Circularly polarized antenna

Abstract

The invention relates to the field of antennas, in particular to a circularly polarized antenna which comprises a printed board which is a rectangular double-sided copper-clad printed board; the metalized via holes are arranged along the edge of one side of the long edge of the printed board; the conical open grooves are etched in the two sides of the printed board, the number of the conical open grooves is an even number, and the conical open grooves are symmetrically arranged with the center line of one side of the long edge of the printed board as the axis; and the coaxial structure is arranged on one side, close to the metalized via hole, of the middle line of one side of the long edge of the printed board and comprises an inner conductor, a filling medium and a metal sheath, and the inner conductor and the metal sheath are respectively connected with the double-sided copper-clad layer of the printed board. By applying the circularly polarized antenna, the size of the antenna can be reduced to be the same as that of the substrate integrated waveguide, no extra structure occupies space, and the size is reduced by more than 44% compared with that of similar antennas.

Description

Technical Field

[0001] The present application relates to the field of antennas, and in particular to a circularly polarized antenna. Background Art

[0002] Circularly polarized antennas are generally composed of a pair of orthogonal linear polarizations, and the two orthogonal linear polarizations need to have a 90-degree phase difference. In existing planar circularly polarized end-fire antennas, the orthogonal linear polarizations are generally provided by the open aperture of the half-mode substrate integrated waveguide cavity and an electric dipole, respectively. A parallel double wire is required between the two orthogonal linear polarizations to adjust the amplitude ratio and phase difference. Therefore, the antenna size is equal to the direct addition of the three parts, which occupies a large space.

[0003] With the high stealth requirements, high integration and lightweight development of platforms such as aircraft and missiles, antennas must not be higher than the surface of the fuselage or missile body, and the design space left for antennas is getting smaller and smaller. Therefore, the demand for planar end-fire circularly polarized antennas with ultra-low profiles is growing rapidly.

[0004] Conventional planar circularly polarized antennas are side-fire antennas, that is, the maximum beam direction of the antenna is perpendicular to the main plane of the antenna, while the maximum beam direction of the planar end-fire circularly polarized antenna is parallel to the main plane of the antenna, and is suitable for carriers such as aircraft that require the antenna to have a good aerodynamic structure.

[0005] At present, planar end-fire circularly polarized antennas are mainly a combination of substrate integrated waveguide and dipole. The substrate integrated waveguide is used to provide one linear polarization, and the dipole is used to provide another orthogonal linear polarization. The two are connected by parallel double wires to adjust the phase difference. Therefore, the area occupied by the antenna is the direct addition of the three parts, and the size is relatively large.

[0006] In view of this, how to provide a small planar end-fire circularly polarized antenna to meet the demand for an ultra-low profile planar end-fire circularly polarized antenna has become a technical problem that urgently needs to be solved. Summary of the invention

[0007] The embodiment of the present application provides a circularly polarized antenna, which is used to solve the problem that the current demand for an ultra-low-profile planar end-fire circularly polarized antenna cannot be met.

[0008] In a first aspect of an embodiment of the present application, a circularly polarized antenna is provided, including:

[0009] The printed circuit board is a rectangular double-sided copper-clad printed circuit board;

[0010] The metallized vias are arranged along the edge of one side of the long side of the printed circuit board;

[0011] Conical grooves are etched on both sides of the printed circuit board, wherein the number of the conical grooves is an even number of pairs, and they are arranged symmetrically with the midline of one side of the long side of the printed circuit board as the axis;

[0012] The coaxial structure is arranged on the midline of one side of the long side of the printed circuit board and close to the metallized via hole, and includes an inner conductor, a filling medium and a metal sheath, wherein the inner conductor and the metal sheath are respectively connected to the double-sided copper cladding layers of the printed circuit board.

[0013] Optionally, the diameter of the metallized via hole is less than one tenth of the operating wavelength;

[0014] The spacing between adjacent metallized vias is less than twice the diameter of the metallized vias.

[0015] Optionally, the short side size of the rectangular double-sided copper-clad printed circuit board is one quarter of the working wavelength in the medium;

[0016] The long side size of the rectangular double-sided copper-clad printed circuit board is adjusted according to the gain;

[0017] The thickness of the rectangular double-sided copper-clad printed circuit board is adjusted according to the bandwidth.

[0018] Optionally, the number of the tapered slots is adjusted according to the long side size of the printed circuit board.

[0019] Optionally, the slot bevel of the tapered slot is adjusted according to the working bandwidth to obtain an exponential gradient curve or a step gradient line.

[0020] Optionally, the inner conductor is connected to the front copper cladding layer, and the metal outer skin is connected to the bottom copper cladding layer.

[0021] Optionally, the metallized via is used to connect the front copper clad layer and the bottom copper clad layer.

[0022] Optionally, the gain and axial ratio characteristics of the small planar end-fire circularly polarized antenna are adjusted by changing the diameter size and depth of the conical slot;

[0023] The working bandwidth of the small planar end-fire circularly polarized antenna is adjusted by changing the bevel form of the conical slotted bevel, wherein the bevel form includes an exponential gradient curve and a step gradient line.

[0024] The gain of the small planar end-fire circularly polarized antenna is adjusted by changing the length of the printed board and the number of tapered slots.

[0025] Optionally, the circularly polarized antenna is a small planar end-fire circularly polarized antenna.

[0026] The present application provides a circularly polarized antenna, comprising: a printed circuit board, which is a rectangular double-sided copper-clad printed circuit board; metallized vias, which are arranged along the edge of one side of the long side of the printed circuit board; conical slots, which are etched on both sides of the printed circuit board, wherein the number of the conical slots is an even number of pairs, and they are arranged symmetrically with the midline of one side of the long side of the printed circuit board as an axis; a coaxial structure, which is arranged on the midline of one side of the long side of the printed circuit board on one side close to the metallized vias, and comprises an inner conductor, a filling medium and a metal sheath, wherein the inner conductor and the metal sheath are respectively connected to the double-sided copper clad layers of the printed circuit board.

[0027] The circularly polarized antenna provided in the embodiment of the present application can reduce the size of the antenna to the same size as the substrate integrated waveguide, without additional structure occupying space, and the size is reduced by more than 44% compared with similar antennas. The main method is to etch a conical groove in the internal space of the substrate integrated waveguide to introduce another orthogonal polarization, and the orthogonal linear polarization amplitude ratio and phase difference can be adjusted by optimizing the slot size to achieve end-fire circular polarization characteristics.

[0028] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, which can be implemented in accordance with the contents of the specification, and in order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0030] Figure 1 A schematic diagram of a three-dimensional circular polarization antenna provided in an embodiment of the present application;

[0031] Figure 2 A schematic top view of a circularly polarized antenna provided in an embodiment of the present application;

[0032] Figure 3 A bottom view schematic diagram of a circularly polarized antenna provided in an embodiment of the present application;

[0033] Figure 4 A perspective schematic diagram of a circularly polarized antenna provided in an embodiment of the present application;

[0034] Figure 5 A schematic diagram of a reflection coefficient simulation result of a circularly polarized antenna provided in an embodiment of the present application;

[0035] Figure 6A schematic diagram of an axial ratio simulation result of a circularly polarized antenna provided in an embodiment of the present application;

[0036] Figure 7 A schematic diagram of a XOZ plane gain simulation result of a circularly polarized antenna provided in an embodiment of the present application;

[0037] Among them, there are printed circuit board 101, front copper cladding layer 1011, bottom copper cladding layer 1012, metallized via 102, tapered slot 103, coaxial structure 104, inner conductor 1041, filling medium 1042 and metal sheath 1043. DETAILED DESCRIPTION

[0038] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0039] See also Figure 1 , Figure 2 and Figure 3 , Figure 1 A schematic diagram of a three-dimensional circular polarization antenna provided in an embodiment of the present application; Figure 2 A schematic top view of a circularly polarized antenna provided in an embodiment of the present application; Figure 3 A bottom view schematic diagram of a circularly polarized antenna provided in an embodiment of the present application.

[0040] like Figure 1 , Figure 2 and Figure 3 As shown, the circularly polarized antenna provided in the embodiment of the present application is a small planar end-fire circularly polarized antenna, including a printed circuit board 101, a row of metallized vias 102, a conical slot 103 and a coaxial structure 104.

[0041] The printed circuit board 101 is a rectangular double-sided copper-clad printed circuit board, including a front copper-clad layer 1011 and a bottom copper-clad layer 1012 .

[0042] In an embodiment of the present application, the short side dimension of the rectangular double-sided copper-clad printed circuit board is one-quarter of the working wavelength in the medium; the long side dimension of the rectangular double-sided copper-clad printed circuit board is adjusted according to the gain; and the thickness dimension of the rectangular double-sided copper-clad printed circuit board is adjusted according to the bandwidth.

[0043] The metallized vias 102 are arranged along the edge of one side of the long side of the printed circuit board 101. In the embodiment of the present application, each metallized via 102 connects the front copper clad layer 1011 and the bottom copper clad layer 1012, and is used to connect the front copper clad layer 1011 and the bottom copper clad layer 1012.

[0044] In the embodiment of the present application, the metallized via 102 should be as close as possible to any long edge of the rectangular printed circuit board 101, and the diameter of the metallized via 102 is less than one tenth of the working wavelength; the spacing between adjacent metallized vias 102 is less than twice the diameter of the metallized via 102.

[0045] Conical grooves 103 are etched on both sides of the printed circuit board 101, wherein the number of the conical grooves 103 is an even number of pairs, and they are arranged symmetrically with the midline of one side of the long side of the printed circuit board 101 as the axis. In the embodiment of the present application, the conical grooves 103 include four conical grooves 103 on the front copper cladding layer 1011 and four conical grooves 103 on the bottom copper cladding layer 1012. Figure 4 , Figure 4 A perspective view of a circularly polarized antenna provided in an embodiment of the present application is shown in FIG. Figure 4 As shown, the four tapered slots 103 on the front copper cladding layer 1011 and the four tapered slots 103 on the bottom copper cladding layer 1012 are symmetrically placed from a top view, forming four pairs of tapered slot antenna structures.

[0046] In the embodiment of the present application, the number of the tapered slots 103 is adjusted according to the long side size of the printed circuit board 101. It should be noted that the number of the tapered slots 103 includes at least two pairs.

[0047] The slot bevel of the tapered slot 103 is adjusted according to the working bandwidth to obtain an exponential gradient curve or a step gradient line.

[0048] The coaxial structure 104 is arranged on the middle line of one side of the long side of the printed circuit board 101 and close to the metallized via 102, and includes an inner conductor 1041 (also called a metal coaxial inner core), a filling medium 1042 and a metal outer skin 1043, wherein the inner conductor 1041 and the metal outer skin 1043 are respectively connected to the double-sided copper cladding of the printed circuit board 101. That is, the inner conductor 1041 is connected to the front copper cladding 1011, and the metal outer skin 1043 is connected to the bottom copper cladding 1012.

[0049] In the embodiment of the present application, the inner conductor 1041 is connected to the front copper cladding layer 1011 , and the metal outer skin 1043 is connected to the bottom copper cladding layer 1012 .

[0050] See also Figure 5 , Figure 6 and Figure 7,in, Figure 5 A schematic diagram of a reflection coefficient simulation result of a circularly polarized antenna provided in an embodiment of the present application; Figure 6 A schematic diagram of an axial ratio simulation result of a circularly polarized antenna provided in an embodiment of the present application; Figure 7 A schematic diagram of the XOZ plane gain simulation results of a circularly polarized antenna provided in an embodiment of the present application. The antenna is verified at 2.4 GHz frequency, and the reflection coefficient modulus of the antenna at 2.4 GHz is ≤-15 dB, and effective circularly polarized radiation is generated in the end-fire +Z direction, with an axial ratio of ≤1 dB.

[0051] In the embodiment of the present application, when in use, the circularly polarized antenna gain and axial ratio characteristics can be adjusted by changing the diameter size and depth of the conical slot 103; the antenna operating bandwidth can be adjusted by changing the form of the conical slot hypotenuse to an exponential gradient curve, a step gradient line, etc., and the thickness of the printed circuit board 101; the circularly polarized antenna gain can be adjusted by changing the length of the printed circuit board 101 and the number of conical slots.

[0052] By using the circularly polarized antenna provided in the embodiment of the present application, it is possible to utilize the internal space of the substrate integrated waveguide cavity, etch the conical slot 103 to introduce another orthogonal polarization, and adjust the orthogonal linear polarization amplitude ratio and phase difference by adjusting the slot size to achieve end-fire circular polarization characteristics. Therefore, the overall size of the antenna is equal to the size of the substrate integrated waveguide, and is no longer the sum of the structural sizes of the substrate integrated waveguide, another orthogonal linear polarization, and the parallel dual conductors, effectively reducing the antenna volume by more than 44%.

[0053] It should be noted that the above is a description of a specific embodiment of the present specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the embodiments of the present specification.

[0054] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0055] The preferred embodiments of this specification disclosed above are only used to help explain this specification. The optional embodiments do not describe all the details in detail, nor do they limit the invention to only the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of the embodiments of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the embodiments of this specification, so that technicians in the relevant technical field can well understand and use this specification. This specification is only limited by the claims and their full scope and equivalents.

Claims

1. A circularly polarized antenna, characterized in that: include: The printed circuit board is a rectangular double-sided copper-clad printed circuit board; The metallized vias are arranged along the edge of one side of the long side of the printed circuit board; Conical grooves are etched on both sides of the printed circuit board, wherein the number of the conical grooves is an even number of pairs, and they are arranged symmetrically with the midline of one side of the long side of the printed circuit board as the axis; The coaxial structure is arranged on the midline of one side of the long side of the printed circuit board and close to the metallized via hole, and includes an inner conductor, a filling medium and a metal sheath, wherein the inner conductor and the metal sheath are respectively connected to the double-sided copper cladding layers of the printed circuit board.

2. The circularly polarized antenna according to claim 1, characterized in that: The diameter of the metallized via hole is less than one tenth of the operating wavelength; The distance between adjacent metallized vias is less than twice the diameter of the metallized vias.

3. The circularly polarized antenna according to claim 1, characterized in that: The short side size of the rectangular double-sided copper-clad printed circuit board is one quarter of the working wavelength in the medium; The long side size of the rectangular double-sided copper-clad printed circuit board is adjusted according to the gain; The thickness of the rectangular double-sided copper-clad printed circuit board is adjusted according to the bandwidth.

4. The circularly polarized antenna according to claim 1, characterized in that: The number of the tapered slots is adjusted according to the long side size of the printed circuit board.

5. The circularly polarized antenna according to claim 1, characterized in that: The slotting bevel of the tapered slotting is adjusted according to the working bandwidth to obtain an exponential gradient curve or a step gradient line.

6. The circularly polarized antenna according to claim 1, characterized in that: The inner conductor is connected to the front copper cladding layer, and the metal outer skin is connected to the bottom copper cladding layer.

7. The circularly polarized antenna according to claim 1, characterized in that: The metallized via is used to connect the front copper clad layer and the bottom copper clad layer.

8. The circularly polarized antenna according to claim 1, characterized in that: The gain and axial ratio characteristics of the small planar end-fire circularly polarized antenna are adjusted by changing the diameter and depth of the conical slot; The working bandwidth of the small planar end-fire circularly polarized antenna is adjusted by changing the bevel form of the conical slotted bevel, wherein the bevel form includes an exponential gradient curve and a step gradient line. The gain of the small planar end-fire circularly polarized antenna is adjusted by changing the length of the printed board and the number of tapered slots.

9. The circularly polarized antenna according to claim 1, characterized in that: The circularly polarized antenna is a small planar end-fire circularly polarized antenna.

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