A plurality of radiating elements disposed on both sides of the substrate and overlapping the substrate, and receiving the feed signal from a corresponding feed line among the plurality of feed lines; And
A parasitic patch formed according to a pattern defined on the lower surface of the substrate; Including,
The plurality of radiating elements
It is formed in a form that extends in accordance with a predetermined pattern based on the feed line on both sides of the substrate, has an asymmetric size in the front-rear direction,
The parasitic patch is formed so as not to overlap the region where the power supply line is disposed and the region where the plurality of radiating elements are disposed,
The parasitic patch is formed in a direction in which an area of the plurality of radiating elements having an asymmetric size based on the feed line is large, and has an area overlapped with each of the plurality of ground patterns formed on an upper surface of the substrate,
The plurality of radiating elements are connected to each other by a connecting element having a half-wavelength length of the feeding signal, and the connecting elements are connected to one end of a direction in which the area of the plurality of radiating elements having an asymmetric size with respect to the feeding line is large. Broadband MIMO antennas connected to each other.

delete delete delete delete delete delete The method of claim 1, wherein the plurality of radiating elements
A broadband MIMO antenna implemented with an aluminum sheet and partially overlapped on both sides of the substrate. 9. The feeding line of claim 8, wherein the feeding line
A broadband MIMO antenna having one end formed so that the radiating element overlaps an area overlapping the substrate, and coupled with the radiating element when the feed signal is applied. delete delete delete

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