Circular polarizer, radio frequency antenna and radio frequency identification reading device
By using circular polarizers with first and second fold lines arranged in a cross-layered manner, the problem of complex structure of circular polarized antennas in the prior art is solved, achieving efficient conversion of linearly polarized beams to circularly polarized beams, improving circular polarization performance and simplifying the structure.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- INVENGO INFORMATION TECH
- Filing Date
- 2025-06-19
- Publication Date
- 2026-07-24
AI Technical Summary
Existing circularly polarized antennas have complex structures, making it difficult to efficiently convert linearly polarized beams into circularly polarized beams.
A circular polarizer with a first and second zigzag cross-layer arrangement is used to guide the linearly polarized beam to radiate in an orthogonal direction, converting it into a circularly polarized beam, reducing the axial ratio and improving the circular polarization performance.
It achieves efficient conversion from linearly polarized beams to circularly polarized beams, improves circular polarization performance, simplifies the structure, reduces feed grid loss, and improves radiation efficiency.
Smart Images
Figure CN224554719U_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of communication technology, and more specifically, relates to a circular polarizer, a radio frequency antenna, and a radio frequency identification reading device. Background Technology
[0002] Currently, UHF RFID technology is mainly used for rapid identification of single / multiple product tags in retail, warehousing, and logistics applications. The reader antenna primarily uses a circularly polarized antenna for radiation to facilitate matching the polarization of the tag antenna in various directions. However, the circularly polarized antennas in this technology suffer from structural complexity. Utility Model Content
[0003] The purpose of this application is to provide a circular polarizer, a radio frequency antenna, and a radio frequency identification reading device to solve the technical problem of the complex structure of circular polarized antennas in the prior art.
[0004] In one aspect, this application provides a circular polarizer.
[0005] The circular polarizer provided in this application includes a first zigzag line and a second zigzag line. The first zigzag line extends along a first direction, and the second zigzag line extends along a second direction. The first direction is orthogonal to the second direction, and the first zigzag line and the second zigzag line are stacked along a third direction. The third direction is orthogonal to the first direction and the third direction is orthogonal to the second direction. The radiation direction of the linearly polarized beam extends along the third direction.
[0006] The beneficial effects of the circular polarizer provided in this application are as follows: Compared with the prior art, the first and second fold lines of the circular polarizer provided in this application can respectively guide the linearly polarized beam to radiate in a direction orthogonal to its original radiation direction, thereby converting the linearly polarized beam into a circularly polarized beam. The extension direction of the first fold line is orthogonal to the extension direction of the second fold line, which reduces the axial ratio of the circularly polarized beam formed by the circular polarizer provided in this application and improves the circular polarization performance of the circularly polarized beam emitted by the circular polarizer.
[0007] Optionally, the first broken line includes a plurality of first segments and a plurality of second segments that are alternately connected in sequence, wherein the first segments are parallel to the first direction and the second segments are parallel to the second direction;
[0008] The second broken line includes a plurality of third segments and a plurality of fourth segments that are alternately connected in sequence. The third segments are parallel to the second direction, and the fourth segments are parallel to the first direction.
[0009] Optionally, the first segment and the third segment have the same length, and the ratio of the length of the first segment to the center wavelength of the linearly polarized beam is 0.24-0.26.
[0010] The second segment and the fourth segment have the same length, and the ratio of the length of the second segment to the center wavelength of the linearly polarized beam is 0.24-0.26.
[0011] Optionally, the extension direction of the first broken line has an angle with the polarization direction of the linearly polarized beam, and the extension direction of the second broken line has an angle with the polarization direction of the linearly polarized beam.
[0012] Optionally, there are multiple first lines and multiple second lines, with the multiple first lines and multiple second lines arranged alternately along the third direction.
[0013] Optionally, the distance between the first and second adjacent polygonal lines on the third side is less than one-tenth of the center wavelength of the linearly polarized beam.
[0014] Optionally, the circular polarizer further includes a dielectric substrate, with one of the first and second fold lines adjacent to each other in the third direction disposed on the surface of the dielectric substrate on the third-direction upward side, and / or, with the other of the first and second fold lines adjacent to each other in the third direction disposed on the surface of the dielectric substrate on the other side in the third-direction upward side.
[0015] Optionally, there are multiple dielectric substrates, which are arranged parallel and spaced apart along the third direction, so that the first fold line or the second fold line can be sandwiched between two adjacent dielectric substrates, and a support is also sandwiched between two adjacent dielectric substrates.
[0016] Secondly, this application provides a radio frequency antenna.
[0017] The radio frequency antenna provided in this application includes a radiator and a circular polarizer. The radiator is used to generate a linearly polarized beam that radiates along the third direction as described in any of the above embodiments. The circular polarizer is the circular polarizer described in any of the above embodiments, and the circular polarizer and the radiator are arranged at intervals along the third direction.
[0018] The beneficial effects of the radio frequency antenna provided in this application are as follows: Compared with the prior art, the radio frequency antenna provided in this application uses a circular polarizer to convert the linearly polarized beam generated by the radiator into a circularly polarized beam. When the radio frequency antenna provided in this application is working, the radiator first generates a linearly polarized beam, and then the circular polarizer converts the linearly polarized beam into a circularly polarized beam. Compared with the antennas in related technologies that directly generate circularly polarized beams, the radio frequency antenna provided in this application has the advantages of higher beam quality and simpler structure, thus giving it the advantages of higher circular polarization and simpler structure.
[0019] Optionally, the ratio of the distance between the radiator and the circular polarizer in the third direction to the center wavelength of the linearly polarized beam is 2.5-3.5.
[0020] Thirdly, this application provides a radio frequency identification (RFID) reading device.
[0021] The radio frequency identification (RFID) reading device provided in this application includes the radio frequency antenna described in any of the above embodiments.
[0022] It is understandable that the beneficial effects of the third aspect mentioned above can be found in the relevant descriptions in the second aspect above, and will not be repeated here. Attached Figure Description
[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0024] Figure 1 A schematic diagram of the structure of the circular polarizer provided in the embodiments of this application. Figure 1 ;
[0025] Figure 2 A schematic diagram of the structure of the circular polarizer provided in the embodiments of this application. Figure 2 ;
[0026] Figure 3 Equivalent circuit of the circular polarizer provided in the embodiments of this application Figure 1 ;
[0027] Figure 4 Equivalent circuit of the circular polarizer provided in the embodiments of this application Figure 2 ;
[0028] Figure 5 Equivalent circuit of the circular polarizer provided in the embodiments of this application Figure 3 ;
[0029] Figure 6 This is a schematic diagram of the structure of the radio frequency antenna provided in the embodiments of this application;
[0030] Figure 7 This is a schematic diagram of the feed grid structure of the radio frequency antenna provided in the embodiments of this application;
[0031] Figure 8 This is a schematic diagram of the structure of the radio frequency identification reading device provided in the embodiments of this application.
[0032] The following are the labeling elements in the figure:
[0033] 100. Circular polarizer;
[0034] 10. First broken line; 11. First segment; 12. Second segment;
[0035] 20. Second broken line; 21. Third segment; 22. Fourth segment;
[0036] 30. Dielectric substrate; 31. First surface; 32. Second surface;
[0037] 40. Bracket;
[0038] 200. Radiator;
[0039] 300, Feeder net;
[0040] 400. Motherboard;
[0041] a) Linearly polarized beam; b) Circularly polarized beam. Detailed Implementation
[0042] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.
[0043] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.
[0044] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.
[0045] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.
[0046] This application provides a circular polarizer 100, a radio frequency antenna using the circular polarizer 100, and a radio frequency identification (RFID) reader using the radio frequency antenna. The circular polarizer 100 provided in this application can be used to convert a linearly polarized beam a into a circularly polarized beam b.
[0047] Please refer to the following: Figure 1 , Figure 2 and Figure 6 The radio frequency antenna provided in the embodiments of this application will now be described.
[0048] It should be noted that the first direction in the following text is the x-direction shown in the figure, the second direction in the following text is the y-direction shown in the figure, and the third direction in the following text is the z-direction shown in the figure.
[0049] The circular polarizer 100 provided in this application includes a first zigzag line 10 and a second zigzag line 20. The first zigzag line 10 extends along a first direction x, and the second zigzag line 20 extends along a second direction y. The first direction x and the second direction y are orthogonal, and the first zigzag line 10 and the second zigzag line 20 are stacked along a third direction z. The third direction z is orthogonal to the first direction x and the second direction y. Figure 6 As shown, the radiation direction of the linearly polarized beam a extends along the third direction z. It should be noted that... Figure 6 The arrow in the diagram indicates the polarization direction of the linearly polarized beam a, and the radiation direction of the linearly polarized beam a is... Figure 6 The z-direction is shown in the figure.
[0050] In some embodiments, the first broken line 10 and the second broken line 20 are metallic structures, such that when the linearly polarized beam a passes through the first broken line 10 or the second broken line 20 along a third direction z, at least a portion of the linearly polarized beam a is captured by the first broken line 10 or the second broken line 20 and radiates again after being propagated therein.
[0051] like Figure 1 As shown, the first broken line 10 includes multiple sequentially connected first broken line segments. These multiple first broken lines are arranged along a first direction x, such that the first broken line 10 extends along the first direction x, and any two adjacent first broken line segments have an included angle. When the linearly polarized beam a is propagated from one of two adjacent first broken line segments to the other, a shape is formed between the two adjacent first broken line segments as shown in the diagram. Figure 3 The equivalent circuit shown or such Figure 4 The equivalent circuit shown guides a portion of the linearly polarized beam a to radiate in a direction orthogonal to its original radiation direction, thereby converting the linearly polarized beam a into a circularly polarized beam b.
[0052] Similarly, the second broken line 20 includes multiple sequentially connected second broken lines, with multiple second broken line segments arranged along the second direction y, so that the second broken line 20 extends along the second direction y, and there is an angle between any two adjacent second broken line segments. When the linearly polarized beam a is propagated from one of two adjacent second broken line segments to the other, a shape is formed between the two adjacent second broken line segments as follows: Figure 3 The equivalent circuit shown or such Figure 4 The equivalent circuit shown guides a portion of the linearly polarized beam a to radiate in a direction orthogonal to its original radiation direction, thereby converting the linearly polarized beam a into a circularly polarized beam b.
[0053] Therefore, as Figure 6 As shown, when the linearly polarized beam a passes through either the first broken line 10 or the second broken line 20 along the third direction z, the first broken line 10 or the second broken line 20 can absorb part of the energy of the linearly polarized beam a and guide it to deflect in a direction orthogonal to the original polarization direction of the linearly polarized beam a, thereby realizing circularly polarized radiation.
[0054] The first broken line 10 and the second broken line 20 are stacked along the third direction z, and the extension direction of the first broken line 10 and the extension direction of the second broken line 20 are orthogonal, so that the linearly polarized beam a can pass through the first broken line 10 and the second broken line 20 in sequence along the third direction z, thereby reducing the axial ratio of the circularly polarized beam b generated by the circularly polarized beam b and improving the circular polarization effect.
[0055] The beneficial effects of the circular polarizer 100 provided in this application are as follows: Compared with the prior art, the first broken line 10 and the second broken line 20 of the circular polarizer 100 provided in this application can respectively guide the linearly polarized beam a to radiate in a direction orthogonal to its original radiation direction, thereby changing the linearly polarized beam a into a circularly polarized beam b. The extension direction of the first broken line 10 is orthogonal to the extension direction of the second broken line 20, thereby reducing the axial ratio of the circularly polarized beam b formed by the circular polarizer 100 provided in this application and improving the circular polarization performance of the circularly polarized beam b emitted by the circular polarizer 100.
[0056] The circular polarizer 100 provided in this application does not require any changes to the structure of the antenna feed 300 or the radiator 200, and has the advantage of being able to convert a linearly polarized beam a into a circularly polarized beam b.
[0057] In some embodiments provided in this application, there are multiple first broken lines 10, which are arranged parallel to and spaced apart along the second direction y, and there are multiple second broken lines 20, which are arranged parallel to and spaced apart along the first direction z.
[0058] In some embodiments provided in this application, the first broken line 10 includes a plurality of first segments 11 and a plurality of second segments 12 that are alternately connected in sequence. The first segments 11 extend along a first direction x, and the second segments 12 extend along a second direction y.
[0059] like Figure 1 As shown, the first broken line segment includes a first segment 11 extending along a first direction x and a second segment 12 extending along a second direction y. Multiple first segments 11 and multiple second segments 12 are arranged alternately along the first direction x to form a first broken line 10 by connecting and combining multiple first segments 11 and second segments 12.
[0060] When the linearly polarized beam a passes through the first broken line 10 along the third direction z, at least part of the energy of the linearly polarized beam a is captured by the first broken line 10 to form an electrical signal that is conducted within the first broken line 10. The electrical signal is conducted alternately between the first segment 11 and the second segment 12.
[0061] The equivalent circuit when the electrical signal is transmitted from the first segment 11 to the second segment 12 is as follows: Figure 3 As shown, the phase of the electrical signal deflects by -90° when it travels from the first segment 11 to the second segment 12. The equivalent circuit when the electrical signal travels from the second segment 12 to the first segment 11 is as follows. Figure 4 As shown, the electrical signal deflects by 90° when it travels from the second segment 12 to the first segment 11. Figure 5 As shown, when the electrical signal is propagated along the first direction x in the first broken line 10, it undergoes periodic phase deflection and polarization adjustment through the first broken line 10, so that the linearly polarized beam a can achieve the transformation from linear polarization to circular polarization.
[0062] The second broken line 20 includes a plurality of third segments 21 and a plurality of fourth segments 22 that are connected alternately in sequence. The third segments 21 extend along the second direction y, and the fourth segments 22 extend along the first direction x.
[0063] like Figure 1 As shown, the second broken line segment includes a third segment 21 extending along the second direction y and a fourth segment 22 extending along the first direction x. Multiple third segments 21 and multiple fourth segments 22 are arranged alternately along the second direction y to form a first broken line 10 by connecting and combining multiple third segments 21 and fourth segments 22.
[0064] When the linearly polarized beam a passes through the first broken line 10 along the third direction z, at least part of the energy of the linearly polarized beam a is captured by the first broken line 10 to form an electrical signal that is conducted within the first broken line 10. The electrical signal is conducted alternately between the third segment 21 and the fourth segment 22.
[0065] The equivalent circuit when the electrical signal is transmitted from the third segment 21 to the fourth segment 22 is as follows: Figure 3 As shown, the phase of the electrical signal deflects by -90° when it travels from the third segment 21 to the fourth segment 22. The equivalent circuit when the electrical signal travels from the fourth segment 22 to the third segment 21 is as follows. Figure 4 As shown, the electrical signal deflects by 90° when it travels from the fourth segment 22 to the third segment 21. Figure 5As shown, when the electrical signal is propagated along the second direction y in the first broken line 10, it undergoes periodic phase deflection and polarization adjustment through the first broken line 10, so that the linearly polarized beam a can achieve the transformation from linear polarization to circular polarization.
[0066] In some embodiments provided in this application, the first segment 11 and the third segment 21 have the same length, and the ratio of the length of the first segment 11 to the center wavelength of the linearly polarized beam a is 0.24-0.26.
[0067] The second segment 12 and the fourth segment 22 have the same length, and the ratio of the length of the second segment 12 to the center wavelength of the linearly polarized beam a is 0.24-0.26.
[0068] The length of the broken line segment is designed according to the frequency band of the single-polarized beam. The length of the broken line segment is one-quarter of the center wavelength of the linearly polarized beam a. That is, the length of the first segment 11, the second segment 12, the third segment 21 and the fourth segment 22 are all one-quarter of the wavelength corresponding to the center frequency of the linearly polarized beam a. Therefore, when the electrical signal is propagated in any one of the first segment 11, the second segment 12, the third segment 21 and the fourth segment 22, a phase deflection of 90° can be achieved.
[0069] like Figure 1 As shown, the length of the first segment 11 is the same as that of the third segment 21, and the length of the second segment 12 is the same as that of the fourth segment 22, so that the first broken line 10 and the second broken line 20 have the same shape, thereby reducing the axial ratio of the circularly polarized beam b emitted by the circular polarizer 100 and improving the circular polarization effect of the circularly polarized beam b.
[0070] In some embodiments, the length of the first segment 11 is the same as the length of the second segment 12. In other embodiments, the length of the first segment 11 is different from the length of the second segment 12.
[0071] In some embodiments provided in this application, the extension direction of the first broken line 10 is at an angle to the polarization direction of the linearly polarized beam a, and the extension direction of the second broken line 20 is at an angle to the polarization direction of the linearly polarized beam a.
[0072] like Figure 1 As shown, the polarization direction of the linearly polarized beam a is along... Figure 1As shown in c, the polarization direction of the linearly polarized beam a intersects with the extension direction of the first segment 11 and the extension direction of the second segment 12, so that a portion of the linearly polarized beam a can be captured by the first segment 11, a portion of the linearly polarized beam a can be captured by the second segment 12, a portion of the linearly polarized beam a can be captured by the third segment 21, and a portion of the linearly polarized beam a can be captured by the fourth segment 22. This increases the deflection effect of the first broken line 10 and the second broken line 20 on the polarization direction of the linearly polarized beam a, and improves the circular polarization effect of the circular polarizer 100 provided in this application.
[0073] In some embodiments, the angle between the polarization direction of the linearly polarized beam a and the extension direction of the first broken line 10 is the same as the angle between the polarization direction of the linearly polarized beam a and the extension direction of the second broken line 20, so that the guiding effect of the first broken line 10 on the beam polarization direction is the same as the guiding effect of the second broken line 20 on the beam polarization direction, thereby making the circularly polarized beam b after conversion by the circular polarizer 100 provided in this application have a smaller axial ratio.
[0074] In some embodiments provided in this application, there are multiple first broken lines 10 and multiple second broken lines 20, and the multiple first broken lines 10 and multiple second broken lines 20 are arranged alternately along a third direction z.
[0075] Multiple first broken lines 10 extend along a first direction x, and multiple second broken lines 20 extend along a second direction y. The multiple first broken lines 10 and multiple second broken lines 20 are alternately arranged along a third direction z. The multiple first broken lines 10... Figure 1 The orthographic projections in the xOy plane shown coincide, and multiple second polygonal lines 20 are in Figure 1 The orthographic projections in the xOy plane shown in the figure coincide.
[0076] Therefore, when the linearly polarized beam a radiates along the third direction z, the linearly polarized beam a passes through multiple first broken lines 10 and multiple second broken lines 20 in sequence, thereby improving the conversion rate of the circularly polarized beam a by the circularly polarized beam 100 and further reducing the axial ratio of the circularly polarized beam b after conversion by the circularly polarized beam 100 provided in this application.
[0077] In some embodiments provided in this application, such as Figure 2 and Figure 6 As shown, the number of the first broken line 10 is the same as the number of the second broken line 20.
[0078] In some other embodiments provided in this application, the number of first broken lines 10 is different from the number of second broken lines 20.
[0079] In some embodiments provided in this application, the distance between the first fold line 10 and the second fold line 20 adjacent to each other on the third direction z is less than one-tenth of the center wavelength of the linearly polarized beam a.
[0080] In some embodiments provided in this application, the circular polarizer 100 also includes a dielectric substrate 30.
[0081] In some embodiments, the dielectric substrate 30 is spaced between adjacent first fold lines 10 and second fold lines 20. The dielectric substrate 30 has a first surface 31 and a second surface 32 arranged in parallel and spaced apart in a third direction z. One of the adjacent first fold lines 10 and second fold lines 20 in the third direction z is disposed on the first surface 31, and the other of the adjacent first fold lines 10 and second fold lines 20 in the third direction z is disposed on the second surface 32.
[0082] In other embodiments, the dielectric substrate 30 has a first fold line 10 or a second fold line 20 only on one side along the third direction z.
[0083] The dielectric substrate 30 may be made of one or more materials with low dielectric constant, such as FR4 (epoxy resin-based glass fiber composite material), RO4003C (glass cloth reinforced, ceramic-filled hydrocarbon material), etc.
[0084] like Figure 1 As shown, the first surface 31 and the second surface 32 both extend along the xOy plane. The first fold line 10 and the second fold line 20 adjacent to each other in the third direction z are respectively provided on the two surfaces of the dielectric substrate 30 in the third direction z. The distance between the first fold line 10 and the second fold line 20 adjacent to each other in the third direction z is the thickness dimension of the dielectric substrate 30 in the third direction z.
[0085] Therefore, the thickness of the dielectric substrate 30 in the third direction z is less than one-tenth of the wavelength corresponding to the center frequency of the linearly polarized beam a, which can reduce the influence of surface waves generated between the first fold line 10 and the adjacent second fold line 20 on the radiation power output of the circular polarizer 100.
[0086] In some embodiments, the dielectric constant of the dielectric substrate 30 is 2.4-2.8, and the thickness of the dielectric substrate 30 in the third direction z is 4.5 mm.
[0087] In some embodiments provided in this application, there are multiple dielectric substrates 30, which are arranged parallel to each other and spaced apart along a third direction z, so that the first fold line 10 or the second fold line 20 can be sandwiched between two adjacent dielectric substrates 30, and a support 40 is also sandwiched between two adjacent dielectric substrates 30.
[0088] like Figure 2As shown, one end of the support 40 in the third direction z abuts against one of the two adjacent dielectric substrates 30, and the other end of the support 40 in the third direction z abuts against the other of the two adjacent dielectric substrates 30. When the two adjacent dielectric substrates 30 move toward each other, the support 40 abuts against the two adjacent dielectric substrates 30 to protect the first fold line 10 or the second fold line 20 between the two adjacent dielectric substrates 30.
[0089] The following is combined Figure 6 and Figure 7 This application describes the radio frequency antenna provided.
[0090] The radio frequency antenna provided in this application includes a radiator 200 and a circular polarizer 100. The radiator 200 is used to generate a linearly polarized beam a radiated along the third direction z in any of the above embodiments. The circular polarizer 100 is the circular polarizer 100 in any of the above embodiments, and the circular polarizer 100 and the radiator 200 are arranged at intervals along the third direction z.
[0091] like Figure 7 As shown, the radiator 200 can be an antenna such as a dipole or patch that can generate a linearly polarized beam a. The radiator 200 can generate electromagnetic oscillations inside it under the excitation of a signal source, thereby transmitting a beam. When the electromagnetic oscillation inside the radiator 200 extends in a single direction, the radiator 200 can emit a linearly polarized beam a.
[0092] In some embodiments, as shown in the figure, the radiator 200 is a patch array consisting of multiple patches. The radiator 200 is connected to the feed grid 300. There is only one connection point between the feed grid 300 and each radiator 200, and the connection positions of the feed grid 300 and the multiple patches are all the same, so that the multiple patches generate a linearly polarized beam a polarized in the same direction.
[0093] Therefore, compared with the circular polarization radiation achieved by cross-polarized antennas in related technologies, the radio frequency antenna provided in this application only generates linear polarization radiation, which simplifies the structure of the feed grid 300, thereby reducing the loss noise generated in the feed grid 300 and improving the radiation efficiency of the radio frequency antenna.
[0094] The beneficial effects of the radio frequency antenna provided in this application are as follows: Compared with the prior art, the radio frequency antenna provided in this application uses a circular polarizer 100 to convert the linearly polarized beam a generated by the radiator 200 into a circularly polarized beam b. When the radio frequency antenna provided in this application is working, the radiator 200 first generates a linearly polarized beam a, and then the circular polarizer 100 converts the linearly polarized beam a into a circularly polarized beam b. Compared with the antennas in related technologies that directly generate a circularly polarized beam b, the radio frequency antenna provided in this application has the advantages of higher beam quality and simpler structure, thus giving the radio frequency antenna provided in this application the advantages of higher circular polarization and simpler structure.
[0095] In some embodiments provided in this application, the ratio of the distance between the radiator 200 and the circular polarizer 100 in the third direction z to the center wavelength of the linearly polarized beam a is 2.5-3.5.
[0096] As shown in the figure, the distance between the radiator 200 and the circular polarizer 100 in the third direction z is 3 times the wavelength corresponding to the center frequency of the linearly polarized beam a generated by the radiator 200.
[0097] Therefore, at distances from the radiator 200 at three corresponding wavelengths, the propagation characteristics of electromagnetic waves are relatively stable and not easily affected by nearby objects, thus avoiding direct interference between the circular polarizer 100 and the radiator 200.
[0098] The following is combined Figure 8 This application introduces the radio frequency identification (RFID) reading device provided.
[0099] The radio frequency identification (RFID) reading device provided in this application includes the radio frequency antenna in any of the above embodiments.
[0100] like Figure 8 As shown, the radio frequency identification reading device provided in this application also includes a motherboard 400, which is electrically connected to the radiator 200 of the radio frequency antenna so as to input an electrical signal to the radiator 200 through the motherboard 400, thereby exciting the radiator 200 to generate a linearly polarized beam a.
[0101] The RFID reading device provided in this application uses the RFID antenna provided in this application. The RFID antenna provided in this application radiates a circularly polarized beam b by converting the linearly polarized beam a generated by the radiator 200 into a circularly polarized beam b through a circular polarizer 100. This gives the RFID antenna provided in this application the advantages of high radiation efficiency and low manufacturing cost. Consequently, the RFID reading device provided in this application can radiate and receive RFID signals in a circularly polarized manner while also having the advantages of high radiation efficiency and low manufacturing cost.
[0102] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A circular polarizer for guiding an incident linearly polarized beam into a circularly polarized beam, characterized in that, include: A first zigzag line and a second zigzag line, wherein the first zigzag line extends along a first direction and the second zigzag line extends along a second direction, the first direction and the second direction are orthogonal, and the first zigzag line and the second zigzag line are stacked along a third direction, the third direction is orthogonal to the first direction and the third direction is orthogonal to the second direction, and the radiation direction of the linearly polarized beam extends along the third direction.
2. The circular polarizer as described in claim 1, characterized in that: The first broken line includes a plurality of first segments and a plurality of second segments that are alternately connected in sequence, wherein the first segments are parallel to the first direction and the second segments are parallel to the second direction; The second broken line includes a plurality of third segments and a plurality of fourth segments that are alternately connected in sequence. The third segments are parallel to the second direction, and the fourth segments are parallel to the first direction.
3. The circular polarizer as described in claim 1, characterized in that: The first segment and the third segment have the same length, and the ratio of the length of the first segment to the center wavelength of the linearly polarized beam is 0.24-0.
26. The second segment and the fourth segment have the same length, and the ratio of the length of the second segment to the center wavelength of the linearly polarized beam is 0.24-0.
26.
4. The circular polarizer as described in claim 2, characterized in that: The extension direction of the first broken line forms an angle with the polarization direction of the linearly polarized beam, and the extension direction of the second broken line forms an angle with the polarization direction of the linearly polarized beam.
5. The circular polarizer as described in claim 2, characterized in that: There are multiple first broken lines and multiple second broken lines, and the multiple first broken lines and multiple second broken lines are arranged alternately along the third direction.
6. The circular polarizer as described in claim 5, characterized in that: The distance between the first and second adjacent polygonal lines on the third side is less than one-tenth of the center wavelength of the linearly polarized beam.
7. The circular polarizer as described in any one of claims 1-6, characterized in that: The circular polarizer further includes a dielectric substrate, wherein one of the first and second fold lines adjacent to each other in the third direction is disposed on the surface of the dielectric substrate on the third-direction upward side, and / or, the other of the first and second fold lines adjacent to each other in the third direction is disposed on the surface of the dielectric substrate on the other side in the third direction.
8. The circular polarizer as described in claim 7, characterized in that: There are multiple dielectric substrates, which are arranged parallel to each other and spaced apart along the third direction, so that the first fold line or the second fold line can be sandwiched between two adjacent dielectric substrates, and a support is also sandwiched between two adjacent dielectric substrates.
9. A radio frequency antenna, characterized in that, include: A radiator for generating a linearly polarized beam radiating in any one of claims 1-8; A circular polarizer, wherein the circular polarizer is as described in any one of claims 1-8, and the circular polarizer and the radiator are arranged at a distance along the third direction.
10. The radio frequency antenna as described in claim 9, characterized in that: The ratio of the distance between the radiator and the circular polarizer in the third direction to the center wavelength of the linearly polarized beam is 2.5-3.
5.
11. A radio frequency identification (RFID) reading device, characterized in that: Includes the radio frequency antenna as described in any one of claims 9-10.