A broadband decoupled laminated microstrip patch antenna

Abstract

The present invention discloses a broadband decoupled laminated microstrip patch antenna. The antenna has a layered structure and includes a first dielectric substrate and a second dielectric substrate arranged in parallel. A metal ring laminated resonator structure is provided on the first dielectric substrate, comprising an upper annular metal patch on the upper surface of the first dielectric substrate, a lower annular metal patch on the lower surface of the first dielectric substrate, and an upper metal column penetrating the first dielectric substrate. A parasitic metal patch is provided inside the lower annular metal patch. A driven metal patch is provided on the upper surface of the second dielectric substrate, and a metal cosine coupled line resonator structure is provided between two adjacent driven metal patches. A metal ground is provided on the lower surface of the second dielectric substrate. The present invention combines the characteristics of wide decoupling bandwidth, wide impedance bandwidth, high stability, easy integration, low profile, and scalability for multiple antennas.

Description

Technical Field

[0001] The invention relates to a broadband decoupling laminated microstrip patch antenna, belonging to the field of antennas in radio equipment. Background Art

[0002] Multiple-Input Multiple-Output (MIMO) technology plays a vital role in modern communication systems. With the development of mobile communications, wireless local area networks, and satellite communications, it has become one of the key technologies for increasing system channel capacity and improving data transmission rates.

[0003] Stacked microstrip patch antennas have become an effective antenna design solution for 5G base stations, client devices, and smartphones due to their wide impedance bandwidth, simple structure, ease of integration, and flexible polarization. However, compared to single-layer microstrip antennas, stacked microstrip patch antennas require a wider decoupling bandwidth because they have more radiation sources that affect mutual coupling.

[0004] There are three existing decoupling technologies for stacked microstrip patch antenna arrays. The first involves using an array antenna decoupling surface (ADS) to achieve the same amplitude and phase difference between the inherent mutual coupling and the strong coupling introduced by the ADS. Decoupling is achieved by controlling the amplitude through the size of the reflector and the phase through the height. This approach places strict requirements on the distance between the dielectric substrates, typically around 0.3λc (λc is the free-space wavelength at the antenna's center frequency). This makes it difficult to apply where height is limited, and the additional dielectric substrate increases costs. The second approach involves adding a vertical metal wall between the two elements to isolate them and suppress mutual coupling. This method increases the profile height and overall antenna size, significantly affecting the antenna radiation pattern and impedance matching. The third approach involves a decoupling network, which introduces indirect coupling with adjustable amplitude and phase to mitigate direct coupling caused by space and surface waves. However, the actual implementation involves transitioning from the connector to the microstrip line, resulting in significant losses, and the decoupling network requires a large substrate area, which is prohibitive on printed circuit boards, where real estate is at a premium. Summary of the Invention

[0005] Technical Problem: The present invention aims to provide a broadband decoupled laminated microstrip patch antenna. This solution addresses the aforementioned issues of narrow decoupling bandwidth, enabling flexible control of the decoupling bandwidth and decoupling depth when the thickness of the air layer between the substrates is limited, while also improving the impedance bandwidth and impedance matching of the antenna unit.

[0006] Technical solution: A broadband decoupled laminated microstrip patch antenna of the present invention is realized by the following technical measures:

[0007] The antenna has a layered structure and includes a first and a second dielectric substrate arranged in parallel. A metal ring stacked resonator structure is provided on the first dielectric substrate. The metal ring stacked resonator structure includes an upper annular metal patch on the upper surface of the first dielectric substrate, a lower annular metal patch on the lower surface of the first dielectric substrate, and upper metal pillars extending through the four sides of the upper and lower annular metal patches. The lower annular metal patch is located directly below the upper annular metal patch, and a parasitic metal patch is provided within the lower annular metal patch. A driven metal patch is provided on the upper surface of the second dielectric substrate, and a metal cosine coupled line resonator structure is provided between two adjacent driven metal patches. The metal cosine coupled line resonator structure includes a cosine curve-shaped metal patch and a lower metal pillar. A metal ground is provided on the lower surface of the second dielectric substrate. The cosine curve-shaped metal patch is connected to the metal ground via the lower metal pillar. The driven metal patch is connected to a metal probe. The metal probe passes through the second dielectric substrate and the metal ground to connect to the outside. A slot structure is also provided in the metal ground next to the metal probe.

[0008] The metal ring stacked resonator structure includes square ring metal patches arranged in an array on the first dielectric substrate and square ring metal patches under the first dielectric substrate.

[0009] An air layer is added between the first dielectric substrate and the second dielectric substrate. The thickness of the air layer is 0.015λc, where λc is the free space wavelength at the center frequency of the antenna.

[0010] The line width of the upper annular metal patch is 0.045λc-0.057λc; the side length is 0.45λc-0.46λc; where λc is the free space wavelength at the center frequency of the antenna.

[0011] The line width of the lower annular metal patch is 0.045λc-0.057λc; the side length is 0.45λc-0.46λc; where λc is the free space wavelength at the center frequency of the antenna.

[0012] The square ring metal patch is centered on the parasitic metal patch, and the distance between the square ring metal patch and the parasitic metal patch is 0.04λc.

[0013] The side length of the driven metal patch is 0.266λc×0.287λc, where λc is the free space wavelength at the center frequency of the antenna.

[0014] The width of the slot structure is 0.016λc, the length in the electric field direction is 0.28-0.31λc, and the length in the magnetic field direction is 0.33λc-0.35λc; wherein λc is the free space wavelength at the center frequency of the antenna.

[0015] The first dielectric substrate and the second dielectric substrate are made of polytetrafluoroethylene or epoxy resin.

[0016] The metal cosine coupled line resonator structure is used as a high-impedance surface unit array, with a spacing of 0.0097λc between each unit; the cosine curve-shaped metal patch has a width of 0.09λc and a length of 0.11λc-0.29λc, and the band gap range obtained by the dispersion curve is 4.68-5.98GHz; where λc is the free space wavelength at the center frequency of the antenna.

[0017] The first dielectric substrate and the second dielectric substrate are made of polytetrafluoroethylene or epoxy resin.

[0018] Beneficial effects: The present invention achieves the expansion of the decoupling bandwidth by combining the suppression of space waves and surface waves, and the mutual coupling suppression effect at each point in the band is adjustable. It solves the problem of flexible control of the decoupling bandwidth and decoupling depth when the thickness of the air layer between the substrates is limited. And while keeping the radiation pattern unchanged, the impedance bandwidth of the antenna is expanded and the impedance matching is improved. Among them, the cosine coupled line resonator uses its high impedance surface (HIS) characteristics to create a low-frequency mutual coupling zero point. The high-frequency mutual coupling zero point inherent in the stacked microstrip patch antenna array is adjusted to near the working frequency band by using the metal ring stacked resonator structure and the slot structure, avoiding the cost problem and height limitation and the problem of increased vertical space caused by the need to add an additional dielectric substrate to the array antenna decoupling surface (ADS) structure. At the same time, more importantly, the present invention also expands the original impedance bandwidth and impedance matching of the antenna, and keeps the radiation pattern basically unchanged. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A side cross-sectional structural diagram of a 1×2 broadband decoupling laminated microstrip patch antenna arranged along the electric field direction according to an embodiment of the present invention;

[0020] Figure 2 A front plan view of a first dielectric substrate of a 1×2 broadband decoupling laminated microstrip patch antenna arranged along the electric field direction according to an embodiment of the present invention;

[0021] Figure 3 A top view of the back side of the first dielectric substrate of a 1×2 broadband decoupling laminated microstrip patch antenna arranged along the electric field direction according to an embodiment of the present invention;

[0022] Figure 4 A top view of the second dielectric substrate of a 1×2 broadband decoupled laminated microstrip patch antenna arranged along the electric field direction according to an embodiment of the present invention;

[0023] Figure 5 It is the overall idea diagram of the present invention;

[0024] Figure 6Figure 1 is a comparison of the S-parameter effects of a 1×2 broadband decoupled laminated microstrip patch antenna arranged along the electric field direction according to an embodiment of the present invention, where (a) is a traditional laminated microstrip patch antenna array and (b) is an embodiment;

[0025] Figure 7 Figure 2 shows the surface current distribution of each layer of the substrate at the low-frequency mutual coupling zero point and the high-frequency mutual coupling zero point, respectively, for a 1×2 broadband decoupled laminated microstrip patch antenna arranged along the electric field direction according to an embodiment of the present invention. (a) shows the surface current distribution of each layer of the substrate at the low-frequency mutual coupling zero point, and (b) shows the surface current distribution of each layer of the substrate at the high-frequency mutual coupling zero point.

[0026] Figure 8 Comparison of the surface current distribution of the driving layer at the center frequency of a 1×2 broadband decoupled laminated microstrip patch antenna arranged along the electric field direction according to an embodiment of the present invention, where (a) shows a conventional laminated microstrip patch antenna array and (b) shows an embodiment;

[0027] Figure 9 2 is a dispersion curve of a cosine coupled line resonator in a 1×2 broadband decoupled laminated microstrip patch antenna arranged along the electric field direction according to an embodiment of the present invention;

[0028] Figure 10 The radiation pattern of a 1×2 broadband decoupled laminated microstrip patch antenna arranged along the electric field direction according to an embodiment of the present invention. Figure (a) shows the radiation pattern of the low-frequency mutual coupling zero point when port one is fed and port two is connected to a 50Ω load; Figure (b) shows the radiation pattern of the high-frequency mutual coupling zero point when port one is fed and port two is connected to a 50Ω load; Figure (c) shows the radiation pattern of the center frequency when port one is fed and port two is connected to a 50Ω load; Figure (d) shows the radiation pattern of the low-frequency mutual coupling zero point when port two is fed and port one is connected to a 50Ω load; Figure (e) shows the radiation pattern of the high-frequency mutual coupling zero point when port two is fed and port one is connected to a 50Ω load; Figure (f) shows the radiation pattern of the center frequency when port two is fed and port one is connected to a 50Ω load.

[0029] Figure 11 This is an S-parameter effect diagram of a 1×3 broadband decoupled laminated microstrip patch antenna arranged along the electric field direction according to an embodiment of the present invention.

[0030] The figure shows: a metal ring stacked resonator structure 1, an upper ring metal patch 101, an upper metal column 102, a lower ring metal patch 103, a first dielectric substrate 2, a parasitic metal patch 3, an air layer 4, a driven metal patch 5, a metal cosine coupled line resonator structure 6, a cosine curve-shaped metal patch 601, a lower metal column 602, a second dielectric substrate 7, a metal ground 8, a gap structure 9, and a metal probe 10. DETAILED DESCRIPTION

[0031] The present invention is described in detail below by way of examples. It should be noted that these examples are only intended to further illustrate the invention and are not to be construed as limiting the scope of protection of the present invention. Those skilled in the art may make non-essential improvements and adjustments based on the above-described disclosure.

[0032] The antenna is a layered structure, including a first dielectric substrate 2 and a second dielectric substrate 7 arranged in parallel. A metal ring stacked resonator structure 1 is provided on the first dielectric substrate 2. The metal ring stacked resonator structure 1 includes an upper annular metal patch 101 on the upper surface of the first dielectric substrate 2, a lower annular metal patch 103 on the lower surface of the first dielectric substrate 2, and an upper metal column 102 passing through the four sides of the upper annular metal patch 101 and the lower annular metal patch 103. The lower annular metal patch 103 is located directly below the upper annular metal patch 101, and the two are connected by the upper metal column 102. A metal ring stacked resonator structure 1 is provided inside the lower annular metal patch 103. There is a parasitic metal patch 3; a driven metal patch 5 is provided on the upper surface of the second dielectric substrate 7, and a metal cosine coupled line resonator structure 6 is provided between two adjacent driven metal patches 5. The metal cosine coupled line resonator structure 6 includes a cosine curve-shaped metal patch 601 and a lower metal pillar 602. A metal ground 8 is provided on the lower surface of the second dielectric substrate 7. The cosine curve-shaped metal patch 601 is connected to the metal ground 8 through the lower metal pillar 602. The driven metal patch 5 is connected to a metal probe 10, and the metal probe 10 passes through the second dielectric substrate 7 and the metal ground 8 to connect to the outside; a gap structure 9 is also provided on the metal ground 8 next to the metal probe 10.

[0033] Example:

[0034] The overall structure of the broadband decoupled laminated microstrip patch antenna of the present invention is as follows: Figures 1 to 4As shown, this broadband decoupled laminated microstrip patch antenna consists of a parasitic layer, an air layer, and a driving layer. The driving patches are arranged along the electric field direction, and there is no electrical connection between the parasitic layer and the driving layer. It includes a metal ring laminated resonator structure 1, an upper ring-shaped metal patch 101, an upper metal pillar 102, a lower ring-shaped metal patch 103, a first dielectric substrate 2, a parasitic metal patch 3, an air layer 4, a driving metal patch 5, a metal cosine coupled line resonator structure 6, a cosine curve-shaped metal patch 601, a lower metal pillar 602, a second dielectric substrate 7, a metal ground 8, a slot structure 9, and a metal probe 10. The metal ring laminated resonator structure 1 includes several square ring-shaped metal patches 101 and metal pillars 102 disposed on the upper surface of the first dielectric substrate 2, and a square ring-shaped metal patch 103 disposed on the lower surface of the first dielectric substrate 2. The metal cosine coupled line resonator structure includes a cosine curve-shaped metal patch 601 on the second dielectric substrate 7 , and a metal column 602 passes through the second dielectric substrate 7 to connect the cosine curve-shaped metal patch 601 on the second dielectric substrate 7 and the metal ground 8 .

[0035] Simulations show that this broadband decoupled laminated microstrip patch antenna operates normally at 5.8 GHz. It can flexibly and independently control the high- and low-frequency mutual coupling zeros to enhance the decoupling bandwidth, while also improving the impedance bandwidth and impedance matching. The impedance bandwidth increases by 135.27%, from 5.74-5.88 GHz (2.49%) to 5.62-5.96 GHz (5.86%). The decoupling bandwidth reaches a maximum of 5.42-5.98 GHz (9.6%), completely encompassing the impedance bandwidth of 5.62-5.96 GHz (5.86%). It also has minimal impact on the radiation pattern, and even with an air layer thickness limited to 0.015 λc, it still achieves mutual coupling suppression of spatial waves. The mutual coupling levels at the antenna's low- and high-frequency mutual coupling zeros reach -57.8 dB and -48.7 dB, respectively. At the center frequency of 5.8 GHz, the mutual coupling level decreases by 108.2%, from -23.2 dB to -48.3 dB. This proves the superiority and feasibility of using the stacked microstrip patch antenna of the present invention.

Claims

1. A broadband decoupled laminated microstrip patch antenna, characterized in that: The antenna is a layered structure, comprising a first dielectric substrate (2) and a second dielectric substrate (7) arranged in parallel. A metal ring stacked resonator structure (1) is provided on the first dielectric substrate (2). The metal ring stacked resonator structure (1) comprises an upper annular metal patch (101) on the upper surface of the first dielectric substrate, a lower annular metal patch (103) on the lower surface of the first dielectric substrate (2), and an upper metal column (102) passing through four sides of the upper annular metal patch (101) and the lower annular metal patch (103). The lower annular metal patch (103) is located directly below the upper annular metal patch (101), and the two are connected by the upper metal column (102). A parasitic metal patch (3) is provided inside the lower annular metal patch (103). 7) is provided with a driving metal patch (5), a metal cosine coupled line resonator structure (6) is provided between two adjacent driving metal patches (5), the metal cosine coupled line resonator structure (6) includes a cosine curve-shaped metal patch (601) and a lower metal column (602), a metal ground (8) is provided on the lower surface of the second dielectric substrate (7), the cosine curve-shaped metal patch (601) is connected to the metal ground (8) through the lower metal column (602), the driving metal patch (5) is connected to a metal probe (10), and the metal probe (10) passes through the second dielectric substrate (7) and the metal ground (8) to connect to the outside; a gap structure (9) is also provided on the metal ground (8) next to the metal probe (10); the driving metal patch (5) is located directly below the parasitic metal patch (3).

2. The broadband decoupled laminated microstrip patch antenna according to claim 1, wherein: described gold The metal ring stacked resonator structure (1) comprises square ring metal patches (101) arranged in an array on the upper surface of the first dielectric substrate (2) and square ring metal patches (103) on the lower surface of the first dielectric substrate (2).

3. The broadband decoupled laminated microstrip patch antenna according to claim 1, wherein: An air layer (4) is added between the first dielectric substrate (2) and the second dielectric substrate (7), wherein the thickness of the air layer is 0.015λc, where λc is the free space wavelength at the center frequency of the antenna.

4. The broadband decoupled laminated microstrip patch antenna according to claim 1, wherein: The line width of the upper annular metal patch (101) is 0.045λc-0.057λc; the side length is 0.45λc-0.46λc; wherein λc is the free space wavelength at the center frequency of the antenna.

5. The broadband decoupled laminated microstrip patch antenna according to claim 1, wherein: The line width of the lower annular metal patch (103) is 0.045λc-0.057λc; the side length is 0.45λc-0.46λc; wherein λc is the free space wavelength at the center frequency of the antenna.

6. The broadband decoupled laminated microstrip patch antenna according to claim 5, wherein: The square ring metal patch (103) is centered on the parasitic metal patch (3), and the distance between the square ring metal patch (103) and the parasitic metal patch (3) is 0.04λc.

7. The broadband decoupled laminated microstrip patch antenna according to claim 1, wherein: The side length of the driving metal patch (5) is 0.266λc×0.287λc; wherein λc is the free space wavelength at the center frequency of the antenna.

8. The broadband decoupled laminated microstrip patch antenna according to claim 1, wherein: The slot structure (9) has a width of 0.016λc, a length in the electric field direction of 0.28-0.31λc, and a length in the magnetic field direction of 0.33λc-0.35λc; wherein λc is the free space wavelength at the center frequency of the antenna.

9. The broadband decoupled laminated microstrip patch antenna according to claim 1, wherein: The materials of the first dielectric substrate (2) and the second dielectric substrate (7) are polytetrafluoroethylene or epoxy resin.

10. The broadband decoupled laminated microstrip patch antenna according to claim 1, wherein: The metal cosine coupled line resonator structure (6) is used as a high impedance surface unit array, and the spacing between each unit is 0.0097λc; the cosine curve-shaped metal patch (601) has a width of 0.09λc and a length of 0.11λc-0.29λc, and the band gap range obtained by the dispersion curve is 4.68-5.98 GHz; wherein λc is the free space wavelength at the center frequency of the antenna.

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