Coaxial variable capacitor

Abstract

The variable capacitor includes first and second movable capacitor plate assemblies disposed inside the housing and including first and second movable capacitor plates. A first fixed capacitor plate and a second fixed capacitor plate are disposed proximal to the first and second movable capacitor plates, respectively. The plurality of capacitor plates may comprise concentric cylindrical blades that are variably interengaged, and the first movable capacitor plate and the first fixed capacitor plate may be coaxial with the second movable capacitor plate and the second fixed capacitor plate. A plurality of actuators may be provided to move the first and second movable capacitor plate assemblies forward and backward independently relative to the first and second fixed capacitor plate assemblies, changing the capacitance of the variable capacitor by independently adjusting the amount of interengagement of the capacitor plates of each pair of capacitor plate assemblies.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the priority of U.S. Utility Patent Application No. 17 / 879,317, filed on August 2, 2022, the content of which is incorporated herein by reference.

[0002] This application is related to U.S. Patent Application No. 17 / 739,595, entitled "DIELECTRIC FLUID VARIABLE CAPACITOR", filed previously in the names of Tigran Poghosyan, Anthony Oliveti, Gabe Calebotta, and Kirkwood Rough, the content of which is incorporated herein by reference.

[0003] This application is also related to U.S. Patent Application No. 17 / 739,745, entitled "VARIABLE CAPACITOR WITH LINEAR IMPEDANCE AND HIGH VOLTAGE BREAKDOWN", filed previously in the names of Tigran Poghosyan and Anthony Oliveti, the content of which is incorporated herein by reference.

Background Art

[0004] Variable capacitors are used in various applications, especially those dealing with high - frequency and high - power signals. Variable capacitors are utilized, for example, in oscillator circuits for high - power wireless transmission, high - frequency power supplies for semiconductor manufacturing equipment, impedance - matching networks that match the impedance of a time - dependent high - frequency load and a generator, and the like.

[0005] A capacitor basically consists of an insulator or dielectric material disposed between capacitor plates and at least two capacitor plates spaced apart. As used herein, the terms "dielectric", "dielectric material", and "dielectric medium" are used interchangeably to refer to a material (i.e., solid, liquid, or gas) that is polarizable in the presence of an electric field and is typically represented by the electric susceptibility χ of the material.

[0006] In a vacuum variable capacitor, at least two capacitor plates are maintained in a high vacuum (e.g., 10 -6 Torr (133.322 μPa) or less) that functions as the dielectric of the capacitor, and its susceptibility is approximately zero. In some vacuum variable capacitors, the capacitor plates can be configured as a plurality of mutually engaging concentric plates, and the variability of the capacitance can be achieved by physically adjusting the length of the overlap in the mutual engagement.

[0007] In a liquid dielectric variable capacitor as disclosed in the above-mentioned '595 application, a liquid dielectric is provided between the capacitor plates and functions as a dielectric. The liquid dielectric can improve the thermal performance and capacitance performance of the variable capacitor.

[0008] This disclosure is best understood from the following detailed description when read in conjunction with the accompanying drawings.

Brief Description of the Drawings

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Figure 1

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Figure 2

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Figures 3A - 3D

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Figure 4

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Figure 5

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Figure 6

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Figure 7

[0016] It is emphasized that various features are not drawn to scale in accordance with standard industry practice. In fact, the dimensions of various features may be arbitrarily enlarged or reduced for clarity of discussion and illustration.

[0017] DETAILED DESCRIPTION Exemplifications of the subject matter claimed below are disclosed. For clarity, not all features of the actual implementation for each example are described. It will be understood that in the development of such actual implementations, numerous implementation-specific decisions may be made for each implementation to achieve the developer's specific goals, such as compliance with system-related and business-related constraints. Further, it will be understood that such development efforts, even if complex and time-consuming, are routine for those skilled in the art having the advantages of this disclosure.

[0018] Expressions such as "include" and "may include" that may be used in the present disclosure indicate the presence of the disclosed functions, operations, and components, and do not limit the presence of one or more additional functions, operations, and components. In the present disclosure, terms such as "include" and / or "have" may be interpreted as indicating a specific characteristic, number, operation, component, element, or a combination thereof, but should not be interpreted as excluding the presence or possibility of addition of one or more other characteristics, numbers, operations, components, elements, or a combination thereof.

[0019] As used herein, the article "a" is intended to have its ordinary meaning in the patent art, i.e., "one or more". In this specification, when applied to a value, the term "about" generally means within the tolerance of the equipment used to generate the value, and in some examples, plus or minus 10%, or plus or minus 5%, or plus or minus 1% unless explicitly specified otherwise. Further, the term "substantially" as used herein means a majority, or almost all, or all, or an amount in the range of, for example, about 51% to about 100%. Further, the examples in this specification are intended for illustration only and are presented for discussion and not for limitation.

[0020] As used herein, "providing" an article means owning and / or managing that article. This includes, for example, forming (or assembling) part or all of the article from constituent materials and / or owning and / or managing an already formed article.

[0021] As used herein, "coaxial" refers to the relationship between two structures having coincident axes, such as a first cylindrical structure surrounding a second cylindrical structure, each having the same axis.

[0022] Unless otherwise defined, all terms including technical and / or scientific terms used herein shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. In addition, unless otherwise defined, all terms defined in commonly used dictionaries shall not be interpreted overly.

[0023] The subject matter described herein is directed to examples of coaxial variable capacitors, as well as examples of coaxial variable capacitors incorporating a liquid dielectric material between capacitor plates. In the latter examples, the liquid dielectric material can increase the effective maximum capacitance of the variable capacitor for a given capacitor plate shape. The liquid dielectric material can further increase the electrical breakdown voltage of the capacitor for a given capacitor plate shape. The liquid dielectric material may further provide additional dissipation of thermal energy within the variable capacitor, for example compared to a coaxial capacitor, due to the possibility of a liquid dielectric having a higher thermal conductivity than vacuum.

[0024] FIG. 1 is an external isometric view of a coaxial variable capacitor 100 according to one or more examples. The coaxial variable capacitor 100 includes a housing 102 having an actuator end cap 104, as described below. In the example of FIG. 1, the housing 102 includes a top conductive collar 106 and a bottom contact assembly 108 that are electrically insulated from each other by an intermediate cylindrical insulator 110 that is hermetically joined to the top conductive collar 106 and the bottom contact assembly 108. In the example, the conductive collars 106 and 108 may be metals such as silver-plated copper, copper, brass, aluminum, or brazed aluminum. In the example, the intermediate electrical insulating element 110 is substantially cylindrical and may be made of ceramic or other suitable insulating material. A threaded actuator 115 may surround the actuator end cap 104.

[0025] The upper end of the actuator 114 extends from the actuator end cap 104. In some examples, the actuator 114 is threaded and can be rotated within the housing 102 to advance and retract the movable capacitor assembly 124 relative to the fixed capacitor assembly 130, as described below. In other examples, the actuator 114 can be advanced and retracted by a linear motor, an electromagnetic coil device, or a hydraulic or pneumatic system. Similarly, the threaded actuator 115 can be actuated to advance and retract the movable capacitor assembly 122 relative to the fixed capacitor assembly 128 within the housing 102, as described below.

[0026] FIG. 2 is a cutaway isometric view of a coaxial variable capacitor 100 according to one or more examples. FIGS. 3 and 4 are front cross-sectional views of a coaxial variable capacitor 100 having a movable capacitor plate assembly 118 and a fixed capacitor plate assembly 120 housed within the housing 102. The movable capacitor plate assembly 118 includes a first movable capacitor plate assembly 122 and a second movable capacitor plate assembly 124. The fixed capacitor plate assembly 120 includes a third capacitor plate assembly 128 and a fourth capacitor plate assembly 130. As described herein, in some examples, the first movable capacitor plate assembly 122 can move independently of the second movable capacitor plate assembly 124. The bottom surface 129 of the third capacitor plate assembly 128 of the fixed capacitor plate assembly 120 defines an annular conductive contact outside the contact assembly 108. The bottom surface 131 of the fourth capacitor plate assembly 130 defines an annular conductive contact inside the contact assembly 108.

[0027] Figure 4 is a cutaway exploded isometric view of the capacitor plate assemblies 122, 124, 128, and 130 separated. In the example, the capacitor plate assemblies 122, 124, 128, and 130 each include a plurality of concentric cylindrical blades 132, 134, 136, and 138, and the respective cylindrical blades 132 and 136 of the capacitor plate assemblies 122 and 128 are inter-fitted, and the respective cylindrical blades 134 and 138 of the capacitor plate assemblies 124 and 128 are maintained in a coaxial orientation within the housing 102 such that they can be inter-fitted. Figure 6 is an enlarged cutaway exploded isometric view of the capacitor plate assemblies 122 and 128 and the respective blades 132 and 138.

[0028] As shown in Figure 2, the fixed capacitor plate assembly 128 further includes an insulating ring 140 that separates the capacitor plate assemblies 128 and 130 and electrically insulates them. In the example, the insulating ring 140 may be made of ceramic or other suitable insulating material.

[0029] In some embodiments (not depicted in the drawings of this specification), the height of one or more of the capacitor plate assemblies 122, 124, 126, 128 may vary, such as from the maximum height at the central portion of the capacitor plate coil to the minimum height at the outer portion of the capacitor plate coil. (As used in this specification, the term "height" when describing a capacitor plate refers to the dimension of the capacitor plate extending in a direction away from the respective mounting plate). By providing capacitor plates of various heights, it is possible to make the curve showing the relationship between the capacitance and the position of a pair of capacitor plates approximate a power function more closely rather than a linear function, while making the curve showing the relationship between the impedance and the position approximate a linear function more closely rather than a power function. This concept is described in more detail in the above-mentioned Application No. 745.

[0030] In the example, the first and second capacitor plate assemblies 118 and 120 are configured such that the first capacitor plate assembly 122 is at least partially concentrically interengaged with the third capacitor plate assembly 128, and the second capacitor plate assembly 124 is at least partially concentrically interengaged with the fourth capacitor plate assembly 130. In the example, the first capacitor plate assembly 122 and the third capacitor plate assembly 128 do not contact each other directly, and the second capacitor plate assembly 124 does not contact the fourth capacitor plate assembly 130 directly.

[0031] The spacing between the first capacitor plate assembly 122 and the third capacitor plate assembly 128, and the spacing between the second capacitor plate assembly 124 and the fourth capacitor plate assembly 130 may be adjusted as described herein to vary the length of the concentric and overlapping interengagement between the first capacitor plate 118 and the third capacitor plate assembly 128, and between the second capacitor plate assembly 124 and the fourth capacitor plate assembly 130. As described above, the variation in the spacing between the first capacitor plate assembly 122 and the third capacitor plate assembly 128 may be adjusted independently of the spacing between the second capacitor plate assembly 124 and the fourth capacitor plate assembly 130. That is, the first capacitor plate assembly 122 can be raised and lowered relative to the third capacitor plate assembly 128 independently of the raising and lowering of the second capacitor plate assembly 124 relative to the fourth capacitor plate assembly 130. This variation in the interengagement of the pair 122 / 128 of capacitor plate assemblies, and / or the pair 124 / 130, thereby enables adjustment of the effective capacitance of the sets 122 / 128 and 124 / 130 of those capacitor plate assemblies. In the example, the capacitor plate assemblies 122, 124, 128, and 130 may be made of materials (e.g., oxygen-free copper or copper-plated brass) conventionally used in such structures in variable capacitors.

[0032] Figures 3A, 3B, 3C, and 3D are isometric cross-sectional views of a coaxial variable capacitor 100 according to one or more examples in which capacitor plate assemblies 122, 124, 128, and 130 are in various relative positions. In particular, FIG. 3A shows that the first (movable) capacitor plate assembly 122 is lifted to the maximum distance from the third (stationary) capacitor plate assembly 128, providing a minimum capacitance between capacitor plate assemblies 122 and 128m, and the second (movable) capacitor plate assembly 124 is lifted to the maximum distance from the fourth (stationary) capacitor plate assembly 130, providing a minimum capacitance between capacitor plate assemblies 124 and 130.

[0033] FIG. 3B shows that the first (movable) capacitor plate assembly 122 is lowered so as to be at the shortest distance from the third (stationary) capacitor plate assembly 128, providing a maximum capacitance between capacitor plate assemblies 122 and 128, and the second (movable) capacitor plate assembly 124 is lowered so as to be at the shortest distance from the fourth (stationary) capacitor plate assembly 130, providing a maximum capacitance between capacitor plate assemblies 124 and 130.

[0034] FIG. 3C shows that the first (movable) capacitor plate assembly 122 is lifted to the maximum distance from the third (stationary) capacitor plate assembly 128, providing a minimum capacitance therebetween, and the second (movable) capacitor plate assembly 124 is lowered to the minimum distance from the fourth (stationary) capacitor plate assembly 130, providing a maximum capacitance therebetween.

[0035] FIG. 3D shows that the first (movable) capacitor plate assembly 122 is lowered to a minimum distance from the third (stationary) capacitor plate assembly 128, providing a maximum capacitance therebetween, and the second (movable) capacitor plate assembly 124 is raised to a maximum distance from the fourth (stationary) capacitor plate assembly 130, providing a minimum capacitance therebetween.

[0036] In various examples, the spacing between each pair of capacitor plate assemblies 122 / 128 and the spacing between pair 124 / 130 can be independently adjusted to any intermediate distance between the extreme positions illustrated in FIGS. 3A - 3D, enabling an adjustable range of capacitance between pairs of capacitor plate assemblies 122 / 128 and between pairs 124 / 130.

[0037] Continuing to refer to FIGS. 2 and 3A - 3D, and particularly to FIGS. 3A - 3D, in one or more examples, a plurality of flexible structures 142, 144, and 146 are in a hermetic attachment state with the top conductive collar 106 and various capacitor plate assemblies 122, 124 as described herein. In various examples such as those depicted in FIGS. 2 - 4, the flexible structures 142, 144, and 146 comprise a compressible bellows structure. In various examples, the flexible structures 142, 144, and 146 can be made of a conductive material to provide an electrical conduction path between the capacitor plate assemblies 122 and 124 and the top conductive collar 106.

[0038] In the example of FIGS. 2 and 3A - 3D, the flexible structure 142 has one end coupled to the first mounting annular portion 148 below the top conductive collar 106 and the opposite end coupled to the upper surface 150 of the capacitor plate assembly 122. The flexible structure 144 is coaxial and concentric with the flexible structure 142, has one end coupled to the second mounting annular portion 152 below the top conductive collar 106, and the opposite end coupled to a cylindrical piston structure 154 that is coupled to the threaded actuator 115. The flexible structure 146 is coaxial and concentric with the flexible structures 142 and 144, has one end coupled to the third mounting annular portion 156, and the opposite end coupled to the upper surface 158 of the second capacitor plate assembly 124. FIG. 7 is an exploded isometric view of the coaxial flexible structures 142, 144, and 146 according to one or more examples.

[0039] As shown in FIGS. 3A - 3D, the actuator 114 passes through one or more bearings or gaskets 160 within the actuator end cap 104, extends through the opening of the conductive collar 106, and extends partially within the flexible structure 146. In one or more examples, the actuator 114 engages the thrust collar 154 in a threaded manner.

[0040] Continuing to refer to FIGS. 2, 3A - 3D, and 4, the sealed volume 166 is defined within the housing 102. Referring particularly to FIGS. 3 and 4, (multiple reference numerals 166 appear in FIGS. 3A - 3D to indicate the extent of the sealed volume 166).

[0041] In an example, due to a seal, which may be formal, between the actuator 114 and the bearing or gasket 160, where the actuator 114 enters the actuator end cap 104, a region within the housing 102 may be at, or near, external atmospheric pressure. On the other hand, the flexible structures 142, 144, and 146 are sealed and attached to the top conductive collar 106 and, as described above, to the first capacitor plate assembly 122, the piston structure 154, and the second capacitor plate assembly 124, such that the sealed volume 166 is hermetically (i.e., vacuum and liquid tight) sealed.

[0042] According to this example, the degree of inter-fitting overlap between the first capacitor plate assembly 122 and the third capacitor plate assembly 128, and thus the effective capacitance of the pair of capacitor plate assemblies 122 and 128, can be adjusted by rotation of the actuator 114. Similarly, the degree of inter-fitting overlap between the second capacitor plate assembly 124 and the fourth capacitor plate assembly 130, and thus the effective capacitance of the pair of capacitor plate assemblies 124 and 130, can be adjusted by rotation of the threaded actuator 115. Rotation of the actuator 114 by, for example, a stepping motor or a servo motor (not shown) causes the threads of the actuator 114 to raise or lower the thrust collar 162 and the extension coupling 164, thereby raising or lowering the movable capacitor plate assembly 118 relative to the fixed capacitor plate assembly 120. Rotation of the threaded actuator 115 by, for example, a belt or a stepping motor raises or lowers the threaded actuator 155.

[0043] In the example, the flexible structures 142, 144, and 146, the extension coupling 164, the thrust collar 162, and the piston structure 154 are conductive (e.g., made of metal) and provide a low-resistance electrical conduction path between the first capacitor plate assembly 122, the second capacitor plate assembly 124, the top conductive collar 106, and the threaded actuator 115. As described above, the bottom surface 129 of the third capacitor plate assembly 128 functions as another contact of the coaxial variable capacitor 100, and the bottom surface 131 of the fourth capacitor plate assembly 130 functions as another contact of the coaxial variable capacitor 100.

[0044] In various examples, the coaxial variable capacitors described herein can achieve high power density, current handling capability, and high voltage handling capability within a small volume. By having pairs of a plurality (two or more) of capacitor plates, such as the interlocking cylindrical blades described herein, the high current handling capability is maintained along with the high breakdown voltage of the variable capacitor without additional volume being occupied by the dielectric of the vacuum mechanism. Due to the coaxial symmetry, the volume efficiency is maximized, enabling all electrode assemblies to be sealed (e.g., brazed) into one structure. In some examples, the brazing of the internal components can be performed in one step.

[0045] One or more variable vacuum capacitors, such as the variable vacuum capacitors in the examples of FIGS. 1-7 herein, can be used for tuning the matching network and other controls in a radio frequency plasma processing device. RF plasma-enhanced processing is widely used in semiconductor manufacturing to etch various types of films, deposit thin films at low to intermediate processing temperatures, and perform surface treatment and cleaning. One feature of such processes is the use of a plasma, i.e., a partially ionized gas, to generate neutral species and ions from precursors within the reaction chamber, supply energy for ion bombardment, and / or perform other operations. Radio frequency plasma-enhanced processing is carried out by what is known as a radio frequency processing device.

[0046] A radio frequency processing device can include a radio frequency generator that transmits signals to a plasma reaction chamber. A radio frequency matching device having a variable impedance can be disposed between the radio frequency generator and the plasma reaction chamber. The radio frequency matching device is controlled by varying the impedance of the radio frequency matching device or is adjusted in other ways. By adjusting the radio frequency matching device, the reflected power from the plasma reaction chamber and / or the radio frequency matching device can be reduced, thereby increasing the power transmitted from the radio frequency generator to the plasma reaction chamber and the plasma process. During operation, the radio frequency generator can be energized to form a plasma within the reaction chamber. The plasma is generated after a source gas is injected into the reaction chamber and power is supplied to the reaction chamber by the high frequency generator.

[0047] Under certain conditions, the power supplied to the reaction chamber may be reflected from the reaction chamber. One cause of the reflected power may be the mismatch between the characteristic impedance of the system and the load formed by the plasma in the reaction chamber. To prevent the reflected power, a matching network can be placed between the radio frequency generator and the reaction chamber. Such a matching network can include a number of variable capacitors or other impedance elements. The variable capacitor can be adjusted so that the complex load impedance in the reaction chamber matches the impedance of the high-frequency generator.

[0048] Multiple methods for controlling or otherwise adjusting the matching network have been used, but such methods may not reliably and efficiently achieve impedance matching. The matching network may include a stepping motor having a specific number of steps that is a function specific to a particular stepping motor. During operation, the capacitor may be driven by a motor having a range between zero and 100 percent, and the motor may consequently have multiple clicks. Embodiments of the present disclosure can provide a recipe and / or enable the position of the capacitor to be adjusted in other ways, at least partially based on a "step-to-percent ratio."

[0049] Turning to FIG. 8, a schematic diagram of a matching network including one or more example variable capacitors (which may include the variable capacitor 100 described above) is shown. In the example of FIG. 8, a matching network 800 having a matching branch 802 and a splitter branch 804 is illustrated. The matching branch 802 receives radio frequency power from a radio frequency (RF) input 806. A first variable capacitor 808 of the matching branch 802 receives RF power from the RF input 806. The first variable capacitor 808 may be a variable capacitor as disclosed herein with reference to FIGS. 1-7 and may have a rating of about 10 to 2000 pF.

[0050] In the example of FIG. 8, the first variable capacitor 808 is connected to the second capacitor 810, which is grounded. The second capacitor 810 is also connected to the third variable capacitor 812. The third variable capacitor 812 may also be a variable capacitor as disclosed herein with reference to FIGS. 1-7 and may have a rating of about 10-2000 pF. The third variable capacitor 812 is also connected to an inductor 814, which is further connected to a splitter branch 804.

[0051] The splitter branch 804 receives RF power from the matching branch 802, which splits the received RF power between a fourth variable capacitor 816 and a fifth variable capacitor 818. The fourth variable capacitor 816 and the fifth variable capacitor 818 may also be variable capacitors as disclosed herein with reference to FIGS. 1-7 and may have a rating of about 10-2000 pF.

[0052] The fifth variable capacitor 818 is connected to an inner coil 820. One or more sensors 822 may be disposed between the fifth variable capacitor 818 and the inner coil 820. The sensor 822 may be used, for example, to measure the voltage between the fifth variable capacitor 818 and ground. Similarly, the fourth variable capacitor 816 is connected to an outer coil 824. One or more sensors 826 may be disposed between the fourth variable capacitor 816 and the outer coil 824. The sensor 826 may be used, for example, to measure the voltage between the fourth variable capacitor 816 and ground.

[0053] The inner coil 820 may be further connected to ground, and the outer coil 824 may be connected to a circuit network including a sensor 828 and a sixth capacitor 830. The sensor 828 may be used, for example, to measure the voltage between the outer coil 824 and ground. The inner coil 820 and the outer coil 824 may be disposed outside the matching network 800 circuit network as shown by the dashed line 832 in FIG. 8.

[0054] The circuit network shown in FIG. 8 can be used to adjust the first variable capacitor 808, the third variable capacitor 812, the fourth variable capacitor 816, and the fifth variable capacitor 818. By adjusting the first variable capacitor 808, the third variable capacitor 812, the fourth variable capacitor 816, and the fifth variable capacitor 818, the power supplied to the inner coil 820 and the outer coil 824 can be adjusted.

[0055] In one embodiment, the circuit network that can be employed in the matching network 800 as a current division ratio matching network can be controlled using a programmable logic controller (not shown) that is disposed within the matching network 800 or otherwise connected to the matching network 800.

[0056] In the foregoing description, for purposes of explanation, specific terminology has been used to provide a thorough understanding of the present disclosure. However, it will be apparent to those skilled in the art that specific details are not required in order to practice the systems and methods described herein. The foregoing description of specific examples is presented for purposes of illustration and explanation. The examples herein are not intended to be exhaustive or to limit the present disclosure to the precise form described. Many modifications and variations are possible in light of the above teachings.

[0057] For example, although implementations incorporating two pairs of coaxial capacitor plates are described herein, it is contemplated that in other embodiments, more than three pairs of coaxial plates may be incorporated. Further, although the examples described herein include two or more movable coaxial plates that move simultaneously with respect to two or more fixed coaxial plates, it is contemplated that in other embodiments, one or more of the coaxial plates may move forward or backward independently of the others.

[0058] The examples in this specification are presented and described in order to best explain the principles and practical applications of the present disclosure, so that those skilled in the art can make various changes while best utilizing the present disclosure and various embodiments to suit the specific intended uses. It is intended that the scope of the present disclosure be defined by the following claims and their equivalents.

Claims

1. It is a variable capacitor, A housing having an interior, a top conductive collar, and a bottom contact assembly electrically isolated by a cylindrical insulator; Displaced inside the housing is a first movable capacitor plate assembly, which includes a first capacitor plate; Displaced inside the housing, a second movable capacitor plate assembly including a second capacitor plate; A first flexible structure having a first end sealed to the top conductive collar and a second end sealed to the first movable capacitor plate assembly; A second flexible structure coaxial with the first flexible structure and surrounding the first flexible structure, the second flexible structure having a first end sealed to the top conductive collar and a second end sealed to the second movable capacitor plate assembly; A third flexible structure that is coaxial with the first flexible structure and the second flexible structure, and surrounds the first flexible structure and the second flexible structure, having a first end sealed to the top conductive collar and a second end sealed to the second movable capacitor plate assembly; A first fixed capacitor plate assembly, positioned proximal to the first movable capacitor plate assembly and including a third capacitor plate; A second fixed capacitor plate assembly, positioned proximal to the second movable capacitor plate assembly and including a fourth capacitor plate; A first actuator extending through the top conductive collar and the first flexible structure, the distal end of which the first actuator engages with a thrust collar, and the first actuator is for moving the first movable capacitor plate assembly forward and backward relative to the first fixed capacitor plate assembly; A second actuator extending through the top conductive collar and coupled to a piston structure, for the purpose of moving the piston structure forward and backward, and moving the second movable capacitor plate assembly forward and backward relative to the second fixed capacitor plate assembly; Equipped with, The first capacitor plate and the third capacitor plate each comprise a plurality of concentric cylindrical plates that are fitted together, and the second capacitor plate and the fourth capacitor plate each comprise a plurality of concentric cylindrical plates that are fitted together. Variable capacitor.

2. The variable capacitor according to claim 1, wherein the first actuator includes a thread for engaging with the thrust collar, so that rotation of the first actuator in a first direction advances the first movable capacitor plate assembly toward the first fixed capacitor plate assembly, expanding the first flexible structure, and rotation of the first actuator in a second direction retracts the first movable capacitor plate assembly toward the first fixed capacitor plate assembly, contracting the first flexible structure.

3. The variable capacitor according to claim 2, wherein when the second actuator moves forward into the housing, the second movable capacitor plate assembly moves forward toward the second fixed capacitor plate assembly, and the second flexible structure and the third flexible structure expand, and when the second actuator moves backward outward from the housing, the second movable capacitor plate assembly moves backward toward the second fixed capacitor plate assembly, and the second flexible structure and the third flexible structure contract.

4. The variable capacitor according to claim 1, wherein the first flexible structure, the second flexible structure, and the third flexible structure each comprise a bellows structure.

5. The variable capacitor according to claim 1, wherein the first capacitor plate, the second capacitor plate, the third capacitor plate, and the fourth capacitor plate each comprise a plurality of concentric cylindrical plates having a certain height.

6. The capacitor according to claim 1, wherein at least the first capacitor plate and the second capacitor plate each include a cylindrical coil having a higher height in its central portion and a lower height in its outer portion.

7. The variable capacitor according to claim 1, wherein the first capacitor plate, the second capacitor plate, the third capacitor plate, and the fourth capacitor plate each comprise a plurality of foldable concentric plates, each having a conical cross-section, the vertices of which interlock to different degrees as the movable capacitor plate assembly moves forward and backward.

8. The forward and backward movement of the first movable capacitor plate assembly changes the degree of overlapping mating between the first capacitor plate and the third capacitor plate. The variable capacitor according to claim 5, wherein the forward and backward movement of the second movable capacitor plate assembly changes the degree of overlapping mating between the second capacitor plate and the fourth capacitor plate.

9. A bottom contact assembly including an outer conductive ring, an inner conductive ring, and an insulating ring separating the outer conductive ring and the inner conductive ring; An intermediate electrical insulating element separating the first conductive collar from the bottom contact assembly; Equipped with, The variable capacitor according to claim 3, wherein the inner conductive ring is in electrical contact with the third capacitor plate, and the outer conductive ring is in electrical contact with the fourth capacitor plate.

10. The variable capacitor according to claim 9, wherein the first flexible structure, the second flexible structure, and the third flexible structure provide a conductive connection between the movable capacitor plate assembly and the first conductive collar.

11. The variable capacitor according to claim 1, wherein a vacuum is maintained inside the housing.

12. The variable capacitor according to claim 1, wherein a liquid dielectric is housed inside the housing.

13. A method for adjusting the capacitance of a variable capacitor, To provide a housing having an interior, a top conductive collar, and a bottom contact assembly electrically isolated by a cylindrical insulator; To provide a first movable capacitor plate assembly, which is disposed inside the housing and includes a first capacitor plate; To provide a second movable capacitor plate assembly, which is disposed inside the housing and includes a second capacitor plate; To provide a first flexible structure having a first end sealed to the top conductive collar and a second end sealed to the first movable capacitor plate assembly; To provide a second flexible structure that is coaxial with the first flexible structure and surrounds the first flexible structure, having a first end sealed to the top conductive collar and a second end sealed to the second movable capacitor plate assembly; To provide a third flexible structure that is coaxial with the first and second flexible structures and surrounds the first and second flexible structures, having a first end sealed to the top conductive collar and a second end sealed to the second movable capacitor plate assembly; To provide a first fixed capacitor plate assembly, positioned proximal to the first movable capacitor plate assembly and including a third capacitor plate; To provide a second fixed capacitor plate assembly located proximal to the second movable capacitor plate assembly and including a fourth capacitor plate; To provide a first actuator, the first actuator extending through the top conductive collar and the first flexible structure, wherein the distal end of the actuator engages with a thrust collar, and the first actuator is for moving the first movable capacitor plate assembly forward and backward relative to the fixed capacitor plate assembly; To provide a second actuator that extends through the top conductive collar and is coupled to the second movable capacitor plate assembly via a piston structure, for moving the second movable capacitor plate assembly forward and backward; A method including, The first capacitor plate and the third capacitor plate are provided with a plurality of interlocking concentric cylindrical plates, and the second capacitor plate and the fourth capacitor plate are provided with a plurality of interlocking concentric cylindrical plates; and The first actuator is operated to adjust the capacitance between the first capacitor plate and the third capacitor plate, and the second actuator is operated to adjust the capacitance between the second capacitor plate and the fourth capacitor plate. Methods that include...

14. The method according to claim 13, wherein the first actuator includes threads for engaging with the thrust collar, so that rotation of the first actuator in a first direction advances the first movable capacitor plate assembly toward the first fixed capacitor plate assembly, thereby expanding the first flexible structure, and rotation of the first actuator in a second direction retracts the first movable capacitor plate assembly toward the first fixed capacitor plate assembly, thereby contracting the first flexible structure.

15. The method according to claim 14, wherein when the second actuator moves forward into the housing, the second movable capacitor plate assembly moves forward toward the second fixed capacitor plate assembly, and the second flexible structure and the third flexible structure expand, and when the second actuator retracts outward from the housing, the second movable capacitor plate assembly retracts toward the second fixed capacitor plate assembly, and the second flexible structure and the third flexible structure contract.

16. The method according to claim 13, wherein the first flexible structure, the second flexible structure, and the third flexible structure are bellows structures.

17. The method according to claim 13, wherein the independent forward and backward movement of the first movable capacitor plate assembly and the second movable capacitor plate assembly independently changes the degree of overlapping mating between the first movable capacitor plate assembly and the first fixed capacitor plate assembly, and between the second movable capacitor plate assembly and the second fixed capacitor plate assembly.

18. To provide a top conductive collar that electrically contacts the movable capacitor plate assembly, a contact assembly that electrically contacts the fixed capacitor plate assembly, and an intermediate electrical insulating element that separates the first conductive collar and the second conductive collar. The method according to claim 17, further comprising:

19. The method according to claim 18, wherein at least one of the first flexible structure, the second flexible structure, and the third flexible structure provides a conductive connection between the movable capacitor plate assembly and the top conductive collar.

20. To provide a liquid dielectric inside the housing The method according to claim 13, further comprising:

21. Maintaining a vacuum inside the aforementioned housing The method according to claim 13, further comprising:

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