Low-cost ultra-wideband microstrip patch antenna

Abstract

The invention provides a low-cost ultra-wideband microstrip patch antenna, which comprises an upper metal layer, a middle dielectric layer and a lower metal layer, and is characterized in that an antenna part arranged on the upper metal layer comprises a rectangular patch and an inverted U-shaped patch, the inverted U-shaped patch surrounds the rectangular patch and is symmetrically arranged by taking a central axis of the rectangular patch as a symmetry axis, and the middle dielectric layer is arranged on the lower metal layer; and feeding is realized through coupling between the two. The invention aims to solve the problem of system performance reduction caused by factors such as material parameters and process errors, and does not need to increase the number of layers and the thickness of the antenna lamination, thereby achieving excellent performance while maintaining cost friendliness. On the basis that the thickness of the PCB is not increased, an existing patch antenna is ingeniously cut, the bandwidth of the antenna is successfully expanded, and an effective and economical solution is provided for innovation of antenna design.

Description

Technical Field

[0001] The present invention relates to the technical field of millimeter wave radar antennas, and in particular to a low-cost ultra-wideband microstrip patch antenna. Background Art

[0002] Antenna is a device that converts guided electromagnetic waves into radiated electromagnetic waves (or converts radiated electromagnetic waves into guided electromagnetic waves), and plays an important role in wireless communications. Today, as millimeter wave technology has made significant progress, achieving a low-cost and high-performance antenna has become an unavoidable issue in every millimeter wave system.

[0003] Since the wavelength of electromagnetic waves in the millimeter wave band is only a few millimeters, it is very sensitive to size, which puts higher requirements on PCB board materials and etching processes, which means higher processing costs. By designing antennas with wider bandwidths, it is more effective to resist the error of board parameter deviation and processing size, which becomes a problem that antennas need to solve.

[0004] Microstrip patch antennas have become the most commonly used antenna form in millimeter wave systems due to their low cost, easy processing, and high integration, but they also have the natural defect of narrow bandwidth. To solve this problem, researchers have explored a variety of methods, including using multi-layer microstrip patch antennas, which can extend the bandwidth but also increase the complexity and cost of the system. Another method is to use a thicker substrate, but this may cause radiation problems in the feed line and increase the thickness of the product. Summary of the invention

[0005] In view of the shortcomings of the prior art mentioned above, the purpose of the present invention is to provide a low-cost ultra-wideband microstrip patch antenna, which is used to solve the technical problems in the prior art that due to the limited antenna bandwidth, the thickened PCB board stacking and the use of a multi-layer structure microstrip patch antenna are used, which leads to increased product thickness, significant feeder radiation problems, and increased complexity and cost.

[0006] To achieve the above-mentioned purpose and other related purposes, the present invention provides a low-cost ultra-wideband microstrip patch antenna, comprising: an upper metal layer, an intermediate dielectric layer and a lower metal layer; the upper metal layer, the intermediate dielectric layer and the lower metal layer are tightly fitted; wherein an antenna part, a transmission line part and a metal ground part are arranged on the upper metal layer; the antenna part is connected to the transmission line part, and the antenna part is surrounded by a metal ground part; the metal ground part is connected to the lower metal layer; the antenna part comprises: a rectangular patch and an inverted U-shaped patch; the inverted U-shaped patch surrounds the rectangular patch and is symmetrical with a central axis of the rectangular patch as a symmetry axis; the inverted U-shaped patch is coupled with the rectangular patch to achieve feeding.

[0007] In one embodiment of the present invention, the inverted U-shaped patch is composed of two side arms of the same size and a top, forming a ring structure with an open bottom; wherein the two side arms are two vertical branches of the inverted U-shaped patch; the top is the horizontal part of the inverted U-shaped patch, and its two ends are respectively connected to the upper ends of the two side arms; the two side arms are symmetrical with the central axis extending vertically from the center of the top as the axis of symmetry.

[0008] In one embodiment of the present invention, the two side arms of the inverted U-shaped patch are respectively parallel to the two side edges of the rectangular patch, and the top of the inverted U-shaped patch is parallel to the upper edge of the rectangular patch; the inverted U-shaped patch surrounds the two side edges and the upper end of the rectangular patch, so that the inverted U-shaped patch and the rectangular patch form an inverted U-shaped coupling gap.

[0009] In one embodiment of the present invention, the bottom ends of the two side arms of the inverted U-shaped patch and the bottom ends of the two side edges of the rectangular patch are on the same horizontal line.

[0010] In one embodiment of the present invention, the width of the rectangular patch is half the wavelength of the operating frequency to ensure that the currents on the rectangular patch are in phase.

[0011] In one embodiment of the present invention, the length of the rectangular patch is set within a range of about 1.5 times the width.

[0012] In one embodiment of the present invention, the top length of the inverted U-shaped patch is the wavelength of the operating frequency.

[0013] In one embodiment of the present invention, the length of the side arm of the inverted U-shaped patch is set according to the impedance matching condition of the antenna part.

[0014] In one embodiment of the present invention, the lower end of the rectangular patch is connected to the transmission line portion to form a T-shaped structure therewith.

[0015] In one embodiment of the present invention, the metal ground portion is connected to the lower metal layer through a metallized via.

[0016] As described above, the present invention is a low-cost ultra-wideband microstrip patch antenna having the following beneficial effects: The present invention provides a low-cost ultra-wideband microstrip patch antenna, comprising: an upper metal layer, an intermediate dielectric layer and a lower metal layer, wherein the antenna portion disposed on the upper metal layer comprises a rectangular patch and an inverted U-shaped patch, wherein the inverted U-shaped patch surrounds the rectangular patch and is symmetrically arranged with a central axis of the rectangular patch as a symmetry axis, and feeding is achieved through coupling between the two. The present invention aims to solve the problem of system performance degradation caused by factors such as material parameters and process errors, without increasing the number of layers and thickness of the antenna stack, thereby achieving excellent performance while maintaining cost-friendliness. By cleverly cutting the existing patch antenna without increasing the thickness of the PCB board, the antenna bandwidth is successfully expanded, providing an effective and economical solution for innovation in antenna design. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Shown is a schematic exploded view of the structure of a low-cost ultra-wideband microstrip patch antenna in one embodiment of the present invention.

[0018] Figure 2 Shown is a schematic structural diagram of a low-cost ultra-wideband microstrip patch antenna in an embodiment of the present invention.

[0019] Figure 3 FIG. 1 is a schematic diagram showing the current flow of a low-cost ultra-wideband microstrip patch antenna according to an embodiment of the present invention. DETAILED DESCRIPTION

[0020] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0021] It should be noted that in the following description, reference is made to the accompanying drawings, which describe several embodiments of the present invention. It should be understood that other embodiments may also be used, and that mechanical composition, structural, electrical and operational changes may be made without departing from the spirit and scope of the present invention. The following detailed description should not be considered restrictive, and the scope of the embodiments of the present invention is limited only by the claims of the published patents. The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. Spatially related terms, such as "upper", "lower", "left", "right", "below", "below", "lower", "above", "upper", etc., may be used in the text to facilitate the description of the relationship between an element or feature shown in the figure and another element or feature.

[0022] Throughout the specification, when a part is said to be "connected" to another part, this includes not only the case of "direct connection" but also the case of "indirect connection" by placing other elements therebetween. In addition, when a part is said to "include" a certain constituent element, unless otherwise stated, it does not exclude other constituent elements, but means that other constituent elements may be included.

[0023] The terms first, second and third mentioned herein are used to describe various parts, components, regions, layers and / or segments, but are not limited thereto. These terms are only used to distinguish a certain part, component, region, layer or segment from other parts, components, regions, layers or segments. Therefore, the first part, component, region, layer or segment described below may refer to the second part, component, region, layer or segment within the scope of the present invention.

[0024] Furthermore, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless there is an indication to the contrary in the context. It should be further understood that the terms "comprise", "include" indicate the presence of the described features, operations, elements, components, items, kinds, and / or groups, but do not exclude the presence, occurrence or addition of one or more other features, operations, elements, components, items, kinds, and / or groups. The terms "or" and "and / or" used herein are interpreted as inclusive, or mean any one or any combination. Therefore, "A, B or C" or "A, B and / or C" means "any of the following: A; B; C; A and B; A and C; B and C; A, B and C". Exceptions to this definition will only occur when the combination of elements, functions or operations is inherently mutually exclusive in some way.

[0025] The present invention provides a low-cost ultra-wideband microstrip patch antenna, comprising: an upper metal layer, an intermediate dielectric layer and a lower metal layer, wherein the antenna portion arranged on the upper metal layer comprises a rectangular patch and an inverted U-shaped patch, wherein the inverted U-shaped patch surrounds the rectangular patch and is symmetrically arranged with a central axis of the rectangular patch as a symmetry axis, and feeding is achieved through coupling between the two. The present invention aims to solve the problem of system performance degradation caused by factors such as material parameters and process errors, without increasing the number of layers and thickness of the antenna stack, thereby achieving excellent performance while maintaining cost friendliness. By cleverly cutting the existing patch antenna without increasing the thickness of the PCB board, the antenna bandwidth is successfully expanded, providing an effective and economical solution for innovation in antenna design.

[0026] The following is a detailed description of the embodiments of the present invention with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. The present invention can be embodied in many different forms and is not limited to the embodiments described herein.

[0027] like Figure 1 A schematic exploded view of the structure of a low-cost ultra-wideband microstrip patch antenna in an embodiment of the present invention is shown.

[0028] Applied to millimeter wave radar antenna, the antenna includes two metal layers: an upper metal layer 1 and a lower metal layer 2; the upper metal layer 1 is located at the top of the antenna and is the main radiation part of the antenna; the upper metal layer 1 is etched to realize the metal pattern shown in the figure, and the metal pattern is the antenna with radiation characteristics; the middle dielectric layer is located between the upper metal layer 1 and the lower metal layer 2, and plays a supporting and isolating role, and a PCB dielectric is usually used; the upper metal layer 1, the middle dielectric layer and the lower metal layer 2 are tightly attached; the lower metal layer 2 is located at the bottom of the antenna and is usually used as the grounding layer of the antenna.

[0029] The upper metal layer 1 is the main component of the antenna, on which the antenna part, the transmission line part and the connection with the metal ground part are arranged. These parts work together to ensure that the antenna can efficiently receive and transmit electromagnetic waves.

[0030] like Figure 2 , the antenna part includes: a rectangular patch 101 and an inverted U-shaped patch 102;

[0031] The rectangular patch 101 has a rectangular structure, with two parallel sides and upper and lower sides perpendicular to the two sides; the length of the side is the width of the rectangular patch, and the length of the upper side is the length of the rectangular patch. The rectangular patch 101 is usually made of a metal material with good conductive properties, such as copper, aluminum or alloy. The rectangular patch 101 is the main radiation part of the antenna and can generate a stable radiation far field.

[0032] The inverted U-shaped patch 102 is shaped like an inverted English letter "U". Specifically, it is composed of two vertical side arms and a horizontal top arm, and the two vertical arms are connected at the bottom to form an inverted "U" structure with an opening downward. The inverted U-shaped patch is usually made of a metal material with good conductive properties, such as copper, aluminum or alloy.

[0033] The inverted U-shaped patch 102 surrounds the rectangular patch 101 and is symmetrical with a central axis of the rectangular patch 101 as the axis of symmetry; the inverted U-shaped patch is coupled with the rectangular patch to achieve feeding. The two vertical arms of the inverted U-shaped patch 102 are distributed at equal distances on both sides of the rectangular patch and are symmetrical with respect to the central axis. This symmetry helps to ensure that the radiation characteristics of the antenna are uniform in all directions. A coupling slot is formed between the inverted U-shaped patch 102 and the rectangular patch 101, and feeding is achieved through the coupling slot. The size of the slot should be as small as possible (satisfying the processing conditions) to ensure that sufficient energy is coupled. This means that electromagnetic waves are not transmitted directly from the feed line to the rectangular patch through a physical connection, but are transmitted through the electromagnetic field interaction between the inverted U-shaped patch 102 and the rectangular patch 101. When the antenna is working, the rectangular patch 101 and the inverted U-shaped patch 102 can achieve radiation in different working modes. Thereby achieving the expansion of the antenna bandwidth and the stability of radiation. Due to the presence of the inverted U-shaped patch 102, the antenna can radiate at other frequencies, thereby achieving the expansion of impedance bandwidth.

[0034] The transmission line section is used to transmit electromagnetic waves from one part of the antenna to another, or from the antenna to an external circuit.

[0035] The metal ground part is a large conductive layer located around the antenna part and connected to the lower metal layer 2, which together provide a reflective structure for the antenna to make its directionality controllable. At the same time, the upper metal ground 1 can limit the surface wave of the antenna to a fixed area to enhance its radiation and reduce interference with other devices. Here, the metal between the upper metal layer 1 and the lower metal layer 2 forms a metal cavity, and the metal cavity can be resonated at the desired operating frequency by adjusting the size of the metal cavity.

[0036] In one embodiment, the metal ground portion is connected to the lower metal layer 2 through a metallized via.

[0037] In one embodiment, if Figure 2 As shown, the inverted U-shaped patch 102 consists of two side arms of the same size and a top, forming a ring structure with an open bottom. This structure enables the inverted U-shaped patch 102 to be coupled and fed with the rectangular patch 101, thereby achieving efficient electromagnetic wave transmission and radiation.

[0038] Among them, the two side arms are two vertical branches of the inverted U-shaped patch 102; the top is the horizontal part of the inverted U-shaped patch 102, and its two ends are connected to the upper ends of the two side arms respectively; the two side arms are symmetrical with the central axis extending vertically from the center of the top as the symmetry axis, which means that the two side arms are symmetrical about this central axis in shape, size and position. This symmetry helps to ensure that the radiation characteristics of the antenna are uniform in all directions, thereby improving the overall performance of the antenna. At the same time, symmetry also helps to simplify the manufacturing and assembly process of the antenna.

[0039] In one embodiment, the two side arms of the inverted U-shaped patch 102 are respectively parallel to the two side edges of the rectangular patch 101, and the top of the inverted U-shaped patch 102 is parallel to the upper edge of the rectangular patch 101; the inverted U-shaped patch 102 surrounds the two side edges and the upper end of the rectangular patch 101, so that the inverted U-shaped patch 102 and the rectangular patch 101 form an inverted U-shaped 102 coupling seam.

[0040] In a specific embodiment, the bottom ends of the two side arms of the inverted U-shaped patch 102 and the bottom ends of the two side edges of the rectangular patch 101 are on the same horizontal line.

[0041] In one embodiment, the width of the rectangular patch 101, that is, the length of the two side arms, is half the wavelength of the operating frequency. At this length, the current on the rectangular patch 101 can remain in phase, thereby superimposing in the far field to achieve radiation; the "in phase" here means that the current has the same direction in each part, so that the electromagnetic waves they generate will reinforce each other to form effective radiation.

[0042] In one embodiment, the length of the rectangular patch 101 is flexibly set to a range of about 1.5 times the width. This ratio is not strictly limited to 1.5 times, but is allowed to be adjusted within a relatively close value, such as between 1.4 times and 1.6 times, to meet different application requirements. 1.5 times, as a practically verified empirical value, plays a key role in the impedance matching of the antenna. By setting the length within this ratio range, the energy transmission efficiency between the antenna and the transmission line can be significantly improved, thereby optimizing the overall performance of the antenna.

[0043] In one embodiment, the top length of the inverted U-shaped patch 102 is the wavelength of the operating frequency.

[0044] In one embodiment, the length of the side arms of the inverted U-shaped patch 102 is set according to the impedance matching of the antenna part.

[0045] In one embodiment, the transmission line portion includes not only the transmission line itself, but also an impedance transformation structure. The transmission line is a microstrip line. Microstrip lines have the advantages of simple structure, easy integration, and low cost, and are therefore widely used in various microwave and millimeter wave circuits. The main function of the impedance transformation structure is to match the impedance between the antenna and the transmission line to ensure that the electromagnetic wave signal can be efficiently transmitted. The impedance transformation structure can be implemented in a variety of ways, such as using a quarter-wavelength transformer, a gradient line, a stepped impedance transformer, and the like. These structures can be selected and optimized according to specific application requirements and antenna design parameters. The transmission line portion ensures a good match between the antenna and the transmission line through a reasonable impedance transformation structure, thereby improving the overall performance of the antenna.

[0046] In one embodiment, if Figure 2 The lower end of the rectangular patch 101 is connected to the transmission line part to form a T-shaped structure therewith.

[0047] In one embodiment, the substrate structure is composed of an upper metal layer, an intermediate dielectric layer and a lower metal layer. The substrate thickness may be 10 mils. When a thicker substrate is used, a wider bandwidth may be achieved. In the millimeter wave frequency band, attention should also be paid to the problem of transmission line radiation.

[0048] In a specific embodiment, the mechanism of achieving bandwidth expansion of the low-cost ultra-wideband microstrip patch antenna of the present invention is a complex and sophisticated design process, which involves multiple aspects such as the antenna's radiation pattern, surface current distribution, impedance matching, and size adjustment. The following is a detailed explanation of this mechanism:

[0049] When the antenna is working, current distribution will be generated on its surface. These currents are superimposed in phase in space to form a specific radiation pattern. Different working modes correspond to different current distributions and radiation patterns. By adjusting the working mode of the antenna, its radiation characteristics can be changed to achieve coverage of the working frequency. For example, Figure 3 , the solid line represents the current when one mode is working, while the dotted line represents the current when the other mode is working. These two modes may have different operating frequencies and radiation characteristics. By cleverly switching or combining these two modes, the working bandwidth of the antenna can be extended.

[0050] The impedance characteristics of an antenna are the key to its energy transmission efficiency. In order to achieve good impedance matching, the size, shape and material of the antenna need to be adjusted so that its input impedance matches the characteristic impedance of the transmission line. In antenna design, the impedance bandwidth of the antenna can be optimized through appropriate size adjustment. Impedance bandwidth refers to the frequency range in which the antenna can work stably while maintaining a certain radiation efficiency and impedance matching. Through careful design and adjustment, the working bandwidth of the antenna can reach nearly 10% or even higher.

[0051] The present invention has the following beneficial effects:

[0052] 1. The present invention successfully expands the antenna bandwidth by ingeniously cutting the existing patch antenna without increasing the thickness of the PCB board. This design not only reduces the manufacturing cost of the antenna, but also improves the performance and bandwidth of the antenna.

[0053] 2. The coupling effect between the inverted U-shaped patch and the rectangular patch realizes feeding. This feeding method can reduce the length and complexity of the feeding line, thereby reducing the manufacturing cost and complexity of the antenna. At the same time, coupled feeding can also improve the bandwidth and performance stability of the antenna.

[0054] 4. The antenna design of the present invention does not need to increase the number of layers and thickness of the antenna stack, thereby achieving effective cost control while ensuring performance. This cost-friendly design makes the antenna have a wide range of application prospects in wireless communication systems.

[0055] In summary, the low-cost ultra-wideband microstrip patch antenna of the present invention comprises: an upper metal layer, an intermediate dielectric layer and a lower metal layer, wherein the antenna portion arranged on the upper metal layer comprises a rectangular patch and an inverted U-shaped patch, wherein the inverted U-shaped patch surrounds the rectangular patch and is symmetrically arranged with a central axis of the rectangular patch as a symmetry axis, and feeding is achieved through coupling between the two. The present invention aims to solve the problem of system performance degradation caused by factors such as material parameters and process errors, without increasing the number of layers and thickness of the antenna stack, thereby achieving excellent performance while maintaining cost-friendliness. By cleverly cutting the existing patch antenna without increasing the thickness of the PCB board, the antenna bandwidth is successfully expanded, providing an effective and economical solution for the innovation of antenna design. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has a high industrial utilization value.

[0056] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A low-cost ultra-wideband microstrip patch antenna, characterized in that: include: An upper metal layer, an intermediate dielectric layer and a lower metal layer; the upper metal layer, the intermediate dielectric layer and the lower metal layer are tightly attached; The upper metal layer is provided with an antenna part, a transmission line part and a metal ground part; the antenna part is connected to the transmission line part, and the antenna part is surrounded by a metal ground part; the metal ground part is connected to the lower metal layer; The antenna part includes: a rectangular patch and an inverted U-shaped patch; the inverted U-shaped patch surrounds the rectangular patch and is symmetrical with a central axis of the rectangular patch as a symmetry axis; the inverted U-shaped patch is coupled with the rectangular patch to realize feeding.

2. The low-cost ultra-wideband microstrip patch antenna according to claim 1, characterized in that: The inverted U-shaped patch consists of two side arms of the same size and a top, forming a ring structure with an open bottom; wherein the two side arms are two vertical branches of the inverted U-shaped patch; the top is the horizontal part of the inverted U-shaped patch, and its two ends are respectively connected to the upper ends of the two side arms; the two side arms are symmetrical with the central axis extending vertically from the center of the top as the symmetry axis.

3. The low-cost ultra-wideband microstrip patch antenna according to claim 2, characterized in that: The two side arms of the inverted U-shaped patch are respectively parallel to the two side edges of the rectangular patch, and the top of the inverted U-shaped patch is parallel to the upper edge of the rectangular patch; the inverted U-shaped patch surrounds the two side edges and the upper end of the rectangular patch, so that the inverted U-shaped patch and the rectangular patch form an inverted U-shaped coupling gap.

4. The low-cost ultra-wideband microstrip patch antenna according to claim 3, characterized in that: The bottom ends of the two side arms of the inverted U-shaped patch and the bottom ends of the two side edges of the rectangular patch are on the same horizontal line.

5. The low-cost ultra-wideband microstrip patch antenna according to claim 3, characterized in that: The width of the rectangular patch is half the wavelength of the operating frequency to ensure that the current phases on the rectangular patch are consistent.

6. The low-cost ultra-wideband microstrip patch antenna according to claim 5, characterized in that: The length of the rectangular patch is set within a range of about 1.5 times the width.

7. The low-cost ultra-wideband microstrip patch antenna according to claim 2, characterized in that: The top length of the inverted U-shaped patch is the wavelength of the operating frequency.

8. The low-cost ultra-wideband microstrip patch antenna according to claim 2, characterized in that: The length of the side arm of the inverted U-shaped patch is set according to the impedance matching condition of the antenna part.

9. The low-cost ultra-wideband microstrip patch antenna according to claim 3, characterized in that: The lower end of the rectangular patch is connected to the transmission line part to form a T-shaped structure therewith.

10. The low-cost ultra-wideband microstrip patch antenna according to claim 1, characterized in that: The metal ground portion is connected to the lower metal layer through a metallized via.

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