An OBU microstrip antenna

Abstract

The utility model is suitable for antenna field provides a kind of OBU microstrip antenna, including the front microstrip antenna and feed line, first dielectric layer, ground layer, second dielectric layer and back microstrip antenna of fixed connection from top to bottom sequentially laminated in proper order;The ground layer central position is provided with long slit, the length direction of the long slit is perpendicular to the connection direction of feed line and antenna body in front microstrip antenna and feed line feed line, after being fed by front microstrip antenna and feed line, the electromagnetic coupling feed of back microstrip antenna is realized through the long slit of ground layer, so that the antenna body in front microstrip antenna and feed line and back microstrip antenna are synchronously radiated microwave signal to both sides;The utility model, without distinguishing installation front and back, adaptation car owner diversification installation demand, solve the problem of passing caused by improper installation direction of traditional directional antenna, and simple structure, FR4 substrate is easy to mass-produce, effectively improve ETC transaction stability and popularization convenience.

Description

Technical Field

[0001] This utility model belongs to the field of antennas, and in particular relates to an OBU microstrip antenna. Background Technology

[0002] Currently, almost all OBU antennas adopt a microstrip antenna structure, specifically falling into three categories: the first type integrates a microstrip antenna with parasitic elements on a circuit board, with the core design goal of enhancing directional radiation performance; the second type features a microstrip antenna without parasitic elements mounted on a circuit board; and the third type separates the antenna radiating element from the circuit board, achieving antenna feeding through an electrical coupling slot created in the circuit board's ground plane. All of these OBU antenna designs are primarily for directional radiation, without specifically considering the need to simultaneously radiate microwave signals to both the front and back. Because existing OBU microstrip antennas are all directional radiation designs, they only have high gain and strong signal in the forward radiation direction, but low gain and weak signal in the backward radiation direction, which leads to many pain points in practical use: Due to diverse usage habits, some private car owners will install the OBU with the back facing outwards (such as by attaching it to the center console). In this case, when the OBU interacts with the ETC roadside unit (RSU), problems may arise such as obstructed passage in and out of highway lanes and difficulty in effectively marking vehicle information by the gantry antenna. Meanwhile, the directional radiation design requires car owners to carefully distinguish the front and back of the OBU during installation, which is cumbersome and increases the barrier to entry for users. Therefore, an OBU microstrip antenna is needed to solve the above problems. Utility Model Content

[0003] The purpose of this utility model embodiment is to provide an OBU microstrip antenna to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, this utility model provides the following technical solution: An OBU microstrip antenna includes a front microstrip antenna and feed line, a first dielectric layer, a ground layer, a second dielectric layer and a back microstrip antenna, which are fixedly connected from top to bottom. The front microstrip antenna and feed line are metal layers. One end of the feed line is connected to an external power supply unit, and the other end is integrally formed with the front microstrip antenna body. The ground layer is a metal layer with a long slot in its middle. The long slot is located at the center of the orthographic projection of the front microstrip antenna body, and the length direction of the long slot is perpendicular to the connection direction between the feed line and the front microstrip antenna body. Both the first dielectric layer and the second dielectric layer are non-metallic insulating layers, which are respectively sandwiched between the front microstrip antenna and feed line and the ground layer, and between the ground layer and the back microstrip antenna, to achieve insulation isolation and structural support for each metal layer.

[0005] In a further technical solution, both the first dielectric layer and the second dielectric layer are made of FR4 substrate.

[0006] In a further technical solution, the shape and size of the front microstrip antenna body are completely identical to those of the back microstrip antenna.

[0007] In a further technical solution, the front microstrip antenna is fed by microstrip line feeding, and the rear microstrip antenna is fed by electromagnetic coupling feeding through a long slot in the ground.

[0008] In a further technical solution, both the front microstrip antenna body and the back microstrip antenna are circular metal sheet structures.

[0009] In a further technical solution, the front microstrip antenna and feed line, ground layer, and back microstrip antenna are all made of metal, while the first dielectric layer and the second dielectric layer are non-metallic layers, together forming an integrated stacked structure.

[0010] Compared with the prior art, the beneficial effects of this utility model are: This utility model adds a back microstrip antenna of the same specifications to the back of a traditional microstrip antenna and opens a long strip slit in the center of the metal ground layer. It uses electromagnetic coupling feeding to enable the front microstrip antenna and the antenna body in the feed line to radiate microwave signals to both sides synchronously with the back microstrip antenna. The bidirectional radiation gain remains efficient and stable, which completely solves the problems of poor passage and difficulty in marking gantry antennas when the vehicle owner installs the OBU with the back facing the vehicle, and ensures the smooth completion of the transaction. This utility model features a bidirectional radial structure design, which eliminates the need to distinguish the installation direction of the OBU. Car owners can freely install it according to their own usage habits (such as attaching it to the windshield or center console) without having to judge the front or back. This simplifies the installation process, lowers the user threshold, increases car owners' acceptance of the OBU, and facilitates the widespread promotion of the OBU. This utility model adopts an integrated stacked structure of a front microstrip antenna and feed line, a first dielectric layer, a ground layer, a second dielectric layer, and a back microstrip antenna. It has no complex parasitic units or separate components. Moreover, both the first and second dielectric layers use conventional FR4 substrate, which can be processed and formed by mature PCB technology. The structure is simple, easy to mass-produce and switch to mass production, effectively control production costs, and improve the efficiency of product marketing.

[0011] To more clearly illustrate the structural features and effects of this utility model, the following detailed description of this utility model is provided in conjunction with the accompanying drawings and specific embodiments. Attached Figure Description

[0012] Figure 1 This is a three-dimensional structural diagram of the present invention from the front view; Figure 2 This is a three-dimensional structural diagram of the present invention viewed from below; Figure 3 This is a frontal exploded three-dimensional structural diagram of the present invention.

[0013] In the figure: 1. Front microstrip antenna and feed line; 2. First dielectric layer; 3. Ground layer; 31. Long strip slot; 4. Second dielectric layer; 5. Back microstrip antenna. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0015] The specific implementation of this utility model will be described in detail below with reference to specific embodiments.

[0016] like Figure 1-3 As shown, this utility model embodiment provides an OBU microstrip antenna, including a front microstrip antenna and feed line 1, a first dielectric layer 2, a ground layer 3, a second dielectric layer 4 and a back microstrip antenna 5, which are fixedly connected from top to bottom. The front microstrip antenna and feed line 1 are metal layers. One end of the feed line is connected to the external power supply unit, and the other end is integrally formed with the front microstrip antenna body. The ground layer 3 is a metal layer with a long strip slit 31 in the middle. The long strip slit 31 is located in the center of the orthographic projection of the front microstrip antenna body, and the length direction of the long strip slit 31 is perpendicular to the connection direction between the feed line and the front microstrip antenna body. The first dielectric layer 2 and the second dielectric layer 4 are both non-metallic insulating layers, respectively sandwiched between the front microstrip antenna and feed line 1 and the ground layer 3, and between the ground layer 3 and the back microstrip antenna 5, to achieve insulation isolation and structural support for each metal layer.

[0017] In this embodiment, the front microstrip antenna and feed line 1 serve as the signal transmission core and power input terminal. The metal material ensures smooth signal transmission, and the integrated design of the feed line and antenna body avoids signal loss caused by additional connections. The first dielectric layer 2 is sandwiched between the front microstrip antenna and feed line 1 and the ground layer 3, serving as insulation and preventing short circuits between metal layers, while also providing stable support for the upper structure. The ground layer 3, as the intermediate key layer, uses metal material to ensure grounding stability. The elongated slot 31 in its central position is the core structure for bidirectional power feeding, conducting the electrical energy of the front antenna to the back side through electromagnetic coupling. The position and direction design of the elongated slot 31 ensures the uniformity of power feeding and guarantees the radiation effect of the back antenna. The second dielectric layer 4 is located between the ground layer 3 and the back microstrip antenna 5, and has the same function as the first dielectric layer 2, achieving insulation and structural support between the ground layer 3 and the back microstrip antenna 5. The back microstrip antenna 5 works in conjunction with the front microstrip antenna body to form a bidirectional radiation structure, fundamentally breaking the unidirectional radiation limitation of traditional directional antennas.

[0018] Specifically, both the first dielectric layer 2 and the second dielectric layer 4 are made of FR4 substrate.

[0019] In this embodiment, the FR4 substrate has excellent insulation properties, which can effectively isolate electromagnetic interference between the front microstrip antenna and feed line 1, ground layer 3, and back microstrip antenna 5, ensuring the purity of the radiated signal. At the same time, the FR4 substrate has good mechanical strength and environmental adaptability, which can cope with the use environment inside the vehicle and prevent the antenna structure from deforming or being damaged due to vibration, temperature changes, etc. In addition, the FR4 substrate is a commonly used material for conventional PCB boards, and the processing technology is mature and can be adapted to existing production processes, reducing production difficulty.

[0020] Specifically, the shape and size of the front microstrip antenna body and the rear microstrip antenna 5 are completely identical.

[0021] In this embodiment, the design ensures that the performance indicators of bidirectional radiation remain symmetrical, avoids uneven radiation signal strength in one direction due to structural differences, and ensures that the OBU can form a stable signal interaction with the RSU regardless of whether it is installed facing forward or backward, further improving the ease of use and reliability.

[0022] Specifically, the front microstrip antenna is fed by microstrip line feeding, while the rear microstrip antenna 5 is fed by electromagnetic coupling through the long strip slot 31 of the ground layer 3.

[0023] In this embodiment, the front microstrip antenna is fed by a microstrip line, which directly transmits power through the feed line, resulting in high feeding efficiency, low signal loss, and the ability to quickly convert external power into microwave radiation signals. The rear microstrip antenna 5 is fed by electromagnetic coupling through the long slot 31 of the ground layer 3, eliminating the need for an additional independent feed line, simplifying the overall structure. At the same time, this feeding method ensures the radiation coordination between the rear and front antennas, avoids signal interference, and guarantees the stability of bidirectional radiation.

[0024] Specifically, both the front microstrip antenna body and the rear microstrip antenna 5 are circular metal sheet structures.

[0025] Specifically, the front microstrip antenna and feed line 1, ground layer 3, and back microstrip antenna 5 are all made of metal, while the first dielectric layer 2 and the second dielectric layer 4 are non-metallic layers, together forming an integrated stacked structure.

[0026] In this embodiment, the front microstrip antenna and feed line 1, ground layer 3, and back microstrip antenna 5 are made of metal to ensure signal conduction and radiation performance; the first dielectric layer 2 and the second dielectric layer 4 are non-metallic layers to achieve insulation and support functions. The five-layer integrated stacked design has no complex separate parts, is compact, easy to process and assemble, and at the same time improves the overall structural stability and durability of the antenna.

[0027] This invention, through the synergistic effect of a five-layer integrated stacked structure, bidirectional symmetrical antenna design, and coupled feeding method, completely breaks the unidirectional radiation limitation of traditional OBU antennas, achieving efficient bidirectional radiation. It not only solves the problem of installation direction restriction, but also simplifies structural design and adapts to existing production processes. Overall, it achieves the comprehensive effect of "adapting to diverse installation needs, improving transaction stability, and facilitating mass production and promotion," and comprehensively solves multiple pain points in traditional technologies.

[0028] Working principle and usage process of this utility model: Power-on startup phase: The external power supply unit is connected to the front microstrip antenna and the feed line 1 through the wire, and inputs electrical energy to the front microstrip antenna and the feed line 1. The electrical energy is quickly conducted to the front microstrip antenna body along the feed line. The metal front microstrip antenna body is converted into microwave radiation signal under the excitation of electrical energy and radiates towards the front side of the OBU. Electromagnetic coupling feeding stage: The ground layer 3 serves as a metal grounding layer. The long strip slit 31 in the middle is located in the center of the orthographic projection of the front microstrip antenna body, and the length direction of the long strip slit 31 is perpendicular to the connection direction between the feed line and the front microstrip antenna body. This structural design enables the electromagnetic field generated by the front microstrip antenna body to form a strong electromagnetic coupling effect through the long strip slit 31, and efficiently couples some of the electrical energy to the back microstrip antenna 5 above the second dielectric layer 4, thereby realizing the feeding of the back microstrip antenna 5. Two-way radiation phase: Under the excitation of coupled electrical energy, the rear microstrip antenna 5 generates a microwave radiation signal with the same performance as the front microstrip antenna body, and radiates towards the side of the OBU that is away from the center console; since the front microstrip antenna body and the rear microstrip antenna 5 have the same shape and size and the feeding method is matched, the signal strength and coverage of the two-way radiation are consistent and there is no obvious difference. Transaction interaction phase: When a vehicle passes through the ETC lane, regardless of whether the OBU is installed facing forward or backward, one side of the bidirectional radiated microwave signal can always form an effective communication link with the roadside RSU. After receiving the signal radiated by the antenna, the RSU completes operations such as vehicle identification, ETC card information verification, and toll settlement. After settlement, the RSU sends a release signal, the barrier opens, and the vehicle passes through quickly. Throughout the process, the bidirectional radiation design of the antenna ensures a stable communication link, avoids signal interruption or attenuation due to installation direction issues, and guarantees traffic efficiency and transaction stability.

[0029] The circuits, electronic components, and modules involved are all existing technologies, which can be fully implemented by those skilled in the art, and need not be elaborated upon. The content protected by this utility model does not involve any improvement to the software and methods.

[0030] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An OBU microstrip antenna, characterized in that, It includes a front microstrip antenna and feed line (1), a first dielectric layer (2), a ground layer (3), a second dielectric layer (4), and a back microstrip antenna (5) that are fixedly connected from top to bottom. The front microstrip antenna and feed line (1) are metal layers. One end of the feed line is connected to the external power supply unit, and the other end is integrally formed with the front microstrip antenna body. The ground layer (3) is a metal layer, and a long strip slit (31) is provided in the middle of it. The long strip slit (31) is located in the center of the orthographic projection of the front microstrip antenna body, and the length direction of the long strip slit (31) is perpendicular to the connection direction between the feed line and the front microstrip antenna body. The first dielectric layer (2) and the second dielectric layer (4) are both non-metallic insulating layers, respectively sandwiched between the front microstrip antenna and feed line (1) and the ground layer (3), and between the ground layer (3) and the back microstrip antenna (5), to achieve insulation isolation and structural support for each metal layer.

2. The OBU microstrip antenna according to claim 1, characterized in that, The first dielectric layer (2) and the second dielectric layer (4) are both made of FR4 substrate.

3. The OBU microstrip antenna according to claim 1, characterized in that, The shape and size of the front microstrip antenna body and the back microstrip antenna (5) are completely identical.

4. An OBU microstrip antenna according to claim 1, characterized in that, The front microstrip antenna is fed by microstrip line feeding, and the back microstrip antenna (5) is fed by electromagnetic coupling feeding through the long strip opening (31) of the ground layer (3).

5. An OBU microstrip antenna according to claim 1, characterized in that, Both the front microstrip antenna body and the back microstrip antenna (5) are circular metal sheet structures.

6. An OBU microstrip antenna according to claim 1, characterized in that, The front microstrip antenna and feed line (1), ground layer (3), and back microstrip antenna (5) are all made of metal, while the first dielectric layer (2) and the second dielectric layer (4) are non-metallic layers, together forming an integrated stacked structure.

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