KR20090050566A - Mimo system installed in vehicle - Google Patents

Abstract

The present invention provides a MIMO system installed in a vehicle, comprising: two or more antennas disposed on a glass plate; And an antenna signal end of an RF circuit electrically connected to the feed terminal of the antenna, wherein the antennas are arranged such that the points at which each electric field is maximum are spaced apart from each other at maximum.

The present invention as described above provides a MIMO system installed in a vehicle to enable the use of mobile services in the vehicle by enabling a large amount of information transmission using the next generation 4G communication protocol.

MIMO, antenna, vehicle

Description

MIMO system installed in a vehicle {MIMO SYSTEM INSTALLED IN VEHICLE}

The present invention relates to a MIMO system installed in a vehicle to enable a mobile service in a vehicle by enabling a large amount of information transmission using a next generation 4G communication protocol.

In the next generation 4G communication, with the wide spread of wireless communication terminals and the rapid development of the telecommunication field, various multimedia such as video, music, and games have been attempted. Since multimedia containing video and audio has a large amount of information, a high data rate must be ensured in order to provide multimedia smoothly through a MIMO system.

As a system for high speed data transfer, a multiple-input multiple-output (MIMO) system is known. The MIMO system has a plurality of antennas, which enable high speed data transmission by receiving different signals.

The biggest impact on the performance of a MIMO system is interference between antennas arranged in close proximity to each other for miniaturization. Antennas that transmit and receive electromagnetic waves generate a current in the ground plane, which can cause changes in the characteristics of other antennas by electromagnetic coupling with other antennas arranged on the same ground plane. In addition, there may be interference due to electromagnetic coupling between antennas arranged in close proximity.

To improve the isolation between antennas for MIMO systems, each antenna can exhibit its designed characteristics by using circularly polarized antennas in different directions to prevent electromagnetic coupling between the antennas, Techniques for forming slits one quarter the length of the wavelength are known.

However, the directional circularly polarized antenna has a problem in that path loss is higher than that of an omnidirectional dipole antenna when used in a MIMO system.

Since the inverted F antenna is directly connected to the ground plane, current easily flows from the antenna to the ground plane when transmitting and receiving electromagnetic waves, and when used in a MIMO system, greatly affects other antennas arranged on the same ground plane. In order to avoid such interference between the antennas, by forming slits 1/4 times the wavelength of the antenna with respect to the resonance frequency of the antenna in the ground plane between the antennas, it is possible to improve the isolation between the antennas. However, such processing of the ground plane places a limitation on the space in which other elements can be disposed, and thus has a problem against miniaturization of the system.

On the other hand, an unbalanced feeding structure in which an inner pin of the coaxial cable is connected to one end of the antenna and an outer coaxial cable is connected to the other end of the antenna has a small amount of unbalance on the ground plane. It is known to generate an unbalanced current flow. However, there is a problem in that the folded loop antenna of the unbalanced feed structure is also bulky due to the complexity of the feed structure, and thus the miniaturization of the system.

The present invention devised to solve the above problems is to provide a MIMO system installed in a vehicle to enable the use of mobile services in the vehicle by enabling large-scale information transmission using a next-generation 4G communication protocol. .

The present invention for achieving the above object is, MIMO system installed in a vehicle, two or more antennas disposed on the glass plate; And an antenna signal end of an RF circuit electrically connected to the feed terminal of the antenna, wherein the antennas are arranged such that the points at which each electric field is maximum are spaced apart from each other at maximum.

Preferably, the number of antennas is 4, and the first antenna and the second antenna are arranged to be spaced apart from the upper edge of the glass plate by a predetermined distance, and the third and fourth antennas are spaced apart from the lower edge of the glass plate by a predetermined distance. It may be arranged to.

In addition, the antenna may have an electrical length of any one of 3/8 times length, 5/8 times length, and 3/4 times length of the wavelength with respect to the resonance frequency.

In addition, any two antennas of the above antennas may be arranged such that each arrangement direction is perpendicular to each other.

In addition, the antennas may be disposed along an edge of the glass plate.

In addition, the antenna may be mounted in a case of a conductor, and the case may operate as a ground plane. More preferably, the case may be detachable from the glass plate.

In addition, the MIMO system may be formed in the rear window, the front window, the rearview mirror or the rearview mirror of the vehicle.

As described above, the present invention provides an in-vehicle MIMO system that is installed in a vehicle to enable large-scale information transmission using a next-generation 4G communication protocol to enable mobile services in the vehicle.

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

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like reference numerals in the drawings denote like elements.

1 is a perspective view of an inverted L-type antenna included in a MIMO system installed in a vehicle according to an embodiment of the present invention. FIG. 1B is a perspective view of the dotted arrow 260 shown in FIG. 1A.

As shown in FIG. 1, the inverted L-type antenna 200 included in the MIMO wireless communication terminal according to the present embodiment reduces the size of the antenna and the support of the radiator 220 and the radiator 220 that transmit and receive electromagnetic waves. And a dielectric 240 that can be made.

The radiator 220 of the inverted L-type antenna is electrically connected to the antenna signal terminal 140 of the RF circuit through the feed terminal 222 formed at one end thereof, but is not directly connected to the ground plane (not shown). Preferably, the inverted L-type antenna 200 may be mounted on the case of the conductor, and the case of the conductor may be used as the ground plane.

Meanwhile, a stub 224 may be formed at one end of the radiator 220, and the radiation characteristics of the radiator 220 may be adjusted by changing the length or width of the stub 224. The radiator 220 transmits and receives electromagnetic waves by resonating with an electromagnetic wave of a specific frequency according to its shape, wherein the magnitude of the electric field formed in the radiator 220 is the case of the inverted L-type antenna 200 used in the present embodiment. Maximum at the open end 226 of the radiator 220.

2 and 3 are a plan view and a perspective view briefly showing the installation state of the MIMO system according to the present embodiment, respectively.

As shown in Figures 2 and 3, the MIMO system according to the present embodiment is installed in the vehicle to enable the transmission of large amounts of information. In more detail, the MIMO system of the present invention is formed at four corners in which the dotted ellipse is formed in the rear window of the vehicle as illustrated in FIG. 4, or the dotted ellipse is formed in the rearview mirror as illustrated in FIG. 5. It may be formed at the corner. However, the present invention is not limited thereto, and may be formed at four corners of the windshield of the vehicle or at four corners of the rearview mirror.

Among the four inverted L-shaped antennas 200 included in the MIMO system installed in the vehicle, the first antenna and the second antenna are disposed to be spaced apart a predetermined distance from the upper corner of the rectangular glass plate 100, and the third antenna Is disposed at the lower left corner of the glass plate 100, and the fourth antenna is disposed at the lower right corner of the glass plate 100. As such, the four inverted L-type antennas 200 may be spaced apart from each other as much as possible to minimize mutual interference.

The feed terminals 222 of the four inverted L-type antennas 200 are electrically connected to the antenna signal terminal 140 of the RF circuit, respectively, and form a loop shape as a whole.

As described above, the ground plane may be formed of a conductor case of an inverted L-type antenna formed at four corners of the glass plate 100, and the conductor case may be detachably formed to adjust the position of the antenna on the glass plate 100. You can change it or remove the antenna. In addition, the inverted L-type antenna 200 may be formed by using FPCB in various designs.

The radiator 220 of the inverted L-type antenna 200 included in the MIMO system according to the present embodiment has a large inductance pattern, and a capacitance component induced by the distance between the inverted L-type antenna 200 and the ground plane. Affects the resonant frequency and return loss of the inverted L-type antenna 200. Therefore, by adjusting the distance between the inverted L-type antenna 200 and the ground plane, the resonance frequency and the reflection loss of the inverted L-type antenna 200 can be adjusted.

Since the inverted L-type antenna 200 is not directly connected to the ground plane, the current generated by the inverted L-type antenna 200 at the ground plane during transmission and reception of electromagnetic waves flows from the inverted F-type antenna connected to the ground plane to the ground plane. The lifting current is considerably weaker than the current. Therefore, the effect that the current generated by the inverted L-type antenna 200 on the ground plane may have on other antennas by electromagnetic coupling with other antennas is weak.

The electrical length of the inverted L-shaped antenna 200 may be one quarter the length of the wavelength relative to its resonance frequency. However, since this is a length sufficient to obtain an image effect on the ground plane, a strong current is induced in the ground plane as compared with an inverted L-type antenna having a longer length when transmitting and receiving electromagnetic waves. Therefore, in order to minimize the current generated by the inverted L-type antenna 200 to the ground plane and to further improve the isolation between the antennas for the MIMO system, the electrical length of the inverted L-type antenna 200 is changed to the wavelength of its resonance frequency. It is preferred to form 3/8 times longer, 5/8 times longer or 3/4 times longer than 1/4 times the length. This increases the distance from the ground plane to the open end 226 of the radiator 220 which is the point where the electric field is maximum, which also contributes to the improvement of the isolation between the antennas. In addition, it has the advantage of easy impedance matching with a 50Ω circuit compared to an inverted L-type antenna having a length 1/2 times the wavelength with respect to the resonance frequency, which is difficult to match impedance due to large resistance and reactance.

On the other hand, the inverted L-shaped antennas 200 arranged on the same glass plate 100 may be affected by the electromagnetic coupling between each other, and the main influence on the interference is the radiator which is the point where the electric field of each antenna is maximum ( 220 is an open end 226. Thus, as shown in FIGS. 2 and 3, the inverted L-type antennas 200 are arranged such that the point where each electric field is maximum on the glass plate 100 (the open end 226 of the radiator 220) is spaced apart from each other. By disposing, it is possible to minimize the influence of the electromagnetic coupling between each other. In particular, as shown in Figs. 2 and 3, any two adjacent inverted L-shaped antennas 200 having the same radiation characteristics may be arranged so that their respective deployment directions are orthogonal to each other, thereby providing electromagnetic coupling between the antennas. The influence by this can be further reduced.

The inverted L-shaped antennas 200 may be disposed along the edge of the glass plate 100, as shown in FIGS. 2 and 3. In this case, while other elements for the RF circuit, etc. are placed on the glass plate 100 is minimized, the effect of other elements on the electromagnetic wave transmission and reception performance of the inverted L-type antenna 200 is also minimized.

Since the inverted L-type antenna 200 which is not directly connected to the ground plane is used as the MIMO antenna according to the present embodiment, the current induced in the ground plane during the wireless communication is weak. In particular, by using the inverted L-shaped antenna 200 of 3/8 times, 5/8 or 3/4 times the wavelength with respect to the resonant frequency, the current induced in the ground plane is electromagnetically different from other antennas. Coupling can minimize the effect on other antennas. In addition, in order to minimize interference due to electromagnetic coupling between the inverted L-type antennas 200, the insulators between the antennas may be disposed by arranging the inverted L-shaped antennas 200 so that the open ends 226 of the radiator 220 are spaced apart from each other. Is significantly improved.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. . Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

1 is a perspective view of an inverted L-type antenna included in a MIMO system installed in a vehicle according to an embodiment of the present invention.

2 and 3 are a plan view and a perspective view briefly showing an installation state of the MIMO system according to the present embodiment, respectively.

4 and 5 illustrate in-vehicle formation positions of a MIMO system in accordance with one embodiment of the present invention.

Claims (8)

In a MIMO system installed in a vehicle, Two or more antennas disposed on the glass plate; An antenna signal terminal of the RF circuit electrically connected to the feed terminal of the antenna, The antennas are arranged such that the point at which each electric field is maximum is spaced apart from each other at maximum. The method of claim 1, The number of antennas is 4, The first antenna and the second antenna are disposed to be spaced apart a predetermined distance from the upper edge of the glass plate, And a third antenna and a fourth antenna are spaced apart from the bottom edge of the glass plate by a predetermined distance. The method according to claim 1 or 2, And the antenna has an electrical length of any one of 3/8 times length, 5/8 times length and 3/4 times length of the wavelength for its resonant frequency. The method according to claim 1 or 2, Any two antennas of the antennas are arranged such that their respective placement directions are orthogonal to each other. The method according to claim 1 or 2, The antennas are disposed along an edge of the glass plate. The method of claim 1, The antenna is mounted in the case of the conductor, The case operating with a ground plane. The method of claim 6, And the case is detachable from the glass plate. The method of claim 1, The MIMO system is formed in the rear window, the front window, the rearview mirror or the rearview mirror of the vehicle.

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