[0053] Example 1
[0054] Please also refer to figure 1 and Figure 4 , the high-reliability capacitive RF MEMS switch provided by the present invention will now be described. The high-reliability capacitive RF MEMS switch includes a substrate 1, a driving part 2 arranged inside the substrate 1, a transmission part 3, and a sliding part 4 arranged on the substrate 1. The sliding part 4 is composed of The driving member 2 drives the substrate 1 to achieve plane movement. Both the driving part 2 and the transmission part 3 are arranged inside the base 1 , and the driving part 2 and the transmission part 3 are located at the same height of the base 1 . Preferably, the driving part 2 and the transmission part 3 need to be staggered in the horizontal layout, and the two cannot overlap each other, so as not to affect the driving or capacitive coupling.
[0055] The two sides of the substrate 1 are the input side 11 and the output side 12 respectively, and the other two sides are provided with a transmission ground wire 33 . Cooperate to realize the coupling output of the capacitor.
[0056] Among them, the substrate 1 is generally made of high-resistance silicon, silicon oxide, or silicon nitride. The driving component 2 and the transmission component 3 are metal conductive elements embedded in the substrate 1 or located above or below the substrate 1. The driving component 2 Connected to an external circuit, the transmission component 3 is used for conducting radio frequency signals, and forms a series capacitor with the capacitor plate 41 .
[0057] In the highly reliable capacitive RF MEMS switch provided by the present invention, compared with the prior art, the horizontal layout structure can fundamentally decouple the driving part 2 from the transmission part 3 and separate the driving part 2 and the transmission part 3 , the driving part 2 is only used to drive the movement of the sliding part 4, and through the change of the coupling capacitance between the transmission part 3 and the capacitive plate 41, the opening and closing control of the RF MEMS switch is realized, and its isolation is higher and the operating power is higher, At the same time, the wear-free superslip sliding in the plane can achieve an almost infinite operating life.
[0058] Further, as a specific embodiment of the highly reliable capacitive RF MEMS switch provided by the present invention, the transmission component 3 includes an input part 31 and an output part 32, the input part 31 is located on the input side 11, The output part 32 is located on the output side 12 , and the sliding member 4 can move between the input side 11 and the output side 12 under the driving of the driving member 2 . The driving component 2 includes a first driving component 21 and a second driving component 22, the first driving component 21 is located on the input side 11, and the second driving component 22 is located on the output side 12, that is, the first driving component The components 21 are arranged on either side or opposite sides of the input portion 31 , and the second driving components 22 are arranged on either side or opposite sides of the output portion 32 .
[0059] Preferably, the length of the input part 31 is greater than the length of the first drive assembly 21, and one end of the first drive assembly 21 close to the output part 32 is flush with the input part 31 or protrudes from the input part 31; the output The length of the portion 32 is greater than the length of the second driving assembly 22 , and one end of the second driving assembly 22 close to the input portion 31 is flush with the output portion 32 or protrudes from the output portion 32 . At this time, it can be ensured that the first drive assembly 21 and the second drive assembly 22 can cooperate to excite, so as to realize the reciprocating motion of the sliding member 4 . Of course, in other embodiments, the length of the input portion 31 may also be less than or equal to the length of the first driving assembly 21 .
[0060] Further, as a specific implementation manner of the highly reliable capacitive RF MEMS switch provided by the present invention, the first driving component 21 and the second driving component 22 each include at least two separate driving electrodes, and The driving electrodes are arranged around the input part 31 or the output part 32 , and the two driving electrodes are respectively located on both sides of the input part 31 or the two sides of the output part 32 , and can drive the sliding member 4 on the input part 31 or the output part 32 . 32's top movement.
[0061] Wherein, all the driving electrodes of the first driving assembly 21 are connected, preferably, all the driving electrodes are connected through the first connection electrode 211 , and the first connection electrode 211 can extend between the input part 31 and the output part 32 , and connect the driving electrodes on both sides of the input part 31 at the same time, the setting of the first connection electrode 211 can extend the maximum driving distance of the sliding member 4, and when necessary, the sliding member 4 can be driven not to face the input part 31, So as to achieve better isolation effect.
[0062] All the driving electrodes of the second driving component 22 are also connected to each other, and the connection between all the driving electrodes is realized through the second connection electrode 222, which cooperates with the first connection electrode 211 to achieve a better isolation effect.
[0063] Preferably, both the first connection electrode 211 and the second connection electrode 222 have a certain line width, and the first connection electrode 211 and the second connection electrode 222 cooperate with other driving electrodes to achieve the effect of pushing the sliding member 4 to move, Therefore, its line width needs to be larger than 0.2 μm, or the driving voltage needs to be increased.
[0064] The driving component 2 further includes a ground electrode 23, the ground electrode 23 is located between the first driving component 21 and the second driving component 22, and the ground electrode 23 is connected to the first driving component 21 or the second driving component 22. The two sides of the sliding member 4 are connected with each other, so as to realize the bias on both sides of the sliding member 4 , and then drive the movement of the sliding member 4 .
[0065] Further, see figure 1 and Figure 4 , as a specific embodiment of the highly reliable capacitive RF MEMS switch provided by the present invention, the sliding member 4 includes a capacitive plate 41 and a sliding frame 42, and the sliding frame 42 is erected on the substrate 1 and drives When the capacitor plate 41 moves, the lower surface of the capacitor plate 41 is not in contact with the substrate 1 , which can avoid friction between the capacitor plate 41 and the substrate 1 . At least one super-sliding sheet 422 can be placed under the capacitor plate 41, so that the super-sliding sheet 422 is in contact with the substrate 1, and the capacitor plate 41 can slide on the substrate 1 with zero wear, which can realize extremely low friction and no wear. slide. At the same time, the bistable pull-in can greatly reduce the charge accumulation on the insulating layer 13, and at the same time, greatly reduce the energy consumption, and realize an ultra-long life.
[0066] Preferably, the sliding frame 42 includes at least four support blocks 421, the support blocks 421 are connected to the capacitor plate 41, and a plurality of support blocks 421 are respectively arranged at the bottom of the capacitor plate 41, and can support the entire capacitor plate after being combined 41 , so that there is a certain gap between the capacitor plate 41 and the substrate 1 to prevent the capacitor plate 41 from directly contacting the substrate 1 . Preferably, the support blocks 421 are respectively disposed at four sides or corners of the capacitor plate 41 .
[0067] Further, see figure 1 and Figure 5 , a sliding groove 14 is opened on the base 1, and the support block 421 is located in the sliding groove 14 and slides in the sliding groove 14. At this time, the bottom surface of the sliding groove 14 is an atomic level flat surface, and the supporting block The super sliding sheet 422 at the bottom of 421 is in super sliding contact with the bottom surface of the sliding groove 14 , and restricts the moving direction of the sliding member 4 through electrostatic energy, so as to prevent the sliding member 4 from deflecting.
[0068] Preferably, the sliding slot 14 provided on the substrate 1 is generally provided inside the transmission ground wire 33, which can avoid capacitive coupling between the transmission ground wire 22 and the capacitor plate 41, thereby affecting the switch insertion loss.
[0069] Preferably, the capacitor plate 41 is made of metal material, and the metal material can be made of aluminum, copper, nickel or other alloys with good electrical conductivity and lighter weight; the capacitor plate 41 can also be directly made of a whole piece of lightweight graphite sheet or other material of lightweight semiconducting material made of super-sliding sheet. The thickness of the capacitor plate 41 is 0.1 μm to 50 μm, and the gap between the capacitor plate 41 and the substrate 1 is 0.05 μm to 8 μm.
[0070] Further, see figure 1 , Figure 4 and Figure 5, as a specific embodiment of the high-reliability capacitive RF MEMS switch provided by the present invention, an insulating layer 13 is further provided on the substrate 1, and the insulating layer 13 is located between the driving part 2 and the transmission part 3, the disposition of the insulating layer 13 can avoid the direct contact between the driving part 2 and the transmission part 3 and the capacitor plate 41. Preferably, the insulating layer 13 is only coated directly above the driving part 2 and the transmission part 3, and the insulating layer 13 is not provided inside the sliding groove 14, and the inner surface of the sliding groove 14 is an atomically flat surface; The interior of 14 is also filled with an insulating layer 13, and the insulating layer 13 in this region satisfies the atomic level flatness.
[0071] In this case, the sliding groove 14 may not be provided, and the super sliding sheet 422 at the bottom of the support block 421 is in direct super sliding contact with the insulating layer 13 . Preferably, the thickness of the insulating layer 13 is 10 nm to 80 nm, and the thickness of the insulating layer 13 is relatively thin, which can prevent the gap between the transmission component 3 and the capacitor plate 41 from being too large, thereby weakening the driving force and affecting its reaction speed.
[0072] In other embodiments of the present invention, the sliding part 4 of the capacitive RF MEMS switch may also include only a capacitive plate 41 , the lower surface of the capacitive plate 41 has a super-smooth surface, and the upper surface of the substrate 1 is an atomically flat surface. In this case, the capacitor plate 41 is directly disposed on the substrate 1, and the capacitor plate 41 and the substrate 1 are in super-slid contact and slide, and the sliding frame 42 does not need to be provided.
[0073] Preferably, when the sliding frame 42 is not provided, the size of the capacitor plate 41 is generally in the order of micrometers. Of course, the size of the capacitor plate 41 can also be in the order of millimeters or centimeters according to actual conditions and specific needs. An insulating layer 13 is provided on the upper surface of the substrate 1 . The insulating layer 13 can prevent the contact between the transmission part 3 and the capacitor plate 41 and can form a capacitance gap between the transmission part 3 and the capacitor plate 41 .
[0074] For RF switches, isolation and insertion loss are the two most important indicators to determine RF switches, while the up-state capacitance (C up ) and capacitance ratio (C down /C up ) is the main restriction factor affecting the above characteristics, the capacitance between the input part 31 and the capacitor plate 41 is C 1 , the capacitance between the output part 32 and the capacitor plate 41 is C 2; For capacitive RF MEMS switches, which require disconnection, C p approaching 0, C when turned on p is the number of picofarads;
[0075] Capacitor C 1 for:
[0076] Capacitor C 2 for:
[0077] Total drive system capacitance C p for:
[0078] Total electrostatic energy of the drive system:
[0079] Horizontal driving force F x :
[0080]
[0081] where ε 0 is the vacuum dielectric constant;
[0082] ε r is the relative permittivity of the dielectric layer;
[0083] g is the thickness of the insulating layer 13;
[0084] x is displacement;
[0085] W a is the width of the ground electrode 23;
[0086] W b is the width of the drive electrode;
[0087] a is the length of the ground electrode 23;
[0088] V is the driving voltage.
[0089] It can be seen from the formula that the horizontal driving force gradually decreases with the displacement x, and decreases in a quadratic speed. When x=0, that is, the initial position, the horizontal driving force has a maximum value , while the initial maximum is determined by the air gap g and the drive electrode length W b and the driving voltage V is determined. That is, the smaller the air gap g, the wider the drive electrode width W. b The larger, the greater the initial driving force.
[0090] in, , under the design size, the upper-state capacitance simulation diagram is as follows Figure 8 As shown, the insertion loss graph is as Figure 9 As shown, the isolation diagram is shown in Figure 10 As shown, this high-reliability capacitive RF MEMS switch has excellent RF characteristics, with a minimum up-state capacitance of 2.5fF and a down-state/up-state capacitance ratio as high as 235, which is different from the traditional vertical drive structure. The sliding of 4 realizes signal switching. When DC bias is applied between the ground electrode 23 and the driving electrode, the sliding part 4 slides to coincide with the transmission part 3 under the action of the horizontal electrostatic force, thereby controlling the coupling between the sliding part 4 and the transmission part 3 The change of capacitance realizes the on-off of the radio frequency signal. Since there is no suspended structure, and there is no wear, low friction, and no impact sliding between the sliding part 4 and the insulating layer 13 during the switching process, impact damage can be completely avoided, and the bistable driving mode can greatly reduce the charge of the insulating layer. Accumulate, significantly improve the operating life of RF MEMS switches.
[0091] As an alternative embodiment of the present invention, in other embodiments of the present invention, the driving part 2 and the transmission part 3 are located at different heights of the substrate 1, and the transmission part 3 is located above the driving part 2, and the driving part 2 and the transmission part 3 Staggered settings on a horizontal layout with no or minimal staggering.
[0092] As an alternative embodiment of the present invention, in other embodiments of the present invention, please refer to Image 6 It is also possible not to provide a separate sliding groove 14, and the bottom of the support block 421 can directly abut with the upper surface of the substrate 1 or the upper surface of the insulating layer 13. At this time, the upper surface of the substrate 1 is an atomically flat surface, and the bottom of the support block 421 The super-slip sheet 422 is in super-slip contact with the substrate 1.
[0093] As an alternative embodiment of the present invention, in other embodiments of the present invention, please refer to Image 6 , the insulating layer 13 may not be provided, the driving component 2 and the transmission component 3 are embedded in the interior of the substrate 1 or below the substrate 1, the upper surface of the entire substrate 1 satisfies the atomic level flatness, and the sliding component 4 is directly on the substrate. 1 surface sliding.
[0094] As an alternative embodiment of the present invention, in other embodiments of the present invention, please refer to Figure 7 , the sliding part 4 of the capacitive RFMEMS switch can also only include a capacitor plate 41, the lower surface of the capacitor plate 41 has a super-smooth surface, and the upper surface of the substrate 1 is an atomically flat surface, and the capacitor plate 41 is directly arranged on the substrate 1. Or on the insulating layer 13, and the capacitor plate 41 and the substrate 1 or the insulating layer 13 are in super-slip contact and slide, and the sliding frame 42 does not need to be provided.
[0095] Preferably, the size of the capacitor plate 41 is generally in the order of micrometers. Of course, the size of the capacitor plate 41 may also be in the order of millimeters or centimeters according to actual conditions and specific requirements. An insulating layer 13 is provided on the upper surface of the substrate 1 . The insulating layer 13 can prevent the contact between the transmission part 3 and the capacitor plate 41 and can form a capacitance gap between the transmission part 3 and the capacitor plate 41 .
