A W-band broadband RF MEMS multi-pole multi-throw switch

Abstract

The application relates to the technical field of radio frequency microwave devices, in particular to a W-waveband wide-frequency RF MEMS multi-blade multi-pole switch which comprises a silicon substrate, a plurality of input / output ports and a MEMS cantilever beam switch unit, the MEMS cantilever beam switch unit is provided with a driving electrode, and the communication and disconnection of the radio frequency signal path between the corresponding input port and the output port can be controlled by applying voltage to the driving electrode. The application realizes the on-off of the radio frequency signal path by electrostatic driving control of the deformation of the cantilever beam, and the driving mode has the advantages of low power consumption, high speed and easy integration. Compared with the common single-blade structure, the application can realize more complex signal routing in a compact unit, improves the system integration and functional flexibility, realizes interference-free crossing by using the slot structure through the horizontal swing type structure and the vertical lifting type structure, significantly reduces the high-frequency parasitic effect, and ensures the transmission quality of the millimeter wave signal in the W waveband.

Description

Technical Field

[0001] This application relates to the field of radio frequency microwave device technology, and in particular to a W-band broadband RF MEMS multi-pole multi-throw switch. Background Technology

[0002] In the field of radio frequency microwave communication and detection, RF MEMS switches, as core devices for signal path switching, directly determine the signal transmission quality, integration, and reliability of the system. With the evolution of communication technology towards 5G / 6G, and the rapid development of millimeter-wave radar, satellite communication, and other fields, higher requirements are placed on the operating frequency band, bandwidth, port scalability, and radio frequency performance of RF MEMS switches.

[0003] In existing technologies, RF MEMS switches mainly suffer from the following shortcomings: First, their operating frequency band is limited; most multi-pole multi-throw switches can only cover the K-band (DC-26.5GHz), making it difficult to meet the wideband application requirements of the W-band (75-110GHz). Second, their radio frequency performance is poor; traditional switches are inadequate in key indicators such as insertion loss, isolation, and VSWR, resulting in high energy loss and severe interference during signal transmission. Third, their structural design has limitations; horizontal swing cantilever beam switches are prone to contact instability due to contact misalignment, and crosstalk risk is high when signal paths are intersected, while conventional vertical structures suffer from low driving efficiency and poor compatibility. Fourth, their port expandability and functional flexibility are insufficient, making it difficult to adapt to the complex path switching requirements of multi-input multi-output systems.

[0004] Therefore, a W-band broadband RF MEMS multi-pole multi-throw switch is provided to offer a new solution to the aforementioned technical problems. Summary of the Invention

[0005] To address the problems mentioned in the background art, this application provides a W-band broadband RF MEMS multi-pole multi-throw switch.

[0006] The W-band broadband RF MEMS multi-pole multi-throw switch provided in this application adopts the following technical solution:

[0007] A W-band broadband RF MEMS multi-pole multi-throw switch includes a silicon substrate, multiple input and output ports, and a MEMS cantilever beam switch unit. The MEMS cantilever beam switch unit is equipped with a driving electrode. By applying a voltage to the driving electrode, the connection and disconnection of the RF signal path between the corresponding input port and the output port can be controlled.

[0008] Optionally, the MEMS cantilever beam switch unit is configured as a horizontally swinging cantilever beam switch structure, which includes four input / output ports and four MEMS cantilever beam switch units, forming a double-pole double-throw switch architecture; the four input / output ports are port one, port two, port three and port four; the driving electrodes of the four MEMS cantilever beam switch units are electrode one, electrode two, electrode three and electrode four.

[0009] Optionally, the four input / output ports and the driving electrode are all disposed on the top of the silicon substrate. The horizontally swinging cantilever beam structure includes cantilever beam one, cantilever beam two, cantilever beam three, and cantilever beam four, wherein: cantilever beam one is provided on port one and above electrode one, and the end of cantilever beam one crosses electrode one and extends above port three; cantilever beam two is provided on port four and above electrode two, and the end of cantilever beam two crosses electrode two and extends above port two; cantilever beam three is provided on port one and above electrode four, and the end of cantilever beam three crosses electrode four and extends above port four; cantilever beam four is provided on port three and above electrode three, and the end of cantilever beam four crosses electrode three and extends above port two.

[0010] Optionally, the cantilever beam is provided with a moving contact, and the input / output port is provided with a fixed contact; the cantilever beam undergoes elastic deformation under the action of electrostatic force generated by the driving electrode, causing the moving contact to contact or separate from the fixed contact, thereby realizing the switching on and off of the radio frequency signal path.

[0011] Optionally, a recessed groove structure is formed on the silicon substrate, and at least part of the radio frequency signal path is arranged in the groove structure; through the high and low arrangement of the groove structure and the substrate plane, the first radio frequency signal path and the second radio frequency signal path are arranged in a space without interference.

[0012] Optionally, the circuit control logic of the switch is as follows: control electrode one is energized to achieve conduction between port one and port three; control electrode two is energized to achieve conduction between port four and port two; control electrode three is energized to achieve conduction between port three and port two; control electrode four is energized to achieve conduction between port one and port four.

[0013] Optionally, the MEMS cantilever beam switch unit is configured as a vertical lifting cantilever beam switch structure. This structure includes four input / output ports. The four ports are arranged in pairs and layered on the upper and lower end faces of the silicon substrate. The upper and lower layers of ports are arranged crosswise, forming a cross node at the crossover point. A parallel node is formed between the two ports in each layer. A vertical guide hole is formed on the silicon substrate at the cross node and the parallel node. An insulating layer is first deposited on the inner wall of the vertical guide hole, and then a lubricating layer is coated on it. A vertical lifting cantilever beam switch is installed inside the vertical guide hole. Each vertical lifting cantilever beam switch is connected to an independent electrode for driving the vertical lifting cantilever beam switch to move vertically.

[0014] Optionally, the vertical lifting cantilever beam switch includes a lifting column assembly and a vertical drive electrode structure; the vertical drive electrode structure includes an annular comb-shaped electrode connected to the electrode, the surface of the annular comb-shaped electrode is coated with a high dielectric coating, the annular comb-shaped electrode is provided with a plurality of fixed comb teeth, and a miniature electromagnetic coil is embedded in the center of the annular comb-shaped electrode; the lifting column assembly includes a lifting column body, the middle of the lifting column body is provided with an annular corrugated buffer layer, the lifting column body and the vertical guide hole are provided with a fitting gap, the bottom of the lifting column body is provided with a plurality of movable comb teeth, and the fixed comb teeth are staggered with the movable comb teeth at the bottom of the lifting column body.

[0015] Optionally, the top of the lifting column body is provided with a contact ball, and at least two elastic claws are evenly arranged around the contact ball, forming an umbrella shape. The elastic claws can achieve adaptive deflection within a range of ±5°. The outer surfaces of the contact ball and the elastic claws are coated with a wear-resistant conductive coating.

[0016] Optionally, the bottom of the lifting column body of the vertical lifting cantilever beam switch located at the intersection node is electrically connected to the port located at its bottom via a wire to form a complete radio frequency signal transmission path.

[0017] In summary, this application includes at least one of the following beneficial technical effects:

[0018] 1. The switch of this invention is specifically optimized for the W-band (75-110GHz), effectively covering this wide frequency range. Through a horizontal swing structure and a vertical lift structure, it utilizes a slot structure to achieve interference-free crossing, significantly reducing high-frequency parasitic effects. For example... Figures 2 to 4 The simulation or measured results shown indicate that the switch exhibits low insertion loss, low VSWR, and high isolation in the W-band, ensuring the transmission quality of millimeter-wave signals.

[0019] 2. This invention employs a horizontally swinging cantilever beam structure. By optimizing the cantilever beam layout, it achieves a direct and compact connection of the signal path, reducing the channel path length and parasitic parameters.

[0020] 3. This invention adopts a vertical lifting cantilever beam switch structure, using annular comb-shaped electrodes combined with miniature electromagnetic coils, which significantly improves the driving force density. It can achieve fast switching of ≤2μs under a low driving voltage of 8-10V, balancing low power consumption and high-speed response. The umbrella-shaped elastic claw design on the top of the vertical lifting switch allows the contacts to self-adaptively deflect within a certain angle, effectively compensating for processing and alignment errors. Combined with a wear-resistant conductive coating, it greatly improves the reliability and stability of the contact and the service life of the switch, adapting to high-frequency switching operations. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the horizontal swing cantilever beam switch structure of the present invention.

[0022] Figure 2 This is a single-channel insertion loss diagram of the present invention.

[0023] Figure 3 This is the single-ended standing wave ratio diagram of the present invention.

[0024] Figure 4 This is an isolation diagram between adjacent ports of the present invention.

[0025] Figure 5 This is a schematic diagram of the vertical lifting cantilever beam switch structure of the present invention. Figure 1 .

[0026] Figure 6 This is a schematic diagram of the vertical lifting cantilever beam switch structure of the present invention. Figure 2 .

[0027] Figure 7 This is a schematic diagram of the distribution of port five of the present invention.

[0028] Figure 8 This is a schematic diagram of the independent electrode and vertical lifting cantilever beam switch of the present invention.

[0029] Figure 9 This is an exploded structural diagram of the vertical lifting cantilever beam switch of the present invention.

[0030] Figure 10 This is a schematic diagram of the structure of the insulating layer and the lubricating layer of the present invention. Detailed Implementation

[0031] To enable those skilled in the art to better understand the technical solution of the present invention, the following will be described in conjunction with the appendix. Figure 1-10 The present invention will now be described in further detail. Example

[0032] Reference Figure 1-4 This application provides a W-band broadband RF MEMS multi-pole multi-throw switch, including a silicon substrate 1, four input / output ports (port 1, port 2, port 2, port 3, port 4, port 4, and port 5), and four MEMS cantilever beam switch units. Each switch unit consists of a driving electrode (electrode 1, electrode 2, electrode 3, and electrode 4, and electrode 9) and a corresponding cantilever beam (cantilever beam 1, cantilever beam 2, cantilever beam 3, and cantilever beam 4, and cantilever beam 4, and cantilever beam 5).

[0033] By controlling the deformation of the cantilever beam through electrostatic drive, the on / off state of the radio frequency signal path can be achieved. This driving method has the advantages of low power consumption, high speed, and easy integration. Compared with the common single-pole structure, it can realize more complex signal routing in a compact unit, improving system integration and functional flexibility.

[0034] It adopts a dual-blade dual-throw architecture, with four ports corresponding to four driving electrodes. The structure is compact and the layout is regular, which facilitates integrated processing. The independent driving electrode design provides a basis for individual control of each channel, avoids mutual interference between channels, and reduces control complexity.

[0035] All four ports and four electrodes are fabricated on top of the silicon substrate 1. One end of a cantilever beam is anchored to a port, its main body is suspended above the corresponding drive electrode, and its free end extends above the target port. For example, cantilever beam 14 is anchored to port 2, crosses electrode 6, and its free end extends above port 4. Moving contacts are integrated on the cantilever beam, and fixed contacts are provided on the ports.

[0036] The cantilever beams extend across the electrodes to above the target port, shortening the signal transmission path and reducing energy loss; the layout of each cantilever beam does not interfere with each other, ensuring no mechanical conflict when multiple paths are switched simultaneously, thus improving the structural stability and space utilization.

[0037] When it is necessary to connect two ports, a driving voltage is applied to the corresponding driving electrodes. The electrostatic force generated by the electrodes attracts the upper cantilever beam to undergo downward elastic deformation, causing the moving contact at its free end to make close contact with the fixed contact of the target port, forming a radio frequency signal path. After the voltage is removed, the cantilever beam returns to its original position due to its own elasticity, and the path is broken.

[0038] The moving and fixed contacts are precisely matched, and the electrostatic force drives the elastic deformation, resulting in rapid switching response. The elastic restoring force of the cantilever beam ensures reliable reset, avoids contact sticking, minimizes contact resistance fluctuations, and improves signal transmission consistency and switch lifespan.

[0039] A recessed trench structure 18 is fabricated on a silicon substrate 1 using a deep etching process. Some coplanar waveguide transmission lines can be laid within the trench, while others are on the plane. This undulating layout ensures that, for example, the path from port 1 to port 3 and the path from port 4 to port 2 at their spatial intersections are one in the trench and the other on the plane, effectively avoiding the strong coupling caused by traditional planar intersections and improving the isolation between ports.

[0040] By using the varying heights of the slot structure and the base plane, spatial intersection of signal paths is achieved, solving the problem of electromagnetic crosstalk between intersection paths; wiring within the slot reduces signal leakage, further improving the isolation between adjacent paths and adapting to complex switching requirements of multiple paths.

[0041] During control, applying voltage to electrode 6 causes cantilever beam 14 to engage, connecting port 2 and port 4. Applying voltage to electrode 7 causes cantilever beam 17 to engage, connecting port 5 and port 3. Applying voltage to electrode 8 causes cantilever beam 15 to engage, connecting port 4 and port 3. Applying voltage to electrode 9 causes cantilever beam 16 to engage, connecting port 2 and port 5.

[0042] By adopting the above technical solution, the path control logic is clear and explicit, and a single electrode independently controls the conduction of a group of ports, making operation convenient; it supports parallel conduction of multiple paths or individual switching, meeting the signal path configuration requirements in different scenarios, and is highly flexible.

[0043] By optimizing the cantilever beam size, contact materials (such as gold plating), and transmission line design, this switch achieves a single-channel insertion loss better than 1dB, a VSWR of less than 1.5, and an adjacent port isolation greater than 35dB in the 75-110GHz frequency band. Example

[0044] Reference Figures 5 to 10 This embodiment provides a W-band RF MEMS switch architecture suitable for higher density integration.

[0045] Two ports 19 are fabricated on each of the upper and lower end faces of the silicon substrate 1, for a total of four ports. The two upper ports are arranged side by side, and the two lower ports are arranged front and back, forming an intersection in the top view. Vertical guide holes 20 are etched at the intersection points and the corresponding silicon substrate positions of each side-by-side point.

[0046] The layered and parallel port layout, combined with the cross-layout, significantly improves space utilization and saves the area occupied by the silicon substrate. The composite structure of the insulating and lubricating layers of the vertical guide holes avoids the risk of leakage and reduces lifting friction, ensuring smooth and stable vertical lifting, and is suitable for high-density integration scenarios.

[0047] Each vertical guide hole 20 houses an independent vertical lifting cantilever switch 23. An insulating layer 22 (such as a silicon oxide insulating layer) is first deposited on the inner wall of the guide hole, followed by a lubricating layer 21 (such as a diamond-like carbon film, aluminum nitride lubricating layer, etc.) to reduce friction and prevent short circuits, ensuring smooth lifting and translation. Each switch is connected to an independent electrode 24.

[0048] The driving section employs annular comb-shaped electrodes 25, with a high-dielectric coating on their surface to enhance the electric field. Fixed comb teeth 26 are provided on the annular comb-shaped electrodes 25, and a miniature electromagnetic coil 27 is embedded in its center. Movable comb teeth 29 are provided at the bottom of the lifting column body 28, interlocking with the fixed comb teeth 26. During operation, a voltage is first applied to the comb-shaped electrodes to generate electrostatic force for activation, and then a pulsed current is applied to the miniature electromagnetic coil 27 to generate magnetic assistance, forming a powerful composite driving force that propels the lifting column body 28 vertically within the guide hole. An annular corrugated buffer layer 30 in the middle of the lifting column body 28 absorbs the impact stress of the movement.

[0049] The system employs a combination of electrostatic and electromagnetic drive with staggered comb teeth to maximize the driving force density, reduce the driving voltage to 8-10V, and achieve a switching speed of ≤2μs, thus balancing low power consumption and fast response. The buffer layer absorbs longitudinal stress, and the reasonable gap between the layers prevents the lifting column from breaking or jamming, thereby improving structural reliability.

[0050] In a preferred embodiment, the surface of the annular comb electrode 25 is coated with a hafnium oxide high-dielectric coating (dielectric constant 20-25), which increases the breakdown voltage from 30V to 50V, thus avoiding electrode breakdown in W-band high-frequency and high-voltage scenarios.

[0051] The top of the lifting column body 28 is a contact ball 31, surrounded by multiple elastically deformable claws 32, forming an overall umbrella shape. The surface of the elastic claws 32 is coated with a wear-resistant conductive layer. When the lifting column rises, the umbrella-shaped structure can adaptively fit the upper port to ensure good contact.

[0052] A titanium-tungsten alloy annular corrugated buffer layer is integrated in the middle of the lifting column to replace the root hinge of the traditional cantilever beam. On the one hand, it absorbs the longitudinal impact stress during the lifting process, such as the contact impact force when the beam is connected. On the other hand, it compensates for minor processing errors, such as slight tilting of the guide hole, to prevent the lifting column from breaking.

[0053] The elastic claw can deflect ±5° to compensate for minor alignment deviations (≤0.5μm) that may occur during translation, ensuring that even if the lifting column is slightly tilted, the elastic claw can still contact the port contact simultaneously, avoiding single-point contact offset of traditional swing structures.

[0054] The umbrella-shaped elastic claw can achieve adaptive deflection, compensate for machining and assembly deviations, and ensure reliable contact. The wear-resistant conductive coating reduces the wear rate, extends the service life of the contacts, and stabilizes the contact resistance, making it suitable for high-frequency on-off cycle scenarios.

[0055] For a vertical switch located at the intersection of upper and lower ports, the bottom of its rising column body 28 is electrically connected to the corresponding port 19 located on the bottom of the silicon substrate via gold wire bonding or thin-film wires. When the rising column of the switch rises, its umbrella-shaped contact at the top contacts the upper port, thereby connecting the two corresponding intersection ports on the upper and lower layers.

[0056] By independently controlling the lifting and lowering of each vertical switch, the connection between any upper and lower ports can be flexibly configured. This vertical layering and three-dimensional control method greatly saves planar area and facilitates expansion into switch matrices with more ports. Composite drive ensures fast and reliable operation at low voltages, while umbrella-shaped contacts guarantee stable contact at high frequencies.

[0057] When conduction is required at port five at the cross node, an 8-10V driving voltage is applied to the corresponding independent electrode: the annular comb-shaped electrode generates electrostatic force, and the fixed comb teeth 26 and the movable comb teeth 29 interlock to generate a vertical driving force. At the same time, a momentary pulse current (pulse width 1-2μs) is passed through the micro electromagnetic coil 27, generating a magnetic attraction force that is superimposed with the electrostatic force, driving the lifting column body 28 to rise vertically along the vertical guide hole. The umbrella-shaped elastic claw 32 and the contact ball 31 at the top of the lifting column body 28 contact the fixed contact of the upper port five 19. The elastic claw 32 adaptively deflects to compensate for the alignment deviation, forming a reliable electrical connection. The radio frequency signal is transmitted through the upper port five 19, the contact, the lifting column body 28, the wire, and the lower port five 19. After the voltage is removed, a reverse pulse current is passed through the micro electromagnetic coil 27 to generate a repulsive force. The elastic restoring force of the annular corrugated buffer layer 30 pushes the lifting column body 28 to fall vertically, the contact separates, and the circuit is broken. The path control logic at parallel nodes is consistent with that at cross nodes. By independently driving the corresponding vertical lifting cantilever beam switch 23, flexible switching between any input and output ports can be achieved.

[0058] At the crossover node, the wires directly connect the rising column and the bottom port, forming a complete transmission path, reducing signal transmission links and insertion loss; the electrical connection is reliable, avoiding signal leakage and ensuring the transmission quality and isolation of the crossover path.

[0059] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A W-band broadband RF MEMS multi-pole multi-throw switch, comprising a silicon substrate (1), multiple input / output ports, and a MEMS cantilever switch unit, characterized in that, The MEMS cantilever beam switch unit is equipped with a driving electrode. By applying a voltage to the driving electrode, the connection and disconnection of the radio frequency signal path between the corresponding input port and the output port can be controlled. The MEMS cantilever beam switch unit is configured as a horizontal swing cantilever beam switch structure, which includes four input / output ports and four MEMS cantilever beam switch units, forming a double-pole double-throw switch architecture; the four input / output ports are port one (2), port two (3), port three (4) and port four (5); the driving electrodes of the four MEMS cantilever beam switch units are electrode one (6), electrode two (7), electrode three (8) and electrode four (9); The four input / output ports and the driving electrode are all disposed on the top of the silicon substrate (1). The horizontal swing cantilever beam structure includes cantilever beam one (14), cantilever beam two (17), cantilever beam three (16) and cantilever beam four (15), wherein: cantilever beam one (14) is provided on port one (2) and above electrode one (6), and the end of cantilever beam one (14) crosses electrode one (6) and extends to above port three (4); cantilever beam four (5) is provided on port four (5) and above electrode two (7). Second (17), the end of the second cantilever beam (17) crosses over the second electrode (7) and extends above the second port (3); a third cantilever beam (16) is provided on the first port (2) and above the fourth electrode (9), the end of the third cantilever beam (16) crosses over the fourth electrode (9) and extends above the fourth port (5); a fourth cantilever beam (15) is provided on the third port (4) and above the third electrode (8), the end of the fourth cantilever beam (15) crosses over the third electrode (8) and extends above the second port (3); The circuit control logic of the switch is as follows: control electrode one (6) is energized to realize the conduction of port one (2) and port three (4); control electrode two (7) is energized to realize the conduction of port four (5) and port two (3); control electrode three (8) is energized to realize the conduction of port three (4) and port two (3); control electrode four (9) is energized to realize the conduction of port one (2) and port four (5).

2. The W-band broadband RF MEMS multi-pole multi-throw switch according to claim 1, characterized in that: The cantilever beam is provided with a moving contact, and the input / output port is provided with a fixed contact. The cantilever beam undergoes elastic deformation under the action of electrostatic force generated by the driving electrode, which causes the moving contact to contact or separate from the fixed contact, thereby realizing the switching on and off of the radio frequency signal path.

3. A W-band broadband RF MEMS multi-pole multi-throw switch according to claim 2, characterized in that: The silicon substrate (1) has a recessed groove structure (18) and at least part of the radio frequency signal path is arranged in the groove structure (18). Through the high and low arrangement of the groove structure (18) and the substrate plane, the first radio frequency signal path and the second radio frequency signal path are arranged in a space without interference.

4. A W-band broadband RF MEMS multi-pole multi-throw switch according to claim 1, characterized in that: The MEMS cantilever beam switch unit is configured as a vertical lifting cantilever beam switch structure, which includes four input / output ports (19). The four ports (19) are arranged in pairs and layered on the upper and lower end faces of the silicon substrate (1). The upper and lower layers of ports (19) are arranged in a cross pattern and form a cross node at the cross point. A parallel node is formed between the two ports (19) in each layer. A vertical guide hole (20) is provided on the silicon substrate (1) at the cross node and the parallel node. An insulating layer (22) is first deposited on the inner wall of the vertical guide hole (20), and then a lubricating layer (21) is coated. A vertical lifting cantilever beam switch (23) is installed inside the vertical guide hole (20). Each vertical lifting cantilever beam switch (23) is connected to an independent electrode (24) for driving the vertical lifting cantilever beam switch (23) to move vertically. The vertical lifting cantilever beam switch (23) includes a lifting column assembly and a vertical drive electrode structure; the vertical drive electrode structure includes an annular comb electrode (25) connected to the independent electrode (24), the surface of the annular comb electrode (25) is coated with a high dielectric coating, the annular comb electrode (25) is provided with a plurality of fixed comb teeth (26), and a miniature electromagnetic coil (27) is embedded in the center of the annular comb electrode (25); the lifting column assembly includes a lifting column body (28), the middle part of the lifting column body (28) is provided with an annular corrugated buffer layer (30), the lifting column body (28) and the vertical guide hole (20) are provided with a fitting gap, the bottom of the lifting column body (28) is provided with a plurality of movable comb teeth (29), and the fixed comb teeth (26) and the movable comb teeth (29) at the bottom of the lifting column body (28) are staggered and engaged; The top of the lifting column body (28) is provided with a contact ball (31), and at least two elastic claws (32) are evenly arranged around the contact ball (31). The whole is umbrella-shaped. The elastic claws (32) can achieve adaptive deflection within a range of ±5°. The outer surfaces of the contact ball (31) and the elastic claws (32) are coated with a wear-resistant conductive coating.

5. A W-band broadband RF MEMS multi-pole multi-throw switch according to claim 4, characterized in that: The bottom of the lifting column body (28) of the vertical lifting cantilever beam switch (23) located at the intersection node is electrically connected to the port five (19) located at its bottom via a wire, forming a complete radio frequency signal transmission path.

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