Millimeter wave single-layer broadband slant phased array antenna

Abstract

The application discloses a millimeter wave single-layer broadband inclined phased array antenna, which comprises a dielectric substrate (14), a first antenna radiation unit (1), a second antenna radiation unit (2), a third antenna radiation unit (3) and a fourth antenna radiation unit (4) formed by top and bottom metal layers (13) and (15) arranged on two sides of the dielectric substrate; the four antenna radiation units are arranged in an array in a one-dimensional direction and are arranged in a 1*4 linear array in a horizontal direction of an H plane; equal-amplitude and unequal-phase feed is input into feed ports of the four antenna radiation units to obtain the beam scanning characteristic of the H plane of the antenna array; and the antenna array uses a technical means of superimposing a broadside beam and an end-fire beam to realize a stable 45-degree inclined beam in a wide working frequency band. In addition, equal-amplitude and unequal-phase feed is provided for the feed ports of the first to fourth radiation units to obtain the beam scanning characteristic of the H plane.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication, and specifically relates to a millimeter-wave single-layer broadband oblique phased array antenna. Background Technology

[0002] The development and utilization of new spectrum resources are crucial for driving the advancement of wireless communication technology. To date, with the adoption of millimeter-wave technology in fifth-generation (5G) communication, global data transmission rates have significantly increased, spurring extensive research and implementation of millimeter-wave antenna arrays and transceivers. Compared to frequencies below 6 GHz, millimeter-wave radiated waves exhibit greater path loss during propagation in space. Phased array antennas can effectively concentrate the radiated energy of the antenna array in a predetermined direction while ensuring spatial coverage, making them a promising technology for mitigating the effects of high path loss. Due to their high switching speed, high flexibility, and superior performance, phased array antennas have been widely used in millimeter-wave communication.

[0003] Tilted beam antennas have significant application potential in base stations, vehicle-mounted terminals, and handheld terminals, enhancing coverage and communication quality and distance to some extent, and have received widespread attention in recent years. Various techniques, such as external reflectors, directional antennas, and phase gradient surfaces, are used to adjust the antenna's propagation direction. However, these solutions significantly increase the antenna's footprint and size, hindering array integration and formation. Furthermore, their narrow bandwidth makes it difficult to cover multiple 5G millimeter-wave communication bands. Therefore, as wireless communication systems continue to evolve towards miniaturization and integration, designing substrate-integrated millimeter-wave phased arrays with wide bandwidth, compact design, and custom tilt angles is an urgent goal.

[0004] Antennas developed on single-layer substrates have simple structures that are easy to integrate, reducing system cost and complexity and facilitating large-scale deployment and application. Furthermore, broadband antennas can improve signal bandwidth and frequency response, enabling high-speed, high-capacity data transmission. Although broadband side-fire phased array antennas have received considerable attention in recent years, achieving broadband characteristics on a single-layer structure remains challenging due to limitations in feed network design. Meanwhile, some broadband or single-layer millimeter-wave end-fire antennas have been reported. However, end-fire antennas still face the challenge of balancing profile height and impedance bandwidth, making it difficult to realize broadband end-fire antennas on single-layer substrates or low-profile structures. Therefore, research on broadband millimeter-wave antennas based on single-layer substrates has significant theoretical and practical value. Summary of the Invention

[0005] Technical Problem: The purpose of this invention is to address the immaturity of existing technical solutions by providing a millimeter-wave single-layer broadband oblique-fire phased array antenna. This antenna achieves broadband operation on a single-layer dielectric substrate and, without adding additional parasitic structures, maintains stable 45° oblique radiation beam performance over a wide bandwidth. Structurally, it offers advantages such as low profile, lightweight materials, and ease of integration with RF circuits.

[0006] Technical Solution: To achieve the above objectives, this invention provides a millimeter-wave single-layer broadband oblique-fire phased array antenna. This phased array antenna comprises a dielectric substrate and a first antenna radiating element, a second antenna radiating element, a third antenna radiating element, and a fourth antenna radiating element, formed by a top metal layer and a bottom metal layer disposed on both sides of the dielectric substrate. The first, second, third, and fourth antenna radiating elements are arrayed in a one-dimensional direction, arranged laterally in a 1*4 linear array on their H-plane (the plane containing the electric field intensity vector of the antenna radiation field and including the direction of maximum radiation). The dielectric substrate between adjacent radiating elements is cut with a first long groove, a second long groove, and a third long groove, forming air gaps. By inputting equal-amplitude but unequal-phase feeds into the feed ports of the first, second, third, and fourth antenna radiating elements, the beam scanning characteristics of the antenna array's H-plane are obtained.

[0007] The first antenna radiating element, the second antenna radiating element, the third antenna radiating element, and the fourth antenna radiating element have the same structure. Each antenna radiating element includes a rectangular waveguide aperture antenna composed of a rectangular substrate integrated waveguide. The rectangular substrate integrated waveguide is provided with a feed structure for coaxial-substrate integrated waveguide transition and a pair of monopoles, namely the first monopole and the second monopole. The rectangular substrate integrated waveguide forms an aperture radiation at the end opening. The dielectric substrate at the opening end is extended. The top of the pair of monopoles is respectively loaded with a first circular patch and a second circular patch and disposed on the extended dielectric substrate.

[0008] A transverse slot is provided on the bottom metal layer of the rectangular substrate integrated waveguide, and the transverse slot is located near the opening side of the substrate integrated waveguide; the shape of the transverse slot is set to "H".

[0009] The rectangular substrate integrated waveguide comprises a U-shaped grounding metallized hole array consisting of a first grounding metallized hole array, a second grounding metallized hole array, and a third grounding metallized hole array. A coaxial-substrate integrated waveguide transition feeding structure is provided at the far end of the rectangular substrate integrated waveguide away from the opening end, i.e., the bottom wide side metal wall, for feeding. The rectangular substrate integrated waveguide is sealed with the third grounding metallized hole array to prevent signal leakage, thereby forming a rectangular waveguide opening antenna.

[0010] The pair of monopoles, namely the first monopole and the second monopole, are composed of two metallized vias, namely the first metallized via and the second metallized via. The top ends of the two metallized vias are respectively connected to the first circular patch and the second circular patch. The bottom ends of the two metallized vias are respectively connected to a pair of short stubs on the bottom metal layer, namely the first short stub and the second short stub, to feed the monopoles. The first circular patch and the second circular patch loaded on the top of the monopole are not connected to the top metal layer of the rectangular substrate integrated waveguide, and the current on the first circular patch and the second circular patch is connected to the bottom metal layer of the rectangular substrate integrated waveguide through the monopole, so that the current distribution on the surfaces of the two are in phase.

[0011] The coaxial-substrate integrated waveguide adapter structure includes a coaxial probe consisting of a metallized via connecting a first circular pad on the top layer and a second circular pad on the bottom layer. The metallized via forming the coaxial probe is filled with grout and electroplated to create a plug. The diameters of the first circular pad and the second circular pad on the bottom layer are slightly larger than the diameter of the metallized via.

[0012] The coaxial probe is not directly connected to the top metal layer and the bottom metal layer. In the top metal layer and the bottom metal layer, at the position corresponding to the coaxial probe, there are a first cutout area and a second cutout area with a diameter larger than the projection of the coaxial probe pad, i.e., the first circular pad and the second circular pad.

[0013] The upper part of the coaxial probe is also connected to a first coaxial connector, a second coaxial connector, a third coaxial connector, and a fourth coaxial connector. The outer conductor of the coaxial connector is connected to the wide wall of the top metal layer of the substrate integrated waveguide, and the inner conductor of the coaxial connector is connected to the first circular pad of the metallized via that constitutes the coaxial probe.

[0014] Beneficial effects: By adopting the above scheme, the millimeter-wave single-layer broadband oblique-fire phased array antenna provided by this invention can achieve broadband characteristics on a single-layer dielectric substrate using the multimode resonance principle. Furthermore, without adding additional parasitic structures, by utilizing the principle of superimposing the side-emitting and end-emitting radiating apertures, stable 45° oblique radiation performance can be achieved within a wide operating frequency band. Moreover, this phased array has the advantages of low profile, lightweight materials, and ease of integration with RF circuits. Attached Figure Description

[0015] Figure 1 This is a three-dimensional schematic diagram of the phased array provided by the present invention;

[0016] Figure 2 This is a top view of the phased array provided by the present invention;

[0017] Figure 3 This is a diagram of the stacked structure of the phased array provided by the present invention;

[0018] Figure 4 This is a three-dimensional schematic diagram of the radiating element of the phased array provided by the present invention;

[0019] Figure 5 This is a schematic diagram of the location of the metal vias in the radiation unit of the phased array provided by the present invention;

[0020] Figure 6 This is a schematic diagram of the top metal structure of the radiation unit of the phased array provided by the present invention;

[0021] Figure 7 This is a schematic diagram of the bottom metal structure of the radiating unit of the phased array provided by the present invention;

[0022] Figure 8 A cross-sectional schematic diagram of the coaxial-substrate integrated waveguide structure of the radiating element of the phased array provided by the present invention;

[0023] Figure 9 The present invention provides simulation and test results of the radiation patterns of a single radiating element of a phased array at 27 GHz and 35 GHz, including the E-plane (the plane containing the magnetic field strength vector of the antenna radiation field and including the maximum radiation direction) and the H-plane (the plane containing the electric field strength vector of the antenna radiation field and including the maximum radiation direction).

[0024] Figure 10 The present invention provides simulation and test results of the gain of a single radiating element of a phased array as a function of frequency in the 45° oblique direction.

[0025] Figure 11 Simulation and test results of port reflection parameters of phased array provided by this invention;

[0026] Figure 12 The present invention provides simulation and test results of the port isolation of the phased array;

[0027] Figure 13 The present invention provides simulation and test results of H-plane beam scanning of phased arrays at 27 GHz and 35 GHz.

[0028] This includes: a first antenna radiating element 1, a second antenna radiating element 2, a third antenna radiating element 3, a fourth antenna radiating element 4, a feed structure 5, a first coaxial connector 6, a second coaxial connector 7, a third coaxial connector 8, a fourth coaxial connector 9, a first long trench 10, a second long trench 11, a third long trench 12, a top metal layer 13, a dielectric substrate 14, a bottom metal layer 15, a rectangular waveguide aperture antenna 16, a first monopole 17, a second monopole 18, and a lateral slot 19. 20. Grounding metallized via array, 21. Grounding metallized via array, 22. Grounding metallized via array, 23. First metallized via, 24. Second metallized via, 25. First circular patch, 26. Second circular patch, 27. First stub, 28. Second stub, 29. Bottom wide-edge metal wall, 30. Coaxial probe, 31. First circular pad, 32. Second circular pad, 33. First cutout area, 34. Second cutout area, 35. Coaxial connector outer conductor, 36. Coaxial connector inner conductor. Detailed Implementation

[0029] The technical solution and beneficial effects of the present invention will be described in detail below with reference to the accompanying drawings.

[0030] like Figure 1 This embodiment describes a millimeter-wave single-layer broadband oblique phased array antenna.

[0031] Reference Figure 1 and Figure 2 The phased array antenna of this embodiment includes a first antenna radiating element 1, a second antenna radiating element 2, a third antenna radiating element 3, a fourth antenna radiating element 4, and a coaxial-substrate integrated waveguide feed structure 5, all printed on both sides. The radiating elements are translated and replicated laterally with a period of 6 mm to obtain four radiating elements, which form an array in one dimension. Adjacent radiating elements do not share a row of metallized vias in the substrate integrated waveguide to improve port isolation between adjacent radiating elements. A first coaxial connector 6, a second coaxial connector 7, a third coaxial connector 8, and a fourth coaxial connector 9 are soldered onto the coaxial-substrate integrated waveguide feed structure of the four radiating elements. By inputting equal-amplitude but unequal-phase feeds at the coaxial connector feed ports of the first to fourth radiating elements, the beam scanning characteristics of the H-plane of the antenna array can be obtained. Simultaneously, the dielectric substrate between the phased array radiating elements is cut with a first long groove 10, a second long groove 11, and a third long groove 12, forming air gaps to further improve the isolation between adjacent radiating elements.

[0032] Reference Figure 3The phased array antenna in this embodiment is manufactured using printed circuit board technology. The side cross-section, from top to bottom, shows a top metal layer 13, a dielectric substrate 14, and a bottom metal layer 15. The single-layer dielectric substrate eliminates the need for multi-layer board lamination, resulting in a simple structure that significantly reduces antenna manufacturing costs and minimizes error risks during processing, thus ensuring high reliability in testing and practical applications of the phased array antenna.

[0033] Figure 4 The radiating element of the phased array antenna in this embodiment includes a rectangular waveguide aperture antenna 16, a pair of monopoles, namely a first monopole 17 and a second monopole 18, and a transverse slot 19 etched on the wide side of the bottom surface of the substrate integrated waveguide. The substrate integrated waveguide forms an aperture-area radiation at its end opening, and the dielectric substrate at the opening end is extended by a certain dimension to optimize impedance matching. A pair of monopoles with circular patches loaded at their tops are disposed on the extended dielectric substrate; the circular patches can extend the current path of the monopoles, thereby reducing the electrical size of the monopoles. A transverse slot is etched on the wide metal wall of the substrate integrated waveguide on the underlying metal. The waveguide aperture antenna can effectively excite the monopole mode and the slot mode, forming the wideband characteristics of the antenna under multimode excitation.

[0034] like Figure 5 The substrate integrated waveguide of the radiating unit is composed of two rows of grounded metallized hole arrays, namely the first grounded metallized hole array 20 and the second grounded metallized hole array 21. A coaxial-substrate integrated waveguide transition structure is provided on one side of the rectangular substrate integrated waveguide for power feeding, and a row of third grounded metallized hole array 22 is used to close the substrate integrated waveguide to prevent signal leakage. The other side of the rectangular substrate integrated waveguide is set as an opening to form a rectangular waveguide opening antenna 16.

[0035] like Figure 5 , 6 7. The radiating element employs a pair of monopoles with top-loaded circular patches disposed on the extended dielectric of the substrate integrated waveguide. Two metallized vias, namely the first metallized via 23 and the second metallized via 24, constitute a pair of monopoles. A pair of circular patches, namely the first circular patch 25 and the second circular patch 26, are printed on the top metal layer and connected to the monopoles formed by the metallized vias. A pair of stub lines, namely the first stub line 27 and the second stub line 28, are printed on the bottom metal layer to connect the monopoles to the bottom wide-side metal wall 29 of the substrate integrated waveguide for feeding the monopoles.

[0036] like Figure 7 In the radiating element, a transverse slot 19 is etched on the bottom metal wide wall 29 of the substrate integrated waveguide and is at a certain distance from the opening side of the substrate integrated waveguide; the shape of the transverse slot is set to "H" shape to optimize impedance matching within the antenna operating frequency band.

[0037] like Figure 8 The coaxial-substrate integrated waveguide transition structure of the radiating element is located on the other side of the rectangular substrate integrated waveguide aperture antenna. The coaxial probe 30 is formed by a metallized via connecting the top and bottom metal layers. Its position is located at the exact center of the wide side of the substrate integrated waveguide and a certain distance from the closed side metal wall of the substrate integrated waveguide. The metallized via constituting the coaxial probe is filled with grout and electroplated to create a plug hole. A first circular pad 31 and a second circular pad 32, slightly larger than the diameter of the metallized via, are provided on the top and bottom metal layers.

[0038] like Figure 6 , 7 The coaxial probe is not directly connected to the top and bottom metals that constitute the wide side metal wall of the substrate integrated waveguide. In the top and bottom metals, corresponding to the position of the coaxial probe, there are a first cutout area 33 and a second cutout area 34 with an area larger than the projection of the coaxial probe pad to avoid grounding short circuit of the feed line.

[0039] like Figure 8 The outer conductor 35 of the coaxial connector of the radiating unit is soldered to the top metal wide wall of the substrate integrated waveguide, and the inner conductor 36 of the coaxial connector is soldered to the top circular pad of the metallized via that constitutes the coaxial probe.

[0040] To verify the authenticity and reliability of the single-layer broadband oblique-fire phased array antenna provided by this invention, a 1*4 phased array antenna example operating in the Ka band was fabricated according to the technical solution provided by this invention for verification. The designed example phased array antenna uses a Rogers 4003C dielectric substrate with a thickness of 1.524mm. Figures 9 to 13 The simulation results and actual test parameters of the example antenna element and array are presented. The simulation and experimental results show that the phased array antenna has the advantages of simple structure, wide bandwidth, stable oblique radiation and good H-plane beam scanning performance.

[0041] The above description is merely a preferred embodiment of the present invention, used to illustrate the technical concept of the present invention, and should not be construed as limiting the scope of protection of the present invention. Any modifications made without departing from the principle of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A millimeter-wave single-layer broadband oblique-fire phased array antenna, characterized in that: The phased array antenna comprises a dielectric substrate (14) and a first antenna radiating element (1), a second antenna radiating element (2), a third antenna radiating element (3), and a fourth antenna radiating element (4) formed by a top metal layer (13) and a bottom metal layer (15) disposed on both sides of the dielectric substrate; wherein, the first antenna radiating element (1), the second antenna radiating element (2), the third antenna radiating element (3), and the fourth antenna radiating element (4) are arrayed in one dimension and arranged in a horizontal sequence on its H plane to form a 1*4 linear array; the dielectric substrate (14) between each adjacent radiating element is cut with a first long groove (10), a second long groove (11), and a third long groove (12) to form an air gap; by inputting equal amplitude but unequal phase feeds into the feed ports of the first antenna radiating element (1), the second antenna radiating element (2), the third antenna radiating element (3), and the fourth antenna radiating element (4), the beam scanning characteristics of the H plane of the antenna array are obtained; The first antenna radiating unit (1), the second antenna radiating unit (2), the third antenna radiating unit (3), and the fourth antenna radiating unit (4) have the same structure. Each antenna radiating unit contains a rectangular waveguide aperture antenna (16) composed of a rectangular substrate integrated waveguide. A feed structure (5) for coaxial-substrate integrated waveguide transition and a pair of monopoles, namely the first monopole (17) and the second monopole (18), are provided in the rectangular substrate integrated waveguide. The rectangular substrate integrated waveguide forms an aperture surface radiation at the end opening. The dielectric substrate (14) at the opening end is extended. The top of the pair of monopoles is loaded with a first circular patch (25) and a second circular patch (26) respectively and is placed on the extended dielectric substrate (14). The pair of monopoles, namely the first monopole (17) and the second monopole (18), are composed of two metallized vias, namely the first metallized via (23) and the second metallized via (24). The top ends of the two metallized vias are respectively connected to the first circular patch (25) and the second circular patch (26). The bottom ends of the two metallized vias are respectively connected to a pair of short lines on the bottom metal layer (15), namely the first short line (27) and the second short line (28), to feed the monopoles. The first circular patch (25) and the second circular patch (26) loaded on the top of the monopole are not connected to the top metal layer (13) of the rectangular substrate integrated waveguide. The current on the first circular patch (25) and the second circular patch (26) is connected to the bottom metal layer of the rectangular substrate integrated waveguide through the monopole, so that the current distribution on the surface of the two is in phase.

2. The millimeter-wave single-layer broadband oblique-fire phased array antenna as described in claim 1, characterized in that: The rectangular substrate integrated waveguide is composed of a U-shaped grounding metallized hole array consisting of a first grounding metallized hole array (20), a second grounding metallized hole array (21), and a third grounding metallized hole array (22). A coaxial-substrate integrated waveguide transition feeding structure (5) is provided on the far end of the rectangular substrate integrated waveguide away from the opening end, i.e., the bottom wide side metal wall (29), for feeding. The rectangular substrate integrated waveguide is closed by the third grounding metallized hole array (22) to prevent signal leakage, so as to form a rectangular waveguide opening antenna.

3. The millimeter-wave single-layer broadband oblique-fire phased array antenna as described in claim 2, characterized in that: A transverse slot (19) is provided on the bottom metal layer (15) of the rectangular substrate integrated waveguide. The transverse slot (19) is located near the opening side of the substrate integrated waveguide. The shape of the transverse slot is set to "H".

4. The millimeter-wave single-layer broadband oblique-fire phased array antenna as described in claim 1, characterized in that: The coaxial-substrate integrated waveguide feed structure (5) includes a coaxial probe (30) consisting of a metallized via connecting a first circular pad (31) on the top layer and a second circular pad (32) on the bottom layer. The metallized via forming the coaxial probe is filled with grout and electroplated to form a plug hole. The diameters of the first circular pad (31) and the second circular pad (32) on the bottom layer are slightly larger than the diameter of the metallized via.

5. A millimeter-wave single-layer broadband oblique-fire phased array antenna as described in claim 4, characterized in that: The coaxial probe (30) is not directly connected to the top metal layer (13) and the bottom metal layer (15). In the top metal layer (13) and the bottom metal layer (15), at the position corresponding to the coaxial probe (30), there is a first hollow area (33) and a second hollow area (34) with a diameter larger than the projection of the coaxial probe pad, i.e., the first circular pad (31) and the second circular pad (32).

6. A millimeter-wave single-layer broadband oblique-fire phased array antenna as described in claim 5, characterized in that: The upper part of the coaxial probe (30) is also connected to a first coaxial connector (6), a second coaxial connector (7), a third coaxial connector (8), and a fourth coaxial connector (9). The outer conductor (35) of the coaxial connector is connected to the wide wall of the top metal layer (13) of the substrate integrated waveguide, and the inner conductor (36) of the coaxial connector is connected to the first circular pad (31) of the metallized via that constitutes the coaxial probe.

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