KR20160104585A - Internal antenna - Google Patents

Abstract

Disclosed is an embedded antenna which is installed in a vehicle or a structure having an exterior with a structure which is difficult to radiate, increases radiation efficiency to the outside, and has an omnidirectional radiation pattern. According to an aspect of the present invention, the embedded antenna comprises: a plurality of antenna modules having different radiation directions; a ground area having a ground potential with respect to the antenna modules; a power supply line to supply a signal to the antenna modules; a power distributor to distribute the signal supplied from the power supply line to the antenna modules; and a /4 conversion unit positioned between the power distributor and the antenna modules to perform impedance matching. The antenna modules are symmetrically arranged around the /4 conversion unit.

Description

INTERNAL ANTENNA}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a built-in antenna, and more particularly to a built-in antenna embedded in a structure having a vehicle or a structure difficult to radiate.

As communications equipment develops, there is a tendency to provide a plurality of antennas for transmitting and receiving various kinds of radio signals to the inside and the outside of the vehicle. Here, various types of radio signals include Global Positioning System (GPS) signals, FM and AM radio signals for utilizing a location-based system equipped with vehicles, DMB (Digital Multimedia Broadcast) signals for viewing digital broadcasts in vehicles, A Telematics Management Unit (TMU) signal for Telematics communication, an XM satellite radio signal and a Sirius signal, a DAB (Digital Audio Broadcating) signal, and the like.

In the case of a built-in antenna mounted on a dashboard in a vehicle, the built-in antenna is generally implemented as a monopole antenna or an inverted F antenna. The antennas are omni-directional, Respectively. In this case, due to the influence of the metal body included in the vehicle or the like, the amount of the radio signals radiated by the built-in antenna can be restricted to a certain extent outside the vehicle as shown in Fig. Particularly, the higher the frequency of the transmission signal, the greater the influence of the metal body, so that the amount of the radio signal exiting the vehicle body is further reduced. That is, in the case of V2X (Vehicle to Everything) communication using a radio signal with a high frequency, the reception sensitivity in the built-in antenna is very bad and wireless communication is not smoothly performed. Such a problem is not limited to a silent vehicle, but also occurs when an antenna is embedded in a structure having a structure which is difficult to radiate.

An object of the present invention is to provide a built-in antenna having an omnidirectional radiation pattern, which is installed in a structure having a vehicle or a structure difficult to be radiated as an outer appearance, while enhancing radiation efficiency to the outside.

It is another object of the present invention to provide a built-in antenna which is provided in a structure having a vehicle or a structure difficult to be radiated as an outer appearance and simultaneously provides a high frequency band such as the V2X band and an LTE band.

According to an aspect of the present invention, there is provided an embedded antenna comprising: a plurality of antenna modules having different radial directions; A grounding region having a ground potential for the plurality of antenna modules; A feed line for supplying a signal to the plurality of antenna modules; A power distributor for distributing a signal supplied from the feeder line to the plurality of antenna modules; And a lambda / 4 conversion unit positioned between the power divider and the plurality of antenna modules to perform impedance matching, wherein the plurality of antenna modules are arranged in a symmetrical manner with respect to the lambda / 4 conversion unit, antenna.

Each of the plurality of antenna modules may be installed to be inclined with respect to a reference plane.

The angle between the plane of each of the plurality of antenna modules and the reference plane may be an acute angle.

The plurality of antenna modules including: a radiation patch; A reflection plate spaced apart from the radiation patch by a predetermined distance and disposed at a lower end of the radiation patch; And an RF cable passing through the reflection plate and connecting the? / 4 conversion unit and the radiation patch.

One side of the reflection plate is connected to the grounding region so that the reflection plate can perform reflection and grounding functions.

Wherein the RF cable includes: an inner core wire connecting the radiation patch and the? / 4 converter; And an outer core wire connecting the radiation patch, the reflection plate, and the grounding region.

The outer core portion of the RF cable between the reflector and the? / 4 converter can be removed.

The? / 4 conversion unit may be formed in multiple stages.

The built-in antenna may be installed inside the vehicle.

One of the plurality of antenna modules may be installed toward the front of the vehicle and the other may be installed toward the rear of the vehicle.

Further comprising an additional antenna module disposed on the opposite side of the plurality of antenna modules with the grounded region interposed therebetween, wherein the additional antenna module is an inverted F antenna and the plurality of antenna modules Can operate in different operating frequency bands.

The built-in antenna according to an embodiment of the present invention can be installed in a structure having a vehicle or a structure difficult to be radiated as an outer appearance to smoothly perform wireless communication and have a high radiation gain. Particularly, it is possible to smoothly provide 5th generation mobile communication service in a high frequency band to be served in future as well as V2X communication.

The built-in antenna according to an embodiment of the present invention is installed in a structure having a vehicle or a structure difficult to be radiated as an outer appearance, and utilizes a low-cost metal reflector as a ground, thereby achieving miniaturization of the antenna while increasing radiation gain radiated by the antenna. .

The built-in antenna according to an exemplary embodiment of the present invention simultaneously supports a high frequency band such as the V2X band and an LTE band to provide a multi-band characteristic.

1 is a view showing a radiation pattern of a built-in antenna of a conventional vehicle.
2 is a view showing a general form of a microstrip patch antenna.
3 is a view illustrating a microstrip patch antenna according to an embodiment of the present invention.
4 is a view showing a radiation pattern of the microstrip patch antenna of FIG.
5 is a view illustrating an internal antenna according to an embodiment of the present invention.
6 is a schematic view illustrating an incident angle of a radio signal to a vehicle having an internal antenna according to an embodiment of the present invention.
7 is a schematic view showing a signal radiation pattern of a vehicle having an internal antenna according to an embodiment of the present invention.
8 is a view illustrating a built-in antenna according to another embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, in order that those skilled in the art can easily carry out the present invention. In the following detailed description of the preferred embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. In the drawings, like reference numerals are used throughout the drawings.

A microstrip patch antenna is used as the built-in antenna according to an embodiment of the present invention. Microscript patch antennas are widely used because they are structurally simple, highly efficient, and conformal. One of the most common forms of microstrip patch antennas is a square patch. 2 is a view showing a general form of a microstrip patch antenna.

2, a typical type of microstrip patch antenna includes a ground 210, a dielectric 220, a feed line 230, and a radiation patch 240. Specifically, a typical rectangular radiation patch 240 having a width W and a length L over a dielectric 220 having a dielectric constant r with a ground 210 is shown. The size, that is, the width W and the length L of this general type microstrip patch antenna are obtained by the following equation (1).

(1)

Here,? _R is the permittivity of the dielectric,? _Eff is the effective permittivity, f is the operating frequency, and c is the speed of light.

FIG. 3 is a plan view of a microstrip patch antenna according to an embodiment of the present invention. FIG. 3 (a) is a plan view and FIG. 3 (b) is a side view. 4 is a view showing a radiation pattern of the microstrip patch antenna of FIG.

3, the microstrip patch antenna according to an exemplary embodiment of the present invention includes a ground 310, a feeder line 320, and a radiation patch 330. The microstrip patch antenna shown in FIG. 3 uses air in place of the dielectric, and the height h between the ground 310 and the radiation patch 330 is 5 mm. When the dielectric constant for air is 1, V2X (5.8 The width W of the radiation patch 330 for the GHz band is preferably 19.3 mm and the length L is preferably 25.8 mm. And the feeding point of the radiation patch 330 is separated by 4 mm from each of the near two edges. Such a microstrip patch antenna exhibits directivity in the radiation pattern as shown in FIG. 3 and 4, the case where the microstrip patch antenna supports the V2X band is described as an example. However, the signals to be transmitted and received include various signals such as AM, FM radio signals, 3G signals, LTE (Long Term Evolution) And may include frequencies of 5G mobile communication services to be applied in the future. By using a plurality of such microstrip patch antennas to manufacture a built-in antenna of a vehicle, it is possible to realize an omnidirectional radiation pattern based on a vehicle radiation standard. The embodiment will be described in detail with reference to FIG.

5 is a view illustrating an internal antenna according to an embodiment of the present invention. 5, the internal antenna according to the present embodiment includes a main board 510, a feeder line 520, a power divider 530, a? / 4 converter 540, Modules 550 and 560, respectively.

The main board 510 includes a ground area 511 as shown in FIG. 5 as a printed circuit board (PCB) or the like. 5, both side portions 511a of the grounding region 511 extend in the longitudinal direction along the side surface of the main board 510 so that the grounding region 511 finally has a ' . The grounding region 511 has a ground potential at a predetermined distance from the radiation patches 553 and 563 of the plurality of antenna modules 550 and 560.

The feeder line 520 receives, for example, the V2X signal from the AVN (Audio Video Navigation) system of the vehicle, and transmits it to the power distributor 530. The feed line 520 may be in the form of a cable. Preferably, the feeder line 520 is connected to the feed point of the main board 510 and is connected to the power divider 530.

The power divider 530 distributes the signal to the plurality of antenna modules 550 and 560 at a predetermined ratio while performing a function as a feeder line for supplying a signal received from the feeder line 520 to the? . The power distributor 530 is implemented in the form of a strip line in the main board 510.

As shown in FIG. 5, a λ / 4 converter 540 is disposed between the power divider 530 and the plurality of antenna modules 550 and 560. The? / 4 conversion unit 540 performs impedance matching on the first antenna module 550 and the second antenna module 560 to apply the same feed to the first antenna module 550 and the second antenna module 560, And transmit and receive signals having the same phase to the first antenna module 550 and the second antenna module 560.

를 이용하여 제 1 변환부(541)의 특성 임피던스를 계산할 수 있으며, 상기 계산된 특성 임피던스에 따라 상기 도선의 너비를 결정할 수 있다. 여기서, Z_t1는 제 1 변환부(541)의 특성 임피던스, Z₁₁은 제 1 안테나 모듈(550)의 특성 임피던스, Z₁₂는 전력 분배기(530)의 스트립 라인의 특성 임피던스에 해당한다. The? / 4 conversion unit 540 may include a first conversion unit 541 and a second conversion unit 542. The first transducer 541 may be a conductor connected between the strip line of the first antenna module 550 and the power divider 530 and the length of the conductor may be the same as the center frequency of the first antenna module 550 (For example, 1.25 cm in the case of the V2X band), and the width of the conductor is equal to the characteristic impedance of the first antenna module 550 and the characteristic impedance of the strip line of the power divider 530 Can be set according to the characteristic impedance. here,

The characteristic impedance of the first conversion unit 541 can be calculated using the calculated characteristic impedance, and the width of the conductor can be determined according to the calculated characteristic impedance. Here, Z _t1 corresponds to the characteristic impedance of the first converter 541, Z ₁₁ corresponds to the characteristic impedance of the first antenna module 550, and Z ₁₂ corresponds to the characteristic impedance of the strip line of the power divider 530.

를 이용하여 제 2 변환부(542)의 특성 임피던스를 계산할 수 있으며, 상기 계산된 특성 임피던스에 따라 상기 도선의 너비를 결정할 수 있다. 여기서, Z_t2는 제 2 변환부(542)의 특성 임피던스, Z₂₁은 제 2 안테나 모듈(560)의 특성 임피던스, Z₂₂는 전력 분배기(542)의 스트립 라인의 특성임피던스에 해당한다. Similarly, the second conversion unit 542 may be a line connected to the strip line of the second antenna module 560 and the power divider 530, and the length of the line may be the center frequency of the second antenna module 560 And the width of the conductor may be set to the characteristic impedance of the second antenna module 560 and the characteristic impedance of the strip line of the power divider 530. [ In the same way

The characteristic impedance of the second conversion unit 542 can be calculated using the characteristic impedance and the width of the conductive line can be determined according to the calculated characteristic impedance. Here, Z _t2 corresponds to the characteristic impedance of the second conversion section 542, Z ₂₁ corresponds to the characteristic impedance of the second antenna module 560, and Z ₂₂ corresponds to the characteristic impedance of the strip line of the power distributor 542.

Here, as shown in FIG. 5, the? / 4 conversion unit 540 can also implement the first conversion unit 541 and the second conversion unit 542 in multiple stages. That is, the first transforming unit 541 and the second transforming unit 542 may be implemented by a multisection transformer, wherein each of the stages may have a length of? / 4, May be set according to the characteristic impedance of the module (550, 560) and the characteristic impedance of the strip line of the power divider (530). A three-stage transfomer can be used if the impedance of the antenna is 100 ohms and the impedance of the communication system is 50 ohms.

Each of the plurality of antenna modules 550 and 560 includes antenna feed lines 551 and 561, reflectors 552 and 562 and radiation patches 553 and 563 as shown in Fig.

The antenna feed lines 551 and 561 include an inner conductor and an outer conductor as RF cables and an inner core wire connects the patches 553 and 563 and the? / 4 converter 540, The outer core wire connects the radiation patches 553 and 563 to the reflection plates 552 and 562 and the grounding region 511. For this, the outer core between the reflection plates 552 and 562 and the? / 4 conversion unit 540 is preferably removed so that only the inner core is exposed.

The radiation patches 553 and 563 radiate a signal to the outside as a rectangular radiator or receive a signal from the outside. The radiation patches 553 and 563 can be designed in the same manner as the general rectangular microstrip patch antenna design method. In this embodiment, the quadrangles are described as the shapes of the radiation patches 553 and 563, but the present invention is not limited thereto and may have various shapes.

The reflection plates 552 and 562 reflect signals transmitted and received by the radiation patches 553 and 563, thereby enhancing the directivity of the radiation patterns of the antenna modules 550 and 560. As shown in Fig. 5, the reflection plates 552 and 562 are spaced apart from the radiation patches 553 and 563 by a predetermined distance (for example, 5 cm in the case of the V2X band). The areas of the reflection plates 552 and 562 are preferably larger than the areas of the radiation patches 553 and 563 and are preferably rectangular and parallel to the radiation patches 553 and 563. The directional direction of the antenna modules 550 and 560 may be determined by the physical arrangement and shape of the radiation patches 553 and 563 and the reflection plates 552 and 562. The reflection plates 552 and 562 perform a grounding function in addition to the reflection function. Specifically, one side of the reflector 552, 562 is connected to a grounded area 511a extending along the side of the mainboard 510. [

The plurality of antenna modules 550 and 560 are arranged so that the radial directions of the signals are different from each other. That is, if the radiation direction of the first antenna module 550 is the first direction, the radiation direction of the second antenna module 560 is arranged to be the second direction instead of the first direction. For example, as shown in FIG. 5, if the radiation direction of the first antenna module 550 of the plurality of antenna modules 550 and 560 is forward, the radiation direction of the second antenna module 560 is the reverse of the reverse direction.

In addition, the plurality of antenna modules 550 and 560 are arranged to be inclined with respect to the reference plane. Here, the reference surface may be a ground surface, or may be the main board 510 of the present invention. 5, the plurality of antenna modules 550 and 560 according to the present embodiment are parallel to the main board 510 or are not perpendicular to the main board 510 and are inclined relative to the main board 510 . The patches 553 and 563 of the antenna modules 550 and 560 and the reflection plates 552 and 562 are inclined at a certain angle with respect to the reference plane (e.g., the main board 510 or the ground). 5, the antenna module 550 and the antenna module 560 are disposed symmetrically with respect to the longitudinal direction of the? / 4 conversion unit 540, and are arranged so as not to face each other. The angle formed by the plane of the first antenna module 550 and the plane of the second antenna module 560 may be selected according to the angle of a radio wave incident into the structure of a vehicle or the like. It is preferable that the angle between the plane of the first antenna module 550 and the plane of the second antenna module 560 is an acute angle.

5, the two antenna modules 550 and 560 are not opposed to each other and are spaced apart from each other in the longitudinal direction of the main board 510. However, the two antenna modules 550 and 560 may be connected to the? / 4 converter 540, As shown in Fig.

As described above, a typical microstrip patch antenna has directivity. Therefore, if a microstrip patch antenna is used as an internal antenna of a vehicle, the signal attenuation due to the influence of the vehicle body can be compensated. However, in general, the internal antenna of the vehicle should have an omnidirectional direction. It does not satisfy such an omnidirectional characteristic. However, according to the embodiment of the present invention described above, a plurality of antenna modules 550 and 560 using directional microstrip patch antennas are arranged symmetrically with respect to the main board 510 (or the ground) And can be used in a structure having a vehicle or a structure difficult to be radiated as an outer appearance.

6 is a schematic view illustrating an incident angle of a radio signal to a vehicle having an internal antenna according to an embodiment of the present invention. As shown in Fig. 6, the signals incident on the vehicle c can be strongly incident in an angular range of 0 to 20 degrees. Therefore, when the built-in antenna according to the embodiment of the present invention is installed in the vehicle, the arrangement angles of the plurality of antenna modules 550 and 560 in consideration of the angle range of 0 to 20 degrees, Can be set. Here, the arrangement angle is an angle formed by the plane of each of the antenna modules 550 and 560, and is preferably 30 to 70 degrees.

7 is a schematic view showing a signal radiation pattern of a vehicle having an internal antenna according to an embodiment of the present invention. The embodiment of FIG. 7 is arranged such that each of the plurality of antenna modules 550 and 560 of the built-in antenna according to the embodiment of the present invention faces the front and rear of the vehicle, respectively. Conventionally, as shown in FIG. 1, a transmission signal emitted by the built-in antenna of a vehicle due to the influence of a metal body or the like is hardly transmitted outside the vehicle body. However, in the case of using the built-in antenna according to the embodiment of the present invention, as shown in FIG. 7, the sum of the radiation patterns of the two antenna modules 550, Since a relatively large transmission signal can be transmitted to the outside of the vehicle c due to the directional radiation, a transmission signal of a high frequency such as a V2X signal can be transmitted and received through the built-in antenna of the vehicle. The built-in antenna according to the embodiment of the present invention can exhibit high radiation gain and omnidirectionality with only a low-cost metal structure, not using an expensive ceramic patch.

8 is a view illustrating a built-in antenna according to another embodiment of the present invention. The built-in antenna according to the present embodiment with reference to FIG. 8 may further include an additional antenna module 800 on the opposite side of the plurality of antenna modules 550 and 560 with respect to the ground area 511 in the built- . The additional antenna module 800 is an inverted F-type antenna as an antenna module for LTE.

The additional antenna module 800 includes two radiators 830a and 830b. The two radiators 830a and 830b are connected to the ground pads 850a and 850b and the feed pads 820a and 820b for the transmission and reception of radio signals and are supported by the dielectric 840. The dielectric 840 is a hexahedral structure and the two radiators 830a and 830b of the additional antenna module 800 extend from the bottom of the dielectric 840 along each side of the hexahedron 840. The number, width, and length of bending of the two radiators 830a and 830b can be adjusted according to the operating frequency band, the installation environment, and the like.

It further includes two feeder lines 810a and 810b for feeding signals to the additional antenna module 800, as shown in FIG. The additional antenna module 800 further includes two feeder lines 810a and 810b connected to the two radiators 830a and 830b since the antenna module 800 includes two radiators 830a and 830b as described above. The two feeder lines 810a and 810b are connected to the feed pads 820a and 820b provided on the bottom surface of the dielectric 840.

The built-in antenna described with reference to FIG. 8 has a multi-band characteristic by including a plurality of antenna modules 550 and 560 in the V2X band and an additional antenna module 800 in the LTE band.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be understood that various modifications and changes may be made without departing from the scope of the appended claims.

510: Motherboard
511: Grounding area
550, 560: Antenna module
553, 563: radiation patch
552, 562: reflector
520: Feeder
530: Power distributor
540:? / 4 conversion section

Claims (11)

A plurality of antenna modules having different radial directions;
A grounding region having a ground potential for the plurality of antenna modules;
A feed line for supplying a signal to the plurality of antenna modules;
A power distributor for distributing a signal supplied from the feeder line to the plurality of antenna modules; And
And a lambda / 4 converter located between the power divider and the plurality of antenna modules to perform impedance matching,
Wherein the plurality of antenna modules are symmetrically arranged with respect to the? / 4 conversion unit. The method according to claim 1,
Wherein each of the plurality of antenna modules is inclined with respect to a reference plane. 3. The method of claim 2,
Wherein an angle between the plane of each of the plurality of antenna modules facing the reference plane is an acute angle. The method according to claim 1,
Wherein the plurality of antenna modules comprise:
Radiation patch;
A reflection plate spaced apart from the radiation patch by a predetermined distance and disposed at a lower end of the radiation patch; And
And an RF cable passing through the reflection plate and connecting the? / 4 conversion unit and the radiation patch. 5. The method of claim 4,
Wherein one side of the reflection plate is connected to the ground region so that the reflection plate performs reflection and grounding functions. 6. The method of claim 5,
The RF cable includes:
An inner core connecting the radiation patch and the? / 4 converter; And
And an outer core wire connecting the radiation patch, the reflection plate, and the grounding region. The method according to claim 6,
And the outer core portion of the RF cable between the reflection plate and the? / 4 conversion portion is removed. The method according to claim 1,
Wherein the? / 4 conversion unit is formed in multiple stages. The method according to claim 1,
Wherein the built-in antenna is installed inside the vehicle. 10. The method of claim 9,
Wherein one of the plurality of antenna modules is installed toward the front of the vehicle and the other one is installed toward the rear of the vehicle. The method according to claim 1,
Further comprising an additional antenna module disposed on the opposite side to the plurality of antenna modules with the grounded region in between,
Wherein the additional antenna module is an inverted F antenna and operates in an operating frequency band different from that of the plurality of antenna modules.

Images