A PCB-based ultra-wideband millimeter wave antenna

Abstract

This utility model discloses an ultra-wideband millimeter-wave antenna based on a PCB board, comprising a substrate layer, a ground layer, multiple antenna elements, and multiple metallized vias. The antenna elements are disposed on the top surface of the substrate layer, and each antenna element has multiple radiating vias, at least one side of which has an outwardly expanding portion. The ground layer is disposed on the bottom surface of the substrate layer. The metallized vias are disposed within the substrate layer and connect the antenna elements to the ground layer, with multiple metallized vias arranged along the periphery of the antenna elements. The operating wavelength of the PCB-based ultra-wideband millimeter-wave antenna is λ. Among the multiple metallized vias connecting the same antenna element, the spacing between two adjacent metallized vias is less than or equal to 1 / 4λ. This ultra-wideband millimeter-wave antenna has the advantages of low cost, wide bandwidth, and high integration, and is particularly suitable for the 77GHz frequency band.

Description

Technical Field

[0001] This utility model relates to the field of antenna technology, and in particular to an ultra-wideband millimeter-wave antenna based on a PCB board. Background Technology

[0002] In the 77GHz band, metal waveguide, LTCC, and ceramic substrate solutions still dominate. To obtain usable gain, manufacturers have to rely on high-cost cavity structures and precision machining, resulting in material and process costs far exceeding those of PCBs. Due to the limitations of resonant radiation mechanisms, single-mode bandwidth is narrow, making it difficult to continuously cover the entire 72-81GHz new standard range. Systems can only add discrete front-ends or switch links to meet the requirements of broadband radar and high-speed communication. At the same time, high-dielectric ceramics and three-dimensional metal cavities have differences in thermal expansion, thickness, and vias compared to standard FR4 multilayer boards. The feed network and RF chip cannot be directly integrated coplanarly, and a transition structure must be introduced, resulting in additional insertion loss and space occupation. Electromagnetic leakage and surface waves further reduce radiation efficiency, making "low cost, wide bandwidth, and high integration" the technical bottleneck that 77GHz antennas have not yet been simultaneously overcome. Utility Model Content

[0003] The technical problem solved by this utility model is to provide a low-cost, wide-bandwidth, and highly integrated PCB-based ultra-wideband millimeter-wave antenna suitable for the 77GHz frequency band.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is: an ultra-wideband millimeter-wave antenna based on a PCB board, comprising:

[0005] Substrate layer;

[0006] Multiple antenna elements are disposed on the top surface of the substrate layer, and the antenna elements are provided with multiple radiation holes, at least one side of the radiation hole having an outwardly expanding portion;

[0007] A ground layer, wherein the ground layer is disposed on the bottom surface of the substrate layer;

[0008] Multiple metallized holes are disposed within the substrate layer and connect the antenna unit to the ground layer. The multiple metallized holes are arranged along the periphery of the antenna unit. The operating wavelength of the ultra-wideband millimeter-wave antenna based on the PCB board is λ. Among the multiple metallized holes connected to the same antenna unit, the spacing between two adjacent metallized holes is less than or equal to 1 / 4λ.

[0009] In one embodiment, the plurality of radiation holes on the antenna element are arranged in two staggered rows.

[0010] In one embodiment, at least one side of the radiation aperture has a plurality of the outward expansion portions, with adjacent outward expansion portions spaced apart.

[0011] In one embodiment, the radiation aperture has two outward expansions on one side, and the radiation aperture is generally U-shaped.

[0012] In one embodiment, the side edge of the radial aperture having the outward expansion is wavy.

[0013] In one embodiment, among the multiple metallized holes connected to the same antenna element, the spacing between two adjacent metallized holes is 1 / 10λ.

[0014] In one embodiment, the number of antenna elements is eight, and each antenna element is provided with five radiation holes.

[0015] In one embodiment, the antenna element includes a hole and a conductive portion, the hole and the conductive portion being far apart from each other, the conductive portions of each antenna element being close to each other, and the radiation hole being disposed in the hole.

[0016] In one embodiment, the spacing between the apertures of two adjacent antenna elements is 0.5λ-0.8λ.

[0017] In one embodiment, at least a portion of the antenna element has a bent portion located between the conductive portion and the aperture portion.

[0018] The beneficial effects of this utility model are as follows: This novel ultra-wideband millimeter-wave antenna structure based on PCB board is superior to traditional metal waveguide, LTCC and ceramic substrate solutions, which rely on high-cost cavity structures and precision processing, have narrow single-mode bandwidth and are difficult to continuously cover the entire 72-81GHz new standard range, and have the dilemma of thermal expansion and thickness differences between high dielectric ceramic and three-dimensional metal cavity and standard FR4 multilayer board, which require the introduction of transition structures and lead to additional insertion loss and electromagnetic leakage. This utility model is formed by laminating PCB board in one step, and forming a waveguide-like electromagnetic constraint channel around the periphery of the antenna unit with metallized holes with a spacing ≤λ / 4, locking the energy in the vertical radiation hole, and achieving high gain without cavity.

[0019] The wavy / stepped outward expansion of the radiation aperture extends the edge current path, causing the resonant point to shift continuously, thereby widening the narrowband resonant of the traditional patch to a continuous 9GHz bandwidth of 72-81GHz. A single antenna can cover the entire new standard area, eliminating the need for a discrete front end and switching links.

[0020] The entire power supply network and the RF chip are fabricated coplanarly on the same FR4 substrate, eliminating the ceramic-PCB transition structure. Insertion loss, surface wave and electromagnetic leakage are reduced simultaneously, and radiation efficiency is improved.

[0021] The thermal expansion coefficient of the PCB substrate layer material is close to that of the chip package, and its performance drift is lower than that of the metal waveguide solution in the range of -40℃ to 85℃, resulting in better temperature stability.

[0022] This enables the simultaneous achievement of "low cost, wide bandwidth, and high integration" on the same low-cost PCB platform, providing a mass-producible antenna solution for 77GHz automotive radar and high-speed communication. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the PCB-based ultrawideband millimeter-wave antenna structure in Example 1;

[0025] Figure 2 This is a perspective view of the PCB-based ultrawideband millimeter-wave antenna of Embodiment 1;

[0026] Figure 3 This is a top view of an antenna element in Embodiment 1;

[0027] Figure 4 The electric field contour plot of the antenna element at 74.5 GHz;

[0028] Figure 5 The radiation patterns of the antenna element in the E-plane and H-plane at 77 GHz;

[0029] Figure 6 This is a graph showing the S11 parameters of the PCB-based ultra-wideband millimeter-wave antenna in this embodiment.

[0030] Figure 7 This is a graph showing the S21 parameters of the PCB-based ultra-wideband millimeter-wave antenna in this embodiment.

[0031] Explanation of icon numbers:

[0032] 1. Substrate layer;

[0033] 2. Strata;

[0034] 3. Antenna element; 31. Hole; 32. Conductor; 33. Bending section;

[0035] 4. Metallized holes;

[0036] 5. Radial aperture; 51. Outer expansion section. Detailed Implementation

[0037] The purpose, features, and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings.

[0038] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0039] It should be noted that if the embodiments of this utility model involve directional indicators such as up, down, left, right, front, back, etc., the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture as shown in the attached figure. If the specific posture changes, the directional indicators will also change accordingly.

[0040] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," such descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.

[0041] Furthermore, if the meaning of "and / or" in the entire text is to include three parallel solutions, taking "and A / or B" as an example, it includes solution A, solution B, and a solution that simultaneously satisfies both A and B. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0042] In this application, unless otherwise expressly 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. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0043] Example 1

[0044] Please refer to Figures 1-7 The first embodiment of this utility model is as follows: Please refer to... Figures 1-3 An ultra-wideband millimeter-wave antenna based on a PCB board includes a substrate layer 1, a ground layer 2, multiple antenna elements 3, and multiple metallized holes 4; the substrate layer 1 is a low-loss high-frequency board material, and in this embodiment, the substrate layer 1 is a Rogers board material. The RO3003 substrate has a dielectric constant of 3.0, a loss tangent of 0.0013, and a thickness of 0.1 mm. The antenna unit 3 is disposed on the top surface of the substrate layer 1, and the antenna unit 3 has multiple radiation holes 5. At least one side of each radiation hole 5 has an outwardly expanding portion 51. The ground layer 2 is disposed on the bottom surface of the substrate layer 1, and the ground layer 2 can be a grounded copper foil, etc. The metallized holes 4 are disposed in the substrate layer 1 and connect the antenna unit 3 and the ground layer 2. Multiple metallized holes 4 are arranged along the periphery of the antenna unit 3. The operating wavelength of the ultra-wideband millimeter-wave antenna based on the PCB board is λ. Among the multiple metallized holes 4 connected to the same antenna unit 3, the spacing between two adjacent metallized holes 4 is less than or equal to 1 / 4λ. In this embodiment, λ is the free space wavelength corresponding to 77 GHz, approximately 0.39 mm.

[0045] Antenna element 3, ground layer 2, and multiple metallized holes 4 densely arranged around the periphery of antenna element 3 form an electromagnetic confinement structure similar to a metal-walled waveguide, limiting the electric field within the waveguide (e.g., a maximum electric field strength of 43723.9 V / m at 74.5 GHz), reducing electromagnetic leakage, and improving energy utilization. This PCB-based ultra-wideband millimeter-wave antenna breaks through the limitations of traditional metal waveguides by utilizing an array of PCB metallized holes 4 to simulate waveguide walls, achieving low-cost electromagnetic confinement. In this embodiment, the edges of the radiating holes 5 adopt a fractal geometry design, which extends the edge current path by 30% and expands the bandwidth to 10 GHz (71-81 GHz) compared to traditional rectangular holes.

[0046] In one or more embodiments, the plurality of radiation holes 5 on the antenna unit 3 are arranged in two staggered rows, that is, any one of the radiation holes 5 in one row corresponds to the gap between two adjacent radiation holes 5 in the other row.

[0047] Optionally, at least one side of the radiation aperture 5 has a plurality of the outward expansion portions 51, with adjacent outward expansion portions 51 spaced apart. In this embodiment, one side of the radiation aperture 5 has two outward expansion portions 51, and the radiation aperture 5 is generally U-shaped. In other embodiments, the radiation aperture 5 can also be of other shapes, which can be adjusted in practice. For example, the side of the radiation aperture 5 with the outward expansion portions 51 may be wavy. The edge of the radiation aperture 5 is designed as a raised wavy shape, a stepped shape, or other shapes, such as a semi-circular protrusion or a sawtooth structure, which realizes the expansion of the operating bandwidth of the PCB-based ultra-wideband millimeter-wave antenna by increasing the current path length at the edge of the radiation aperture 5.

[0048] In this embodiment, the diameter of the metallized hole 4 is 0.2 mm. Preferably, among the multiple metallized holes 4 connected to the same antenna element 3, the spacing between two adjacent metallized holes 4 is 1 / 10λ, that is, the spacing between two adjacent metallized holes 4 is less than or equal to 0.039 mm. Compared with the spacing between two adjacent metallized holes 4 being 1 / 4λ, the shielding efficiency of the spacing between two adjacent metallized holes 4 being 1 / 10λ can be improved by 15%-20%.

[0049] In this embodiment, each antenna element 3 is provided with five radiation holes 5, and there are eight antenna elements 3 in total, forming eight feed ports, of which four feed ports are signal receiving ports and the other four feed ports are signal transmitting ports.

[0050] The antenna unit 3 includes a hole 31 and a conductive part 32, which are far apart from each other. The radiating hole 5 is located in the hole 31. The conductive parts 32 of each antenna unit 3 are close to each other. The conductive parts 32 are used to solder and conduct to the RF chip. The end of the conductive part 32 is the feed port. The position of the feed port can be flexibly adjusted according to the pin layout of the RF chip, supporting MIMO (Multiple Input Multiple Output) technology and meeting the requirements of radar angle measurement or communication diversity. Specifically, at least some of the antenna units 3 have a bent part 33, which is located between the conductive part 32 and the hole 31. The presence of the bent part 33 allows the conductive part 32 to be set more flexibly to adapt to the pin layout of the RF chip. In the actual finished product, a millimeter-wave RF chip, a low-noise amplifier (LNA), and a digital signal processor (DSP) can be integrated simultaneously on the PCB board to form an integrated "antenna-chip-processing" module, which can reduce the size by about 40% compared to traditional solutions.

[0051] The spacing between the apertures 31 of two adjacent antenna elements 3 is 0.5λ-0.8λ. This PCB-based ultra-wideband millimeter-wave antenna can achieve beamforming by controlling the phase difference between antenna elements 3, thereby optimizing the gain of a single antenna element 3 to 14.31dB.

[0052] Figure 4 The image shows the electric field contour plot of the antenna element at 74.5 GHz. Figure 4 The formation and metallized pores with a spacing of 1 / 10λ are clearly shown, from Figure 4 It can be clearly seen that when the antenna unit is working, it can completely confine the electromagnetic waves inside the electromagnetic constraint structure.

[0053] Figure 5 The radiation patterns of the antenna element in the E-plane and H-plane at 77 GHz are shown below. Figure 5 As can be seen, the antenna element has a half-power beamwidth (HPBW) of ≤15° horizontally and ≤20° vertically, with a gain of up to 14.31dB.

[0054] Figure 6 This is a graph showing the S11 parameters of the PCB-based ultra-wideband millimeter-wave antenna in this embodiment. Figure 6 It can be seen that the S11 of this ultra-wideband millimeter-wave antenna is ≤-7.97dB in the 72-81GHz frequency band (80GHz), and S11 is as high as -36.2dB at the 74.5GHz frequency point, with a bandwidth covering 9GHz (relative bandwidth 12.3%).

[0055] Figure 7 This is a graph showing the S21 parameters of the PCB-based ultra-wideband millimeter-wave antenna in this embodiment. Figure 7 It can be seen that this ultra-wideband millimeter-wave antenna exhibits S21≤-32.59dB at the 79.3GHz frequency point, demonstrating high isolation characteristics.

[0056] Application scenario example of this PCB-based ultra-wideband millimeter-wave antenna:

[0057] 1. Automotive radar: Utilizing the high-resolution characteristics of the 77GHz band, it achieves an azimuth accuracy of ≤1° and a range resolution of ≤0.5m for targets 100m away, and supports automatic parking and blind spot detection.

[0058] 2. Industrial security inspection: The ultra-wide bandwidth can penetrate non-metallic materials (such as plastic and wood) to detect internal defects with a resolution of 0.1mm.

[0059] 3.5G millimeter wave communication: supports 8×8 MIMO, data transmission rate ≥10Gbps, and achieves stable connection in mobile scenarios with beamforming technology.

[0060] In summary, this PCB-based ultrawideband millimeter-wave antenna has at least the following advantages:

[0061] 1. Cost advantage: Using PCB mass production technology, the material and processing costs are reduced by 60%-70% compared to traditional metal waveguide solutions, making it suitable for large-scale applications in automotive electronics and consumer electronics.

[0062] 2. Ultra-wideband performance: Frequency coverage of 72-81GHz (9GHz bandwidth), meeting the frequency band requirements of FCC (Federal Communications Commission) and ETSI (European Telecommunications Standards Institute) for 77GHz radar, and supporting multi-mode signal processing.

[0063] 3. High gain and low loss: Through electromagnetic confinement of the metallized aperture array, energy efficiency is improved by 30%, and the gain of a single antenna element can reach 14.31dB, which is 5-8dB higher than that of traditional patch antennas.

[0064] 4. Integration compatibility: Fully compatible with PCB boards, allowing direct integration of RF front-end chips, shortening system design cycle, and reducing size by 50% compared to traditional solutions.

[0065] 5. Process scalability: The metallized via array design can be reused to millimeter-wave bands such as 28GHz and 120GHz. Frequency band migration can be achieved by adjusting the spacing between metallized vias and the thickness of the substrate layer. The technology platform has strong versatility.

[0066] 6. Environmental adaptability: The thermal expansion coefficient of the substrate layer is close to that of the chip package, and the temperature stability is better than that of the metal waveguide solution. The performance fluctuation is <10% within the operating range of -40℃ to 85℃.

[0067] The above are merely optional embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent structural transformations made based on the inventive concept of this utility model and the contents of this utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this utility model.

Claims

1. A PCB-based ultra-wideband millimeter wave antenna, characterized in that: include Substrate layer; Multiple antenna elements are disposed on the top surface of the substrate layer, and the antenna elements are provided with multiple radiation holes, at least one side of the radiation hole having an outwardly expanding portion; A ground layer, wherein the ground layer is disposed on the bottom surface of the substrate layer; Multiple metallized holes are disposed within the substrate layer and connect the antenna unit to the ground layer. The multiple metallized holes are arranged along the periphery of the antenna unit. The operating wavelength of the ultra-wideband millimeter-wave antenna based on the PCB board is λ. Among the multiple metallized holes connected to the same antenna unit, the spacing between two adjacent metallized holes is less than or equal to 1 / 4λ. 2.The PCB-based ultra-wideband millimeter-wave antenna of claim 1, wherein: The multiple radiating holes on the antenna unit are arranged in two staggered rows.

3. The ultra-wideband millimeter-wave antenna based on a PCB board according to claim 1, characterized in that: The radiation aperture has at least one side having a plurality of the outward expansion portions, with adjacent outward expansion portions spaced apart.

4. The PCB-based ultra-wideband millimeter-wave antenna according to claim 3, characterized in that: The radiation hole has two outward expansions on one side, and the radiation hole as a whole is U-shaped.

5. The ultra-wideband millimeter-wave antenna based on a PCB board according to claim 1, characterized in that: The radial aperture has a wavy side on one side of the outward expansion portion.

6. The PCB-based ultra-wideband millimeter-wave antenna according to claim 1, characterized in that: In multiple metallized holes connecting the same antenna element, the spacing between two adjacent metallized holes is 1 / 10λ.

7. The PCB-based ultra-wideband millimeter-wave antenna according to claim 1, characterized in that: The number of antenna elements is eight, and each antenna element is provided with five radiation holes.

8. The ultra-wideband millimeter-wave antenna based on a PCB board according to claim 1, characterized in that: The antenna element includes a hole and a conductive part, the hole and the conductive part are far apart from each other, the conductive parts of each antenna element are close to each other, and the radiation hole is located in the hole.

9. The PCB-based ultra-wideband millimeter-wave antenna according to claim 8, characterized in that: The spacing between the apertures of two adjacent antenna elements is 0.5λ-0.8λ.

10. The PCB-based ultrawideband millimeter-wave antenna according to claim 8, characterized in that: At least a portion of the antenna element has a bent portion located between the conductive portion and the aperture portion.

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