A compactly arranged terahertz phased array antenna and a combined phased array antenna

Abstract

This invention belongs to the field of terahertz communication, specifically a compactly arranged terahertz phased array antenna and a combined phased array antenna. Each antenna element of this phased array antenna is fed by a substrate-integrated coaxial line. Radiation and coupling are achieved through a slot structure on the upper metal layer, exciting the slot structure and two side-by-side mirror-arranged trapezoidal patches above it, making it equivalent to a magnetoelectric dipole antenna. This effectively overcomes the problems of high-order modes and severe surface waves caused by the low dielectric constant and thick substrate in the terahertz band, exhibiting excellent radiation characteristics with low return loss and a wide-bandwidth beam. By connecting a rectangular slot extending to one edge of the middle metal layer to each end of the open annular slot in the first substrate-integrated coaxial line feeding structure, the port is located on one side of the overall structure, facilitating a compact array arrangement and feeding structure lead-out. This design is suitable for the integrated and compact design of two-dimensional beam-scanning phased array antenna sections.

Description

Technical Field

[0001] This invention belongs to the field of terahertz communication, specifically a compactly arranged terahertz phased array antenna and a combined phased array antenna. Background Technology

[0002] Terahertz waves refer to electromagnetic waves with frequencies ranging from 0.1 THz to 10 THz and wavelengths between 0.03 mm and 3 mm. They possess characteristics between microwaves and infrared waves, exhibiting low quantum energy, wide bandwidth, and good penetration, making them suitable for applications such as biological imaging, rapid THZ spectrum detection, high-speed communication, and through-wall radar. With the deepening research into terahertz technology, terahertz-related devices and antennas have gradually become research hotspots. Within the terahertz frequency band, the area around 220 GHz represents a communication atmospheric window suitable for high-speed communication systems. However, because terahertz signals attenuate significantly in the atmosphere, their transmission distance is inherently shorter than that of microwaves for the same radiated power; therefore, high-gain antenna systems are required to combat path loss.

[0003] A phased array antenna is a complex system with integrated functions. By adding active electrically tunable devices such as amplifiers and phase shifters to the back end of a passive antenna array, amplitude and phase control of each antenna is achieved, enabling high gain, low sidelobes, and fast beam scanning. It is widely used in various radar and communication systems. To ensure large-angle beam scanning capability and suppress grating lobes, the array spacing of the antenna array is generally less than half the operating wavelength. In the limited array space, the back end of each antenna needs to be connected to a relatively complex active feed network. In the microwave band, there are many mature solutions for this, but in the terahertz band, due to factors such as process conditions, substrate thickness, loss characteristics, and active devices, there are many problems such as complex structure, difficulty in further miniaturization, and low integration.

[0004] For example, Chinese patent CN115548702A discloses a millimeter-wave terahertz one-dimensional phased array antenna. The antenna is a substrate-integrated waveguide slot antenna array, which arranges multiple slot antenna arrays side by side to achieve beam scanning in the array direction. However, the proposed phased array is limited by the antenna form and complex feeding network, making it impossible to further achieve two-dimensional beam scanning.

[0005] For example, Chinese patent CN111244624A discloses a parasitic patch array antenna fed by a substrate integrated waveguide, which has the advantages of low profile, small size, and easy planar circuit integration. However, this antenna array only has one centimeter feed, the antenna beam is fixed, and beam scanning is not possible.

[0006] For example, Chinese patent CN116895951A discloses a compact high-gain terahertz diagonal horn array antenna, which features wide bandwidth, high gain, compact structure, high aperture space utilization, and low sidelobes and grating lobes. However, this antenna array is also fed by a centimeter network, which can only generate a fixed beam and cannot perform scanning. In addition, the complex waveguide feeding network poses a significant challenge to the fabrication process. Summary of the Invention

[0007] The purpose of this invention is to provide a compactly arranged terahertz phased array antenna and a combined phased array antenna, which has the advantages of simple structure, compactness, ease of processing, and high integration, and is suitable for two-dimensional beam scanning.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A compactly arranged terahertz phased array antenna includes an antenna array structure, a substrate coaxial feed network, and a transition connection network; the antenna array structure is connected to the transition connection network through the substrate coaxial feed network.

[0010] The antenna array structure includes multiple antenna element structures arranged in m rows × n columns. Each antenna element structure includes a first substrate integrated coaxial feed structure and an antenna body. The antenna body is stacked above the first substrate integrated coaxial feed structure and includes an upper metal layer and an upper dielectric layer stacked on the upper metal layer. The upper dielectric layer has multiple first metallized vias penetrating the upper and lower surfaces along the circumferential direction. Its upper surface has an annular metal sheet and a radiating element. The annular metal sheet is located directly above the first metallized vias. The radiating element is located inside the annular metal sheet and includes two trapezoidal patches. The two trapezoidal patches are arranged side by side in a mirror image with a gap between them. The upper metal layer has a slot structure corresponding to the gap between the two trapezoidal patches.

[0011] Furthermore, the first substrate integrated coaxial cable feeding structure includes a lower metal layer, a lower dielectric layer, an intermediate metal layer, an intermediate dielectric layer, and an upper metal layer stacked sequentially from bottom to top;

[0012] The intermediate metal layer is provided with a groove structure and a second metallized via through the metal layer; the groove structure is used to isolate the outer conductor and the inner conductor, and is an open annular groove, with a rectangular groove extending to one side edge of the intermediate metal layer at each end of the opening; the second metallized via is arranged circumferentially along the groove structure and is located outside the groove structure, with its top penetrating the intermediate dielectric layer and its bottom penetrating the lower dielectric layer.

[0013] Furthermore, the annular metal sheet is a square annular metal sheet; the open annular groove is an open square annular groove.

[0014] Furthermore, the slit structure is a rectangular slit structure.

[0015] Furthermore, the transition connection network consists of multiple transition structures, each of which includes a second substrate integrated coaxial line and a rectangular waveguide. The second substrate integrated coaxial line is similar in structure to the first substrate integrated coaxial line, except that the inner conductor of the second substrate integrated coaxial line is provided with a coupling patch and a matching stub. The coupling patch is located on the lower metal layer, and the matching stub is located on the middle metal layer, with the matching stub aligned vertically with the coupling patch. The rectangular waveguide is coupled to the second substrate integrated coaxial line through the coupling patch.

[0016] Furthermore, the lower dielectric layer, the intermediate dielectric layer, and the upper dielectric layer are all quartz dielectric substrates.

[0017] A compactly arranged terahertz phased array antenna consists of multiple pairs of the aforementioned compactly arranged terahertz phased array antennas arranged in a mirror array.

[0018] This invention provides a compact terahertz phased array antenna, composed of multiple antenna element structures arranged in m rows × n columns. Each antenna element structure is fed by a substrate-integrated coaxial line. Radiation and coupling are achieved through a slot structure on the upper metal layer, exciting the slot structure and two side-by-side mirror-arranged trapezoidal patches above it, making it equivalent to a magnetoelectric dipole antenna. This effectively overcomes the problems of high-order modes and severe surface waves caused by the low dielectric constant and thick substrate in the terahertz band, exhibiting excellent radiation characteristics with low return loss and a wide-bandwidth beam. Isolation is improved by introducing a grounding ring-shaped metal sheet into the antenna element structure. By connecting a rectangular slot extending to one edge of the middle metal layer to each end of the open ring slot in the first substrate-integrated coaxial line feeding structure, the port is located on one side of the overall structure, facilitating a compact array arrangement and feeding structure lead-out. This design is suitable for the integrated and compact design of two-dimensional beam-scanning phased array antenna sections.

[0019] Furthermore, the design of a transition connection structure solved the problem of complex transmission path layout caused by the front-end active circuit being much larger than the antenna array, simplifying the manufacturing process. By adding matching stubs and coupling patches to the inner conductor of the substrate-integrated coaxial line in the transition structure, low-loss terahertz wave transmission was ensured. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a compactly arranged terahertz phased array antenna model for an embodiment.

[0021] Figure 2 A cross-sectional view of a compactly arranged terahertz phased array antenna as shown in the embodiment;

[0022] Figure 3The antenna element structure model diagram of the compactly arranged terahertz phased array antenna for the embodiment is shown.

[0023] Figure 4 An exploded view of the antenna element structure of a compactly arranged terahertz phased array antenna as an example;

[0024] Figure 5 A model diagram of the internal feed layer of the antenna element structure of the compactly arranged terahertz phased array antenna in the embodiment;

[0025] Figure 6 This is a model diagram of an antenna array formed by arranging antenna elements in a 4×4 configuration, as shown in the example.

[0026] Figure 7 An exploded view of an antenna array formed by arranging antenna elements in a 4×4 configuration, as shown in the example.

[0027] Figure 8 A model diagram of the transition structure of a compactly arranged terahertz phased array antenna for an embodiment;

[0028] Figure 9 This is a schematic diagram of the overall model of a compactly arranged terahertz combined phased array antenna in an embodiment.

[0029] Figure label:

[0030] 1 is the antenna array structure, 2 is the substrate integrated coaxial line feed network, 3 is the transition connection network, 4 is the upper dielectric layer, 5 is the middle dielectric layer, 6 is the lower dielectric layer, 7 is the trapezoidal patch, 8 is the substrate integrated coaxial line feed port, 9 is the square ring metal patch, 10 is the first metallized via, 11 is the slot structure, 12 is the upper metal layer, 13 is the middle metal layer, 14 is the lower metal layer, 15 is the inner conductor of the first substrate integrated coaxial line, 16 is the slot structure, 17 is the second metallized via, 18 is the edge of the antenna element structure array, 19 is the substrate integrated coaxial line as a transmission line structure, 20 is the port of the second substrate integrated coaxial line, 21 is the matching stub, 22 is the coupling patch, and 23 is the rectangular waveguide. Detailed Implementation

[0031] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0032] like Figures 1-2 As shown, this embodiment provides a compact terahertz phased array antenna, including an antenna array structure 1, a substrate coaxial feed network 2, and a transition connection network 3; the antenna array structure is connected to the transition connection network 3 through the substrate coaxial feed network 2.

[0033] The antenna array structure comprises multiple antenna element structures arranged in m rows × n columns. For example... Figures 3-5As shown, each antenna element structure includes a first substrate integrated coaxial feed structure and an antenna body. The antenna body is stacked above the first substrate integrated coaxial feed structure. The antenna body includes an upper metal layer 12 and an upper dielectric layer 4 stacked on top of the upper metal layer 12. The upper dielectric layer 4 has multiple first metallized vias 10 penetrating the upper and lower surfaces along the circumferential direction, and its upper surface has a square annular metal sheet 9 and a radiating element. The square annular metal sheet 9 is located directly above the first metallized vias 10; the radiating element is located inside the square annular metal sheet 9 and includes two trapezoidal patches 7, which are arranged side by side in a mirror image with a gap between them. The upper metal layer 12 has a rectangular slot structure 11 corresponding to the gap between the two trapezoidal patches 7.

[0034] The first substrate integrated coaxial cable feed structure includes a lower metal layer 14, a lower dielectric layer 6, an intermediate metal layer 13, an intermediate dielectric layer 5, and an upper metal layer 12 stacked sequentially from bottom to top. The intermediate metal layer 13 serves as the internal feed layer of the substrate integrated coaxial cable, and has a slot-shaped structure 16 and a second metallized via 17 penetrating through it. The slot-shaped structure 16 is used to isolate the outer conductor and the inner conductor 15. The slot-shaped structure 16 is an open square annular slot, with a rectangular slot extending to one side edge of the intermediate metal layer connected to each end of its opening. The second metallized via 17 is disposed around the slot-shaped structure 16 and located outside the slot-shaped structure 16, with its top penetrating the intermediate dielectric layer 5 and its bottom penetrating the lower dielectric layer 6.

[0035] During implementation, the number of antenna elements in the antenna array structure is set according to requirements. This implementation uses a total of 16 antenna elements arranged in a 4×4 matrix. To achieve a compact structure, such as... Figures 6-7 As shown, the first substrate-integrated coaxial cable is used as the transmission structure 19 inside the antenna array. The cable connects the feed ports of the antenna elements inside the array to the edge 18 of the antenna element structure array, and then extends to the required locations at the transceiver front-end via a transition connection network. Figure 7 As shown, in the antenna array, some metallized vias can be reused as antenna coupling cavities and other unit feed transmission lines, effectively reducing the space required for array layout and further ensuring the compactness of the antenna array arrangement.

[0036] Furthermore, since high-frequency applications such as THz require microwave circuit substrate materials to have stable dielectric constants, low losses, and good chemical stability, the lower dielectric layer, middle dielectric layer, and upper dielectric layer described in this embodiment are all made of quartz dielectric substrates.

[0037] like Figure 8As shown, the transition connection network 3 consists of multiple transition structures. Each transition structure includes a second substrate integrated coaxial line and a rectangular waveguide 23. The second substrate integrated coaxial line is similar in structure to the first substrate integrated coaxial line, except that the inner conductor of the second substrate integrated coaxial line has a coupling patch 22 and a matching stub 21. The coupling patch 22 is located on the lower metal layer, and the matching stub 21 is located on the middle metal layer, with the matching stub 21 aligned vertically with the coupling patch 22. The rectangular waveguide 23 is coupled to the second substrate integrated coaxial line through the coupling patch 22. By loading the matching stub 21 and the coupling patch 22 in the multi-degree connection structure, good transmission characteristics are ensured. Since the second substrate integrated coaxial line used in the transition connection structure is similar in structure to the first substrate integrated coaxial line, it can be integrated with the antenna array and fabricated together, facilitating fabrication and assembly.

[0038] This embodiment also provides an extended structure for the above-mentioned compactly arranged terahertz phased array antenna, specifically as follows: Figure 9 As shown, the terahertz phased array antennas arranged in the above 4×4 matrix can be arranged in a mirror array to realize a compact arrangement of terahertz combined phased array antennas. That is, the mirror panel of the above 4×4 matrix terahertz phased array antennas can realize an 8×8 array.

[0039] In summary, the compactly arranged terahertz phased array antenna provided in this embodiment can cleverly realize an equivalent magnetoelectric dipole under the limitations of existing terahertz fabrication conditions, exhibiting wide-bandwidth beam characteristics. This overcomes the problems of narrow bandwidth in traditional patch antennas and the reduction in beamwidth caused by the bandwidth extension of traditional parasitic patches. By loading a square ring metal patch with grounding function onto the surface of the dielectric layer on the antenna, the isolation between elements in the array is effectively improved. The antenna array uses a first substrate integrated coaxial line as the transmission line structure to replace microstrip lines for feeding, effectively suppressing the problem of high-order modes and surface waves generated by microstrip line feeding severely affecting the stability and transmission rate of terahertz signals, thus achieving low-loss terahertz wave transmission.

[0040] In the transition connection network, matching stubs and coupling patches are loaded onto the inner conductor of the coaxial line integrated on the second substrate to adjust the coupling amount of the electric and magnetic fields, thereby achieving good matching. Furthermore, during fabrication, this transition structure and the first substrate-integrated coaxial line in the antenna array can be simultaneously processed on the same quartz substrate, exhibiting high integration.

[0041] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A compactly arranged terahertz phased array antenna, characterized in that: It includes an antenna array structure, a substrate coaxial feed network, and a transition connection network; the antenna array structure is connected to the transition connection network through the substrate coaxial feed network. The antenna array structure includes multiple arrays arranged in m rows. The antenna element structure is arranged in n columns, and each antenna element structure includes a first substrate integrated coaxial feed structure and an antenna body; wherein: The first substrate integrated coaxial cable feed structure includes a lower metal layer, a lower dielectric layer, an intermediate metal layer, an intermediate dielectric layer, and an upper metal layer stacked sequentially from bottom to top. The intermediate metal layer has a slot-shaped structure and a second metallized via through it. The slot-shaped structure is used to isolate the outer conductor and the inner conductor of the first substrate integrated coaxial cable feed structure. It is an open annular slot, with a rectangular slot extending to one side edge of the intermediate metal layer connected to each end of the opening. The second metallized via is arranged circumferentially along the slot-shaped structure and is located outside the slot-shaped structure. Its top penetrates the intermediate dielectric layer and its bottom penetrates the lower dielectric layer. The antenna body is stacked on top of the first substrate integrated coaxial feed structure, including an upper metal layer and an upper dielectric layer stacked on the upper metal layer; the upper dielectric layer has multiple first metallized vias penetrating the upper and lower surfaces along the circumferential direction, and an annular metal sheet and a radiating element are provided on its upper surface; the annular metal sheet is located directly above the first metallized vias; the radiating element is located inside the annular metal sheet and includes two trapezoidal patches, which are arranged side by side in a mirror image with a gap between them; the upper metal layer has a slot structure corresponding to the gap between the two trapezoidal patches; The transition connection network consists of multiple transition structures, each of which includes a second substrate integrated coaxial line and a rectangular waveguide. The second substrate integrated coaxial line is similar to the feeding structure of the first substrate integrated coaxial line, except that the inner conductor of the second substrate integrated coaxial line is provided with a coupling patch and a matching stub. The coupling patch is located on the lower metal layer, and the matching stub is located on the middle metal layer, with the matching stub aligned vertically with the coupling patch. The rectangular waveguide is coupled to the second substrate integrated coaxial line through the coupling patch.

2. The compactly arranged terahertz phased array antenna according to claim 1, characterized in that: The annular metal sheet is a square annular metal sheet; the open annular groove is an open square annular groove.

3. The compactly arranged terahertz phased array antenna according to claim 1, characterized in that: The slit structure is a rectangular slit structure.

4. A compactly arranged terahertz phased array antenna according to claim 1, characterized in that: The lower dielectric layer, the middle dielectric layer, and the upper dielectric layer are all quartz dielectric substrates.

5. A compactly arranged terahertz phased array antenna, comprising multiple pairs of compactly arranged terahertz phased array antennas as described in claim 1 arranged in a mirror array.

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