Sub-THz focal control hyperlens antenna based on alvarez lens and design method

Abstract

The application provides a Sub-THz focal control superlens antenna based on an Alvarez lens and a design method, and belongs to the technical field of superlens antennas. The antenna is suitable for a Sub-THz frequency band of 100-300 GHz, the antenna adopts a two-layer pure-phase superlens cascade structure, and the pure-phase superlens is composed of superlens unit cells in a subwavelength scale and arranged in an equal-interval mode in the horizontal direction and the vertical direction. By making the upper and lower pure-phase superlenses horizontally and synchronously reversely translate and changing the translation distance, the focal point can be adjusted at a working frequency of 200 GHz, and the focal point control range is 10.02 mm-66.88 mm. The application can break through the bottleneck of the volume, integration, focusing efficiency and cost of a traditional antenna in a sub-terahertz frequency band, realize the miniaturization, light weight and high performance of an antenna system, and provide a reliable antenna solution for related fields such as sub-terahertz communication and radar imaging.

Description

Technical Field

[0001] This invention belongs to the field of superlens antenna technology, specifically relating to a Sub-THz focus-controlled superlens antenna based on an Alvarez lens and its design method. Background Technology

[0002] The Asia-Pacific Hertz band Sub-THz (frequency 100–300 GHz) covers multiple key sub-bands such as D, W, and H. As a core transitional band between millimeter waves and terahertz, its most prominent advantage is that it has tens of GHz of continuous available bandwidth. This makes it the core physical foundation for supporting the breakthrough of existing performance bottlenecks in sixth-generation mobile communication (6G) and post-5G technologies, achieving Tbps-level ultra-high transmission rates and millisecond-level ultra-low latency communication. It is also a key breakthrough in solving the current problem of "insufficient bandwidth and limited speed" in wireless communication.

[0003] It possesses irreplaceable advantages in scenarios such as indoor ultra-high-speed access, vehicle-to-everything (V2X) communication, and radar imaging. However, behind the advantages brought by high-frequency bands lie significant technical challenges—the higher the frequency of electromagnetic waves, the greater their free-space propagation loss. Furthermore, the diffraction ability of Asia-Pacific Hertz (APH) signals to common obstacles such as walls, people, and raindrops is extremely strong or weak, making them prone to signal attenuation or even interruption, severely affecting the stability and coverage of communication links. To overcome this core challenge and establish a reliable APH communication link, it is essential to rely on a high-gain, narrow-beam antenna system with rapid focusing and beam switching capabilities. By increasing antenna gain to compensate for signal transmission loss and leveraging flexible beam control capabilities to adapt to complex propagation environments, the stable establishment and efficient operation of the communication link can be ensured.

[0004] However, in the Asia-Pacific Hertz band, traditional antenna array solutions face many insurmountable technical bottlenecks: due to the limitations of frequency band characteristics, the unit size and overall volume of traditional antenna arrays are difficult to miniaturize, which is not conducive to integration into terminal equipment, base stations or vehicle systems; the design complexity of the feed network is greatly increased, and the feed loss at high frequencies is significantly increased, further reducing the overall performance of the antenna system; at the same time, the heat generated by the antenna array during operation is difficult to dissipate quickly, resulting in prominent thermal management problems, which can easily lead to antenna performance degradation and decreased stability; in addition, the beam control of traditional antenna arrays mostly relies on complex phase shifters and drive structures, resulting in slow control response speed, which cannot meet the requirements of Asia-Pacific Hertz communication for rapid beam switching and is difficult to adapt to dynamically changing communication scenarios. Summary of the Invention

[0005] Addressing the core pain points and technical limitations of traditional antenna solutions in the Asia-Pacific Hertz communication field, this invention innovatively combines the continuous zoom mechanism of the Alvarez lens with the planar and highly integrated advantages of the superlens, proposing a dynamic focusing, small size, low cost, and high performance superlens antenna design scheme, namely, a Sub-THz focus-controlled superlens antenna based on the Alvarez lens and its design method.

[0006] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention proposes a Sub-THz focus-controlled superlens antenna based on an Alvarez lens. The antenna is suitable for the Sub-THz frequency band of 100–300 GHz. The antenna adopts a two-layer pure phase superlens cascade structure. The pure phase superlens is composed of subwavelength scale superlens unit cells arranged at equal intervals in the lateral and longitudinal directions. By making the upper and lower pure phase superlenses perform synchronous reverse lateral translation and changing the translation distance, the antenna focus can be continuously adjusted at the operating frequency of 200 GHz.

[0007] Furthermore, the continuously adjustable range of the antenna focus described in this invention is 10.02mm-66.88mm.

[0008] Furthermore, the meta-lens unit cell of the present invention adopts a square column structure with a central hole to change the unit duty cycle. The period length P of the unit is 0.75 mm and the height H of the square column is 2 mm.

[0009] Furthermore, the side length of the hole pillar structure with the central hole in the present invention is adjustable. When the side length D of the hole pillar structure with the hole is varied in the range of 0.11mm to 0.74mm, the meta-lens unit cell can achieve continuous phase modulation in the range of 0 to 2π.

[0010] Furthermore, the pure phase meta-lens of the present invention is made of photosensitive resin material, and the relative permittivity of the photosensitive resin material is 3.0 in the 200GHz frequency band.

[0011] Furthermore, the phase response functions of both pure phase metalenses are highly complementary to the freeform surface of the Alvarez lens.

[0012] Furthermore, when a plane electromagnetic wave is incident, it first undergoes preliminary phase modulation through the first layer of pure phase meta-lens, and then undergoes secondary phase compensation through the second layer of pure phase meta-lens. By phase modulation, compensation, and changing the lateral displacement distance, the beam can be focused and zoomed.

[0013] Furthermore, the two pure phase meta-lenses are tightly fitted together to avoid off-axis phase difference.

[0014] Furthermore, when the two pure phase metalenses are horizontally aligned, the combined phase function is 0, resulting in no phase modulation effect on the incident wavefront.

[0015] Secondly, based on the same inventive concept, the present invention also provides a design method for a Sub-THz focus-controlled superlens antenna based on an Alvarez lens, the method comprising the following steps: By analyzing the phase distribution of the upper and lower double-layer metalenses and the overall phase distribution when the lateral distance between the two layers is changed synchronously in opposite directions, the formulas relating the focusing parameter A to the focal length f and the lateral distance d are obtained. Based on the aforementioned correlation formula, the focusing parameter A is set to 0.01. Simultaneously, the pure phase metalens is designed as a 30×30 array structure, with a period size of 0.75mm for the metalens unit cell, resulting in an overall array size of 22.5mm×22.5mm for the metalens. The core operating frequency of the antenna is set to 200GHz, and the two layers of pure phase metalenses are tightly bonded together to avoid off-axis phase difference.

[0016] The beneficial effects of this invention are as follows: The proposed solution operates in the Asia-Pacific Hertz (Sub-THz) band, enabling a stable continuous zoom range from 10.02 mm to 66.88 mm. By leveraging the complementary advantages of both methods, this solution aims to overcome the bottlenecks of traditional antennas in the Asia-Pacific Hertz band regarding size, integration, focusing efficiency, and cost. It will achieve miniaturization, lightweight design, and high performance of antenna systems, providing a reliable antenna solution for Asia-Pacific Hertz communication, radar imaging, and related fields. Attached Figure Description

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

[0018] Figure 1 This is a structural diagram of the metalens unit cell described in this invention, wherein... Figure 1 (a) in the figure is a 3D diagram. Figure 1 (b) is the top view; Figure 2 The figures show the full-wave simulation results of the amplitude and phase of the unit cell described in this invention. Figure 2 (a) in the figure is the full-wave amplitude simulation diagram. Figure 2 (b) in the figure is a full-wave phase simulation diagram; Figure 3 This is a schematic diagram of the operation of the meta-lens described in this invention; Figure 4 This invention provides a 3D array model of a Sub-THz focus-controlled superlens antenna based on an Alvarez lens, as described in this invention. Figure 4 (a) in the image is a top view. Figure 4 (b) in the figure is a three-dimensional image; Figure 5 This refers to the phase distribution of the lower superlens when the translation distance d is 0, as described in this invention. Figure 6 This refers to the phase distribution of the upper superlens when the translation distance d is 0, as described in this invention. Figure 7 This refers to the phase distribution of the lower superlens described in this invention when the translation distance d is 8. Figure 8 This refers to the phase distribution of the upper superlens described in this invention when the translation distance d is 8. Figure 9 This refers to the total phase distribution when the translation distance d is 8, as described in this invention. Figure 10 The simulated intensity of the xoz plane when the translation distance d is 8, as described in this invention; Figure 11 The simulated intensity of the xoy plane when the translation distance d is 8, as described in this invention; Figure 12 This refers to the phase distribution of the lower superlens described in this invention when the translation distance d is 5. Figure 13 This refers to the phase distribution of the upper superlens described in this invention when the translation distance d is 5. Figure 14 This refers to the total phase distribution when the translation distance d is 5, as described in this invention. Figure 15 The simulated intensity of the xoz plane when the translation distance d is 5, as described in this invention; Figure 16 The simulated intensity of the xoy plane when the translation distance d is 5, as described in this invention; Figure 17 This refers to the phase distribution of the lower superlens described in this invention when the translation distance d is 1. Figure 18 This refers to the phase distribution of the upper superlens described in this invention when the translation distance d is 1. Figure 19 This refers to the total phase distribution when the translation distance d is 1, as described in this invention. Figure 20 The simulated intensity of the xoz plane when the translation distance d is 1, as described in this invention; Figure 21 The simulated intensity of the xoy plane when the translation distance d is 1, as described in this invention. Detailed Implementation The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

[0019] Example 1, Combination Figures 1 to 4 This embodiment addresses the core pain points in the Asia-Pacific Hertz communication field and the technical limitations of traditional antenna solutions. It innovatively combines the continuous zoom mechanism of the Alvarez lens with the planar and highly integrated advantages of a superlens, proposing a Sub-THz focus-controlled superlens antenna based on an Alvarez lens. The antenna is suitable for the 100–300 GHz Sub-THz frequency band and employs a two-layer pure-phase superlens cascade structure. The pure-phase superlens is composed of subwavelength-scale superlens unit cells arranged at equal intervals in the lateral and longitudinal directions. By synchronously and in opposite directions laterally translating the upper and lower pure-phase superlenses and changing the translation distance, focus adjustment can be achieved at a 200 GHz operating frequency, with a focus control range of 10.02 mm to 66.88 mm.

[0020] Furthermore, the metalens unit cell is as follows: Figure 1 As shown, the entire structure consists of a square pillar structure with a central hole. The periodic length of the superunit cell is P = 0.75 mm, and the height H is 2 mm; the height H of the central hole pillar structure is 2 mm. By adjusting the side length D of the central hole pillar structure, the unit cell can be positioned at 0... Continuous phase modulation is achieved within a 2π range. The entire structure is fabricated using a photosensitive resin material commonly used in 3D printing, which has a relative permittivity of approximately 3.0 at 200 GHz. Full-wave simulation results of the amplitude and phase of the unit cell are shown below. Figure 2 As shown, at a working frequency of 200 GHz, when the side length D of the hole column structure with a central hole varies within the range of 0.11 mm to 0.74 mm, the structure can achieve complete 2π phase coverage and has good phase control characteristics.

[0021] Furthermore, the upper and lower pure phase superlenses are mechanically driven to perform synchronous reverse lateral translation and change the translation distance d; the working principle of the reconfigurable zoom superlens component driven by mechanical lateral displacement is as follows: Figure 3As shown in the figure, "M1" represents the first pure phase metalens, and "M2" represents the second pure phase metalens. Both metasurfaces are composed of subwavelength-scale artificial microstructure units, and their phase response functions are designed to be highly complementary to the freeform surface of a traditional Alvarez lens. When a plane electromagnetic wave is incident, it first passes through the first metalens M1, which performs preliminary phase modulation on the incident wavefront; subsequently, the beam enters the second metalens M2, where M2 performs secondary phase compensation on the wavefront modulated by M1. By changing the lateral displacement d, a zoom range of 10.02mm-66.88mm can be achieved. Furthermore, this embodiment also provides a design method for a Sub-THz focus-controlled superlens antenna based on an Alvarez lens, the design method comprising the following steps: By analyzing the phase distribution of the upper and lower double-layer metalenses and the overall phase distribution when the lateral distance between the two layers is changed synchronously in opposite directions, the formulas relating the focusing parameter A to the focal length f and the lateral distance d are obtained. Based on the aforementioned correlation formula, the focusing parameter A is set to 0.01. Simultaneously, the pure phase metalens is designed as a 30×30 array structure, with a period size of 0.75mm for the metalens unit cell, resulting in an overall array size of 22.5mm×22.5mm for the metalens. The core operating frequency of the antenna is set to 200GHz, and the two layers of pure phase metalenses are tightly bonded together to avoid off-axis phase difference.

[0022] The design principle is as follows: Because Alvarez lenses in the optical band are extremely difficult to manufacture, this embodiment uses a metamaterial lens design method.

[0023] The phase distribution of the upper and lower double-layer superlenses is as follows:

[0024] When the two superlenses are horizontally aligned, the combined phase function is 0, indicating that the double-layer cascaded superlenses have no phase modulation effect on the incident wavefront at this time. When the lateral distance d between the two layers is changed synchronously in opposite directions, the overall phase distribution is:

[0025] Where A is related to the focal length f and the lateral distance d:

[0026] Based on the above principle, it can be seen that the zoom function of the Alvarez lens can be achieved by changing the lateral movement distance d. No contribution to the focus. It can achieve focusing functionality. Here, a 30*30 array is designed with a unit size of 0.75mm, an operating frequency of 200GHz, and an A value of 0.01. The overall array surface of the superlens is 22.5mm*22.5mm. To avoid off-axis aberration, the two superlens layers are tightly bonded together. The 3D model is as follows... Figure 4 As shown.

[0027] Example 2, Combination Figures 5 to 21 This embodiment is described below, and the effects and advantages of the present invention are further discussed through simulation. in, Figure 5 The image shows the phase distribution of the lower superlens when the translation distance d is 0; Figure 6 The diagram shows the phase distribution of the upper superlens when the translation distance d is 0. It can be seen that when the two superlenses are horizontally aligned, the combined phase function is 0, indicating that the double-layer cascaded superlens has no phase modulation effect on the incident wavefront.

[0028] Figure 7 The image shows the phase distribution of the lower superlens when the translation distance d is 8. Figure 8 The image shows the phase distribution of the upper superlens when the translation distance d is 8. Figure 9 The figure shows the total phase distribution when the translation distance d is 8; it can be seen that zoom can be achieved by changing the lateral displacement d.

[0029] When the lateral translation distance of the double-layer superlens is changed to 8, the focal position and the energy distribution on the focal plane are shown in Figures 10 and 10. Figure 11 As shown, a clear focal point can be seen, with the focal point located at 10.02 mm in the z-direction.

[0030] Figure 12 The image shows the phase distribution of the lower superlens when the translation distance d is 5. Figure 13 The image shows the phase distribution of the upper superlens when the translation distance d is 5. Figure 14 The figure shows the total phase distribution when the translation distance d is 5; when the lateral translation distance of the double-layer superlens is changed to 5, the results of the focal position and energy distribution on the focal plane are as follows. Figure 15 and Figure 16 As shown, a clear focal point can be seen, with the focal point located at 18.09 mm in the z-direction.

[0031] Figure 17 The image shows the phase distribution of the lower superlens when the translation distance d is 1; Figure 18 The image shows the phase distribution of the upper superlens when the translation distance d is 1; Figure 19The figure shows the total phase distribution when the translation distance d is 1; when the lateral translation distance of the double-layer superlens is changed to 1, the results of the focal position and the energy distribution on the focal plane are as follows. Figure 20 and Figure 21 As shown, a clear focal point can be seen, with the focal point located at 66.88mm in the z-direction.

[0032] By summarizing the simulation structures described above, the data shown in Table 1 demonstrates that this invention achieves continuous and stable focal length adjustment by precisely controlling the lateral relative displacement of the two phase plates of the Alvarez lens. This mechanism fundamentally simplifies the complex mechanical structure of traditional zoom systems that relies on the linkage of multiple lens groups, significantly improving the flexibility of zoom adjustment and system stability. In the Sub-THz frequency band, this zoom system can stably achieve a continuous zoom range of 10.02mm to 66.88mm, opening up a completely new technical path for the miniaturization and cost reduction of Sub-THz frequency band zoom devices.

[0033] Table 1

[0034] It should be understood that, when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0035] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A Sub-THz focus-controlled superlens antenna based on an Alvarez lens, characterized in that, The antenna is suitable for the Sub-THz frequency band of 100–300 GHz. The antenna adopts a two-layer pure phase metalens cascade structure. The pure phase metalens is composed of subwavelength scale metalens unit cells arranged at equal intervals in the horizontal and vertical directions. By making the upper and lower pure phase metalenses synchronously reversed in the horizontal direction and changing the translation distance, the antenna focus can be continuously adjusted at the operating frequency of 200 GHz.

2. The Sub-THz focus-controlled superlens antenna based on an Alvarez lens according to claim 1, characterized in that, The continuously adjustable range of the antenna focal point is 10.02mm-66.88mm.

3. The Sub-THz focus-controlled superlens antenna based on an Alvarez lens according to claim 1, characterized in that, The meta-lens unit cell adopts a square column structure with a central hole to change the unit's duty cycle. The period length P of the unit is 0.75 mm, and the height H of the square column is 2 mm.

4. The Sub-THz focus-controlled superlens antenna based on an Alvarez lens according to claim 3, characterized in that, The side length of the hole pillar structure with the central hole is adjustable. When the side length D of the hole pillar structure varies in the range of 0.11mm to 0.74mm, the meta-lens unit cell can achieve continuous phase modulation in the range of 0 to 2π.

5. A Sub-THz focus-controlled superlens antenna based on an Alvarez lens according to claim 1, characterized in that, The pure phase meta-lens is made of photosensitive resin material, and the relative permittivity of the photosensitive resin material is 3.0 in the 200GHz frequency band.

6. The Sub-THz focus-controlled superlens antenna based on an Alvarez lens according to claim 1, characterized in that, The phase response functions of both pure phase metalenses are highly complementary to the freeform surface of the Alvarez lens.

7. A Sub-THz focus-controlled superlens antenna based on an Alvarez lens according to claim 1, characterized in that, When a plane electromagnetic wave is incident, it first undergoes preliminary phase modulation through the first layer of pure phase meta-lens, and then undergoes secondary phase compensation through the second layer of pure phase meta-lens. The beam is focused and zoomed by phase modulation, compensation, and changing the lateral displacement distance.

8. A Sub-THz focus-controlled superlens antenna based on an Alvarez lens according to claim 1, characterized in that, The two layers of pure phase meta-lenses are tightly fitted together to avoid off-axis phase difference.

9. A Sub-THz focus-controlled superlens antenna based on an Alvarez lens according to claim 1, characterized in that, When the two pure phase metalenses are horizontally overlapped, the combined phase function is 0, and there is no phase modulation effect on the incident wavefront.

10. A design method for a Sub-THz focus-controlled superlens antenna based on an Alvarez lens as described in any one of claims 1-9, characterized in that, Includes the following steps: By analyzing the phase distribution of the upper and lower double-layer metalenses and the overall phase distribution when the lateral distance between the two layers is changed synchronously in opposite directions, the formulas relating the focusing parameter A to the focal length f and the lateral distance d are obtained. Based on the aforementioned correlation formula, the focusing parameter A is set to 0.

01. Simultaneously, the pure phase metalens is designed as a 30×30 array structure, with a period size of 0.75mm for the metalens unit cell, resulting in an overall array size of 22.5mm×22.5mm for the metalens. The core operating frequency of the antenna is set to 200GHz, and the two layers of pure phase metalenses are tightly bonded together to avoid off-axis phase difference.

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