Artificial magnetic conductor reflector applied to communication frequency band and low-profile dual-frequency antenna

Abstract

The application relates to a man-made magnetic conductor reflector applied to a communication frequency band and a low-profile double-frequency antenna, and relates to the technical field of microwave antennas. The application is to solve the problem that a traditional AMC structure is difficult to meet the demand of multi-frequency band collaborative work. The man-made magnetic conductor reflector applied to the communication frequency band is composed of a plurality of double-frequency AMC units arranged in a rectangular array; the double-frequency AMC unit comprises an FR4 dielectric substrate, and a metal patch and a metal reflection plate located on the two sides of the FR4 dielectric substrate; the man-made magnetic conductor reflector can excite two independent in-phase reflection phase band gaps; the low-profile double-frequency antenna comprises the man-made magnetic conductor reflector and a double-frequency antenna radiation unit located above the man-made magnetic conductor reflector; the two are separated by air medium or a low-dielectric-constant support, forming a low-profile structure. The distance between the two is 0.5 lambda, wherein lambda is the free space wavelength corresponding to the center frequency 2.55 GHz.

Description

Technical Field

[0001] This application belongs to the field of microwave antenna technology. Background Technology

[0002] With the popularization of fifth-generation mobile communication (5G) technology, terminal devices have placed higher demands on antenna performance. In particular, achieving multi-band, low profile, high port isolation and stable radiation characteristics within limited equipment space has become a key technical challenge in the industry.

[0003] Traditional microstrip antennas typically suffer from high profile, severe inter-port coupling, and pattern distortion in highly integrated environments. Artificial magnetic conductors (AMCs) are widely used to reduce antenna profile due to their unique in-phase reflection characteristics. However, traditional AMC structures (such as square or circular patches) can usually only achieve in-phase reflection within a single frequency band, making it difficult to meet the requirements of modern communication systems for multi-band collaborative operation. Summary of the Invention

[0004] This application addresses the problem that traditional AMC structures cannot meet the requirements of multi-band collaborative operation, and provides an artificial magnetic conductor reflector and a low-profile dual-band antenna for communication bands. This application employs a novel dual-band AMC reflector that can simultaneously achieve low profile, high gain, high port isolation, and a stable radiation pattern in two discontinuous frequency bands (covering 4G / 5G N78 and other bands), making it suitable for low-profile, high-isolation dual-band antenna structures in 4G / 5G communication systems.

[0005] The first aspect of this application provides an artificial magnetic conductor reflector for use in communication frequency bands, comprising: a plurality of dual-frequency AMC units arranged in a rectangular array;

[0006] The dual-frequency AMC unit includes: an FR4 dielectric substrate, and metal patches and metal reflectors located on both sides of the FR4 dielectric substrate;

[0007] The artificial magnetic conductor reflector can excite two independent in-phase reflection phase band gaps.

[0008] In one possible design, the FR4 dielectric substrate has a dielectric constant of 4.4, a loss tangent of 0.02, and a thickness of 3 mm.

[0009] In one possible design, the metal patch is circular, and concentric rings are etched on the metal patch.

[0010] In one possible design, the metal patch has a radius of 13 mm, and the inner ring radius of the concentric rings is 11 mm.

[0011] In one possible design, the artificial magnetic conductor reflector is able to achieve in-phase reflection characteristics in the 2.05GHz~2.14GHz and 3.3GHz~3.6GHz frequency bands, with a reflection phase between ±90°.

[0012] The second aspect of this application provides a low-profile dual-frequency antenna based on the aforementioned artificial magnetic conductor reflector used in communication frequency bands, comprising: an artificial magnetic conductor reflector and a dual-frequency antenna radiating element;

[0013] The dual-frequency antenna radiating element is located above the artificial magnetic conductor reflector and is separated from the artificial magnetic conductor reflector by an air medium or a low dielectric constant support, forming a low profile structure.

[0014] The distance between the dual-frequency antenna radiating element and the artificial magnetic conductor reflector is: , The free space wavelength corresponds to a center frequency of 2.55 GHz.

[0015] In one possible design, the dual-frequency antenna radiating element is supported by a plastic support column to the artificial magnetic conductor reflector.

[0016] In one possible design, the distance between the dual-frequency antenna radiating element and the artificial magnetic conductor reflector is 11 mm.

[0017] In one possible design, the dual-band antenna radiating element includes: a dielectric substrate, a pair of orthogonal butterfly dipoles located on one side of the dielectric substrate, and four T-shaped parasitic stubs located on the other side of the dielectric substrate.

[0018] In one possible design, the thickness of the substrate is 0.5 mm, and the arm length of the butterfly dipole is 24 mm.

[0019] The beneficial effects of this application are:

[0020] 1. True dual-frequency AMC design: Through a simple "ring slot on a circular patch" structure, dual-frequency in-phase reflection is achieved, solving the problem that traditional AMCs can only be used for a single frequency band. The structure is simple, requiring no complex active circuits or multi-layer structures, and is easy to process and manufacture.

[0021] 2. Extremely low profile: The overall profile height of the antenna is only 0.08λ0, which greatly saves equipment space and is very suitable for modern mobile terminals and base station equipment with strict thickness requirements.

[0022] 3. High port isolation: Polarization diversity is achieved by using a pair of orthogonal butterfly dipoles. Combined with overall structural optimization, the isolation of the two feed ports in both frequency bands is better than 25dB, which effectively reduces inter-channel interference and is suitable for MIMO systems.

[0023] 4. Excellent radiation performance: The antenna achieves good impedance matching (return loss < -10dB), high gain (peak gain up to 6.91dBi), and stable directional radiation pattern in both operating frequency bands, with a cross-polarization ratio better than 25dB, ensuring communication quality. Attached Figure Description

[0024] Figure 1 A comparison diagram of the current distribution of the AMC structure before and after slotting at different frequencies;

[0025] Figure 2 This is a schematic diagram of the structure of a dual-frequency AMC unit, where (a) represents a three-dimensional view and (b) represents a front view;

[0026] Figure 3 The reflection characteristic curve of the dual-frequency AMC unit is shown.

[0027] Figure 4 This is a schematic diagram of a low-profile dual-frequency antenna.

[0028] Figure 5 This is a front view of a low-profile dual-band antenna.

[0029] Figure 6 The diagram shows the dimensions of the main radiator and parasitic elements of a low-profile dual-frequency antenna.

[0030] Figure 7 Dimensional parameters of the feed balun structure for a low-profile dual-frequency antenna;

[0031] Figure 8 The S-parameter curves of the antenna element;

[0032] Figure 9 This is a gain curve diagram of the antenna element;

[0033] Figure 10 Normalized radiation patterns of the main polarization and cross-polarization of antennas at different frequencies are shown, where (a) E-plane, 2.2 GHz; (b) H-plane, 2.2 GHz; (c) E-plane, 3.4 GHz; (d) H-plane, 3.4 GHz.

[0034] In the figure, 1 is the FR4 dielectric substrate, 2 is the metal patch, and 3 is the metal reflector. Detailed Implementation

[0035] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0036] While existing technologies employ methods such as loading resonant rings, reconfigurable techniques, or frequency selective surfaces (FSS) to extend AMC performance or achieve dual-frequency operation, these solutions often result in complex structures, high fabrication difficulty, or high costs. For example, while introducing active devices such as PIN diodes can achieve reconfigurability, it increases control circuitry and power consumption.

[0037] In view of this, the embodiments of this application provide an artificial magnetic conductor reflector and a low-profile dual-band antenna for use in communication frequency bands, in order to solve the above-mentioned problems. The following will be described in conjunction with the accompanying drawings. Figures 1 to 7 The implementation scheme of this application will be described in detail.

[0038] Specific implementation method one: an artificial magnetic conductor reflector applied to the communication frequency band, including: several dual-frequency AMC units arranged in a rectangular array.

[0039] like Figure 2 As shown, the dual-frequency AMC unit includes: an FR4 dielectric substrate 1, and metal patches 2 and metal reflectors 3 located on both sides of the FR4 dielectric substrate 1.

[0040] Metal patch 2 is circular with a radius R1 of 13 mm. Concentric rings are etched on metal patch 2, with the inner ring having a radius R2 of 11 mm. (Example:) Figure 1 As shown, an annular groove is formed on the metal patch 2 by etching, disturbing the surface current distribution, thereby exciting two independent in-phase reflection phase bandgap in the dual-band AMC unit, corresponding to the two operating frequency bands required by the antenna. Figure 3 As shown, through optimization using simulation software (such as CST or HFSS), in-phase reflection (reflection phase between ±90°) characteristics were finally obtained in the 2.05-2.14GHz and 3.3-3.6GHz frequency bands.

[0041] Dielectric constant of FR4 dielectric substrate 1 Loss tangent The thickness is 3mm.

[0042] This implementation achieves dual-frequency in-phase reflection through a passive structure of "etching a concentric annular groove on a circular patch." All structures can be fabricated on a single-layer FR4 dielectric substrate without any active components or additional processing steps, resulting in a simpler structure and significantly reduced cost. The two in-phase reflection bandgap generated by the AMC unit (2.05-2.14GHz and 3.3-3.6GHz) cover the 4G low-frequency band and the 5G band, respectively, meeting the practical application requirements of current mobile communication systems. Simultaneously, the parameters of the annular groove (inner radius, ring width) can be independently tuned to the high-frequency AMC bandgap, while the low-frequency bandgap is mainly determined by the overall size of the circular patch. The in-phase reflection frequencies of the two bands can be adjusted relatively independently, offering high design flexibility and facilitating rapid customization for different application scenarios.

[0043] Specific implementation method two: The low profile dual-frequency antenna described in this implementation method includes: a dual-frequency circular AMC reflector, a dual-frequency antenna radiating element, and a feed balun structure.

[0044] like Figure 4 As shown, the dual-frequency antenna radiating element is located above the dual-frequency circular AMC reflector described in Embodiment 1, and is separated from the dual-frequency circular AMC reflector by an air medium or a low-dielectric-constant support, forming a low-profile structure. The distance between the dual-frequency antenna radiating element and the dual-frequency circular AMC reflector is... ,in The wavelength in free space corresponds to a center frequency of 2.55 GHz. In this embodiment, the dual-frequency antenna radiating element and the lower dual-frequency circular AMC reflector are supported by plastic pillars with a spacing of 11 mm, which is approximately 0.08 times the wavelength corresponding to the center frequency of 2.55 GHz.

[0045] The dual-band antenna radiating element comprises: a pair of orthogonal butterfly dipoles, a dielectric substrate, and four T-shaped parasitic stubs. The dielectric substrate is an FR4 dielectric substrate with a thickness of 0.5 mm. A pair of orthogonally arranged butterfly dipoles are etched on the upper surface of the dielectric substrate to generate radiation and achieve polarization diversity, thereby naturally improving the isolation between the two ports. The arm length of the butterfly dipoles is 24 mm. Four T-shaped parasitic stubs are etched on the lower surface of the dielectric substrate. These parasitic stubs are coupled to the upper butterfly dipoles to introduce and control the high-frequency resonant point, thereby enabling the antenna to operate on two frequencies: 2.11 GHz to 2.31 GHz and 3.35 GHz to 3.58 GHz.

[0046] The feed balun structure adopts The microstrip balun is connected to a pair of orthogonal butterfly dipoles to achieve unbalanced-to-balanced switching and to feed the two polarization ports.

[0047] Table 1 Antenna Structure Dimensions Comparison Table

[0048]

[0049] refer to Figures 8 to 10 Simulation results show that this implementation method performs excellently in both target frequency bands:

[0050] The port return loss is less than -10dB, the port isolation is greater than 25dB, the peak gain reaches 6.91dBi, and the radiation pattern is stable with good front-to-back ratio and low cross-polarization level.

[0051] While specific embodiments of this application have been described herein with reference to them, it should be understood that these embodiments are merely examples of the principles and applications of this application. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of this application as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. Artificial magnetic conductor reflector applied to a communication frequency band, characterized in that, include: Several dual-frequency AMC units arranged in a rectangular array; The dual-frequency AMC unit includes: an FR4 dielectric substrate, and metal patches and metal reflectors located on both sides of the FR4 dielectric substrate; The artificial magnetic conductor reflector can excite two independent in-phase reflection phase band gaps.

2. AMC reflector for use in a communication frequency band according to claim 1, characterized in that, The FR4 dielectric substrate has a dielectric constant of 4.4, a loss tangent of 0.02, and a thickness of 3 mm.

3. AMC reflector for use in a communication frequency band according to claim 1 or 2, characterized in that, The metal patch is circular, and concentric rings are etched on the metal patch.

4. AMC reflector for use in a communication frequency band according to claim 3, characterized in that, The radius of the metal patch is 13mm, and the inner radius of the concentric ring is 11mm.

5. The AMC reflector for communication bands as claimed in claim 1, wherein, The artificial magnetic conductor reflector can achieve in-phase reflection characteristics in the frequency bands of 2.05GHz~2.14GHz and 3.3GHz~3.6GHz, with a reflection phase between ±90°.

6. The low-profile dual-band antenna using the AMC reflector for the communication frequency band according to any one of claims 1 to 5, characterized in that, include: Artificial magnetic conductor reflector and dual-band antenna radiating element; The dual-frequency antenna radiating element is located above the artificial magnetic conductor reflector and is separated from the artificial magnetic conductor reflector by an air medium or a low dielectric constant support, forming a low profile structure. The distance between the dual-frequency antenna radiation unit and the artificial magnetic conductor reflector is , is the free space wavelength corresponding to the center frequency 2.55 GHz.

7. The low-profile dual-band antenna according to claim 6, wherein The dual-frequency antenna radiating element and the artificial magnetic conductor reflector are supported by a plastic support column.

8. The low-profile dual-frequency antenna according to claim 6 or 7, characterized in that, The distance between the dual-frequency antenna radiating element and the artificial magnetic conductor reflector is 11 mm.

9. The low-profile dual-frequency antenna according to claim 6, characterized in that, The dual-frequency antenna radiating element includes: a dielectric substrate, a pair of orthogonal butterfly dipoles located on one side of the dielectric substrate, and four T-shaped parasitic stubs located on the other side of the dielectric substrate.

10. The low-profile dual-frequency antenna according to claim 9, characterized in that, The thickness of the substrate is 0.5 mm, and the arm length of the butterfly dipole is 24 mm.

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