KR20090028355A - Single feed wideband circular polarized patch antenna - Google Patents

Abstract

A broadband circular polarization patch antenna can improve the axial ratio bandwidth of the circular polarization by forming the upper patch on the one side of the lower part patch. The connector(170) is connected to one side of the earth plate(180). The dielectric substrate(110) is laminated on the other side of the earth plate. The lower part patch(130) of hexagon is laminated on one side of the dielectric substrate. Hole is formed in the lower part patch. The feeding point is formed inside hole. The single feeding probe(160) connects the feeding point and connector. The upper patch(120) of hexagon is laminated on one side of the lower part patch.

Description

Single feed wideband circular polarized patch antenna

The present invention relates to a wideband patch antenna, and more particularly, to a single-feed broadband patch antenna that generates circular polarization.

The patch antenna is not only compact in size but also has a light weight, a simple manufacturing process, and a low cost. However, such a patch antenna has a disadvantage that it is difficult to widen the bandwidth (Band width), it is difficult to use in the high frequency band because inducing a lot of coupling loss (Coupling loss).

Recently, researches for overcoming the disadvantages of the patch antenna have been actively conducted. For example, as a technology for widening a bandwidth of a patch antenna, a technology in which a 'L' shaped probe is used and a technique in which a 'U' shaped slot is formed is used. have. Moreover, as a technique for improving the axial ratio which is one of the indexes which show the polarization characteristic of an antenna, there exists a technique in which a coplanar probe is used.

Although the bandwidth of the patch antenna is widened by the above-described techniques, the fabrication process for implementing the patch antenna is more complicated. In addition, as the manufacturing process is complicated, there is a problem that the manufacturing cost for producing a patch antenna is significantly increased.

The present invention is to provide a single-feed broadband circular polarized patch antenna with a simple manufacturing process.

In addition, the present invention is to provide a single-feed broadband circular polarization patch antenna with low manufacturing cost.

According to an aspect of the present invention, a connector; A ground plate to which the connector is connected; A dielectric substrate stacked on the other surface of the ground plate; Perforations are formed, a feed point is formed inside the perforations, and hexagonal lower patches stacked on one surface of the dielectric substrate; A single feed probe connected to the feed point and connected to the connector through the dielectric substrate and the ground plate; And a hexagonal upper patch stacked on one surface of the lower patch.

Here, the dielectric substrate may be an FR-4 substrate.

In addition, the thickness of the dielectric substrate may be 1.6 [mm].

In addition, the upper patch is formed by cutting a triangular patch portion including two vertices symmetrical with respect to a diagonal line in a square patch, and the triangle may be a right isosceles triangle.

In addition, the square may have a length of 19 [mm] on one side, and the triangle may have a length of 7.5 [mm] on the short side.

In addition, the lower patch is formed by cutting each of the triangular patch portions including two vertices symmetrical with respect to the diagonal in a square patch, the triangle may be a right isosceles triangle.

The square may have a length of one side of 16 [mm], and the triangle may have a short side of 6.5 [mm].

In addition, the perforation may be formed in a square having a side length of 3 [mm].

In addition, the feed point may be a square patch having a side length of 2 [mm].

In addition, the single feed probe may be a coaxial probe having a resistance of 50 [ohm].

In addition, the dielectric substrate may be stacked with a predetermined distance from the ground plate.

In addition, the distance between the dielectric substrate and the ground plate may be 3 [mm].

In addition, the upper patch may be stacked with a predetermined distance from the lower patch.

In addition, the distance between the upper patch and the lower patch may be 3.8 [mm].

According to the present invention, it is possible to provide a single-feed broadband circular polarization patch antenna having a simple manufacturing process.

In addition, according to the present invention can provide a single-feed broadband circular polarized patch antenna of low manufacturing cost.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all transformations, equivalents, and substitutes included in the spirit and scope of the present invention. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic side view of a single-feed broadband circular polarization patch antenna according to an embodiment of the present invention, FIG. 2 is a schematic plan view of an upper patch according to an embodiment of the present invention, and FIG. 3 is one of the present invention. A schematic plan view of a lower patch according to an embodiment. Hereinafter, a single-feed broadband circular polarization patch antenna 100 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3 (but the unit is [mm]).

1, the single-feed broadband circular polarization patch antenna 100 according to an embodiment of the present invention is a dielectric substrate 110, the upper patch 120, the lower patch 130, the first air layer 140, The second air layer 150 includes a single feed probe 160, a connector 170, and a ground plate 180. First, the appearance of the single-feed broadband circularly polarized patch antenna 100 will be described. However, it is assumed that the Z-axis direction of FIG. 1 is in the upper direction.

The single-feed broadband circularly polarized patch antenna 110 is a structure in which the dielectric substrate 110, the ground plate 180, and / or one or more patches are stacked. In FIG. 1, two patches (that is, the upper patch 120 and the lower patch) are illustrated. Single-feed broadband circularly polarized patch antenna 100 in which patches 130 are stacked is illustrated. That is, the dielectric substrate 110 may be formed with a predetermined distance H1 spaced apart from the plane of the ground plate 180. Therefore, the first air layer 140 may exist between the plane of the ground plate 180 and the bottom surface of the dielectric substrate 110. In addition, the connector 170 may be connected to the bottom surface of the ground plate 180. In addition, a lower patch 130 may be stacked on the plane of the dielectric substrate 110. In this case, a single feed probe 160 may be connected to a bottom surface of the lower patch 130, and the single feed probe 160 may be connected to the connector 170 through the dielectric substrate 110 and the ground plate 170. . In addition, the upper patch 120 may be formed to be spaced apart from the plane of the lower patch 130 by a predetermined distance (H3).

Here, the axial ratio bandwidth of the circular polarization (CP) may be improved (that is, wider) due to the presence of the upper patch 120. This will be described later with reference to FIG. 5.

Here, as a material of the dielectric substrate 110, 'FR-4', which is relatively inexpensive, may be used. Of course, the material of the dielectric substrate 110 is not limited thereto, and epoxy, duroid, Teflon, bakelite, high resistance silicon, glass, alumina, LTCC and air form May be used. As the material of the dielectric substrate 110 according to the present embodiment, an FR-4 substrate having a thickness H2 of 1.6 [mm] and a relative permittivity of 4.4 was used. In addition, the thickness H1 of the first air layer 140 according to the present embodiment is 3 [mm], and the thickness H3 of the second air layer 150 is 3.8 [mm]. In addition, the connector 170 according to the present embodiment used an SMA connector. Of course, it is obvious that the thickness and specific transmittance of the dielectric substrate are not limited thereto.

In addition, the single feed probe 160 according to the present embodiment used a coaxial probe (Coaxial probe) having a resistance of 50 [ohm]. The single feed probe 160, which is a coaxial probe, has inductive impedance. As a result, the single-feed broadband circular polarization patch antenna 100 has one or more air layers (ie, the first air layer 140, the second air layer 150, etc.) to compensate for this. That is, since the impedance of the single-feed broadband circular polarization patch antenna 100 or the impedance matching at the input terminal is difficult due to the inductive impedance of the single feed probe 160, the single feed broadband The circularly polarized patch antenna 100 may include a first air layer 140, a second air layer 150, and the like to compensate the induced impedance of the single feed probe 160.

Although the upper patch 120 is shown as floating in the air, substantially the upper patch may be supported by a separate support. For example, a support for supporting the upper patch 120 may exist in a case in which the single-feed broadband circular polarization patch antenna 100 is mounted, whereby the upper patch 120 may be supported. .

Referring to FIG. 2, the upper patch 120 according to an embodiment of the present invention is a patch of a hexagon, and is formed by cutting a triangular patch portion including two vertices symmetrically based on a diagonal line in a square patch. Can be. In this case, the square patch may have a length of one side L1, and the two triangular patch portions may be patch portions of a right-sided isosceles triangle having a length of L2 (L1> L2). In this embodiment, an upper patch 120 with L1 of 19 [mm] and L2 of 7.5 [mm] was used.

Referring to FIG. 3, the lower patch 130 according to an embodiment of the present invention is a patch of a hexagon, and, like the upper patch 120, includes two vertices symmetric about a diagonal line in a square patch. The triangular patch portions can be formed by cutting each. In this case, the square patch may have a length of one side of L3, and the two triangular patch portions may be patch portions of a right-sided isosceles triangle having a length of L4 (L3> L4). In this embodiment, a lower patch 130 with L3 of 16 [mm] and L4 of 6.5 [mm] was used.

In addition, a square perforation 320 may be formed in the lower patch 130, and a feed point 310 having a smaller size than that of the perforation 320 may be formed in the perforation 320. . In this case, the size of one side of the perforation 320 may be W1. In addition, the feed point 310 may be a square patch, the size of one side may be W2 (W1> W2). In this embodiment, a perforation 320 having a W1 of 3 [mm] was used, and a feed point 310 having a W2 of 2 [mm] was used.

In addition, the center point of the feed point 310 may be spaced apart by the Lf in the direction perpendicular to the side positioned at the bottom with respect to the X axis of the six outer sides of the lower patch 130 (see FIG. 3). At this time, Lf was set to 3.5 [mm] in this embodiment.

Here, although the exact dimensions of each component of the single-feed broadband circularly polarized patch antenna 100 are illustrated, this is only an example. Accordingly, the dimensions illustrated herein do not limit the scope of the invention.

As described above, the single-feed broadband circularly polarized patch antenna 100 according to the present invention has a simple structure, so the manufacturing process is simple, and thus the manufacturing cost can be reduced.

4 is a view showing a measurement result of the return loss of the electrical characteristics of the single-feed broadband circular polarization patch antenna according to an embodiment of the present invention, Figure 5 is a single-feed broadband circular polarization patch antenna according to an embodiment of the present invention The measurement result of the axial ratio and the gain which are the electrical characteristics of is shown.

Hereinafter, the electrical characteristic measurement results of the single-feed broadband circularly polarized patch antenna 100 will be described with reference to FIGS. 4 and 5. Here, the reflection loss means that if there is a mismatch of the impedance of the antenna, power is reflected at a frequency where the mismatch exists, and a part of the incident power becomes the reflected power, which means a ratio of the incident power and the reflected power. That is, the return loss may be used as an index indicating how well the impedance matching is performed at the input terminal.

The axial ratio is one of the indexes indicating the polarization characteristics of the antenna, and is a ratio between the electric field strength in the major axis direction of the elliptic polarization and the electric field strength in the minor axis direction. Thus, a complete circular polarization has an axial ratio of '1'. In addition, the axial ratio of complete linear polarization becomes infinity. In addition, the gain is an index indicating how much the reflection shape is concentrated in a specific direction compared to an isotropic antenna in which electromagnetic waves are reflected in all directions.

In this case, the electrical characteristics such as the return loss result, the axial ratio measurement result, and / or the gain result of the single-feed broadband circular polarization patch antenna 100 may be simulated by Ansoft HFSS software, such as return loss. Electrical characteristics of the single-feed broadband circularly polarized patch antenna 100 were measured using an HP 8720C network analyzer.

Referring to FIG. 4, when the standing voltage ratio (VSWR, Voltage Standing Wave Ratio) is 2 or less, the measured second impedance bandwidth is 4380 [MHz] (that is, 4.42 [GHZ] to 8.80 [GHz]). (66.26 [%]). Also, when the standing wave ratio is 1.5 or less, the first measured impedance bandwidth is 1815 [MHz] (that is, between 4.49 [GHZ] to 6.805 [GHz]) (30.78%).

In other words, the single-feed broadband circular polarization patch antenna 100 has the smallest return loss in the frequency band (between 5.15 [GHz] and 5.825 [GHz]) of 5 [GHz] WLAN (WLAN), so that the impedance matching is excellent. have.

Referring to FIG. 5, it can be seen that when the axis ratio of the single-feed broadband circular polarization patch antenna 100 is 3 or less, the bandwidth is 1210 [MHz] (that is, between 4.98 [GHz] and 6.10 [GHz]). . Accordingly, it can be seen that the single-feed broadband circular polarization patch antenna 100 generates a near circular circular polarization in the frequency band (between 5.25 [GHz] and 5.825 [GHz]) of 5 [GHz] wireless LAN (WLAN).

In addition, it can be seen that the gain of the single-feed broadband circular polarization patch antenna 100 is 7.6 [dBi] in the frequency band of 5 [GHz] WLAN.

That is, the single-feed broadband circular polarization patch antenna 100 can confirm that the ratio and / or gain is excellent in the frequency band of 5 [GHz] WLAN.

In this case, the electrical characteristics such as the return loss result, the axial ratio measurement result, and / or the gain result of the single-feed broadband circular polarization patch antenna 100 may be simulated by Ansoft HFSS software, such as return loss. Electrical characteristics of the single-feed broadband circularly polarized patch antenna 100 were measured using an HP 8720C network analyzer.

6 is a diagram showing the radiation characteristics at each frequency of a single-feed broadband circularly polarized patch antenna according to an embodiment of the present invention.

Referring to FIG. 6, an azimuth plane showing radiation characteristics at 5.2 [GHz], 5.3 [GHz], and 5.775 [GHz], which are frequencies included in a frequency band of 5 [GHz] WLAN, is shown.

Referring to FIG. 6, the single-feed broadband circular polarization patch antenna 100 is the same or similar at frequencies 5.2, GHz, 5.3 and 5.775 GHz, respectively, which are frequencies included in a frequency band of 5 [GHz] WLAN. It can be seen that the radiation characteristics.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art to which the present invention pertains without departing from the spirit and scope of the present invention as set forth in the claims below It will be appreciated that modifications and variations can be made.

1 is a schematic side view of a wideband patch antenna according to an embodiment of the present invention.

2 is a schematic plan view of an upper patch according to an embodiment of the present invention.

3 is a schematic plan view of a lower patch according to an embodiment of the present invention.

4 is a view showing a measurement result of the return loss which is an electrical characteristic of the broadband patch antenna according to an embodiment of the present invention.

5 is a view showing a measurement result of the axial ratio and the gain of the electrical characteristics of the broadband patch antenna according to an embodiment of the present invention.

6 is a diagram showing the radiation characteristics at each frequency of the broadband patch antenna according to an embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

100: single-feed broadband circularly polarized patch antenna.

110: dielectric substrate

120: upper patch

130: lower patch

140: first air layer

150: second air layer

160: single feed probe

170: connector

180: ground plate

Claims (14)

A connector; A ground plate to which the connector is connected; A dielectric substrate stacked on the other surface of the ground plate; Perforations are formed, a feed point is formed inside the perforations, and hexagonal lower patches stacked on one surface of the dielectric substrate; A single feed probe connecting the feed point and the connector; And Single-feed broadband circular polarization patch antenna comprising a hexagonal upper patch laminated on one surface of the lower patch. The method of claim 1, The dielectric substrate is a single-feed broadband circular polarization patch antenna, characterized in that the FR-4 substrate. The method of claim 2, Single-feed broadband circularly polarized patch antenna, characterized in that the thickness of the dielectric substrate is 1.6 [mm]. The method of claim 1, The upper patch is formed by cutting each of the triangular patch portions including two vertices symmetric about a diagonal line in a square patch, Wherein said triangle is a right-angled isosceles triangle. The method of claim 4, wherein The square is a single-feed broadband circular polarized patch antenna, characterized in that the length of one side is 19 [mm], the triangle is 7.5 [mm] in length of the short side. The method of claim 1, The lower patch is formed by cutting each of the triangular patch portions including two vertices symmetric about a diagonal line in a square patch, Wherein said triangle is a right-angled isosceles triangle. The method of claim 6, The square is a single-feed broadband circular polarization patch antenna, characterized in that the length of one side is 16 [mm], the triangle is 6.5 [mm] in length. The method of claim 1, The perforation is a single-feed broadband circular polarized patch antenna, characterized in that formed in a square having a side length of 3 [mm]. The method of claim 1, The feed point is a single-feed broadband circular polarization patch antenna, characterized in that the square patch of the side length of 2 [mm]. The method of claim 1, Wherein said single feed probe is a coaxial probe having a resistance of 50 ohms. The method of claim 1, And the dielectric substrate is stacked with the ground plate at a predetermined distance. The method of claim 11, And a distance between the dielectric substrate and the ground plate is 3 [mm]. The method of claim 1, And the upper patch is stacked with the lower patch at a predetermined interval. The method of claim 13, Single-feed broadband circularly polarized patch antenna, characterized in that the interval between the upper patch and the lower patch is 3.8 [mm].

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