Multiband antenna of Internet of Things

Abstract

The utility model provides an Internet of Things multiband antenna, which is characterized in that the Internet of Things multiband antenna comprises a cylindrical shell, and a vibration source antenna and a resonant cavity structure which are assembled in the cylindrical shell; the vibration source antenna comprises a circular dielectric substrate, a feed source located on the lower surface of the substrate and a coupling radiation unit located on the upper surface of the substrate. The resonant cavity structure comprises a first dielectric layer, a second dielectric layer and a reflecting layer from top to bottom, and the layers are separated by specific distances through air layers. The vibration source antenna is located between the second dielectric layer and the reflecting layer. According to the utility model, through introducing the structure of the vibration source antenna and the adjustable resonant cavity, effective antenna radiation in multiple frequency bands is realized. Moreover, the structure can adjust the working frequency band through simple operation during application.

Description

Technical Field

[0001] This utility model relates to the field of antennas, and more particularly to multi-band antennas used in the Internet of Things (IoT) field. Background Technology

[0002] Many IoT sensors in industries such as industry, agriculture, environmental monitoring, and transportation rely on mobile communication networks to transmit business data and remote control information. Future mobile communication will consist of a three-dimensional wireless network comprised of 4G / 5G terrestrial mobile networks, non-terrestrial networks (NTN), and satellite. These different types of communication networks operate on different frequency bands, and even within the same standard, such as 5G mobile networks, different operators operate on different frequency bands. For example, China Telecom's 5G mobile network may be deployed in the 3.5GHz band, while China Mobile's 5G mobile network is primarily deployed in the 2.6GHz band. To achieve efficient and low-cost data transmission, IoT terminal devices require multi-band antennas to simultaneously cover these frequency bands, ensuring ease of deployment and universality, reducing costs, improving reliability, and minimizing mutual interference. Previous industry solutions typically integrated antennas from different frequency bands, increasing costs and the complexity of IoT terminal design, thus impacting deployment convenience. Various multi-band antenna designs have been proposed in the field of antenna design, but they are usually complex in structure, have low gain, and their operating parameters such as operating frequency band, bandwidth and gain are fixed and cannot be adjusted according to the application scenario.

[0003] This invention addresses current market demands by proposing a multi-band antenna for the Internet of Things (IoT). By introducing a source antenna with an adjustable resonant cavity, it achieves effective antenna radiation across multiple frequency bands. Furthermore, the operating frequency can be easily adjusted during application. It offers advantages such as low cost and universal deployment. Utility Model Content

[0004] This invention proposes a multi-band antenna for the Internet of Things, comprising a cylindrical shell and a source antenna and a resonant cavity structure assembled inside it; wherein, the source antenna includes a circular dielectric substrate, a feed source located on the lower surface of the substrate and a coupling radiation unit on the upper surface; the resonant cavity structure includes a three-layer structure from top to bottom: a first dielectric layer, a second dielectric layer and a reflective layer, with air layers separating each layer at a specific distance; the source antenna is located between the second dielectric layer and the reflective layer.

[0005] The first and second dielectric layers are circular low-loss dielectric substrates; the reflective layer is a circular PCB board with its entire upper surface covered in copper.

[0006] The feed source and coupled radiation unit are thin metal layers with specific geometries that are processed on the substrate using a printing process.

[0007] The feed source is an electric dipole structure, and the coupled radiation unit is a hexagonal split ring structure arranged in a honeycomb pattern.

[0008] The feed source is powered through a coaxial connector; an external antenna connector is mounted on the bottom of the housing and connected to the coaxial connector via an RF cable; there is a through hole in the reflective layer at the position corresponding to the external antenna connector for the RF cable to pass through.

[0009] The top opening of the outer shell is flush with the upper surface of the first medium layer and the upper edge of the outer shell, and the joint between the two is filled with waterproof sealant.

[0010] The first dielectric layer, the second dielectric layer, the source antenna, and the reflector layer are each fixed at different heights inside the outer shell by four assembly components; the four assembly components of each layer are located on the same horizontal plane and are evenly distributed along the circumference of the inner wall of the outer shell.

[0011] The back of the assembly structure is arc-shaped with positioning protrusions at both ends; the upper part is thicker and has mounting screw holes with internal threads embedded in the top surface; the lower part is thinner and has mounting through holes.

[0012] The inner wall of the outer casing has a vertical positioning groove corresponding to the positioning protrusion of the assembly structure; the inner wall of the outer casing has a set of mounting screw holes of different heights corresponding to the horizontal installation position of the assembly structure.

[0013] This invention proposes a multi-band antenna for the Internet of Things (IoT). By designing a source antenna with an adjustable resonant cavity, it achieves effective antenna radiation across multiple frequency bands. Furthermore, this structure allows for easy adjustment of the operating frequency band during application.

[0014] Other features and advantages of this utility model will become clearer after reading the detailed description of the embodiments of this utility model in conjunction with the accompanying drawings. Attached Figure Description

[0015] To clearly illustrate the technical solution and embodiments of this utility model, the accompanying drawings are briefly described below. It should be noted that the drawings are primarily intended to explain the interconnections, structural features, and advantages of the various components of the device, and are not drawn to scale according to the actual dimensions of the device. Obviously, the drawings only relate to a limited set of embodiments and should not be construed as limiting the present utility model. Those skilled in the art can easily obtain new embodiments through formal variations based on these drawings.

[0016] Figure 1 This is a schematic diagram of the structure of one embodiment of the present utility model;

[0017] Figure 2 This is a schematic diagram of the structure of the source antenna in one embodiment of the present invention;

[0018] Figure 3 This is a graph showing the reflection coefficient as a function of frequency according to one embodiment of the present invention;

[0019] Figure 4 This is a schematic diagram of an assembly structure according to an embodiment of the present invention. Detailed Implementation

[0020] The specific embodiments of this utility model are described in detail below with reference to the accompanying drawings.

[0021] This invention proposes a multi-band antenna for the Internet of Things (IoT), comprising a source antenna and a resonant cavity structure assembled within a cylindrical housing. The source antenna includes a circular dielectric substrate, a feed source located on the lower surface of the substrate, and a coupling radiation element on the upper surface. The feed source and coupling radiation element are thin metal layers with specific geometric shapes fabricated on the substrate using a printing process. The resonant cavity structure comprises three layers from top to bottom: a first dielectric layer, a second dielectric layer, and a reflective layer, with air layers separating each layer at a specific distance. The first dielectric layer is a circular low-loss dielectric substrate with a thickness of D1; the second dielectric layer is a circular low-loss dielectric substrate with a thickness of D2; and the reflective layer is a circular PCB board with its entire upper surface covered in copper. The source antenna is located between the second dielectric layer and the reflective layer. Figure 1 A longitudinal sectional view of one embodiment of the present invention is provided. As shown in the figure, a reflective layer A1, a source antenna A2, a second dielectric layer A3, and a first dielectric layer A4 are sequentially assembled from bottom to top inside the outer casing. Each layer is fixed at a predetermined height position by four assembly structural members A5 located on the inner sidewall of the outer casing, and the four assembly structural members are evenly distributed along the circumference. The source antenna has a coupling radiation unit A6 on its upper surface and a feed source A7 on its lower surface, which is fed through a coaxial connector A8. An external antenna connector A9 is assembled at the bottom of the outer casing and connected to the coaxial connector A8 through an RF cable. A through hole is provided on the reflective layer at the position corresponding to the external antenna connector A9 for the RF cable to pass through. The top of the outer casing is open, and the upper surface of the first dielectric layer is flush with the upper edge of the outer casing, with the joint between the two filled with waterproof sealant.

[0022] The parameters of the aforementioned antenna structure, such as the dielectric substrate thickness, dielectric constant, spacing between layers, size of the feed dipole, and shape and size of the coupled radiating element, are determined using the CST simulation tool based on electromagnetic field theory. In a simulation-designed multi-band antenna embodiment, the feed A7 on the lower surface of the source antenna employs a dipole structure, and the coupled radiating element A6 on the upper surface of the source antenna uses a structure of four hexagonal split rings arranged in a honeycomb pattern. Figure 2As shown in the figure, B1 is the dielectric substrate, B2 is the hexagonal split ring structure, and there are four mounting holes B3 on the edge of the circular substrate. The measured reflection coefficient of this embodiment varies with frequency as follows: Figure 3 As shown in the figure, this embodiment achieves effective radiation in the three frequency bands of f = 1.57, 3.5, and 6.48a.

[0023] The multi-band antenna proposed in this invention is based on the following principle: two dielectric substrates with specific dielectric constants and thicknesses, together with a reflective layer, form an electromagnetic field "trap" around the source antenna, causing electromagnetic waves to reflect multiple times and interfere with each other. The metal reflective layer located below the source antenna also prevents energy leakage downwards and eliminates reverse radiation, thereby concentrating electromagnetic energy in the antenna's radiation direction. This structure enhances the antenna gain in the following ways: due to the presence of the resonant cavity, the antenna's radiation directivity is significantly enhanced. After multiple reflections within the resonant cavity, electromagnetic waves are mainly radiated from the opening direction of the resonant cavity, forming a unidirectional radiation mode. This enhanced directivity significantly improves the antenna's gain. The electromagnetic field within the resonant cavity is concentrated in a smaller space, allowing the antenna to radiate energy more effectively at its operating frequency. This concentration effect further improves the antenna's radiation efficiency and gain. The electromagnetic coupling between the source antenna and the resonant cavity structure affects the resonant frequency position and characteristics of the source antenna itself and introduces additional resonant frequencies. Therefore, by adjusting the parameters of the resonant cavity structure, including the dielectric substrate thickness, dielectric constant, and spacing between layers, multiple resonant frequencies can be adjusted.

[0024] Based on the above principles, this utility model designs an assembly structure with an adjustable height position on-site. Figure 4 The side view and longitudinal section diagram are provided. The top surface of the assembly structure A5 supports the upper assembly components, including the first dielectric layer, the second dielectric layer, the source antenna, and the reflector layer components. It has an internally threaded assembly screw hole C1. Its arc-shaped back can be installed close to the outer shell. It has positioning protrusions C5 at both ends, and there are 4 pairs of 8 vertical positioning grooves on the inner wall of the outer shell to define the position of the assembly structure in the horizontal plane. Its lower part is thinner and has a mounting through hole C2. There is a set of screw holes C3 at different heights on the inner wall of the outer shell corresponding to the installation position. During assembly, screws C4 are passed through the mounting through hole C2 and screwed into the screw holes C3 to fix the assembly structure A5.

[0025] When applying this utility model, during assembly, the relative positions of the first dielectric layer, the second dielectric layer, the source antenna, and the reflector layer in height can be adjusted by adjusting the installation positions of the four assembly structural components A5 on the side wall. At the same time, dielectric plates of different thicknesses and dielectric constants can be replaced to form different resonance effects, ultimately achieving the purpose of adjusting the resonance frequency and characteristics.

[0026] The description of this utility model is given for illustrative purposes only and is not intended to be exhaustive or to limit the utility model to the disclosed forms. The embodiments were chosen and described to better illustrate the principles and practical applications of the utility model, and to enable those skilled in the art to understand the utility model and design various embodiments with various modifications suitable for a particular purpose. All new embodiments that fall within the basic concept, construction principles, and spirit of this utility model, and are achieved through simple variations, modifications, equivalent substitutions, or improvements, should be included within the scope of protection of this utility model. The scope of this utility model is defined by the appended claims.

Claims

1. An Internet of Things multi-band antenna, characterized by, The multi-band antenna of the Internet of Things comprises a cylindrical shell, a vibration source antenna and a resonant cavity structure assembled in the shell; wherein the vibration source antenna comprises a circular dielectric substrate, a feed source on the lower surface of the substrate and a coupling radiation unit on the upper surface; the resonant cavity structure comprises three layers from top to bottom: a first dielectric layer, a second dielectric layer and a reflection layer, and the layers are separated by air layers at specific distances; the vibration source antenna is located between the second dielectric layer and the reflection layer.

2. The IoT multiband antenna of claim 1, wherein, The first dielectric layer and the second dielectric layer are circular low-loss dielectric plates; and the reflection layer is a circular PCB plate with copper on the upper surface.

3. The IoT multiband antenna of claim 1, wherein, The feed source and the coupling radiation unit are thin metal layers with specific geometric shapes processed on the substrate by printing process.

4. The IoT multiband antenna of claim 3, wherein, The feed source is an electric dipole structure, and the coupling radiation unit is a 6-hexagon split ring structure arranged in a honeycomb shape.

5. The IoT multiband antenna of claim 1, wherein, The feed source is fed by a coaxial connector; an external antenna connector is assembled at the bottom of the shell, and a radio frequency cable is connected to the coaxial connector; the reflection layer has a through hole at the position corresponding to the external antenna connector for passing through the radio frequency cable.

6. The IoT multiband antenna of claim 1, wherein, The top of the shell is open, the upper surface of the first dielectric layer is flush with the upper edge of the shell, and the joint part is filled with waterproof sealant.

7. The IoT multiband antenna of claim 1, wherein, The first dielectric layer, the second dielectric layer, the vibration source antenna and the reflection layer are respectively fixed at different height positions in the shell by four assembly structure members; the four assembly structure members of each layer are located on the same horizontal plane and are uniformly distributed along the circumference of the inner wall of the shell.

8. The IoT multiband antenna of claim 7, wherein, The back of the assembly structure member is arc-shaped, and the two ends are provided with positioning protruding structures; the upper part is thicker, and the top surface is embedded with a mounting screw hole with internal threads; the lower part is thinner, and has a mounting through hole.

9. The Internet of Things multiband antenna according to any one of claims 7 or 8, characterized in that, The inner wall of the shell has vertical positioning grooves corresponding to the positioning protruding structures of the assembly structure members; and the inner wall of the shell has a group of mounting screw holes with different heights corresponding to the horizontal mounting positions of the assembly structure members.

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