KR102071819B1 - Wideband and high-gain patch abtenna using metamaterial structure - Google Patents

Abstract

According to one embodiment of the present invention, provided is a broadband high gain antenna using a meta-structure, which comprises: an opening coupled feed patch antenna in which a plurality of patch antennas are arranged at predetermined intervals along a longitudinal direction; and a plurality of meta-material resonators arranged on the opening coupled feed patch antennas, wherein unit cells including a plurality of split ring resonators and built-in capacitors are arranged in two dimensions.

Description

Wideband high gain antenna using meta structure {WIDEBAND AND HIGH-GAIN PATCH ABTENNA USING METAMATERIAL STRUCTURE}

The present invention relates to a wideband high gain antenna using a metastructure, and more particularly, to a wideband high gain antenna using a metastructure that can have a high performance by applying a metamaterial-based resonator to a patch antenna.

Microstrip patch antennas are easy to manufacture and inexpensive, and are used in various technical fields such as radar and communication.

However, conventional microstrip antennas have disadvantages of inherently narrow bandwidth and low directivity, and these disadvantages limit the utilization of a wide range of patch antennas. Therefore, the wireless system has a lot of interest in improving the performance of the antenna to solve this disadvantage.

As a technique for improving bandwidth, a technique using resonant aperture has been proposed. This is a method of isolating fake feed radiation by using a common ground plane, but can improve the bandwidth of the antenna, but has a problem similar to the conventional antenna has a problem that it is difficult to expect the antenna gain improvement effect.

In addition, there is a method of arranging the antennas as a method of improving the gain of the antenna, and this method also has a problem in that the planar size of the antenna increases as the number of arrays increases, and it becomes complicated in design.

Korea Patent Registration No. 10-1700403 Korea Patent Registration No. 10-1650340

One aspect of the present invention provides a wideband antenna using a metastructure that can improve antenna gain while maintaining bandwidth characteristics of a microstrip patch antenna.

The technical problem of the present invention is not limited to the technical problem mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

In the broadband high gain antenna using a meta structure according to an embodiment of the present invention, a plurality of patch coupling antennas are arranged at predetermined intervals along a length direction and a plurality of aperture coupling feed patch antennas are disposed on the aperture coupling feed patch antennas. The metamaterial resonator includes a two-dimensional unit cell including a plurality of split ring resonators and a built-in capacitor.

The aperture coupled feed patch antenna may include: a first substrate having the plurality of patch antennas formed at predetermined intervals along a length direction; And a second substrate disposed at a lower end of the first substrate and having an upper surface formed with an opening through which radio waves radiated from the patch antenna are passed, and a lower surface disposed under the upper surface and formed with a feed line.

The openings may be provided in the same number as the number of the patch antennas, and each of the openings may be matched one-to-one with the plurality of patch antennas.

The opening may have a rectangular shape having the same length direction as that of the opening coupling feed patch antenna.

The feed line may include: a first feed line connecting two adjacent patch antennas; And a second feed line connecting two neighboring first feed lines.

The split ring resonator is provided in a quadrangular ring shape having a gap formed at a center of an upper side or a lower side, and the unit cells have four overlapping split ring resonators, which gradually increase in size from the inside toward the outside with respect to a center point. It may be in the form.

The unit cell may include a first split ring resonator having a first width and a gap formed at a lower side thereof; A second split ring resonator having a second width greater than the first width and having a gap formed at an upper side thereof; A third split ring resonator having a third width greater than the second width and having a gap formed at a lower side thereof; And a fourth split ring resonator having a fourth width greater than the third width and having a gap formed at an upper side thereof.

The built-in capacitor may be inserted into the unit cell in a gap formed at the center of the upper side of the fourth split ring resonator formed at the outermost part.

The metamaterial resonator may be provided in plural, and each of the metamaterial resonators may be disposed in a vertical direction above the predetermined distance away from the aperture coupling feed patch antenna.

According to one aspect of the present invention, it is possible to implement a wideband antenna by using the Aperture coupled feed patch structure, and to apply not only the antenna arrangement but also the meta structure to the upper part of the antenna to have a great influence on the bandwidth characteristics of the existing antenna. The gain of the antenna can be improved without implementing an antenna having high performance.

1 is a perspective view showing a schematic configuration of a broadband high gain antenna using a meta structure according to an embodiment of the present invention.
FIG. 2 is an exploded perspective view illustrating a specific configuration of the aperture coupled feed patch antenna of FIG. 1.
3 is a diagram illustrating a specific configuration of the metamaterial resonator of FIG. 1.
4 is a diagram illustrating a specific configuration of a unit cell constituting the metamaterial resonator of FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION The following detailed description of the invention refers to the accompanying drawings that show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It is to be understood that the various embodiments of the invention are different but need not be mutually exclusive. For example, certain shapes, structures, and characteristics described herein may be embodied in other embodiments without departing from the spirit and scope of the invention in connection with one embodiment. In addition, it is to be understood that the location or arrangement of individual components within each disclosed embodiment may be changed without departing from the spirit and scope of the invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims, along with the full scope of equivalents to which such claims are entitled. Like reference numerals in the drawings refer to the same or similar functions throughout the several aspects.

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

1 is a diagram illustrating a schematic configuration of a wideband high gain antenna 1 using a metastructure according to an embodiment of the present invention.

Specifically, the broadband high gain antenna 1 using the meta structure according to the embodiment of the present invention may include an opening coupling feed patch antenna 100 and a metamaterial resonator 200.

Aperture-Coupled Feed Patch Antenna (ACFPA) is a device that emits or receives radio waves.

The aperture-coupled feed patch antenna 100 (hereinafter referred to as ACFPA) according to the present invention may be designed in such a manner that a plurality of patch antennas are arranged at predetermined intervals along the length direction as shown in order to improve the bandwidth of a conventional microstrip antenna. have. In this regard, it will be described with reference to FIG.

2 is an exploded perspective view showing a specific configuration of the ACFPA 100 of FIG.

Specifically, the ACFPA 100 according to the embodiment of the present invention may be an antenna structure composed of the first substrate 110 and the second substrate 120.

A plurality of patch antennas 111a, 111b, 111c, and 111d may be disposed on the first substrate 110 at predetermined intervals along the length direction. In the illustrated embodiment, four patch antennas 111a, 111b, 111c, and 111d are disposed at predetermined intervals along the length direction on the first substrate 110 of 122.6 mm * 3 342.8 mm * 5.7 mm. . In addition, the first substrate 110 may be designed as an FR4 (EpoxyResin) substrate having a dielectric constant of 4.4. However, the number of patch antennas and the dielectric constant of the first substrate 110 are not limited to the above-described example, but the number of patch antennas and the dielectric constant of the first substrate 110 to set the bandwidth and the center frequency size according to the purpose of use. Of course, the design may be changed.

The second substrate 120 may be formed under the first substrate 110 and may include an upper surface 121 and a lower surface 122.

Openings 121a, 121b, 121c, and 121d through which the radio waves radiated from the patch antennas pass may be formed in the upper surface 121 at predetermined intervals.

Each of the openings 121a, 121b, 121c, and 121d may be provided in a slit form for passing radio waves, and specifically, may be designed as a hole having a rectangular shape having the same length direction as that of the ACFPA 100. Can be.

In addition, each of the openings 121a, 121b, 121c, and 121d may correspond one-to-one with the patch antennas 111a, 111b, 111c, and 111d. At the same time, any one opening may be formed on the central portion of any one patch antenna. For example, when there are four patch antennas, four openings may also be formed, and the first opening 121a is formed below the center of the first patch antenna 111a to radiate radio waves emitted from the first patch antenna 111a. You can pass it.

The lower surface 122 may be stacked below the upper surface 121, and a feed line may be formed on the lower surface 122.

Here, the feed line may be composed of the first feed line (122a, 122b) and the second feed line (122c).

The first feed lines 122a and 122b may be designed to connect two neighboring patch antennas. For example, the first feed line 122a formed on the left side of FIG. 2 connects the first patch antenna 111a and the second patch antenna 111b, and the first feed line 122b formed on the right side is the third The patch antenna 111c and the fourth patch antenna 111d may be connected.

The second feed line 122c may be a feed line connecting two first feed lines 122a and 122b spaced apart from each other.

As such, ACFPA 100 according to an embodiment of the present invention is composed of two substrates (110, 120) separated by a ground plane, ACFPA according to an embodiment of the present invention having a structure as described above ( 100) has a center frequency at 3.2 GHz and 15% bandwidth (2.95-3.45 GHz). Thus, the ACFPA 100 structure has broadband characteristics. The gain in the frequency range can be expressed as 12.5 dBi at the center frequency.

The metamaterial resonator 200 may be disposed in plural on the opening coupling feed patch antenna, and may have a two-dimensional arrangement of unit cells including a plurality of split ring resonators and a built-in capacitor. In this regard, it will be described with reference to FIGS. 3 and 4 together.

3 and 4 are views for explaining a specific structure of the metamaterial resonator 200 of FIG.

As shown in FIG. 1, the metamaterial resonator 200 according to the present invention is provided in plural, and each metamaterial resonator 200 is spaced apart from the opening coupling feed patch antenna 100 by a predetermined distance (for example, as shown in FIG. 1). 60mm) may be disposed in the vertical direction.

In this case, as shown in FIG. 3, each metamaterial resonator 200 may be designed as a meta structure in which a plurality of unit cells 210 are two-dimensionally arranged.

The unit cell 210 may be provided in such a manner that four split ring resonators 211, 212, 213, and 214 having different sizes are overlapped with respect to a predetermined center point.

That is, each of the split ring resonators 211, 212, 213, and 214 is provided in a rectangular ring shape having a gap formed at the center of the upper side or the lower side, and the unit cell 210 gradually moves from the inside to the outside based on the center point. Four split ring resonators that are larger in size may have a pattern of overlapping arrangements.

In detail, the unit cell 210 has a first width and a first split ring resonator 211 having a gap formed at a lower side thereof, and a second split ring resonator having a second width greater than the first width and having a gap formed at an upper side thereof. 212, a third split ring resonator 213 having a third width greater than the second width and having a gap at the lower side thereof, and a fourth split ring resonator 214 having a fourth width greater than the third width and having a gap at the upper side thereof. The pattern consisting of) may be formed.

That is, the unit cell 210 is provided in a form in which four split ring resonators are gradually enlarged as the size increases toward the outer direction from the center, but the direction of the gap is formed so as to cross the upper direction and the lower direction. Split ring resonators may be arranged.

In this case, an internal capacitor 220 may be inserted into the gap formed at the center of the upper side of the fourth split ring resonator 214.

Meanwhile, the metamaterial resonator 200 according to the present invention may be designed to have a zero-refractive-index (ZRI) of transmittance close to zero in the 3 to 3.4 GHz band.

[Equation 1]

은 유전율,

은 투과율, n은 굴절율을 의미한다.here,

Silver permittivity,

Is the transmittance and n is the refractive index.

) 또는 투과율(

)의 값이 0에 가깝게되면, 메타물질 공진기(200)의 굴절(n) 또한 0에 가깝게 됨을 알 수 있다. 스넬의 법칙에 따르면, 제로 굴절률(ZRI) 구조에서 나가는 표면으로 전파되는 입사 파는 정상이며 제어파 지향성에 적용할 수 있다.According to the above equation, the dielectric constant (

) Or transmittance (

When the value of) is close to zero, it can be seen that the refraction n of the metamaterial resonator 200 is also close to zero. According to Snell's law, the incident wave propagating from the zero refractive index (ZRI) structure to the exiting surface is normal and can be applied to control wave directivity.

In addition, the transmittance may be calculated by the following equation.

[Equation 2]

Here, c is the luminous flux and d is the size of the unit cell 210.

The metamaterial resonator 200 according to the present invention was designed using a Taconic TLC 32 substrate having a dielectric constant of 3.2, and both sides of the substrate were used. The size of each unit cell 210 is 17.5mm * 17.5mm * 0.787mm, the unit cells 210 are arranged in 4 * 5, the meta-material resonator 200 is 90mm * 107.5mm * 0.787mm Can be.

Accordingly, the metamaterial resonator 200 according to the present invention may have a transmittance of almost zero in the frequency range of the 3-3.4 GHz band. Table 1 below shows the characteristics of the transmittance in the frequency range. As shown, the actual part of the transmittance at 3pF is -0.91 to -0.33 and can be seen to be close to zero compared to other capacitor values.

TABLE 1

The operating frequency may be controlled by changing the unit cell pattern and the gap size of the metamaterial resonator 200, but the metamaterial resonator 200 according to the present invention may include a built-in capacitor 220 of 3 pF to control the operating frequency. Can be arranged. Of course, if the produced metamaterials need to control the characteristics of the frequency, they can also be reconfigured to change the size, thickness and gap.

The metamaterial resonator 200 according to the present invention may operate as an inductor capacitor (LC) resonator. Therefore, the broadband high gain antenna 1 using the meta structure according to the present invention may be easier to control the frequency characteristics than the conventional antenna.

The wideband high gain antenna 1 using the metastructure according to the embodiment of the present invention having such a structure has a maximum gain of 12.98 dBi at 3.15 GHz. When six metamaterial resonators 200 are added, the gain can be measured through experiments to increase from 3.15 GHz to 15.7 dBi. That is, the metamaterial resonator 200 having the pattern according to the present invention may not only maintain bandwidth but also increase antenna gain.

Although described above with reference to the embodiments, those skilled in the art will understand that various modifications and changes can be made within the scope of the invention without departing from the spirit and scope of the invention as set forth in the claims below. Could be.

1: Broadband High Gain Antenna Using Meta Structure
100: aperture coupled feed patch antenna
200: metamaterial resonator

Claims (9)

An aperture coupled feed patch antenna in which a plurality of patch antennas are arranged at predetermined intervals along a length direction; And
Is disposed on the plurality of the opening coupling feed patch antenna, the unit cell consisting of a plurality of split ring resonator and a built-in capacitor includes a two-dimensional meta-material resonator,
The split ring resonator may be provided in a quadrangular ring shape having a gap formed at a center of an upper side or a lower side.
The unit cell has a form in which the four split ring resonators are gradually arranged in size from the inside to the outside with respect to a center point, and the first split ring resonator has a first width and a gap is formed at the lower side thereof. A second split ring resonator having a second width greater than a first width and having a gap formed at an upper side thereof, a third split ring resonator having a third width greater than the second width and having a gap formed at a lower side thereof, and a third larger than the third width; A fourth split ring resonator having a width of 4 and having a gap formed at an upper side thereof, and having the internal capacitor inserted in a gap formed at the center of the upper side of the fourth split ring resonator formed at the outermost part; antenna.
The method of claim 1, wherein the aperture coupling feed patch antenna,
A first substrate having the plurality of patch antennas formed at predetermined intervals along a length direction; And
A meta structure including a second substrate disposed at a lower end of the first substrate and including an upper surface formed with an opening through which radio waves radiated from the patch antenna pass, and a lower surface disposed under the upper surface and formed with a feed line. Broadband high gain antenna used.
The method of claim 2,
The opening is provided in the same number as the number of the patch antenna, each of the opening is a one-to-one matching with a plurality of the patch antenna, broadband high gain antenna using a meta structure.
The method of claim 2, wherein the opening,
And a rectangular shape having a length direction equal to a length direction of the aperture coupling feed patch antenna.
The method of claim 2, wherein the feed line,
A first feeding line connecting two neighboring patch antennas; And
And a second feed line connecting two neighboring first feed lines to each other.
delete delete delete The method of claim 1,
The metamaterial resonator is provided in plurality,
Wherein each of the metamaterial resonators is disposed in a vertical direction above the predetermined distance away from the aperture coupled feed patch antenna.

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