Leaky-wave antenna and antenna system

Abstract

The present disclosure relates to the technical field of communications, and provides a leaky-wave antenna and an antenna system. The leaky-wave antenna comprises: a first dielectric substrate, a first metal layer, a dielectric functional layer, a second metal layer, and a second dielectric substrate. The first metal layer comprises a first transmission line and first radiation units; multiple first notches distributed at intervals are provided on a side edge, parallel to a length direction, on a first plasmon section of the first transmission line; and the multiple first radiation units and the first notches are located on the same side of the first transmission line. In the embodiments of the present disclosure, on the basis of the first plasmon section comprised in the first transmission line, the confinement capability of electromagnetic signals can be enhanced, and the radiation of the electromagnetic signals can be reduced, thereby ensuring the transmission efficiency of the electromagnetic signals, and achieving compact design of leaky-wave antennas. In addition, by radiating antenna signals outward from the first radiation units, high gain of the antenna signals can be ensured while maintaining high transmission efficiency in the first transmission line.

Description

Leaky-wave antenna and antenna system

[0001] Cross-reference to related applications

[0002] The present disclosure claims priority to Chinese Patent Application No. 202411170364.4, filed on August 23, 2024, entitled “Leaky-wave antenna and antenna system”, the entire contents of which are incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present disclosure relates to the field of communication technology, and in particular, to a leaky-wave antenna and an antenna system. BACKGROUND

[0004] The propagation of electromagnetic waves in space is to use antennas as a medium, therefore, in recent years, people pay more and more attention to it. Among various antennas, leaky-wave antennas are widely used in various industries due to their advantages such as convenient feeding, short processing period, small antenna profile, etc. In the related art, leaky-wave antennas are based on microstrip lines, closed waveguides, and substrate integrated waveguides, which inevitably have problems such as high transmission loss, low gain, and low radiation efficiency.

[0005] It should be noted that the information disclosed in the above background section is only used to strengthen the understanding of the background of the present disclosure, and therefore can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0006] The purpose of the present disclosure is to provide a leaky-wave antenna and an antenna system capable of achieving high gain and high radiation efficiency.

[0007] According to one aspect of the present disclosure, a leaky-wave antenna is provided, comprising:

[0008] a first dielectric substrate;

[0009] a first metal layer located on one side of the first dielectric substrate, and comprising a first transmission line and a plurality of first radiation units, the first transmission line comprising a first plasmonic segment, the first plasmonic segment having a plurality of first notches distributed at intervals on a side edge parallel to the length direction, the plurality of first radiation units and the first notches being located on the same side of the first transmission line, and a plurality of the first radiation units being distributed at intervals along the length direction of the first transmission line;

[0010] a dielectric functional layer located on a side of the first metal layer away from the first dielectric substrate;

[0011] a second metal layer located on a side of the dielectric functional layer away from the first dielectric substrate;

[0012] A second dielectric substrate is located on a side of the second metal layer facing away from the first dielectric substrate.

[0013] According to any one of the leaky-wave antennas of the present disclosure, the second metal layer includes a second transmission line and a plurality of second radiating elements.

[0014] The second transmission line includes a second plasmonic segment, a length direction of the second plasmonic segment is parallel to a length direction of the first plasmonic segment, and the second plasmonic segment overlaps the first plasmonic segment in a thickness direction of the first dielectric substrate.

[0015] A side edge of the second plasmonic segment parallel to the length direction has a plurality of second notches distributed at intervals, the plurality of second radiating elements and the second notches are located on the same side of the second transmission line, and the plurality of second radiating elements are distributed at intervals along the length direction of the second transmission line.

[0016] According to any one of the leaky-wave antennas of the present disclosure, the first transmission line includes a first microstrip line connected at both ends of the first plasmonic segment, the second transmission line includes a second microstrip line connected at both ends of the second plasmonic segment, and a footprint of the first microstrip line on the first dielectric substrate is located within a footprint of the second microstrip line on the first dielectric substrate.

[0017] According to any one of the leaky-wave antennas of the present disclosure, an opening direction of the first notch is opposite to an opening direction of the second notch.

[0018] According to any one of the leaky-wave antennas of the present disclosure, a center frequency of operation of the first radiating element is different from a center frequency of operation of the second radiating element.

[0019] According to any one of the leaky-wave antennas of the present disclosure, the first radiating element and the second radiating element are both metal patches with slits, and a length direction of the slit on the first radiating element intersects a length direction of the slit on the second radiating element.

[0020] According to any one of the leaky-wave antennas of the present disclosure, an acute angle formed by the length direction of the slit on the first radiating element and the length direction of the slit on the second radiating element is greater than or equal to 30 degrees and less than or equal to 60 degrees.

[0021] According to any one of the leaky-wave antennas of the present disclosure, both ends of the slit on the first radiating element and the second radiating element extend to an edge of the corresponding radiating element.

[0022] According to any one of the leaky-wave antennas of the present disclosure, the first radiating element and the second radiating element have the same outer contour shape.

[0023] In some embodiments of the leaky-wave antenna according to the present disclosure, the first radiating element and the second radiating element are both metal patches with a circular outer profile or a hexagonal outer profile.

[0024] In some embodiments of the leaky-wave antenna according to the present disclosure, the first radiating element and the second radiating element are both metal patches with a rectangular outer profile and four corners each with an angle cut.

[0025] In some embodiments of the leaky-wave antenna according to the present disclosure, the plurality of first notches have equal depths along the width direction of the first transmission line.

[0026] In some embodiments of the leaky-wave antenna according to the present disclosure, the depths of the plurality of first notches along the width direction of the first transmission line vary periodically along the length direction of the first transmission line, and the first plasmonic segment has a symmetrical structure.

[0027] In some embodiments of the leaky-wave antenna according to the present disclosure, the bottom connecting line of the plurality of first notches along the length direction of the first transmission line is a sine or cosine curve.

[0028] In some embodiments of the leaky-wave antenna according to the present disclosure, the orthographic projection of the first notch on the first dielectric substrate is a rectangle or a trapezoid.

[0029] In some embodiments of the leaky-wave antenna according to the present disclosure, the orthographic projection of the first notch on the first dielectric substrate is a triangle.

[0030] According to an aspect of the present disclosure, there is provided an antenna system comprising the leaky-wave antenna according to any one of the aspects described above.

[0031] The embodiments of the present disclosure at least have the following technical effects:

[0032] In the embodiments of the present disclosure, when the electromagnetic signal is transmitted through the first transmission line included in the first metal layer, the first plasmonic segment included in the first transmission line can be used to improve the binding capacity of the electromagnetic signal on the first transmission line, reduce the radiation of the electromagnetic signal, and thus ensure the transmission efficiency of the electromagnetic signal, while facilitating the small size setting of the first transmission line, i.e., the small size setting of the leaky-wave antenna. When the electromagnetic signal is transmitted along the first transmission line, the first radiating element can be used to cause a perturbation to the first transmission line, so as to realize high-frequency resonance between the first radiating element and the first transmission line, and thus realize the outward radiation of the antenna signal by the first radiating element, so as to ensure the high gain of the antenna signal on the basis of the high transmission efficiency of the first transmission line.

[0033] It should be understood that the general description above and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0034] The accompanying drawings, which are incorporated herein and constitute part of the specification, illustrate embodiments consistent with the present disclosure and, together with the description, further serve to explain the principles of the present disclosure. It is to be understood that the drawings are only schematic, and that they do not purport to be to scale with respect to one another. The embodiments will be described with reference to the drawings in conjunction with the detailed description, which serves to explain the principles of the present disclosure.

[0035] FIG. 1 is a schematic diagram of a cross-sectional structure of a leaky-wave antenna according to an embodiment of the present disclosure.

[0036] FIG. 2 is a schematic diagram of a top view of a first metal layer according to an embodiment of the present disclosure.

[0037] FIG. 3 is a schematic diagram of a top view of another first metal layer according to an embodiment of the present disclosure.

[0038] FIG. 4 is a schematic diagram of a top view of yet another first metal layer according to an embodiment of the present disclosure.

[0039] FIG. 5 is a schematic diagram of a top view of yet another first metal layer according to an embodiment of the present disclosure.

[0040] FIG. 6 is a schematic diagram of a top view of yet another first metal layer according to an embodiment of the present disclosure.

[0041] FIG. 7 is a schematic diagram of a top view of yet another first metal layer according to an embodiment of the present disclosure.

[0042] FIG. 8 is a schematic diagram of a top view of yet another first metal layer according to an embodiment of the present disclosure.

[0043] FIG. 9 is a schematic diagram of a top view of a second metal layer according to an embodiment of the present disclosure.

[0044] FIG. 10 is a schematic diagram of a top view of a first metal layer and a second metal layer according to an embodiment of the present disclosure.

[0045] FIG. 11 is a reflection coefficient curve of a leaky-wave antenna according to an embodiment of the present disclosure.

[0046] FIG. 12 is a radiation efficiency curve of a leaky-wave antenna according to an embodiment of the present disclosure.

[0047] FIG. 13 is a far-field radiation pattern of a leaky-wave antenna corresponding to different frequencies according to an embodiment of the present disclosure.

[0048] FIG. 14 is a far-field radiation pattern of a leaky-wave antenna corresponding to different dielectric constants according to an embodiment of the present disclosure.

[0049] 10, leaky-wave antenna; 1, first dielectric substrate; 2, first metal layer; 3, dielectric functional layer; 4, second metal layer; 5, second dielectric substrate; 21, first transmission line; 22, first radiating unit; 23, first plasmonic segment; 24, first notch; 25, first microstrip line; 26, first matching segment; 27, third notch; 41, second transmission line; 42, second radiating unit; 43, second plasmonic segment; 44, second notch; 45, second microstrip line; 46, second matching segment; 47, fourth notch. DETAILED DESCRIPTION

[0050] Example embodiments now will be described more fully hereinafter with reference to the accompanying drawings. Example embodiments, however, can be implemented in many different forms and should not be construed as limited to the implementations set forth herein; rather, these implementations are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. Like reference numerals refer to like elements throughout the specification. It will be understood that, although the terms first, second, third etc. can be used herein to describe various elements / regions, these elements / regions should not be limited by these terms since such elements / regions can be labeled in another suitable manner.

[0051] Although relative terms such as "upper", "lower", etc. are used herein to describe one component's relationship to another component in the drawings, these terms are used herein for convenience only and are not to be construed as limiting the scope of example embodiments. It is to be understood that if a device is turned over, so that the upper portion is now a lower portion, and vice versa, then what is described as on "upper" part of the other part is now described as on a "lower" part of the other part. When a structure is "on" another structure, it can mean that the structure is formed integrally with the other structure or that the structure is "directly" on the other structure, or that the structure is "indirectly" on the other structure with intervening structures between them.

[0052] The terms "one", "a", "an", "the", and "at least one" are used to indicate that "one or more" of something is / are present with the understanding that the use of these terms does not limit the number of structures to a single structure unless specifically stated. The term "including" as well as other forms such as "include", "includes" means the inclusion of an element, component, etc. without the exclusion of additional elements, components, etc. The terms "first", "second", and "third" etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.

[0053] FIG. 1 illustrates a cross-sectional structure schematic diagram of a leaky-wave antenna 10 according to an embodiment of the present disclosure, and FIG. 2 illustrates a top view structure schematic diagram of a first metal layer 2 according to an embodiment of the present disclosure.

[0054] As shown in FIG. 1, the leaky-wave antenna 10 comprises a first dielectric substrate 1, a first metal layer 2, a dielectric functional layer 3, a second metal layer 4, and a second dielectric substrate 5; the first metal layer 2 is located on one side of the first dielectric substrate 1, the dielectric functional layer 3 is located on the side of the first metal layer 2 away from the first dielectric substrate 1, the second metal layer 4 is located on the side of the dielectric functional layer 3 away from the first dielectric substrate 1, and the second dielectric substrate 5 is located on the side of the second metal layer 4 away from the first dielectric substrate 1.

[0055] As shown in FIG. 2, the first metal layer 2 comprises a first transmission line 21 and a plurality of first radiation units 22; the first transmission line 21 comprises a first plasmonic segment 23, the first plasmonic segment 23 has a plurality of first notches 24 distributed at intervals on the side edge parallel to the length direction, the plurality of first radiation units 22 and the first notches 24 are located on the same side of the first transmission line 21, and the plurality of first radiation units 22 are distributed at intervals along the length direction of the first transmission line 21.

[0056] In the embodiment of the present disclosure, when the electromagnetic signal is transmitted through the first transmission line 21 included in the first metal layer 2, the first plasmonic segment 23 included in the first transmission line 21 can be used to improve the binding capacity of the electromagnetic signal on the first transmission line 21, reduce the radiation of the electromagnetic signal, and thus ensure the transmission efficiency of the electromagnetic signal, while facilitating the small size setting of the first transmission line 21, i.e., the small size setting of the leaky-wave antenna 10. When the electromagnetic signal is transmitted along the first transmission line 21, the first radiation units 22 can be used to perturb the first transmission line 21, realize high-frequency resonance between the first radiation units 22 and the first transmission line 21, and thus realize the outward radiation of the antenna signal by the first radiation units 22, so as to ensure the high gain of the antenna signal on the basis of the high transmission efficiency of the first transmission line 21.

[0057] The first dielectric substrate 1 and the second dielectric substrate 5 can be flexible substrates such as polytetrafluoroethylene glass fiber pressboard, phenolic paper laminated board, and phenolic glass cloth laminated board, or can be hard substrate materials such as quartz, high-temperature glass, and ordinary glass. A rubber frame is arranged between the first dielectric substrate 1 and the second dielectric substrate 5 to form a containing cavity for containing the dielectric functional layer 3.

[0058] The dielectric functional layer 3 changes in dielectric constant after being affected by an external electric field, so as to phase shift the electromagnetic signal transmitted on the first transmission line 21, change the phase of the electromagnetic signal, and realize the scanning performance of the leaky-wave antenna 10. For example, the material of the dielectric functional layer 3 is liquid crystal, so that the dielectric functional layer 3 is formed by liquid crystal, and the frequency scanning characteristic of the leaky-wave antenna 10 is realized. Of course, the material of the dielectric functional layer 3 can be other dielectric constant adjustable medium except liquid crystal, such as graphene and the like. Taking the material of the dielectric functional layer 3 as liquid crystal as an example, the thickness of the dielectric functional layer 3 is greater than or equal to 3 microns and less than or equal to 100 microns, so as to ensure the coupling strength of the first metal layer 2 and the second metal layer 4. In order to improve the phase modulation response rate of the dielectric functional layer 3, the material of the dielectric functional layer 3 can be set as a polymer dispersed liquid crystal.

[0059] The first metal layer 2 and the second metal layer 4 can be low-resistance and low-loss metals such as copper, gold and silver, and can be prepared by magnetron sputtering, thermal evaporation, electroplating and the like. The thicknesses of the first metal layer 2 and the second metal layer 4 are greater than the skin depth, and different preparation methods can be selected according to different thicknesses of the first metal layer 2 and the second metal layer 4. For example, the first metal layer 2 and the second metal layer 4 are both made of copper metal, and the thicknesses of the first metal layer 2 and the second metal layer 4 are greater than or equal to 0.5 microns and less than or equal to 5 microns.

[0060] In the embodiments of the present disclosure, both ends of the first transmission line 21 are connected with the external feeding end, so as to realize the transmission of the electromagnetic signal, and also to be connected with the voltage loading end, so as to load a bias voltage on the first transmission line 21, and form an external electric field affecting the dielectric constant of the dielectric functional layer 3.

[0061] In some embodiments, as shown in FIG. 2, the first transmission line 21 further includes a first microstrip line 25 connected at both ends of the first plasmonic segment 23. In this way, the first microstrip line 25 can be directly connected with the external feeding end, so as to realize the transmission of the electromagnetic signal on the first transmission line 21.

[0062] The impedance of the first microstrip line 25 can be set to 50 ohms, so as to ensure the impedance matching between the first microstrip line 25 and the feeding port.

[0063] Optionally, as shown in FIG. 2, the first transmission line 21 further includes a first matching segment 26 connected between the first plasmonic segment 23 and the two first microstrip lines 25. Of course, in addition to separately setting the first matching segment 26 between the first microstrip line 25 and the first plasmonic segment 23, the first plasmonic segment 23 itself can include the first matching segment 26 at both ends, which is not limited in the embodiments of the present disclosure.

[0064] As shown in FIG. 2, the first matching section 26 is provided with a plurality of third notches 27, and the depths of the plurality of third notches 27 in the width direction of the first transmission line 21 gradually decrease in the direction away from the first plasmonic section 23, so as to realize the conversion between the microstrip structure and the plasmonic structure through the first matching section 26 with gradually changing structure, and ensure the transmission of electromagnetic signals between the first microstrip line 25 and the first plasmonic section 23; meanwhile, the impedance matching between the first microstrip line 25 and the first plasmonic section 23 is ensured through the first matching section 26 with gradually changing structure, so as to ensure the transmission efficiency of electromagnetic signals.

[0065] In the embodiments of the present disclosure, for the plurality of first notches 24 on the first plasmonic section 23, the interval between two adjacent first notches 24 can be set according to the wavelength corresponding to the target frequency in the working frequency band of the leaky-wave antenna 10, so as to ensure the binding strength of the first plasmonic section 23 to electromagnetic signals, and ensure the electromagnetic coupling between the first plasmonic section 23 and the first radiating unit 22.

[0066] The target frequency can be any frequency in the working frequency band, and the interval between two adjacent first notches 24 is greater than or equal to 1 / 30 of the wavelength corresponding to the target frequency, and less than or equal to 1 / 20 of the wavelength corresponding to the target frequency. For example, the target frequency is the center frequency in the working frequency band, and the interval between two adjacent first notches 24 is 1 / 30, 1 / 28, 1 / 26, 1 / 24, 1 / 22, 1 / 20, etc. of the wavelength corresponding to the center frequency.

[0067] For the plurality of first notches 24 included on the first plasmonic section 23, the depths of the plurality of first notches 24 in the width direction of the first transmission line 21 can be equal as shown in FIG. 2, or the depths of the plurality of first notches 24 in the width direction of the first transmission line 21 can be unequal as shown in FIG. 3.

[0068] When the depths of the plurality of first notches 24 in the width direction of the first transmission line 21 are equal, the depth of the first notch 24 in the width direction of the first transmission line 21 can be close to 4 / 5 of the width of the first plasmonic section 23, so as to ensure the binding effect of electromagnetic signals on the first plasmonic section 23. For example, the depth of the first notch 24 is 3 / 4, 4 / 5, 5 / 6, 6 / 7, 7 / 8, 8 / 9, 9 / 10, etc. of the width of the first plasmonic section 23.

[0069] When the depths of the plurality of first notches 24 are unequal, the depths of the plurality of first notches 24 change periodically in the length direction of the first transmission line 21 as shown in FIG. 3. For example, the bottom connecting line of the plurality of first notches 24 in the length direction of the first transmission line 21 can be a zigzag broken line, or a sine or cosine curve.

[0070] In this way, the depths of the plurality of first notches 24 are periodically changed in the length direction of the first transmission line 21 to improve the binding ability of the electromagnetic signal on the first plasmonic section 23 and increase the operating bandwidth of the leaky-wave antenna 10.

[0071] In the above embodiment, the maximum depth of the plurality of first notches 24 in the width direction of the first transmission line 21 is close to 4 / 5 of the width of the first plasmonic section 23, and the minimum depth of the plurality of first notches 24 in the width direction of the first transmission line 21 is close to 1 / 10 of the width of the first plasmonic section 23, to ensure the binding effect of the electromagnetic signal on the first plasmonic section 23. For example, the maximum depth of the plurality of first notches 24 is 3 / 4, 4 / 5, 5 / 6, 6 / 7, 7 / 8, 8 / 9, 9 / 10, etc. of the width of the first plasmonic section 23, and the minimum depth of the plurality of first notches 24 is 1 / 9, 1 / 10, 1 / 11, 1 / 12, etc. of the width of the first plasmonic section 23.

[0072] In the above embodiment, the first plasmonic section 23 is a symmetric structure to simplify the connection of the two ends of the first plasmonic section 23 to the two outer feeding ends. For example, when the first transmission line 21 includes the first matching section 26, the first matching section 26 connected to the two ends of the first plasmonic section 23 can be configured to have the same structure and be symmetrically distributed along the symmetry line of the first plasmonic section 23.

[0073] In some embodiments, as shown in FIG. 2, the first notches 24 on the first plasmonic section 23 have a triangular shape in the orthogonal projection on the first dielectric substrate 1. In this way, the triangular notches on the first plasmonic section 23 ensure the strong binding ability of the first transmission line 21 to the electromagnetic signal and ensure that the leaky-wave antenna 10 has a large operating bandwidth.

[0074] Of course, the first notches 24 on the first plasmonic section 23 can be triangular, rectangular as shown in FIG. 4, trapezoidal as shown in FIG. 5, or conical as shown in FIG. 6.

[0075] Specifically, when the first notch 24 on the first plasmon segment 23 is trapezoidal, the base (i.e., the long side) of the trapezoid may be located at the edge of the first plasmon segment 23. Furthermore, when the first notch 24 on the first plasmon segment 23 is rectangular or trapezoidal, compared to a triangular notch 24, it simplifies the manufacturing process of the first plasmon segment 23 while ensuring the leaky antenna 10 has a larger operating bandwidth. When the first notch 24 on the first plasmon segment 23 is conical, compared to a triangular notch 24, it ensures the leaky antenna 10 has a larger operating bandwidth, and compared to a rectangular or trapezoidal notch 24, it improves the confinement capability of the electromagnetic signal on the first plasmon segment 23.

[0076] It should be noted that for the plurality of third gaps 27 included in the first matching segment 26 described above, the spacing between adjacent third gaps 27, the maximum and minimum depths of the plurality of third gaps 27, and the orthographic projection shape of the third gaps 27 on the first dielectric substrate 1 can all refer to the first gap 24 described above. This embodiment of the present disclosure will not elaborate on this further, as long as the depth of the plurality of third gaps 27 gradually decreases in the direction away from the first plasmon segment 23.

[0077] In this embodiment of the disclosure, the first radiating element 22 is a metal patch with gaps, so as to realize the radiation of electromagnetic signals based on the gaps on the multiple metal patches, thereby ensuring the antenna effect of the leaky wave antenna 10.

[0078] The slit in the first radiating unit 22 can be such that both ends of the slit extend to the edge of the first radiating unit 22. Alternatively, it can be a through slit where at least one end does not extend to the edge of the first radiating unit 22.

[0079] In some embodiments, as shown in Figure 2, the first radiating element 22 is a metal patch with a circular outer contour. This simplifies the manufacturing process of the first radiating element 22 while ensuring its radiation effect, which in turn ensures the antenna effect of the leaky wave antenna 10.

[0080] Of course, the outer contour of the first radiating unit 22 can be any shape other than circular. For example, as shown in Figure 7, the first radiating unit 22 is a metal patch with a hexagonal outer contour, or as shown in Figure 8, the first radiating unit 22 is a metal patch with a rectangular outer contour and missing corners at all four corners.

[0081] When the outer contour of the first radiating unit 22 is hexagonal, the radiation effect of the first radiating unit 22 can be improved compared to the case where the first radiating unit 22 is circular. When the outer contour of the first radiating unit 22 is a rectangle with a missing corner, the structure of the first radiating unit 22 can be simplified compared to the case where the first radiating unit 22 is circular or hexagonal, so as to simplify the manufacturing process of the first radiating unit 22.

[0082] In addition, the size of the first radiating unit 22, the spacing between two adjacent first radiating units 22, and the spacing between the first radiating unit 22 and the first plasmonic segment 23 can be set according to the wavelength corresponding to a target frequency in the working frequency band of the leaky-wave antenna 10, so as to ensure the electromagnetic coupling between the first plasmonic segment 23 and the first radiating unit 22.

[0083] The target frequency can be any frequency in the working frequency band, the maximum straight-line length of the first radiating unit 22 is close to 1 / 5 of the wavelength corresponding to the target frequency, the spacing between two adjacent first radiating units 22 is close to 1 / 2 of the wavelength corresponding to the target frequency, the spacing between the center point of the first radiating unit 22 and the first plasmonic segment 23 is close to 1 / 10 of the wavelength corresponding to the target frequency, and there is a gap between the first radiating unit 22 and the first plasmonic segment 23.

[0084] For example, when the outer contour of the first radiating unit 22 is circular, the target frequency is the center frequency in the working frequency band, and the diameter of the first radiating unit 22 is 1 / 6, 1 / 5, 1 / 4, etc. of the wavelength corresponding to the center frequency, the spacing between two adjacent first radiating units 22 is 1 / 3, 1 / 2, 3 / 5, etc. of the wavelength corresponding to the center frequency, the spacing between the center of the first radiating unit 22 and the first plasmonic segment 23 is 1 / 12, 1 / 11, 1 / 10, 1 / 9, etc. of the wavelength corresponding to the center frequency, and is greater than the radius of the first radiating unit 22.

[0085] In the embodiment of the present disclosure, when the first metal layer 2 includes the first transmission line 21 and the first radiating unit 22, the second metal layer 4 can be a ground metal layer, so as to facilitate adjusting the dielectric constant of the dielectric functional layer 3 through the bias voltage loaded on the second metal layer 4 and the first metal layer 2.

[0086] Of course, the second metal layer 4 can be reused for radiation of electromagnetic signals in addition to serving as a ground metal layer. In some embodiments, as shown in FIG. 9, the second metal layer 4 includes a second transmission line 41 and a plurality of second radiation units 42, the second transmission line 41 includes a second plasmonic segment 43, the length direction of the second plasmonic segment 43 is parallel to the length direction of the first plasmonic segment 23, and the second plasmonic segment 43 overlaps the first plasmonic segment 23 in the thickness direction of the first dielectric substrate 1; the side edge parallel to the length direction of the second plasmonic segment 43 has a plurality of second notches 44 distributed at intervals, the plurality of second radiation units 42 and the second notches 44 are located on the same side of the second transmission line 41, and the plurality of second radiation units 42 are distributed at intervals along the length direction of the second transmission line 41.

[0087] In this way, when the second transmission line 41 included in the second metal layer 4 is used to transmit electromagnetic signals, the binding ability of the electromagnetic signals on the first transmission line 21 and the second transmission line 41 can be improved based on the second plasmonic segment 43 included in the second transmission line 41 and the electromagnetic coupling between the first plasmonic segment 23 and the second plasmonic segment 43, the radiation of the electromagnetic signals can be reduced, the transmission efficiency of the electromagnetic signals can be ensured, and the small size of the first transmission line 21 and the second transmission line 41, i.e., the small size of the leaky-wave antenna 10, can be easily achieved. When the electromagnetic signals are transmitted along the second transmission line 41, the high-frequency resonance between the second radiation units 42 and the second transmission line 41 can be achieved by perturbing the second transmission line 41 with the second radiation units 42, and the antenna signals can be radiated outward by the second radiation units 42, so that the high gain of the antenna signals can be ensured on the basis of the high transmission efficiency of the second transmission line 41.

[0088] In the embodiments of the present disclosure, the specific configuration of the second transmission line 41 can refer to the configuration of the first transmission line 21 described in the above embodiments. For example, as shown in FIG. 9, the second transmission line 41 includes a second microstrip line 45 connected at both ends of the second plasmonic segment 43, and a second matching segment 46 connected between the second plasmonic segment 43 and the second microstrip line 45.

[0089] As shown in FIG. 9, the second matching segment 46 has a fourth notch 47, and the second notch 44 on the second plasmonic segment 43 and the fourth notch 47 on the second matching segment 46 can refer to the first notch 24 and the third notch 27 described in the above embodiments, respectively. In addition, the projection shape of the second notch 44 and the projection shape of the first notch 24, and the projection shape of the fourth notch 47 and the projection shape of the third notch 27 can be completely the same or different, and the embodiments of the present disclosure do not limit this.

[0090] Optionally, as shown in FIG. 10, the first microstrip line 25 included in the first transmission line 21 has a projection on the first dielectric substrate 1 that is located within the projection on the first dielectric substrate 1 of the second microstrip line 45 included in the second transmission line 41. In this way, when the second metal layer 4 is reused as a ground metal layer, the ground effect of the second transmission line 41 can be effectively ensured.

[0091] In the embodiments of the present disclosure, the specific arrangement of the second radiating unit 42 can refer to the arrangement of the first radiating unit 22 described in the above embodiments. For example, the second radiating unit 42 is a metal patch with a slit.

[0092] The outer contour shapes of the first radiating unit 22 and the second radiating unit 42 can be the same or different. For example, as shown in FIG. 10, the first radiating unit 22 and the second radiating unit 42 are both circular metal patches with slits. The lengths of the slits on the first radiating unit 22 and the second radiating unit 42 can be the same or different. For example, the two ends of the slit on the first radiating unit 22 and the second radiating unit 42 both extend to the edges of the corresponding radiating unit.

[0093] In addition, when the first radiating unit 22 and the second radiating unit 42 are both metal patches with slits, the length direction of the slit on the first radiating unit 22 can be arranged in parallel with the length direction of the slit on the second radiating unit 42, or as shown in FIG. 10, the length direction of the slit on the first radiating unit 22 can intersect with the length direction of the slit on the second radiating unit 42, so that the cutting electric field of the electromagnetic signals radiated by the first radiating unit 22 and the second radiating unit 42 is the strongest, thereby further ensuring the antenna effect of the leaky-wave antenna 10.

[0094] Optionally, the acute angle formed by the length direction of the slit on the first radiating unit 22 and the length direction of the slit on the second radiating unit 42 is greater than or equal to 30 degrees and less than or equal to 60 degrees. For example, the acute angle formed by the length direction of the slit on the first radiating unit 22 and the length direction of the slit on the second radiating unit 42 is 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, 60 degrees, etc.

[0095] In some embodiments, as shown in FIG. 10, the opening direction of the first notch 24 is opposite to the opening direction of the second notch 44. In this way, the position of the first radiating unit 22 relative to the first plasmonic segment 23 is different from the position of the second radiating unit 42 relative to the second plasmonic segment 43, i.e., in the width direction of the first plasmonic segment 23, the first radiating unit 22 and the second radiating unit 42 are respectively located on the two sides of the first plasmonic segment 23, so that the double-beam radiation of the leaky-wave antenna 10 can be realized through the first radiating unit 22 and the second radiating unit 42, thereby further improving the antenna effect of the leaky-wave antenna 10.

[0096] Of course, the opening direction of the first notch 24 can also be set to be the same as that of the second notch 44, in which case the first radiating unit 22 and the second radiating unit 42 are located on the same side of the first plasmonic section 23 in the width direction of the first plasmonic section 23, so that the radiation superposition of single beams can be realized by the first radiating unit 22 and the second radiating unit 42 to further improve the antenna effect of the leaky-wave antenna 10.

[0097] In some embodiments, the first radiating unit 22 and the second radiating unit 42 have different operating center frequencies, so that the scanning angles of the beams radiated by the first radiating unit 22 and the second radiating unit 42 are different, thereby improving the scanning performance of the leaky-wave antenna 10.

[0098] In the formula, for different operating center frequencies of the first radiating unit 22 and the second radiating unit 42, the first radiating unit 22 and the second radiating unit 42 can correspond to two operating frequencies within the operating frequency band of the leaky-wave antenna 10, respectively, and different structural sizes of the first radiating unit 22 and the second radiating unit 42 can be set to realize this.

[0099] For example, the structural size of the first radiating unit 22 can be set according to the minimum frequency within the operating frequency band of the leaky-wave antenna 10, and the structural size of the second radiating unit 42 can be set according to the maximum frequency within the operating frequency band of the leaky-wave antenna 10.

[0100] In some embodiments, for the first transmission line 21 and the first radiating unit 22 included in the first metal layer 2, the orthographic projections of the first notch 24 and the third notch 27 on the first dielectric substrate 1 are all triangles, the spacing between adjacent two notches is 1 / 20 of the wavelength corresponding to the minimum frequency within the operating frequency band of the leaky-wave antenna 10, the depths of the plurality of first notches 24 along the width direction of the first transmission line 21 are equal and are all 4 / 5 of the width of the first plasmonic section 23, and the depths of the plurality of third notches 27 increase from 1 / 10 of the width of the first plasmonic section 23 to 4 / 5; the first radiating unit 22 is a circular metal patch with a gap, the diameter of the first radiating unit 22 is 1 / 5 of the wavelength corresponding to the minimum frequency within the operating frequency band, the spacing between adjacent two first radiating units 22 is 1 / 2 of the wavelength corresponding to the minimum frequency within the operating frequency band, and the spacing between the center of the first radiating unit 22 and the first plasmonic section 23 is close to 1 / 10 of the wavelength corresponding to the minimum frequency within the operating frequency band and is greater than the radius of the first radiating unit 22.

[0101] For the second transmission line 41 and the second radiating unit 42 included in the second metal layer 4, the normal projections of the second notch 44 and the fourth notch 47 on the first dielectric substrate 1 are all triangles, the interval between two adjacent notches is 1 / 20 of the wavelength corresponding to the maximum frequency in the working frequency band of the leaky-wave antenna 10, the depths of the plurality of second notches 44 along the width direction of the second transmission line 41 are equal and are all 4 / 5 of the width of the second plasmonic segment 43, and the depths of the plurality of fourth notches 47 increase from 1 / 10 of the width of the second plasmonic segment 43 to 4 / 5. The second radiating unit 42 is a circular metal patch with a gap, the diameter of the second radiating unit 42 is 1 / 5 of the wavelength corresponding to the maximum frequency in the working frequency band, the interval between two adjacent second radiating units 42 is 1 / 2 of the wavelength corresponding to the maximum frequency in the working frequency band, and the interval between the center of the second radiating unit 42 and the second plasmonic segment 43 is close to 1 / 10 of the wavelength corresponding to the maximum frequency in the working frequency band and is greater than the radius of the second radiating unit 42.

[0102] In combination with the leaky-wave antenna 10 described in the above embodiments, FIG. 11 shows the reflection coefficient curves of the leaky-wave antenna 10 when the dielectric functional layer 3 corresponds to different dielectric constants, it can be seen from FIG. 11 that the reflection coefficients of the leaky-wave antenna 10 are all less than -10 dB in the working frequency band of 11 GHz-13 GHz, indicating that the leaky-wave antenna 10 has good matching characteristics in the working frequency band of 11 GHz-13 GHz. FIG. 12 shows the radiation efficiency curves of the leaky-wave antenna 10 when the dielectric functional layer 3 corresponds to different dielectric constants, it can be seen from FIG. 12 that the radiation efficiencies of the leaky-wave antenna 10 are all above 90% in the working frequency band of 11 GHz-13 GHz, indicating that the leaky-wave antenna 10 has good leaky-wave characteristics. FIG. 13 shows the far-field radiation patterns of the leaky-wave antenna 10 at three frequencies of 11 GHz, 12 GHz and 13 GHz, it can be seen from FIG. 13 that the leaky-wave antenna 10 has good directivity and frequency scanning characteristics, has a forward beam with a positive angle and a backward beam with a negative angle in the working frequency band, and the forward beam has a scanning range of about 30 degrees and the backward beam has a scanning range of about 27 degrees. FIG. 14 shows the far-field radiation patterns of the leaky-wave antenna 10 at a frequency of 12 GHz and when the dielectric functional layer 3 corresponds to different dielectric constants, it can be seen from FIG. 14 that the radiation directivity of the leaky-wave antenna 10 changes with the change of the dielectric constant, indicating that the leaky-wave antenna 10 has good frequency scanning characteristics.

[0103] In the embodiments of the present disclosure, an antenna system is provided, which includes the leaky-wave antenna 10 described in the above embodiments. In combination with the leaky-wave antenna 10 described above, the transmission efficiency of electromagnetic signals in the antenna system is ensured, and the miniaturization of the antenna system is facilitated.

[0104] Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the features disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

Claims

1. A leaky-wave antenna, wherein, The application relates to a substrate for a millimeter wave antenna, comprising: a first dielectric substrate; a first metal layer located on one side of the first dielectric substrate and comprising a first transmission line and a plurality of first radiation units, the first transmission line comprising a first plasmonic segment, a side edge of the first plasmonic segment parallel to the length direction having a plurality of first notches distributed at intervals, the plurality of first radiation units and the first notches being located on the same side of the first transmission line, and the plurality of first radiation units being distributed at intervals along the length direction of the first transmission line; a dielectric functional layer located on the side of the first metal layer away from the first dielectric substrate; a second metal layer located on the side of the dielectric functional layer away from the first dielectric substrate; a second dielectric substrate located on the side of the second metal layer away from the first dielectric substrate.

2. The leaky-wave antenna of claim 1, wherein, The second metal layer comprises a second transmission line and a plurality of second radiation units; the second transmission line comprises a second plasmonic segment, the length direction of the second plasmonic segment being parallel to the length direction of the first plasmonic segment, and the second plasmonic segment and the first plasmonic segment having an overlapping region in the thickness direction of the first dielectric substrate; a side edge of the second plasmonic segment parallel to the length direction has a plurality of second notches distributed at intervals, the plurality of second radiation units and the second notches being located on the same side of the second transmission line, and the plurality of second radiation units being distributed at intervals along the length direction of the second transmission line.

3. The leaky-wave antenna of claim 2, wherein, The first transmission line comprises a first microstrip line connected at both ends of the first plasmonic segment, the second transmission line comprises a second microstrip line connected at both ends of the second plasmonic segment, and the orthographic projection of the first microstrip line on the first dielectric substrate is located within the orthographic projection of the second microstrip line on the first dielectric substrate.

4. The leaky-wave antenna of claim 2, wherein, The opening direction of the first notches is opposite to the opening direction of the second notches.

5. The leaky-wave antenna of claim 4, wherein, The operating center frequency of the first radiation units is different from that of the second radiation units.

6. The leaky-wave antenna of claim 4, wherein, The first radiation units and the second radiation units are both metal patches with slits, and the length direction of the slits on the first radiation units intersects the length direction of the slits on the second radiation units.

7. The leaky-wave antenna of claim 6, wherein, The acute angle formed by the length direction of the slits on the first radiation units and the length direction of the slits on the second radiation units is greater than or equal to 30 degrees and less than or equal to 60 degrees.

8. The leaky-wave antenna of claim 6, wherein, Both ends of the slits on the first radiation units and the second radiation units extend to the edges of the corresponding radiation units.

9. The leaky-wave antenna of any one of claims 2-8, wherein, The first radiation units and the second radiation units have the same outer contour shape.

10. The leaky-wave antenna of claim 9, wherein, The first radiation units and the second radiation units are both metal patches with a circular outer contour or hexagonal metal patches.

11. The leaky-wave antenna of claim 9, wherein, The first radiation units and the second radiation units are both metal patches with a rectangular outer contour and notched corners.

12. The leaky-wave antenna of any one of claims 1-8, wherein, The depths of the plurality of first notches along the width direction of the first transmission line are equal.

13. The leaky-wave antenna of any one of claims 1-8, wherein, In the length direction of the first transmission line, the depths of the plurality of first notches along the width direction of the first transmission line change periodically, and the first plasmonic segment is a symmetrical structure.

14. The leaky-wave antenna of claim 13, wherein, In a length direction of the first transmission line, the bottom lines of the plurality of first notches are sinusoidal or cosinusoidal curves.

15. The leaky-wave antenna of any one of claims 1-8, wherein, A normal projection of the first notches on the first dielectric substrate is a rectangle or a trapezoid.

16. The leaky-wave antenna of any one of claims 1-8, wherein, A normal projection of the first notches on the first dielectric substrate is a triangle.

17. An antenna system, wherein, The leaky-wave antenna of any one of claims 1-16.

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