Millimeter wave multi-band Minkowski fractal antenna

Abstract

The invention discloses a millimeter wave multi-band Minkowski-like fractal antenna, relates to the technical field of communication antennas, and solves the technical problem that an antenna capable of realizing multi-band millimeter wave work in a chip-level size and keeping high radiation efficiency is needed urgently. The antenna comprises a radiation structure, a microwave transmission line, a dielectric layer and a grounding layer, the radiation structure and the microwave transmission line are arranged on the dielectric layer, and the microwave transmission line is connected with the radiation structure; the grounding layer is arranged below the dielectric layer; the radiation structure comprises a fractal patch, and the fractal patch is a Minkowski-like fractal structure formed by an original fractal unit and three rotary fractal units; the three rotary fractal units are generated by rotating 90 degrees, 180 degrees and 270 degrees in sequence by taking angular points of the original fractal unit as a reference; the size of the original parting unit is not completely the same as or completely different from the size of the three rotary fractal units. According to the invention, flexible coverage of resonant frequency and multi-band millimeter wave work can be realized, and meanwhile, high radiation efficiency is kept.

Description

Technical Field

[0001] This invention relates to the field of communication antenna technology, and in particular to a millimeter-wave multi-band Minkowski fractal antenna. Background Technology

[0002] With the rapid development of 5G / 6G communication, autonomous driving radar (77 / 94GHz), and high-speed wireless interconnection (60 / 120GHz) technologies, the demand for multi-band millimeter-wave antennas in modern wireless systems is becoming increasingly urgent. A single device needs to be compatible with multiple millimeter-wave frequency bands (such as 60GHz, 77GHz, 94GHz, 120GHz, etc.) to achieve multi-functional integration, system simplification, and performance optimization. Multi-band antennas are of great significance in practical applications: on the one hand, they enable multi-tasking capabilities through a single platform, reducing space occupation and hardware costs, and avoiding the deployment of multiple independent antenna systems, making them particularly suitable for space-constrained mobile platforms or compact devices; on the other hand, different frequency bands exhibit complementary characteristics under different environmental conditions. For example, the 77GHz band has lower attenuation in rainy and foggy environments, while the 94GHz band provides higher resolution in clear weather. Multi-band antennas can dynamically switch operating frequency bands according to the environment, thereby improving system reliability and anti-interference capabilities. Therefore, developing miniaturized, high-efficiency multi-band millimeter-wave antennas has become a core challenge for the industry.

[0003] However, traditional multi-band antenna design faces significant technical bottlenecks. While PCB-based array antennas can support multi-band operation, their size typically exceeds chip-level packaging limits by more than 300%, making it difficult to meet the miniaturization requirements of modern integrated devices. Furthermore, as frequencies rise to the millimeter-wave range, interconnection losses between the antenna and on-chip front-end RF circuitry increase significantly. On the other hand, while semiconductor-based on-chip antennas can achieve chip-level dimensions, their radiation efficiency is generally below 40%, failing to meet the requirements of high-performance applications. Existing technologies have not yet offered effective solutions to these problems. Traditional multi-band antenna designs often rely on complex feed networks or multi-layer stacked structures, resulting in excessive size or low efficiency; while on-chip antennas, limited by process technology and materials, struggle to balance multi-band coverage with high-efficiency radiation.

[0004] In the process of realizing this invention, the inventors discovered at least the following problems in the prior art:

[0005] There is an urgent need for an antenna that can achieve multi-band millimeter-wave operation within a chip-scale size while maintaining high radiation efficiency. Summary of the Invention

[0006] The purpose of this invention is to provide a millimeter-wave multi-band Minkowski fractal antenna to solve the technical problem in the prior art that there is an urgent need for an antenna that can achieve multi-band millimeter-wave operation within a chip-scale size while maintaining high radiation efficiency.

[0007] The preferred technical solutions among the many technical solutions provided by this invention can produce a variety of technical effects, which are described in detail below.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] This invention provides a millimeter-wave multi-band Minkowski-like fractal antenna, comprising a radiating structure, a microwave transmission line, a dielectric layer, and a ground layer; the radiating structure and the microwave transmission line are both disposed on the dielectric layer, and the microwave transmission line is connected to the radiating structure; the ground layer is disposed below the dielectric layer; the radiating structure includes a fractal patch, which is a Minkowski-like fractal structure composed of an original fractal unit and three rotating fractal units; the three rotating fractal units are generated by rotating 90°, 180°, and 270° sequentially from the corner point of the original fractal unit as a reference; the original fractal unit and the three rotating fractals are not all the same size or are all different.

[0010] Optionally, the original fractal unit is based on a rectangle with length L and width W. The upper long side of the rectangle is divided into three equal parts, and a first concave structure is formed in the middle of the third part. The depth of the concave structure is a*W. The left wide side of the rectangle is divided into three equal parts, and a second concave structure is formed in the middle of the third part. The depth of the concave structure is a*L. This forms a first-order Minkowski-like fractal structure. Here, a is a multiple of the concave structure.

[0011] Optionally, the antenna is fabricated using SOI technology; the antenna further includes a GSG pad and a silicon substrate; the GSG pad is disposed on the dielectric layer and connected to the radiating structure through the microwave transmission line; the two ground terminals of the GSG pad are connected to the grounding layer through conductive lines; the silicon substrate is located between the dielectric layer and the grounding layer, and the grounding layer is disposed below the silicon substrate; the thickness of the silicon substrate is 200 μm; the length L = 0.3 mm, the width W = 0.18 mm, and a = 1 / 6 of the original fractal unit; the depth of the first recessed structure is 0.03 mm; the depth of the second recessed structure is 0.05 mm; the size ratio of the original fractal unit to the three rotating fractals is 1:0.8:0.9:0.8.

[0012] Optionally, the fractal patch has a cross-shaped groove at its center, and a 45° oblique groove is provided at the center of both the original fractal unit and the three rotating fractal units.

[0013] Optionally, the radiation layer includes a first metal layer and a second metal layer; the fractal patch is disposed on the first metal layer; four L-shaped holes are provided at the angle between the original fractal unit and the three rotating fractal units located at the rotation center, and rectangular holes are provided on both sides of each of the inclined grooves; a metal block corresponding to the L-shaped holes and rectangular holes is disposed on the second metal layer; the metal block is connected to the fractal patch through a conductive via.

[0014] Optionally, the microwave transmission line is a coplanar waveguide feed line disposed in the second metal layer; the center guide strip of the coplanar waveguide feed line is connected to the radiating structure; the ground plane of the coplanar waveguide feed line is connected to the ground layer through the conductive line; the ground plane of the coplanar waveguide feed line is trapezoidal.

[0015] Optionally, the size of the grounding layer is twice the size of the silicon substrate; the size of the silicon substrate is 800um × 950um, and the size of the grounding layer is 1600um × 1900um.

[0016] Optionally, the antenna is fabricated using PCB technology; the microwave transmission line is a microstrip feed line; the length L = 0.88 mm, width W = 0.6 mm, and a = 4 / 15 of the original fractal unit; the depth of the first recessed structure is 0.16 mm; the depth of the second recessed structure is 3.52 / 15 mm; the size ratio of the original fractal unit to the three rotating fractals is 1:0.63:0.9:0.85.

[0017] Optionally, the dielectric layer is made of Rogers RT 5880 and has a thickness of 0.127 mm; the ground layer is formed by fully covering the lower surface of the dielectric layer with copper; the copper thickness of the ground layer is 22 μm.

[0018] Optionally, the thickness of the radiating structure is 22 μm.

[0019] Implementing one of the above-described technical solutions of the present invention has the following advantages or beneficial effects:

[0020] The millimeter-wave multi-band Minkowski fractal antenna provided by this invention is based on the original fractal unit, and three fractal units are generated with the lower right corner as the rotation center. These four fractal units together constitute the radiation structure. The four fractal units are set to different proportions, so that different combinations of fractal units can present a variety of results, realize flexible coverage of resonant frequencies, and multi-band millimeter-wave operation, while maintaining high radiation efficiency. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0022] Figure 1 This is a schematic diagram of the radiation structure in Embodiment 1 of the present invention;

[0023] Figure 2 This is a schematic diagram of the structure of an antenna on a single chip according to an embodiment of the present invention;

[0024] Figure 3 This is a cross-sectional view of the on-chip antenna in Embodiment 2 of the present invention;

[0025] Figure 4 This is an exploded view of the on-chip antenna in Embodiment 2 of the present invention;

[0026] Figure 5 This is a plan view of the on-chip antenna in Embodiment 2 of the present invention;

[0027] Figure 6 This is the S-parameter diagram of the on-chip antenna simulation in Embodiment 2 of the present invention;

[0028] Figure 7 This is the radiation pattern of the on-chip antenna at 77 GHz in Embodiment 2 of the present invention;

[0029] Figure 8 This is the radiation pattern of the on-chip antenna at 94 GHz in Embodiment 2 of the present invention;

[0030] Figure 9 This is a schematic diagram of the PCB antenna structure according to Embodiment 3 of the present invention;

[0031] Figure 10 This is the S-parameter diagram of the PCB antenna simulation in Embodiment 3 of the present invention;

[0032] Figure 11 This is the radiation pattern of the PCB antenna at 60GHz in Embodiment 3 of the present invention;

[0033] Figure 12 This is the radiation pattern of the PCB antenna at 77GHz in Embodiment 3 of the present invention;

[0034] Figure 13 This is the radiation pattern of the PCB antenna at 94GHz in Embodiment 3 of the present invention;

[0035] Figure 14 This is the radiation pattern of the PCB antenna at 120GHz in Embodiment 3 of the present invention;

[0036] In the figure: 1. Radial structure; 11. Original fractal unit; 12. Rotational fractal unit; 13. First recessed structure; 14. Second recessed structure; 15. Cross-shaped groove; 16. Oblique groove; 17. L-shaped hole; 18. Rectangular hole; 2. Microwave transmission line; 21. Central conductor; 22. Ground plane; 3. Dielectric layer; 4. Ground layer; 5. GSG pad; 6. Silicon substrate; 7. Conductive line. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the present invention clearer, various exemplary embodiments described below will be referenced to the accompanying drawings, which form part of the exemplary embodiments, illustrating various exemplary embodiments that may be used to implement the present invention. Unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. It should be understood that they are merely examples of processes, methods, and apparatuses consistent with some aspects of the present invention disclosed as detailed in the appended claims, and other embodiments may be used, or structural and functional modifications may be made to the embodiments listed herein without departing from the scope and spirit of the present invention.

[0038] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," etc., indicate the orientation or positional relationship based on the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the referred element must have a specific orientation, or be constructed and operated in a specific orientation. The terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. The term "a plurality" means two or more. The terms "connected" and "linked" should be interpreted broadly, for example, they can refer to fixed connections, detachable connections, integral connections, mechanical connections, electrical connections, communication connections, direct connections, indirect connections through an intermediate medium, and can refer to the internal communication of two elements or the interaction relationship between two elements. The term "and / or" includes any and all combinations of one or more of the related listed items. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0039] To illustrate the technical solution described in this invention, specific embodiments are described below, showing only the parts related to the embodiments of this invention.

[0040] Example 1:

[0041] like Figure 1 As shown, this invention provides a millimeter-wave multi-band Minkowski-like fractal antenna, including a radiating structure 1, a microwave transmission line 2, a dielectric layer 3, and a ground layer 4. The radiating structure 1 and the microwave transmission line 2 are both disposed on the dielectric layer 3, and the microwave transmission line 2 is connected to the radiating structure 1. The ground layer 4 is disposed below the dielectric layer 3. The radiating structure 1 includes a fractal patch, which is a Minkowski-like fractal structure composed of an original fractal unit 11 and three rotating fractal units 12. The three rotating fractal units 12 are generated by rotating 90°, 180°, and 270° sequentially, with the corner point of the original fractal unit 11 as a reference. The original fractal unit and the three rotating fractals are not all the same size or are completely different. In this embodiment, the fractal patch is a fractal structure. The similar substructures of different scales in the fractal structure can resonate independently, and the resulting sawtooth / stubs form multi-branch current paths, each with a different electrical length. These characteristics make the fractal structure easier to realize multi-band antenna operation.

[0042] The millimeter-wave multi-band Minkowski fractal antenna provided in this embodiment is based on the original fractal unit 11, and three fractal units are generated with its lower right corner as the rotation center. These four fractal units together constitute the radiation structure 1. The four fractal units are set to different proportions, so that different combinations of fractal units can present a variety of results, realize flexible coverage of resonant frequencies, and multi-band millimeter-wave operation, while maintaining high radiation efficiency.

[0043] As an alternative implementation method, such as Figure 1 As shown, the original fractal unit 11 is based on a rectangle of length L and width W. The upper long side of the rectangle is divided into three equal parts, forming a first concave structure 13 in the middle, with a depth of a*W. The left wide side of the rectangle is divided into three equal parts, forming a second concave structure 14 in the middle, with a depth of a*L, thus forming a first-order Minkowski fractal structure; where a is a multiple of the concavity. Fractal structure refers to a geometric structure that possesses a certain inherent self-similarity or self-homogeneity. Self-similarity means that a small-scale geometric shape replicates the overall geometric shape at a reduced scale; self-homogeneity means that the small-scale geometric shape is not completely similar to the whole, but rather distorted and deformed, and can take different scale factors. The first-order Minkowski fractal structure is an iterative structure in fractal geometry, characterized by generating a basic shape with folds based on the initial shape through specific rules. In this embodiment, the antenna is based on the Minkowski-like original fractal unit 11. Four fractal units are generated by rotating and copying the unit with its lower right corner as the corner point. These four fractals are then independently scaled to different ratios, which is more conducive to the generation of multiple frequency points.

[0044] Furthermore, the edges of the fractal unit are not straight lines, but rather the length and width of the fractal unit are concave to form bent lines, and scaled at different ratios to reproduce a longer electrical length within the area (electrical length = physical length of the fractal unit / wavelength), enabling lower frequency resonance in the same area and reducing the antenna area at the same frequency, thus achieving antenna miniaturization.

[0045] The embodiment is merely a specific example and does not indicate that this is the only way to implement the present invention.

[0046] Example 2:

[0047] The difference between this embodiment two and embodiment one is that: Figure 2 As shown, the antenna is fabricated using SOI technology.

[0048] Specifically, such as Figure 2As shown, the antenna also includes a GSG pad 5 and a silicon substrate 6. The GSG pad 5 is disposed on the dielectric layer 3 and connected to the radiating structure 1 via a microwave transmission line 2. The two ground terminals of the GSG pad 5 are connected to the ground layer 4 via conductive lines 7. The silicon substrate 6 is located between the dielectric layer 3 and the ground layer 4, with the ground layer 4 positioned below the silicon substrate 6. Specifically, the GSG pad 5 is connected via the microwave transmission line 2, and the probe provides signal input to the radiating structure 1 through the GSG pad 5 to ensure that the antenna is fed in the SOI process. GSG (Grounded Signal Ground) is a probe connection method in radio frequency testing, mainly used for the transmission and testing of radio frequency signals. In this embodiment, the signal terminal of the GSG pad 5 is connected to the radiating structure 1 via the microwave transmission line 2, and the two ground terminals are connected to the ground layer 4 via conductive lines 7 to ensure that the GSG pad 5 and the ground layer 4 are at the same potential. Preferably, the conductive lines 7 are gold wires.

[0049] Furthermore, such as Figure 3 As shown, in the SOI process, a cross-shaped groove 15 is provided in the center of the fractal patch, and a 45° inclined groove 16 is provided in the center of the original fractal unit 11 and the three rotating fractal units 12 to optimize the frequency matching effect.

[0050] Furthermore, such as Figure 4 As shown, the radiating layer includes a first metal layer (in Figure 4 The middle layer is the metal layer TM2) and the second metal layer (in Figure 4 The first metal layer is TM; the fractal patch is disposed on the first metal layer; four L-shaped holes 17 are provided at the corners of the original fractal unit 11 and the three rotating fractal units 12 located at the rotation center, and rectangular holes 18 are provided on both sides of each inclined groove 16; metal blocks corresponding to the L-shaped holes 17 and rectangular holes 18 are disposed on the second metal layer; the metal blocks are connected to the fractal patch through conductive vias (i.e., metal vias TV1 in the figure). To mitigate the problem of excessive density concentration in the radiation structure 1, the radiation structure 1 is divided into two layers. On the first metal layer, an L-shaped hole 17 is cut at each of the four fractal units near the rotation center, and rectangular holes 18 are cut on both sides of the diagonal of the L-shaped hole 17, for a total of eight. On the second metal layer, metal blocks corresponding to the L-shaped holes 17 and rectangular holes 18 are respectively set. These metal blocks can be perfectly embedded in the L-shaped holes 17 and rectangular holes 18, and are connected to the fractal patch on the first metal layer through conductive vias (metal vias TV1). This not only alleviates the problem of excessive density concentration in the radiation structure 1, but also keeps the overall radiation structure 1 unchanged.

[0051] As an alternative implementation, the microwave transmission line 2 is a coplanar waveguide feeder disposed in the second metal layer; the central conductor 21 of the coplanar waveguide feeder is connected to the radiating structure 1; the ground plane 22 of the coplanar waveguide feeder is connected to the ground layer 4 through the conductive line 7; the ground plane 22 of the coplanar waveguide feeder is trapezoidal to optimize antenna matching and bandwidth expansion. The coplanar waveguide feeder is a microwave transmission line 2 structure consisting of a central conductor 21 and two ground planes 22 located on the same plane (usually the surface of a dielectric substrate), with the central conductor 21 separated from the two ground planes by gaps. Its main feature is that all conductor structures are in the same plane, facilitating integration with planar microwave devices (such as antennas, filters, integrated circuits, etc.). It has advantages such as compact structure, simple processing, easy impedance adjustment, and low radiation loss, and is widely used in radio frequency and microwave circuit systems as a connecting component for signal transmission and energy feeding. In this embodiment, the center conductor 21 of the coplanar waveguide feed line is used to connect the radiating structure 1 and the GSG pad 5; the ground plane 22 of the coplanar waveguide feed line is connected to the ground layer 4 through the conductive line 7 to ensure that the coplanar waveguide feed line and the GSG pad 5 are at the same potential.

[0052] As an alternative implementation, an external copper ground plane is used as ground layer 4 to improve the on-chip antenna gain. The external copper ground plane also serves as a reflector, reflecting the signal back into the air to improve radiation efficiency and antenna gain. Considering the metal density requirements in the process design rules, other metal layers within the chip (such as...) can be used instead. Figure 4 The metal dummy is filled with M1, M2 and M3 metal layers.

[0053] As an alternative implementation, the antenna in this embodiment is implemented based on a 55nm SOI process, with a silicone substrate thickness of 200µm; Figure 5 As shown, the size of the ground layer 4 is twice the size of the silicon substrate 6; the size of the silicon substrate 6 is 800um × 950um, and the size of the ground layer 4 is 1600um × 1900um; since the antenna is packaged based on the silicon substrate 6, the package size of the antenna chip is 800um × 950um.

[0054] In the 55nm SOI process implementation of this antenna, the original fractal unit 11 is based on a rectangle with a length of L = 0.3mm and a width of W = 0.18mm. The upper long side of the rectangle is divided into three equal parts, with the middle part recessed downwards to form a first recessed structure 13 with a depth of 1 / 6*W, i.e., a depth of 0.03mm. The left wide side of the rectangle is divided into three equal parts, with the middle part recessed to the right to form a second recessed structure 14 with a depth of 1 / 6*L, i.e., a depth of 0.05mm, forming a first-order Minkowski-like fractal structure. Based on this original fractal unit 11, it is rotated in 90° increments around its lower right corner to generate three rotating fractal units 12. The size ratio of these four fractal units is independently adjusted to 1:0.8:0.9:0.8, which serves as the radiation structure 1 of the on-chip antenna.

[0055] like Figure 6-8 This is a simulation diagram of the on-chip antenna implemented using a 55nm SOI process for the millimeter-wave multi-band Minkowski fractal antenna in this embodiment. The antenna impedance bandwidth is 76.3-78.4GHz and 93-100GHz, covering the 77 / 94GHz dual-band. It achieves maximum gains of 2.64dBi and 5.4dBi at 77GHz and 94GHz, respectively, with radiation efficiencies of 48% and 87%, respectively. The radiation efficiencies of both bands are >45%. Based on a chip size of 800um×950um, it not only achieves multi-band millimeter-wave operation within the chip size but also maintains a high radiation efficiency antenna.

[0056] Example 3:

[0057] The difference between this embodiment three and embodiment two is that: Figure 9 As shown, the antenna is manufactured using PCB technology.

[0058] In PCB fabrication, microwave transmission line 2 is a microstrip feeder. Microstrip feeders are characterized by their small size, light weight, and ease of integration, making them more suitable for antenna feeding in PCB fabrication.

[0059] As an alternative implementation, the dielectric layer 3 is made of Rogers RT 5880 with a thickness of 0.127 mm. Rogers RT 5880 is a high-frequency circuit board made of polytetrafluoroethylene (PTFE) glass fiber reinforced material, which has characteristics such as low dielectric constant, low loss, and low moisture absorption, making it suitable for PCB processes. A ground layer 4 is formed by fully copper-clad the lower surface of the dielectric layer 3; the copper thickness of the ground layer 4 is 22 μm.

[0060] In the PCB implementation of this antenna, the original fractal unit 11 is based on a rectangle with a length of L = 0.88 mm and a width of W = 0.6 mm. The upper long side of the rectangle is divided into three equal parts, with the middle part recessed downwards to form a first recessed structure 13 with a depth of 4 / 15 * W, i.e., a depth of 0.16 mm. The left wide side of the rectangle is divided into three equal parts, with the middle part recessed to the right to form a second recessed structure 14 with a depth of 4 / 15 * L, i.e., a depth of 3.52 / 15 mm, forming a first-order Minkowski-like fractal structure. Based on this original fractal unit 11, it is rotated in 90° increments around its lower right corner to generate three rotating fractal units 12. The size ratio of these four fractal units is independently adjusted to 1:0.63:0.9:0.5, which serves as the radiating structure 1 of the PCB antenna. The dielectric layer 3 has a thickness of 0.127 mm, the grounding layer 4 is a fully copper-clad ground plane, the material of the radiating structure 1 is copper, and the copper cladding thickness of the radiating structure 1 is 22 μm based on the upper surface of the dielectric layer 3.

[0061] like Figure 10-14 This is a simulation diagram of the millimeter-wave multi-band Minkowski fractal antenna implemented using PCB technology in this embodiment. The antenna has resonance points at 60 / 77 / 94 / 120GHz and achieves maximum gains of 6.6dBi, 7.2dBi, 5.9dBi, and 7.1dBi respectively, enabling it to operate at four frequency points.

[0062] The above description is merely a preferred embodiment of the present invention. Those skilled in the art will understand that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the present invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A millimeter-wave multi-band Minkowski-like fractal antenna, characterized in that, It includes a radiating structure (1), a microwave transmission line (2), a dielectric layer (3), and a ground layer (4); the radiating structure (1) and the microwave transmission line (2) are both disposed on the dielectric layer (3), and the microwave transmission line (2) is connected to the radiating structure (1); the ground layer (4) is disposed below the dielectric layer (3); The radiation structure (1) includes a fractal patch, which is a Minkowski-like fractal structure composed of an original fractal unit (11) and three rotating fractal units (12); the three rotating fractal units (12) are generated by rotating 90°, 180° and 270° in sequence with the corner point of the original fractal unit (11) as the reference; the original fractal unit and the three rotating fractals are not all the same or all different in size.

2. The millimeter-wave multi-band Minkowski fractal antenna according to claim 1, characterized in that, The original fractal unit (11) is based on a rectangle with length L and width W. The upper long side of the rectangle is divided into three equal parts, and a first concave structure (13) is formed in the middle. The depth of the concave structure is a*W. The left wide side of the rectangle is divided into three equal parts, and a second concave structure (14) is formed in the middle. The depth of the concave structure is a*L. This forms a first-order Minkowski fractal structure. Here, a is a multiple of the concave structure.

3. A millimeter-wave multi-band Minkowski fractal antenna according to claim 2, characterized in that, The antenna is fabricated using SOI technology; the antenna also includes a GSG pad (5) and a silicon substrate (6); the GSG pad (5) is disposed on the dielectric layer (3) and connected to the radiating structure (1) through the microwave transmission line (2); the two ground terminals of the GSG pad (5) are connected to the ground layer (4) through conductive lines (7); the silicon substrate (6) is located between the dielectric layer (3) and the ground layer (4), and the ground layer (4) is disposed below the silicon substrate (6); The thickness of the silicon substrate (6) is 200 μm; the length of the original fractal unit (11) is L = 0.3 mm, the width is W = 0.18 mm, and a = 1 / 6; the depth of the first recessed structure (13) is 0.03 mm; the depth of the second recessed structure (14) is 0.05 mm; the size ratio of the original fractal unit to the three rotating fractals is 1:0.8:0.9:0.

8.

4. A millimeter-wave multi-band Minkowski fractal antenna according to claim 3, characterized in that, The fractal patch has a cross-shaped groove (15) at its center, and a 45° oblique groove (16) is provided at the center of both the original fractal unit (11) and the three rotating fractal units (12).

5. A millimeter-wave multi-band Minkowski fractal antenna according to claim 4, characterized in that, The radiation layer includes a first metal layer and a second metal layer; the fractal patch is disposed on the first metal layer; four L-shaped holes (17) are provided at the corners of the original fractal unit (11) and the three rotating fractal units (12) located at the rotation center, and rectangular holes (18) are provided on both sides of each of the inclined grooves (16); a metal block corresponding to the L-shaped holes (17) and the rectangular holes (18) is disposed on the second metal layer; the metal block is connected to the fractal patch through a conductive via.

6. A millimeter-wave multi-band Minkowski fractal antenna according to claim 5, characterized in that, The microwave transmission line (2) is a coplanar waveguide feeder and is disposed in the second metal layer; the center guide strip (21) of the coplanar waveguide feeder is connected to the radiation structure (1); the ground plane (22) of the coplanar waveguide feeder is connected to the ground layer (4) through the conductive line (7); the ground plane (22) of the coplanar waveguide feeder is trapezoidal.

7. A millimeter-wave multi-band Minkowski fractal antenna according to claim 3, characterized in that, The size of the grounding layer (4) is twice the size of the silicon substrate (6); the size of the silicon substrate (6) is 800um×950um, and the size of the grounding layer (4) is 1600um×1900um.

8. A millimeter-wave multi-band Minkowski fractal antenna according to claim 2, characterized in that, The antenna is fabricated using PCB technology; the microwave transmission line (2) is a microstrip feed line; the length L of the original fractal unit (11) is 0.88 mm, the width W is 0.6 mm, and a is 4 / 15; the depth of the first recessed structure (13) is 0.16 mm; the depth of the second recessed structure (14) is 3.52 / 15 mm; the size ratio of the original fractal unit to the three rotating fractals is 1:0.63:0.9:0.

85.

9. A millimeter-wave multi-band Minkowski-like fractal antenna according to claim 7, characterized in that, The dielectric layer (3) is made of Rogers RT 5880 and has a thickness of 0.127 mm. The ground layer (4) is formed by covering the entire lower surface of the dielectric layer (3) with copper. The copper thickness of the ground layer (4) is 22 μm.

10. A millimeter-wave multi-band Minkowski fractal antenna according to claim 9, characterized in that, The thickness of the radiation structure (1) is 22 μm.

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