Terahertz broadband directional diagram reconfigurable slot antenna

Abstract

The invention discloses a terahertz broadband directional diagram reconfigurable slot antenna, belongs to the technical field of terahertz radio frequency front-end devices, and adopts a radiation unit and a four-direction symmetrical coplanar waveguide feed structure to realize dynamic beam reconstruction in combination with a composite beam ohmic contact type MEMS switch array. The technology is simplified through a single-layer quartz glass substrate, a multi-mode resonant cavity and a tunable artificial electromagnetic surface are integrated, the surface impedance is dynamically adjusted through an MEMS switch, the high-frequency dispersion effect is compensated, and the gain flatness is maintained. Through a three-mode beam reconstruction algorithm and control switch on-off combination,-40-degree, 0-degree and + 40-degree three-beam fast switching is achieved, the main lobe width covers 55.61-108.38 degrees, and the wide angular domain requirement is met. The technical contradiction of high gain, wide angular domain coverage and fast beam reconstruction of the terahertz antenna is effectively solved, and a high-performance and miniaturized solution is provided for 6G communication, intelligent radars and high-speed wireless transmission systems.

Description

Technical Field

[0001] The present invention relates to a terahertz broadband directional pattern reconfigurable slot antenna, belonging to the technical field of terahertz radio frequency front-end devices. Background Art

[0002] The rapid development of wireless communication technology, particularly the rise of terahertz (THz) technology, has placed higher demands on the performance of antenna systems. Terahertz waves, with frequencies ranging from 0.1 to 10 THz, lie between microwaves and infrared radiation. They possess extremely large channel bandwidth and extremely high data rates, making them considered a key technology for future applications such as 6G communications, high-speed wireless data transmission, THz imaging, and intelligent radar systems. However, to fully realize the potential of THz technology, antenna systems must overcome a number of technical challenges.

[0003] Traditional antenna systems face many limitations in terms of design, manufacturing, and application. First, traditional antenna design is highly dependent on regular geometric shapes and sizes. For the design of complex or irregular shapes, there is a lack of effective mathematical tools and optimization methods, resulting in low design efficiency and difficulty in achieving optimal performance. Secondly, in the traditional antenna manufacturing process, high-precision processing requirements often lead to high costs and complex processes. Especially when the antenna size is miniaturized or the structure is complex, the manufacturing difficulty increases significantly. In addition, traditional antenna systems are sensitive to environmental changes, such as temperature, humidity, mechanical vibration, etc., which may cause a significant decline in antenna performance or even failure. At the application level, traditional antenna systems have difficulty in achieving dynamic and flexible beam pointing control and cannot meet the communication needs of high-speed mobile platforms or complex electromagnetic environments.

[0004] While terahertz antenna technology holds enormous potential, it also faces unique challenges. The short wavelength of terahertz waves allows for significant reductions in antenna size, facilitating the miniaturization and integration of antenna systems. However, the high propagation losses of terahertz waves place higher demands on the efficiency and directivity of antenna systems. Furthermore, beam pointing control in the terahertz frequency band is more complex, requiring higher-precision phase and amplitude control for precise beam pointing and scanning.

[0005] To overcome these challenges, researchers have proposed various beamforming technologies, such as beamforming, which uses multiple sensors to receive signals and generates directional beams through weighted summation, thereby enhancing the reception or transmission of signals in a specific direction. However, traditional beamforming technologies still face many limitations in practical applications, such as high computational complexity, poor real-time performance, and demanding hardware requirements.

[0006] Against this backdrop, this paper proposes a precision antenna assembly design based on a composite beam RF MEMS switch array and a broadband impedance matching network. Through innovative antenna structure and advanced manufacturing processes, this design aims to address many challenges facing both traditional antenna systems and terahertz antenna technology. Summary of the Invention

[0007] The present invention aims to overcome the shortcomings of the aforementioned background technologies and provide a terahertz broadband reconfigurable slot antenna. This invention utilizes a symmetrical layout and multi-branch structure, as well as a horizontal arrangement and independent connection structure, to achieve efficient radiation and flexible control of the antenna system. Furthermore, the embedded square structure, composite beam RF MEMS switches, and precision testing structures further optimize the antenna's radiation characteristics and test accuracy.

[0008] The object of the present invention is achieved like this:

[0009] A terahertz pattern reconfigurable slot antenna comprises a radiating patch 1, a dielectric substrate 8, and a metal ground backplane 9, wherein the radiating patch and the metal ground backplane are respectively located on the upper and lower surfaces of the dielectric substrate; a coplanar waveguide 2, a transmission line 3, and a composite beam ohmic contact MEMS switch 4;

[0010] There are four coplanar waveguides, all located on the upper surface of the dielectric substrate, with two coplanar waveguides facing each other to form two coplanar waveguide groups; the four coplanar waveguides are arrayed around the periphery of the radiating patch and form an annular defect region between the four coplanar waveguides and the radiating patch; the two coplanar waveguides in coplanar waveguide group a are connected to the radiating patch via two fracture branches;

[0011] The transmission line 3 is located in a rectangular defect region of a coplanar waveguide in the coplanar waveguide group b; the annular defect region and the rectangular defect region are connected, wherein there is no contact between the transmission line and the radiation patch;

[0012] The composite beam ohmic contact MEMS switch 4 is located in the annular defect area and is used to realize the disconnection and connection of the fracture branches.

[0013] Furthermore, four composite beam ohmic contact MEMS switches 4 are provided, and the four composite beam ohmic contact MEMS switches correspond to the four fracture branches one by one.

[0014] Furthermore, the composite beam ohmic contact MEMS switch 4 includes an upper beam structure, a bridge pier and a pull-down electrode; wherein the upper beam structure is arc-shaped and has two branches, forming an F shape.

[0015] The upper beam structure includes a silica beam, a switch beam and an action beam, and the switch beam and the pull-down electrode are both located in the annular defect area, wherein the switch beam is located directly above the fracture branch and directly opposite the fracture of the fracture branch. When the switch beam is pulled down, the fracture branch is connected; the bridge pier is located on the upper surface of the coplanar waveguide, the action beam extends from the top of the bridge pier to the switch beam and is connected to the switch bridge through the silica beam, and the pull-down electrode is located directly below the action beam.

[0016] Furthermore, each composite beam ohmic contact MEMS switch 4 is provided with an action beam and a switch beam, and both the switch beam and the action beam are covered on the lower surface of the silicon dioxide beam, and the upper surface of the pull-down electrode is provided with a silicon nitride insulating layer; the pull-down electrode is connected to the corresponding DC patch pad A through a DC bias line;

[0017] There are four DC patch pads in total and they correspond one to one to the four action beams.

[0018] Furthermore, adjacent coplanar waveguides have gaps between them for the DC bias line to pass through, and the adjacent coplanar waveguides are connected by isolation bridges; the isolation bridges have no contact with the DC bias line.

[0019] Furthermore, the two branch ends of the upper beam of each composite beam ohmic contact MEMS switch 4 are respectively placed on two bridge piers, and the two bridge piers are respectively located on the upper surfaces of two adjacent coplanar waveguides; the coplanar waveguides are connected to the DC patch pad B.

[0020] Furthermore, the edges of the annular defect area and the rectangular defect area are transitioned by bevel cutting and chamfering; the transmission line is a T-shaped patch, part of which is located in the annular defect area and part of which is located in the rectangular defect area.

[0021] Furthermore, the action beam and the silica beam are both provided with through holes.

[0022] Furthermore, the switch beam and the action beam are both metal beams, and two contacts are provided on the lower surface of the switch beam, and the two contacts correspond to the two sides of the fracture of the fracture branch respectively.

[0023] Furthermore, the dielectric substrate 8 is made of quartz glass with a dielectric constant of 3.78 and a loss tangent of 0.0008, and serves as a supporting base for the antenna components.

[0024] Compared with the background technology, the present invention has the following advantages:

[0025] 1. The present invention adopts a radiation unit as the core, symmetrically extending four fracture branches, and providing a composite beam ohmic contact MEMS switch connected to the outside on the fracture branches, which is conducive to achieving multi-directional radiation and flexible control of the beam.

[0026] 2. Composite Beam RF MEMS Switch and Precision Test Structure: This invention utilizes a composite beam ohmic contact MEMS switch, combined with an isolation bridge, DC bias line, and DC patch pads, to dynamically reconstruct and precisely test the antenna radiation pattern. Furthermore, the silicon nitride insulating layer, beam vias, and silicon dioxide beam structure ensure the switch's stability and reliability.

[0027] 3. This invention utilizes a multimode resonant cavity, optimizes the geometric topology of radiating patches, integrates a tunable artificial electromagnetic surface, and dynamically adjusts the surface impedance through a MEMS switch to compensate for high-frequency dispersion and maintain gain flatness. A composite beam RF MEMS switch, employing a silicon dioxide / metal composite cantilever beam structure and a 30V on-state DC bias voltage, has been developed, overcoming the performance bottleneck of traditional switches in the terahertz frequency range.

[0028] 4. The core advantage of the present invention is that it simplifies the feeding and beam reconstruction mechanism, and proposes a single-layer quartz glass substrate coplanar waveguide feeding structure to replace the traditional multi-layer board solution. The dielectric thickness is only 0.1mm, and the processing error tolerance is improved to ±5μm, which significantly reduces the process complexity. Through the three-mode beam reconstruction algorithm, the switch array on-off combination is controlled to achieve -40°, 0°, and +40° three-beam pointing switching. The beam scanning speed is less than 10μs, which meets the needs of high-speed dynamic scenarios. It has three radiation modes, and the main lobe widths in the three modes are 108.38°, 56.4°, and 94.04° respectively, supporting wide-angle coverage. It is small in size and easy to integrate. The antenna unit size is only 0.5mm×0.5mm×0.1mm. It can be directly bonded to the terahertz chip and is suitable for large-scale array integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a top view of the overall structure of the terahertz broadband directional pattern reconfigurable slot antenna

[0030] Figure 2 Side view of the dielectric substrate and metal backplane of the terahertz broadband reconfigurable slot antenna

[0031] Figure 3 This is a side view of the MEMS switch structure.

[0032] Figure 4 This is a top view of the MEMS switch structure.

[0033] Figure 5 This is the S11 curve of the antenna impedance matching

[0034] Figure 6 The gain pattern of the antenna in three modes

[0035] In the figure: 1. Radiating patch (radiating unit), 2. Coplanar waveguide, 3. Transmission line, 4. Composite beam ohmic contact MEMS switch, 5. Isolation bridge, 6. DC bias line, 7. DC patch pad, 8. Dielectric substrate, 9. Metal ground backplane, 12. Through hole on beam, 14. Bridge pier, 15. Silicon dioxide beam, 16. Action beam, 17. Pull-down electrode, 18. Switch beam, 1-2, Fracture branches. DETAILED DESCRIPTION

[0036] The present invention will be described in further detail below.

[0037] A terahertz pattern reconfigurable slot antenna comprises a radiating patch 1, a dielectric substrate 8, and a metal ground backplane 9, wherein the radiating patch and the metal ground backplane are respectively located on the upper and lower surfaces of the dielectric substrate; a coplanar waveguide 2, a transmission line 3, and a composite beam ohmic contact MEMS switch 4;

[0038] There are four coplanar waveguides, all located on the upper surface of the dielectric substrate, with two coplanar waveguides facing each other to form two coplanar waveguide groups; the four coplanar waveguides are arrayed around the periphery of the radiating patch and form an annular defect region between the four coplanar waveguides and the radiating patch; the two coplanar waveguides in coplanar waveguide group a are connected to the radiating patch via two fracture branches;

[0039] The transmission line 3 is located in a rectangular defect region of a coplanar waveguide in the coplanar waveguide group b; the annular defect region and the rectangular defect region are connected, wherein there is no contact between the transmission line and the radiation patch;

[0040] The composite beam ohmic contact MEMS switch 4 is located in the annular defect area and is used to realize the disconnection and connection of the fracture branches.

[0041] Furthermore, four composite beam ohmic contact MEMS switches 4 are provided, and the four composite beam ohmic contact MEMS switches correspond to the four fracture branches one by one.

[0042] Furthermore, the composite beam ohmic contact MEMS switch 4 includes an upper beam structure, a bridge pier and a pull-down electrode; wherein the upper beam structure is arc-shaped and has two branches, forming an F shape.

[0043] The upper beam structure includes a silica beam, a switch beam and an action beam, and the switch beam and the pull-down electrode are both located in the annular defect area, wherein the switch beam is located directly above the fracture branch and directly opposite the fracture of the fracture branch. When the switch beam is pulled down, the fracture branch is connected; the bridge pier is located on the upper surface of the coplanar waveguide, the action beam extends from the top of the bridge pier to the switch beam and is connected to the switch bridge through the silica beam, and the pull-down electrode is located directly below the action beam.

[0044] Furthermore, each composite beam ohmic contact MEMS switch 4 is provided with an action beam and a switch beam, and both the switch beam and the action beam are covered on the lower surface of the silicon dioxide beam, and the upper surface of the pull-down electrode is provided with a silicon nitride insulating layer; the pull-down electrode is connected to the corresponding DC patch pad A through a DC bias line;

[0045] There are four DC patch pads in total and they correspond one to one to the four action beams.

[0046] Furthermore, adjacent coplanar waveguides have gaps between them for the DC bias line to pass through, and the adjacent coplanar waveguides are connected by isolation bridges; the isolation bridges have no contact with the DC bias line.

[0047] Furthermore, the two branch ends of the upper beam of each composite beam ohmic contact MEMS switch 4 are respectively placed on two bridge piers, and the two bridge piers are respectively located on the upper surfaces of two adjacent coplanar waveguides; the coplanar waveguides are connected to the DC patch pad B.

[0048] Furthermore, the edges of the annular defect area and the rectangular defect area are transitioned by bevel cutting and chamfering; the transmission line is a T-shaped patch, part of which is located in the annular defect area and part of which is located in the rectangular defect area.

[0049] Furthermore, the action beam and the silica beam are both provided with through holes.

[0050] Furthermore, the switch beam and the action beam are both metal beams, and two contacts are provided on the lower surface of the switch beam, and the two contacts correspond to the two sides of the fracture of the fracture branch respectively.

[0051] Here is a more specific description:

[0052] Reference Figure 1 In this embodiment, the radiating patch of the radiating unit adopts a circular structure design. As the core radiating component of the antenna system, it directly participates in the transmission and reception of electromagnetic waves. Its design takes into account the characteristics of the terahertz frequency band to achieve efficient electromagnetic wave radiation.

[0053] The coplanar waveguide 2, the antenna's primary feed structure, features a tapered gap and chamfered corners for excellent impedance matching with the transmission line. Transmission line 3 efficiently transmits electromagnetic signals to and from the radiating element.

[0054] The composite beam ohmic contact MEMS switch 4 achieves dynamic reconfiguration of the antenna's radiation pattern by precisely controlling the switch state. The switch utilizes a clamped-beam composite material design to ensure structural strength and stability. During the manufacturing process, the switch's dimensions and position must be strictly controlled to ensure optimal performance.

[0055] Isolation bridges 5, DC bias lines 6, and DC patch pads 7 are placed at the antenna edge or in specific locations to facilitate precise testing and integration in the terahertz band using probes. The isolation bridges connect the DC bias lines, which transmit test signals, to the DC patch pads, which connect to test equipment.

[0056] The dielectric substrate 8 is made of quartz glass with a dielectric constant of 3.78 and a loss tangent of 0.0008, serving as a supporting base for the antenna components.

[0057] The metal back plate 9 is printed on the lower surface of the dielectric substrate and is used to reflect electromagnetic waves and improve the forward gain of the antenna.

[0058] The specific structure of the composite beam ohmic contact MEMS switch in this embodiment is as follows: Figure 3 and Figure 4 ,In this embodiment, the composite beam ohmic contact MEMS switch ,is provided with four corresponding four fracture branches.

[0059] Composite beam ohmic contact MEMS switches include:

[0060] The bridge pier is used to support and fix the MEMS switch to ensure the stability and reliability of the switch.

[0061] The silicon nitride insulating layer provides electrical isolation, preventing short circuits between different circuit layers.

[0062] As part of the MEMS switch, the action beam realizes the on and off of the switch through bending deformation.

[0063] Contacts and switch beams are used to achieve electrical connections and ensure reliable signal transmission. The silicon dioxide beam, as the cantilever beam structure of the MEMS switch, is made of silicon dioxide material and has good mechanical properties and stability.

[0064] The composite beam ohmic contact MEMS switch includes an upper beam structure, a bridge pier and an electrode; wherein the upper beam structure spans the fracture branch;

[0065] The upper beam structure includes a silica beam, a switch beam and an action beam, wherein the switch beam and the action beam are both made of metal; the switch beam is connected to the silica beam and the action beam, and there is no electrical contact between the switch beam and the action beam, while the action beam and the bridge pier have electrical contact; when the action beam moves, it drives the switch beam to move in the same direction; the silica beam is located on the upper surface of the switch and action beams.

[0066] Among them, the switch beam is located just above the fracture of the fracture branch; a pull-down electrode is provided under each action beam, and a silicon nitride electrode insulating layer is provided on the upper surface of the electrode.

[0067] The contact is arranged on the lower surface of the switch beam. When the composite beam ohmic contact type MEMS switch is in an on state, the contact abuts against both sides of the fracture of the corresponding fracture branch.

[0068] This embodiment simplifies the process through a single-layer quartz glass substrate, integrates a multi-mode resonant cavity and a tunable artificial electromagnetic surface, and uses a MEMS switch to dynamically adjust the surface impedance, compensate for high-frequency dispersion effects, and maintain gain flatness. Through a three-mode beam reconstruction algorithm, the switch on-off combination is controlled to achieve fast switching of three beams of -40°, 0°, and +40°. The main lobe width covers 55.61° to 108.38°, meeting the needs of a wide angle domain. A silicon dioxide / metal composite cantilever beam MEMS switch is used, combined with a test line bridge and a pad, to support precise testing in the terahertz band. The antenna unit size is only 0.5mm 3 The return loss is less than -10dB at the center frequency of 340GHz, which supports direct bonding to terahertz chips and is suitable for large-scale array integration.

[0069] Figure 1 —4 The dimensions of the structure are (in micrometers):

[0070] Structure a length = 190, structure b length = structure e length = 500, structure c length = 130, structure d length = 225, structure f length = 24, structure g length = 20, structure h length = 60, structure i length = 4, structure j length = 10, structure k length = 30, structure l length = 70

[0071] Attachment Figure 5 Shown is the antenna return loss curve, the antenna center frequency is 340GHz, in all three modes at the center frequency is less than -10Db.

[0072] In this embodiment, the antenna includes three beam modes, referring to Figure 1 , four composite beam MEMS switches, upper left, upper right, lower left, lower right,

[0073] Mode 1: The upper left, upper right, lower left, and lower right of the composite beam MEMS switch are all disconnected.

[0074] Mode 2: Composite beam MEMS switch upper left, upper right conduction, lower left, lower right, disconnection,

[0075] Mode 3 composite beam MEMS switch is on at the lower right, and disconnected at the upper left, lower left, and upper right.

[0076] Attachment Figure 6The display shows the gain pattern of the antenna in three modes. The control switch array on-off combination realizes the switching of three beam directions of -40°, 0° and +40° in mode 1, mode 2 and mode 3 respectively. The main lobe widths in the three modes are 55.61°, 58.94° and 98.56° respectively, supporting wide-angle coverage.

[0077] The above is only an example. If one wants to obtain a terahertz broadband directional pattern reconfigurable slot antenna at different center frequencies, different parameters can be adjusted according to the specific implementation method to achieve different operating frequency bands and guiding effects.

[0078] It should be understood that the above description of the specific implementation methods of this patent is merely an exemplary description listed to facilitate ordinary technicians in this field to understand the patent solution, and does not imply that the scope of protection of this patent is limited to these individual examples. Ordinary technicians in this field can fully understand the technical solution of this patent and, without any creative work, obtain more specific implementation methods by combining technical features, replacing some technical features, adding more technical features, etc. to the examples listed in this patent. All these specific implementation methods are within the scope of the claims of this patent. Therefore, these new specific implementation methods should also be within the scope of protection of this patent.

Claims

1. A terahertz broadband directional pattern reconfigurable slot antenna, comprising a radiating patch (1), a dielectric substrate (8) and a metal ground backplane (9), wherein the radiating patch and the metal ground backplane are respectively located on the upper surface and the lower surface of the dielectric substrate; characterized in that: It includes a coplanar waveguide (2), a transmission line (3) and a composite beam ohmic contact type MEMS switch (4); There are four coplanar waveguides, all located on the upper surface of the dielectric substrate, with two coplanar waveguides facing each other to form two coplanar waveguide groups; the four coplanar waveguides are arrayed around the periphery of the radiating patch and form an annular defect region between the four coplanar waveguides and the radiating patch; the two coplanar waveguides in coplanar waveguide group a are connected to the radiating patch via two fracture branches; The transmission line (3) is located in a rectangular defect region of a coplanar waveguide in the coplanar waveguide group b; the annular defect region and the rectangular defect region are connected, wherein there is no contact between the transmission line and the radiation patch; The composite beam ohmic contact type MEMS switch (4) is located in the annular defect area and is used to realize the disconnection and connection of the fracture branches.

2. The terahertz broadband pattern reconfigurable slot antenna according to claim 1, characterized in that: The composite beam ohmic contact type MEMS switches (4) are provided with four, and the four composite beam ohmic contact type MEMS switches correspond to the four fracture branches one by one.

3. The terahertz pattern reconfigurable slot antenna according to claim 1, wherein: The composite beam ohmic contact type MEMS switch (4) comprises an upper beam structure, a bridge pier and a pull-down electrode; wherein the upper beam structure is arc-shaped and has two branches, forming an F shape. The upper beam structure includes a silica beam, a switch beam and an action beam, and the switch beam and the pull-down electrode are both located in the annular defect area, wherein the switch beam is located directly above the fracture branch and directly opposite the fracture of the fracture branch. When the switch beam is pulled down, the fracture branch is connected; the bridge pier is located on the upper surface of the coplanar waveguide, the action beam extends from the top of the bridge pier to the switch beam and is connected to the switch bridge through the silica beam, and the pull-down electrode is located directly below the action beam.

4. The terahertz broadband reconfigurable pattern slot antenna according to claim 3, characterized in that: Each composite beam ohmic contact type MEMS switch (4) is provided with an action beam and a switch beam, both of which are covered on the lower surface of the silicon dioxide beam, and the upper surface of the pull-down electrode is provided with a silicon nitride insulating layer; the pull-down electrode is connected to the corresponding DC patch pad A through a DC bias line; There are four DC patch pads in total and they correspond one to one to the four action beams.

5. The terahertz broadband pattern reconfigurable slot antenna according to claim 4, characterized in that: There are gaps between adjacent coplanar waveguides for the DC bias line to pass through, and the adjacent coplanar waveguides are connected by isolation bridges; the isolation bridges have no contact with the DC bias line.

6. The terahertz broadband directional pattern reconfigurable slot antenna according to claim 3, characterized in that: The two branch ends of the upper beam of each composite beam ohmic contact type MEMS switch (4) are respectively placed on two bridge piers, and the two bridge piers are respectively located on the upper surfaces of two adjacent coplanar waveguides; the coplanar waveguides are connected to the DC patch pad B.

7. The terahertz broadband pattern reconfigurable slot antenna according to claim 1, characterized in that: The edges of the annular defect area and the rectangular defect area are transitioned by bevel cutting and chamfering; the transmission line is a T-shaped patch, part of which is located in the annular defect area and part of which is located in the rectangular defect area.

8. The terahertz broadband pattern reconfigurable slot antenna according to claim 3, characterized in that: The action beam and the silicon dioxide beam are both provided with beam through holes.

9. The terahertz broadband pattern reconfigurable slot antenna according to claim 3, characterized in that: The switch beam and the action beam are both metal beams. Two contacts are provided on the lower surface of the switch beam, and the two contacts correspond to the two sides of the fracture of the fracture branch respectively.

10. The terahertz broadband pattern reconfigurable slot antenna according to claim 1, characterized in that: The dielectric substrate (8) uses quartz glass with a dielectric constant of 3.78 and a loss tangent of 0.0008, and serves as a supporting base for various antenna components.

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