Low-profile multi-band microstrip antenna based on inverted-T-shaped-H-shaped groove composite structure

Abstract

The utility model belongs to the technical field of antenna communication, and particularly relates to a low-profile multi-band microstrip antenna based on an inverted-T-shaped-H-shaped groove composite structure, which comprises a top-layer radiation metal plate, a middle-layer dielectric substrate, a bottom-layer grounding metal plate and a coaxial line, and is characterized in that the top-layer radiation metal plate comprises an inverted-T-shaped patch; an H-shaped through groove is formed in the convex patch, the H-shaped through groove is located in the right side of the convex patch, the H-shaped through groove is formed by communicating a pair of parallel transverse grooves and a longitudinal groove, and the top-layer radiation metal plate, the middle-layer dielectric substrate and the bottom-layer grounding metal plate are sequentially arranged in a stacked mode from top to bottom. And the coaxial line penetrates through the top-layer radiation metal plate, the middle-layer dielectric substrate and the bottom-layer grounding metal plate. The top-layer radiation metal plate comprises the convex patch, the H-shaped through groove is formed in the convex patch, and multi-frequency-band work is achieved on the middle-layer dielectric substrate, so that the compact size is kept, and the complex structure of a traditional stacked antenna is avoided.

Description

Technical Field

[0001] This utility model belongs to the field of antenna communication technology, specifically relating to a low-profile multi-band microstrip antenna based on a convex-H-shaped slot composite structure. Background Technology

[0002] In modern wireless communication systems, the design requirements for multi-band antennas are becoming increasingly prominent. These antennas need to maintain stable radiation patterns, good impedance matching characteristics, and high radiation efficiency simultaneously across multiple discrete frequency bands. Patch antennas, with their advantages of low profile, lightweight design, ease of planar integration, and compatibility with standard printed circuit board manufacturing processes, have become highly competitive antenna solutions in modern communication equipment. However, traditional microstrip patch antennas typically only support a single resonant frequency band. This inherent characteristic severely limits their application in multi-mode communication systems requiring multi-band collaborative operation, such as 5G NR, WiFi 6 / 6E, and the Internet of Things.

[0003] To expand their applications, existing research has explored various multi-band implementation methods, including multi-resonant structure loading such as U-grooves, L-shaped probes, multi-layer stacked patches, defect ground structures, and electromagnetic bandgap unit integration. However, these methods often lead to increased structural complexity, increased sensitivity to processing tolerances, and an increase in the number of dielectric substrate layers, resulting in higher manufacturing costs. They can even cause a significant decrease in radiation efficiency due to parasitic radiation effects. At the same time, the increased physical size is not conducive to the miniaturization and integration requirements of modern communication equipment.

[0004] With the coordinated deployment of Sub-6GHz and C / X-band spectrum resources, modern wireless communication systems are placing higher demands on the performance of multi-band patch antennas. Current applications require antennas to operate stably across multiple frequency bands to meet the needs of satellite communications, high-frequency WiFi, and radar systems. Antennas must simultaneously maintain excellent return loss, high radiation efficiency, and good port isolation across multiple discrete frequency bands, while avoiding structural redundancy caused by multi-layer stacking or complex feed networks. Furthermore, compact physical dimensions and low-cost manufacturing processes have become key considerations; traditional methods relying on high-dielectric-constant materials or precision machining are insufficient to balance performance and cost. Therefore, how to achieve synergistic optimization of multi-band, high-gain, and stable radiation characteristics on a single-layer dielectric substrate has become a significant challenge in current high-frequency antenna design. Utility Model Content

[0005] This invention addresses the aforementioned problems by providing a low-profile multi-band microstrip antenna based on a convex-H-shaped slot composite structure.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A low-profile multi-band microstrip antenna based on a convex-H-shaped slot composite structure includes a top radiating metal plate, a middle dielectric substrate, a bottom grounding metal plate, and a coaxial cable. The top radiating metal plate is integrally formed from a copper metal plate. The top radiating metal plate includes a convex patch with an H-shaped through slot formed on the convex patch, and the H-shaped through slot is located on the right side of the convex patch. The H-shaped through slot is formed by a pair of parallel transverse slots and a longitudinal slot. The top radiating metal plate, the middle dielectric substrate, and the bottom grounding metal plate are stacked sequentially from top to bottom. The coaxial cable passes through the top radiating metal plate, the middle dielectric substrate, and the bottom grounding metal plate.

[0008] Furthermore, the convex patch is composed of a rectangle and a regular octagon, the width of the rectangle is the same as the center distance of the regular octagon, and the left half of the regular octagon overlaps with the rectangle.

[0009] Furthermore, the transverse groove has a length of 20.5 mm and a width of 1.3 mm, and the longitudinal groove has a length of 7.7 mm and a width of 1 mm. A three-dimensional rectangular coordinate system is established with the center of the lower surface of the bottom grounding metal plate as the origin. The coordinates of the upper left corners of the two transverse grooves are (-6 mm, -3 mm, 1.645 mm) and (3 mm, -3 mm, 1.645 mm), respectively, and the coordinates of the upper left corner of the longitudinal groove are (-4.7 mm, 11 mm, 1.645 mm). The rectangle has a length of 70 mm and a width of 26.334 mm, and the coordinates of its upper left corner are (-35 mm, -26.334 mm, 1.645 mm). The asymmetry of the edges of the regular octagon is 26.334 mm, and the side length is 21.815 mm. The projections of the midpoint of the right side of the lower surface of the rectangle and the center point of the regular octagon onto the XY plane coincide with the origin of the three-dimensional rectangular coordinate system.

[0010] Furthermore, the intermediate layer dielectric substrate is made of Rogers RO5880 high-frequency laminate, with a relative permittivity of 2.20±0.02 and a dielectric loss of tanδ≤0.0009@10GHz / 23℃.

[0011] Furthermore, the intermediate layer dielectric substrate is a single-layer structure with dimensions of 80mm × 80mm × 1.575mm. The coaxial line has a height of 1.645mm, an inner conductor radius of 0.638mm, an outer conductor radius of 2mm, and the coordinates of the projection of the coaxial line axis onto the XY plane are (0, -7.5mm).

[0012] Furthermore, the underlying grounding metal plate is a copper metal plate, and the dimensions of the underlying grounding metal plate are 80mm×80mm×0.035mm.

[0013] Compared with the prior art, the present invention has the following advantages:

[0014] 1. The top radiating metal plate of this invention includes a convex patch with an H-shaped through-slot. Multi-band operation is achieved on the intermediate dielectric substrate, maintaining a compact size while avoiding the complex structure of traditional stacked antennas. In the design of the convex patch, HFSS software is used to analyze the current intensity variation of the top radiating metal plate. In areas of high current density, H-shaped through-slots are created to maintain low energy loss even at multiple frequencies. The multi-band microstrip antenna designed in this invention achieves multi-band operation from 4.89 to 8.52 GHz through an original design of the top radiating metal plate.

[0015] 2. This invention, while maintaining the inherent advantages of multi-band microstrip antennas such as small size, low profile, and easy integration, successfully overcomes the technical bottleneck of traditional microstrip antennas with only one frequency band. HFSS full-wave simulation optimization based on the finite element method shows that this invention achieves five independent resonant frequencies of 4.89 GHz, 5.98 GHz, 6.29 GHz, 6.92 GHz, and 8.52 GHz in the intermediate layer dielectric substrate, with each frequency band maintaining good performance. The return loss is better than -10 dB, with the 5.98 GHz and 8.52 GHz frequencies reaching -40 dB and -25 dB respectively. Figure 1 It has high consistency and meets the needs of modern communication systems for multi-band collaborative operation.

[0016] 3. HFSS full-wave simulation optimization based on finite element algorithm shows that the present invention can achieve excellent high-gain characteristics on the intermediate layer dielectric substrate, and the antenna radiation efficiency is significantly improved. The gain reaches 9.73dB at the 6.92GHz frequency point and the peak gain reaches 10.99dB at the 8.52GHz frequency point, which is 15%-20% higher than the traditional slotted antenna. While maintaining the simplicity of the single-layer structure, it achieves radiation performance comparable to or even better than multi-layer complex antennas. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of this utility model;

[0018] Figure 2 This is a top view of the present invention;

[0019] Figure 3 This is the front view of the present invention;

[0020] Figure 4 This is a geometric diagram showing the relationship between the rectangle and the regular octagon in the convex patch of this utility model;

[0021] Figure 5The return loss diagram of the multi-band microstrip antenna of this utility model is shown.

[0022] Figure 6 This is a simulated VSWR (voltage standing wave ratio) curve of the multi-band microstrip antenna of this utility model;

[0023] Figure 7 This is a simulated gain curve of the multi-band microstrip antenna of this utility model within its frequency band.

[0024] Figure 8 The radiation diagrams of the E and H planes at the 4.9 GHz resonant point of the multi-band microstrip antenna of this invention are shown.

[0025] Figure 9 The radiation diagrams of the E and H planes at the 6.0 GHz resonant point of the multi-band microstrip antenna of this invention are shown.

[0026] Figure 10 The radiation diagrams of the E and H planes at the 6.3 GHz resonant point of the multi-band microstrip antenna of this invention are shown.

[0027] Figure 11 The radiation diagrams of the E and H planes at the 6.9 GHz resonant point of the multi-band microstrip antenna of this invention are shown.

[0028] Figure 12 The radiation diagrams of the E and H planes at the 8.5 GHz resonant point of the multi-band microstrip antenna of this invention are shown.

[0029] In the figure, the top layer is a radiating metal plate 1, the middle layer is a dielectric substrate 2, the bottom layer is a grounding metal plate 3, the coaxial line is 4, the convex patch is 101, the H-shaped through groove is 102, the rectangle is 101a, the regular octagon is 101b, the transverse groove is 102a, and the longitudinal groove is 102b. Detailed Implementation

[0030] To further illustrate the technical solution of this utility model, the following embodiments will be used to further explain this utility model.

[0031] like Figures 1 to 4As shown, a low-profile multi-band microstrip antenna based on a convex-H-shaped slot composite structure includes a top radiating metal plate 1, a middle dielectric substrate 2, a bottom grounding metal plate 3, and a coaxial cable 4. The top radiating metal plate 1 is integrally formed from a copper metal plate. The top radiating metal plate 1 includes a convex patch 101, which is composed of a rectangle 101a and a regular octagon 101b. The width of the rectangle 101a is the same as the center-to-side distance of the regular octagon 101b. The left half of the regular octagon 101b overlaps with the rectangle 101a. An H-shaped through slot 102 is provided on the top, and the H-shaped through slot 102 is located on the right side of the convex patch 101. The H-shaped through slot 102 is composed of a pair of parallel transverse slots 102a and a longitudinal slot 102b. The top radiating metal plate 1, the middle dielectric substrate 2 and the bottom grounding metal plate 3 are stacked sequentially from top to bottom. The coaxial line 4 is provided through the top radiating metal plate 1, the middle dielectric substrate 2 and the bottom grounding metal plate 3. The signal is fed into the convex patch 101 through the coaxial line 4, and the 50Ω impedance matching is achieved through the middle dielectric substrate 2 and the bottom grounding metal plate 3 to form an antenna.

[0032] The transverse groove 102a has a length of 20.5 mm and a width of 1.3 mm, and the longitudinal groove 102b has a length of 7.7 mm and a width of 1 mm. A three-dimensional rectangular coordinate system is established with the center of the lower surface of the bottom grounding metal plate 3 as the origin. The coordinates of the upper left corners of the two transverse grooves 102a are (-6 mm, -3 mm, 1.645 mm) and (3 mm, -3 mm, 1.645 mm), respectively. The coordinates of the upper left corner of the longitudinal groove 102b are (-4.7 mm, 11 mm, 1.645 mm). The rectangle 101a has a length of 70 mm and a width of 26.334 mm, and the coordinates of its upper left corner are (-35 mm, -26.334 mm). The center distance of the regular octagon 101b is 26.334 mm, and the side length is 21.815 mm. The projections of the midpoint of the right side of the lower surface of the rectangle 101a and the center point of the regular octagon 101b onto the XY plane coincide with the origin of the three-dimensional rectangular coordinate system.

[0033] The intermediate layer dielectric substrate 2 is made of Rogers RO5880 high-frequency laminate with a relative permittivity of 2.20±0.02 and a dielectric loss of tanδ≤0.0009@10GHz / 23℃. The intermediate layer dielectric substrate 2 is a single-layer structure with dimensions of 80mm×80mm×1.575mm. The coaxial line 4 has a height of 1.645mm, a radius of 0.638mm for the inner conductor, a radius of 2mm for the outer conductor, and the coordinates of the projection of the axis of the coaxial line 4 onto the XY plane are (0, -7.5mm).

[0034] The bottom grounding metal plate 3 is a copper metal plate, and the dimensions of the bottom grounding metal plate 3 are 80mm×80mm×0.035mm.

[0035] Its working principle: The radio frequency (RF) signal output by the radio transmitter is transmitted to the multi-band microstrip antenna via a coaxial line. The coaxial line runs through a three-layer structure consisting of a top radiating metal plate, a middle dielectric substrate, and a bottom ground metal plate. Its inner conductor forms an ohmic contact with the feed point of the convex patch, while the outer conductor maintains an electrical connection with the bottom ground metal plate. When the multi-band microstrip antenna operates, the RF signal excites a time-varying current on the surface of the convex patch via the inner conductor of the coaxial line. These currents excite specific modes of electromagnetic field oscillation in the resonant cavity formed by the middle dielectric substrate and the bottom ground metal plate. Through the synergistic effect of the carefully designed convex patch geometry and the H-shaped through-slot, the multi-band microstrip antenna achieves effective impedance matching in multiple discrete frequency bands (4.89-8.52 GHz), efficiently coupling electromagnetic energy into free space. The degree of matching between the characteristic impedance of the coaxial cable and the input impedance of the multi-band microstrip antenna directly determines the power transmission efficiency, while the multi-resonance characteristics of the convex patch ensure that a good voltage standing wave ratio and radiation efficiency can be maintained in the target frequency band, thereby meeting the stringent requirements of modern wireless communication systems for multi-band radiation performance.

[0036] Since multi-band microstrip antennas operate in free space, to make their operating parameters closer to reality, after creating the multi-band microstrip antenna structural model, when analyzing the antenna performance parameters using HFSS (simulation software), the boundary conditions of the multi-band microstrip antenna need to be set to ideal conductor boundaries. The distance between the radiating boundary surface (i.e., the air cavity surface) and the radiator needs to be no less than a quarter wavelength. The bottom surface of the intermediate dielectric substrate of the multi-band microstrip antenna model needs to be set to an ideal boundary. The input port of the multi-band microstrip antenna is set to lumped port excitation. The multi-band microstrip antenna is set to a fast frequency sweep type, and its performance in the 4GHz-9.5GHz frequency band is analyzed and calculated.

[0037] The multi-band microstrip antenna of this invention was simulated using HFSS full-wave simulation software based on the finite element method, and scanned within the range of 4-9.5 GHz. Figure 5 As shown in the diagram, referring to the S11 return loss diagram of the multi-band microstrip antenna, it can be seen that the multi-band microstrip antenna has resonant points at 4.89 GHz, 5.98 GHz, 6.29 GHz, 6.92 GHz, and 8.52 GHz in the frequency range where the return loss is less than -10dB. It also exhibits good stability in the lower frequency range, meeting the design requirements for operation in the C-band and X-band.

[0038] like Figure 6As shown, the voltage standing wave ratio (VSWR) of the multi-band microstrip antenna meets the application requirement of less than 2 within the operating frequency band. Meanwhile, the gain performance of the multi-band microstrip antenna is also relatively excellent; see Appendix. Figure 7 The maximum gain parameter is above 2dBi throughout its bandwidth. The maximum gains at 4.89 GHz, 5.98 GHz, 6.29 GHz, 6.92 GHz, and 8.52 GHz are 6.58, 8.50, 7.00, 6.91, and 10.43dBi, respectively. Therefore, the multi-band microstrip antenna designed in this invention meets the operating conditions for practical applications.

[0039] As attached Figures 8 to 12 As shown in the attached figures, the above figures are the radiation patterns generated by the multi-band microstrip antenna of this utility model at 4.89 GHz, 5.98 GHz, 6.29 GHz, 6.92 GHz and 8.52 GHz respectively. Therefore, we can see that the multi-band microstrip antenna of this utility model has good directivity in the frequency band and meets the design requirements.

[0040] The foregoing has shown and described the main features and advantages of this utility model. It will be apparent to those skilled in the art that this utility model is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this utility model. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of this utility model is defined by the appended claims rather than the foregoing description, and thus all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this utility model.

[0041] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A low-profile multi-band microstrip antenna based on a convex-H-shaped slot composite structure, characterized in that: The system includes a top radiating metal plate (1), an intermediate dielectric substrate (2), a bottom grounding metal plate (3), and a coaxial cable (4). The top radiating metal plate (1) is integrally formed from a copper metal plate. The top radiating metal plate (1) includes a convex patch (101). An H-shaped through groove (102) is formed on the convex patch (101), and the H-shaped through groove (102) is located on the right side of the convex patch (101). The H-shaped through groove (102) is formed by connecting a pair of parallel transverse grooves (102a) and a longitudinal groove (102b). The top radiating metal plate (1), the intermediate dielectric substrate (2), and the bottom grounding metal plate (3) are stacked sequentially from top to bottom. The coaxial cable (4) passes through the top radiating metal plate (1), the intermediate dielectric substrate (2), and the bottom grounding metal plate (3).

2. The low-profile multi-band microstrip antenna based on a convex-H-shaped slot composite structure according to claim 1, characterized in that: The convex patch (101) is composed of a rectangle (101a) and a regular octagon (101b). The width of the rectangle (101a) is the same as the center distance of the regular octagon (101b). The left half of the regular octagon (101b) overlaps with the rectangle (101a).

3. A low-profile multi-band microstrip antenna based on a convex-H-shaped slot composite structure according to claim 2, characterized in that: The transverse groove (102a) has a length of 20.5 mm and a width of 1.3 mm, and the longitudinal groove (102b) has a length of 7.7 mm and a width of 1 mm. A three-dimensional rectangular coordinate system is established with the center of the lower surface of the bottom grounding metal plate (3) as the origin. The coordinates of the upper left corners of the two transverse grooves (102a) are (-6 mm, -3 mm, 1.645 mm) and (3 mm, -3 mm, 1.645 mm), respectively, and the coordinates of the upper left corner of the longitudinal groove (102b) are (-4.7 mm, 11 mm, 1.645 mm). The rectangle (101a) has a length of 70 mm and a width of 26.334 mm, and the coordinates of its upper left corner are (-35 mm, -26.334 mm). The center distance of the regular octagon (101b) is 26.334 mm, and the side length is 21.815 mm. The projections of the midpoint of the right side of the lower surface of the rectangle (101a) and the center point of the regular octagon (101b) onto the XY plane coincide with the origin of the three-dimensional rectangular coordinate system.

4. A low-profile multi-band microstrip antenna based on a convex-H-shaped slot composite structure according to any one of claims 1 to 3, characterized in that: The intermediate layer dielectric substrate (2) is made of Rogers RO5880 high-frequency laminate with a relative permittivity of 2.20±0.02 and a dielectric loss tanδ≤0.0009@10GHz / 23℃.

5. A low-profile multi-band microstrip antenna based on a convex-H-shaped slot composite structure according to claim 4, characterized in that: The intermediate layer dielectric substrate (2) is a single-layer structure. The dimensions of the intermediate layer dielectric substrate (2) are 80mm×80mm×1.575mm. The height of the coaxial line (4) is 1.645mm. The radius of the inner conductor in the coaxial line (4) is 0.638mm. The radius of the outer conductor in the coaxial line (4) is 2mm. The coordinates of the projection of the axis of the coaxial line (4) onto the XY plane are (0, -7.5mm).

6. A low-profile multi-band microstrip antenna based on a convex-H-shaped slot composite structure according to claim 5, characterized in that: The bottom grounding metal plate (3) is a copper metal plate, and the size of the bottom grounding metal plate (3) is 80mm×80mm×0.035mm.

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