A leaky-wave antenna based on a circularly symmetric split ring

Abstract

The present invention discloses a leaky-wave antenna based on circularly symmetric split-ring resonators, which relates to the technical field of antenna beam scanning. The leaky-wave antenna includes a plurality of antenna units arranged in an array. Each antenna unit includes: a first metal layer, which includes a first resonant structure and a second resonant structure, and both the first resonant structure and the second resonant structure are hollow structures; a second metal layer, which includes a third resonant structure and a fourth resonant structure, and both the third resonant structure and the fourth resonant structure are hollow structures; the third resonant structure is rotationally symmetric with the first resonant structure, and the fourth resonant structure is rotationally symmetric with the second resonant structure; a dielectric layer, which is located between the first metal layer and the second metal layer, and the dielectric layer includes two rows of metallized vias arranged oppositely, and the metallized vias are used to connect the first metal layer and the second metal layer to form a substrate integrated waveguide structure. The present invention can realize a high-efficiency leaky-wave antenna.

Description

Technical Field

[0001] The present invention belongs to the technical field of antenna beam scanning, and particularly relates to a leaky-wave antenna based on a circularly symmetric split ring. Background Art

[0002] A leaky-wave antenna (LWA) is an antenna that forms radiation by continuously or periodically loading radiation elements on the main transmission line structure, so that the electromagnetic energy carried by the main transmission line continuously leaks into free space. The physical structure of the leaky-wave antenna integrates the feeding / phase-shifting network and the radiation unit, making the structure of the leaky-wave antenna more compact; compared with a phased array antenna, the leaky-wave antenna does not require any external T / R components and has the characteristics of small volume and light weight. With its unique narrow-beam radiation characteristics and beam scanning ability, the leaky-wave antenna has broad application prospects in the fields of microwave imaging, target detection and tracking, and high-precision point-to-point communication. Currently, the leaky-wave antenna is developing towards single-sided scanning to double-sided scanning, high efficiency, and beam scanning continuity.

[0003] Currently, for a frequency-scanned leaky-wave antenna, by adjusting the distance between two structurally similar but different radiation elements, the antenna beam maintains a stable gain characteristic when scanned to the broadside direction, eliminating the influence of the open stopband effect of the periodic leaky-wave antenna. At the same time, the sensitive dispersion-frequency response generated by a high-dielectric-constant medium is also utilized to achieve large-angle continuous beam scanning; however, there are still the following deficiencies: (1) The beam scanning angle of the frequency-scanned antenna cannot achieve 360-degree full-space scanning, and the radiation efficiency is relatively low; (2) The radiation pattern is relatively single, and most of the existing frequency-scanned leaky-wave antennas cannot achieve the end-fire radiation state. However, the existing fixed-beam radiation leaky-wave antennas do not have the frequency scanning function; (3) Reports on leaky-wave antennas with full-space frequency scanning characteristics are relatively rare, especially there is no substrate-integrated waveguide type leaky-wave antenna with full-space scanning so far.

[0004] Therefore, it is urgent to improve the above deficiencies existing in the prior art. Summary of the Invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a leaky-wave antenna based on a circularly symmetric split ring. The technical problems to be solved by the present invention are realized through the following technical solutions:

[0006] In a first aspect, the present invention provides a leaky-wave antenna based on a circularly symmetric split ring, including a plurality of antenna units arranged in an array, and the antenna unit includes:

[0007] The first metal layer, the first metal layer includes a first resonant structure and a second resonant structure, both the first resonant structure and the second resonant structure are hollow structures; the first resonant structure and the second resonant structure are used to extend the current path;

[0008] The second metal layer, the second metal layer includes a third resonant structure and a fourth resonant structure, both the third resonant structure and the fourth resonant structure are hollow structures; the third resonant structure and the fourth resonant structure are used to extend the current path, the third resonant structure is rotationally symmetric with the first resonant structure, and the fourth resonant structure is rotationally symmetric with the second resonant structure;

[0009] The dielectric layer, located between the first metal layer and the second metal layer, the dielectric layer includes two rows of metallized vias arranged oppositely, and the metallized vias are used to connect the first metal layer and the second metal layer to form a substrate integrated waveguide structure.

[0010] Advantages of the present invention:

[0011] (1) A leaky wave antenna based on a circularly symmetric split ring provided by the present invention extends the effective path of the current, increases the effective resonance length, that is, introduces a larger phase difference per unit length, greatly improves the dispersion sensitivity, enables the antenna to achieve an increase in the scanning angle and a narrower frequency band occupied by the beam full-space scanning.

[0012] (2) A leaky wave antenna based on a circularly symmetric split ring provided by the present invention has a stronger current cutting ability, resulting in a larger attenuation constant, that is, more energy leakage per unit length, finally forming effective antenna radiation, thereby realizing the miniaturization of the antenna, and at the same time, the larger attenuation constant makes the antenna radiate more energy.

[0013] (3) A leaky wave antenna based on a circularly symmetric split ring provided by the present invention realizes the change of the phase constant β from -k0 ≤ β ≤ k0, the end radio frequency point is far from the stop band, meeting the necessary conditions for beam full-space scanning. Compared with the existing substrate integrated waveguide leaky wave antenna, it realizes the full-space scanning leaky wave antenna based on the substrate integrated waveguide for the first time.

[0014] (4) A leaky wave antenna based on a circularly symmetric split ring provided by the present invention realizes the integration of the end-fixed beam radiation mode and the frequency scanning mode, expanding the functions of the substrate integrated waveguide leaky wave antenna.

[0015] (5) A leaky wave antenna based on a circularly symmetric split ring provided by the present invention realizes the radiation characteristics of dual beams, bringing full-space radiation and achieving a wider airspace coverage range.

[0016] The present invention will be further described in detail below with reference to the drawings and embodiments. Description of the Drawings

[0017] Figure 1 It is a top view of a leaky-wave antenna unit provided by an embodiment of the present invention;

[0018] Figure 2 It is a schematic structural diagram of a leaky-wave antenna unit provided by an embodiment of the present invention;

[0019] Figure 3 It is a schematic diagram of the current in a leaky-wave antenna unit provided by an embodiment of the present invention;

[0020] Figure 4 It is a schematic structural diagram of a leaky-wave antenna provided by an embodiment of the present invention;

[0021] Figure 5(a) is a schematic diagram showing the variation of the phase constant with frequency provided by an embodiment of the present invention;

[0022] Figure 5(b) is a schematic diagram showing the variation of the attenuation constant with frequency provided by an embodiment of the present invention;

[0023] Figure 6 It is a schematic diagram of an S-parameter curve provided by an embodiment of the present invention;

[0024] Figure 7(a) is the radiation pattern of a leaky-wave antenna provided by an embodiment of the present invention;

[0025] Figure 7(b) is a schematic diagram showing the achievable gain and radiation efficiency provided by an embodiment of the present invention. Detailed implementation manners

[0026] The following further describes the present invention in detail with reference to specific embodiments, but the implementation manners of the present invention are not limited thereto.

[0027] In the prior art, for a substrate integrated waveguide (SIW) type leaky-wave antenna, the following main deficiencies exist: (1) The beam scanning angle of a frequency scanning antenna cannot achieve a full 180-degree spatial scan, and the radiation efficiency is relatively low; (2) The radiation pattern is relatively single, and most of the existing frequency scanning leaky-wave antennas cannot achieve an end-fire radiation state. However, the existing fixed-beam radiation leaky-wave antennas do not have a frequency scanning function; (3) Reports on leaky-wave antennas with full spatial frequency scanning characteristics are relatively rare, especially there is no SIW type leaky-wave antenna with full spatial scanning so far.

[0028] In view of this, aiming at the deficiencies of frequency scanning antennas in the prior art, especially frequency scanning leaky-wave antennas based on the SIW type, the present invention provides a leaky-wave antenna based on a circularly symmetric split ring, which has the characteristics of full spatial scan, dual-beam radiation, both frequency scanning and end-fire scanning modes, and high radiation efficiency.

[0029] Please refer to Figure 1 and Figure 2 as shown in Figure 1 which is a top view of a leaky wave antenna unit provided by an embodiment of the present invention, Figure 2 and which is a schematic structural diagram of a leaky wave antenna unit provided by an embodiment of the present invention. A leaky wave antenna based on a circular symmetric split ring provided by the present invention includes a plurality of antenna units arranged in an array. The antenna unit includes:

[0030] A first metal layer 10, the first metal layer 10 includes a first resonant structure and a second resonant structure, and the first resonant structure and the second resonant structure expose the first metal layer 10; the first resonant structure and the second resonant structure are used to extend the current path;

[0031] A second metal layer 30, the second metal layer 30 includes a third resonant structure and a fourth resonant structure, and the third resonant structure and the fourth resonant structure expose the second metal layer 30; the third resonant structure and the fourth resonant structure are used to extend the current path, the third resonant structure is rotationally symmetric with the first resonant structure, and the fourth resonant structure is rotationally symmetric with the second resonant structure;

[0032] A dielectric layer 20, located between the first metal layer 10 and the second metal layer 30, the dielectric layer 20 includes two rows of metallized vias 21 arranged oppositely, and the metallized vias 21 are used to connect the first metal layer 10 and the second metal layer 30 to form a substrate integrated waveguide structure.

[0033] Specifically, please continue to refer to Figure 1 and Figure 2 as shown in. A leaky wave antenna based on a circular symmetric split ring provided by the present invention includes a first metal layer 10, a dielectric layer 20, and a second metal layer 30 which are stacked in sequence. Among them, the first metal layer 10 and the second metal layer 30 have the same structure. The first metal layer 10 is provided with a first resonant structure and a second resonant structure. Both the first resonant structure and the second resonant structure are hollow structures, and the first resonant structure and the second resonant structure expose the dielectric layer 20. The second metal layer 30 is provided with a third resonant structure and a fourth resonant structure. Both the third resonant structure and the fourth resonant structure are hollow structures, and the third resonant structure and the fourth resonant structure expose the dielectric layer 20. The first resonant layer is rotationally symmetric with the third resonant layer, and the second resonant layer is rotationally symmetric with the fourth resonant layer; the dielectric layer 20 includes two rows of metallized vias 21 arranged oppositely, and the two rows of metallized vias 21 are respectively located on both sides of the dielectric layer 20 along a first direction. The metallized vias 21 are used for conduction, and the metallized vias 21 connect the first metal layer 10 and the second metal layer 30 to form a substrate integrated waveguide structure; in this embodiment, please refer to Figure 3 as shown, Figure 3This is a schematic diagram of the current in the leaky-wave antenna unit provided by the embodiment of the present invention. By arranging the first resonant structure and the second resonant structure in the first metal layer 10, the effective path of the current can be extended. The longer the effective current path length is, the longer the effective resonant length of the leaky-wave antenna is, which makes the phase constant change more violently within the same frequency bandwidth. Further, the phase difference caused per unit length of the antenna unit is larger, greatly improving the dispersion sensitivity, thereby increasing the scanning angle of the leaky-wave antenna and making the frequency band occupied by the full-space scanning of the beam narrower. By arranging the first resonant structure and the second resonant structure in the first metal layer 10 and the third resonant structure and the fourth resonant structure in the second metal layer 30, the radiation characteristics of dual beams are realized, bringing full-space radiation and achieving a wider airspace coverage range.

[0034] It should be noted that Figure 1 The illustrated embodiment only schematically shows a positional schematic diagram of the first metal layer 10, the dielectric layer 20, and the second metal layer 30, and does not represent the actual size; Figure 2 The illustrated embodiment only schematically shows a schematic diagram of the resonant structures in the first metal layer 10 and the second metal layer 30, and does not represent the actual size; Figure 2 The illustrated embodiment only schematically shows a structural schematic diagram of two rows of metallized vias 21 in the dielectric layer 20, and does not represent its actual size; Figure 3 The illustrated embodiment only schematically shows a path schematic diagram of the current, and does not represent the actual situation.

[0035] In an optional embodiment of the present invention, please continue to refer to Figures 1 to 3 As shown, the projection of the first resonant structure on the first metal layer 10 is rectangular, the projection of the second resonant structure on the first metal layer 10 is circular, and the first resonant structure and the second resonant structure are connected through a channel.

[0036] Specifically, please continue to refer to Figures 1 to 3 As shown, in this embodiment, the projection of the first resonant structure on the first metal layer 10 is rectangular, the projection of the second resonant structure on the first metal layer 10 is circular and includes two circles symmetric along the first resonant structure. The two circular patterns included in the second resonant structure are connected to the first resonant structure through a channel. Both the first resonant structure and the second resonant structure penetrate the first metal layer 10 along the direction perpendicular to the thickness of the first metal layer 10. Please continue to refer to Figure 3As shown, the effective path of the current with the first resonant structure and the second resonant structure is longer than that without the resonant structure, which can increase the effective resonant length more. The longer the effective current path length, the longer the effective resonant length of the leaky-wave antenna, making the phase constant change more violently within the same frequency bandwidth. Further, the phase difference caused per unit length of the antenna element is larger, greatly improving the dispersion sensitivity, thereby increasing the scanning angle of the leaky-wave antenna and making the frequency band occupied by the full-space scanning of the beam narrower. On the other hand, setting the first resonant structure as a rectangle and the second resonant structure as a circle makes the phase constant change more violently within the same bandwidth, with a stronger ability to cut the current and a larger attenuation constant, that is, more energy leakage per unit length, ultimately forming effective antenna radiation and realizing the miniaturization of the antenna. At the same time, the larger attenuation constant results in more radiation energy of the antenna.

[0037] In an alternative embodiment of the present invention, please continue to refer to Figure 1 and Figure 2 As shown, the dimension of the first resonant structure along the first direction is 3.5 mm to 4.5 mm, the dimension of the first resonant structure along the second direction is 0.2 mm to 0.3 mm, and the dimension of the first resonant structure along the third direction is 0.03 mm to 0.05 mm; wherein, the first direction intersects with the second direction and the third direction.

[0038] Specifically, please continue to refer to Figure 1 and Figure 2 As shown, in this embodiment, the dimension l s of the first resonant structure along the first direction is 4 mm, the dimension w s of the first resonant structure along the second direction is 0.25 mm, and the dimension g s of the first resonant structure along the third direction is 0.04 mm.

[0039] In an alternative embodiment of the present invention, please continue to refer to Figure 1 and Figure 2 As shown, the diameter of the circular projection of the second resonant structure on the first metal layer 10 is 1 mm to 1.5 mm, the dimension of the channel along the first direction is 0.08 mm to 0.12 mm, and the perpendicular distance between the center point of the rectangular projection of the first resonant structure on the first metal layer 10 and the channel is 0.3 mm to 0.7 mm.

[0040] Specifically, please continue to refer to Figure 1 and Figure 2 As shown, in this embodiment, the diameter D of the circular projection of the second resonant structure on the first metal layer 10 is 1.2 mm, the dimension g of the channel along the first direction is 0.1 mm, and the perpendicular distance d xIs 0.5 mm.

[0041] In an alternative embodiment of the present invention, please continue to refer to Figure 1 And Figure 2 As shown, the size of the antenna unit in the first direction is 5 mm to 9 mm, and the size of the antenna unit in the second direction is 3.5 mm to 5.5 mm.

[0042] Specifically, please continue to refer to Figure 1 And Figure 2 As shown, in this embodiment, the size w sub Of the antenna unit in the first direction is 7 mm, and the size p of the antenna unit in the second direction is 4.5 mm.

[0043] In an alternative embodiment of the present invention, please continue to refer to Figure 1 And Figure 2 As shown, the diameter of the metallized via 21 is 0.4 mm to 0.8 mm, and the distance between the midpoint of the adjacent metallized vias 21 is 0.3 mm to 0.7 mm.

[0044] Specifically, please continue to refer to Figure 1 And Figure 2 As shown, in this embodiment, the diameter d of the metallized via 21 is 0.6 mm, and the distance s between the midpoint of the adjacent metallized vias 21 is 0.5 mm.

[0045] In an alternative embodiment of the present invention, please continue to refer to Figure 1 And Figure 2 As shown, the rotational symmetry angle between the first resonant structure and the third resonant structure is 180°, and the rotational symmetry angle between the second resonant structure and the fourth resonant structure is 180°.

[0046] In an alternative embodiment of the present invention, please refer to Figure 4 As shown, Figure 4 Is a schematic structural diagram of a leaky wave antenna provided by an embodiment of the present invention, and further includes: a conversion structure located on both sides of the antenna units arranged in an array, the conversion structure is fixedly connected to the first metal layer 10, and the conversion structure is used to convert a microstrip transmission line into a substrate integrated waveguide transmission line.

[0047] In an alternative embodiment of the present invention, please continue to refer to Figure 4As shown in the figure, the conversion structure includes a first branch and a second branch that are fixedly connected. The second branch is located between the first branch and the first metal layer 10. The dimension of the second branch gradually changes along the third direction, gradually increasing from the direction pointing from the first branch to the second branch. The dimension of the first branch along the third direction is 1.3 mm to 1.7 mm, the dimension of the first branch along the second direction is 2 mm to 4 mm, the dimension of the side of the second branch close to the first metal layer 10 along the third direction is 1.8 mm to 2.2 mm, and the dimension of the second branch along the second direction is 3 mm to 5 mm.

[0048] Specifically, please continue to refer to Figure 4 As shown in the figure, in this embodiment, the dimension w1 of the first branch along the third direction is 1.5 mm, the dimension l1 of the first branch along the second direction is 3 mm, the dimension w2 of the side of the second branch close to the first metal layer 10 along the third direction is 1.8 mm to 2.2 mm, and the dimension l2 of the second branch along the second direction is 3 mm to 5 mm.

[0049] It should be noted that the overall length L of the antenna is 104 mm, which is 8.67λ0, where λ0 is the wavelength corresponding to the center frequency of the antenna. To facilitate the feeding of the antenna, the width of the antenna is adjusted, and the width W of the antenna is 14 mm.

[0050] In an alternative embodiment of the present invention, please continue to refer to Figure 2 As shown in the figure, the dimension of the dielectric layer 20 along the third direction is 0.4 mm to 0.6 mm, and the dielectric constant of the dielectric layer 20 is 2.2.

[0051] Specifically, please continue to refer to Figure 2 As shown in the figure, in this embodiment, the dimension h of the dielectric layer 20 along the third direction is 0.508 mm, and the dielectric constant of the dielectric layer 20 is 2.2.

[0052] In an alternative embodiment of the present invention, a dispersion simulation is performed on the antenna unit provided in the above embodiment to explore the variation of the phase constant and attenuation constant of the antenna unit with frequency. Please refer to Figures 5(a) to 5(b) As shown in the figure, Fig. 5(a) is a schematic diagram of the variation of the phase constant with frequency provided by the embodiment of the present invention, and Fig. 5(b) is a schematic diagram of the variation of the attenuation constant with frequency provided by the embodiment of the present invention. As can be seen from Fig. 5(a), the antenna unit realizes the variation of the phase constant β from -k0 ≤ β ≤ k0 in the range of 21.2 GHz to 29.8 GHz, and the end radio frequency point is far from the stop band, meeting the necessary conditions for full-space scanning of the beam. Compared with the existing substrate integrated waveguide leaky wave antenna, the full-space scanning leaky wave antenna based on the substrate integrated waveguide is realized for the first time. As can be seen from Fig. 5(b), the attenuation constant α of the antenna unit varies smoothly within the working frequency band in the range of 21.2 GHz to 29.8 GHz.

[0053] It should be noted that the phase constant β is a physical quantity that describes the phase change of the electromagnetic wave propagating on the transmission line during propagation. If full-space scanning is achieved, the phase constant β changes from -k0 ≤ β ≤ k0.

[0054] In an alternative embodiment of the present invention, S-parameter simulation is performed on the leaky-wave antenna provided in the above embodiment to obtain an S-parameter curve. Please refer to Figure 6 as shown Figure 6 which is a schematic diagram of the S-parameter curve provided by the embodiment of the present invention. It can be seen from Figure 6 the figure that the leaky-wave antenna has S 11 <-10 dB within the entire operating frequency band of 21.4 GHz to 29.6 GHz, achieving good matching; due to the end-fire stopband effect, the reflection coefficient of the leaky-wave antenna has a slight increase near 24.2 GHz.

[0055] In an alternative embodiment of the present invention, radiation characteristic simulation is performed on the leaky-wave antenna provided in the above embodiment to obtain a radiation pattern and simulation curves of achievable gain and efficiency. Please refer to Figures 7(a) to 7(b) as shown. Fig. 7(a) is the radiation pattern of the leaky-wave antenna provided by the embodiment of the present invention, and Fig. 7(b) is a schematic diagram of the achievable gain and radiation efficiency provided by the embodiment of the present invention. As shown in Fig. 7(a), the leaky-wave antenna can achieve full-space scanning characteristics of -90° to +90° within the entire operating frequency band of 21.6 GHz to 29.4 GHz. The sidelobes at each frequency point are small, and the front-to-back ratio of the end-fire frequency points is less than 15 dB, realizing the integration of the end-fire fixed-beam radiation mode and the frequency scanning mode, and expanding the functions of the substrate integrated waveguide leaky-wave antenna; as shown in Fig. 7(b), the variation range of the radiation efficiency of the leaky-wave antenna is 61% to 92%, and the average value is 85%; from the perspective of antenna gain, the gain of the rear end-fire frequency points is relatively high, which is because the two beams are combined into a single beam, and the directivity is significantly improved, combined with a relatively high radiation efficiency to form a high-gain characteristic. As the frequency increases, the single beam splits into two beams, and the gain decreases. When the frequency rises to the front end-fire frequency point, due to the low radiation efficiency and the fact that the antenna length is smaller than the calculated effective radiation length, the antenna radiation aperture is limited, combined with a poor reflection coefficient, resulting in a decrease in gain, but it can still achieve a fluctuation range of 8.5 dBi to 12.4 dBi, indicating that the antenna has the ability of full-space scanning with stable gain characteristics.

[0056] It should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant are intended to cover non-exclusive inclusion, so that an article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed. Without further limitation, an element defined by the statement "comprising one..." does not exclude the presence of additional identical elements in the article or device comprising the said element. Words such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The orientation or positional relationship indicated by "upper", "lower", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation on the present invention.

[0057] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification.

[0058] The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several simple deductions or substitutions can still be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. A leaky wave antenna based on a circularly symmetric split ring, characterized in that, It includes multiple antenna units arranged in an array, and the antenna unit includes: A first metal layer. The first metal includes a first resonant structure and a second resonant structure, and both the first resonant structure and the second resonant structure are hollow structures. The projection of the first resonant structure on the first metal layer is rectangular, the projection of the second resonant structure on the first metal layer is circular, and it includes two circles symmetric along the first resonant structure. The two circles included in the second resonant structure are connected to the first resonant structure through a channel. The first resonant structure and the second resonant structure are used to extend the current path. A second metal layer. The second metal layer includes a third resonant structure and a fourth resonant structure, and both the third resonant structure and the fourth resonant structure are hollow structures. The rotation symmetry angle between the first resonant structure and the third resonant structure is 180°, and the rotation symmetry angle between the second resonant structure and the fourth resonant structure is 180°. The third resonant structure and the fourth resonant structure are used to extend the current path. The third resonant structure is rotationally symmetric with the first resonant structure, and the fourth resonant structure is rotationally symmetric with the second resonant structure. A dielectric layer, located between the first metal layer and the second metal layer. The dielectric layer includes two rows of metallized vias arranged oppositely. The metallized vias are used to connect the first metal layer and the second metal layer to form a substrate integrated waveguide structure.

2. The leaky wave antenna based on a circularly symmetric split ring according to claim 1, wherein The size of the first resonant structure along the first direction is 3.5 mm to 4.5 mm, the size of the first resonant structure along the second direction is 0.2 mm to 0.3 mm, and the size of the first resonant structure along the third direction is 0.03 mm to 0.05 mm. Among them, the first direction, the second direction, and the third direction intersect each other.

3. The leaky wave antenna based on a circularly symmetric split ring according to claim 1, wherein The diameter of the circular projection of the second resonant structure on the first metal layer is 1 mm to 1.5 mm, the size of the channel along the first direction is 0.08 mm to 0.12 mm, and the vertical distance from the center point of the rectangular projection of the first resonant structure on the first metal layer to the channel is 0.3 mm to 0.7 mm.

4. The leaky wave antenna based on the circularly symmetric split ring according to claim 1, wherein The size of the antenna unit along the first direction is 5 mm to 9 mm, and the size of the antenna unit along the second direction is 3.5 mm to 5.5 mm.

5. The leaky wave antenna based on a circularly symmetric split ring according to claim 1, wherein, The diameter of the metallized via is 0.4 mm to 0.8 mm, and the distance between the midpoint of adjacent metallized vias is 0.3 mm to 0.7 mm.

6. The leaky wave antenna based on a circularly symmetric split ring according to claim 1, wherein It further includes: A conversion structure, located on both sides of the antenna units arranged in an array. The conversion structure is fixedly connected to the first metal layer, and the conversion structure is used to convert a microstrip transmission line into a substrate integrated waveguide transmission line.

7. The leaky wave antenna based on the circularly symmetric split ring according to claim 6, wherein The conversion structure includes a first branch and a second branch that are fixedly connected, and the second branch is located between the first branch and the first metal layer; the size of the second branch gradually changes in the third direction and gradually increases from the direction pointing from the first branch to the second branch; the size of the first branch in the third direction is 1.3 mm to 1.7 mm, the size of the first branch in the second direction is 2 mm to 4 mm, the size of the side of the second branch close to the first metal layer in the third direction is 1.8 mm to 2.2 mm, and the size of the second branch in the second direction is 3 mm to 5 mm.

8. The leaky wave antenna based on a circularly symmetric split ring according to claim 1, wherein The size of the dielectric layer in the third direction is 0.4 mm to 0.6 mm, and the dielectric constant of the dielectric layer is 2.2.

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