A small indoor directional antenna

Abstract

This invention discloses a small indoor directional antenna, comprising an antenna radiating body and a feed body. The antenna radiating body has an inner octagonal rectangular slot, and the feed body is located within the area of ​​the inner octagonal rectangular slot. The top two corners of the feed body are formed with beveled stepped portions, and a cross-shaped groove is formed at the center of the feed body. The antenna radiating body has a feed port for connecting a microstrip feed line extending from the bottom of the feed body to the periphery of the inner octagonal rectangular slot.

Description

Technical Field

[0001] This invention relates to the technical field of wireless communication systems, and in particular to a small indoor directional antenna. Background Technology

[0002] According to the 3GPP standard, 5G frequency bands are divided into two ranges: FR1 and FR2. The FR1 band ranges from 450MHz to 6GHz, while the FR2 band ranges from 24.25GHz to 52.6GHz. However, due to the longer wavelength of the 608-960MHz band, antennas in this band are large and difficult to meet the requirements of installation platforms. The antenna will become the bulkiest component in the system, thus necessitating the development of various small antennas compatible with miniaturized devices. Therefore, researching miniaturized, low-profile antennas is essential.

[0003] In current research, miniaturized, low-profile antennas are mainly achieved by extending the current path on the antenna surface. The main methods are bending and slotting, each with its own advantages and disadvantages.

[0004] 1) When miniaturization is required to achieve lower frequency bands, more bending will be required. However, a large part of the current in the bent antenna part is out of phase and will cancel each other out, thus reducing the bandwidth.

[0005] 2) Slotting involves creating grooves perpendicular to the current direction in non-radiating areas of the antenna, thereby increasing the current path length. However, this increases the current perpendicular to the original current, thus increasing the antenna's cross-polarization level and reducing its performance.

[0006] Therefore, how to achieve miniaturized indoor antennas is a pressing technical challenge that needs to be addressed, especially how to overcome the drawbacks of bending and slotting methods. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide an indoor directional antenna that achieves broadband miniaturization of the antenna while ensuring that the antenna area and radiation performance remain unchanged.

[0008] To achieve the above objectives, the present invention provides a small indoor directional antenna, comprising an antenna radiating body and a feed body. The antenna radiating body has an inner octagonal rectangular slot, and the feed body is located within the area of ​​the inner octagonal rectangular slot. The top two corners of the feed body are formed with beveled stepped portions, and a cross-shaped groove is formed at the center of the feed body. The antenna radiating body is provided with a feed port for connecting a microstrip feed line extending from the bottom of the feed body to the periphery of the inner octagonal rectangular slot.

[0009] Furthermore, the antenna radiating body has symmetrically arranged "L"-shaped defects formed on both sides of the microstrip feed line.

[0010] Furthermore, it also includes three semi-annular narrow strip patches offset from the inside out at the top of the inner octagonal rectangular groove, wherein the lengths of the three semi-annular narrow strip patches are different, and the lengths of the three semi-annular narrow strip patches increase sequentially from the inside out.

[0011] Furthermore, it also includes two symmetrically arranged narrow strip patches within the inner octagonal rectangular groove, wherein the two narrow strip patches are respectively connected to two symmetrically arranged corner positions of the innermost semi-circular narrow strip patch.

[0012] Furthermore, the length of any of the aforementioned semi-annular narrowband patches is equal to one-quarter of the wavelength of the corresponding frequency band.

[0013] Furthermore, the antenna radiating body is rectangular in shape.

[0014] Furthermore, the centerline of the feed body is collinear with and coincides with the centerline of the antenna radiating body.

[0015] The present invention adopts the above-mentioned solution, and its beneficial effects are as follows: without affecting the radiation performance and size of the original broadband antenna, the operating frequency of the antenna is broadened, and the miniaturization of the patch antenna is realized, making it more suitable for various scenarios. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a small indoor directional antenna.

[0017] Figure 2 The S-parameter plot is for a device that does not contain three semi-circular narrow-band patches.

[0018] Figure 3 This is an S-parameter plot containing a semi-circular narrowband patch.

[0019] Figure 4 The current diagram for a 0.65 GHz circuit containing a semi-circular narrowband patch is shown.

[0020] Figure 5 The current diagram for 0.8 GHz containing a semi-circular narrowband patch is shown.

[0021] Figure 6 This is an S-parameter diagram containing semi-circular narrowband patches and strip narrowband patches.

[0022] Figure 7 The current diagram for 0.8 GHz includes semi-circular narrowband patches and strip narrowband patches.

[0023] Among them, 1-antenna radiating body, 11-inner octagonal rectangular slot, 12-feed port, 13-"L"-shaped defect ground, 2-feed body, 21-beveled stepped section, 22-cross-shaped groove, 23-microstrip feed line, 3-semi-annular narrowband patch, 4-strip narrowband patch. Implementation

[0024] To facilitate understanding of the present invention, a more complete description is given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided so that this disclosure will be thorough and complete.

[0025] See appendix Figure 1-5 As shown, in this embodiment, a small indoor directional antenna includes an antenna radiating body 1 and a feeding body 2. The antenna radiating body 1 has an inner octagonal rectangular slot 11. The inner octagonal rectangular slot 11 has a symmetrical structure, and the lengths of each side on one side are different. For ease of explanation, taking one side of the inner octagonal rectangular slot 11 as an example, the sides are defined as L1, L2, L3 and L4 from top to bottom. That is, the top side L1 is horizontally arranged, the side L2 is inclined, the side L3 is vertically arranged, and the side L4 is inclined.

[0026] In this embodiment, the power supply body 2 is located within the area of ​​the inner octagonal rectangular slot 11. Specifically, the power supply body 2 is arranged near the bottom of the inner octagonal rectangular slot 11 (i.e., near the edge L4). The top two corners of the power supply body 2 are formed with beveled stepped portions 21, which are multi-layered stepped structures arranged at an angle. Furthermore, a cross-shaped groove 22 is provided at the center of the power supply body 2, wherein the width of the horizontal segment of the cross-shaped groove 22 is greater than the width of the vertical segment.

[0027] In this embodiment, the antenna radiating body 1 is provided with a feed port 12 for connecting the microstrip feed line 23 extending from the bottom of the feed body 2 to the periphery of the inner octagonal rectangular slot 11. Specifically, the feed port 12 is arranged near the bottom end of the antenna radiating body 1. The microstrip feed line 23 has a strip-shaped structure.

[0028] Furthermore, the centerline of the feed body 2 is collinear with the centerline of the antenna radiating body 1, wherein the microstrip feed line 23 extends along the centerline direction of the feed body 2.

[0029] In this embodiment, the antenna radiating body 1 has symmetrically arranged "L"-shaped defect grounds 13 formed on both sides of the microstrip feed line 23.

[0030] Thus, by combining the aforementioned beveled stepped portion 21 and cross-shaped groove 22 of the feed section with the "L"-shaped defect ground 13 of the antenna radiating body 1, the radiation frequency band of the indoor directional antenna can be covered to 1.7-6GHz, achieving the effect of miniaturization and wide coverage.

[0031] In this embodiment, to enable the indoor directional antenna to have radiation characteristics in the 0.609-0.96 GHz frequency band, it further includes three semi-annular narrowband patches 3 offset from the inside out at the top of the inner octagonal rectangular slot 11. The three semi-annular narrowband patches 3 have different lengths, and their lengths increase sequentially from the inside out. This forms a resonant point in the low-frequency band, thereby achieving a spread spectrum effect without affecting the overall size.

[0032] In this embodiment, the length of any of the semi-circular narrowband patches 3 is equal to one-quarter of the wavelength of the corresponding frequency band. For example, the outermost semi-circular narrowband patch 3 corresponds to 0.65 GHz, which corresponds to a wavelength of 461.2 mm, and the sum of the lengths of its sides is 115.3 mm (length equal to one-quarter of the wavelength).

[0033] For ease of understanding, the following comparison is made between an indoor directional antenna without the three semi-circular narrowband patches 3 and the indoor directional antenna with the three semi-circular narrowband patches 3 described in this embodiment. Specifically, see the appendix. Figure 2 The S-parameter diagram shown does not contain the three semi-circular narrow band patches 3, and see the appendix. Figure 3 The S-parameter diagrams shown below, which contain the semi-circular narrowband patch 3, demonstrate that by adding three semi-circular narrowband patches 3, the resonant points at 0.6 / 0.7 / 0.9 GHz can be increased, thus achieving a spread spectrum effect.

[0034] Secondly, see appendix Figure 3 In the S-parameter plot showing the semi-circular narrowband patch 3, a jump point appears at 0.8 GHz; therefore, see Appendix Figure 4 and 5 As shown in the 0.65GHz and 0.8GHz current graphs, the main reason for the jump points is that the bending structure of the semi-annular narrowband patch 3 causes a large portion of the current in the bent section to be out of phase and cancel each other out, resulting in a reduction in bandwidth. To address this issue, this embodiment also includes two strip-shaped narrowband patches 4 symmetrically arranged within the inner octagonal rectangular slot 11. These two strip-shaped narrowband patches 4 are respectively connected to two symmetrically arranged corner positions of the innermost semi-annular narrowband patch 3. Adding the strip-shaped narrowband patches 4 reduces the current coupling effect between adjacent frequency bands.

[0035] In summary, please refer to the appendix. Figure 6The S-parameter diagram showing the semi-circular narrow-band patch 3 and the strip-shaped narrow-band patch 4 is shown in the attached diagram. Figure 7 As shown in the 0.8 GHz current diagram containing the semi-circular narrowband patch 3 and the strip narrowband patch 4, by adding the strip narrowband patch 4, current can flow through the second semi-circular narrowband patch 3 located in the middle, thus forming a resonant point at 0.8 GHz. This reduces the mutual influence of current between different semi-circular narrowband patches 3, and ultimately achieves an ultra-wideband effect with S-parameters less than -6 dB in the 0.609-0.96 GHz range and S-parameters less than -10 dB in the 1.7-6 GHz band.

[0036] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Any modifications or variations made by those skilled in the art, without departing from the scope of the present invention, using the disclosed technical content, are equivalent embodiments of the present invention. Therefore, all equivalent changes made based on the concept of the present invention without departing from the scope of the present invention should be covered within the protection scope of the present invention.

Claims

1. A small indoor directional antenna, characterized in that: The device includes an antenna radiating body (1) and a feed body (2). The antenna radiating body (1) has an inner octagonal rectangular slot (11). The feed body (2) is located within the area of ​​the inner octagonal rectangular slot (11). The top two corners of the feed body (2) are formed with beveled stepped portions (21), and a cross-shaped groove (22) is formed at the center of the feed body (2). The antenna radiating body (1) has a feed port (12) connected to a microstrip feed line (23) extending from the bottom of the feed body (2) to the periphery of the inner octagonal rectangular slot (11). The microstrip feed (23) has symmetrically arranged "L"-shaped defects (13) on both sides; it also includes three semi-annular narrow strip patches (3) offset from the inside to the outside at the top of the inner octagonal rectangular groove (11), wherein the lengths of the three semi-annular narrow strip patches (3) are different, and the lengths of the three semi-annular narrow strip patches (3) increase sequentially from the inside to the outside; it also includes two strip narrow strip patches (4) symmetrically arranged in the inner octagonal rectangular groove (11), wherein the two strip narrow strip patches (4) are respectively connected to two symmetrically arranged corner positions of the innermost semi-annular narrow strip patch (3).

2. A small indoor directional antenna according to claim 1, characterized in that: The length of any of the semi-circular narrowband patches (3) is equal to one-quarter of the wavelength of the corresponding frequency band.

3. A small indoor directional antenna according to claim 1, characterized in that: The antenna radiating body (1) is rectangular in shape.

4. A small indoor directional antenna according to claim 1, characterized in that: The centerline of the feed body (2) is collinear with the centerline of the antenna radiating body (1).

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