A reconfigurable antenna based on RF-MEMS switch terahertz pattern

Abstract

The application discloses a kind of based on RF-MEMS switch terahertz directional diagram reconfigurable antenna, belong to terahertz radio frequency front-end device technical field.The antenna is by radiating element, composite beam ohmic contact MEMS switch, coplanar waveguide feed structure, microstrip transmission line, dielectric substrate and metal ground back plate composition.The antenna adopts single layer quartz glass substrate integrated waveguide (SIW) feed structure, realizes and microstrip transmission line excellent impedance matching, relative bandwidth is more than 19%, through DC bias driving MEMS switch action.The antenna has relatively wide impedance bandwidth.Using the on-off control directional diagram reconfigurable realization of switch, antenna in 00, 01, 10 mode, realize-40°, 0°, +40° three beam pointing switch, three modes are respectively 55.61°, 58.94°, 98.56°, support wide angle domain coverage.

Description

Technical Field

[0001] This invention relates to a terahertz broadband pattern reconfigurable antenna, belonging to the field of terahertz radio frequency front-end device technology. Background Technology

[0002] Reconfigurable pattern antennas are a key technology for achieving efficient electromagnetic wave manipulation in the terahertz band. Traditional antenna systems rely on phased arrays or multi-beam networks for beam scanning, but these suffer from high hardware complexity, high power consumption, and high cost. Reconfigurable pattern antennas reconfigure the radiation structure or feed path by integrating radio frequency switching devices, achieving multi-mode radiation characteristic switching with a single antenna element. They offer advantages such as low profile, low power consumption, and fast response, making them particularly suitable for the stringent requirements of integration and lightweight design in the terahertz band.

[0003] Current terahertz pattern reconfigurable antenna technology faces the following bottlenecks:

[0004] Existing designs primarily focus on frequencies below 10 GHz or millimeter-wave satellite communication bands. The terahertz band (0.1-10 THz) suffers from significant high-frequency effects, leading to enhanced coupling between radiating patches and a dramatic increase in dielectric loss, resulting in an exponential increase in the difficulty of broadband design and making it difficult to meet the bandwidth requirements of ultra-high-speed communication. Traditional PIN diodes exhibit prominent parasitic parameters above 300 GHz, with insertion losses exceeding 3 dB, severely degrading antenna efficiency. Varactor diodes have limited tuning ranges, making it difficult to balance broadband matching and linearity requirements. Achieving broadband impedance matching necessitates the use of multi-layer stacked transmission lines or artificial electromagnetic materials; however, the high precision requirements of micro / nano fabrication in the terahertz band result in high manufacturing costs, and multi-layer structures easily introduce parasitic radiation modes, limiting bandwidth expansion. Most reconfigurable antennas only support discrete angle switching, and their gain drops sharply with frequency shift, making it difficult to meet the dynamic multipath suppression or wide-angle detection requirements of terahertz communication. Summary of the Invention

[0005] To address the aforementioned issues, this invention proposes a terahertz pattern reconfigurable antenna based on a composite beam RF MEMS switch array and a broadband impedance matching network. Employing novel RF MEMS switching and broadband impedance matching technology, beam pointing switching and ultra-wideband spectrum coverage are achieved through dynamic reconfiguration of the radiating patch operating modes. This antenna is primarily applied to 6G communication, terahertz imaging, high-speed wireless data transmission, and intelligent radar systems.

[0006] The objective of this invention is achieved as follows:

[0007] A terahertz pattern reconfigurable antenna based on an RF-MEMS switch includes a dielectric substrate 15 and a metal ground backplate 16, wherein the metal ground backplate 16 is located on the lower surface of the substrate; the upper surface of the dielectric substrate is provided with a composite beam ohmic contact MEMS switch 2, a coplanar waveguide 4, a microstrip transmission line 5, a parasitic patch 3, and a radiating patch 1.

[0008] The radiating patch 1 is located on one side of the coplanar waveguide 4; the coplanar waveguide 4 has a gradient slot on the side near the radiating patch, and the gradient slot extends toward the side away from the radiating patch; the microstrip transmission line 5 is in the form of a straight line, with one end connected to the radiating patch and the other end located at the bottom edge of the gradient slot, without contacting the bottom edge.

[0009] There are two parasitic patches 3, located on both sides of the radiating patch 1, and both are parallel to the microstrip transmission line 5; each parasitic patch is a segmented strip patch, and adjacent segmented patches are connected by a composite beam ohmic contact MEMS switch 2.

[0010] Furthermore, the inner edges of the gradient gap are stepped, and the distance between the inner edges gradually decreases from the opening to the bottom edge.

[0011] Furthermore, the parasitic patch and the radiating patch are located on the same side of the coplanar waveguide.

[0012] Furthermore, the dielectric substrate 15 is made of quartz glass with a dielectric constant of 3.78 and a loss tangent of 0.0008.

[0013] Furthermore, a rectangular groove is provided on the side of the radiating patch near the coplanar waveguide; the rectangular groove is directly opposite the gradient slot, and one end of the microstrip transmission line 5 extends into the rectangular groove and connects to the radiating patch.

[0014] Furthermore, the width of adjacent ends of the segmented patch gradually narrows.

[0015] Furthermore, the composite beam ohmic contact MEMS switch 2 includes an upper beam structure, piers, and electrodes; wherein the upper beam structure spans the strip patch, and the two ends of the upper beam structure are respectively connected to the piers on both sides of the strip patch;

[0016] The upper beam structure includes a silica beam, a switch beam, and an actuating beam, wherein the switch beam and the actuating beam are both metal; the switch beam is connected to the silica beam and the actuating beam, and there is no electrical contact between the switch beam and the actuating beam, while the actuating beam and the bridge pier have electrical contact; when the actuating beam moves, it drives the switch beam to move in the same direction.

[0017] There is a break between two adjacent segment patches; the switch beam is located directly above the break.

[0018] Each moving beam has an electrode underneath, and the upper surface of the electrode has a silicon nitride electrode insulating layer.

[0019] Furthermore, it also includes contacts; the contacts are located on the lower surface of the switch beam, and when the composite beam ohmic contact MEMS switch is in the on state, the contacts abut against the top of the corresponding segmented patch.

[0020] Furthermore, it also includes surface mount pads; each strip-shaped patch corresponds to two surface mount pads; one surface mount pad is connected to the pier, and the other surface mount pad is connected to the electrode.

[0021] Furthermore, the action beam is provided with through holes.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1. In this invention, a multimode resonant cavity and a gradually increasing gap coupling feeding technology are employed. By optimizing the geometric topology of the radiating patch, an instantaneous bandwidth coverage of over 60 GHz is achieved within the 300-400 GHz frequency band, with a relative bandwidth exceeding 15%. An integrated tunable artificial electromagnetic surface is used, and the surface impedance is dynamically adjusted via a MEMS switch to compensate for high-frequency dispersion effects and maintain gain flatness.

[0024] We developed a composite beam RF MEMS switch, which adopts a silicon dioxide / metal composite cantilever beam structure and has a DC bias voltage of 30V, breaking through the performance bottleneck of traditional switches in the terahertz frequency band.

[0025] 2. The core advantage of this invention lies in simplifying the feeding and beam reconstruction mechanisms. It proposes a single-layer quartz glass substrate coplanar waveguide feeding structure to replace the traditional multilayer board solution. The dielectric thickness is only 0.1mm, and the processing error tolerance is increased to ±5μm, significantly reducing process complexity. Through a three-mode beam reconstruction algorithm, the switching array is controlled to achieve -40°, 0°, and +40° beam pointing switching, with a beam scanning speed of less than 10μs, meeting the requirements of high-speed dynamic scenarios. It has three radiation modes with main lobe widths of 55.61°, 58.94°, and 98.56° respectively, supporting wide-angle coverage. Its small size facilitates integration; the antenna element size is only 5mm × 10mm × 0.1mm, allowing direct bonding with terahertz chips and making it suitable for large-scale array integration. Attached Figure Description

[0026] Figure 1 This is a top view of the overall structure of a terahertz broadband pattern reconfigurable antenna.

[0027] Figure 2 This is a top view of a MEMS switch structure.

[0028] Figure 3 This is a side view of a MEMS switch structure.

[0029] Figure 4 This is a side view of the overall structure of a terahertz broadband pattern reconfigurable antenna.

[0030] Figure 5 This is the impedance matching S11 curve of the antenna.

[0031] Figure 6 These are the antenna gain patterns in three modes.

[0032] In the figure: 1. Radiation patch, 2. Composite beam ohmic contact MEMS switch, 3. Parasitic patch, 4. Coplanar waveguide, 5. Microstrip transmission line, 6. Silicon dioxide beam, 7. Through hole on beam, 8. Electrode, 9. Switch beam, 10. Contact, 11. Silicon nitride insulating layer, 12. Actuating beam, 13. Pier, 15. Dielectric substrate, 16. Metal ground backplate. Detailed Implementation

[0033] The present invention will now be described in further detail.

[0034] The following is in conjunction with the appendix Figures 1-6 The embodiments and examples will further illustrate specific implementations of the present invention in detail.

[0035] With attachment Figure 1 , 4 Taking the antenna structure as an example,

[0036] This embodiment includes a radiating patch 1, a composite beam ohmic contact MEMS switch, a coplanar waveguide 4, a microstrip transmission line 5, a dielectric substrate 15, a metal ground backplane 16, and a patch pad 23.

[0037] Among them, the radiating patch 1, as the core radiating component of the antenna system, directly participates in the transmission and reception of electromagnetic waves. A rectangular slot is provided on one side of the radiating patch to adjust the impedance matching of the antenna, optimize the resonant point offset, and broaden the impedance bandwidth. By optimizing the size of the rectangular defect, precise control of the resonant point can be achieved.

[0038] Composite beam ohmic contact MEMS switch: Enables dynamic reconstruction of the antenna radiation pattern through precise control of the switch state. Utilizing a fixed-beam composite material design, composed of metal and silica beam layers, it ensures structural strength and stability.

[0039] Coplanar waveguide: As the main feed structure for the antenna, it employs a tapered gap design to achieve excellent impedance matching with the microstrip transmission line.

[0040] Microstrip transmission line on coplanar waveguide: Connected to the coplanar waveguide, it is responsible for efficiently transmitting electromagnetic signals to the radiating patch.

[0041] Dielectric substrate: Quartz glass with a dielectric constant of 3.78 and a loss tangent of 0.0008 is used as the supporting substrate for each component of the antenna.

[0042] Metal ground plane: Printed on the lower surface of the dielectric substrate, it reflects electromagnetic waves, suppresses backlobe radiation, and improves the forward gain of the antenna. Microstrip transmission lines are connected to coplanar waveguides to ensure efficient signal transmission.

[0043] Parasitic patches: Printed on both sides of the radiating patch, based on the on / off state of the composite beam MEMS switch, change the current flow and adjust the beam direction.

[0044] The composite beam ohmic contact MEMS switch in this embodiment has the following specific structure. Figure 2 and Figure 3 In this embodiment, two parasitic patches are provided, each divided into three segments, forming three segmented patches located on the same straight line. Four composite beam ohmic contact MEMS switches are provided, two of which correspond to one parasitic patch, used to connect two adjacent segmented patches to achieve on / off switching between adjacent segmented patches.

[0045] The composite beam ohmic contact MEMS switch includes an upper beam structure, piers, and electrodes; the upper beam structure spans a strip patch, and the two ends of the upper beam structure are respectively connected to the piers on both sides of the strip patch;

[0046] The upper beam structure includes a silica beam, a switch beam, and an actuating beam, wherein the switch beam and the actuating beam are both metal; the switch beam is connected to the silica beam and the actuating beam, and there is no electrical contact between the switch beam and the actuating beam, while the actuating beam and the pier have electrical contact; when the actuating 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 the actuating beam.

[0047] There is a break between two adjacent segment patches; the switch beam is located directly above the break; an electrode is provided below each actuating beam, and a silicon nitride electrode insulating layer is provided on the upper surface of the electrode.

[0048] The contacts are located on the lower surface of the switch beam. When the composite beam ohmic contact MEMS switch is in the ON state, the contacts abut against the top of the corresponding segment patch.

[0049] The surface-mount pads are located at the edge of the antenna, facilitating precise testing and integration in the terahertz band via RF probes fed through the coplanar waveguide notch. The DC test interface surface-mount pads work in conjunction with the RF probes to achieve precise testing in the terahertz band.

[0050] Here, we will select one size combination for example illustration (the data below is in micrometers).

[0051] Figure 1 ,4 The dimensions of the structure are:

[0052] The structure lengths are: e = 400, f = 400.5, d = 1000, a = 250, b = 100, c = 80, g = 610, and o = 1200.

[0053] With attachment Figure 2 , 3 Taking MEMS switch structures as an example,

[0054] The bridge piers serve as the fixed support structure for the switch, ensuring its stability during operation. Through holes in the beams optimize stress distribution in the silicon dioxide beams and the actuating beam, improving switch reliability. A silicon nitride insulating layer isolates the actuating beam from the switch beam, preventing short circuits and ensuring normal switch operation. When the switch is on, the contacts achieve reliable contact between the segmented pads and the switch beam. The composite structure of the silicon dioxide beam and the switch beam enhances the switch's structural strength. The actuating beam, as the switch's operating component, deforms under the influence of an electric field, enabling the switch to turn on and off.

[0055] The actuation mechanism involves applying voltage via a DC bias line. When the voltage reaches the driving voltage value, the electrostatic force generated by the electrodes attracts the actuating beam, causing it to bend downwards. As the voltage increases further to the pull-in voltage, the deformation reaches its maximum value, the contacts make contact with the segmented pads, and the switch is turned on. Reducing the voltage below the threshold decreases the electrostatic force, causing the actuating beam to spring back, the contacts to detach from the parasitic pads, and the switch is turned off.

[0056] Here, we will select one size combination for example illustration (the data below is in micrometers).

[0057] Figure 2 , 3 The dimensions of the structure are:

[0058] Structure h = 60, structure i = 40, structure j = 15, structure k = 55, structure l = 4, structure m = 30, structure n = 50.

[0059] Appendix Figure 5 The diagram shows the antenna return loss curve. The antenna has a center frequency of 340 GHz. In the frequency range of 373.85 GHz to 307.86 GHz, S11 is significantly less than -10 dB, and it has a bandwidth of 65.99 GHz, with a relative bandwidth of 19.4%. The antenna has a wide impedance bandwidth.

[0060] In this embodiment, the antenna includes three beam patterns, as shown below. Figure 1 Four composite beam MEMS switches, located at the top left, top right, bottom left, and bottom right respectively.

[0061] Mode 1: The composite beam MEMS switch is off at the top left, top right, bottom left, and bottom right.

[0062] Mode 2: Composite beam MEMS switch: Top left and top right are on, bottom left and bottom right are off.

[0063] Mode 3: Composite beam MEMS switch - bottom left and bottom right are on, top left and top right are off.

[0064] Appendix Figure 6 The display shows the antenna gain pattern in three modes. The control switch array is switched on and off to achieve three-beam pointing switching of -40°, 0° and +40° in modes 00, 01 and 10 respectively. The main lobe widths in the three modes are 55.61°, 58.94° and 98.56° respectively, supporting wide-angle coverage.

[0065] The above is just one example. To obtain a terahertz broadband pattern reconfigurable antenna with different center frequencies, different parameters can be adjusted according to the specific implementation method to achieve different operating frequency bands and guiding effects.

[0066] It should be understood that the above description of the specific embodiments of this patent is merely an exemplary description provided to facilitate understanding of the patent solution by those skilled in the art, and does not imply that the scope of protection of this patent is limited to these specific examples. Those skilled in the art can obtain more specific embodiments without any creative effort by combining technical features, replacing some technical features, adding more technical features, etc., of the various examples listed in this patent, provided that they have a full understanding of the technical solution of this patent. All of these specific embodiments are within the scope of the claims of this patent, and therefore, these new specific embodiments should also be within the scope of protection of this patent.

Claims

1. A reconfigurable terahertz pattern antenna based on RF-MEMS switching, comprising a dielectric substrate (15) and a metal ground backplane (16), wherein the metal ground backplane (16) is located on the lower surface of the substrate; characterized in that, The upper surface of the dielectric substrate is provided with a composite beam ohmic contact MEMS switch (2), a coplanar waveguide (4), a microstrip transmission line (5), a parasitic patch (3) and a radiating patch (1). The radiating patch (1) is located on one side of the coplanar waveguide (4); the coplanar waveguide (4) has a gradient slot on the side near the radiating patch, and the gradient slot extends toward the side away from the radiating patch; the microstrip transmission line (5) is in the form of a straight line, with one end connected to the radiating patch and the other end located at the bottom edge of the gradient slot, and not in contact with the bottom edge. Two parasitic patches (3) are provided, located on both sides of the radiating patch (1) and parallel to the microstrip transmission line (5); each parasitic patch is a segmented strip patch, and adjacent segmented patches are connected by a composite beam ohmic contact MEMS switch (2); The composite beam ohmic contact MEMS switch (2) includes an upper beam structure, piers and electrodes; wherein the upper beam structure spans the strip patch, and the two ends of the upper beam structure are respectively connected to the piers on both sides of the strip patch; The upper beam structure includes a silica beam, a switch beam, and an actuating beam, wherein the switch beam and the actuating beam are both metal; the switch beam is connected to the actuating beam through the silica beam, and there is no electrical contact between the switch beam and the actuating beam, while the actuating beam and the bridge pier have electrical contact; when the actuating beam moves, it drives the switch beam to move in the same direction. There is a break between two adjacent segment patches; the switch beam is located directly above the break. Each moving beam has an electrode underneath, and the upper surface of the electrode has a silicon nitride electrode insulating layer.

2. The RF-MEMS-based terahertz pattern reconfigurable antenna according to claim 1, characterized in that, The inner edges of the gradient gap are stepped, and the distance between the inner edges gradually decreases from the opening to the bottom edge.

3. The RF-MEMS-based terahertz pattern reconfigurable antenna according to claim 1, characterized in that, The parasitic patch and the radiating patch are located on the same side of the coplanar waveguide.

4. The RF-MEMS-based terahertz pattern reconfigurable antenna according to claim 1, characterized in that, The dielectric substrate (15) is made of quartz glass with a dielectric constant of 3.78 and a loss tangent of 0.0008.

5. The RF-MEMS-based terahertz pattern reconfigurable antenna according to claim 1, characterized in that, A rectangular slot is provided on the side of the radiating patch near the coplanar waveguide; the rectangular slot is directly opposite the gradient gap, and one end of the microstrip transmission line (5) extends into the rectangular slot and connects to the radiating patch.

6. The RF-MEMS-based terahertz pattern reconfigurable antenna according to claim 1, characterized in that, The width of the adjacent ends of the segmented patch gradually narrows.

7. The RF-MEMS-based terahertz pattern reconfigurable antenna according to claim 1, characterized in that, It also includes contacts; the contacts are located on the lower surface of the switch beam, and when the composite beam ohmic contact MEMS switch is in the on state, the contacts abut against the top of the corresponding segment patch.

8. The RF-MEMS-based terahertz pattern reconfigurable antenna according to claim 1, characterized in that, It also includes surface mount pads; each strip-shaped patch corresponds to two surface mount pads; one surface mount pad is connected to the pier, and the other surface mount pad is connected to the electrode.

9. The RF-MEMS-based terahertz pattern reconfigurable antenna according to claim 1, characterized in that, The silica beam has through holes.

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