KR102695575B1 - Structural antenna including metal-coated fiber for antenna patch - Google Patents

Abstract

A structural antenna includes a base layer, a patch antenna pattern disposed on a first surface of the base layer and including a metal-coated fiber, a via feeder penetrating the base layer and electrically connected to the patch antenna pattern, and a ground layer disposed on a second surface of the base layer opposite to the first surface. The patch antenna pattern is strongly coupled to the base layer, so that the mechanical properties and reliability of the structural antenna can be increased.

Description

{STRUCTURAL ANTENNA INCLUDING METAL-COATED FIBER FOR ANTENNA PATCH}

The present invention relates to an antenna, and more particularly, to a structural antenna using a metal-coated fiber as an antenna patch.

Antennas are used for various purposes such as communication, detection, and friend/friend identification. A large number of antennas are applied to aircraft as they are used for various purposes, and the number and type vary depending on the type of aircraft, but dozens of antennas are installed on one aircraft. Therefore, antennas used in aircraft should be light in order to increase fuel efficiency, and thin in order to design an aerodynamically advantageous aircraft.

Patch antennas are widely used as aircraft antennas due to their light and thin characteristics. A patch antenna is a simple and thin antenna composed of a dielectric substrate, a conductive patch for radiation, and a conductive film for grounding. Because of its thin shape, it is easy to apply to the surface of an aircraft. However, it has electromagnetic limitations such as low gain and narrow frequency band, and recently, research is being conducted to increase the thickness of the antenna or to arrange multiple antennas on one plane (array antenna) to solve these electromagnetic problems.

When a patch antenna is applied to the surface of an aircraft, the problem of interlayer separation may occur due to the patch falling off due to impact during operation or friction with the air. To solve this problem, research is being conducted on designing in a sandwich shape using honeycombs, etc., using patches using conductive fibers, or adding fibers that can support the load in the thickness direction. However, when manufacturing in a sandwich shape, it is difficult to implement a thin thickness, and problems such as adhesion problems between the skin and core, and deterioration of antenna performance due to resonance depending on the cell size of the honeycomb may occur.

In addition, research is being conducted to utilize carbon fiber or copper fiber as a patch, but in this case, the composite material is not symmetrical in the thickness direction, so it bends during production, and there is a possibility of mechanical property degradation due to residual stress. If fibers are added in the thickness direction to fix the patch (stitching), the load-bearing capacity can be improved, but the production process is complicated.

One object of the present invention is to provide a structural antenna that improves the reliability of a patch antenna.

However, the problems to be solved by the present invention are not limited to the problems mentioned above, and may be expanded in various ways without departing from the spirit and scope of the present invention.

According to an exemplary embodiment of the present invention for achieving the above-described object of the present invention, a structural antenna includes a base layer, a patch antenna pattern disposed on a first surface of the base layer and including a metal-coated fiber, a via feeder penetrating the base layer and electrically connected to the patch antenna pattern, and a ground layer disposed on a second surface of the base layer opposite to the first surface.

According to one embodiment, the metal-coated fiber comprises a dielectric fiber and a conductive coating layer surrounding at least a portion of the dielectric fiber.

In one embodiment, the genetic fiber comprises glass fiber or polymer fiber.

In one embodiment, the surface resistance of the patch antenna pattern is 3Ω/sq or less.

In one embodiment, at least a portion of the patch antenna pattern is embedded in the base layer.

According to one embodiment, the patch antenna pattern is included in a fiber layer disposed on the first surface of the base layer, the fiber layer including a metal-coated region corresponding to the patch antenna pattern and a peripheral region not coated with metal.

In one embodiment, the grounding layer comprises metal-coated fibers.

In one embodiment, the via feeder comprises carbon fibers forming a fiber-matrix interface with the base layer.

In one embodiment, the patch antenna pattern comprises a nickel-coated glass fiber.

As described above, according to the exemplary embodiments of the present invention, the bonding strength between the patch antenna pattern and the base layer can be increased. Accordingly, the mechanical properties and reliability of the structural antenna including the patch antenna pattern can be increased.

FIG. 1 is a plan view illustrating an antenna according to one embodiment of the present invention.
Figure 2 is a cross-sectional view taken along line I-I' of Figure 1.
FIG. 3 is a plan view illustrating a patch antenna pattern of an antenna according to one embodiment of the present invention.
Figure 4 is a cross-sectional view taken along line II-II' of Figure 3.
FIG. 5 is a cross-sectional view of a metal-coated fiber constituting a patch antenna pattern of an antenna according to one embodiment of the present invention.
FIGS. 6 and 7 are cross-sectional views illustrating a method for manufacturing an antenna according to one embodiment of the present invention.
FIGS. 8, 9, and 10 are cross-sectional views illustrating a method for manufacturing an antenna according to one embodiment of the present invention.
FIGS. 11 and 12 are cross-sectional views illustrating antennas according to embodiments of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. The present invention can be modified in various ways and can have various forms, and thus specific embodiments will be illustrated and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, but should be understood to include all modifications, equivalents, or substitutes included in the spirit and technical scope of the present invention. In the attached drawings, the dimensions of structures are illustrated in an enlarged manner compared to actual sizes in order to ensure clarity of the present invention.

The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the terms "comprises" or "has" and the like are intended to specify the presence of a feature, number, step, operation, component or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms defined in commonly used dictionaries, such as those defined in common dictionaries, should be interpreted as having a meaning consistent with the meaning they have in the context of the relevant art, and will not be interpreted in an idealized or overly formal sense unless expressly defined in this application.

FIG. 1 is a plan view illustrating an antenna according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line II-II' of FIG. 1. FIG. 3 is a plan view illustrating a patch antenna pattern of an antenna according to an embodiment of the present invention. FIG. 4 is a cross-sectional view taken along line II-II' of FIG. 3. FIG. 5 is a cross-sectional view of metal-coated fibers constituting a patch antenna pattern of an antenna according to an embodiment of the present invention.

Referring to FIGS. 1 and 2, an antenna according to one embodiment of the present invention includes a base layer (130), a patch antenna pattern (110) disposed on a first surface (upper surface) of the base layer (110), and a via feeder (112) penetrating the base layer (110) and connected to the patch antenna pattern (110). The antenna may further include a ground layer (120) disposed on a second surface (lower surface) of the base layer (110) opposite to the first surface, and a feed member (140) disposed below the base layer (110) and connected to the via feeder (112).

According to one embodiment, the base layer (110) may include a polymer. For example, the base layer (110) may be formed by curing a prepreg including a polymer resin, such as an epoxy resin, an acrylic resin, a phenol resin, etc. The base layer (110) may function as a dielectric layer and may have an appropriate thickness depending on the required permittivity and required physical properties.

The above patch antenna pattern (110) can form a radiation pattern according to the surface current to transmit or receive an RF (Radio Frequency) signal. The structural antenna according to one embodiment of the present invention may include a plurality of patch antenna patterns (110). For example, the patch antenna pattern (110) may have a square shape and may be arranged in a matrix shape. However, the embodiments of the present invention are not limited thereto. For example, the patch antenna pattern (110) may have various shapes known to function as a patch antenna pattern, such as a rectangular shape, a circular shape, a ring shape, a triangular shape, etc.

According to one embodiment, the patch antenna pattern (110) includes a metal-coated fiber (dielectric fiber). For example, the patch antenna pattern (110) may include a metal-coated fabric made of metal-coated fiber.

Referring to FIGS. 3 and 4, the patch antenna pattern (110) may include first metal-coated fibers arranged in a first direction (D1) and second metal-coated fibers arranged in a second direction (D2) perpendicular to the first direction (D1). According to one embodiment, the first metal-coated fibers and the second metal-coated fibers may be arranged in a plurality of bundles, and each bundle may be woven with warp and weft yarns to form a metal-coated fabric.

For example, the first metal-coated fiber and the second metal-coated fiber may be dielectric fibers having a metal core. For example, each metal-coated fiber constituting the patch antenna pattern (110) may have a cross-sectional structure in which a conductive coating layer (CL) surrounds a dielectric fiber (FB), as illustrated in FIG. 5. However, embodiments of the present invention are not limited thereto, and the conductive coating layer (CL) may partially or asymmetrically surround the base fiber (FB).

For example, the dielectric fibers may include glass fibers, polymer fibers, and the like. For example, the polymer fibers may include aramid (Kevlar), nylon, polyethylene, polypropylene, polyether terephthalate, polyester, and the like. The first metal-coated fibers and the second metal-coated fibers may include the same fibers or different fibers, and may be composed of different materials within the bundle as needed.

For example, the conductive coating layer can be formed by coating a metal material on the dielectric fiber fabric by a method such as electroless plating, sputtering, chemical vapor deposition, vacuum deposition, or thermal deposition.

For example, the conductive coating layer (CL) may include iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), or an alloy thereof.

According to embodiments of the present invention, the properties of the antenna, such as the band gap, reflection loss factor, and gain, can be controlled by controlling the thickness of the conductive coating layer (CL), and for example, the surface resistance of the patch antenna pattern (110) can be 3Ω/sq or less.

The above ground layer (120) may include metal. The above ground layer (120) may have a continuous layer form, but embodiments of the present invention are not limited thereto, and the above ground layer (120) may also include metal-coated fibers like the above patch antenna pattern (110).

FIGS. 6 and 7 are cross-sectional views illustrating a method for manufacturing an antenna according to one embodiment of the present invention.

Referring to FIG. 6, a patch antenna pattern (110) including a metal-coated fiber is placed on a resin prepreg (10). The resin prepreg (10) may include a polymer resin such as an epoxy resin, an acrylic resin, a phenol resin, etc., and may further include reinforcing fibers, for example, glass fibers, impregnated in the polymer resin.

Referring to FIG. 7, the resin prepreg (10) on which the patch antenna pattern (110) is arranged is cured to form a base layer (130). For example, the resin prepreg (10) may be cured by heating and pressurizing the resin prepreg (10) using a device such as an autoclave. In the process of forming the base layer (130), the resin of the prepreg (10) may penetrate between the fibers of the patch antenna pattern (110) by heating/pressurizing. Therefore, the bonding strength between the patch antenna pattern (110) and the base layer (130) may be increased.

Next, a ground layer may be formed on the lower surface of the base layer (130) by a method such as lamination, deposition, or plating, and a via feeder penetrating the base layer (130) may be formed. The via feeder may be formed before or after forming the ground layer.

In another embodiment, when the ground layer includes dielectric fibers, a curing process may be performed after metal-coated fibers are placed on the upper and lower surfaces of the resin prepreg.

FIGS. 8, 9, and 10 are cross-sectional views illustrating a method for manufacturing an antenna according to one embodiment of the present invention. According to one embodiment, a via feeder can be formed using carbon fiber.

Referring to Fig. 8, carbon fibers (20) are penetrated through the resin prepreg (10) in the thickness direction.

In order to penetrate the carbon fiber (20) through the resin prepreg (10), a needle (30) may be used. For example, after fixing one end of the carbon fiber (20) to the needle (30), the needle (30) may be penetrated through the resin prepreg (10), and then pulled so that the carbon fiber (20) may penetrate the resin prepreg (10) following the needle (30).

Referring to Fig. 9, the carbon fiber (20) penetrating the resin prepreg (10) is cut to separate the portion embedded in the resin prepreg (10).

Referring to FIG. 10, a patch antenna pattern (110) including a metal-coated fiber is placed on a resin prepreg (10) into which carbon fibers are inserted, and the resin prepreg (10) is cured to form a base layer (130) having a via feeder (112) made of carbon fibers. For example, the resin prepreg (10) can be cured by heating and pressurizing the resin prepreg (10) using a device such as an autoclave.

Next, a ground layer is formed on the lower surface of the base layer (130) by a method such as lamination, deposition, or plating.

This configuration can prevent the patch antenna pattern (110) from being damaged when forming a feeder hole by forming a via feeder by inserting carbon fiber in a pre-leg state before forming the base layer of the antenna, and can improve the physical properties of the structural antenna by forming the via feeder at the fiber-matrix interface with the base layer.

FIGS. 11 and 12 are cross-sectional views illustrating antennas according to embodiments of the present invention.

Referring to FIG. 11, at least a portion of the patch antenna pattern (110) may have a form embedded in the base layer (130). This configuration may be obtained by laminating the patch antenna pattern (110) on a prepreg including a resin forming the base layer (130), and then pressurizing/heating it, and as the patch antenna pattern (110) is embedded in the base layer (130), the adhesive strength may be improved.

Referring to FIG. 12, an antenna according to one embodiment includes a metal coating region (210a) corresponding to a patch antenna pattern and a fiber layer (210) coupled to a base layer (130). The fiber layer (210) may have a fabric structure of a dielectric fiber as a whole and may include a metal coating region (210a) coated with metal and a peripheral region (210b) not coated with metal. The metal coating region (210a) may be electrically connected to a via feeder (112) and may function as a patch antenna pattern. The peripheral region (210b) may be coupled with the base layer (130) to increase the adhesive strength of the patch antenna pattern.

For example, the fiber layer (210) can be obtained by selectively depositing or coating a metal on the dielectric fabric through a mask, screen, etc. Alternatively, the fiber layer (210) can be obtained by coating the dielectric fabric with metal throughout and then removing (etching) the metal coating from a portion except for the patch antenna pattern region.

Below, the performance of the structural antenna according to an embodiment of the present invention will be verified through simulation and experiment.

simulation

In order to analyze the characteristics of the structural antenna according to an embodiment of the present invention, an antenna operating at 3 GHz was designed (patch length: 21 mm, patch width: 28 mm, distance between patch center and via feeder: 8 mm, distance between patch and ground layer: 3.2 mm), and the reflection loss and gain of the antenna were confirmed by changing the resistance (sheet resistance) of the ground plane and the patch by dividing the case where the ground plane is a perfect conducting (PEC) and the case where it is a metal-coated fiber.

Example 1

After nickel was coated on glass fibers through electroless plating, a patch shape was fabricated through fiber cutting (same as the simulation design). The obtained patch antenna pattern was laminated with an epoxy-glass fiber prepreg (total thickness of approximately 3 mm), and cured in an autoclave device (130°C, 6 bar, 2 hours) to form a base layer combined with the patch antenna pattern. Next, a ground layer was formed using a copper tape to prepare an antenna sample.

The bandgap, reflection loss, and gain of the above simulation and structural antenna of Example 1 are shown in Table 1 below.

Referring to Table 1 showing the simulation results and the measurement results of Example 1, it can be seen that the structural antenna of the present invention has usable antenna performance.

Additionally, additional experiments were conducted to verify the adhesion of the patch antenna pattern.

Figure 13 is a graph showing the interlaminar shear strength (ILSS) of a laminate obtained by placing copper foil (Copper), glass fiber (Glass), and nickel-coated glass fiber (Ni-Glass) of the same size between two epoxy-glass fiber prepregs and curing them through an autoclave process.

Referring to FIG. 13, it can be seen that when nickel-coated glass fiber is used, the bonding strength between the patch antenna pattern and the base layer can be significantly increased compared to when a conventional metal foil is used.

Although the present invention has been described above with reference to embodiments thereof, it will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below.

The structural antenna according to the exemplary embodiments described above can be used in various industrial fields that utilize antennas, such as aircraft, ships, etc.

Claims (9)

A base layer comprising a polymer resin;
A patch antenna pattern having a fabric structure including metal-coated fibers and disposed on the first surface of the base layer;
A via feeder electrically connected to the patch antenna pattern through the base layer; and
Including a ground layer disposed on the second side of the base layer opposite to the first side,
A structural antenna characterized in that the patch antenna pattern is embedded in the base layer, and the upper surface of the patch antenna pattern and the first surface of the base layer adjacent to the patch antenna pattern form a flat surface that is continuously connected. A structural antenna in accordance with claim 1, wherein the metal-coated fiber comprises a dielectric fiber and a conductive coating layer surrounding at least a portion of the dielectric fiber. A structural antenna, characterized in that in the second paragraph, the dielectric fiber comprises glass fiber or polymer fiber. A structural antenna, characterized in that in the second paragraph, the surface resistance of the patch antenna pattern is 3Ω/sq or less. delete delete A structural antenna, characterized in that in claim 1, the ground layer includes a metal-coated fiber. A structural antenna, characterized in that in claim 1, the via feeder includes carbon fibers forming a fiber-matrix interface with the base layer. A structural antenna in accordance with claim 1, wherein the patch antenna pattern comprises a nickel-coated glass fiber.

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