A millimeter-wave band stripline probe antenna based on microwave PCB board

Abstract

The present invention discloses a millimeter-wave frequency band stripline probe antenna based on a microwave PCB. The antenna comprises a tapered horn, an air waveguide, a microwave PCB upper core board, a prepreg sheet (PP), a microwave PCB lower core board, and metalized vias. The microwave PCB upper core board, the prepreg sheet (PP), the microwave PCB lower core board, and the metalized vias are sequentially stacked and pressed together to form a microwave multilayer PCB. The tapered horn is connected to the air waveguide and then fixed to the upper surface of the microwave multilayer PCB by screws, forming a millimeter-wave frequency band stripline probe antenna. The present invention has the advantages of large relative bandwidth, low insertion loss, small standing wave, and adjustable antenna gain. Furthermore, the antenna has a simple and compact structure, low cost, and is easily integrated with a millimeter-wave chip on a microwave PCB.

Description

Technical Field

[0001] The present invention belongs to the technical field of millimeter wave communications, and in particular relates to a millimeter wave frequency band stripline probe antenna based on a microwave PCB board. Background Art

[0002] With the rise of millimeter-wave body security inspections and millimeter-wave communications, there is growing demand for the integrated integration of millimeter-wave circuits and antennas on low-cost microwave multi-layer PCBs. Common miniaturized millimeter-wave antennas are mostly microstrip patch antennas and microstrip probe antennas. Millimeter-wave microstrip patch antennas are inefficient, with non-adjustable radiation patterns and gain. Millimeter-wave microstrip probe antennas often use a probe or fin transition between the microstrip line and the waveguide. This transition requires a back-cavity slot structure, embedding the microstrip line within the waveguide structure. This results in a larger volume and is not conducive to multi-chip and antenna integration. Furthermore, in the millimeter-wave frequency band, the microstrip transmission feeder has high insertion loss.

[0003] It can be seen that those skilled in the art are in urgent need of a millimeter wave antenna suitable for engineering use, which has low insertion loss, small size, low cost, and convenient antenna circuit integration. Summary of the Invention

[0004] The technology of the present invention solves the problem: Overcoming the shortcomings of the existing technology, providing a millimeter-wave frequency band stripline probe antenna based on a microwave PCB board, which has the advantages of large relative bandwidth, low insertion loss, small standing wave, and adjustable antenna gain. In addition, it has a simple and compact structure, low cost, and is convenient for integration with a millimeter-wave chip on a microwave PCB board.

[0005] In order to solve the above technical problems, the present invention discloses a millimeter-wave band stripline probe antenna based on a microwave PCB board, comprising: a square cone gradient horn, an air waveguide, a microwave PCB upper core board, a prepreg PP, a microwave PCB lower core board and metallized vias;

[0006] The microwave PCB upper core board, prepreg PP, microwave PCB lower core board and metallized vias are stacked and pressed in sequence to form a microwave multi-layer PCB board;

[0007] After the square cone gradient horn is connected to the air waveguide, it is fixed to the upper surface of the microwave multi-layer PCB board by screws to form a millimeter wave frequency band stripline probe antenna.

[0008] In the above-mentioned millimeter-wave band stripline probe antenna based on a microwave PCB board, through holes matching the shape of the metallized vias are reserved on the upper core board, the prepreg PP, and the lower core board; the metallized vias pass through the through holes vertically through the upper core board, the prepreg PP, and the lower core board, forming a square dielectric waveguide surrounded by the prepreg dielectric and the core board dielectric.

[0009] In the above-mentioned millimeter-wave frequency band stripline probe antenna based on a microwave PCB, the microwave PCB upper core board and prepreg PP form a stripline transmission structure. The 50-ohm stripline on the lower surface of the microwave PCB upper core board gradually transforms into a stripline gradient probe. The millimeter-wave electromagnetic field energy is transferred through the stripline gradient probe to the square dielectric waveguide formed by the microwave multilayer PCB board. The energy is then fed into the air waveguide and gradient square cone horn, and finally radiated out through the gradient square cone horn.

[0010] In the above-mentioned millimeter-wave band stripline probe antenna based on a microwave PCB, the dielectric constants of the upper and lower core boards of the microwave PCB are consistent with the dielectric constant of the prepreg PP to ensure uniform dielectric properties in the square dielectric waveguide.

[0011] In the above-mentioned millimeter-wave frequency band stripline probe antenna based on a microwave PCB board, the thickness of the prepreg sheet PP and the lower core board of the microwave PCB meet the following requirements: the lower metal layer of the lower core board of the microwave PCB serves as the short-circuit surface of the square dielectric waveguide, and the vertical distance between the short-circuit surface and the stripline gradient probe is: one-quarter of the wavelength of the millimeter wave in the square dielectric waveguide.

[0012] In the above-mentioned millimeter-wave band stripline probe antenna based on a microwave PCB board, the square cone tapered horn is connected to the air waveguide and then fixed to the upper surface of the upper core board of the microwave PCB with screws to ensure that the millimeter-wave energy in the square dielectric waveguide can be fully fed into the air waveguide.

[0013] In the above-mentioned millimeter-wave band stripline probe antenna based on a microwave PCB board, an SMT chip I and an SMT chip II are respectively attached to the upper and lower surfaces of the microwave multi-layer PCB board to realize the integration of the millimeter-wave band stripline probe antenna and the circuit design.

[0014] In the above-mentioned millimeter wave band stripline probe antenna based on microwave PCB board,

[0015] The long side length, short side length and height of the square dielectric waveguide meet the standard waveguide requirements of the frequency band to achieve antenna impedance matching;

[0016] The stripline tapered probe extends to the exact center of the square dielectric waveguide;

[0017] There is a transition section in the middle of the stripline tapered probe, and the width of the transition section is smaller than the maximum width of the stripline tapered probe, so as to achieve fine adjustment of the center frequency of the antenna.

[0018] In the above-mentioned millimeter-wave band stripline probe antenna based on a microwave PCB board, the air waveguide is a rectangular waveguide; wherein the long side length of the air waveguide is greater than the long side length of the square dielectric waveguide, and the short side length of the air waveguide is greater than the short side length of the square dielectric waveguide.

[0019] In the above-mentioned millimeter-wave frequency band stripline probe antenna based on a microwave PCB board, the bottom surface of the square tapered horn coincides with the air waveguide. In the process of the square tapered horn tapering upward from the air waveguide, the length of the long side remains unchanged, and the short side gradually changes to be equal to the long side.

[0020] The present invention has the following advantages:

[0021] The present invention discloses a millimeter-wave frequency band stripline probe antenna based on a microwave PCB board. The stripline probe antenna has the advantages of large relative bandwidth, low insertion loss, small standing wave, and adjustable antenna gain. In addition, the antenna has a simple and compact structure and low cost. It can be easily integrated with a millimeter-wave chip on the microwave PCB board and can be used as a millimeter-wave MIMO array antenna in millimeter-wave human body security inspection equipment and millimeter-wave communication equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is an exploded schematic diagram of a millimeter-wave band stripline probe antenna based on a microwave PCB board in an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the assembly of a millimeter-wave band stripline probe antenna based on a microwave PCB board in an embodiment of the present invention;

[0024] Figure 3 1 is a schematic structural diagram of a square dielectric waveguide according to an embodiment of the present invention;

[0025] Figure 4 1 is a schematic structural diagram of a stripline gradient probe according to an embodiment of the present invention;

[0026] Figure 5 is a schematic structural diagram of an air waveguide according to an embodiment of the present invention;

[0027] Figure 6 It is a structural schematic diagram of a square gradient speaker in an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments disclosed in the present invention will be described in further detail below with reference to the accompanying drawings.

[0029] like Figure 1In this embodiment, the millimeter-wave band stripline probe antenna based on a microwave PCB includes: a tapered horn 1, an air waveguide 2, a microwave PCB upper core board 3, a prepreg PP4, a microwave PCB lower core board 5, and metalized vias 6. The microwave PCB upper core board 3, prepreg PP4, microwave PCB lower core board 5, and metalized vias 6 are sequentially stacked and pressed together to form a microwave multilayer PCB. The tapered horn 1 is connected to the air waveguide 2 and then fixed to the top surface of the microwave multilayer PCB using screws 10, forming the millimeter-wave band stripline probe antenna.

[0030] Preferably, in this embodiment, through holes matching the shape of the metallized vias 6 are reserved on the upper core board 3, the semi-cured sheet PP4 and the lower core board 5. The metallized vias 6 pass through the through holes vertically through the upper core board 3, the semi-cured sheet PP4 and the lower core board 5 to form a square dielectric waveguide surrounded by the semi-cured sheet medium and the core board medium.

[0031] Preferably, in this embodiment, the microwave PCB upper core board 3 and prepreg sheet PP4 form a stripline transmission structure, and the 50-ohm stripline on the lower surface of the microwave PCB upper core board 3 tapers into a stripline taper probe 7. Millimeter-wave electromagnetic field energy is transferred through the stripline taper probe 7 to the square dielectric waveguide formed by the microwave multilayer PCB. The energy is then fed into the air waveguide 2 and the tapered square cone horn 1, and finally radiated out through the tapered square cone horn 1.

[0032] Preferably, in this embodiment, the dielectric constants of the microwave PCB upper core board 3 and the microwave PCB lower core board 5 are consistent with the dielectric constant of the prepreg PP4 to ensure uniform dielectric in the square dielectric waveguide.

[0033] Preferably, in this embodiment, the thicknesses of prepreg sheet PP4 and microwave PCB lower core board 5 meet the following requirements: the lower metal layer of microwave PCB lower core board 5 serves as a short-circuit path for the square dielectric waveguide. The vertical distance between the short-circuit path and the stripline taper probe 7 is equal to a quarter of the wavelength of a millimeter wave in the square dielectric waveguide.

[0034] Preferably, Figure 2 In this embodiment, the tapered square horn 1 is connected to the air waveguide 2 and then secured to the top surface of the microwave PCB's upper core board 3 via screws 10. This ensures that the millimeter-wave energy in the square dielectric waveguide is fully fed into the air waveguide 2. Furthermore, an SMT chip I 8 and an SMT chip II 9 are attached to the top and bottom surfaces of the microwave multilayer PCB, respectively, to integrate the millimeter-wave band stripline probe antenna with the circuit design.

[0035] Preferably, in this embodiment, Figure 3The long side length, short side length, and height of the square dielectric waveguide must meet standard waveguide requirements for the frequency band to achieve antenna impedance matching. The spacing between metallized vias (6) must be no less than 0.5 mm. While ensuring sufficient spacing, the metallized vias should be distributed as much as possible around the long and short sides of the square dielectric waveguide to ensure good radiation performance.

[0036] Preferably, Figure 4 The stripline taper probe 7 generally extends to the exact center of the square dielectric waveguide. Based on this length, fine-tuning can be performed to adjust the antenna's center frequency. Furthermore, a transition section 71 is provided in the middle of the stripline taper probe 7. The width of the transition section 71 is smaller than the maximum width of the stripline taper probe 7. Fine-tuning the width of the transition section 71 also adjusts the antenna's center frequency.

[0037] Preferably, Figure 5 The air waveguide 2 can be a rectangular waveguide. The long side of the air waveguide 2 is typically longer than that of a square dielectric waveguide, and the short side of the air waveguide 2 is typically longer than that of a square dielectric waveguide. For example, the dimensions of a square dielectric waveguide can be calculated by dividing the length of the air waveguide by the square root of the dielectric constant of the square dielectric waveguide. In other words, the long and short side lengths of the air waveguide 2 can be fine-tuned based on the standard waveguide. Simultaneously, these adjustments can be made in conjunction with the square dielectric waveguide to achieve a transition from a square dielectric waveguide to an air waveguide.

[0038] Preferably, Figure 6 The lower bottom surface of the square gradient speaker 1 coincides with the air waveguide 2. In the process of the square gradient speaker 1 gradually changing upward from the air waveguide 2, the length of the long side remains unchanged, and the short side gradually changes to be equal to the long side.

[0039] As can be seen from the above, in this application, the working principle of the millimeter wave band stripline probe antenna based on the microwave PCB board is as follows:

[0040] Millimeter-wave energy passes through the stripline taper probe 7 and transitions to the square dielectric waveguide (formed by metallized vias 6 vertically penetrating the upper core board 3, prepreg sheet PP4, and lower core board 5). The millimeter-wave electromagnetic field transforms from the stripline's TEM transmission mode to the square dielectric waveguide's TE10 transmission mode. The square dielectric waveguide, formed by metallized vias 6 vertically penetrating the upper core board 3, prepreg sheet PP4, and lower core board 5, ensures that the electromagnetic wave does not generate higher-order modes other than the main mode. During this process, the proper setting of the length of the stripline taper probe 7, the lengths of the long and short sides of the square dielectric waveguide, and the vertical distance between the short-circuit surface and the stripline taper probe 7 ensures impedance matching from the stripline to the square dielectric waveguide, thereby ensuring low input standing waves and insertion loss.

[0041] Furthermore, the energy in the square dielectric waveguide is fed vertically upward into the air waveguide 2 through the dielectric waveguide opening on the upper surface of the microwave PCB upper core board 3. Since the wavelength of the air waveguide 2 is greater than the wavelength of the square dielectric waveguide, the long and short side dimensions of the square dielectric waveguide are set to be smaller than the long and short side dimensions of the air waveguide 2 to ensure impedance matching of the electromagnetic field fed from the square dielectric waveguide to the air waveguide 2.

[0042] Finally, electromagnetic energy is transmitted from the air waveguide 2 through the tapered square-cone tapered horn 1 into the air. During the tapered process, the long side of the air waveguide 2 remains unchanged, while the short side tapers to the same length as the long side, ensuring that the H-plane and E-plane patterns of the tapered square-cone tapered horn 1 are identical. During this process, the pattern and antenna gain can be controlled by controlling the tapered length of the tapered square-cone tapered horn 1.

[0043] Although the present invention has been disclosed above in terms of preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solutions of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the scope of protection of the technical solutions of the present invention.

[0044] The contents not described in detail in the specification of the present invention belong to the common knowledge of professionals in this field.

Claims

1. A millimeter wave band stripline probe antenna based on a microwave PCB board, characterized in that: include: A square cone gradient horn (1), an air waveguide (2), a microwave PCB upper core board (3), a prepreg sheet PP (4), a microwave PCB lower core board (5) and a metallized via (6); A microwave PCB upper core board (3), a prepreg sheet PP (4), a microwave PCB lower core board (5) and a metallized via (6) are sequentially stacked and pressed together to form a microwave multilayer PCB board; After the square cone gradient horn (1) is connected to the air waveguide (2), it is fixed on the upper surface of the microwave multilayer PCB board by screws (10) to form a millimeter wave frequency band stripline probe antenna; Through holes matching the shape of the metallized via holes (6) are reserved on the upper core board (3), the prepreg sheet PP (4) and the lower core board (5); the metallized via holes (6) pass through the through holes and vertically penetrate the upper core board (3), the prepreg sheet PP (4) and the lower core board (5), forming a square dielectric waveguide surrounded by the prepreg sheet dielectric and the core board dielectric; The microwave PCB upper core board (3) and the prepreg sheet PP (4) form a stripline transmission structure, and the 50-ohm stripline on the lower surface of the microwave PCB upper core board (3) gradually transforms into a stripline gradient probe (7); wherein the millimeter wave electromagnetic field energy is transferred to the square dielectric waveguide formed by the microwave multilayer PCB board through the stripline gradient probe (7), and then the energy is fed into the air waveguide (2) and the gradient square cone horn (1), and finally the magnetic field energy is radiated out through the gradient square cone horn (1); The dielectric constants of the microwave PCB upper core board (3) and the microwave PCB lower core board (5) are kept consistent with the dielectric constant of the prepreg sheet PP (4) to ensure uniform dielectric in the square dielectric waveguide; The thickness of the prepreg sheet PP (4) and the microwave PCB lower core board (5) meet the following requirements: the lower metal layer of the microwave PCB lower core board (5) serves as a short-circuit surface of the square dielectric waveguide, and the vertical distance between the short-circuit surface and the stripline gradient probe (7) is: the wavelength of a quarter millimeter wave in the square dielectric waveguide; An SMT chip I (8) and an SMT chip II (9) are respectively attached to the upper and lower surfaces of the microwave multilayer PCB board to realize the integration of the millimeter wave band stripline probe antenna and the circuit design; The long side length, short side length and height of the square dielectric waveguide meet the standard waveguide requirements of the frequency band, so as to achieve antenna impedance matching; the stripline gradient probe (7) extends to the center of the square dielectric waveguide; a transition section (71) is provided in the middle of the stripline gradient probe (7), and the width of the transition section (71) is smaller than the maximum width of the stripline gradient probe (7), so as to achieve fine adjustment of the center frequency of the antenna; The working principle of the millimeter wave band stripline probe antenna based on microwave PCB board is as follows: Millimeter wave energy passes through the stripline gradient probe (7) and transitions to the square dielectric waveguide. The millimeter wave electromagnetic field is transformed from the TEM transmission mode of the stripline to the TE10 transmission mode in the square dielectric waveguide. The square dielectric waveguide formed by the metallized via (6) vertically penetrating the upper core board (3), the semi-cured sheet PP (4) and the lower core board (5) ensures that the electromagnetic wave will not generate higher-order modes other than the main mode. Energy in the square dielectric waveguide is fed vertically upward into the air waveguide (2) through a dielectric waveguide opening on the upper surface of the microwave PCB upper core board (3), and the long and short side dimensions of the square dielectric waveguide are set to be smaller than the long and short side dimensions of the air waveguide (2) to ensure impedance matching of the electromagnetic field fed from the square dielectric waveguide into the air waveguide (2); Electromagnetic energy is transmitted from an air waveguide (2) through a square cone gradient horn (1) with a gradient opening into the air; wherein the long side of the air waveguide (2) remains unchanged during the gradient process, and the short side gradually changes to be equal to the long side, so that the H-plane directional pattern and the E-plane directional pattern of the square cone gradient horn (1) are the same; After the square cone gradient horn (1) is connected to the air waveguide (2), it is fixed to the upper surface of the microwave PCB upper core board (3) by screws (10) to ensure that the millimeter wave energy in the square dielectric waveguide can be fully fed into the air waveguide (2); The air waveguide (2) is a rectangular waveguide; wherein the long side length of the air waveguide (2) is greater than the long side length of the square dielectric waveguide, and the short side length of the air waveguide (2) is greater than the short side length of the square dielectric waveguide; The bottom surface of the square gradient speaker (1) overlaps with the air waveguide (2). When the square gradient speaker (1) gradually changes upward from the air waveguide (2), the length of the long side remains unchanged, and the short side gradually changes to be equal to the long side.

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