A four-channel OAM antenna for millimeter wave short-range communication

Abstract

The application provides a four-channel OAM antenna for millimeter wave close-range communication, which comprises a microstrip antenna array structure layer, a Butler matrix phased network structure layer, a SICL-based phase delay network structure layer and a quasi-coaxial via hole conversion structure, the quasi-coaxial via hole conversion structure comprises a first feed hole and a second feed hole; the Butler matrix phased network structure layer, the SICL-based phase delay network structure layer and the microstrip antenna array structure layer are sequentially stacked; the end of the microstrip line in the Butler matrix phased network structure layer corresponds to one end of the first feed hole, the first feed hole is vertically extended from the Butler matrix phased network structure layer and corresponds to one end of the substrate integrated coaxial line in the SICL-based phase delay network structure layer; the microstrip antenna array structure layer is provided with microstrip patch antennas, each antenna corresponds to a second feed hole, and the second feed hole is vertically extended and corresponds to the other end of the substrate integrated coaxial line in the SICL-based phase delay network structure layer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of non-contact connector, and in particular to a four-channel OAM antenna for millimeter wave short-range communication. BACKGROUND

[0002] With the rapid development of information technology and the continuous pursuit of high-speed, miniaturization, and high-reliability communication interfaces by electronic equipment, the limitations of the metal contact principle on which traditional electrical connectors are based in high-frequency high-speed applications are increasingly evident. For example, electrical contact surfaces are easily affected by mechanical wear, oxidation, environmental pollution, and other factors, resulting in fluctuations in contact resistance, a decline in signal integrity, and even connection failure. In addition, traditional connectors are prone to stress relaxation, plating wear, corrosion, and other phenomena when faced with complex working conditions such as high insertion frequency, mechanical vibration, and temperature and humidity environments, which seriously affect system stability and lifespan. To overcome the above problems, non-contact connection technology has become a research hotspot in recent years, and new connector schemes based on high-frequency antenna coupling mechanisms in the millimeter wave frequency band (30 GHz-300 GHz) have shown strong application potential. Millimeter wave non-contact connectors use carrier modulation for short-range communication, not only realizing metal-free physical contact, but also utilizing the wide fractional bandwidth of millimeter wave frequencies to support high data rates of gigabits per second (Gbps) at low power consumption and compact architecture, with stronger signal reliability and environmental adaptability, suitable for high-speed consumer electronics, chip-to-board interconnection, industrial intelligent automation, and harsh environment communication scenarios.

[0003] However, despite the significant improvements in physical contact problems of traditional connectors by existing technologies, there are still deficiencies in channel capacity and communication rate. SUMMARY

[0004] In view of this, the embodiments of the present application provide a four-channel OAM antenna for millimeter wave short-range communication to eliminate or improve one or more defects in the prior art.

[0005] One aspect of the present application provides a four-channel OAM antenna for millimeter wave short-range communication, comprising a microstrip antenna array structure layer, a Butler matrix phased network structure layer, a SICL-based phase delay network structure layer, and a quasi-coaxial via conversion structure, the quasi-coaxial via conversion structure comprising a first feed hole and a second feed hole;

[0006] The Butler matrix phased network structure layer, the SICL-based phase delay network structure layer, and the microstrip antenna array structure layer are sequentially stacked and arranged;

[0007] The Butler matrix phased network structure layer is arranged on one side, and the end of the microstrip line in the Butler matrix phased network structure layer corresponds to one end of the first feed hole, the first feed hole extends from the side of the Butler matrix phased network structure layer to the microstrip antenna array structure layer, and corresponds to one end of the substrate integrated coaxial line in the SICL-based phase delay network structure layer;

[0008] The microstrip antenna array structure layer is arranged on the other side, and the microstrip antenna array structure layer is provided with four microstrip patch antennas, each antenna corresponding to a second feed hole, and the second feed hole extends vertically downward from the microstrip antenna array structure layer and corresponds to the other end of the substrate integrated coaxial line in the SICL-based phase delay network structure layer.

[0009] By adopting the above scheme, the scheme is based on a novel four-channel millimeter wave short-distance communication antenna structure based on an Orbital Angular Momentum (OAM) mode multiplexing mechanism, and is suitable for high-speed, high-reliability, non-contact short-distance communication scenarios. By constructing a compact 2x2 microstrip array antenna structure in the 60GHz frequency band and integrating two layers of Butler matrix feed networks, beam generation and multiplexing transmission of four OAM modes of = +1, 0, -1 and ±2 can be realized. l By introducing the Butler matrix, the feed network can provide different continuous phase difference feeds, so as to simultaneously generate or separate multiple OAM modes using the same antenna array. The structure can simultaneously transmit four independent data streams, has the characteristics of compact structure, high mode purity and excellent channel isolation performance, is suitable for integration in short-distance high-speed data transmission scenarios such as non-contact connectors, board-to-board wireless interconnection and precision industrial interfaces, significantly improves the spatial multiplexing capability and data transmission capacity of the system, and provides a practical engineering solution for non-contact millimeter wave connectors.

[0010] Orbital Angular Momentum (OAM) is an angular momentum component carried by electromagnetic waves, which is closely related to the spatial distribution of the electromagnetic waves. The phase has a typical spiral structure, as shown in Figure 13 , which can be represented as exp(jl φ) , wherein l is the mode order, φ is the azimuth angle. OAM modes with different l values are orthogonal in space, which means that they will not interfere with each other, so they can be used as multiple independent channels to simultaneously transmit different data signals, realize "multiplexing on the same frequency", and significantly improve the spectral efficiency and data capacity and rate.

[0011] This design uses l = -1, 0, +1, ±2 four modes are used as four independent channels, which can transmit multiple data streams in the same vertical space using the same antenna array, thus multiplying the system's data throughput and spectral efficiency. Unlike the scheme that uses four different pairs of horn antennas to achieve multiple channels, this scheme uses one pair of antenna arrays in the same space to achieve multiple channels by utilizing the orthogonality of OAM beams.

[0012] OAM beams can be generated using a circular antenna array, such as Figure 14 and 15 As shown, the feed phase difference between adjacent antenna elements is Δ φ = 2 πl / N At that time, a pattern can be generated. l OAM beam.

[0013] In some embodiments of the present invention, the quasi-coaxial via conversion structure further includes a first shielding hole, the first shielding hole being uniformly arranged around the first feed hole, the first shielding hole extending vertically from the Butler matrix phased network structure layer to one side of the microstrip antenna array structure layer, and the height of the first shielding hole being greater than or equal to the first feed hole.

[0014] In the specific implementation, pads are added and metallized vias are drilled between the output port of the Butler matrix and the input port of the SICL phase delay network. Simultaneously, six more vias are added around it to form a quasi-coaxial structure, achieving excellent electromagnetic shielding characteristics. This quasi-coaxial structure extends from the first metal layer through the core board to the sixth metal layer. By rationally designing the outer and inner radii of the quasi-coaxial structure, good impedance matching between the microstrip transmission line and the SICL transmission line can be achieved, while simultaneously shielding against electromagnetic leakage.

[0015] In some embodiments of the present invention, the quasi-coaxial via conversion structure further includes a second shielding hole, which is uniformly arranged along the outer edge of the substrate integrated coaxial line in the SICL-based phase delay network structure layer.

[0016] In some embodiments of the present invention, a first core layer, a second metal layer, a first adhesive layer, a third metal layer, a second core layer, a second adhesive layer, a fourth metal layer, and a third core layer are sequentially disposed between the Butler matrix phased network structure layer and the SICL-based phase delay network structure layer.

[0017] In some embodiments of the present invention, a fifth core board layer, a fourth adhesive layer, a sixth metal layer, a fourth core board layer, and a third adhesive layer are sequentially disposed between the microstrip antenna array structure layer and the SICL-based phase delay network structure layer.

[0018] In some embodiments of the present invention, the first shielding hole extends vertically from the Butler matrix phased network structure layer to the sixth metal layer on one side of the microstrip antenna array structure layer.

[0019] In some embodiments of the present invention, the second shielding hole extends from the fourth metal layer to the sixth metal layer on one side of the microstrip antenna array structure layer.

[0020] In some embodiments of the present invention, the microstrip patch antenna is a rectangular metal sheet.

[0021] Specifically, it is necessary to design the feed network appropriately to provide different fixed phase difference feeds for the microstrip antenna array;

[0022] To generate a pattern l For an OAM wave with a value of 0, four microstrip antenna elements require equal-amplitude and in-phase feeding.

[0023] To generate a pattern l For an OAM wave of 1, a 90° phase difference needs to be satisfied between the four microstrip antenna elements;

[0024] To generate a pattern l For an OAM wave of -1, a phase difference of -90° is required between the four microstrip antenna elements;

[0025] To generate a pattern l For ±2 OAM waves, the four microstrip antenna elements require equal-amplitude, anti-phase feeding, i.e., a phase difference of 180°.

[0026] In some embodiments of the present invention, the Butler matrix phased network structure layer is bonded to the first core board layer, and one end of the microstrip line in the Butler matrix phased network structure layer corresponds to the first feed hole, and the other end extends to the edge of the first core board layer.

[0027] In some embodiments of the present invention, the microstrip line of the Butler matrix phased network structure layer is connected to a 90° hybrid coupler and a 45° phase shifter.

[0028] The above scheme employs a 4×4 Butler matrix based on microstrip transmission lines, consisting of multiple 90° hybrid couplers and phase shifters. By rationally arranging the structure, the problem of increased losses due to cross-connects is avoided. The Butler matrix pattern is located in the first metal layer, with the ground plane as the second layer. Four input ports are distributed on both sides of the Butler matrix. After electromagnetic waves are input, they pass through 90° hybrid couplers to obtain a 0° or 90° phase difference, then pass through a phase shifter to obtain a 45° phase shift, and finally pass through another 90° hybrid coupler to reach the output port. When the four input ports are excited respectively, the four output ports generate four fixed phase differences: +45°, -45°, +135°, and -135°.

[0029] In some embodiments of the present invention, the four substrate-integrated coaxial lines of the SICL-based phase delay network structure layer provide phase shifts of +45°, +90°, +135° and +180°, respectively.

[0030] Additional advantages, objects, and features of the invention will be set forth in part in the description which follows, and will also become apparent in part to those skilled in the art upon studying the text, or may be learned by practice of the invention. The objects and other advantages of the invention will become apparent from the description and the accompanying drawings.

[0031] Those skilled in the art will understand that the objectives and advantages achievable with the present invention are not limited to those specifically described above, and that the above and other objectives achievable with the present invention will become clearer from the following detailed description. Attached Figure Description

[0032] The accompanying drawings, which are provided to further illustrate the invention and form part of this application, are not intended to limit the scope of the invention.

[0033] Figure 1 This is a schematic diagram of the exploded structure of this scheme;

[0034] Figure 2 This is a side view of the structural diagram of this scheme;

[0035] Figure 3 This is a top view of the microstrip antenna array structure layer in this scheme;

[0036] Figure 4 This is a top view schematic diagram of the Butler matrix phased network structure layer in this scheme;

[0037] Figure 5 This is a top view of the phase delay network structure layer based on SICL in this scheme.

[0038] Figure 6 This is a schematic diagram of the quasi-coaxial via conversion structure in this scheme;

[0039] Figure 7 This is a schematic diagram illustrating the working principle of the overall power supply network in this scheme;

[0040] Figure 8 This is a schematic diagram of the simulation results of the phase difference at the output port of the overall power supply network in this scheme;

[0041] Figure 9 This is a schematic diagram of the simulation results of the S-parameters of the overall power supply network transmission coefficient in this scheme;

[0042] Figure 10This is a schematic diagram showing the simulation results of the reflection coefficient of the four-channel OAM antenna in this scheme;

[0043] Figure 11 This is a schematic diagram of the simulation results of the gain pattern of the four-channel OAM antenna in this scheme;

[0044] Figure 12 This is a simulation diagram of the four-channel OAM antenna transmission in this scheme;

[0045] Figure 13 A schematic diagram of the spiral phase of the OAM beam;

[0046] Figure 14 A schematic diagram illustrating the principle of forming an OAM beam for a circular antenna array;

[0047] Figure 15 This is a schematic diagram of an existing 8-element microstrip patch antenna array;

[0048] Figure 16 A schematic diagram of a discrete channel system transmission in the prior art;

[0049] Figure 17 This is a schematic diagram illustrating the transmission process in this scheme.

[0050] Figure 18 This scheme presents the Butler matrix phased network structure diagram. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments and accompanying drawings. Here, the illustrative embodiments and descriptions of this invention are used to explain the invention, but are not intended to limit the invention.

[0052] It should also be noted that, in order to avoid obscuring the invention with unnecessary details, only the structures and / or processing steps closely related to the solution according to the invention are shown in the accompanying drawings, while other details that are not closely related to the invention are omitted.

[0053] Although existing technologies have significantly improved the physical contact issues of traditional connectors, multi-channel parallel communication technology is an inevitable direction for development in order to further enhance channel capacity and communication speed, improve spectrum utilization, and enhance system anti-interference capabilities. Orbital Angular Momentum (OAM) technology provides a completely new dimension for short-range communication systems. For example... Figure 13 As shown, the OAM beam forms multiple orthogonal vortex beams through a spatial spiral phase structure, enabling multi-channel multiplexing within the same space and effectively improving communication capacity per unit area. OAM technology has been widely validated in optical communication and long-range line-of-sight wireless communication, demonstrating its theoretical advantages and engineering feasibility.

[0054] Applying OAM antenna technology to millimeter-wave contactless connector technology, especially for achieving multi-channel parallel high-speed communication over extremely short distances, can significantly improve communication capacity and speed without changing the antenna aperture, representing a breakthrough technological achievement. To date, no multi-channel contactless connector based on OAM technology has been proposed; this solution fills the technological gap in multi-channel communication for contactless connectors.

[0055] like Figure 1 and 2 As shown, this invention proposes a four-channel OAM antenna for millimeter-wave short-range communication, including a microstrip antenna array structure layer, a Butler matrix phased network structure layer, a SICL-based phase delay network structure layer, and a quasi-coaxial via conversion structure, wherein the quasi-coaxial via conversion structure includes a first feed hole and a second feed hole.

[0056] In the specific implementation process, the diameter of both the first and second power supply holes is 0.25mm.

[0057] The Butler matrix phased network structure layer, the SICL-based phase delay network structure layer, and the microstrip antenna array structure layer are stacked sequentially.

[0058] The Butler matrix phased array network structure layer is disposed on one side. The microstrip line end in the Butler matrix phased array network structure layer corresponds to one end of the first feed hole. The first feed hole extends perpendicularly from the Butler matrix phased array network structure layer to one side of the microstrip antenna array structure layer, corresponding to one end of the substrate integrated coaxial line in the SICL-based phase delay network structure layer. Figure 6 As shown;

[0059] The microstrip antenna array structure layer is disposed on the other side. The microstrip antenna array structure layer is arrayed with 4 microstrip patch antennas, each antenna corresponding to a second feed hole. The second feed hole extends vertically downward from the microstrip antenna array structure layer and corresponds to the other end of the substrate integrated coaxial line in the SICL-based phase delay network structure layer.

[0060] like Figure 4 and 18As shown, in the specific implementation, the Butler matrix phased array network structure layer adopts a 4×4 Butler matrix based on microstrip transmission lines, consisting of multiple 90° hybrid couplers and phase shifters. By rationally arranging the structure, the problem of increased losses due to the introduction of cross-connectors is avoided. The Butler matrix pattern is located in the first metal layer at the bottom, with the ground plane as the second layer. Four input ports are distributed on both sides of the Butler matrix. After electromagnetic waves are input, they obtain a 0° or 90° phase difference through the 90° hybrid coupler, a 45° phase shift after passing through the phase shifter, and then reach the output port through another 90° hybrid coupler. When the four input ports are excited respectively, the four output ports generate four fixed phase differences: +45°, -45°, +135°, and -135°.

[0061] like Figure 5 As shown, in the specific implementation, the phase delay network structure layer based on SICL uses a substrate-integrated coaxial line (SICL) as the transmission line, located between the fourth to sixth metal layers of the multilayer core board. It consists of upper and lower ground planes, signal lines, and vias on both sides, effectively suppressing electromagnetic wave leakage and exhibiting high transmission efficiency and low loss. Through reasonable layout and precise line length control, the four output ports of the Butler matrix are connected to the feed positions of the microstrip antenna array, simultaneously providing phase shifts of +45°, +90°, +135°, and +180°. After connection with the Butler matrix, the four output ports can have four fixed phase differences of +90°, 0°, +180°, and -90° in sequential rotation, corresponding to the OAM beam. l= +1 l= 0 、l= -1、 l= ±2 four modes.

[0062] In practical implementation, the overall structure is compressed into a miniaturized area of ​​15mm × 15mm × 1.797mm. Its design meets the electromagnetic performance requirements of 60GHz millimeter-wave communication and fully considers the assembly and packaging compatibility of non-contact connector systems.

[0063] Using the above scheme, this novel four-channel millimeter-wave short-range communication antenna structure based on the Orbital Angular Momentum (OAM) mode multiplexing mechanism is suitable for high-speed, high-reliability, non-contact short-range communication scenarios. By constructing a compact 2×2 microstrip array antenna structure in the 60GHz band and integrating a two-layer Butler matrix feed network, it is possible to achieve… lBeam generation and multiplexing transmission of four OAM modes: +1, 0, -1, and ±2. By introducing the Butler matrix, the feed network can provide different continuous phase difference feeds, thus simultaneously generating or separating multiple OAM modes using the same antenna array. This structure can simultaneously transmit four non-interfering data streams, featuring a compact structure, high mode purity, and excellent channel isolation performance. It is suitable for integration into short-range, high-speed data transmission scenarios such as contactless connectors, board-to-board wireless interconnects, and precision industrial interfaces, significantly improving the system's spatial multiplexing capability and data transmission capacity, providing a practical engineering solution for contactless millimeter-wave connectors.

[0064] This scheme adopts a two-layer power supply network structure, namely:

[0065] First layer: A 4×4 Butler matrix phased network structure based on microstrip lines, used to initially generate four phase gradients;

[0066] The second layer is a phase delay network based on substrate integrated coaxial line (SICL) for further precise phase control, and is connected to the bottom of the antenna array to achieve high-purity OAM mode.

[0067] The two layers are vertically connected by a quasi-coaxial via conversion structure to form a complete three-dimensional power supply path.

[0068] The overall principle of the two-layer feeder network in this design is as follows: Figure 7 As shown. In order to produce the required l =+1、 l =0、 l =-1、 l The OAM orthogonal beamforming with four modes (±2) requires four output ports with four fixed phase differences (+90°, 0°, +180°, and -90°) rotated sequentially.

[0069] The input is port I1, and the phase difference between ports O1, O2, O3, and O4 is 90°.

[0070] The phase difference between ports I2, O1, O2, O3, and O4 is -90°.

[0071] The phase difference between ports I3 and O1, O2, O3, and O4 is 180°.

[0072] The input is port I4, and the phase difference between ports O1, O2, O3, and O4 is 0°.

[0073] In some embodiments of the present invention, the quasi-coaxial via conversion structure further includes a first shielding hole, the first shielding hole being uniformly arranged around the first feed hole, the first shielding hole extending vertically from the Butler matrix phased network structure layer to one side of the microstrip antenna array structure layer, and the height of the first shielding hole being greater than or equal to the first feed hole.

[0074] In the specific implementation, pads are added and metallized vias are drilled between the output port of the Butler matrix and the input port of the SICL phase delay network. Simultaneously, six more vias are added around it to form a quasi-coaxial structure, achieving excellent electromagnetic shielding characteristics. This quasi-coaxial structure extends from the first metal layer through the core board to the sixth metal layer. By rationally designing the outer and inner radii of the quasi-coaxial structure, good impedance matching between the microstrip transmission line and the SICL transmission line can be achieved, while simultaneously shielding against electromagnetic leakage.

[0075] In some embodiments of the present invention, the quasi-coaxial via conversion structure further includes a second shielding hole, which is uniformly arranged along the outer edge of the substrate integrated coaxial line in the SICL-based phase delay network structure layer.

[0076] In some embodiments of the present invention, a first core layer, a second metal layer, a first adhesive layer, a third metal layer, a second core layer, a second adhesive layer, a fourth metal layer, and a third core layer are sequentially disposed between the Butler matrix phased network structure layer and the SICL-based phase delay network structure layer.

[0077] The thickness of the first core board layer is 0.127 mm, the thickness of the second core board layer is 0.508 mm, and the thickness of the third, fourth, and fifth core board layers is 0.254 mm.

[0078] The thickness of the Butler matrix phased network structure layer, the second metal layer, the third metal layer, the fourth metal layer, the SICL-based phase delay network structure layer, the sixth metal layer, and the microstrip antenna array structure layer is all 0.018 mm.

[0079] The Butler matrix phased network structure layer, the SICL-based phase delay network structure layer, and the microstrip antenna array structure layer are respectively used as the first metal layer, the fifth metal layer, and the seventh metal layer.

[0080] In some embodiments of the present invention, a fifth core board layer, a fourth adhesive layer, a sixth metal layer, a fourth core board layer, and a third adhesive layer are sequentially disposed between the microstrip antenna array structure layer and the SICL-based phase delay network structure layer.

[0081] In some embodiments of the present invention, the first shielding hole extends vertically from the Butler matrix phased network structure layer to the sixth metal layer on one side of the microstrip antenna array structure layer.

[0082] In the specific implementation process, the thickness of the first adhesive layer, the second adhesive layer, the third adhesive layer and the fourth adhesive layer is 0.1 mm.

[0083] In some embodiments of the present invention, the first core board layer, the second core board layer, the third core board layer, the fourth core board layer and the fifth core board layer are all made of Rogers 5880 material, and the first adhesive layer, the second adhesive layer, the third adhesive layer and the fourth adhesive layer are all made of Rogers 4450F material.

[0084] In some embodiments of the present invention, the second shielding hole extends from the fourth metal layer to the sixth metal layer on one side of the microstrip antenna array structure layer.

[0085] In the specific implementation process, the diameter of both the first shielding hole and the second shielding hole is 0.2mm.

[0086] In some embodiments of the present invention, the microstrip patch antenna is a rectangular metal sheet.

[0087] like Figure 3 As shown, in the specific implementation process, the microstrip antenna array structure layer of this scheme adopts a uniform circular array structure of four elements. Each microstrip patch antenna is a rectangular structure, which is powered by the underlying SICL feeding structure through a probe. The rectangular microstrip patch antenna is located on the seventh metal layer of the multilayer core board, and the ground plane is the sixth metal layer. A circular hole is cut out in the ground plane to allow the feeding probe to pass through.

[0088] By rationally designing the distances between the four microstrip patch units and the array center, an OAM beam with a specific divergence angle is generated. This structure is intended to generate a mode... l OAM waves require a constant phase difference Δ to be introduced between adjacent antenna elements. φ = 2 π l / N (where N is the total number of array elements, l To generate the desired spiral phase wavefront, a constant amplitude, equal phase difference feed is constructed (for the target OAM mode order). l For an OAM wave with a value of 0, four microstrip patch antenna elements require equal-amplitude, in-phase feeding; to generate a mode... l For an OAM wave of 1, a 90° phase difference is required between the four microstrip patch antenna elements; to generate the mode... l For an OAM wave of -1, a phase difference of -90° is required between the four microstrip patch antenna elements; to generate the mode... l For ±2 OAM waves, the four microstrip patch antenna elements require equal-amplitude, anti-phase feeding, i.e., a phase difference of 180°.

[0089] Specifically, such asFigure 3 As shown, the number of elements N is 4, and the phase difference between the four antenna elements is Δ. φ = 2πl / N When this is done, the OAM beam of mode 1 can be generated. Therefore, to generate the four modes +1, 0, -1, and ±2, the four output ports of the feed network need to be rotated sequentially to provide four phase differences of +90°, 0°, -90°, and 180°.

[0090] In some embodiments of the present invention, the Butler matrix phased network structure layer is bonded to the first core board layer, and one end of the microstrip line in the Butler matrix phased network structure layer corresponds to the first feed hole, and the other end extends to the edge of the first core board layer.

[0091] In some embodiments of the present invention, the microstrip line of the Butler matrix phased network structure layer is connected to a 90° hybrid coupler and a 45° phase shifter.

[0092] like Figure 18 As shown, the system employs four 90° hybrid couplers and two 45° phase shifters, both based on microstrip lines. The 90° hybrid couplers achieve equal-amplitude power division and generate a fixed phase difference of ±90° at the output. Table 1 shows the phase relationships of the four output ports (a, b, c, and d) corresponding to different input ports. After electromagnetic wave input, a 0° or 90° phase difference is obtained through the 90° hybrid couplers, followed by a 45° phase shift through the phase shifters, and then another 90° hybrid coupler before reaching the output port. When the four input ports are excited separately, the four output ports generate four fixed phase differences: +45°, -45°, +135°, and -135°.

[0093] This structure is based on the traditional 4x4 Butler matrix with some improvements. Through reasonable layout, the use of crossbars is avoided, thus avoiding the additional losses and phase errors caused by crossbars. Table 1 discloses the output of this scheme when different input ports are excited.

[0094] Table 1

[0095]

[0096] The above scheme employs a 4×4 Butler matrix based on microstrip transmission lines, consisting of multiple 90° hybrid couplers and phase shifters. By rationally arranging the structure, the problem of increased losses due to cross-connects is avoided. The Butler matrix pattern is located in the first metal layer, with the ground plane as the second layer. Four input ports are distributed on both sides of the Butler matrix. After electromagnetic waves are input, they pass through 90° hybrid couplers to obtain a 0° or 90° phase difference, then pass through a phase shifter to obtain a 45° phase shift, and finally pass through another 90° hybrid coupler to reach the output port. When the four input ports are excited respectively, the four output ports generate four fixed phase differences: +45°, -45°, +135°, and -135°.

[0097] In some embodiments of the present invention, the four substrate-integrated coaxial lines of the SICL-based phase delay network structure layer provide phase shifts of +45°, +90°, +135° and +180°, respectively.

[0098] like Figure 5 As shown, a substrate-integrated coaxial line (SICL) is used as the transmission line, located between the fourth and sixth metal layers of the multilayer core board. It consists of upper and lower ground planes, signal lines, and vias on both sides, effectively suppressing electromagnetic wave leakage and exhibiting high transmission efficiency and low loss. Through reasonable layout and precise line length control, the four output ports of the Butler matrix are connected to the feed positions of the microstrip antenna array, simultaneously providing phase shifts of +45°, +90°, +135°, and +180°. After connection with the Butler matrix, the four output ports can have four fixed phase differences of +90°, 0°, +180°, and -90° in sequential rotation, corresponding to the OAM beam. l= +1 l= 0 、l = -1、 l= The four modes are ±2. Specifically, after the two-layer feed network is vertically connected through the quasi-coaxial via conversion structure, the phase difference provided is shown in Table 2.

[0099] Table 2

[0100]

[0101] The overall power supply network schematic diagram of this solution is as follows: Figure 7 As shown, the S-parameter simulation results are as follows: Figures 8-11 As shown, by precisely setting the transmission line width and length, the phase error of each output port is controlled within ±5°, and the output amplitude error is controlled within 1dB. Figures 8-11 It can be seen that the reflection coefficient of the entire array is less than -10dB in the 58–62GHz range, and the maximum radiation direction gain is about 10dBi.

[0102] To verify the transmission performance and inter-channel isolation of the proposed four-channel OAM antenna in short-range communication, two OAM antennas were placed face-to-face as follows: Figure 12 As shown in Table 3, the simulation results of the transmission coefficients between different modes are presented. When a signal in a certain mode is transmitted, the other three modes at the transmitting end will interfere with it. The transmission coefficient between the same mode minus the transmission coefficient of the interfering mode is the isolation between the channel and the interfering channel. The proposed four-channel OAM antenna has a transmission coefficient of over -16dB for the same mode, and the worst isolation between channels is ≥16dB, with some channels having an isolation exceeding 35dB.

[0103] Table 3

[0104]

[0105] In summary, this solution discloses an Orbital Angular Momentum (OAM) antenna system for short-range high-speed communication. Its core lies in utilizing a ring-shaped microstrip patch antenna and a composite dual-layer feed network structure to achieve efficient OAM mode generation, high inter-mode isolation, and compact packaging. This structure employs a small 2×2 microstrip patch antenna array to generate a vortex OAM beam, achieving precise phase control through an integrated 4×4 Butler matrix, and combining this with a substrate-integrated coaxial line (SICL) structure to achieve low-loss phase shift, forming four orthogonal orbital angular momentum modes, each representing one of four independent communication channels. The system's dual-layer feed network design avoids the loss problems caused by cross-connectors in traditional structures, improving system performance and manufacturing feasibility. The two transmission lines achieve well-matched, low-loss signal transmission through a quasi-coaxial via conversion structure. The overall structure is rationally designed, small in size, has high channel isolation, and is easily integrated into communication modules and contactless connectors, providing crucial support for contactless interconnect devices in the millimeter-wave communication field.

[0106] This invention provides a four-channel orbital angular momentum antenna structure for short-range high-speed communication. By integrating a four-element microstrip patch antenna with a double-layer feed network structure, it proposes the first integrated OAM short-range multi-path transmission antenna system in the 60GHz band.

[0107] Firstly, in terms of communication performance, this technology generates... lThe system utilizes four orthogonal orbital angular momentum modes (-1, 0, +1, ±2) to achieve parallel transmission across four channels at the same frequency, significantly improving system capacity and spectral efficiency, and overcoming the bandwidth bottleneck of traditional single-channel contactless connectors. Secondly, in terms of structural integration, this solution integrates a 2×2 microstrip antenna array, two-layer Butler matrix, and SICL phase-shift network within an extremely small volume of 15mm×15mm×1.797mm. The compact overall layout facilitates packaging in high-density communication modules. Thirdly, regarding isolation and purity performance, the precise layered design of the feed network combined with the SICL structure improves the purity of the generated OAM beam pattern, achieving channel isolation better than 16 dB, with some mode pairs reaching 38 dB, meeting high-reliability communication requirements. Fourthly, in terms of adaptability and application value, this structure is suitable for scenarios with extremely high reliability and packaging requirements, such as inter-board wireless interconnection, intelligent industrial automation, and high-speed consumer electronics connections. It represents a key technological path for contactless connectors towards multi-channel, high-capacity development. In summary, this invention is not only theoretically advanced, but also complete and practical in engineering implementation, providing an efficient and integrable solution for millimeter-wave short-range communication.

[0108] This solution discloses an Orbital Angular Momentum (OAM) antenna system for short-range high-speed communication. Its core lies in utilizing a ring-shaped microstrip patch antenna and a composite dual-layer feed network structure to achieve efficient OAM mode generation, high inter-modal isolation, and compact packaging. The structure employs a small 2×2 microstrip patch antenna array to generate a vortex OAM beam, achieving precise phase control through an integrated 4×4 Butler matrix. Combined with a substrate-integrated coaxial line (SICL) structure, low-loss phase shift is achieved, forming four orthogonal orbital angular momentum modes, each representing one of four independent communication channels. The system's dual-layer feed network design avoids the loss problems caused by cross-connectors in traditional structures, improving system performance and manufacturing feasibility. The two transmission lines achieve well-matched, low-loss signal transmission through a quasi-coaxial via conversion structure. The overall structure is rationally designed, small in size, has high channel isolation, and is easily integrated into communication modules and contactless connectors, providing crucial support for contactless interconnect devices in the millimeter-wave communication field.

[0109] like Figure 14 and 15 As shown, this scheme reduces the number of elements in the circular array to the simplest 4-element circular array, thereby reducing the complexity of the array and feed point network.

[0110] In summary, current research on millimeter-wave contactless connectors focuses on single-channel systems, which cannot further improve data rates and capacity. Existing multi-channel systems also employ discrete channels, with four pairs of antennas for separate transmission and reception, requiring large apertures and structural dimensions. This proposed solution, however, introduces OAM multiplexing technology for millimeter-wave short-range communication, resulting in a multi-channel system with dimensions as shown below. Figure 17 ,contrast Figure 16 Existing solutions are extremely small, measuring only 15mm x 15mm. Furthermore, in existing OAM multiplexing technology research, no highly integrated four-channel antenna operating at close range at 60GHz has been proposed. Some existing multi-channel research results use multiple circular antenna arrays to achieve multiple OAM mode beams, each requiring a feed network. Existing four-channel OAM antennas are large in size, structurally complex, and support a limited number of channels. This design, however, through the introduction of a Butler matrix feed network, can simultaneously generate and separate four OAM modes using the same antenna array and the same feed network.

[0111] While other existing technologies achieve the excitation of different OAM modes using the same feed network through Butler matrices, the feed network and antenna are separate, resulting in low integration and unsuitability for the millimeter-wave short-range communication environment of this design. Figure 7 As shown. This scheme integrates the feed network and antenna array through the ingenious layout of the Butler matrix and the introduction of the SICL layer.

[0112] Finally, this solution is the first to apply the OAM concept to a millimeter-wave multi-channel short-range transmission scenario. Previous OAM designs have mostly been used in long-range line-of-sight propagation environments. This solution, based on orbital angular momentum technology, achieves a multi-channel, high-isolation, and high-reliability millimeter-wave short-range communication system through a precisely designed feed network and compact structure. It not only possesses theoretical advancements but also demonstrates strong practical and integration potential in engineering, representing an important technological direction for the future development of non-contact high-speed connectors.

[0113] Those skilled in the art will understand that the exemplary components, systems, and methods described in conjunction with the embodiments disclosed herein can be implemented in hardware, software, or a combination of both. Whether implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this invention. When implemented in hardware, it can be, for example, electronic circuits, application-specific integrated circuits (ASICs), appropriate firmware, plug-ins, function cards, etc. When implemented in software, the elements of this invention are programs or code segments used to perform the desired tasks. The programs or code segments can be stored in a machine-readable medium or transmitted over a transmission medium or communication link via data signals carried in a carrier wave.

[0114] It should be clarified that the present invention is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of the present invention.

[0115] In this invention, features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, and / or combined with or in place of features of other embodiments.

[0116] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, various modifications and variations of the embodiments of the present invention are possible. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A four-channel OAM antenna for millimeter-wave short-range communication, characterized in that, It includes a microstrip antenna array structure layer, a Butler matrix phased network structure layer, a SICL-based phase delay network structure layer, and a quasi-coaxial via conversion structure, wherein the quasi-coaxial via conversion structure includes a first feed hole and a second feed hole; The Butler matrix phased network structure layer, the SICL-based phase delay network structure layer, and the microstrip antenna array structure layer are stacked sequentially. The Butler matrix phased network structure layer is disposed on one side. The microstrip line end in the Butler matrix phased network structure layer corresponds to one end of the first feed hole. The first feed hole extends vertically from the Butler matrix phased network structure layer to one side of the microstrip antenna array structure layer, corresponding to one end of the substrate integrated coaxial line in the SICL-based phase delay network structure layer. A first core board layer, a second metal layer, a first adhesive layer, a third metal layer, a second core board layer, a second adhesive layer, a fourth metal layer, and a third core board layer are sequentially disposed between the Butler matrix phased network structure layer and the SICL-based phase delay network structure layer. A fifth core board layer, a fourth adhesive layer, a sixth metal layer, a fourth core board layer, and a third adhesive layer are sequentially disposed between the microstrip antenna array structure layer and the SICL-based phase delay network structure layer. The Butler matrix phased network structure layer adopts a 4×4 Butler matrix based on microstrip transmission lines, composed of multiple 90° hybrid couplers and phase shifters, with four input ports distributed... On both sides of the Butler matrix, after electromagnetic waves are input, they obtain a 0° or 90° phase difference through a 90° hybrid coupler, a 45° phase shift after passing through a phase shifter, and then reach the output port through another 90° hybrid coupler. When the four input ports are excited respectively, the four output ports generate four fixed phase differences of +45°, -45°, +135°, and -135°. The phase delay network structure layer based on SICL is located between the fourth to sixth metal layers of the multilayer core board, consisting of upper and lower ground planes, The signal lines and vias on both sides, through reasonable layout and precise line length control, connect the four output ports of the Butler matrix to the feed position of the microstrip antenna array, and simultaneously provide phase shifts of +45°, +90°, +135° and +180°. After being connected to the Butler matrix, the four output ports can have four fixed phase differences of +90°, 0°, +180° and -90° in sequence, corresponding to the four modes of OAM beam: l=+1, l=0, l=-1 and l=±2. The microstrip antenna array structure layer is disposed on the other side. The microstrip antenna array structure layer is arrayed with 4 microstrip patch antennas, each antenna corresponding to a second feed hole. The second feed hole extends vertically downward from the microstrip antenna array structure layer and corresponds to the other end of the substrate integrated coaxial line in the SICL-based phase delay network structure layer.

2. The four-channel OAM antenna for millimeter-wave short-range communication according to claim 1, characterized in that, The quasi-coaxial via conversion structure also includes a first shielding hole, which is uniformly arranged around the first feed hole. The first shielding hole extends vertically from the Butler matrix phased network structure layer to one side of the microstrip antenna array structure layer, and the height of the first shielding hole is greater than or equal to that of the first feed hole.

3. The four-channel OAM antenna for millimeter-wave short-range communication according to claim 2, characterized in that, The quasi-coaxial via conversion structure further includes a second shielding hole, which is uniformly arranged along the outer edge of the substrate integrated coaxial line in the SICL-based phase delay network structure layer.

4. The four-channel OAM antenna for millimeter-wave short-range communication according to claim 2, characterized in that, The first shielding hole extends vertically from the Butler matrix phased network structure layer to the sixth metal layer on one side of the microstrip antenna array structure layer.

5. The four-channel OAM antenna for millimeter-wave short-range communication according to claim 3, characterized in that, The second shielding hole extends vertically from the fourth metal layer to one side of the microstrip antenna array structure layer to the sixth metal layer.

6. The four-channel OAM antenna for millimeter-wave short-range communication according to claim 1, characterized in that, The Butler matrix phased network structure layer is attached to the first core board layer. One end of the microstrip line in the Butler matrix phased network structure layer corresponds to the first feed hole, and the other end extends to the edge of the first core board layer.

7. The four-channel OAM antenna for millimeter-wave short-range communication according to claim 1, characterized in that, The microstrip lines of the Butler matrix phased network structure layer are connected to a 90° hybrid coupler and a 45° phase shifter.

8. The four-channel OAM antenna for millimeter-wave short-range communication according to claim 1, characterized in that, The four substrate-integrated coaxial lines of the SICL-based phase delay network structure layer provide phase shifts of +45°, +90°, +135°, and +180°, respectively.

Images