A low profile miniaturized microstrip loop antenna based on high impedance super surface loading

Abstract

This invention discloses a low-profile, miniaturized microstrip loop antenna based on a high-resistivity metasurface loading, belonging to the field of antenna technology. It includes: a bidirectional radiator; and a magnetic conductor reflector disposed on the radiating-back side of the bidirectional radiator. The magnetic conductor reflector comprises multiple periodically arranged metal patch units, each metal patch unit having a fractal edge and an internal hollow structure. The distance between the magnetic conductor reflector and the bidirectional radiator is less than half the operating wavelength of the antenna device. The magnetic conductor reflector is configured to reflect electromagnetic waves radiated in both directions by the bidirectional radiator in phase, so that the reflected waves are superimposed in phase with the forward-radiated waves. This application achieves a low profile and miniaturization of the overall antenna device.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology, specifically relating to a low-profile miniaturized microstrip loop antenna based on high-resistivity metasurface loading. Background Technology

[0002] In wireless communication and radar systems, bidirectional radiating antennas such as loop antennas are often used in miniaturized designs due to their physical size advantage. However, since these antennas inherently have bidirectional radiation characteristics, a reflector is usually required to achieve unidirectional radiation.

[0003] In traditional technologies, to achieve in-phase superposition of forward radiation and back-reflected waves, the metal reflector needs to be positioned approximately one-quarter of the operating wavelength from the radiator. This results in a relatively high overall profile of the antenna system, making it difficult to meet the ultra-thin design requirements of modern devices. Although artificial magnetic conductor (AMC) reflectors can shorten the reflection distance by utilizing in-phase reflection characteristics, the physical size of conventional AMC units is relatively large, making it difficult to compress the lateral area of ​​the reflector and limiting its application in compact spaces.

[0004] Therefore, there is an urgent need for an antenna device that can simultaneously achieve low profile and miniaturization. Summary of the Invention

[0005] In response to one or more of the above-mentioned defects or improvement needs of the prior art, the present invention provides a low-profile miniaturized microstrip loop antenna based on high-resistivity metasurface loading, which can realize the low-profile and miniaturized design of the antenna system.

[0006] To achieve the above objectives, the present invention provides a low-profile miniaturized microstrip loop antenna based on high-resistivity metasurface loading, comprising: Two-way radiator; A magnetic conductor reflector is disposed on the radiation-reverse side of the bidirectional radiator. The magnetic conductor reflector includes a plurality of periodically arranged metal patch units, each of which has a fractal edge and an internal hollow structure. The distance between the magnetic conductor reflector and the bidirectional radiator is less than half the operating wavelength of the antenna device. The magnetic conductor reflector is configured to reflect electromagnetic waves radiated in both directions by the bidirectional radiator in phase, so that the reflected waves are superimposed in phase with the forward radiated waves.

[0007] As a further preferred embodiment of the present invention, the fractal edge is a multi-level stepped extension structure.

[0008] As a further preferred embodiment of the present invention, the fractal edge is a second-order Koch fractal structure.

[0009] As a further preferred embodiment of the present invention, the internal hollow structure includes a first hollow located in the central region of the metal patch unit and / or a second hollow located on the branch arm of the fractal edge; the first hollow is a square hollow or a rectangular hollow, and the second hollow is a rectangular window.

[0010] As a further preferred embodiment of the present invention, the bidirectional radiator is a ring radiator; The magnetic conductor reflector has a planar structure and is arranged parallel to the annular radiator.

[0011] As a further preferred embodiment of the present invention, the annular radiator is an open-ring structure, the open-ring structure having an opening gap for adjusting impedance matching; The antenna device further includes a feed probe connected to the central region of the annular radiator for single-point feeding.

[0012] As a further preferred embodiment of the present invention, the plurality of metal patch units are arranged periodically in a matrix of multiple rows and columns to form the magnetic conductor reflector.

[0013] As a further preferred embodiment of the present invention, the magnetic conductor reflector further includes a dielectric substrate and a metal layer covering the surface of the dielectric substrate; The plurality of metal patch units are formed by etching the metal layer.

[0014] As a further preferred embodiment of the present invention, the dielectric constant of the dielectric substrate is greater than or equal to 10.

[0015] As a further preferred embodiment of the present invention, the magnetic conductor reflector is a modular unit, and multiple magnetic conductor reflectors are spliced ​​together to form an array of reflective surfaces.

[0016] In summary, the beneficial effects of the above-described technical solutions conceived by this invention compared with the prior art include: This invention relates to a low-profile miniaturized microstrip loop antenna based on high-resistivity metasurface loading. It utilizes a magnetic conductor reflector constructed from metal patch units with fractal edges and internal hollow structures. The fractal edges extend the surface current path to increase the electrical length, while the internal hollow structure adjusts the equivalent capacitance and impedance of the unit. These two factors work synergistically to significantly reduce the resonant frequency of the unit while maintaining in-phase reflection characteristics, thereby greatly reducing the lateral physical size of the reflector unit while ensuring performance. Furthermore, by utilizing the in-phase reflection characteristics of the magnetic conductor reflector, electromagnetic waves radiated in opposite directions from the bidirectional radiator are reflected and superimposed in phase with the forward-radiated wave. This allows the distance between the reflector and the radiator to be less than half the operating wavelength, breaking the limitation of traditional metal reflectors requiring a quarter-wavelength spacing. Ultimately, this achieves a low profile and miniaturization of the overall antenna device, solving the technical problems of high antenna profile and large lateral size in existing technologies. Attached Figure Description

[0017] Figure 1 This is an overall structural diagram of a low-profile miniaturized microstrip loop antenna based on high-resistivity metasurface loading in an embodiment of the present invention; Figure 2 This is a diagram of the ring radiator structure of a low-profile miniaturized microstrip ring antenna based on high-resistivity metasurface loading in an embodiment of the present invention. Figure 3 This is a structural diagram of a low-profile miniaturized microstrip loop antenna bidirectional radiator based on high-resistivity metasurface loading in an embodiment of the present invention; Figure 4 It is a typical 2nd order Koch fractal pattern; Figure 5 This is a 2nd-order Koch fractal pattern of this application; Figure 6 This is a frequency comparison diagram of the low-profile miniaturized microstrip loop antenna metal patch based on high-resistivity metasurface loading and a general second-order Koch fractal pattern under the same structure in the embodiments of the present invention. Figure 7 The standing wave ratio (SWR) of the low-profile miniaturized microstrip loop antenna based on high-resistivity metasurface loading in this embodiment of the invention is the result of simulation. Figure 8 This is the simulated radiation pattern of a low-profile miniaturized microstrip loop antenna based on high-resistivity metasurface loading in an embodiment of the present invention.

[0018] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: 1. Bidirectional radiator; 2. Ring radiator; 3. Magnetic conductor reflector; 4. Metal patch unit; 5. Dielectric substrate; 6. First cutout; 7. Second cutout. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0020] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0022] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0023] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0024] Example: Please see Figures 1-8 The low-profile miniaturized microstrip loop antenna based on high-resistivity metasurface loading in the preferred embodiment of the present invention can realize the low-profile and miniaturized design of the antenna system.

[0025] It's just a matter of specifics, such as... Figure 1 As shown in the preferred embodiment of this application, the antenna includes a bidirectional radiator 1 and a magnetic conductor reflector 3.

[0026] In this embodiment, the bidirectional radiator 1 serves as the excitation source for electromagnetic waves. Its inherent radiation characteristics manifest as simultaneously radiating energy in both the forward and backward directions in space. For example, it can be a loop antenna, a dipole antenna, or other radiator structure with a bidirectional radiation mode. This embodiment does not specifically limit this. The magnetic conductor reflector 3 is disposed on the backward side of the bidirectional radiator 1 to regulate the propagation characteristics of the backward radiation wave.

[0027] Furthermore, the magnetic conductor reflector 3 includes a plurality of periodically arranged metal patch units 4, each metal patch unit 4 having a fractal edge and an internal hollow structure.

[0028] The fractal edge, through self-similar iteration or tortuous extension of its geometric shape, can significantly extend the current flow path within a limited physical area, thereby introducing a larger equivalent inductance. Meanwhile, the internal hollow structure effectively adjusts the equivalent capacitance of the unit by altering the charge distribution area of ​​the metal patch. The synergistic effect of the fractal edge and the internal hollow structure allows the metal patch unit 4 to reduce the LC resonant frequency to the target operating frequency band while maintaining a small physical size. This is the key physical mechanism for achieving miniaturization of the reflector's lateral dimensions. Furthermore, in a preferred embodiment of this application, the distance between the magnetic conductor reflector 3 and the bidirectional radiator 1 is less than half the operating wavelength of the antenna device.

[0029] The magnetic conductor reflector 3 is configured to reflect electromagnetic waves radiated in both directions by the bidirectional radiator 1 in phase, so that the reflected wave is superimposed in phase with the forward-radiated wave. Specifically, when the backward electromagnetic wave is incident on the surface of the magnetic conductor reflector 3, due to its special impedance characteristics, the phase of the reflection coefficient is close to 0 degrees near the resonant frequency, rather than the 180 degrees of a traditional metallic conductor. This means that the reflected wave remains in phase with the incident wave as it leaves the reflector surface, without needing to rely on a quarter-wavelength propagation path to compensate for the 180-degree phase difference as in traditional designs. Therefore, even if the magnetic conductor reflector 3 is placed close to the bidirectional radiator 1 (requiring only necessary mechanical support or non-radiating gaps), the reflected electromagnetic wave can still achieve constructive interference with the forward-radiated electromagnetic wave of the bidirectional radiator 1 in space, thereby greatly reducing the overall profile height of the antenna device while ensuring the unidirectional radiation gain of the antenna.

[0030] Further preferably, in the preferred embodiment of this application, the fractal edge is a multi-level stepped extension structure. Specifically, this multi-level stepped extension structure is not a simple straight-line bend, but a self-similar geometric contour formed through multiple iterations, which can maximize the extension of the surface current flow path within a limited physical area, thereby significantly increasing the equivalent inductance of the unit. Simultaneously, the internal hollow structure includes a first hollow 6 located in the central region of the metal patch unit 4 and / or a second hollow 7 located on the branch arm of the fractal edge. Here, the first hollow 6 and the second hollow 7 serve to adjust the equivalent capacitance electromagnetically.

[0031] When electromagnetic waves are incident, the hollowed-out area changes the charge distribution density on the surface of the metal patch, causing the parameters of the overall LC resonant circuit of the unit to shift.

[0032] More specifically, in the preferred embodiment of this application, the shape edge is specifically a second-order Koch fractal structure. A Koch fractal is a classic space-filling curve, and the second-order iteration provides sufficient edge length while ensuring processing accuracy. Based on this, the first cutout 6 is a square or rectangular cutout, and the second cutout 7 is a rectangular window. To more clearly illustrate the miniaturization mechanism of this specific combination, a comparative analysis is provided below with reference to the accompanying drawings.

[0033] like Figure 4 As shown, in existing technologies, typical second-order Koch fractal patterns primarily rely on the tortuous extension of the edges to reduce the frequency, while the internal metallic regions remain intact and solid. However, as... Figure 5 As shown, this embodiment retains the edge features of a second-order Koch fractal while creating a square first cutout 6 at the center of the unit and rectangular second cutouts 7 at the ends of the branch arms and at the turning points. This improved structure introduces additional edge effects and gap capacitance, which is equivalent to adding an additional capacitive load in parallel on top of the original inductive load, thereby further reducing the resonant frequency of the unit.

[0034] Furthermore, in the preferred embodiment of this application, Figure 6 The diagram shows a comparison of the reflection phase frequency curves of embodiments of this application and a typical second-order Koch fractal structure in the prior art under the same physical dimensions. Figure 6 It can be seen that, when the unit dimensions are exactly the same, the following approach is adopted: Figure 4 The reflector shown has a typical second-order Koch fractal structure with a phase-to-frequency (RTF) point (i.e., zero-phase point) of approximately 1.63 GHz; while using... Figure 5The improved reflector structure shown in this application has its in-phase and out-of-phase radio frequency points shifted to 1.55 GHz, with a frequency difference of 80 MHz. This significant frequency redshift phenomenon strongly demonstrates that the synergistic effect of the internal hollow structure and fractal edges can effectively reduce the operating frequency. In other words, to operate in the same 1.55 GHz band, the metal patch unit 4 of this application can adopt a smaller physical size than the traditional second-order Koch unit, thereby achieving a substantial reduction in the size of the magnetic conductor reflector unit 3 while ensuring the in-phase reflection bandwidth and performance indicators, and solving the technical problem of excessively large lateral area of ​​traditional AMC reflectors.

[0035] More preferably, in the preferred embodiment of this application, the bidirectional radiator 1 is specifically an annular radiator 2, and the magnetic conductor reflector 3 has a planar structure and is arranged parallel to the annular radiator 2.

[0036] More specifically, in the preferred embodiments of this application, such as Figure 1 As shown, the ring radiator 2 is located directly above the magnetic conductor reflector 3, with a preset subwavelength spacing between them. The ring structure was chosen as the bidirectional radiator 1 because the ring antenna naturally possesses bidirectional radiation characteristics perpendicular to the ring surface in its operating mode, which is highly compatible with the in-phase reflection control mechanism of the magnetic conductor reflector 3. Simultaneously, setting the magnetic conductor reflector 3 as a planar structure and strictly parallel to the ring radiator 2 ensures that the incident angle distribution of the back-radiated wave on the reflector surface is relatively concentrated and symmetrical, thereby guaranteeing the uniformity and stability of the reflected phase and avoiding beam deflection or gain loss caused by tilted or non-parallel placement.

[0037] Furthermore, in a preferred embodiment of this application, in order to optimize the impedance matching performance of the antenna, the annular radiator 2 is preferably an open-ring structure having an opening gap for adjusting impedance matching.

[0038] Further preferably, in the preferred embodiments of this application, such as Figure 2 As shown, the opening gap breaks the originally closed metal ring, forming a series equivalent capacitor. By precisely adjusting the size of the opening gap (i.e., the opening angle or the gap width), the capacitance value of this equivalent capacitor can be continuously changed, thereby fine-tuning the input impedance of the ring radiator 2 to achieve a good match with the feeder system within the target operating frequency band, without the need for an additional complex matching network.

[0039] More specifically, in the preferred embodiment of this application, the outer diameter of the annular radiator 2 can be set to 13 mm, and the opening angle corresponding to the opening gap can be set to 25°. These parameters can be flexibly adjusted according to the actual operating frequency and the dielectric constant of the substrate. Furthermore, the antenna device also includes a feed probe connected to the central region of the annular radiator 2 for single-point feeding. This central single-point feeding method utilizes the electric field symmetry of the annular radiator 2 during fundamental mode operation, effectively suppressing the excitation of higher-order modes and ensuring the purity of the radiation pattern. Compared to traditional edge feeding or coupled feeding, the central feeding structure is more compact and does not disrupt the near-field coupling environment between the annular radiator 2 and the underlying magnetic conductor reflector 3, which is beneficial for maintaining the overall low profile characteristics. In specific implementation, the feed probe can be the inner core of a coaxial cable, passing through the dielectric substrate 5 and directly connected to the central pad of the annular radiator 2, while the outer conductor is grounded or connected to the reflector ground layer.

[0040] Furthermore, in a preferred embodiment of this application, multiple metal patch units 4 are periodically arranged in a matrix of multiple rows and columns to form a magnetic conductor reflector 3.

[0041] like Figure 3 As shown, in this embodiment, the metal patch units 4 are arranged in a 2x3 matrix to form a rectangular reflective surface. This periodic matrix arrangement is the physical basis for the equivalent surface impedance characteristics of artificial magnetic conductors. Only when the unit size is much smaller than the operating wavelength and exhibits strict periodicity can the discrete metal patch array be macroscopically equivalent to a uniform electromagnetic boundary, thereby achieving continuous modulation of the phase of the incident electromagnetic wave. If the arrangement lacks periodicity or the unit spacing is too large, it may lead to the generation of grating lobes or a sharp narrowing of the in-phase reflection bandwidth, failing to meet the design requirements of broadband low profile.

[0042] It should be noted that the 2×3 arrangement is merely an example provided to meet the miniaturization requirements of a specific application scenario. In actual engineering, the arrangement can be expanded to 4×4, 8×8, or even larger arrays, depending on the antenna gain requirements and installation space, or other periodic arrangements such as triangles or hexagons can be used. As long as the electromagnetic response characteristics of the artificial magnetic conductor can be maintained, they all fall within the scope of protection of this application. In a specific prototype verification, when an antenna device with the above-mentioned 2×3 arrangement, unit size of 20mm×20mm, and a total height of only 3.5mm (approximately 7.6% of the theoretical height) was tested, it still achieved a gain of 5.66dB and a VSWR bandwidth that meets the application requirements, fully demonstrating the effectiveness of this physical implementation scheme under extreme miniaturization conditions.

[0043] More preferably, in a preferred embodiment of this application, the magnetic conductor reflector 3 further includes a dielectric substrate 5 and a metal layer covering the surface of the dielectric substrate 5.

[0044] More specifically, in the preferred embodiment of this application, the dielectric substrate 5 serves as a support carrier, providing a dielectric environment with mechanical strength and electromagnetic field distribution for the metal layer. The metal layer is typically made of copper foil, aluminum foil, or other highly conductive metal materials, and a preset metal patch unit 4 pattern is formed on the surface of the dielectric substrate 5 through planar processes such as photolithography, chemical etching, or laser processing.

[0045] Furthermore, in a preferred embodiment of this application, the dielectric constant of the dielectric substrate 5 is greater than or equal to 10. This material parameter is not arbitrarily chosen, but rather based on the physical laws governing the propagation of electromagnetic waves in a dielectric. According to electromagnetic field theory, the effective wavelength of an electromagnetic wave in a dielectric is inversely proportional to the square root of the dielectric's relative permittivity. When the dielectric substrate 5 uses a material with a high dielectric constant, the operating wavelength can be significantly compressed, allowing the physical size of the metal patch unit 4 to be proportionally reduced while maintaining the same electrical length (i.e., the same resonant frequency).

[0046] This "wavelength compression effect" caused by material properties, combined with the "geometric path extension effect" achieved through fractal edges and internal hollowing, constitutes the "dual miniaturization" mechanism of the antenna device of this application.

[0047] Furthermore, in a specific verification prototype, the dielectric substrate 5 is a high-frequency ceramic substrate with a dielectric constant of 16 and a thickness of 1.5 mm. Under this parameter configuration, the unit size of the magnetic conductor reflector 3 can be further reduced, while maintaining good in-phase reflection bandwidth and structural stability.

[0048] It should be noted that a dielectric constant of 16 is only a preferred example. In practical applications, dielectric constants of 10, 12, 20, or even higher can be flexibly selected from ceramic-filled polytetrafluoroethylene composite materials, alumina ceramics, or barium titanate-based dielectric materials, depending on the target frequency band, loss tangent requirements, and cost budget. Furthermore, the thickness of the dielectric substrate 5 is not limited to 1.5 mm; adjustments within the range of 0.5 mm to 3 mm can achieve the desired technical effect. The choice of thickness mainly depends on the required quality factor and mechanical strength balance.

[0049] More preferably, in the preferred embodiment of this application, the magnetic conductor reflector 3 is a splicable unit, and multiple magnetic conductor reflectors 3 are spliced ​​together to form an array reflective surface.

[0050] Specifically, since the metal patch units 4 on the surface of the magnetic conductor reflector 3 are inherently designed based on a periodic arrangement, the electromagnetic boundary conditions at their edges possess natural continuity. Therefore, a single magnetic conductor reflector 3 can be considered a standardized basic module. Multiple modules can be seamlessly spliced ​​horizontally using mechanical snap-fit, adhesive, or screw fixing methods to construct a large-area array reflector of arbitrary size. This modular splicing design not only breaks through the limitations of single substrate processing size, making the manufacturing of ultra-large aperture reflectors possible, but also greatly improves production yield and transportation convenience. When applied to scenarios such as large-scale array radar or mobile communication base stations, this spliced ​​array reflector can effectively replace traditional monolithic metal reflectors, solving engineering problems such as excessively high profiles and excessive wind resistance in large antenna systems while maintaining excellent electromagnetic reflection performance. It should be understood that the splicing method is not limited to two-dimensional expansion in a plane; flexible splicing or conformal installation can also be performed according to the curvature of the carrier surface, as long as the spacing between adjacent units meets the periodic requirements.

[0051] To verify the effectiveness of the technical solution of this application in practical applications, a comprehensive electromagnetic performance test was conducted on the antenna device configured with the parameters described in the above specific embodiments.

[0052] Figure 7 The VSWR (Standing Wave Ratio) test curve of this antenna device is shown. Figure 7 It can be seen that within the operating frequency band, the voltage standing wave ratio (VSWR) of the antenna device remains at a low level, indicating that good impedance matching is achieved between the ring radiator 2 and the magnetic conductor reflector 3, and the introduction of subwavelength spacing does not lead to serious mismatch loss, thus ensuring sufficient effective operating bandwidth.

[0053] Figure 8 The gain pattern of the antenna device is shown. Test results show that under extremely low profile conditions with a total height of only 3.5 mm (approximately 7.6% of the theoretical height of a quarter wavelength), the antenna device still achieves a peak gain of 5.66 dB, and the radiation pattern exhibits good symmetry and directivity. Back radiation is effectively suppressed, proving that the in-phase reflection mechanism of the magnetic conductor reflector 3 plays a substantial role in the near-field region.

[0054] This result strongly confirms that the proposed solution has successfully broken through the technical bottleneck of the difficulty in achieving both "low profile" and "high gain" in traditional antenna design. While achieving an extremely compact structure, it maintains or even surpasses the radiation performance of traditional antennas of the same size, providing a practical and feasible technical path for the lightweight and integrated development of modern wireless communication equipment and radar systems.

[0055] The low-profile miniaturized microstrip loop antenna based on high-resistivity metasurface loading in this invention utilizes a metal patch unit 4 with fractal edges and an internal hollow structure to construct a magnetic conductor reflector 3. The fractal edges extend the surface current path to increase the electrical length, while the internal hollow structure adjusts the equivalent capacitance and impedance of the unit. These two factors work synergistically to significantly reduce the resonant frequency of the unit while maintaining in-phase reflection characteristics, thereby greatly reducing the lateral physical size of the reflector unit while ensuring performance. Furthermore, by utilizing the in-phase reflection characteristics of the magnetic conductor reflector 3, electromagnetic waves radiated in opposite directions by the bidirectional radiator 1 are reflected and superimposed in phase with the forward-radiated wave. This allows the distance between the reflector and the radiator to be less than half the operating wavelength, breaking the limitation of traditional metal reflectors requiring a quarter-wavelength distance. Ultimately, this achieves a low profile and miniaturization of the overall antenna device, solving the technical problems of high antenna profile and large lateral size in existing technologies.

[0056] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A low-profile miniaturized microstrip loop antenna based on high-resistivity metasurface loading, characterized in that, include: Two-way radiator; A magnetic conductor reflector is disposed on the radiation-reverse side of the bidirectional radiator. The magnetic conductor reflector includes a plurality of periodically arranged metal patch units, each of which has a fractal edge and an internal hollow structure. The distance between the magnetic conductor reflector and the bidirectional radiator is less than half the operating wavelength of the antenna device. The magnetic conductor reflector is configured to reflect electromagnetic waves radiated in both directions by the bidirectional radiator in phase, so that the reflected waves are superimposed in phase with the forward radiated waves.

2. The low-profile miniaturized microstrip loop antenna based on high-resistivity metasurface loading according to claim 1, characterized in that, The fractal edge is a multi-level stepped extension structure.

3. The low-profile miniaturized microstrip loop antenna based on high-resistivity metasurface loading according to claim 2, characterized in that, The fractal edge is a second-order Koch fractal structure.

4. The low-profile miniaturized microstrip loop antenna based on high-resistivity metasurface loading according to any one of claims 1 to 3, characterized in that, The internal hollow structure includes a first hollow located in the central region of the metal patch unit and / or a second hollow located on the branch arm of the fractal edge; the first hollow is a square hollow or a rectangular hollow, and the second hollow is a rectangular window.

5. The low-profile miniaturized microstrip loop antenna based on high-resistivity metasurface loading according to any one of claims 1 to 3, characterized in that, The bidirectional radiator is a ring radiator; The magnetic conductor reflector has a planar structure and is arranged parallel to the annular radiator.

6. The low-profile miniaturized microstrip loop antenna based on high-resistivity metasurface loading according to claim 5, characterized in that, The annular radiator is an open-ring structure, and the open-ring structure has an opening gap for adjusting impedance matching; The antenna device further includes a feed probe connected to the central region of the annular radiator for single-point feeding.

7. The low-profile miniaturized microstrip loop antenna based on high-resistivity metasurface loading according to claim 5, characterized in that, The multiple metal patch units are arranged periodically in a matrix of multiple rows and columns to form the magnetic conductor reflector.

8. The low-profile miniaturized microstrip loop antenna based on high-resistivity metasurface loading according to any one of claims 1 to 3, characterized in that, The magnetic conductor reflector also includes a dielectric substrate and a metal layer covering the surface of the dielectric substrate; The plurality of metal patch units are formed by etching the metal layer.

9. The low-profile miniaturized microstrip loop antenna based on high-resistivity metasurface loading according to claim 8, characterized in that, The dielectric constant of the dielectric substrate is greater than or equal to 10.

10. The low-profile miniaturized microstrip loop antenna based on high-resistivity metasurface loading according to any one of claims 1 to 3, characterized in that, The magnetic conductor reflector is a modular unit, and multiple magnetic conductor reflectors can be spliced ​​together to form an array of reflective surfaces.

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