Antenna structure
By setting up an annular groove and a dielectric layer in the antenna structure, and using the combination of coplanar waveguide lines and dielectric layers, the problem of insufficient bandwidth of microstrip antennas is solved, and bandwidth expansion and signal efficiency improvement are achieved.
Patent Information
- Application Number
- CN202310797294.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-06-30
- Publication Date
- 2024-12-31
AI Technical Summary
The working bandwidth of existing microstrip antennas is narrow, making it difficult to meet the needs of modern wireless communication applications.
By providing a first conductive layer, a dielectric layer and a second conductive layer sequentially stacked in the thickness direction in the antenna structure, the current distribution is changed using the annular groove, the current path length is increased, resulting in a lower resonance point, and through the coplanar waveguide The line inputs the signal directly to reduce losses, while using a first dielectric layer with high Young's modulus and a second dielectric layer with low dielectric constant to reduce the Q value and expand the bandwidth.
The expansion of antenna bandwidth is achieved, signal loss is reduced, radiation efficiency is improved, and the overall weight of the antenna structure is reduced.
Smart Images
Figure CN119231171A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of circuit boards, and in particular to an antenna structure. Background Art
[0002] Microstrip antennas have the advantages of small size, light weight, low profile, and easy construction, and are widely used in communication and radar systems. With the rapid development of wireless communication technology, there are increasingly higher requirements for antennas used in wireless communication systems, but ordinary microstrip antennas have a relatively narrow working bandwidth and are difficult to meet the needs of today's wireless communication applications. Summary of the invention
[0003] In view of this, it is necessary to provide an antenna structure that is conducive to expanding bandwidth.
[0004] On the one hand, the present application provides an antenna structure, comprising a first conductive layer, a dielectric layer and a second conductive layer stacked in sequence along the thickness direction. The first conductive layer comprises at least one patch, each of which comprises a body, two spaced-apart feeding points and two spaced-apart annular grooves, each of which is arranged around one of the feeding points to separate the body from the feeding point. The antenna structure comprises two feeding holes corresponding to each of the patches, each of which passes through the dielectric layer, and each of which is electrically connected to a feeding point at one end and electrically connected to the second conductive layer at the other end.
[0005] The above-mentioned antenna structure of the present application changes the current distribution on the patch by setting the annular groove, increases the current path length, and makes the antenna produce a lower resonance point. The superposition of two adjacent resonance peaks increases the use bandwidth of the antenna structure, thereby achieving the purpose of expanding the bandwidth.
[0006] Based on the above aspects, in a possible implementation manner, the second conductive layer includes a coplanar waveguide line, and one end of each of the feeding holes is electrically connected to the coplanar waveguide line.
[0007] In the above possible methods, since the coplanar waveguide circuit itself has the advantages of low loss and small radiation interference, directly inputting the signal to the antenna patch through the feeding hole can reduce the use of balun and thus reduce the signal loss at the front end.
[0008] Based on the above aspects, in a possible implementation manner, each of the feeding points is located at the center of the annular groove arranged around the feeding point.
[0009] Based on the above aspects, in a possible implementation manner, the annular groove is in a circular ring shape, and the patch is in a rectangular shape.
[0010] Based on the above aspects, in a possible implementation, the dielectric layer includes two first dielectric layers stacked along the thickness direction and a second dielectric layer located between the two first dielectric layers. The Young's modulus of the first dielectric layer is greater than 5 GPa, and the dielectric constant is greater than 3.3. The dielectric constant of the second dielectric layer is less than 2.0, and the dielectric loss factor is less than 0.002.
[0011] In the above possible methods, the first dielectric layer is beneficial to improving the mechanical properties of the antenna structure, while the second dielectric layer has a lower dielectric constant and dielectric loss factor, which is beneficial to the radiation of electromagnetic waves, thereby reducing the Q value, and the bandwidth is inversely proportional to the Q value, that is, it is beneficial to increase the bandwidth.
[0012] Based on the above aspects, in a possible implementation manner, the porosity of each of the first medium layers is 0, and the porosity of the second medium layers is greater than 10%.
[0013] In the above possible manner, in the sandwich-type dielectric layer, the two first dielectric layers are provided to improve the stability of the pore structure in the second dielectric layer located in the middle. The pores in the second dielectric layer can introduce air, and air usually has a smaller dielectric constant. Therefore, the second dielectric layer with a large porosity is conducive to reducing the dielectric constant, thereby facilitating the expansion of the bandwidth, and at the same time, it is also conducive to reducing the overall weight of the antenna structure.
[0014] Based on the above aspects, in a possible implementation manner, the thickness of the dielectric layer is less than or equal to 5% of the wavelength of the radio wave propagating in the air.
[0015] In the above possible manners, the specific thickness of the dielectric layer is beneficial to avoiding surface wave radiation during signal transmission.
[0016] Based on the above aspects, in a possible implementation method, when observed along the thickness direction, the four sequentially connected edges of each patch are 45° away from the transmission direction of the correspondingly connected coplanar waveguide line, and the two feeding points of each patch respectively correspond to the center positions of the two adjacent edges of the patch, and the line connecting the centers of the two feeding points of the patch is perpendicular to the transmission direction of the correspondingly connected coplanar waveguide line.
[0017] In the above possible manners, the above design is conducive to making the patch generate a magnetic field at 45°, thereby making it difficult for coupling effects to occur between adjacent patches, thereby helping to improve radiation efficiency.
[0018] Based on the above aspects, in a possible implementation, the two feeding points of each patch feed a pair of differential signals from the coplanar waveguide circuit, and the two feeding points on each patch respectively generate vertical electric field polarization and horizontal electric field polarization.
[0019] In the above possible manner, since the current amplitudes of the two feed lines are the same and the phases are opposite, the poles and zeros of the two polarizations are relative, that is, the isolation between the two polarizations is high, cross polarization is not likely to occur, and mutual coupling interference will not occur.
[0020] Based on the above aspects, in a possible implementation, the first conductive layer includes a plurality of patches, the transmission direction of the coplanar waveguide line electrically connected to each patch is the same, the arrangement direction of the plurality of patches is perpendicular to the transmission direction of the coplanar waveguide line, and the spacing between any two adjacent patches is less than the wavelength of the radio wave propagating in the air and greater than half the wavelength of the radio wave propagating in the air.
[0021] In the above possible manner, if the spacing between two adjacent patches is too large, the sidelobe level of the gain pattern of the antenna structure containing multiple patches becomes higher and the gain decreases. If the spacing between two adjacent patches is too small, strong coupling will be generated between the antenna units (corresponding to the patches) in the antenna structure, resulting in mutual interference of electromagnetic fields. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 A schematic diagram of the three-dimensional structure of an antenna structure according to an embodiment of the present application.
[0023] Figure 2 The antenna structure of one embodiment provided in this application is along Figure 1 Schematic diagram of the cross section along the II-II direction.
[0024] Figure 3 A top view of the antenna structure of one embodiment provided in the present application along the thickness direction.
[0025] Main component symbols
[0026]
[0027]
[0028] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION
[0029] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.
[0031] Some embodiments of the present application are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.
[0032] See also Figure 1 and Figure 2 , is an antenna structure 100 of an embodiment provided in the present application. The antenna structure 100 includes a first conductive layer 10, a dielectric layer 30, and a second conductive layer 50 stacked in sequence along the thickness direction X. The first conductive layer 10 includes at least one patch 11, and the patch 11 includes a main body 110, two spaced-apart feeding points 111, and two spaced-apart annular grooves 113. Each of the annular grooves 113 is arranged around one of the feeding points 111 to separate the main body 110 and the feeding point 111. The antenna structure 100 includes two feeding holes 60 corresponding to each of the patches 11, each of the feeding holes 60 passes through the dielectric layer 30, and each of the feeding holes 60 is electrically connected to one of the feeding points 111 at one end, and electrically connected to the second conductive layer 50 at the other end.
[0033] By providing the annular groove 113, the current distribution on the patch 11 is changed, and the current path length is increased, so that the antenna produces a lower resonance point, and the superposition of two adjacent resonance peaks increases the use bandwidth of the antenna structure, thereby achieving the purpose of expanding the bandwidth.
[0034] Furthermore, the second conductive layer 50 may include a coplanar waveguide circuit 51, and one end of each of the feed holes 60 is electrically connected to the coplanar waveguide circuit 51 in the second conductive layer 50 as an excitation source for the patch 11. Since the coplanar waveguide circuit itself has the advantages of low loss and small radiation interference, the signal is directly input to the antenna patch through the feed hole 60, which can reduce the use of balun and thus reduce the signal loss at the front end.
[0035] Further, each of the feeding points 111 may be located at the center of the corresponding annular groove 113 .
[0036] The annular groove 113 may be in a circular ring shape. In other embodiments, the annular groove 113 may also be in other shapes.
[0037] The dielectric layer 30 may include two first dielectric layers 31 stacked along the thickness direction X and a second dielectric layer 33 located between the two first dielectric layers 31 .
[0038] In some embodiments, the Young's modulus of the first dielectric layer 31 may be greater than 5 GPa, and the dielectric constant Dk may be greater than 3.3. Furthermore, the dielectric constant Dk of the second dielectric layer 33 may be less than 2.0, and the dielectric loss factor Df may be less than 0.002. The first dielectric layer 31 is conducive to improving the mechanical properties of the antenna structure, and the second dielectric layer 33 has a lower dielectric constant and dielectric loss factor, which is conducive to the radiation of electromagnetic waves, thereby reducing the Q value, and the bandwidth is inversely proportional to the Q value, that is, it is conducive to increasing the bandwidth.
[0039] In some embodiments, the porosity of the second dielectric layer 33 is greater than the porosity of the first dielectric layer 31. Preferably, the porosity of the first dielectric layer 31 may be 0. Further, the porosity of the second dielectric layer 33 is greater than 10%. In the sandwich-type dielectric layer 30, the two first dielectric layers 31 are provided to improve the stability of the pore structure in the second dielectric layer 33. The pores in the second dielectric layer 33 can introduce air, which usually has a smaller dielectric constant. Therefore, the second dielectric layer 33 with a large porosity is conducive to reducing the dielectric constant, thereby facilitating the expansion of the bandwidth, and at the same time, it is also conducive to reducing the overall weight of the antenna structure 100.
[0040] The material of the first dielectric layer 31 and the material of the second dielectric layer 33 may be the same or different. The material of the first dielectric layer 31 may include but is not limited to polyimide (including modified polyimide, fluorinated polyimide, etc.), epoxy resin, polyurethane, phenolic resin, urea-formaldehyde resin or polyethylene terephthalate, etc. The material of the second dielectric layer 33 may include but is not limited to polyimide (including modified polyimide, fluorinated polyimide, etc.), epoxy resin, polyurethane, phenolic resin, urea-formaldehyde resin or polyethylene terephthalate, etc., wherein the film layer formed by the above materials itself may be a porous film layer. In some embodiments, the material of the second dielectric layer 33 may also include porous materials, such as but not limited to porous ceramic particles, etc.
[0041] Further, in some embodiments, the thickness of each first dielectric layer 31 is defined as h1, the thickness of the second dielectric layer 33 is defined as h2, and the wavelength of the radio wave propagating in the air is λ0, then 2h1+h2≤0.05λ0 can be satisfied. That is, the thickness of the dielectric layer 30 is less than or equal to 0.05λ0, thereby avoiding surface wave radiation during signal transmission.
[0042] Furthermore, the thickness of the second dielectric layer 33 may be greater than the thickness of the first dielectric layer 31, that is, h2>h1. Furthermore, the thickness of the second dielectric layer 33 may be greater than the thickness of the first dielectric layer 31, that is, h2>2h1.
[0043] Observing the first conductive layer 10 along the thickness direction X, the patch 11 may be roughly rectangular. In some embodiments, observing along the thickness direction X, the four edges 11a of the rectangular patch 11 connected in sequence may be 45° to the transmission direction of the correspondingly connected coplanar waveguide line 51, that is, one diagonal of the four corners of the patch 11 is consistent with the transmission direction of the correspondingly connected coplanar waveguide line 51, and the other diagonal is perpendicular to the transmission direction of the correspondingly connected coplanar waveguide line 51. Further, the two feeding points 111 of the patch 11 may respectively correspond to the center positions of the two adjacent edges 11a of the patch 11, and the line connecting the centers of the two feeding points 111 of the patch 11 may be perpendicular to the transmission direction of the correspondingly connected coplanar waveguide line 51. The above design enables the patch to generate a magnetic field at 45°, thereby making it difficult for adjacent patches to produce a coupling effect, which is beneficial to improving radiation efficiency.
[0044] In some embodiments, the two feeding points 111 of the patch 11 can feed a pair of differential signals from the coplanar waveguide line 51 through the two feeding holes 60, and the two feeding points 111 on each patch 11 respectively generate vertical electric field polarization and horizontal electric field polarization. Since the current amplitudes of the two feed lines are the same and the phases are opposite, the poles and zeros of the two polarizations generated are opposite, that is, the isolation between the two polarizations is high, cross polarization is not easy to occur, and mutual coupling interference will not occur.
[0045] In some embodiments, please refer to Figure 3, the first conductive layer 10 includes a plurality of patches 11, and the coplanar waveguide circuit 51 electrically connected to each patch 11 can be arranged in the same direction, that is, the transmission direction of the coplanar waveguide circuit 51 electrically connected to each patch 11 can be the same. The arrangement direction of the plurality of patches 11 can be perpendicular to the transmission direction of the coplanar waveguide circuit 51. Further, the spacing between any two adjacent patches 11 is less than λ0 and greater than 0.5λ0, wherein the spacing between the two patches 11 specifically refers to the distance between the centers of the two patches 11. If the spacing between two adjacent patches 11 is too large, the sidelobe level of the gain pattern of the antenna structure containing the plurality of patches 11 becomes higher and the gain is reduced. If the spacing between two adjacent patches 11 is too small, the antenna units (corresponding to the patches 11) in the antenna structure will be strongly coupled, resulting in mutual interference of electromagnetic fields.
[0046] The above is only the preferred implementation mode of the present application, and is not any form of limitation on the present application. Although the present application has been disclosed as the preferred implementation mode as above, it is not used to limit the present application. Any technician familiar with this profession can make some changes or modify the technical contents disclosed above into equivalent implementation modes without departing from the scope of the technical solution of the present application. However, any simple modification, equivalent change and modification made to the above implementation modes based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.
Claims
1. An antenna structure, comprising a first conductive layer, a dielectric layer and a second conductive layer stacked in sequence along a thickness direction, characterized in that: The first conductive layer includes at least one patch, each of the patch includes a main body, two spaced-apart feeding points and two spaced-apart annular grooves, each of the annular grooves is arranged around one of the feeding points to separate the main body and the feeding point, and the antenna structure includes two feeding holes corresponding to each of the patches, each of the feeding holes passes through the dielectric layer, and one end of each of the feeding holes is electrically connected to a feeding point, and the other end is electrically connected to the second conductive layer.
2. The antenna structure according to claim 1, characterized in that: The second conductive layer includes a coplanar waveguide line, and one end of each of the feeding holes is electrically connected to the coplanar waveguide line.
3. The antenna structure according to claim 2, characterized in that: Each of the feed points is located at the center of the annular groove arranged around the feed point.
4. The antenna structure according to claim 3, characterized in that: The annular groove is in a circular shape, and the patch is in a rectangular shape.
5. The antenna structure according to claim 1, characterized in that: The dielectric layer includes two first dielectric layers stacked along the thickness direction and a second dielectric layer located between the two first dielectric layers, the Young's modulus of the first dielectric layer is greater than 5 Gpa, and the dielectric constant is greater than 3.3; the dielectric constant of the second dielectric layer is less than 2.0, and the dielectric loss factor is less than 0.
002.
6. The antenna structure according to claim 5, characterized in that: The porosity of each of the first medium layers is 0, and the porosity of the second medium layers is greater than 10%.
7. The antenna structure according to claim 5, characterized in that: The thickness of the dielectric layer is less than or equal to 5% of the wavelength of the electric wave propagating in the air.
8. The antenna structure according to claim 4, characterized in that: When observed along the thickness direction, the four sequentially connected edges of each patch are 45° away from the transmission direction of the correspondingly connected coplanar waveguide line, the two feeding points of each patch respectively correspond to the center positions of the two adjacent edges of the patch, and the line connecting the centers of the two feeding points of the patch is perpendicular to the transmission direction of the correspondingly connected coplanar waveguide line.
9. The antenna structure according to claim 2, characterized in that: The two feeding points of each patch feed a pair of differential signals from the coplanar waveguide circuit, and the two feeding points on each patch generate vertical electric field polarization and horizontal electric field polarization respectively.
10. The antenna structure according to claim 2, characterized in that: The first conductive layer includes a plurality of patches, and the transmission direction of the coplanar waveguide line electrically connected to each patch is the same, the arrangement direction of the plurality of patches is perpendicular to the transmission direction of the coplanar waveguide line, and the spacing between any two adjacent patches is less than the wavelength of the radio wave propagating in the air and greater than half the wavelength of the radio wave propagating in the air.