Bull-eye antenna unit, array and super-lens structure

Abstract

The invention relates to the technical field of antenna design, in particular to a bull-eye antenna unit, an array and a super-lens structure. The bullseye antenna unit adopts a standard waveguide for feeding and comprises a radiation slot and at least two concentric rings; the radiation slot is arranged at one side of the bullseye antenna unit, the feed port of the standard waveguide penetrates through the bullseye antenna unit from the other side of the bullseye antenna unit and is connected with the radiation slot, the feed port of the standard waveguide and the radiation slot adopt a gradual change design, and each concentric ring is arranged around the radiation slot as the center. The concentric rings are provided with different radiuses; the radiation slot generates directional radiation based on feeding of the standard waveguide and electromagnetic resonance generated by the concentric rings. The gradient design is adopted between the radiation slot of the bull-eye antenna unit and the standard waveguide feed port, and impedance matching is optimized, so that the antenna keeps good performance in a broadband range, the structural design profile is low, and the antenna is adaptive to lightweight and integrated deployment scenes.

Description

Technical Field

[0001] This invention relates to the field of antenna design technology, and in particular to a bullseye antenna element, array, and superlens structure. Background Technology

[0002] Currently, terahertz wireless communication mostly employs large-aperture, high-gain antennas such as horn antennas or reflector antennas to compensate for path loss of terahertz waves in space. However, these two types of antennas typically have a large profile thickness. For horn antennas to achieve high gain, the ratio of profile thickness to aperture area must satisfy a certain relationship, and the profile thickness of reflector antennas is related to the focal length. These two types of high-gain antennas are difficult to deploy in a lightweight manner.

[0003] Bullseye antennas, as a type of antenna that enhances radiation directivity through periodic structural resonance, are characterized by their simple structure, low profile, and ease of integration. The gain of a bullseye antenna is related to the number of concentric rings (aperture area). However, traditional bullseye antennas suffer from poor impedance matching between the feed structure and the radiating slot, resulting in limited operating bandwidth, making it difficult to meet broadband communication requirements and hindering their formation into antenna arrays.

[0004] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The main objective of this invention is to provide a bullseye antenna element, array, and superlens structure, aiming to solve the technical problem that the narrow operating bandwidth of bullseye antennas makes it difficult to form an antenna array in the prior art.

[0006] In a first aspect, the present invention provides a bullseye antenna element, wherein the bullseye antenna element is fed by a standard waveguide and the bullseye antenna element includes: a radiating slot and at least two concentric rings; The radiating slot is located on one side of the bullseye antenna unit. The feed port of the standard waveguide penetrates the bullseye antenna unit from the other side and connects to the radiating slot. The feed port of the standard waveguide and the radiating slot adopt a gradient design. Each concentric ring is arranged around the radiating slot as the center, and each concentric ring is provided with a different radius. The radiating slot generates directional radiation based on the feeding of the standard waveguide and the electromagnetic resonance generated by each of the concentric rings.

[0007] Optionally, the thickness of the bullseye antenna element, the length of the radiating slot, the width of the radiating slot, the slot width of the concentric ring, and the width of the concentric ring are all set based on the center frequency of the antenna operation.

[0008] In a second aspect, the present invention provides a bullseye antenna array, the bullseye antenna array comprising: at least two bullseye antenna elements as described above; The bullseye antenna elements are arranged in an array; Each of the bullseye antenna elements includes the same number of concentric rings. The concentric rings with the same number in adjacent bullseye antenna elements intersect and merge, and the merged concentric ring does not intersect or overlap with concentric rings with a number lower than that number.

[0009] Optionally, in the bullseye antenna array, the center-to-center spacing of the radiating slots of two adjacent bullseye antenna elements along the first direction and the center-to-center spacing of the radiating slots of two adjacent bullseye antenna elements along the second direction are both set according to the center frequency of the antenna operation, and the first direction and the second direction are perpendicular to each other.

[0010] Thirdly, the present invention provides a superlens structure, the superlens structure comprising: a superlens array and a bullseye antenna array as described above; The superlens array is mounted on the bullseye antenna array and connected by mechanical alignment and direct fixation.

[0011] Optionally, the superlens array includes: a plurality of superlens units; Each of the superlens units is uniformly distributed based on multiple angular intervals of the superlens array, and the phase modulation range of the superlens units with different angular intervals is different.

[0012] Optionally, the superlens unit includes: an upper structure and a lower structure; The center lines of the upper structure and the lower structure coincide; The upper structure is configured as a frustum-shaped column, and the lower structure is configured as a cuboid with an inwardly tapered frustum-shaped column. The frustum-shaped column of the upper structure and the inwardly tapered frustum-shaped column of the lower structure have a gradually decreasing radius along the height direction of the column cross-section.

[0013] Optionally, the width of the upper surface of the upper half structure, the width of the lower surface of the upper half structure, and the height of the upper half structure are set based on the center frequency of the antenna operation.

[0014] Optionally, the width of the upper surface of the inner truncated pyramidal column in the lower half structure is the same as the width of the upper surface of the upper half structure, the width of the lower surface of the inner truncated pyramidal column in the lower half structure is the same as the width of the lower surface of the upper half structure, and the height of the inner truncated pyramidal column in the lower half structure is set based on the center frequency of the antenna operation.

[0015] Optionally, the hypotenuse of the frustum-shaped column in the upper structure and the inner frustum-shaped column in the lower structure can be configured as a continuous gradient structure or a stepped gradient structure.

[0016] This invention proposes a bullseye antenna element, array, and superlens structure. The bullseye antenna element includes a radiating slot and at least two concentric rings. The radiating slot is located on one side of the bullseye antenna element. The feed port of the standard waveguide penetrates the bullseye antenna element from the other side and connects to the radiating slot. A gradient design is adopted between the feed port of the standard waveguide and the radiating slot. Each concentric ring is arranged around the radiating slot as the center, and each concentric ring has a different radius. The radiating slot generates directional radiation based on the feed of the standard waveguide and the electromagnetic resonance generated by the concentric rings. The gradient design between the radiating slot and the feed port of the standard waveguide optimizes impedance matching, enabling the antenna to maintain good performance over a wide frequency range. The low profile of the structure design makes it suitable for lightweight and integrated deployment scenarios. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of the first embodiment of the bullseye antenna unit of the present invention; Figure 2 The simulation diagram of the return loss of the dual-loop antenna in the first embodiment of the bullseye antenna unit of the present invention; Figure 3 This is a simulation diagram of the E-plane direction of the dual-loop antenna in the first embodiment of the bullseye antenna unit of the present invention; Figure 4 This is a simulation diagram of the return loss of the ten-ring antenna in the first embodiment of the bullseye antenna unit of the present invention; Figure 5 This is a simulation diagram of the E-plane direction of the ten-ring antenna in the first embodiment of the bullseye antenna unit of the present invention; Figure 6 This is a front view of the structure of an embodiment of the bullseye antenna array of this application; Figure 7 This is a schematic diagram of the multi-dimensional structure of an embodiment of the bullseye antenna array of this application; Figure 8 This is a simulation diagram of the return loss of an embodiment of the bullseye antenna array of this application; Figure 9These are simulation diagrams of the E-plane and H-plane orientations of an embodiment of the bullseye antenna array of this application; Figure 10 This is a schematic diagram of one embodiment of the superlens structure of this application; Figure 11 This is a simulation diagram illustrating the amplitude variation of the superlens unit S21 in one embodiment of the superlens structure of this application. Figure 12 This is a simulation diagram illustrating the phase modulation value change of a superlens unit in one embodiment of the superlens structure of this application. Figure 13 This is a schematic diagram of the structure of a superlens array according to an embodiment of the superlens structure of this application; Figure 14 This is a comparative schematic diagram of the E-plane orientation pattern of one embodiment of the superlens structure of this application.

[0019] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention. It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly. Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0021] Currently, terahertz wireless communication mostly employs large-aperture, high-gain antennas such as horn antennas or reflector antennas to compensate for path loss of terahertz waves in space. However, these two types of antennas typically have a large profile thickness. For horn antennas to achieve high gain, the ratio of profile thickness to aperture area must satisfy a certain relationship, and the profile thickness of reflector antennas is related to the focal length. These two types of high-gain antennas are difficult to deploy in a lightweight manner.

[0022] Bullseye antennas, as a type of antenna that enhances radiation directivity through periodic structural resonance, are characterized by their simple structure, low profile, and ease of integration. The gain of a bullseye antenna is related to the number of concentric rings (aperture area). However, traditional bullseye antennas have a narrow operating bandwidth and are not easily assembled into antenna arrays.

[0023] This application proposes a waveguide-fed bullseye antenna to solve the above problems. A standard waveguide is used for feeding, and the radiation slot from the waveguide feed port to the bullseye antenna employs a gradient design to achieve better impedance matching.

[0024] Reference Figure 1 , Figure 1 This is a schematic diagram of the structure of the first embodiment of the bullseye antenna element of the present invention, based on Figure 1 A bullseye antenna element is proposed.

[0025] In this embodiment, the bullseye antenna element is fed by a standard waveguide. The bullseye antenna element includes a radiating slot 101 and at least two concentric rings 102. The radiating slot is located on one side of the bullseye antenna element. The feed port of the standard waveguide penetrates the bullseye antenna element from the other side and connects to the radiating slot. The feed port of the standard waveguide and the radiating slot adopt a gradient design. Each concentric ring is arranged around the radiating slot as the center, and each concentric ring has a different radius.

[0026] It should be noted that the radiation gap can generate directional radiation based on the feeding of the standard waveguide and the electromagnetic resonance generated by each of the concentric rings.

[0027] Understandably, a bullseye antenna element can be a basic antenna element that uses a periodic structure (concentric rings) to resonate and enhance radiation directivity. Its core consists of a radiating slot and at least two concentric rings, fed by a standard waveguide, and features simple structure, low profile, and easy integration. Unlike traditional bullseye antennas, the bullseye antenna element in this application optimizes impedance matching through a gradient design and enhances radiation directivity through electromagnetic resonance of the concentric rings. The radiating slot can be a narrow, elongated structure located on one side of the bullseye antenna element, capable of converting received electromagnetic energy into spatial radiation energy. The concentric rings can be a ring-shaped structure with different radii centered on the radiating slot, with at least two rings. The slot width and ring width of each ring affect the antenna resonant frequency, determining the radiation pattern focusing effect. By generating electromagnetic resonance, the radiation directivity of the radiating slot is enhanced, improving the antenna gain. As the number of rings increases, the antenna aperture area increases, thus increasing gain, but return loss gradually deteriorates. Furthermore, the increased aperture area is not conducive to lightweight deployment. Figure 1 This is a schematic diagram of the front view and cross-section of a two-ring bullseye antenna.

[0028] It should be understood that a standard waveguide can be an electromagnetic energy transmission structure conforming to a specific operating frequency band size standard, used to provide feed for a bullseye antenna element. Its size is selected based on the standard waveguide aperture size corresponding to the antenna's operating frequency band. The length of the standard waveguide can be selected according to actual needs; it can be directly mounted on the antenna element via a flange, or it can be installed after extending a certain length. This length has no impact on performance.

[0029] It should be noted that the trapezoidal transition structure used between the standard waveguide feed port and the radiation slot reduces the reflection loss of electromagnetic energy at the connection between the feed port and the radiation slot, achieving a gradual impedance transition and thus widening the antenna's operating bandwidth.

[0030] Furthermore, the thickness of the bullseye antenna element, the length of the radiating slot, the width of the radiating slot, the slot width of the concentric ring, and the width of the concentric ring are all set based on the center frequency of the antenna operation.

[0031] In one possible implementation, Figure 1 The structural parameters of the bullseye antenna element are as follows: The outer contour of the element antenna can be square or circular. When there are two concentric rings in the bullseye antenna element, the outer contour of the element antenna is w = r1 + (2*s + g) + d. When there are N concentric rings in the bullseye antenna element, the outer contour of the element antenna is w = r1 + (N*s + (N-1)*g) + d.

[0032] Where w is the outer contour dimension of the antenna element, and d can take any positive value with little impact on performance. r1 is the distance from the center of the radiation slot of the bullseye antenna element to the outer ring of the innermost concentric ring. s is the width of the concentric ring slot, and g is the width of the concentric ring.

[0033] Furthermore, increasing the thickness h1 of the bullseye antenna element is beneficial for impedance matching, but excessive thickness is detrimental to lightweight deployment. Therefore, the recommended value for the thickness h1 of the bullseye antenna element is 1.6-1.9 wavelengths of the antenna's operating center frequency. The center frequency can be the reference core frequency used in the design, manufacturing, and operation of the bullseye antenna element. The length lo of the radiating slot directly affects the operating center frequency, with lo ranging from 0.52-0.57 wavelengths of the center frequency. The width wo of the radiating slot affects impedance matching, with wo ranging from 0.21-0.23 wavelengths of the center frequency.

[0034] It should be noted that the width 's' of the concentric ring gap directly affects the resonant frequency and determines whether the radiation pattern can be focused; the value of 's' ranges from 0.52 to 0.57 wavelengths of the center frequency. Similarly, the width 'g' of the concentric ring directly affects the resonant frequency and determines whether the radiation pattern can be focused; the value of 'g' ranges from 0.39 to 0.41 wavelengths of the center frequency. Figure 1 The distance from the center of the radiating slot of the bullseye antenna element to the outer ring of the innermost concentric ring is r1 = lo / 2 + g, and the distance from the center of the radiating slot of the bullseye antenna element to the inner ring of the outermost concentric ring is r2 = r1 + s.

[0035] Reference Figure 2 and Figure 3 , Figure 2 This is a simulation diagram of the return loss of the dual-loop antenna in the first embodiment of the bullseye antenna element of the present invention. Figure 3 This is a simulation diagram of the E-plane direction of the dual-loop antenna in the first embodiment of the bullseye antenna element of the present invention. Taking the two-loop bullseye antenna element at the center frequency of 220GHz as an example, the simulation results of the element antenna are as follows. Figure 2 and Figure 3 As shown, this embodiment exhibits a return loss of less than -10dB within the 190-240GHz frequency band, representing a significant improvement in bandwidth compared to traditional bullseye antennas.

[0036] It should be understood that as the number of rings increases, the aperture area of ​​the antenna element increases, thereby improving gain, but return loss gradually deteriorates. Furthermore, the increased aperture area hinders lightweight deployment. (Refer to...) Figure 4 and Figure 5 , Figure 4 This is a simulation diagram of the return loss of the ten-ring antenna in the first embodiment of the bullseye antenna element of the present invention. Figure 5 This is a simulation diagram of the E-plane direction of the ten-ring antenna in the first embodiment of the bullseye antenna element of the present invention. Figure 4 and Figure 5 As shown, the gain of the ten-ring bullseye antenna element is significantly improved compared to the dual-ring type, but the return loss in the 210-220GHz range is also somewhat degraded.

[0037] In this embodiment, the bullseye antenna element is fed by a standard waveguide. The bullseye antenna element includes a radiating slot and at least two concentric rings. The radiating slot is located on one side of the bullseye antenna element. The feed port of the standard waveguide penetrates the bullseye antenna element from the other side and connects to the radiating slot. A gradient design is used between the feed port of the standard waveguide and the radiating slot. Each concentric ring is arranged around the radiating slot as the center, and each concentric ring has a different radius. The radiating slot generates directional radiation based on the feed of the standard waveguide and the electromagnetic resonance generated by the concentric rings. The gradient design between the radiating slot and the feed port of the standard waveguide of the bullseye antenna element optimizes impedance matching, enabling the antenna to maintain good performance over a wide frequency range. The low profile of the structure design makes it suitable for lightweight and integrated deployment scenarios.

[0038] Furthermore, to achieve the above objectives, the present invention also proposes a bullseye antenna array, referring to... Figure 6 , Figure 6 This is a front view of the structure of an embodiment of the bullseye antenna array of this application. Figure 6 As shown, the bullseye antenna array includes at least two of the aforementioned bullseye antenna elements. The bullseye antenna elements are arranged in an array.

[0039] It should be noted that each of the bullseye antenna elements includes the same number of concentric rings. The concentric rings with the same number in adjacent bullseye antenna elements intersect and merge, and the merged concentric ring does not intersect or overlap with concentric rings with a number lower than that number.

[0040] Understandably, a bullseye antenna array arranges at least two bullseye antenna elements in a regular pattern according to a preset direction (first direction x and second direction y) and a fixed spacing (first direction spacing px and second direction spacing py). Within each bullseye antenna element, they are numbered sequentially from the inside out (closer to the radiating slot is the inner side, farther away is the outer side). Rings with the same number in different elements are concentric rings with the same number (for example, each antenna element can include ring #1, ring #2, etc.). After the array is arranged, concentric rings with the same number in adjacent bullseye antenna elements will overlap due to the reduced spacing. These overlapping areas are integrated into a continuous ring structure. After merging the concentric rings, the portions that do not overlap with the smaller inner concentric rings must be retained, and the overlapping areas are deleted to ensure that each ring with its number works independently without structural conflicts.

[0041] It should be understood that because the outer dimensions of a bullseye antenna element are much larger than half a wavelength, when bullseye antenna elements are arrayed, even if the edges are closely connected, the spacing between the center of the structure is still much larger than half a wavelength, resulting in an increase in the sidelobe level of the radiation pattern. Therefore, this scheme shortens the spacing between the center of the structure and reduces the sidelobe level after the element antenna array is formed by merging concentric rings of the same number in each element without intersecting with concentric rings of a smaller number.

[0042] Furthermore, in the bullseye antenna array, the center-to-center spacing of the radiating slots of two adjacent bullseye antenna elements along the first direction and the center-to-center spacing of the radiating slots of two adjacent bullseye antenna elements along the second direction are both set according to the center frequency of the antenna operation, and the first direction and the second direction are perpendicular to each other.

[0043] exist Figure 6 The example uses a 2×2 array with a two-ring structure for the bullseye antenna elements. The front, side, oblique, and rear views of this example are shown below. Figure 7 As shown, Figure 7 This is a schematic diagram of the multidimensional structure of an embodiment of the bullseye antenna array of this application. First, the radiating slots are arranged with a spacing of px in the x-direction (first direction) and a spacing of py in the y-direction (second direction). Then, the concentric ring structures with the same number for each antenna element are intersected and merged. Since there is no 0# ring structure inside ring #1, it only needs to be simply intersected and merged. After merging ring #2, there will be overlap with ring #1 on the inside. Therefore, only the part that does not intersect with rings smaller than 1# is retained to form that part of the concentric ring. If the number of rings in the element antenna is greater than 2, then this process continues. The final front view of the array structure resembles a petal-shaped concentric ring.

[0044] It should be noted that since the unit antenna is fed by a standard waveguide, and the size of the standard waveguide is often larger than the wavelength of the center frequency, and the spacing of the radiation slots is reduced, the coupling between the units will be enhanced, resulting in a deterioration of the array return loss. Increasing the spacing will increase the sidelobe level.

[0045] In one possible implementation, the center-to-center spacing px of the radiating slots of two adjacent bullseye antenna elements along the first direction ranges from 0.57 to 0.61 wavelengths of the center frequency. The center-to-center spacing py of the radiating slots of two adjacent bullseye antenna elements along the second direction ranges from 0.78 to 0.82 wavelengths of the center frequency. (Refer to...) Figure 8 and Figure 9 , Figure 8 This is a simulation diagram of the return loss of an embodiment of the bullseye antenna array of this application. Figure 9The figures show simulation diagrams of the E-plane and H-plane directions of an embodiment of the bullseye antenna array of this application. The simulation results of the return loss under the condition of equal amplitude and in-phase excitation at all four ports are as follows: Figure 8 As shown, the simulation results of the E-plane and H-plane radiation patterns at 220 GHz are as follows: Figure 9 As shown. The aforementioned bullseye antenna elements and bullseye antenna arrays are manufactured using methods including, but not limited to, high-precision machining and 3D printing.

[0046] In this embodiment, the bullseye antenna array includes at least two of the aforementioned bullseye antenna elements; each bullseye antenna element is arranged in an array; each bullseye antenna element includes the same number of concentric rings, and concentric rings with the same number in adjacent bullseye antenna elements intersect and merge, and the merged concentric ring does not intersect or overlap with concentric rings with a smaller number. The structural form of the array presents a petal-shaped or ripple-shaped concentric ring pattern, that is, concentric rings with the same number of rings merge and intersect on the structure, while the overlapping area with the inner concentric ring structure with a smaller number of rings is deleted. By shortening the element spacing, the radiated energy is highly concentrated on the main lobe, improving energy utilization efficiency.

[0047] Furthermore, to achieve the above objectives, the present invention also proposes a superlens structure, referring to... Figure 10 , Figure 10 This is a schematic diagram of one embodiment of the superlens structure of this application. Figure 10 As shown, the bullseye antenna array includes a superlens array and the aforementioned bullseye antenna array; the superlens array is disposed on the bullseye antenna array and connected by mechanical alignment and direct fixing. The superlens array includes multiple superlens units; each superlens unit is uniformly distributed based on multiple angular intervals of the superlens array, and the phase modulation range of the superlens units with different angular intervals is different.

[0048] The superlens unit includes an upper structure 201 and a lower structure 202; the center lines of the upper structure and the lower structure coincide; the upper structure is configured as a frustum-shaped column, and the lower structure is configured as a cuboid with an inwardly tapered frustum-shaped column; the radius of the frustum-shaped column of the upper structure and the inwardly tapered frustum-shaped column of the lower structure gradually decreases along the height direction of the column cross-section.

[0049] Understandably, to further improve the gain of the antenna and array, this scheme designs a three-dimensional superlens unit structure with high transmittance (S21) and a 0-360° phase modulation range. A schematic diagram of this superlens unit structure is shown below. Figure 10 As shown, this unit structure consists of two parts: an upper frustum-shaped column and a lower cuboid composed of an inwardly tapered frustum-shaped column.

[0050] Furthermore, the width of the upper surface, the width of the lower surface, and the height of the upper structure are set based on the center frequency of the antenna operation. The upper surface width of the inner-cut frustum-shaped column in the lower structure is the same as the upper surface width of the upper structure, the lower surface width of the inner-cut frustum-shaped column in the lower structure is the same as the lower surface width of the upper structure, and the height of the inner-cut frustum-shaped column in the lower structure is set based on the center frequency of the antenna operation.

[0051] In one possible implementation, a smaller upper surface width w1 of the frustum-shaped column (upper and lower structures) is more beneficial for improving transmittance, but a very small value is difficult to manufacture in practice. The value of the upper surface width w1 ranges from 0.034 to 0.38 wavelengths of the center frequency. A larger lower surface width w2 of the frustum-shaped column (upper and lower structures) is more beneficial for improving transmittance, but when the value equals the width a of the lower cuboid, it is difficult to manufacture in practice. The value of the lower surface width w2 ranges from 0.143 to 0.152 wavelengths of the center frequency. A larger height l of the inner-cut frustum-shaped column in the lower structure is more beneficial for improving transmittance, but a larger value makes manufacturing more difficult. The value of l ranges from 0.17 to 0.2 wavelengths of the center frequency. The height h2 of the upper structure controls the phase modulation range of the control structure; within a suitable value range, the unit structure can achieve a phase modulation range of 0-360°. However, excessively small or large values ​​will degrade the transmittance. The height h2 of the upper structure, ranging from 0.44 to 1.27 wavelengths of the center frequency, allows for 0-360° phase modulation, while S21 is less than 0.2 dB. The width 'a' of the lower cuboid controls the lattice size of the control structure. Smaller values ​​result in finer phase distribution resolution, leading to better phase compensation from the superlens. However, smaller values ​​also increase the difficulty of actual manufacturing. Increasing the thickness 't' of the lower cuboid will worsen the transmittance but is beneficial for manufacturing. (Refer to...) Figure 11 and Figure 12 , Figure 11 This is a simulation diagram illustrating the amplitude variation of the superlens unit S21 in one embodiment of the superlens structure of this application. Figure 12 This is a simulation diagram illustrating the phase modulation value change of a superlens unit according to an embodiment of the superlens structure of this application. The values ​​are set as a = 0.5 mm and t = 0.4 mm. The simulation results show that the phase modulation range in a typical example is between 0 and 360°, and the amplitude of S21 is less than -0.15 dB.

[0052] Understandably, traditional stepped or cylindrical lenses exhibit significant electromagnetic impedance abrupt changes at the interface, especially in high-frequency bands (such as millimeter waves and terahertz bands), leading to significant reflection and wavefront distortion, thereby reducing focusing efficiency and radiation gain. The inwardly tapered frustum column structure in this embodiment forms a spatial transition structure similar to a tapered impedance gradient by gradually narrowing the column cross-section along its height. This structure allows for a gradual transition in wave impedance as electromagnetic waves enter the lens medium from free space, effectively reducing reflectivity and improving the transmittance of the incident wave and the overall focusing performance of the lens. The tapered design makes the lens surface a near-matching layer, significantly reducing the reflection of incident electromagnetic waves at this interface, achieving optimal matching, especially across a wide frequency range. It better maintains the wavefront shape of the electromagnetic wave within the penetrating lens body, facilitating precise focusing and improving far-field directivity. Compared to complex curved surface structures such as cones, the frustum column is easier to manufacture, suitable for micro / nano-scale precision processing technologies (such as 3D micromachining and photolithography), and facilitates dense arrangement to achieve high fill rates.

[0053] Compared to ordinary straight cylindrical superlens structures, the frustum-shaped column in this embodiment has stronger reflection suppression capabilities; compared to complex non-cylindrical gradient structures, it has a simple structure and is easy to manufacture, while maintaining excellent electromagnetic wave transmission and focusing performance; it has wide bandwidth adaptability and is suitable for multi-band integrated antenna systems, and is suitable for use in the large-aperture structure of the bullseye antenna array proposed in this application.

[0054] Furthermore, the aforementioned superlens units are combined to form a superlens array. A typical example of a superlens array has a size of 5mm*5mm and consists of a total of 10,000 superlens units. The h2 parameter value of each superlens unit is determined based on the extracted phase distribution values ​​of the two-ring bullseye antenna and is quantized at 5° intervals, resulting in a total of 72 h2 parameter values, ultimately forming a typical example of a superlens array. (Refer to...) Figure 13 and Figure 14 , Figure 13 This is a schematic diagram of the structure of a superlens array according to an embodiment of the superlens structure of this application. Figure 14 This is a comparative schematic diagram of the E-plane radiation pattern of one embodiment of the superlens structure of this application. Figure 14 The E-plane radiation patterns of a typical example single antenna and a typical example superlens antenna are compared.

[0055] Understandably, bullseye antenna arrays can be mechanically integrated with a superlens structure located above the antenna. The array assembly and superlens are connected via mechanical alignment and direct fixation, making it less prone to lens shift or performance fluctuations due to vibration, thermal expansion, or other factors in practical applications. This significantly improves system structural stability, simplifies assembly, and facilitates integrated deployment of the array-lens co-design. The connection aligns the superlens's focal point with the array's main lobe, creating a far-field beam with higher directivity and gain. Compared to the independent operation mode of traditional bullseye antenna arrays, this further enhances gain.

[0056] The above description is only a preferred embodiment of the present invention and does not limit the scope of protection of the present invention. All equivalent structural transformations made under the inventive concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included within the scope of protection of the present invention.

Claims

1. A bowtie antenna element, characterized by The bovine eye antenna unit is fed by a standard waveguide, and the bovine eye antenna unit comprises: a radiation slot and at least two concentric rings; The radiation slot is arranged on one side of the bovine eye antenna unit, a feeding port of the standard waveguide penetrates the bovine eye antenna unit from the other side of the bovine eye antenna unit, and the feeding port of the standard waveguide is connected with the radiation slot, a gradual change design is adopted between the feeding port of the standard waveguide and the radiation slot, each of the concentric rings is arranged around the radiation slot as a center ring, and each of the concentric rings is provided with a different radius; The radiation slot generates directional radiation based on the feeding of the standard waveguide and electromagnetic resonance generated by each of the concentric rings.

2. The bullseye antenna element of claim 1, wherein, The thickness of the bovine eye antenna unit, the length of the radiation slot, the width of the radiation slot, the slot width of the concentric ring, and the width of the concentric ring are all set based on a center frequency point of antenna operation.

3. A cattle eye antenna array characterized by, The bovine eye antenna array comprises at least two bovine eye antenna units according to any one of claims 1 to 2; Each of the bovine eye antenna units is arranged in an array; Each of the bovine eye antenna units comprises the same number of concentric rings, the same number of concentric rings in adjacent bovine eye antenna units are combined, and the combined concentric rings do not intersect with the concentric rings smaller than the number.

4. The bullseye antenna array of claim 3, wherein, In the bovine eye antenna array, the center distance of the radiation slots of two adjacent bovine eye antenna units in a first direction and the center distance of the radiation slots of two adjacent bovine eye antenna units in a second direction are both set according to a center frequency point of antenna operation, and the first direction and the second direction are perpendicular to each other.

5. A metalens structure, characterized in that, The superlens structure comprises: a superlens array and a bovine eye antenna array according to any one of claims 3 to 4; The superlens array is arranged on the bovine eye antenna array and connected in a mechanical alignment and direct fixing manner.

6. The metalens structure of claim 5, wherein, The superlens array comprises: a plurality of superlens units; Each of the superlens units is uniformly distributed based on a plurality of angle intervals of the superlens array, and the phase modulation ranges of the superlens units with different angle intervals are different.

7. The metalens structure of claim 6, wherein, The superlens unit comprises: an upper half structure and a lower half structure; The center lines of the upper half structure and the lower half structure coincide; The upper half structure is arranged as a trapezoidal column, and the lower half structure is arranged as a cuboid with an inner truncated trapezoidal column; The trapezoidal column of the upper half structure and the inner truncated trapezoidal column of the lower half structure gradually decrease in radius along the height direction of the column cross section.

8. The metalens structure of claim 7, wherein, The upper surface width of the upper half structure, the lower surface width of the upper half structure, and the height of the upper half structure are set based on a center frequency point of antenna operation.

9. The metalens structure of claim 8, wherein, The upper surface width of the inner truncated trapezoidal column in the lower half structure is the same as the upper surface width of the upper half structure, the lower surface width of the inner truncated trapezoidal column in the lower half structure is the same as the lower surface width of the upper half structure, and the height of the inner truncated trapezoidal column in the lower half structure is set based on a center frequency point of antenna operation.

10. The metalens structure of claim 7, wherein, The inclined edges of the trapezoidal column of the upper half structure and the inner truncated trapezoidal column of the lower half structure are arranged as a continuous gradual change structure or a stepped gradual change structure.

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