Coaxial variable capacitor

Abstract

A variable capacitor includes a first movable capacitor plate assembly and a second movable capacitor plate assembly disposed in an interior space of a housing and including a first movable capacitor plate and a second movable capacitor plate. The first fixed capacitor plate and the second fixed capacitor plate are respectively arranged close to the first movable capacitor plate and the second movable capacitor plate. The capacitor plates may include variable interdigital concentric cylindrical blades, 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. Actuators may be provided for independently advancing and retracting the first and second movable capacitor plate assemblies with respect to the first and second fixed capacitor plate assemblies, so that the capacitor plates of the first and second movable capacitor plate assemblies can be aligned by independently adjusting the amount of finger intersection of the capacitor plates centered by each capacitor plate assembly. Therefore, the capacitance of the variable capacitor is changed.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application No. 17 / 879,317 filed on August 2, 2022, the entire contents of which are incorporated herein by reference.

[0003] This application is related to prior filed U.S. Patent Application No. 17 / 739,595, filed in the names of Tigran Poghosyan / Anthony Oliveti / Gabe Calebotta and Kirkwood Rough, entitled DIELECTRIC FLUID VARIABLE CAPACITOR, the entire contents of which are incorporated herein by reference.

[0004] This application is also related to the prior-filed U.S. patent application US17 / 739745, filed in the name of Tigran Poghosyan, Anthony Olivei, entitled VARIABLE CAPACITOR WITH LINEAR IMPEDANCE AND HIGH VOLTAGE BREAKDOWN, the entire contents of which are incorporated herein by reference. Technical Field

[0005] The present invention relates to the technical field of capacitors, and in particular to a coaxial variable capacitor. Background Art

[0006] Variable capacitors are used in a variety of applications, particularly those involving high frequency, high power signals. Variable capacitors can be used, for example, in oscillator circuits for high power radio transmissions, high frequency power supplies for semiconductor manufacturing equipment, and impedance matching networks in which the impedance of a time-dependent, high frequency load is matched to the impedance of a generator.

[0007] A capacitor is essentially composed of at least two spaced-apart capacitor plates, with an insulator or dielectric material disposed between the capacitor plates. As used herein, the terms "dielectric," "dielectric dielectric material," and "dielectric medium" are used interchangeably to refer to a material (i.e., a solid, liquid, or gas) that is polarizable in the presence of an electric field, typically expressed as the material's electrical susceptibility, χ.

[0008] In a vacuum variable capacitor, at least two capacitor plates are maintained in a high vacuum environment (e.g., 10 -6In some vacuum variable capacitors, the capacitor plates may be configured as multiple interdigitated concentric plates, and the capacitance may be varied by physically adjusting the overlap length of the interdigitated portions.

[0009] In a liquid dielectric variable capacitor as described in the above-mentioned US 17 / 739595 patent application, a liquid dielectric is provided between the capacitor plates to act as a dielectric liquid, which improves the thermal and capacitive performance of the variable capacitor. Summary of the invention

[0010] One aspect of the present invention is to provide a variable capacitor, comprising:

[0011] a housing having an interior space, a top conductive collar, and a bottom contact assembly, the bottom contact assembly being electrically separated by a cylindrical insulating member;

[0012] a first movable capacitor plate assembly disposed in the interior space of the housing, the first movable capacitor plate assembly comprising a first capacitor plate;

[0013] a second movable capacitor plate assembly disposed in the interior space of the housing, the second movable capacitor plate assembly comprising a second capacitor plate;

[0014] 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;

[0015] a second flexible structure coaxial with and surrounding 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;

[0016] a third flexible structure coaxial with and surrounding 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;

[0017] a first fixed capacitor plate assembly disposed proximate to the first movable capacitor plate assembly, the first fixed capacitor plate assembly including a third capacitor plate;

[0018] a second fixed capacitor plate assembly disposed proximate to the second movable capacitor plate assembly, the second fixed capacitor plate assembly including a fourth capacitor plate;

[0019] a first actuator extending through the top conductive collar and through the first flexible structure, the distal end of the first actuator engaging the thrust collar, the first actuator being used to advance and retract the first movable capacitor plate assembly relative to the first fixed capacitor plate assembly;

[0020] a second actuator extending through the top conductive collar, the second actuator coupled to the piston structure, the second actuator for advancing and retracting the second piston structure to advance and retract the second movable capacitor plate assembly relative to the second fixed capacitor plate assembly;

[0021] The first capacitor plate and the third capacitor plate include a plurality of interdigitated concentric cylindrical plates, and the second capacitor plate and the fourth capacitor plate include a plurality of interdigitated concentric cylindrical plates.

[0022] Another aspect of the present invention is to provide a method for adjusting the capacitance of a variable capacitor, comprising:

[0023] Providing a housing having an interior space, a top conductive collar, and a bottom contact assembly, the bottom contact assembly being electrically separated by a cylindrical insulating member;

[0024] providing a first movable capacitor plate assembly, the first movable capacitor plate assembly being disposed in the interior space of the housing, the first movable capacitor plate assembly comprising a first capacitor plate;

[0025] providing a second movable capacitor plate assembly, the second movable capacitor plate assembly being disposed in the interior space of the housing, the second movable capacitor plate assembly comprising a second capacitor plate;

[0026] providing 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;

[0027] providing a second flexible structure coaxial with 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;

[0028] providing a third flexible structure coaxial with and surrounding the first and second flexible structures, the third flexible structure having a first end sealed to the top conductive collar and a second end sealed to the second movable capacitor plate assembly;

[0029] providing a first fixed capacitor plate assembly, the first fixed capacitor plate assembly being disposed proximate to the first movable capacitor plate assembly, the first fixed capacitor plate assembly comprising a third capacitor plate;

[0030] providing a second fixed capacitor plate assembly disposed proximate to the second movable capacitor plate assembly, the second fixed capacitor plate assembly comprising a fourth capacitor plate;

[0031] providing a first actuator extending through the top conductive collar and through the first flexible structure, the distal end of the first actuator engaging the thrust collar, the first actuator being used to advance and retract the first movable capacitor plate assembly relative to the first fixed capacitor plate assembly;

[0032] providing a second actuator extending through the top conductive collar, the second actuator being coupled to the second movable capacitor plate assembly via a piston structure, the second actuator being used to advance and retract the second movable capacitor plate assembly;

[0033] wherein the first capacitor plate and the third capacitor plate comprise a plurality of interdigitated concentric cylindrical plates, and the second capacitor plate and the fourth capacitor plate comprise a plurality of interdigitated concentric cylindrical plates; and,

[0034] The first actuator is actuated to adjust the capacitance between the first capacitor plate and the third capacitor plate, and the second actuator is actuated to adjust the capacitance between the second capacitor plate and the fourth capacitor plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The disclosure of the present invention can be better understood with reference to the accompanying drawings and the following detailed description:

[0036] Figure 1 is an external isometric view of a coaxial variable capacitor according to one or more embodiments;

[0037] Figure 2 for Figure 1 A cutaway isometric view of a coaxial vacuum variable capacitor is shown;

[0038] Figure 3A , Figure 3B , Figure 3C and Figure 3D for Figure 1 An isometric cross-sectional view of a vacuum variable capacitor shown in FIG. 1 ; wherein the electrode plate assemblies are arranged in various relative positions;

[0039] Figure 4 for Figure 1 A cutaway isometric exploded view of a first capacitor plate, a second capacitor plate, a third capacitor plate, and a fourth capacitor plate of the coaxial vacuum variable capacitor shown;

[0040] Figure 5 for Figure 1 A cutaway isometric exploded view of concentric capacitor plates in a coaxial variable capacitor is shown;

[0041] Figure 6 for Figure 1 An exploded isometric view of a plurality of flexible structures in a coaxial variable capacitor is shown; and

[0042] Figure 7 is a schematic diagram of a matching network including a coaxial variable capacitor according to one or more embodiments.

[0043] It should be emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the sizes of various features may be arbitrarily increased or reduced for clarity of discussion or ease of illustration.

[0044] Figure numerals: 100: coaxial variable capacitor; 102: housing; 104: actuator end cap; 106: top conductive collar; 108: bottom contact assembly / conductive collar; 110: intermediate cylindrical insulator / intermediate electrical insulating assembly; 114: actuator; 115: threaded actuator; 118: movable capacitor assembly / movable capacitor plate assembly; 120: fixed capacitor plate assembly; 122: movable capacitor assembly / first movable Capacitor plate assembly / removable capacitor plate assembly; 124: movable capacitor assembly / second movable capacitor plate assembly; 128: fixed capacitor assembly / third capacitor plate assembly; 129: bottom surface / bottom surface; 130: fixed capacitor assembly / fourth capacitor plate assembly; 131: bottom surface / bottom surface; 132: cylindrical blade; 134: cylindrical blade; 136: cylindrical blade; 138: cylindrical blade; 140: Insulating ring; 142: flexible structure; 144: flexible structure; 146: flexible structure; 148: first mounting annular channel; 150: upper surface; 152: second mounting annular channel; 154: cylindrical piston structure / thrust collar; 155: threaded actuator; 156: third mounting annular channel; 158: upper surface; 160: gasket; 162: thrust collar; 164: extension coupling; 166: sealed volume; 800: Matching network; 802: matching branch; 804: shunt branch; 806: RF input; 808: first variable capacitor; 810: second capacitor; 812: third variable capacitor; 814: inductor; 816: fourth variable capacitor; 818: fifth variable capacitor; 820: inner coil; 822: sensor; 824: outer coil; 826: sensor; 828: sensor; 830: sixth capacitor; 832: dotted line. DETAILED DESCRIPTION

[0045] The following is only an exemplary illustration of the technical solution of the present invention. For the purpose of clear discussion, not all features of the specific embodiments involved in each embodiment are described in the specification of the present invention. It is understood that in the development process of any such actual implementation, in order to achieve the specific goals of the developer, many implementation-specific decisions may be made, such as following system-related and business-related constraints, which may vary between different implementations. In addition, it should be understood that although such development work may be complex and time-consuming, it is still a routine task for those of ordinary skill in the art who benefit from the disclosure of the present invention.

[0046] In the present disclosure, expressions such as "comprising", "including", "may include", and "may comprise" indicate the presence of the disclosed functions, operations, and constituent components, but do not limit the presence of one or more additional functions, operations, and constituent components. In the present disclosure, terms such as "including" and / or "having" may be interpreted to represent a certain characteristic, quantity, operation, constituent component, component, or a combination thereof, but should not be interpreted to exclude the presence or possibility of adding one or more other characteristics, quantities, operations, constituent components, components, or a combination thereof.

[0047] As used herein, the article "a" is intended to have its ordinary meaning in the field of patent technology, i.e., "one or more". In this document, unless otherwise expressly specified, when the term "about" is used in connection with a numerical value, it generally refers to within the tolerance range of the device used to generate that numerical value, or in some examples, it refers to ±10%, or ±5%, or ±1%. Additionally, in this document, as used herein, the term "substantially" means most, almost all, or all, or for example, it refers to an amount within the range of about 51% to about 100%. Furthermore, the examples in this document are illustrative only and are presented for purposes of discussion and not as a limitation.

[0048] As used herein, "providing" an article means having ownership of and / or control over the article. This may include, for example, forming (or assembling) part or all of the article from its constituent materials, and / or obtaining ownership and / or control of the formed article.

[0049] As used herein, "coaxial" refers to a relationship between two structures having coincident axes, such as a first cylindrical structure surrounding a second cylindrical structure, and they each have the same axis.

[0050] Unless otherwise defined, all terms used herein, including technical and / or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Additionally, unless otherwise defined, all terms defined in commonly used dictionaries should not be over-interpreted.

[0051] The following describes embodiments of a coaxial variable capacitor and a coaxial variable capacitor with a liquid dielectric material added between the capacitor plates. In subsequent embodiments, for a variable capacitor with a given capacitor plate geometry, the liquid dielectric material can increase its effective maximum capacitance. For a variable capacitor with a given capacitor plate geometry, the liquid dielectric material can also further increase its electrical breakdown voltage. Since the liquid dielectric has the potential for higher thermal conductivity compared to a vacuum, for example, relative to a coaxial capacitor, the liquid dielectric material can further provide additional dissipation of thermal energy within the variable capacitor.

[0052] Figure 1 FIG. 1 is an external isometric view of a coaxial variable capacitor 100 according to one or more embodiments. The coaxial variable capacitor 100 includes a housing 102 having an actuator end cap 104 as described below. Figure 1 In one embodiment shown, the housing 102 includes a top conductive collar 106 and a bottom contact assembly 108, which are electrically insulated from each other by an intermediate cylindrical insulator 110, which is bonded to the top conductive collar 106 and the bottom contact assembly 108 in a gas-tight manner. In some embodiments, the top conductive collar 106 and the conductive collar 108 can be metal, such as silver-plated copper, copper, brass, aluminum, or aluminum brazing. In some embodiments, the intermediate electrical insulating component 110 can be substantially cylindrical and can be made of ceramic or other suitable insulating materials. A threaded actuator 115 can surround the actuator end cap 104.

[0053] The upper end of the actuator 114 extends beyond the actuator end cap 104. In some embodiments, as described below, the actuator 114 can be threaded and can be rotated to advance and retract the movable capacitor assembly 124 relative to the fixed capacitor assembly 130 within the housing 102. In other embodiments, the actuator 114 can be advanced and retracted by a linear motor, a solenoid configuration, or a hydraulic or pneumatic system. Similarly, as described below, the threaded actuator 115 can be driven to advance and retract the movable capacitor assembly 122 relative to the fixed capacitor assembly 128 within the housing 102.

[0054] Figure 2 FIG3 is a cross-sectional isometric view of a coaxial variable capacitor 100 according to one or more embodiments. Figure 4 1 is a front cross-sectional view of a coaxial variable capacitor 100, wherein a movable capacitor plate assembly 118 and a fixed capacitor plate assembly 120 are contained within a 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 shown herein, in some embodiments, the movable capacitor plate assembly 122 can be independently moved from the 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 outer annular conductive contact of the contact assembly 108. The bottom surface 131 of the fourth capacitor plate assembly 130 defines an inner annular conductive contact of the contact assembly 108.

[0055] Figure 41 is a cross-sectional exploded isometric view of isolated capacitor plate assemblies 122, 124, 128, and 130. In certain embodiments, each of the capacitor plate assemblies 122, 124, 128, and 130 includes a plurality of concentric cylindrical blades 132, 134, 136, and 138, respectively, and maintains a coaxial orientation within the housing 102 such that the cylindrical blades 132 and 136 corresponding to the capacitor plate assemblies 122 and 128, respectively, can be interdigitated, and the cylindrical blades 134 and 138 corresponding to the capacitor plate assemblies 124 and 128, respectively, can be interdigitated. Figure 6 An enlarged, exploded, isometric view of capacitor plate assemblies 122 and 128 and their respective corresponding blades 132 and 138 is shown.

[0056] like Figure 2 As shown, the fixed capacitor plate assembly 128 further includes an insulating ring 140, which separates and electrically isolates the capacitor plate assemblies 128 and 130 from each other. In some embodiments, the insulating ring 140 may be made of ceramic or other suitable insulating materials.

[0057] In some embodiments (not shown in the drawings), the height of one or more of the capacitor plate assemblies 122, 124, 126, and 128 can vary, for example, from a maximum height in the center portion of the capacitor plate coil to a minimum height in the outer portion of the capacitor plate coil (as used herein, the term "height" when describing a capacitor plate refers to the dimension of the capacitor plate extending away from each mounting plate). Providing a capacitor plate with a variable height can make the capacitance-position relationship curve of a pair of capacitor plates closer to a power function rather than a linear function, and can also make the impedance-position relationship curve closer to a linear function rather than a power function. This concept is discussed in more detail in the above-mentioned patent application US17 / 739745.

[0058] In certain embodiments, the first capacitor plate assembly 118 and the second capacitor plate assembly 120 are configured such that the first capacitor plate assembly 122 can be at least partially interdigitated concentrically with the third capacitor plate assembly 128, and the second capacitor plate assembly 124 can be at least partially interdigitated concentrically with the fourth capacitor plate assembly 130. In certain embodiments, the first capacitor plate assembly 122 and the third capacitor plate assembly 128 are not in direct contact with each other, and the second capacitor plate assembly 124 and the fourth capacitor plate assembly 130 are not in direct contact with each other.

[0059] As described herein, 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 can be adjusted to vary the length of the concentric overlapping interdigitations between the first capacitor plate 118 and the third capacitor plate assembly 128 and to vary the length of the concentric overlapping interdigitations between the second capacitor plate assembly 124 and the fourth capacitor plate assembly 130. As described herein, the variation in the spacing between the first capacitor plate assembly 122 and the third capacitor plate assembly 128 can be independently adjusted relative to the spacing between the second capacitor plate assembly 124 and the fourth capacitor plate assembly 130. Likewise, the first capacitor plate assembly 122 can be independently raised or lowered relative to the third capacitor plate assembly 128 as compared to the raising or lowering of the second capacitor plate assembly 124 relative to the fourth capacitor plate 130. Thus, variations in the interdigitation of capacitor plate assembly pairs 122 / 128 and / or 124 / 130 may allow for adjustment of the effective capacitance of capacitor plate assembly pairs 122 / 128 and 124 / 130. In certain embodiments, capacitor plate assemblies 122, 124, 128, and 130 may be made of materials conventionally used for such structures in variable capacitors (e.g., oxygen-free copper or copper-plated brass).

[0060] Figure 3A , Figure 3B , Figure 3C and Figure 3D FIG. 1 is an isometric cross-sectional view of a coaxial variable capacitor 100 according to one or more embodiments; wherein capacitor plate assemblies 122 , 124 , 128 , and 130 are in various relative positions. Specifically, Figure 3A It is shown that the first (movable) capacitor plate assembly 122 is raised to a maximum distance away from the third (fixed) capacitor plate assembly 128, thereby providing a minimum capacitance between the capacitor plate assemblies 122 and 128; the second (movable) capacitor plate assembly 124 is raised to a maximum distance away from the fourth (fixed) capacitor plate assembly 130, thereby providing a minimum capacitance between the capacitor plate assemblies 124 and 130.

[0061] Figure 3B It is shown that the first (movable) capacitor plate assembly 122 is lowered to a minimum distance away from the third (fixed) capacitor plate assembly 128, thereby providing the maximum capacitance between the capacitor plate assemblies 122 and 128; the second (movable) capacitor plate assembly 124 is lowered to a minimum distance away from the fourth (fixed) capacitor plate assembly 130, thereby providing the maximum capacitance between the capacitor plate assemblies 124 and 130.

[0062] Figure 3CThe first (movable) capacitor plate assembly 122 is shown raised to its maximum distance away from the third (fixed) capacitor plate assembly 128, thereby providing a minimum capacitance therebetween; the second (movable) capacitor plate assembly 124 is shown lowered to a minimum distance away from the fourth (fixed) capacitor plate assembly 130, thereby providing a maximum capacitance therebetween.

[0063] Figure 3D The first (movable) capacitor plate assembly 122 is shown lowered to its minimum distance away from the third (fixed) capacitor plate assembly 128, thereby providing the maximum capacitance therebetween; the second (movable) capacitor plate assembly 124 is shown raised to its maximum distance away from the fourth (fixed) capacitor plate assembly 130, thereby providing the minimum capacitance therebetween.

[0064] In various embodiments, the spacing distances between the capacitor plate assembly pairs 122 / 128 and 124 / 130 can be independently adjusted to Figures 3A to 3D Any intermediate distance between the extreme positions allows the capacitance between the capacitor plate assembly pairs 122 / 128 and 124 / 130 to have a certain adjustment range.

[0065] Continue to refer Figure 2 and Figures 3A to 3D , especially refer to Figures 3A to 3D As shown herein, in one or more embodiments, a plurality of flexible structures 142, 144, and 146 are hermetically attached to the top conductive collar 106 and the various capacitor plate assemblies 122 and 124. In various embodiments, as shown in FIG. Figures 2 to 4 As shown, the flexible structures 142 , 144 , and 146 include compressible bellows structures. In various embodiments, the flexible structures 142 , 144 , and 146 may be made of a conductive material to provide a conductive path between the capacitor plate assemblies 122 and 124 and the top conductive collar 106 .

[0066] like Figure 2 and Figures 3A to 3D In the illustrated embodiment, the flexible structure 142 is coupled at one end to a first mounting annular aperture 148 on the bottom side of the top conductive collar 106 and at its opposite end to an upper surface 150 of the capacitor plate assembly 122. A flexible structure 144 coaxial and concentric with the flexible structure 142 is coupled at one end to a second mounting annular aperture 152 on the bottom side of the top conductive collar 106 and at its opposite end to a cylindrical piston structure 154 that is coupled to the threaded actuator 115. A flexible structure 146 coaxial and concentric with the flexible structures 142 and 144 is coupled at one end to a third mounting annular aperture 156 and at its opposite end to an upper surface 158 of the second capacitor plate assembly 124. Figure 7 is an exploded isometric view of coaxial flexible structures 142 , 144 , and 146 according to one or more embodiments.

[0067] like Figures 3A to 3D As shown, the actuator 114 extends through one or more bearings or washers 160 in the actuator end cap 104 and through a through hole in the conductive collar 106, thereby extending partially into the flexible structure 146. In one or more embodiments, the actuator 114 threadably engages the thrust collar 154.

[0068] Continue to refer Figure 2 , Figures 3A to 3D and Figure 4 , especially referring to FIG. 3 and Figure 4 , the sealed volume 166 is defined within the housing 102 ( Figures 3A to 3D Multiple reference numerals 166 appear in the figure to indicate the range of the sealed volume 166).

[0069] In certain embodiments, certain specific areas within the housing 102 may be at or near external atmospheric pressure due to the nominal seal that may be employed between the actuator 114 and the bearing or gasket 160 when the actuator 114 enters the actuator end cap 104. On the other hand, due to the sealed attachment of the flexible structures 142, 144, and 146 to the top conductive collar 106 and to the first capacitor plate assembly 122, the piston structure 154, and the second capacitor plate assembly 124, as previously described, the sealed volume 166 is hermetically (i.e., vacuum and liquid-tight) sealed.

[0070] According to certain embodiments of the present invention, the degree of interdigital overlap between the first capacitor plate assembly 122 and the third capacitor plate assembly 128, and the resulting effective capacitance of the capacitor plate assembly pair 122 / 128, can be adjusted via rotation of the actuator 114. Similarly, the degree of interdigital overlap between the second capacitor plate assembly 124 and the fourth capacitor plate assembly 130, and the resulting effective capacitance of the capacitor plate assembly pair 124 / 130, can be adjusted via rotation of the threaded actuator 115. Rotation of the actuator 114, such as by a stepper motor or 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, such as by a belt, a stepper motor, or otherwise, causes the threaded actuator 155 to be raised or lowered.

[0071] In certain embodiments, the flexible structures 142 / 144 / 146, the extension coupling 164, the thrust collar 162, and the piston structure 154 are conductive (e.g., metal) and provide a low resistance conductive 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 previously described, the bottom surface 129 of the third capacitor plate assembly 128 serves as the other contact of the coaxial variable capacitor 100, and the bottom surface 131 of the fourth capacitor plate assembly 130 serves as the other contact of the coaxial variable capacitor 100.

[0072] In various embodiments, as shown herein, coaxial variable capacitors can achieve high power density, current handling capability, and high voltage handling capability in a small volume. Having multiple pairs (two or more pairs) of capacitor plates, such as the interdigitated cylindrical blades described herein, can maintain the high voltage breakdown and high current handling capability of the variable capacitor without the additional volume required for the dielectric of the vacuum mechanism. Coaxial symmetry maximizes volumetric efficiency and allows all electrode assemblies to be sealed (e.g., brazed) to one structure. In some embodiments, brazing of the internal components can be performed in one step.

[0073] One or more vacuum variable capacitors, e.g. Figures 1 to 6 The vacuum variable capacitors involved in the various embodiments can be used to tune or otherwise control matching networks in radio frequency electrical processing devices. Radio frequency plasma enhanced processing processes are widely used in semiconductor manufacturing to etch different 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 plasma, i.e., partially ionized gas, which is used to generate neutral species and ions from precursors inside a reaction chamber, provide energy for ion bombardment, and / or perform other actions. Radio frequency plasma enhanced processing processes are performed by known radio frequency processing devices.

[0074] The RF processing device may include an RF generator that transmits a signal to a plasma reaction chamber. An RF matching device having a variable impedance may be disposed between the RF generator and the plasma reaction chamber. The RF matching device may be controlled or tuned by the impedance change of the RF matching device. The tuning of the RF matching device reduces the reflected power from the plasma reaction chamber and / or the RF matching device, which may increase the power transmitted from the RF generator to the plasma reaction chamber and to the electric plasma processing process. During operation, the RF generator may be powered to form a plasma in the reaction chamber. After the source gas is injected into the reaction chamber and the reaction chamber is supplied with power by the RF generator, a plasma may be generated.

[0075] Under certain conditions, power supplied to the reaction chamber may be reflected back from the reaction chamber. One cause of reflected power may be a mismatch between the characteristic impedance of the system and the load formed by the plasma in the reaction chamber. To help prevent reflected power, a matching network may be provided between the RF generator and the reaction chamber. Such a matching network may include a plurality of variable capacitors or other impedance components. The variable capacitor may be tuned so that the complex impedance of the load in the reaction chamber matches the impedance of the RF generator.

[0076] Although various methods of controlling or tuning matching networks have been used, such methods may be unreliable and may not effectively result in impedance matching. The matching network may include a stepper motor with a specific number of steps, which is a function unique to the specific stepper motor. During operation, the capacitor may be driven by a motor with a percentage range of 0-100%, so the motor may have several clicks. Specific embodiments of the present invention may provide method descriptions and / or otherwise allow the capacitor position to be adjusted based at least in part on a "percentage of steps".

[0077] Turn to refer to Figure 7 , which shows a schematic illustration of a matching network including a variable capacitor (which may include the variable capacitor 100 described above) according to one or more embodiments. In one embodiment as shown in FIG. 8 , the matching network 800 shown therein has a matching branch 802 and a shunt branch 804. The matching branch 802 receives RF power from a radio frequency (RF) input 806. The 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, such as the variable capacitor 100 described in the present invention. Figures 1 to 6 The variable capacitor shown may have a rated power factor of approximately 10-2000 pF.

[0078] In one embodiment as shown in FIG. 8 , the first variable capacitor 808 is connected to the second capacitor 810, which is connected to ground. The second capacitor 810 is also connected to the third variable capacitor 812, which can also be a variable capacitor, such as Figures 1 to 6 The variable capacitor 812 is shown and its rated power factor may be about 10-2000 pF. The third variable capacitor 812 is also connected to an inductor 814 which is further connected to the shunt branch 804 .

[0079] The shunt branch 804 receives RF power from the matching branch 802, and the shunt branch 804 shunts the received RF power between the fourth variable capacitor 816 and the fifth variable capacitor 818. The fourth variable capacitor 816 and the fifth variable capacitor 818 can also be variable capacitors, such as Figures 1 to 6The variable capacitor shown may have a rated power factor of approximately 10-2000 pF.

[0080] The fifth variable capacitor 818 is connected to the inner coil 820. Between the fifth variable capacitor 818 and the inner coil 820, one or more sensors 822 may be provided. For example, the sensor 822 may be used to measure the voltage between the fifth variable capacitor 818 and ground. Similarly, the fourth variable capacitor 816 is connected to the outer coil 824. Between the fourth variable capacitor 816 and the outer coil 824, one or more sensors 826 may be provided. For example, the sensor 826 may be used to measure the voltage between the fourth variable capacitor 816 and ground.

[0081] The inner coil 820 may be further connected to ground and the outer coil 824 may be connected to a circuit system including a sensor 828 and a sixth capacitor 830. For example, the sensor 828 may be used to measure the voltage between the outer coil 824 and ground. The inner coil 820 and the outer coil 824 may be located outside the matching network 800 circuit system, such as Figure 7 The dashed line 832 is shown in FIG.

[0082] like Figure 7 The circuit system shown can be used to tune the first variable capacitor 808, the third variable capacitor 812, the fourth variable capacitor 816, and the fifth variable capacitor 818. By tuning the first variable capacitor 808, the third variable capacitor 812, the fourth variable capacitor 816, and the fifth variable capacitor 818, the power provided to the inner coil 820 and the outer coil 824 can be adjusted.

[0083] In a specific embodiment, a circuit system can be applied in the matching network 800 to serve as a current split ratio matching network. The circuit system can be controlled using a programmable logic controller (not shown in the figure). The programmable logic controller can be set in the matching network 800 or connected to the matching network 800 in other ways.

[0084] For the purpose of explanation, specific nomenclature is used in the above description to provide a thorough understanding of the content of the present invention. However, it is obvious to those with common knowledge in the art that the system and method described in the present invention can be implemented without specific details. The discussion of the above specific embodiments is only for the purpose of illustration and description. The embodiments of the present invention are not intended to be exhaustive or to limit the present invention to a specific form. In view of the above teachings, many equivalent modifications and variations are possible.

[0085] For example, although the embodiments described herein incorporate two coaxial capacitor plate pairs, it is contemplated that in other embodiments, more than two coaxial plate pairs may be incorporated. In addition, although the embodiments described herein relate to two or more movable coaxial plates that move simultaneously relative to two or more fixed coaxial plates, it is contemplated that in other embodiments, one or more of the coaxial plates may be advanced or retracted independently of the other coaxial plates.

[0086] The embodiments shown and described in the present invention are intended to better explain the principles and practical applications of the technical solutions of the present invention, so that other people with ordinary knowledge in the relevant technical field can better utilize the various embodiments disclosed in the present invention in combination with various modifications for specific purposes. The scope of protection of the present invention is defined by the scope of the claims and equivalent changes and modifications.

Claims

1. A variable capacitor, It is characterized in that The variable capacitor comprises: a housing having an interior space, a top conductive collar, and a bottom contact assembly, the bottom contact assembly being electrically separated by a cylindrical insulating member; a first movable capacitor plate assembly disposed in the interior space of the housing, the first movable capacitor plate assembly comprising a first capacitor plate; a second movable capacitor plate assembly disposed in the interior space of the housing, the second movable capacitor plate assembly comprising 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 and surrounding 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; a third flexible structure coaxial with and surrounding 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; a first fixed capacitor plate assembly disposed proximate to the first movable capacitor plate assembly, the first fixed capacitor plate assembly including a third capacitor plate; a second fixed capacitor plate assembly disposed proximate to the second movable capacitor plate assembly, the second fixed capacitor plate assembly including a fourth capacitor plate; a first actuator extending through the top conductive collar and through the first flexible structure, the distal end of the first actuator engaging the thrust collar, the first actuator being used to advance and retract the first movable capacitor plate assembly relative to the first fixed capacitor plate assembly; a second actuator extending through the top conductive collar, the second actuator coupled to the piston structure, the second actuator for advancing and retracting the second piston structure to advance and retract the second movable capacitor plate assembly relative to the second fixed capacitor plate assembly; The first capacitor plate and the third capacitor plate include a plurality of interdigitated concentric cylindrical plates, and the second capacitor plate and the fourth capacitor plate include a plurality of interdigitated concentric cylindrical plates.

2. The variable capacitor according to claim 1, It is characterized in that The first actuator includes a thread for engaging the thrust collar, and rotation of the first actuator in a first direction causes the first movable capacitor plate assembly to advance toward the first fixed capacitor plate assembly and expand the first flexible structure, and rotation of the first actuator in a second direction causes the first movable capacitor plate assembly to retract away from the first fixed capacitor plate assembly and contract the first flexible structure.

3. The variable capacitor according to claim 2, It is characterized in that When the second actuator advances into the housing, the second movable capacitor plate assembly advances toward the second fixed capacitor plate and expands the second flexible structure and the third flexible structure, and when the second actuator retracts outward from the housing, the second movable capacitor plate assembly retracts away from the second fixed capacitor plate and contracts the second flexible structure and the third flexible structure.

4. The variable capacitor according to claim 1, It is characterized in that The first flexible structure, the second flexible structure and the third flexible structure all include a bellows structure.

5. The variable capacitor according to claim 1, It is characterized in that The first capacitor plate, the second capacitor plate, the third capacitor plate, and the fourth capacitor plate each include a plurality of concentric cylindrical plates having a certain height.

6. The variable capacitor according to claim 1, It is characterized in that At least the first capacitor plate and the second capacitor plate each include a cylindrical coil having a higher height at a center portion of the cylindrical coil and a lower height at an outer portion of the cylindrical coil.

7. The variable capacitor according to claim 1, It is characterized in that 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 of the foldable concentric plates having a conical cross-section, the peak of the conical cross-section causing interdigitation to different degrees depending on the advancement and retraction of the movable capacitor plate assembly.

8. The variable capacitor according to claim 5, It is characterized in that The advancement and retraction of the first movable capacitor assembly causes the overlapping interdigitation degree of the first capacitor plate and the third capacitor plate to vary; And, wherein the advancement and retraction of the second movable capacitor plate assembly causes the overlapping interdigitation degree of the second capacitor plate and the fourth capacitor plate to change.

9. The variable capacitor according to claim 3, It is characterized in that The variable capacitor further comprises: A bottom contact assembly, the bottom contact assembly comprising an outer conductive ring, an inner conductive ring, and an insulator ring separating the outer conductive ring from the inner conductive ring; an intermediate electrical insulating component that separates the first conductive collar from the bottom contact assembly; 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, It is characterized in that The first flexible structure, the second flexible structure, and the third flexible structure provide an electrically conductive connection between the movable capacitor plate assembly and the first conductive collar.

11. The variable capacitor according to claim 1, It is characterized in that A vacuum is maintained in the interior space of the housing.

12. The variable capacitor according to claim 1, It is characterized in that The interior space of the housing contains a liquid dielectric.

13. A method of adjusting the capacitance of a variable capacitor, It is characterized in that The method comprises: Providing a housing having an interior space, a top conductive collar, and a bottom contact assembly, the bottom contact assembly being electrically separated by a cylindrical insulating member; providing a first movable capacitor plate assembly, the first movable capacitor plate assembly being disposed in the interior space of the housing, the first movable capacitor plate assembly comprising a first capacitor plate; providing a second movable capacitor plate assembly, the second movable capacitor plate assembly being disposed in the interior space of the housing, the second movable capacitor plate assembly comprising a second capacitor plate; providing 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; providing a second flexible structure coaxial with 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; providing a third flexible structure coaxial with and surrounding the first and second flexible structures, the third flexible structure having a first end sealed to the top conductive collar and a second end sealed to the second movable capacitor plate assembly; providing a first fixed capacitor plate assembly, the first fixed capacitor plate assembly being disposed proximate to the first movable capacitor plate assembly, the first fixed capacitor plate assembly comprising a third capacitor plate; providing a second fixed capacitor plate assembly disposed proximate to the second movable capacitor plate assembly, the second fixed capacitor plate assembly comprising a fourth capacitor plate; providing a first actuator extending through the top conductive collar and through the first flexible structure, the distal end of the first actuator engaging the thrust collar, the first actuator being used to advance and retract the first movable capacitor plate assembly relative to the first fixed capacitor plate assembly; providing a second actuator extending through the top conductive collar, the second actuator being coupled to the second movable capacitor plate assembly via a piston structure, the second actuator being used to advance and retract the second movable capacitor plate assembly; wherein the first capacitor plate and the third capacitor plate comprise a plurality of interdigitated concentric cylindrical plates, and the second capacitor plate and the fourth capacitor plate comprise a plurality of interdigitated concentric cylindrical plates; and, The first actuator is actuated to adjust the capacitance between the first capacitor plate and the third capacitor plate, and the second actuator is actuated to adjust the capacitance between the second capacitor plate and the fourth capacitor plate.

14. The method according to claim 13, It is characterized in that The first actuator includes a thread for engaging an actuator thrust collar, and rotation of the first actuator in a first direction causes the first movable capacitor plate assembly to advance toward the first fixed capacitor plate assembly and expand the first flexible structure, and rotation of the threaded actuator in a second direction causes the first movable capacitor plate assembly to retract away from the first fixed capacitor plate assembly and contract the first flexible structure.

15. The method according to claim 14, It is characterized in that When the second actuator advances into the housing, the second movable capacitor plate assembly advances toward the second fixed capacitor plate and expands the second flexible structure and the third flexible structure, and when the second actuator retracts outward from the housing, the second movable capacitor plate assembly retracts away from the second fixed capacitor plate and contracts the second flexible structure and the third flexible structure.

16. The method according to claim 13, It is characterized in that The first flexible structure, the second flexible structure and the third flexible structure all include a bellows structure.

17. The method according to claim 13, It is characterized in that Independent advancement and retraction of each movable capacitor assembly independently varies the degree of overlapping interdigitation between the first movable capacitor plate assembly and the first fixed capacitor plate assembly, and varies the degree of overlapping interdigitation between the second movable capacitor plate assembly and the second fixed capacitor plate assembly.

18. The method according to claim 17, It is characterized in that The method further comprises: A top conductive collar is provided in electrical contact with the movable capacitor plate assembly, a contact assembly is provided in electrical contact with the fixed capacitor plate assembly, and an intermediate electrical insulating component is provided for separating the first conductive collar from the second conductive collar.

19. The method according to claim 18, It is characterized in that At least one of the first flexible structure, the second flexible structure, and the third flexible structure provides an electrically conductive connection between a movable capacitor plate assembly and the top conductive collar.

20. The method according to claim 13, It is characterized in that The method further comprises: A liquid dielectric is provided in the interior space of the housing.

21. The method according to claim 13, It is characterized in that The method further comprises: A vacuum is maintained in the interior space of the housing.

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