Broadband Circularly Polarized Planar End-Fire Antenna Based on Substrate Integrated Waveguide

Abstract

The present invention provides a broadband circularly polarized planar end-fire antenna based on substrate integrated waveguide, which includes a wave port, a substrate integrated waveguide and a dipole antenna; the wave port is connected to one side of the dielectric substrate away from the dipole antenna, and is used to generate an excitation signal through feeding to drive the electromagnetic wave transmission in the substrate integrated waveguide, so that the substrate integrated waveguide generates a vertically polarized electric field component and the dipole antenna generates a horizontally polarized electric field component; by adjusting the amplitude-phase relationship between the two orthogonally polarized electric field components, broadband circularly polarized radiation is realized. The present invention does not require an additional radiation structure to compensate for the vertical polarization component, avoiding the increase in profile height due to the addition of an additional structure, realizing a low-profile design, and making the structure of the broadband circularly polarized planar end-fire antenna more compact; the dipole antenna is directly connected to the upper metal plate and the lower metal plate, greatly reducing the overall size of the antenna, reducing the occupied space, simplifying the manufacturing process, and reducing the production process and material cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of millimeter-wave antennas, and particularly relates to a broadband circularly polarized planar end-fire antenna based on substrate integrated waveguide. Background Art

[0002] Circularly polarized antennas have advantages in terms of mobility, flexibility, weather penetration, and reduction of multipath interference. Millimeter waves have attracted extensive attention in many 5G application fields due to their characteristics such as short wavelength, high frequency, and wide bandwidth. Planar end-fire antennas have a large application demand in fields such as handheld RFID readers, drones, and autonomous driving due to their radiation characteristics parallel to the substrate and low profile. Therefore, in recent years, millimeter-wave end-fire circularly polarized antennas have received extensive attention from scholars at home and abroad.

[0003] However, due to the disadvantages of large propagation loss and short coverage distance of millimeter waves, there is an urgent need for high-gain millimeter-wave antennas. While planar end-fire antennas usually have low gain while achieving circular polarization. Therefore, how to achieve a high-gain planar end-fire circularly polarized antenna in the millimeter-wave band is a difficult problem faced today. An existing method to improve the gain of millimeter-wave end-fire circularly polarized antennas is to introduce an additional structure. By introducing three-layer dielectric rods, the gain of the antenna is increased to 12 dBic, but the profile height of the antenna is increased. Another simpler and more direct method is widely adopted, that is, to form an antenna array. By forming an antenna array, the gain of the antenna is significantly improved, but its complex feeding network occupies a lot of space. In addition, there is also to introduce a reflective metal block on the basis of a complex and large feeding network to improve the gain of the antenna, but it further increases the overall height of the antenna.

[0004] In summary, the existing solutions to improve the gain of millimeter-wave end-fire circularly polarized antennas either introduce additional structures, or increase the profile height and the complexity of the antenna, or use a large and complex feeding network to form an antenna array, which are not conducive to the simplification, miniaturization, and integration of millimeter-wave end-fire circularly polarized antennas. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the present invention provides a broadband circularly polarized planar end-fire antenna based on substrate integrated waveguide.

[0006] In a first aspect, the present invention provides a broadband circularly polarized planar end-fire antenna based on substrate integrated waveguide, comprising a wave port, a substrate integrated waveguide, and a dipole antenna;

[0007] The substrate integrated waveguide includes a dielectric substrate, an upper metal plate, and a lower metal plate; the upper metal plate and the lower metal plate are symmetrically disposed on the upper surface and the lower surface of the dielectric substrate; two sets of metal vias are arranged side by side along the length direction of the substrate integrated waveguide on the substrate integrated waveguide; each of the metal vias penetrates and connects the upper metal plate, the dielectric substrate, and the lower metal plate;

[0008] The dipole antenna includes a first L-shaped metal sheet, a second L-shaped metal sheet, and a metal strip connecting the first L-shaped metal sheet and the second L-shaped metal sheet; the radiation edges of the first L-shaped metal sheet and the second L-shaped metal sheet point in opposite directions; one end of the first L-shaped metal sheet far from the metal strip is connected to one side of the upper metal plate along the width direction of the substrate integrated waveguide; one end of the second L-shaped metal sheet far from the metal strip is connected to one side of the lower metal plate along the width direction of the substrate integrated waveguide;

[0009] The wave port is connected to the side of the dielectric substrate far from the dipole antenna and is used to generate an excitation signal through feeding to drive the transmission of electromagnetic waves in the substrate integrated waveguide, so that the substrate integrated waveguide generates a vertically polarized electric field component and the dipole antenna generates a horizontally polarized electric field component; by adjusting the amplitude-phase relationship between the two orthogonally polarized electric field components, broadband circular polarization radiation is achieved.

[0010] Optionally, the shortest distance between the dipole antenna and the side of the dielectric substrate far from the wave port is λ / 4; λ is the wavelength of the electromagnetic wave in the substrate integrated waveguide.

[0011] Optionally, gaps are formed on the sides of the upper metal plate and the lower metal plate far from the wave port.

[0012] Optionally, the gaps on the upper metal plate and the lower metal plate are symmetrically arranged and are both V-shaped structures.

[0013] Optionally, the gaps on the upper metal plate and the lower metal plate are symmetrically arranged and are both arc-shaped structures.

[0014] Optionally, the plane where the metal strip is located is perpendicular to the plane where the first L-shaped metal sheet is located and the plane where the second L-shaped metal sheet is located.

[0015] Optionally, the relative dielectric constant of the dielectric substrate is 2.2, the loss tangent is less than 0.001, and the thickness is 1.575 mm.

[0016] Optionally, all the metal vias in each group are equally spaced; the number of metal vias in one group is the same as the number of metal vias in the other group;

[0017] The line connecting the centers of the metal vias closest to the wave port in one group of the metal vias and the centers of the metal vias closest to the wave port in the other group of the metal vias is parallel to the width direction of the dielectric substrate;

[0018] The line connecting the centers of the metal vias closest to the dipole antenna in one group of the metal vias and the centers of the metal vias closest to the dipole antenna in the other group of the metal vias is parallel to the width direction of the dielectric substrate.

[0019] Optionally, the equivalent width of the substrate integrated waveguide is calculated according to the following formula:

[0020] ;

[0021] where W EQ is the equivalent width of the substrate integrated waveguide; W SIW is the distance between the centers of the metal vias closest to the wave port in one group of the metal vias and the centers of the metal vias closest to the wave port in the other group of the metal vias; R is the diameter of any one of the metal vias in the two groups of the metal vias; D is the distance between the centers of any two adjacent metal vias in any one group of the metal vias; α is the first intermediate variable; ; β is the second intermediate variable; ; γ is the third intermediate variable; .

[0022] In a second aspect, the present invention provides a communication device, including the broadband circularly polarized planar end-fire antenna based on the substrate integrated waveguide as described in the first aspect.

[0023] The present invention provides a broadband circularly polarized planar end-fire antenna based on the substrate integrated waveguide, which does not require an additional radiation structure to compensate for the vertical polarization component, avoids the profile height increase caused by adding an additional structure, realizes a low-profile design, and makes the structure of the broadband circularly polarized planar end-fire antenna more compact; the dipole antenna is directly connected to the upper metal plate and the lower metal plate, avoiding the introduction of complex structures such as tapered bilateral coupled lines and tapered dielectric plates, as well as additional delay lines and extended dielectric substrate designs, which not only greatly reduces the overall size of the antenna, reduces the occupied space, but also simplifies the manufacturing process, reduces the production process and material costs; the slots etched on the upper metal plate and the lower metal plate can effectively increase the horizontal polarization component of the antenna, make it balance with the vertical polarization component, thereby improving the axial ratio characteristic and enhancing the circular polarization performance. At the same time, reasonably controlling the diameter, spacing of the metal vias and the width of the substrate integrated waveguide can enable the substrate integrated waveguide to transmit electromagnetic waves at the required frequency, ensuring the stability and efficiency of signal transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] To more clearly illustrate the technical solution of the present invention, the accompanying drawings required in the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0025] Figure 1 Schematic diagram of the structure of a broadband circularly polarized planar end-fire antenna based on substrate integrated waveguide provided by an embodiment of the present invention;

[0026] Figure 2 Reflection coefficient curve graph of the broadband circularly polarized planar end-fire antenna based on substrate integrated waveguide provided by an embodiment of the present invention;

[0027] Figure 3 Axial ratio curve graph of the broadband circularly polarized planar end-fire antenna based on substrate integrated waveguide provided by an embodiment of the present invention;

[0028] Figure 4 Gain curve graph of the broadband circularly polarized planar end-fire antenna based on substrate integrated waveguide provided by an embodiment of the present invention;

[0029] Figure 5 Radiation pattern in the XY plane of the broadband circularly polarized planar end-fire antenna based on substrate integrated waveguide provided by an embodiment of the present invention at 36 GHz;

[0030] Figure 6 Radiation pattern in the YZ plane of the broadband circularly polarized planar end-fire antenna based on substrate integrated waveguide provided by an embodiment of the present invention at 36 GHz;

[0031] Figure 7 Radiation pattern in the XY plane of the broadband circularly polarized planar end-fire antenna based on substrate integrated waveguide provided by an embodiment of the present invention at 44 GHz;

[0032] Figure 8 Radiation pattern in the YZ plane of the broadband circularly polarized planar end-fire antenna based on substrate integrated waveguide provided by an embodiment of the present invention at 44 GHz;

[0033] Figure 9 Radiation pattern in the XY plane of the broadband circularly polarized planar end-fire antenna based on substrate integrated waveguide provided by an embodiment of the present invention at 52 GHz;

[0034] Figure 10 Radiation pattern in the YZ plane of the broadband circularly polarized planar end-fire antenna based on substrate integrated waveguide provided by an embodiment of the present invention at 52 GHz;

[0035] Figure 11Schematic diagram of Model 1 provided by an embodiment of the present invention;

[0036] Figure 12 Schematic diagram of Model 2 provided by an embodiment of the present invention;

[0037] Figure 13 Schematic diagram of Model 3 provided by an embodiment of the present invention;

[0038] Figure 14 Reflection coefficient comparison diagram of Model 1, Model 2, and Model 3 provided by an embodiment of the present invention;

[0039] Figure 15 Axial ratio characteristic comparison diagram of Model 1, Model 2, and Model 3 provided by an embodiment of the present invention.

[0040] Among them, 1. Wave port; 2. Substrate integrated waveguide, 21. Dielectric substrate, 22. Upper metal plate, 23. Lower metal plate, 24. Metal via; 3. Dipole antenna, 31. First L-shaped metal sheet, 32. Second L-shaped metal sheet, 33. Metal strip. Detailed implementation manners

[0041] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0042] The substrate integrated waveguide (SIW) type waveguide structure combines the advantages of three-dimensional waveguide such as low loss and closed non-radiation, and the advantages of planar integration of microstrip-like transmission lines. The structure and manufacturing are simple. It is only necessary to fabricate two rows of parallel periodic metal vias on a microwave millimeter-wave dielectric substrate. The rectangular channel surrounded by the two rows of metal vias and the upper and lower metal surfaces can be equivalent to a dielectric-filled rectangular waveguide, that is, SIW. The waveguide characteristics of SIW are very similar to those of traditional rectangular waveguides. Its loss is between that of traditional metal waveguides and microstrip transmission lines. Especially in the millimeter-wave or higher frequency bands, the advantages of SIW are more obvious. Since the PCB processing technology has been very mature, it is very easy to fabricate metal vias on the dielectric substrate. Therefore, the SIW structure has the advantages of easy processing and planar integration.

[0043] Due to the above advantages of the SIW structure, various functional microwave millimeter-wave and even terahertz devices can be fabricated based on the SIW structure, such as resonators, filters, couplers, multiplexers, antennas, frequency selective surfaces, etc. These devices can be integrated into a planar system and can be conveniently co-planarly integrated with active integrated circuits (chips) and other planar transmission lines.

[0044] As shown Figure 1 in the figure, this embodiment provides a broadband circularly polarized planar end-fire antenna based on a substrate integrated waveguide, which includes a wave port 1, a substrate integrated waveguide 2, and a dipole antenna 3.

[0045] As shown Figure 11 in Figure 12 and Figure 13 the figure, the substrate integrated waveguide 2 includes a dielectric substrate 21, an upper metal plate 22, and a lower metal plate 23; the upper metal plate 22 and the lower metal plate 23 are symmetrically arranged on the upper surface and the lower surface of the dielectric substrate 21; two groups of metal vias 24 are arranged side by side along the length direction of the substrate integrated waveguide 2 on the substrate integrated waveguide 2; each metal via 24 penetrates and connects the upper metal plate 22, the dielectric substrate 21, and the lower metal plate 23.

[0046] All the metal vias 24 in each group are equally spaced; the number of metal vias 24 in one group (for example, the first group) is the same as the number of metal vias 24 in the other group (for example, the second group). In this embodiment, if the number of metal vias 24 in the first group is 10 and the spacing between any two adjacent metal vias 24 is a, then the number of metal vias 24 in the second group is also 10, and the spacing between any two adjacent metal vias 24 is also a.

[0047] The line connecting the centers of the metal vias 24 closest to the wave port 1 in one group of metal vias 24 and the centers of the metal vias 24 closest to the wave port 1 in the other group of metal vias 24 is parallel to the width direction of the dielectric substrate 21.

[0048] The line connecting the centers of the metal vias 24 closest to the dipole antenna 3 in one group of metal vias 24 and the centers of the metal vias 24 closest to the dipole antenna 3 in the other group of metal vias 24 is parallel to the width direction of the dielectric substrate 21. In this embodiment, if the two groups of metal vias 24 are sorted along the length direction of the dielectric substrate 21, then the line connecting the centers of the first metal via 24 in the first group and the centers of the first metal via 24 in the second group is parallel to the width direction of the dielectric substrate 21.

[0049] The upper and lower surfaces of the dielectric substrate 21 are short-circuited by metal vias 24 (such as vias made of copper material), which is similar to a rectangular waveguide filled with a dielectric. By reasonably controlling the diameter of the metal vias 24, the distance between the metal vias 24, and the width and height of the substrate integrated waveguide 2, the substrate integrated waveguide 2 only transmits TE 10 mode waves at the required frequency.

[0050] Due to the leakage between the metallized vias on both sides of the SIW structure, it is very important to appropriately select the via pitch. If the distance between two metal vias 24 is properly chosen, the energy inside the waveguide structure will hardly leak out. At this time, the two groups of metal vias 24 can be equivalent to two electric walls, and the upper metal plate 22 and the lower metal plate 23 can be regarded as the upper and lower waveguide walls of a rectangular waveguide. The waveguide characteristics of the SIW are very similar to those of a rectangular waveguide. The equivalent rectangular waveguide width of the SIW is also of great significance for simulation analysis in the High-Frequency Structure Simulator (HFSS). When using HFSS to determine the equivalent rectangular waveguide width of the SIW, that is, the width set at the wave port 1, only using the above method cannot ensure very high precision, and the error in setting the wave port will lead to inaccurate subsequent analysis. Therefore, it is also necessary to rely on HFSS to determine it.

[0051] Exemplarily, the equivalent width of the substrate integrated waveguide 2 is calculated according to the following formula:

[0052] 。

[0053] Where, W EQ is the equivalent width of the substrate integrated waveguide 2; W SIW is the distance between the centers of the metal vias 24 closest to the wave port 1 in one group of metal vias 24 and the centers of the metal vias 24 closest to the wave port 1 in the other group of metal vias 24; R is the diameter of any one of the metal vias 24 in the two groups of metal vias 24; D is the distance between the centers of any two adjacent metal vias 24 in any one group of metal vias 24; α is the first intermediate variable; ; β is the second intermediate variable; ; γ is the third intermediate variable; 。

[0054] In this embodiment, the material of the dielectric substrate 21 is Rogers 5880 or Taconic TLY-5, with a relative dielectric constant of 2.2, a loss tangent of 0.0009 (less than 0.001), and a thickness of 1.575 mm.

[0055] The dipole antenna 3 includes a first L-shaped metal sheet 31, a second L-shaped metal sheet 32, and a metal strip 33 connecting the first L-shaped metal sheet 31 and the second L-shaped metal sheet 32; one end of the first L-shaped metal sheet 31 far from the metal strip 33 is connected to one side of the upper metal plate 22 along the width direction of the substrate integrated waveguide 2; one end of the second L-shaped metal sheet 32 far from the metal strip 33 is connected to one side of the lower metal plate 23 along the width direction of the substrate integrated waveguide 2. In this embodiment, the plane where the metal strip 33 is located is perpendicular to the plane where the first L-shaped metal sheet 31 is located and the plane where the second L-shaped metal sheet 32 is located; the plane where the metal strip 33 is located is parallel to the width direction of the dielectric substrate 21.

[0056] The radiation edges of the first L-shaped metal sheet 31 and the second L-shaped metal sheet 32 point in opposite directions. In this embodiment, the opening formed by the first L-shaped metal sheet 31 and the upper metal plate 22 is taken as the first opening, and the opening formed by the second L-shaped metal sheet 32 and the lower metal plate 23 is taken as the second opening. If the short side of the first L-shaped metal sheet 31 is connected to the upper metal plate 22 and the short side of the second L-shaped metal sheet 32 is connected to the lower metal plate 23, then the opening directions of the first opening and the second opening are opposite.

[0057] The wave port 1 is connected to the side of the dielectric substrate 21 far from the dipole antenna 3, and is used to generate an excitation signal through feeding to drive the transmission of electromagnetic waves in the substrate integrated waveguide 2, so that the substrate integrated waveguide 2 generates a vertically polarized electric field component (i.e., the electric field component perpendicular to the upper surface of the dielectric substrate 21) and the dipole antenna 3 generates a horizontally polarized electric field component (i.e., the electric field component parallel to the width direction of the dielectric substrate 21); by adjusting the amplitude-phase relationship between the two orthogonally polarized electric field components, broadband circularly polarized radiation is realized.

[0058] In this embodiment, the size and position of the wave port 1 are configured such that only the TE 10 mode is transmitted in the substrate integrated waveguide 2 within the frequency band. The shortest distance between the dipole antenna 3 and the side of the dielectric substrate 21 far from the wave port 1 is λ / 4 to satisfy the 90° phase difference required for circular polarization and generate good circular polarization characteristics; λ is the wavelength of the electromagnetic wave in the substrate integrated waveguide 2.

[0059] Slots are opened on the sides of the upper metal plate 22 and the lower metal plate 23 far from the wave port 1 to increase the magnitude of the horizontally polarized component of the broadband circularly polarized planar end-fire antenna provided in this embodiment and balance it with the vertically polarized component, thereby improving its axial ratio characteristics. Among them, the slots on the upper metal plate 22 and the lower metal plate 23 are symmetrically arranged, and the structure of the slots includes, but is not limited to, a V-shaped structure and an arc-shaped structure, and can also be other irregular polygonal structures. Taking the V-shaped structure as an example, the capacitive reactance of the broadband circularly polarized planar end-fire antenna is too large throughout the bandwidth. Etching the V-shaped structure slot reduces the area at the opening of the substrate integrated waveguide, thereby effectively reducing its equivalent capacitance, so the impedance matching is improved.

[0060] As Figure 2 , Figure 3 and Figure 4 shown, the reflection coefficient, axial ratio and gain characteristic curves of the broadband circularly polarized planar end-fire antenna provided in this embodiment are given respectively. Taking -10 dB as the standard, the reflection coefficient bandwidth of the broadband circularly polarized planar end-fire antenna is 45.4%, covering 34 GHz to 54 GHz. As Figure 1 shown, taking the length direction of the dielectric substrate 21 as the Y-axis, the width direction of the dielectric substrate 21 as the X-axis, and the direction perpendicular to the Y-axis and X-axis as the Z-axis; in the end-fire (+Y) direction, the axial ratio bandwidth of the broadband circularly polarized planar end-fire antenna is 41.6%, covering 34.31 GHz to 52.63 GHz, and having a radiation gain of nearly 6.81 dBic - 10.43 dBic in the end-fire direction.

[0061] As Figure 5 and Figure 6 shown, the radiation patterns of the broadband circularly polarized planar end-fire antenna provided in this embodiment in the XY plane and YZ plane at 36 GHz are given respectively. As Figure 7 and Figure 8 shown, the radiation patterns of the broadband circularly polarized planar end-fire antenna provided in this embodiment in the XY plane and YZ plane at 44 GHz are given respectively. As Figure 9 and Figure 10 shown, the radiation patterns of the broadband circularly polarized planar end-fire antenna provided in this embodiment in the XY plane and YZ plane at 52 GHz are given respectively. It can be seen that the maximum gain direction of the broadband circularly polarized planar end-fire antenna provided in this embodiment always remains in the +Y direction, having stable pattern characteristics.

[0062] As Figure 11 , Figure 12 and Figure 13 shown, the evolution process of the broadband circularly polarized planar end-fire antenna provided in this embodiment is shown in sequence, namely Model 1, Model 2 and Model 3 (Model 3 is the broadband circularly polarized planar end-fire antenna based on substrate integrated waveguide provided in this embodiment). As Figure 14 and Figure 15As shown, the reflection coefficient and axial ratio performance of Model 1 are poor. The reflection coefficient is less than -10 dB within 41 GHz - 54 GHz, but the overall resonance degree is poor. Additionally, the axial ratio of Model 1 is greater than 3 dB throughout the bandwidth. After connecting the two dipoles on the upper and lower surfaces of the dielectric substrate 21 in Model 2, the resonance degree of the reflection coefficient is improved within 39 GHz - 49 GHz. However, at this time, the reactance characteristics of the broadband circularly polarized planar end-fire antenna are still strong throughout the bandwidth. Moreover, connecting the dipoles increases the horizontal polarization component at low frequencies, and the axial ratio characteristics at low frequencies are partially improved. To further broaden the operating bandwidth, in Model 3, V-shaped slot structures are etched on the upper metal plate 22 and the lower metal plate 23. From Figure 14 and Figure 15 it can be seen that the reactance characteristics of the antenna decrease throughout the frequency band, thus achieving good impedance matching and a deeper resonance degree. At the same time, the horizontal polarization components at low and high frequencies increase, and the axial ratio performance is significantly improved, showing broadband circular polarization characteristics.

[0063] In summary, this embodiment provides a broadband circularly polarized planar end-fire antenna based on substrate integrated waveguide. It does not require an additional radiation structure to compensate for the vertical polarization component, avoiding the increased profile height caused by adding additional structures, achieving a low-profile design, and making the structure of the broadband circularly polarized planar end-fire antenna more compact. The dipole antenna 3 is directly connected to the upper metal plate 22 and the lower metal plate 23, avoiding the introduction of complex structures such as tapered bilateral coupled lines and tapered dielectric plates, as well as additional delay lines and extended dielectric substrate designs. This not only significantly reduces the overall size of the antenna, reduces the occupied space, but also simplifies the manufacturing process, reduces the production process and material costs, and improves the radiation gain of the broadband circularly polarized planar end-fire antenna. The slots etched on the upper metal plate 22 and the lower metal plate 23 can effectively increase the horizontal polarization component of the antenna, making it balance with the vertical polarization component, thereby improving the axial ratio characteristics and enhancing the circular polarization performance. At the same time, by reasonably controlling the diameter, spacing of the metal vias and the width of the substrate integrated waveguide, the substrate integrated waveguide can transmit electromagnetic waves at the required frequency, ensuring the stability and efficiency of signal transmission.

[0064] Based on the broadband circularly polarized planar end-fire antenna based on substrate integrated waveguide provided in the foregoing embodiment, the embodiment of the present invention further provides a communication device, and the communication device includes the broadband circularly polarized planar end-fire antenna based on substrate integrated waveguide described in the above embodiment.

[0065] Applying the broadband circularly polarized planar end-fire antenna based on substrate integrated waveguide provided in the embodiment of the present invention to a communication device, the communication device meets the core requirements of high-frequency communication for high performance, low cost, and miniaturization, and can be widely applied.

[0066] The present invention has been described in detail above in connection with specific embodiments and exemplary examples. However, these descriptions should not be construed as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, various equivalent substitutions, modifications or improvements can be made to the technical solutions of the present invention and their implementation manners, and all of these fall within the scope of the present invention. The protection scope of the present invention shall be subject to the appended claims.

Claims

1. A broadband circularly polarized planar end-fire antenna based on substrate integrated waveguide, characterized in that It includes a wave port (1), a substrate integrated waveguide (2), and a dipole antenna (3). The substrate integrated waveguide (2) includes a dielectric substrate (21), an upper metal plate (22), and a lower metal plate (23); the upper metal plate (22) and the lower metal plate (23) are symmetrically arranged on the upper surface and the lower surface of the dielectric substrate (21); two groups of metal vias (24) are arranged side by side along the length direction of the substrate integrated waveguide (2) on the substrate integrated waveguide (2); each metal via (24) penetrates and connects the upper metal plate (22), the dielectric substrate (21), and the lower metal plate (23). The dipole antenna (3) includes a first L-shaped metal sheet (31), a second L-shaped metal sheet (32), and a metal strip (33) connecting the first L-shaped metal sheet (31) and the second L-shaped metal sheet (32); the radiation edges of the first L-shaped metal sheet (31) and the second L-shaped metal sheet (32) point in opposite directions; one end of the first L-shaped metal sheet (31) far from the metal strip (33) is connected to one side of the upper metal plate (22) along the width direction of the substrate integrated waveguide (2); one end of the second L-shaped metal sheet (32) far from the metal strip (33) is connected to one side of the lower metal plate (23) along the width direction of the substrate integrated waveguide (2); the plane where the metal strip (33) is located is perpendicular to the plane where the first L-shaped metal sheet (31) is located and the plane where the second L-shaped metal sheet (32) is located, and the plane where the metal strip (33) is located is parallel to the width direction of the dielectric substrate (21). The wave port (1) is connected to the side of the dielectric substrate (21) far from the dipole antenna (3), and is used to generate an excitation signal through feeding to drive the transmission of electromagnetic waves in the substrate integrated waveguide (2), so that the substrate integrated waveguide (2) generates a vertically polarized electric field component and the dipole antenna (3) generates a horizontally polarized electric field component; by adjusting the amplitude-phase relationship between the two orthogonal polarized electric field components, broadband circular polarization radiation is realized. The thickness of the dielectric substrate (21) is 1.575 mm, and gaps are opened on the sides of the upper metal plate (22) and the lower metal plate (23) far from the wave port (1). The gaps on the upper metal plate (22) and the lower metal plate (23) are symmetrically arranged, and the gaps are symmetrically arranged and are both V-shaped structures. Calculate the equivalent width of the substrate integrated waveguide (2) according to the following formula: Among them, W EQ is the equivalent width of the substrate integrated waveguide (2); W SIW is the distance between the centers of the metal vias (24) closest to the wave port (1) in one group of the metal vias (24) and the centers of the metal vias (24) closest to the wave port (1) in the other group of the metal vias (24); R is the diameter of any one of the metal vias (24) in the two groups of the metal vias (24); D is the distance between the centers of any two adjacent metal vias (24) in any one group of the metal vias (24); α is the first intermediate variable; β is the second intermediate variable; γ is the third intermediate variable; 2. The broadband circularly polarized planar end-fire antenna based on substrate integrated waveguide according to claim 1, wherein The shortest distance between the dipole antenna (3) and the side of the dielectric substrate (21) far from the wave port (1) is λ / 4; λ is the wavelength of the electromagnetic wave in the substrate integrated waveguide (2).

3. The broadband circularly polarized planar end-fire antenna based on substrate integrated waveguide according to claim 1, wherein The relative dielectric constant of the dielectric substrate (21) is 2.2, and the tangent of the loss angle is less than 0.

001.

4. The broadband circularly polarized planar end-fire antenna based on substrate integrated waveguide according to claim 1, wherein All the metal vias (24) in each group are equally spaced; the number of metal vias (24) in one group is the same as the number of metal vias (24) in the other group. The line connecting the centers of the metal vias (24) closest to the wave port (1) in one group of the metal vias (24) and the centers of the metal vias (24) closest to the wave port (1) in the other group of the metal vias (24) is parallel to the width direction of the dielectric substrate (21). The line connecting the centers of the metal vias (24) closest to the dipole antenna (3) in one group of the metal vias (24) and the centers of the metal vias (24) closest to the dipole antenna (3) in the other group of the metal vias (24) is parallel to the width direction of the dielectric substrate (21).

5. A communication device, characterized in that, It includes the substrate integrated waveguide-based broadband circularly polarized planar end-fire antenna according to any one of claims 1-4.

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