KR102198378B1 - Switched beam-forming antenna device and manufacturing method thereof - Google Patents

Abstract

Disclosed are a switch beamforming antenna device and a manufacturing method thereof. The switch beamforming antenna device includes a plurality of substrates having different dielectric constants. An antenna layer is formed on one surface of a substrate having a low dielectric constant among the plurality of substrates, and a Butler matrix layer is formed on one surface of a substrate having a high dielectric constant.

Description

Switched beam-forming antenna device and manufacturing method thereof TECHNICAL FIELD

The present invention relates to a switch beamforming antenna device capable of miniaturizing the size and a method of manufacturing the same.

The present invention is a patent filed as a part of research and development of information and communication broadcasting and technology development of the broadcasting and communication industry, and related matters are as follows.

Related 1

Research Project Name: Information and Communication Broadcasting R&D Project

Ministry name: Ministry of Science and Technology Information and Communication

Research and management professional institution: Information Communication Planning and Evaluation Institute

Research Project Title: University ICT Basic Lab (RF Beamforming Antenna and Transceiver Multifunctional MMIC Advanced Technology)

Research Institution (Organization): Kwangwoon University Industry-Academic Cooperation

Assignment identification number: 2017-0-00959

Research Period: 2019.01.01 ~ 2019.12.31

Related matter 2

Research Project Name: Broadcasting and Communication Industry Technology Development Project

Ministry name: Ministry of Science and Technology Information and Communication

Research and management professional institution: Information Communication Planning and Evaluation Institute

Research Project Name: Development of satellite receiving electronic phased array antenna technology for mobile objects

Research institute (main organization): Ace Technology Co., Ltd.

Assignment identification number: 2018-0-00712

Research Period: 2019.01.01 ~ 2019.12.31

The switched beamforming antenna system used in the millimeter wave band is a method of generating a specific beam pattern by switching to one beam pattern among a plurality of preset beam patterns. Such a switch beamforming method has a simple structure and high reproducibility of the generated beam pattern, and is widely used for 5G mobile communication terminals or base stations, short-range wireless communication in 60GHz band, and collision avoidance radar for 77GHz cars.

The core circuit that implements the switched beamforming antenna device is the Butler matrix. The Butler Matrix is a passive circuit network consisting of a hybrid coupler and a fixed phase shifter. According to which terminal is selected from among a plurality of signal input terminals, a phase interval of signals output from a plurality of output terminals is set to a predetermined desired value. A typical Butler matrix usually has a horizontal and vertical size corresponding to two to three times the wavelength of an operating frequency.

In more detail, FIG. 1 is a diagram showing the structure of a switched beamforming antenna including a general Butler matrix and an array antenna.

Referring to FIG. 1, the Butler matrix is a 4Х4 Butler matrix and includes three components: a hybrid coupler, a crossover coupler, and a fixed phase shifter.

In the case of the hybrid coupler shown in the small figure (A) included in Fig. 1, when the input signal is applied to P1, a signal with a 3dB attenuation and 90 degree phase delay is output at P2, and a 3dB attenuation and 0 degree delay at P3. Is output, and no output signal is generated in P4. In the case of the crossover coupler shown in the small figure (B) included in FIG. 1, input signals applied to P1 and P4 are transmitted to P3 and P2, respectively, and there is no signal transmission to other ports. In the case of the phase shifter shown in the small figure (C) included in FIG. 1, the output signal in which the phase value set for the signal input to P1 is displaced is output to P2. In the case of FIG. 1, the phase value of the phase shifter is 45 degrees.

FIG. 2 is a diagram illustrating a substrate structure of the switched beamforming antenna system of FIG. 1.

2 is a cross-sectional view of a substrate on which a conventional switch beamforming antenna system is implemented. The left figure of FIG. 2 shows a case where the entire antenna system is designed with a single dielectric layer, and the right figure of FIG. 2 is a case where the entire antenna system is designed by stacking multiple layers of dielectric layers from 1 to N layers. Is shown.

In the case of the first case, the conventional technology implemented as a single layer substrate, a single layer substrate is used, but a method of miniaturization by increasing the characteristic impedance of the applied micro stripline has been proposed. However, such a method of implementing a single-layer substrate has a disadvantage of deteriorating the entire beam pattern due to severe interference between signals occurring in the two structures due to structural limitations in that the antenna and the Butler matrix are implemented on the same plane.

In the case of the second case, the conventional technology implemented in a stacked structure on a multilayer substrate, it is possible to divide the array antenna and the Butler matrix into three or more sections, and implement each section on a multilayer substrate. However, there is a disadvantage in that performance degradation is severe due to interface mismatch between each section. On the other hand, using a multi-layered structure, it is miniaturized by applying a special structure such as a dual-line transmission line in a multilayered structure, a suspended stripline structure, or a substrate integrated waveguide (SIW) structure. There is a way to do it. However, in this case, the structure is complex and the implementation is difficult, so productivity is degraded. Moreover, in the past, all of the multilayer substrates used have used a homogeneous multilayer substrate made of the same dielectric material having the same dielectric constant.

The present invention is to provide a switch beamforming antenna device capable of minimizing its size and a method of manufacturing the same.

The present invention is to provide a switch beamforming antenna device and a method of manufacturing the same, which is easy to implement by implementing each layer of a substrate with a material having different electrical characteristics, has excellent performance, and is capable of miniaturizing the overall size.

Other objects of the present invention may be derived by those skilled in the art through the following examples.

According to one aspect of the present invention, a switch beamforming antenna device capable of minimizing the size is provided.

According to an embodiment of the present invention, a plurality of substrates having different dielectric constants are included, wherein an antenna layer is formed on one surface of a substrate having a low dielectric constant among the plurality of substrates, and a Butler matrix layer is formed on one surface of the substrate having a high dielectric constant. A switch beamforming antenna device, characterized in that it may be provided.

Each of the inner conductor surfaces formed by the stacking of the plurality of substrates is used as a ground.

The Butler matrix layer and the antenna layer may have a plurality of via holes, and a probe feeding structure in which a signal is transmitted from an output terminal of the Butler matrix to an antenna through the via holes.

A plurality of small slots are formed on the inner conductor surface used as a ground between the Butler matrix layer and the antenna layer, but have a slot-coupled feeding structure in which signals are transmitted from the output terminal of the Butler matrix to the antenna through the slots. I can.

The plurality of substrates may be bonded and laminated using a resin having a dielectric constant different from that of the plurality of substrates.

An array antenna is formed in the antenna layer, and the array antenna is a microstrip patch antenna.

The antenna layer is an array antenna is formed, the array antenna is a dipole antenna,

The thickness of the plurality of substrates is 0.3 mm or less, and the height and width are 37 mm or less.

According to another embodiment of the present invention, a first dielectric layer having a first dielectric constant; A second dielectric layer having a second dielectric constant; A first metal layer; And a second metal layer, wherein the first dielectric layer and the second dielectric layer are stacked, wherein the first metal layer and the second metal layer are on top of the first dielectric layer and the second dielectric layer or It is formed outside the lower portion, wherein the first metal layer and the second metal layer are electrically connected through vias penetrating the first dielectric layer and the second dielectric layer to form an antenna and a Butler matrix. A switch beamforming antenna device as characterized may be provided.

According to another embodiment of the present invention, a method of manufacturing a switched beamforming antenna is provided.

According to an embodiment of the present invention, the method may include depositing a first substrate and a second substrate by applying a prepreg to one surface of a first substrate having a first permittivity and a second substrate having a second permittivity; Forming a Butler matrix layer on the other surface of the first substrate; Forming an antenna layer on the other surface of the second substrate; And forming a plurality of via holes from the Butler matrix layer to the antenna layer.

By providing a small Butler matrix device and a beamforming antenna device including the same according to an embodiment of the present invention, each layer of the substrate is implemented with a material having different electrical characteristics, so that it is easy to implement, excellent in performance, and There is an advantage that the size can be miniaturized.

1 is a diagram showing a plan view of a general Butler matrix-based switched beamforming antenna system.
FIG. 2 is a view showing two cases of a substrate structure used to implement the conventional switch beamforming antenna system of FIG. 1, that is, a single layer substrate and a multilayer substrate.
3 is a view showing a switch beamforming antenna device according to an embodiment of the present invention.
4 is a cross-sectional view of a switched beamforming antenna device according to an embodiment of the present invention.
5 is a diagram showing an actual implementation example of a switched beamforming antenna device according to an embodiment of the present invention.
6 is a graph showing a result of measuring a beam pattern of a switched beamforming antenna device according to an embodiment of the present invention.
7 is a flow chart showing a method of manufacturing a switched beamforming antenna according to an embodiment of the present invention.

The singular expression used in the present specification includes a plural expression unless the context clearly indicates otherwise. In the present specification, terms such as “consisting of” or “comprising” should not be construed as necessarily including all of the various elements or various steps described in the specification, and some of the elements or some steps It may not be included, or it should be interpreted that it may further include additional elements or steps. In addition, terms such as "... unit" and "module" described in the specification mean units that process at least one function or operation, which may be implemented as hardware or software, or as a combination of hardware and software. .

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a view showing a switch beamforming antenna device according to an embodiment of the present invention, Figure 4 is a view showing a cross-section of the switch beamforming antenna device according to an embodiment of the present invention, Figure 5 is a view A diagram showing an actual implementation example of a switched beamforming antenna device according to an embodiment of the present invention, and FIG. 6 is a graph showing a result of measuring a beam pattern of a switched beamforming antenna device according to an embodiment of the present invention. .

Referring to FIG. 3, the switched beamforming antenna device is divided into a Butler matrix section 310 and an antenna section 320. According to an embodiment of the present invention, the Butler matrix section 310 and the antenna section 320 may be implemented by stacking substrates having different dielectric constants.

The Butler matrix section 310 includes 4 hybrid couplers, 2 phase shifters and 2 crossover couplers, as shown in FIG. 3.

In the Butler matrix to which the present invention is applied, the present invention can be applied to an 8Х8 structure and other variously modified structures in addition to the 4Х4 structure.

Hereinafter, for convenience of description, the present invention will be described based on a switched beamforming antenna system based on a 4Х4 Butler matrix. However, the present invention is not limited thereto.

The antenna section 320 is implemented by being stacked on the Butler matrix section 310. Here, the antenna section 320 includes an array antenna. The array antenna represents a microstrip patch antenna structure. The patch antenna performs front radiation. If end-fire radiation is required, a dipole-type Yagi-Uda antenna may be used instead of the patch antenna.

4 is a diagram illustrating a cross section of a switched beamforming antenna device.

Referring to FIG. 4, the switch beamforming antenna device 300 may be implemented as a hybrid stack-up multilayer substrate in which a plurality of substrates having different dielectric constants are stacked.

Among the hybrid stack-up multilayer substrates, a substrate having a low dielectric constant may form an antenna layer, and a substrate having a high dielectric constant may form a Butler matrix layer.

This will be described in more detail.

For convenience, it is assumed that a hybrid stack-up multilayer substrate is formed by stacking a first substrate 410 having a first dielectric constant and a second substrate 420 having a second dielectric constant.

Here, when the first dielectric constant is higher than the second dielectric constant, the Butler matrix layer 430 is formed on the first substrate 410, and the antenna layer 440 is formed on the second substrate 420 having a low dielectric constant. I can.

The first substrate 410 and the second substrate 420 may be stacked by a prepreg. Here, the prepreg dielectric constant may have a dielectric constant between the first dielectric constant and the second dielectric constant.

By using a hybrid stack-up multilayer substrate formed by stacking substrates with different dielectric constants as described above, the antenna layer and the Butler matrix layer are implemented on opposite surfaces to separate the antenna section and the Butler matrix section, thereby generating unnecessary waves in the Butler matrix structure. There is an advantage in that the overall antenna radiation pattern can be improved by suppressing the influence of the signal interference by the antenna structure.

In addition, the array antenna is implemented on a substrate having a low dielectric constant to increase the radiation efficiency of the antenna, and at the same time, the Butler matrix is implemented on a substrate having a high dielectric constant, thereby reducing the size of the entire antenna system.

In an exemplary embodiment of the present invention, description will be made on the assumption that the dielectric constant of the first substrate 410 is higher than that of the second substrate 420.

A hybrid stack-up multilayer substrate is formed by stacking the second substrate 420 on the first substrate 410, but a Butler matrix layer is formed on the first substrate 410, and an antenna layer is formed on the second substrate 420. Can be.

In this way, since the second substrate 420 is stacked on the first substrate 410, the lower outer conductor surface of the first substrate 410 is used to form the Butler matrix layer, and the second substrate 420 An antenna layer may be formed on the upper outer conductor surface. In addition, an inner conductor surface formed by stacking the first substrate 410 and the second substrate 420 is used as a ground terminal.

For example, the second substrate 420 may be a substrate of Taconic's TLY-5A (dielectric constant = 2.17), and the first substrate 410 is Taconic's RF-60A (dielectric constant = 6.15). It may be a phosphorus substrate.

In an embodiment of the present invention, a 28Ghz band antenna device is assumed. Accordingly, a 4 x 4 Butler matrix layer of 28 GHz band is formed on the first substrate 410, and the size may be 13 x 19 mm ² . Compared to a Butler matrix implemented on a conventional Rogers RT5880 (dielectric constant = 2.2) substrate by forming a Butler matrix layer on a substrate having a high dielectric constant using a hybrid stack-up multilayer substrate having a different dielectric constant as in an embodiment of the present invention. You can increase the size to about 85%. Although the embodiment of the present invention has been presented for a 28GHz 5th generation millimeter wave mobile communication band, it may be applied to all other frequency bands used for various millimeter wave communication and sensors such as 24GHz, 60GHz, 77GHz, 90GHz, 140GHz.

Table 1 shows the phase and insertion loss of an output signal at each output port of the Butler matrix according to the results of 3-Dimensional Electromagnetic Field Simulation of the Butler matrix according to an embodiment of the present invention.

The largest phase error occurs when the signal path is from the first port to the fifth port, and from the third port to the eighth port, and was confirmed to be 16 degrees, and a root mean square phase error of 7.4 degrees was obtained.

In addition, the insertion loss ranged from 5.3 dB -10 dB, and the average insertion loss was confirmed to be 8.1 dB. According to these design results, it was confirmed that the range was suitable for implementing the beamforming antenna device.

[Table 1]

Also, the first substrate 410 and the second substrate 420 are stacked by a prepreg, but the dielectric constant of the prepreg may be 4. This is only an example, and it is obvious that the permittivity may be different.

However, when at least two substrates having different dielectric constants are used, an antenna layer may be formed on a substrate having a low dielectric constant, and a Butler matrix layer may be formed below a substrate having a high dielectric constant.

In addition, the Butler matrix layer and the antenna layer are electrically connected through via holes. That is, a signal can be transmitted by forming a through-hole via from the Butler matrix output terminal to the antenna. The Butler matrix layer and the antenna layer may be electrically connected through a probe feeding structure using a through-hole via.

In addition, a structure in which the Butler matrix layer and the antenna layer are combined in a slot structure is also possible. That is, a small slot hole is formed in the ground plane between the antennas at the Butler matrix output terminal, and through this, a slot-combining structure in which the Butler matrix output signal is connected to the antenna can be implemented.

Referring to Figure 4, the prepreg layer may be formed within 0.1 mm.

5 is a diagram showing an actual implementation example of a switched beamforming antenna device according to an embodiment of the present invention.

FIG. 5(a) is an illustration of the upper outer conductor surface of the substrate on which the antenna layer is formed among the hybrid stack-up multilayer substrate, and FIG. 5(b) is the lower outer conductor of the substrate on which the antenna layer is formed among the hybrid stack-up multilayer substrate. It is an example of the side.

The height and width shown in FIG. 5 are shown in Table 2.

[Table 2]

5 is only an example, and it is natural that the actual size for implementing the antenna may be different depending on the number of antenna arrays, the operating frequency, and the dielectric constant of the substrate. 6 is a graph showing a result of measuring a beam pattern of a switched beamforming antenna device according to an embodiment of the present invention.

When signals are respectively applied to the first input port, second input port, third input port, and fourth input port, the beam steered one step to the left from the output (1L), the beam steered in two steps to the left (2L), It can be seen that the beam 1R steered to the right step 1 and the beam 2R steered step 2 to the right respectively.

The steering angle of the 1L beam is -16 ^o and the side lobe level is -12 dB. The steering angle of the 2L beam is -39 ^o and the side lobe level is -6 dB. The steering angle of the 1R beam is +7 ^o and the lateral lobe level is -13.8 dB. Finally, the steering angle of the 2R beam is +36 ^o and the side lobe level is -11.7 dB.

It can be seen from FIG. 6 that four radiation patterns are generated at a desired steering angle.

In order to compare the degree of miniaturization of the antenna system actually manufactured and implemented in the present invention, the size of the antenna system implemented in the prior art was normalized and compared. The normalized dimension was calculated by dividing the actual size of the implemented antenna system by the square of the wavelength λ ² in the free space corresponding to the operating frequency and the number of switched beam directions. For example, the size of the antenna system according to an embodiment of the present invention is 4.12 mm ² , which corresponds to 3.57λ ² . The normalization size obtained by dividing this by λ ² and the number of beams is 0.9.

Meanwhile, as a result of searching for antenna systems of three different designs implemented in the prior art with reference to existing documents and calculating their normalized sizes, 1.3, 6.3, and 16.4 were obtained, respectively. That is, it can be seen that the antenna device implemented on the basis of the hybrid stack-up multilayer substrate having different dielectric constants, as in an embodiment of the present invention, has a smaller size than the conventional one.

As a result, it can be seen that the switched beamforming antenna device according to an embodiment of the present invention is very effective in miniaturization.

In summary, according to an embodiment of the present invention, the switch beamforming antenna device 100 is formed by stacking a plurality of dielectric layers having different dielectric constants, and metal layers may be formed on the upper and lower sides of the dielectric layer. Here, an antenna may be formed on an outer conductor surface having a low permittivity, and a Butler matrix may be formed on an outer conductor surface having a high permittivity. Accordingly, at the output terminal of the Butler matrix, antennas are electrically connected through via holes, respectively, so that a plurality of via holes may be formed to transmit signals. As described above, according to an embodiment of the present invention, there is an advantage in that it is possible to manufacture a switch beamforming antenna having a smaller size compared to the related art through a multilayer structure in which a plurality of dielectric layers (substrates) having different dielectric constants are stacked.

7 is a flowchart showing a method of manufacturing a switched beamforming antenna according to an embodiment of the present invention.

In step 710, one surface of the first substrate having the first dielectric constant and one surface of the second substrate having the second dielectric constant are disposed to face each other, and a prepreg is applied therebetween to stack the first substrate and the second substrate.

In step 715, a Butler matrix layer is formed on the other surface of the first substrate having the first dielectric constant.

At 720, an antenna layer is formed on the other surface of the second substrate having a second dielectric constant.

In step 725, a through-hole via is drilled from the Butler matrix output terminal to the antenna surface and electrically connected.

That is, after forming a hybrid stack-up multilayer substrate having different dielectric constants, an antenna layer is formed on the outer conductor surface of the substrate having a low dielectric constant, and a Butler matrix layer is formed on the outer conductor surface of the substrate having a high dielectric constant.

In this case, in the hybrid stack-up multilayer substrate, the inner conductor surface may be used as a ground terminal.

In addition, as already described above, in laminating the other surface of the second substrate on the other surface of the first substrate, a resin (prepreg) having a dielectric constant (third permittivity) between the first and second dielectric constants is used. The first substrate and the second substrate can be stacked.

So far, the present invention has been looked at around the embodiments. Those of ordinary skill in the art to which the present invention pertains will be able to understand that the present invention may be implemented in a modified form without departing from the essential characteristics of the present invention. Therefore, the disclosed embodiments should be considered from an illustrative point of view rather than a limiting point of view. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope equivalent thereto should be construed as being included in the present invention.

100: switch beamforming antenna device
110: Butler Matrix section
120: antenna section

Claims (10)

Including a plurality of substrates having different dielectric constants,
An antenna layer is formed on one surface of a substrate having a low dielectric constant among the plurality of substrates, and a Butler matrix layer is formed on one surface of a substrate having a high dielectric constant,
A plurality of small slots are formed on the inner conductor surface used as a ground between the Butler matrix layer and the antenna layer,
A switch beamforming antenna device comprising a slot coupled feeding structure in which signals are transmitted from the output terminal of the Butler matrix to the antenna through the slot.
The method of claim 1,
Each of the inner conductor surfaces formed by the stacking of the plurality of substrates is used as a ground.
delete delete The method of claim 1,
A switch beamforming antenna device, wherein the plurality of substrates are bonded and laminated using a resin having a dielectric constant different from that of the plurality of substrates.
The method of claim 1,
The antenna layer is formed with an array antenna,
The array antenna is a switch beamforming antenna device, characterized in that the microstrip patch antenna.
The method of claim 1,
The antenna layer is formed with an array antenna,
The array antenna is a switch beamforming antenna device, characterized in that the dipole antenna.
The method of claim 1,
The plurality of substrates have a thickness of 0.3 mm or less, and a height and width of 37 mm or less.
A first dielectric layer having a first dielectric constant;
A second dielectric layer having a second dielectric constant;
A first metal layer; And
Comprising a second metal layer,
The first dielectric layer and the second dielectric layer are stacked,
The first metal layer and the second metal layer are formed outside or above the first dielectric layer and the second dielectric layer,
The first metal layer and the second metal layer are electrically connected through vias penetrating the first dielectric layer and the second dielectric layer to form an antenna and a Butler matrix. Antenna device.
Laminating the first substrate and the second substrate by coating a prepreg on one surface of the first substrate having a first dielectric constant and one surface of the second substrate having a second dielectric constant;
Forming a Butler matrix layer on the other surface of the first substrate;
Forming an antenna layer on the other surface of the second substrate; And
And forming a plurality of via holes from the Butler matrix layer to the antenna layer.

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