High-isolation low-startup-voltage series-contact dual-beam cantilever mems switch

Abstract

The application discloses a high-isolation low-starting-voltage series contact type double-arm cantilever MEMS switch, which comprises a substrate, a first CPW transmission line, a second CPW transmission line, a third CPW transmission line, a first cantilever switch structure and a second cantilever switch structure, the third CPW transmission line is arranged on the substrate and located between the first CPW transmission line and the second CPW transmission line, one end of the first cantilever switch structure is connected with the first CPW transmission line, and the other end is connected with one end of the third CPW transmission line; one end of the second cantilever switch structure is connected with the second CPW transmission line, and the other end is connected with the other end of the third CPW transmission line. The application is applied to the field of microelectronic machinery, effectively reduces the driving voltage by reducing the gap between the upper electrode and the driving electrode, realizes high isolation through the series single-cantilever switch two-stage cascade mode, and makes the MEMS switch better support the application of the radio frequency system.

Description

Technical Field

[0001] This invention relates to the field of radio frequency microelectromechanical systems (MEMS) technology, specifically a high-isolation, low-start-voltage series contact double-arm cantilever MEMS switch. Background Technology

[0002] Radio frequency (RF) switches are widely used in many fields, including integrated circuit design, due to their unique advantages. In integrated circuit design, the high isolation of RF switches can reduce the mutual interference between components, thereby improving the performance of the integrated circuit, while the low drive voltage can reduce power consumption, thus reducing the design cost of the integrated circuit. Because of their function in controlling the conversion of microwave signal channels, RF switches are frequently used in the design of RF paths and play a crucial role. Furthermore, RF switches are also used in satellite communication systems or hubs as signal conversion units.

[0003] Currently, the switching circuits widely used in integrated circuits are traditional radio frequency MEMS switches. This type of switch adopts a single cantilever structure, as shown below. Figure 1 As shown. The switch includes a circuit substrate 001, an input / output CPW transmission line 002 connected to other RF circuits, a driving electrode 003, an upper electrode 004, an insulating layer 005 between the two electrodes, and a contact point 006 between the upper and lower electrodes when the switch is on. When the switch is working, the voltage signal on the driving electrode serves as a control signal to control the on / off state of the switch. When the driving voltage is 0, the upper electrode separates from the contact point, and the CPW transmission lines on both sides are disconnected, meaning the switch is in the off state. As the driving voltage gradually increases, the right end of the upper electrode gradually approaches the contact point due to gravity. When the driving voltage reaches the switch closing voltage, the right end of the upper electrode contacts the contact point, the left and right CPW transmission lines are connected together, and the switch is in the closed state. When the driving voltage disappears, the right end of the upper electrode of the switch is pulled up again to return to its original state, and the switch is off again.

[0004] For RF switches, the most important performance parameters are isolation, insertion loss, return loss, and drive voltage. Figure 1For single-cantilever MEMS switches, the drive voltage controls the switching on and off, and the switch performance is mainly determined by the electrode parameters. The distance between the upper electrode and the drive electrode must be large enough to ensure weak signal coupling through the "upper electrode-contact point" coupling path, minimizing coupling between the CPW transmission lines at both ends when the switch is open, thus achieving high isolation when the switch is open. However, increasing the distance between the upper electrode and the drive electrode introduces other problems, such as a significant increase in the drive voltage required for the upper electrode to contact the contact point, leading to an excessively high drive voltage when the switch is closed. Reducing the gap between the drive electrode and the upper electrode can effectively lower the drive voltage, but this significantly reduces the isolation between the input and output terminals. Traditional single-cantilever MEMS switches require drive voltages of 10V or even higher to achieve high isolation, but their drive circuits are complex, making it difficult to simultaneously achieve high isolation and low drive voltage. Summary of the Invention

[0005] To address the issue of high driving voltage in traditional single-cantilever RF MEMS switches in the prior art, this invention provides a high-isolation, low-start-voltage series contact double-cantilever MEMS switch that can simultaneously achieve high isolation and low driving voltage, enabling the designed RF MEMS switch to better support RF system applications.

[0006] To achieve the above objectives, the present invention provides a high-isolation, low-start-voltage series contact double-arm cantilever MEMS switch, including a substrate and a first CPW transmission line and a second CPW transmission line spaced apart on the substrate.

[0007] It also includes a third CPW transmission line, a first cantilever switch structure and a second cantilever switch structure, wherein the third CPW transmission line is disposed on the substrate and spaced between the first CPW transmission line and the second CPW transmission line;

[0008] One end of the first cantilever switch structure is connected to the first CPW transmission line, and the other end of the first cantilever switch structure is connected to one end of the third CPW transmission line.

[0009] One end of the second cantilever switch structure is connected to the second CPW transmission line, and the other end of the second cantilever switch structure is connected to the other end of the third CPW transmission line.

[0010] In one embodiment, the first cantilever switch structure includes a first anchor point, a first driving electrode, a first upper electrode, and a first contact point;

[0011] The first driving electrode is disposed on the substrate, and the first driving electrode is spaced between the first CPW transmission line and the third CPW transmission line;

[0012] The first anchor point is located at one end of the first CPW transmission line facing the third CPW transmission line, and the first contact point is located at one end of the third CPW transmission line facing the first CPW transmission line.

[0013] One end of the first upper electrode is connected to the first anchor point, and the other end is located directly above the first contact point, while the first driving electrode is located directly below the middle of the first upper electrode.

[0014] In one embodiment, the second cantilever switch structure includes a second anchor point, a second drive electrode, a second upper electrode, and a second contact point;

[0015] The second driving electrode is disposed on the substrate, and the second driving electrode is spaced between the second CPW transmission line and the third CPW transmission line;

[0016] The second anchor point is located at one end of the second CPW transmission line facing the third CPW transmission line, and the second contact point is located at one end of the third CPW transmission line facing the second CPW transmission line.

[0017] One end of the second upper electrode is connected to the second anchor point, and the other end is located directly above the second contact point, while the second driving electrode is located directly below the middle of the second upper electrode.

[0018] In one embodiment, the first cantilever switch structure further includes a first insulating layer, and the second cantilever switch structure further includes a second insulating layer;

[0019] The first insulating layer is disposed between the first driving electrode and the first upper electrode, and the second insulating layer is disposed between the second driving electrode and the second upper electrode.

[0020] In one embodiment, the MEMS switch has a left-right symmetrical structure, and the physical structure and size parameters of the symmetrical parts are the same.

[0021] In one embodiment, the design process for the driving voltages of the first driving electrode and the second driving electrode is as follows:

[0022] When a driving voltage is applied to the driving electrode, the upper electrode is subjected to the combined force of electrostatic force and deformation mechanical restoring force.

[0023] The electrostatic force F e for:

[0024]

[0025] In the formula, V is the driving voltage applied to the driving electrode, C(g) is the distance between the two electrodes when the gap between the driving electrode and the upper electrode is g, ε is the dielectric constant of air, and A is the area of ​​the driving electrode and the upper electrode facing each other.

[0026] The deformation mechanical restoring force F0 is:

[0027] F0=kx

[0028] In the formula, k is the elastic coefficient of the free end of the upper electrode, and x is the displacement of the free end of the upper electrode.

[0029] When the electrostatic force matches the deformation mechanical restoring force, the driving voltage at this time can be obtained as follows:

[0030]

[0031] In the formula, g0 is the initial gap between the driving electrode and the upper electrode;

[0032] definition The voltage corresponding to this time is the critical driving voltage, and the driving voltage can be obtained as follows:

[0033]

[0034] In the formula, V p t is the driving voltage of the first upper electrode or the second upper electrode, E is the Young's modulus of the material of the first upper electrode or the second upper electrode, t is the thickness of the material of the first upper electrode or the second upper electrode, w is the width of the first upper electrode or the second upper electrode, and l is the length of the first upper electrode or the second upper electrode.

[0035] In one embodiment, the first driving electrode, the second driving electrode, the first CPW transmission line, the second CPW transmission line, and the third CPW transmission line are all made of copper;

[0036] Both the first upper electrode and the second upper electrode are made of gold.

[0037] In one embodiment, the substrate is made of quartz, GaN, or GaAs.

[0038] This invention provides a high-isolation, low-start-voltage series-contact double-arm cantilever MEMS switch. The series-contact double-arm cantilever MEMS switch is obtained by connecting two single-arm MEMS switches with reduced electrode gaps in series. By reducing the gap between the upper electrode and the driving electrode, the driving voltage is effectively reduced. At the same time, high isolation is achieved by cascading two stages of series single-arm switches, so that the designed RF MEMS switch can better support the application of RF systems. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0040] Figure 1 This is a schematic diagram of the structure of a traditional radio frequency MEMS switch in the prior art;

[0041] Figure 2 This is a schematic diagram of the open state of the MEMS switch in an embodiment of the present invention;

[0042] Figure 3 This is a schematic diagram of the closed state of the MEMS switch in an embodiment of the present invention;

[0043] Figure 4 This is a schematic diagram of electrostatic force and deformation mechanical restoring force in an embodiment of the present invention;

[0044] Figure 5 This is a schematic diagram illustrating the variation of the critical driving voltage with the gap between the two electrodes in an embodiment of the present invention;

[0045] Figure 6 This is a schematic diagram of the MEMS switch dimensions as exemplified in an embodiment of the present invention;

[0046] Figure 7 This is a simulation result diagram of the switch in the open state in an embodiment of the present invention;

[0047] Figure 8 The figure shows the simulation results of the switch in the closed state in an embodiment of the present invention.

[0048] Icon labels:

[0049] Circuit substrate 001, input / output terminal CPW transmission line connected to other RF circuits 002, driving electrode 003, upper electrode 004, insulating layer between the two electrodes 005, contact point of the upper and lower electrodes when conducting 006;

[0050] Substrate 1, first CPW transmission line 2, second CPW transmission line 3, third CPW transmission line 4, first anchor point 501, first driving electrode 502, first upper electrode 503, first contact point 504, first insulating layer 505, second anchor point 601, second driving electrode 602, second upper electrode 603, second contact point 604, second insulating layer 605.

[0051] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0052] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0053] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0054] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0055] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two elements or the interaction between two elements, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0056] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0057] like Figure 2-3The diagram shows a high-isolation, low-start-voltage series-contact dual-arm cantilever MEMS switch disclosed in this embodiment. It includes a substrate 1 and a first CPW transmission line 2 and a second CPW transmission line 3 spaced apart on the substrate 1. The first CPW transmission line 2 and the second CPW transmission line 3 are used for electrical connection to the input / output terminals of other radio frequency circuits. The MEMS switch also includes a third CPW transmission line 4, a first cantilever switch structure, and a second cantilever switch structure. Specifically:

[0058] The third CPW transmission line 4 is disposed on the substrate 1 and is spaced between the first CPW transmission line 2 and the second CPW transmission line 3. That is, there is a gap between the third CPW transmission line 4 and both the first CPW transmission line 2 and the second CPW transmission line 3, and the length of the gap between the third CPW transmission line 4 and the first CPW transmission line 2 is equal to the length of the gap between the third CPW transmission line 4 and the second CPW transmission line 3. One end of the first cantilever switch structure is connected to the first CPW transmission line 2, and the other end of the first cantilever switch structure is connected to one end of the third CPW transmission line 4; one end of the second cantilever switch structure is connected to the second CPW transmission line 3, and the other end of the second cantilever switch structure is connected to the other end of the third CPW transmission line 4.

[0059] The first cantilever switch structure includes a first anchor point 501, a first driving electrode 502, a first upper electrode 503, a first contact point 504, and a first insulating layer 505. The first driving electrode 502 is fixedly disposed on the substrate 1, and the first driving electrode 502 is spaced between the first CPW transmission line 2 and the third CPW transmission line 4, that is, there is a gap between the first driving electrode 502 and both the first CPW transmission line 2 and the third CPW transmission line 4. The first anchor point 501 is fixedly disposed on the first CPW transmission line 2 and close to the third CPW transmission line 4. The first contact point 504 is fixedly disposed on the third CPW transmission line 4 and close to the first CPW transmission line 2. One end of the first upper electrode 503 is connected to the first anchor point 501, and the other end is located directly above the first contact point 504. The first driving electrode 502 is located directly below the middle of the first upper electrode 503. The first insulating layer 505 is disposed between the first driving electrode 502 and the first upper electrode 503. In specific implementation, the first insulating layer 505 is fixedly covered on the top of the first driving electrode 502.

[0060] The second cantilever switch structure includes a second anchor point 601, a second driving electrode 602, a second upper electrode 603, a second contact point 604, and a second insulating layer 605. The second driving electrode 602 is fixedly disposed on the substrate 1, and is spaced between the second CPW transmission line 3 and the third CPW transmission line 4, that is, there is a gap between the second driving electrode 602 and both the second CPW transmission line 3 and the third CPW transmission line 4. The second anchor point 601 is fixedly disposed on the second CPW transmission line 3 and close to the third CPW transmission line 4. The second contact point 604 is fixedly disposed on the third CPW transmission line 4 and close to the second CPW transmission line 3. One end of the second upper electrode 603 is connected to the second anchor point 601, and the other end is located directly above the second contact point 604. The second driving electrode 602 is located directly below the middle of the second upper electrode 603. The second insulating layer 605 is disposed between the second driving electrode 602 and the second upper electrode 603. In specific implementation, the second insulating layer 605 is fixedly covered on the top of the second driving electrode 602.

[0061] In this embodiment, the substrate 1 is a general-purpose integrated circuit substrate 1, such as one made of quartz, GaN, or GaAs. The first driving electrode 502, the second driving electrode 602, the first CPW transmission line 2, the second CPW transmission line 3, and the third CPW transmission line 4 are all made of copper, the first upper electrode 503 and the second upper electrode 603 are both made of gold, and the first insulating layer 505 and the second insulating layer 605 are made of insulating materials such as Si3N4.

[0062] The MEMS switch in this embodiment has a symmetrical structure, and the physical structure and size parameters of the symmetrical parts are the same. Its working principle is as follows:

[0063] When the switch is activated, two identical voltage signals on the first driving electrode 502 and the second driving electrode 602 serve as control signals to control the on / off state of the switch. When the driving voltage of the first driving electrode 502 and the second driving electrode 602 is 0, the first upper electrode 503 is completely separated from the first contact point 504, and the second upper electrode 603 is completely separated from the second contact point 604, thus disconnecting the first CPW transmission line 2 from the second CPW transmission line 3. In other words, the switch is in the off state. The switch off state structure is as follows: Figure 2As shown; when the two identical driving voltages on the first driving electrode 502 and the second driving electrode 602 gradually increase synchronously, due to the gravitational force, the right end of the first upper electrode 503 (i.e., the free end of the first upper electrode 503) and the left end of the second upper electrode 603 (i.e., the free end of the second upper electrode 603) gradually approach the first contact point 504 and the second contact point 604 to the same degree, respectively; when the two identical driving voltages on the first driving electrode 502 and the second driving electrode 602 reach the switch closing voltage, the right end of the first upper electrode 503 and the left end of the second upper electrode 603 simultaneously contact the first contact point 504 and the second contact point 604, respectively. The first CPW transmission line 2 and the second CPW transmission line 3 are connected together through the first upper electrode 503, the first contact point 504, the third CPW transmission line 4, the second contact point 604, and the second upper electrode 603, and the switch is in the closed state. The switch closed state structure is as follows. Figure 3 As shown; when the two driving voltages on the first driving electrode 502 and the second driving electrode 602 disappear simultaneously, the right end of the first upper electrode 503 and the left end of the second upper electrode 603 are pulled up again to return to their original state, and the switch is turned off again.

[0064] Because a two-stage cascaded dual cantilever switch is used, the gap between the upper electrode and the driving electrode can be significantly reduced, and the driving voltage required for the upper electrode to contact the contact point is also significantly reduced. Therefore, a smaller driving voltage is sufficient to drive the switch into the closed state. Without a driving voltage, the upper electrode and the contact point are close together, and the signal coupled through the "upper electrode-contact point" coupling path of a single switch in the structure is relatively stronger than that of a single cantilever. However, for the symmetrical double-arm cantilever beam structure proposed in this embodiment, the signal coupled through the "upper electrode-contact point-upper electrode" coupling path is still quite weak, meaning the isolation between the two ports of the switch remains high. In summary, the double-arm cantilever beam MEMS switch designed in this invention achieves both low driving voltage and high isolation, making it more promising for applications in radio frequency (RF) applications.

[0065] In this embodiment, the design process for the driving voltage of the first driving electrode 502 and the second driving electrode 602 is as follows:

[0066] When a driving voltage is applied to the driving electrode, the upper electrode experiences a combination of electrostatic force and deformation mechanical restoring force, i.e., as shown below. Figure 4 As shown;

[0067] electrostatic force F e for:

[0068]

[0069] In the formula, V is the driving voltage applied to the driving electrode, C(g) is the distance between the two electrodes when the gap between the driving electrode and the upper electrode is g, ε is the dielectric constant of air, and A is the area of ​​the driving electrode and the upper electrode facing each other.

[0070] The deformation mechanical restoring force is calculated with reference to Hooke's Law, that is, the deformation mechanical restoring force F0 is:

[0071] F0=kx

[0072] In the formula, To apply a concentrated load to the free end, the corresponding elastic modulus is E, the Young's modulus of the upper electrode material is t, the thickness of the upper electrode material is w, the width of the upper electrode is l, the length of the upper electrode is x, and the displacement of the free end of the upper electrode is x.

[0073] When the electrostatic force coincides with the deformation mechanical restoring force, the driving voltage at this time can be obtained as:

[0074]

[0075] In the formula, g0 is the initial gap between the driving electrode and the upper electrode;

[0076] definition The voltage corresponding to this time is the critical driving voltage, and the driving voltages corresponding to different area sizes can be obtained as follows:

[0077]

[0078] In the formula, V p This refers to the driving voltage of the first driving electrode 502 or the second driving electrode 602. Therefore, to reduce the driving voltage, two methods can be used: reducing the gap between the driving electrode and the upper electrode, increasing the thickness of the upper electrode, or increasing the alignment length between the driving electrode and the upper electrode. Figure 5 The diagram shows the change in critical driving voltage with the gap between the driving electrode and the upper electrode. The simulation used a 1.5µm thick upper electrode made of gold, with a length of 170µm directly opposite the driving electrode. Figure 5 It can be seen that when g = 2.5um, the critical driving voltage is about 6.5V; when g = 0.5um, the critical driving voltage is about 0.5V.

[0079] The MEMS in this invention will be further explained below with reference to simulation examples.

[0080] like Figure 6As shown in the simulation example, the substrate 1 has a thickness of 100 μm, the first CPW transmission line 2 and the second CPW transmission line 3 both have a thickness of 1.5 μm, the first upper electrode 503 and the second upper electrode 603 both have a length of 320 μm, the first upper electrode 503 and the second upper electrode 603 both have a thickness of 1.5 μm, the length of the first upper electrode 503 facing the first driving electrode 502 and the length of the second upper electrode 603 facing the second driving electrode 602 are both 170 μm, the first insulating layer 505 and the second insulating layer 605 both have a thickness of 0.5 μm, the first anchor point 501 and the second anchor point 601 both have a height of 2 μm, the first contact point 504 and the second contact point 604 both have a height of 0.5 μm, and the first driving electrode 502 and the second driving electrode 602 both have a thickness of 1.5 μm. The gap h between the first upper electrode 503 and the first driving electrode 502 and the gap h between the second upper electrode 603 and the second driving electrode 602 are either 2.5 μm or 0.5 μm.

[0081] Since the MEMS switch in this invention is a reciprocal device, its S-parameter matrix is ​​symmetrical. In the closed state, S21 / S12 represents the transmission characteristics of the switch in the closed state, and S11 and S22 represent the reflection characteristics of the two ports of the switch in the closed state, respectively; in the open state, S21 / S12 represents the isolation of the switch in the open state, and S11 and S22 represent the reflection characteristics of the two ports of the switch in the open state, respectively.

[0082] Simulation results of the switch in the open state are as follows: Figure 7 As shown. By Figure 7 The simulation results show that in the 2-18GHz frequency band, when the gap h = 2.5µm, the switch S21 is less than -15dB, indicating that the switch has high isolation in the open state.

[0083] Simulation results of the switch in the closed state are as follows: Figure 8 As shown. By Figure 8 The simulation results show that in the 2-18GHz frequency band, when the gap h = 0.5µm, the switch S21 is greater than -0.39dB, indicating that the switch has very small insertion loss when closed; S11 is less than -17.5dB, indicating that the switch has very small return loss when closed.

[0084] The simulation results under the two states described above demonstrate that the series-contact double-arm cantilever MEMS switch designed in this invention possesses excellent switching characteristics. The smaller gap between the upper and lower electrodes also enables a low driving voltage. Therefore, the series-contact double-arm cantilever MEMS switch designed in this invention exhibits excellent switching characteristics such as low driving voltage and high isolation, making it suitable for applications in integrated circuit design, RF microwave systems, and other fields.

[0085] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A high-isolation, low-start-voltage series contact double-arm cantilever MEMS switch, comprising a substrate and a first CPW transmission line and a second CPW transmission line spaced apart on the substrate; Its features are, It also includes a third CPW transmission line, a first cantilever switch structure and a second cantilever switch structure, wherein the third CPW transmission line is disposed on the substrate and spaced between the first CPW transmission line and the second CPW transmission line; One end of the first cantilever switch structure is connected to the first CPW transmission line, and the other end of the first cantilever switch structure is connected to one end of the third CPW transmission line. One end of the second cantilever switch structure is connected to the second CPW transmission line, and the other end of the second cantilever switch structure is connected to the other end of the third CPW transmission line. The first cantilever switch structure includes a first anchor point, a first driving electrode, a first upper electrode, and a first contact point; the first driving electrode is disposed on the substrate and is spaced between the first CPW transmission line and the third CPW transmission line; the first anchor point is disposed at one end of the first CPW transmission line facing the third CPW transmission line, and the first contact point is located at one end of the third CPW transmission line facing the first CPW transmission line; one end of the first upper electrode is connected to the first anchor point, the other end is located directly above the first contact point, and the first driving electrode is located directly below the middle of the first upper electrode; The second cantilever switch structure includes a second anchor point, a second driving electrode, a second upper electrode, and a second contact point; the second driving electrode is disposed on the substrate and is spaced between the second CPW transmission line and the third CPW transmission line; the second anchor point is disposed at one end of the second CPW transmission line facing the third CPW transmission line, and the second contact point is located at one end of the third CPW transmission line facing the second CPW transmission line; one end of the second upper electrode is connected to the second anchor point, the other end is located directly above the second contact point, and the second driving electrode is located directly below the middle of the second upper electrode.

2. The high isolation, low start-up voltage series contact double-arm cantilever MEMS switch according to claim 1, characterized in that, The first cantilever switch structure further includes a first insulating layer, and the second cantilever switch structure further includes a second insulating layer; The first insulating layer is disposed between the first driving electrode and the first upper electrode, and the second insulating layer is disposed between the second driving electrode and the second upper electrode.

3. The high isolation, low start-up voltage series contact double-arm cantilever MEMS switch according to claim 1 or 2, characterized in that, The MEMS switch has a left-right symmetrical structure, and the physical structure and size parameters of the symmetrical parts are the same.

4. The high isolation, low start-up voltage series contact double-arm cantilever MEMS switch according to claim 3, characterized in that, The design process for the driving voltages of the first driving electrode and the second driving electrode is as follows: When a driving voltage is applied to the driving electrode, the upper electrode is subjected to the combined force of electrostatic force and deformation mechanical restoring force. The electrostatic force F e for: In the formula, V is the driving voltage applied to the driving electrode, C(g) is the distance between the two electrodes when the gap between the driving electrode and the upper electrode is g, ε is the dielectric constant of air, and A is the area of ​​the driving electrode and the upper electrode facing each other. The deformation mechanical restoring force F0 is: In the formula, k is the elastic coefficient of the free end of the upper electrode, and x is the displacement of the free end of the upper electrode. When the electrostatic force matches the deformation mechanical restoring force, the driving voltage at this time can be obtained as follows: In the formula, g0 is the initial gap between the driving electrode and the upper electrode; definition The voltage corresponding to this time is the critical driving voltage, and the driving voltage can be obtained as follows: In the formula, V p Where is the driving voltage of the first upper electrode or the second upper electrode, and E is the Young's modulus of the material of the first upper electrode or the second upper electrode. t denoted as , where is the thickness of the material of the first or second upper electrode, w is the width of the first or second upper electrode, and l is the length of the first or second upper electrode.

5. The high isolation, low start-up voltage series contact double-arm cantilever MEMS switch according to claim 1 or 2, characterized in that, The first driving electrode, the second driving electrode, the first CPW transmission line, the second CPW transmission line, and the third CPW transmission line are all made of copper; Both the first upper electrode and the second upper electrode are made of gold.

6. The high isolation, low start-up voltage series contact double-arm cantilever MEMS switch according to claim 1 or 2, characterized in that, The substrate is made of quartz, GaN, or GaAs.

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