Resonant LC Structure Using Standalone Capacitors

Abstract

The resonant coil includes a plurality of conductors forming a plurality of inductively coupled current loops, including a first conductor having a first end and a second end separated by a first gap, and a second conductor having a third end and a fourth end separated by a second gap, and at least one standalone capacitor having at least one first capacitor connected to the first and second ends of the first conductor.

Description

[Technical Field]

[0001] The devices and techniques described herein relate to LC structures that have stand-alone capacitors. [Background technology]

[0002] Electrical conductors capable of handling high-frequency (HF) alternating current (AC) without high losses are useful for constructing high-performance magnetic components used in inductors and transformers for power conversion, RF and microwave circuits, and for generating external magnetic fields for use in wireless power transmission, induction heating, and magnetic hyperthermia. Electrical conductors operating at high frequencies suffer from the skin effect and proximity effect, resulting in high power losses. The former restricts HF current to the surface of the conductor, thereby significantly reducing the conductor's effective cross-sectional area. The latter causes the magnetic field from one conductor to create additional losses in adjacent conductors and results in nonuniform current densities between the conductors.

[0003] As a result of skin and proximity effects, the amount of effective cross-sectional area of ​​a conductor carrying current is limited to less than twice the conductor's skin depth at the operating frequency. At frequencies up to approximately 1 MHz, this limitation can be overcome using litz wire, which is made up of multiple individually insulated thin strands twisted together. However, to effectively use litz wire, the individual strands must be much thinner than the skin depth at the operating frequency. As described in U.S. Patent Nos. 5,629,997 and 5,929,997, higher performance than litz wire has been demonstrated by multilayer conductors with integrated capacitors for resonant power conversion and wireless power transfer applications. Such structures are formed from many foil conductors with approximately equal current density, including integrated capacitance due to dielectric layers separating the foil conductors from each other. These multilayer conductors with integrated capacitors offer high performance because foil conductors are available in much smaller thicknesses compared to litz wire strands. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 10,109,413 [Patent Document 2] PCT Application No. PCT / US2017 / 043377 Summary of the Invention

[0005] Some aspects relate to a resonant coil comprising: a plurality of conductors forming a plurality of inductively coupled current loops, the plurality of conductors including a first conductor having a first end and a second end, the first end and the second end being spaced apart by a first gap; and a second conductor having a third end and a fourth end, the third end and the fourth end being spaced apart by a second gap; and at least one standalone capacitor having at least one first capacitor connected to the first end and the second end of the first conductor.

[0006] The first gap may be substantially aligned with the second gap. The first conductor and the second conductor may be on respective layers of a printed circuit board. The at least one stand-alone capacitor may provide a resonant capacitance for the resonant coil.

[0007] The capacitance between the first conductor and the second conductor may not contribute substantially to the resonant capacitance. The at least one stand-alone capacitor may further include at least one second capacitor connected to the third end and the fourth end of the second conductor.

[0008] The first conductor and the second conductor may be galvanically isolated from each other. The first conductor and the second conductor may be galvanically connected to each other. The galvanic connection may be formed by making a gap between the first conductor and the second conductor and connecting respective ends of the gap between the first conductor and the second conductor.

[0009] Some of the conductors may be galvanically isolated from one another, and some of the conductors may be galvanically connected to one another, and the galvanic connection may be formed by making a cut between the first conductor and the second conductor and connecting respective ends of the cut between the first conductor and the second conductor.

[0010] The first conductor and the second conductor may each have a C-shape. The first conductor and the second conductor may be planar. Each of the first conductor and the second conductor may have a toroidal C-shape with an open or closed cross section.

[0011] The first conductor may be nested within the second conductor. The at least one stand-alone capacitor may comprise a plurality of stand-alone capacitors having interleaved connections to at least the first conductor and the second conductor.

[0012] The resonant coil may further include a third conductor on the outside of an edge of the first conductor, and the first conductor may have a width smaller than that of the first conductor. The first conductor and the second conductor may have different thicknesses.

[0013] The first conductor and the second conductor may be substantially concentric. Some embodiments relate to a resonant coil including multiple galvanically isolated current loops with one or more stand-alone capacitors, the galvanically isolated current loops being strongly inductively coupled to one another.

[0014] Some embodiments relate to a resonant coil having multiple galvanically isolated current loops within a winding region connected to multiple standalone capacitors, the galvanically isolated current loops being inductively coupled to one another, a magnetic coupling coefficient between adjacent galvanically isolated current loops being greater than k=0.1, and / or a spacing between adjacent galvanically isolated current loops being less than 1 / 3 of an average diameter of the galvanically isolated current loops.

[0015] The magnetic coupling coefficient between adjacent galvanically isolated current loops may be greater than k=0.8, and / or the space between adjacent galvanically isolated current loops may be less than 1 / 10 of the average diameter.

[0016] The magnetic coupling between adjacent galvanically isolated current loops may be greater than k=0.9 and / or the spacing between adjacent galvanically isolated current loops may be less than 1 / 15 of the average diameter.

[0017] Some embodiments relate to a resonant coil having multiple C-shaped current loops with multiple standalone capacitors within a winding region, wherein each current loop is spaced apart by a dielectric layer such that each current loop is galvanically isolated, each current loop is substantially concentric, and gaps in the C-shaped cross section of each current loop are at substantially the same circumferential position.

[0018] Some embodiments relate to a resonant coil having multiple washer-shaped current loops within a winding region having one or more gaps, each of the gaps having at least one standalone capacitor, each of the current loops being separated by a dielectric layer such that each layer is galvanically isolated, the multiple current loops being substantially concentric, and the washer gaps being at substantially the same circumferential position.

[0019] Some embodiments relate to a resonant coil having multiple nested toroidal shaped current loops within a winding region having one or more gaps, each of the gaps having at least one standalone capacitor, each conductor being separated by a dielectric layer such that each layer is galvanically isolated, the multiple current loops being substantially concentric, and the gaps in the washer being at substantially the same circumferential position.

[0020] Some embodiments relate to a resonant coil having multiple nested toroidal shaped current loops within a winding region having one or more gaps, each of the gaps having at least one standalone capacitor, each current loop being separated by a dielectric layer such that each layer is galvanically isolated, the current loops being substantially concentric, the gaps in the washer being at substantially the same circumferential location, the current loops being inductively coupled, a magnetic coupling coefficient between adjacent current loops being greater than k=0.1, and / or the spacing between adjacent current loops being less than ⅓ of the average diameter of the current loops.

[0021] Some embodiments relate to a resonant coil having multiple nested toroidal shaped current loops within a winding region having one or more gaps, each of the gaps having at least one standalone capacitor, each current loop being separated by a dielectric layer such that each layer is galvanically isolated, the multiple current loops being substantially concentric, the gaps in the washer being at substantially the same circumferential location, the multiple current loops being inductively coupled, a magnetic coupling coefficient between adjacent current loops being greater than k=0.8, and / or the spacing between adjacent current loops being less than 1 / 10 of the average diameter of the multiple current loops.

[0022] Some embodiments relate to a resonant coil having multiple nested toroidal shaped current loops within a winding region having one or more gaps, each of the gaps having at least one standalone capacitor, each current loop being separated by a dielectric layer such that each layer is galvanically isolated, the multiple current loops being substantially concentric, the gaps in the washer being at substantially the same circumferential location, the multiple current loops being inductively coupled, a magnetic coupling coefficient between adjacent current loops being greater than k=0.9, and / or the spacing between adjacent current loops being less than 1 / 15 of the average diameter of the multiple current loops.

[0023] Some embodiments relate to a resonant coil having a plurality of multi-turn current loops in a winding region, each current loop having at least one stand-alone capacitor, the plurality of multi-turn current loops being inductively coupled, a magnetic coupling coefficient between adjacent current loops being greater than k=0.1, and / or a spacing between adjacent current loops being less than 1 / 3 of the average diameter of the current loops.

[0024] Some embodiments relate to a resonant coil having a plurality of multi-turn current loops in a winding region, each current loop having at least one stand-alone capacitor, the plurality of multi-turn current loops being inductively coupled, a magnetic coupling coefficient between adjacent current loops exceeding k=0.8, and / or a spacing between adjacent current loops being less than 1 / 10 of the average diameter of the current loops.

[0025] Some embodiments relate to a resonant coil having a plurality of multi-turn current loops in a winding region, each current loop having at least one stand-alone capacitor, the plurality of multi-turn current loops being inductively coupled, a magnetic coupling coefficient between adjacent current loops exceeding k=0.9, and / or a spacing between adjacent current loops being less than 1 / 10 of the average diameter of the current loops.

[0026] The device may comprise a resonant coil and a high permeability magnetic material for forming the magnetic field, optionally the high permeability magnetic material forming a pot core or toroid. The conductor may have varying thickness, optionally decreasing in size in the high field region.

[0027] The one or more stand-alone capacitors may be arranged in an alternating fashion. The standalone capacitors may have equal capacitance. A plurality of stand-alone capacitors may have increased capacitance due to an increase in the thickness of the conductor to which the stand-alone capacitors are secured.

[0028] The capacitance may increase approximately proportionally with an increase in the thickness of the conductor. The plurality of stand-alone capacitors may have a capacitance that increases in regions of high magnetic field.

[0029] Some embodiments relate to a resonant coil that includes at least one planar multi-turn spiral current loop. Some embodiments relate to a resonant coil that includes at least two planar multi-turn spiral current loops inductively coupled to one another.

[0030] Some embodiments relate to a resonant coil including at least one planar multi-turn spiral current loop with at least one stand-alone capacitor, and at least one spiral current loop with at least one stand-alone capacitor, the spiral current loop galvanically connected to the planar multi-turn spiral current loop.

[0031] Some aspects relate to methods of making or using any of the devices described herein. The resonant coil may further comprise a multi-layer conductor having an integrated capacitor structure inductively coupled to the plurality of inductively coupled current loops of the resonant coil.

[0032] The multilayer conductor with the integrated capacitor structure may be located in a region of a magnetic field higher than the magnetic field of the plurality of inductively coupled current loops. The above summary is provided by way of example and is not intended to be limiting.

[0033] In the drawings, each identical or nearly identical component shown in various figures is represented by a like reference numeral. For clarity, not every component is labeled in every drawing. The drawings are not necessarily drawn to scale, emphasis instead being placed upon illustrating various aspects of the techniques and devices described herein. [Brief explanation of the drawings]

[0034] [Figure 1A] FIG. 1A shows an example of a resonant coil having two layers of thin C-shaped conductors separated from each other by a dielectric layer and its equivalent circuit, according to some embodiments. [Figure 1B] FIG. 1B illustrates an example of a resonant coil having two layers of thin C-shaped conductors separated from each other by a dielectric layer and its equivalent circuit, according to some embodiments. [Figure 1C] FIG. 1C illustrates an example of a resonant coil having two layers of thin C-shaped conductors separated from each other by a dielectric layer and its equivalent circuit, according to some embodiments. [Figure 1D] FIG. 1D illustrates an example of a resonant coil having two layers of thin C-shaped conductors separated from each other by a dielectric layer and its equivalent circuit, according to some embodiments. [Figure 2A] FIG. 1A illustrates an example of a resonant coil disposed within a magnetic core, according to some embodiments. [Figure 2B] FIG. 2B illustrates an example of a resonant coil disposed within a magnetic core, according to some embodiments. [Figure 2C] FIG. 2C illustrates an example of a resonant coil disposed within a magnetic core, according to some embodiments. [Figure 3]FIG. 3 illustrates a resonant coil with a 30° circumferential misalignment between gaps in conductors on different layers, according to some embodiments. [Figure 4] FIG. 4 shows images of a prototype according to the embodiment of FIGS. 2A-2D constructed using standard PCB processes with high-loss FR4 substrate as the dielectric layer, according to some embodiments. [Figure 5A] FIG. 5A shows a perspective view of a resonant coil having two gaps where the conductors on each layer each have a stand-alone capacitor, according to some embodiments. [Figure 5B] FIG. 5B shows a top view of a resonant coil having two gaps where the conductors on each layer each have a stand-alone capacitor, according to some embodiments. [Figure 5C] FIG. 5C shows a schematic diagram of a resonant coil having a gap with a galvanic connection, according to some embodiments. [Figure 5D] FIG. 5D illustrates a cross-sectional view of a resonant coil having a gap with a galvanic connection according to some embodiments. [Figure 6A] FIG. 6A shows a circuit diagram of a resonant coil with four ICCLs, according to some embodiments. [Figure 6B] FIG. 6B shows a prototype of an inductively coupled conductor with a stand-alone capacitor implemented using a four-layer PCB with an outer diameter of 2 cm, according to some embodiments. [Figure 6C] FIG. 6C shows a prototype of an inductively coupled conductor with a stand-alone capacitor implemented using a four-layer PCB with an outer diameter of 6.6 cm, according to some embodiments. [Figure 6D] FIG. 6D illustrates a layout of the prototype of FIGS. 6B and 6C, according to some embodiments. [Figure 7A] FIG. 7A shows the labels for the four conductor layers of the structure of FIG. 7B. [Figure 7B] FIG. 7B illustrates an interleaved pattern for connections between conductors and stand-alone capacitors, according to some embodiments. [Figure 8]FIG. 8 illustrates an ICCL layer in which one or more conductor traces may be added near the radially inner and radially outer conductors, according to some embodiments. [Figure 9A] FIG. 9A illustrates an example of a toroidal conductor of an ICCL, according to some embodiments. [Figure 9B] FIG. 9B illustrates an example of a toroidal conductor of an ICCL, according to some embodiments. [Figure 9C] FIG. 9C illustrates an example of a toroidal conductor of an ICCL, according to some embodiments. [Figure 9D] FIG. 9D illustrates an example of a barrel wound conductor of an ICCL, according to some embodiments. [Figure 9E] FIG. 9E is a side view showing one or more conductor traces added near the top and bottom of the barrel winding structure of FIG. 9D. [Figure 10] FIG. 10 illustrates an example of a multi-turn winding for an ICCL, according to some embodiments. [Figure 11] FIG. 11 illustrates an example of a multi-turn winding for an ICCL, according to some embodiments. [Figure 12] FIG. 12 shows that thicker conductors can be placed in regions of lower magnetic field according to some embodiments. [Figure 13A] FIG. 13A shows an embodiment of a resonant coil in which a multilayer conductor with an integrated capacitor structure can be placed over multiple ICCLs. [Figure 13B] FIG. 13B shows an exploded view of a multilayer conductor with an integrated capacitor structure, according to some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0035] The present inventors have developed a novel resonant structure for handling high frequency alternating currents, which includes an inductively coupled layer of thin (e.g., foil) conductor connected to a stand-alone capacitor to form an inductively coupled current loop (ICCL).

[0036] 1A shows an exploded perspective view of an example of a resonant coil 100 having two layers of thin, C-shaped conductors 2a, 2b separated from each other by a dielectric layer 4. The ends of each conductor 2a, 2b are galvanically connected to one or more standalone capacitors 6a, 6b. For example, standalone capacitor 6a is connected in series across both ends of conductor 2a, and standalone capacitor 6b is connected in series across both ends of conductor 2b. The thickness, radial, and circumferential directions of the resonant coil 100 are shown in FIG. 1A.

[0037] 1B shows a top view of a resonant coil 100 showing a conductor 2a having two ends, each with terminals A and B connected to a respective terminal of a standalone capacitor 6a, i.e., a standalone capacitor 6a connected in series between terminals A and B. The standalone capacitor 6a may be a single standalone capacitor or multiple standalone capacitors.

[0038] FIG. 1C shows a side view of resonant coil 100, illustrating that conductors 2a and 2b may contact both sides of dielectric layer 4. As shown in FIG. 1C, in some embodiments, the bottom layer of the resonant coil may be substantially the same as the top layer. That is, conductor 2b may have the same shape in top view as conductor 2a shown in FIG. 1B. Like conductor 2a, conductor 2b has two ends, each with terminals A and B connected to a respective end of standalone capacitor 6b. That is, standalone capacitor 6b is connected in series between terminals A and B of conductor 2b. Standalone capacitor 6b may be a single standalone capacitor or multiple standalone capacitors.

[0039] The conductors 2a, 2b may be galvanically isolated from each other by a dielectric layer 4. However, in other embodiments, one or more conductors on different layers may be galvanically connected to each other.

[0040] FIG. 1D is a circuit diagram of a resonant coil 100. The resonant coil 100 may be excited by an AC voltage (Vin). In this example, the resonant coil 100 includes two inductively coupled current loops (ICCLs) 8a and 8b. ICCL 8a includes a conductor 2a, represented by an inductance, and one or more standalone capacitors 6a, represented by a capacitance C1. ICCL 8b includes a conductor 2b, represented by an inductance, and one or more standalone capacitors 6b, represented by a capacitance C2. The ICCLs 8a and 8b are strongly inductively coupled to each other. This is due, at least in part, to the fact that the ICCLs 8a and 8b overlap each other significantly (in this case, completely) in a top view and also to the fact that the ICCLs 8a and 8b are close to each other in the thickness direction (separated from each other only by the dielectric layer 4 in this case). In some embodiments, the conductors (e.g., 2a and 2b) can be separated from each other in the thickness direction by a distance less than one-third of the maximum linear dimension of the conductor (e.g., 2a or 2b). In some embodiments, the magnetic coupling coefficient k between each ICCL may be relatively high (eg, at least 0.1).

[0041] After describing the structure of resonant coil 100 and its circuit diagram, further aspects of the components of resonant coil 100 will be described. As described above, standalone capacitors such as standalone capacitors 6a and 6b are distinct from the integrated capacitance between each layer of multiple conductors 2. Standalone capacitors 6a and 6b are distinct devices from conductors 2 or dielectric layers 4. In contrast, stacked conductors with integrated capacitors (as described in U.S. Pat. No. 10,109,413 and PCT Application PCT / US2017 / 043377) are not standalone capacitors because their capacitance is formed between the conductors themselves, and therefore have not only capacitive impedance but also inductive impedance of approximately the same order of magnitude. The use of standalone capacitors can provide very low losses while reducing the cost of construction compared to multilayer conductors with integrated capacitors.

[0042] Standalone capacitors can be formed by any of a variety of devices. Standalone capacitors are devices that have a predominantly capacitive (negative reactive) impedance at the desired operating frequency. They may have an inductive (positive reactive) impedance that is less than the capacitive impedance at the operating frequency, and optionally, an impedance that is less than 20% of the capacitive impedance at the operating frequency. In some embodiments, one or more of the standalone capacitors 6a, 6b are discrete capacitors. The standalone capacitors may have individual packaging that can be galvanically connected to an electrical conductor (e.g., by soldering). Standalone capacitors can include, but are not limited to, one or more of a ceramic capacitor, a film capacitor, a mica capacitor, a PTFE capacitor, a tantalum capacitor, a tantalum-polymer capacitor, a thin film capacitor, an electric double layer capacitor, a polymer capacitor, an electrolytic capacitor, a niobium oxide capacitor, a silicon capacitor, a variable capacitor, and any combination, network, or array of such devices.

[0043] The capacitance of the standalone capacitors can be selected for the desired magnitude of current flowing through each current loop, which mitigates skin and proximity effects and results in a high-performance (high-Q) electrical structure. Inductive coupling induces current in different current loops. Such a structure allows the effective use of multiple conductors with overall sizes (i.e., thicknesses) much larger than the skin depth at the operating frequency. Overall size refers to the sum of the thicknesses of the multiple conductors in a direction perpendicular to the plane of current flow (i.e., the approximate plane in which the thin conductors are arranged). For example, the overall size of a planar foil conductor refers to the sum of the foil conductor layer thicknesses, while the overall size of a toroidal conductor refers to the sum of the radial thicknesses of the winding region, as defined in Figure 9B.

[0044] The conductors (e.g., 2a, 2b) may have a thickness of less than or equal to twice the skin depth of the conductive material at the operating frequency. In some embodiments, the operating frequency may be at or near the resonant frequency of the resonant coil, while in other embodiments, the operating frequency and the resonant frequency may be completely different. An example of a resonant frequency close to the operating frequency is 6.9 MHz, while the operating frequency is 6.78 MHz. Depending on the application, the resonant coil can be configured to have a resonant frequency in the range of 10 kHz to 1 GHz. For example, the resonant frequency may be 10-100 kHz for automotive applications, 100-200 kHz for the Qi standard, approximately 1-3 MHz for medical devices, or in the frequency bands of 6.78 MHz or 13.56 MHz or higher for other applications.

[0045] A conductor is an electrical conductor that can be made of any conductive material or combination of materials, including, but not limited to, one or more metals such as silver, copper, aluminum, gold, and titanium, and non-metallic materials such as graphite. The conductive material may have a conductivity greater than 200 kS / m, and optionally greater than 1 MS / m. An electrical conductor may have any physical form, including, but not limited to, a solid material, a wire, a magnet wire, a stranded wire, a Litz wire, a foil conductor, a conductor laminated on a substrate, a printed circuit board trace, an integrated circuit trace, or any combination thereof. A foil conductor is an electrical conductor in which the size of the conductor in a direction perpendicular to the direction of current flow is much smaller (e.g., at least 10 times smaller) than the size of the conductor parallel to the direction of current flow. Some examples of foil conductors may include, but are not limited to, flat current loops (e.g., C-shaped, arc-shaped, rectangular, or any polygonal conductor), foil layers wrapped around a cylinder or a rectangular prism, barrel-wound conductors and edge-wound conductors, and / or foil layers forming a toroid or toroidal polyhedron having a circular, polygonal, or rounded polygonal cross section and which may have surfaces that are wholly or partially covered with one or more conductive materials.

[0046] The dielectric layer 4 may be any non-conductive material or combination of materials, including, for example, but not limited to, one or more of air, FR4, PLA, ABS, polyimide, PTFE, polypropylene, Rogers substrate, plastic, glass, alumina, or ceramic. The dielectric material may have a conductivity of less than 100 kS / m, optionally less than 1 S / m.

[0047] The resonant coil may optionally be placed within a magnetic core, as shown in Figures 2A-2C, which show top and perspective views, respectively, of a resonant coil 100 within a magnetic core 10, which in this example is a pot core.

[0048] The magnetic core may be composed, in whole or in part, of one or more ferromagnetic materials having a relative magnetic permeability greater than 1, optionally greater than 10. The magnetic core material may include, but is not limited to, one or more of iron, various steel alloys, cobalt, ferrites, including manganese-zinc (MnZn) and / or nickel-zinc (NiZn) ferrites, nano-granular materials such as Co-Zr-O, and powder core materials consisting of a powder of ferromagnetic material mixed with an organic or inorganic binder. However, the techniques and devices described herein are not limited with respect to the particular material of the magnetic core. The magnetic core may have any of the following shapes: pot core, sheet (I core), sheet with center post, sheet with outer rim, RM core, P core, PH core, PM core, PQ core, E core, EP core, EQ core, etc. However, the techniques and devices described herein are not limited to any particular magnetic core shape.

[0049] As shown in FIG. 2C, which shows a cross-sectional view, the resonant coil may be arranged in a winding region. A winding region is a continuous region or volume of space that defines a cross section through which a significant portion (e.g., >75%) of the structure's total current flows in only one direction (e.g., the circumferential direction). FIG. 2C shows an example of a resonant coil having multiple conductors arranged within the winding region 12 of a magnetic pot core. In this case, the winding region 12 is a toroid of rectangular cross section that surrounds the conductor 2. The current loops within the winding region may be approximately concentric (or coaxial), with the centers or central axes of the smallest circles that can enclose each current loop positioned closely to one another (i.e., at a distance less than the average of the radii of the smallest circles that can enclose each of the current loops). Approximately concentric current loops may include current loops on the same plane (e.g., the top layer of conductors in FIG. 2C) where larger current loops surround smaller current loops, or current loops on different planes whose centers are offset radially less than the radially innermost position of the largest current loop. Any polygonal or other shaped current loop containing any type or shape of conductor may occupy the winding area.

[0050] Resonant coils as described herein can be implemented using a variety of technologies, including, but not limited to, printed circuit board (PCB) processes, individually spaced conductors, foil conductors spaced apart by dielectric layers, foil conductors laminated, coated, deposited, electroplated, or sputtered onto various dielectric materials, and integrated circuit processes.

[0051] The present inventors have recognized a resonant coil conductor arrangement that can reduce excitation of capacitance formed between layers of an ICCL. As shown in FIGS. 1B and 1C, each conductor (e.g., conductors 2a and 2b) has a gap extending from one end of the conductor to the other. In the example of FIGS. 1B and 1C, the gaps between conductors 2b and 2c are aligned with each other in the circumferential direction. That is, as shown in FIG. 1C, the gaps between conductors 2b and 2c are stacked so that they are directly below or above each other. By aligning the gaps between the conductors of the resonant coil, excitation of the intervening dielectric layer 4 can be reduced or avoided. The reason that aligning the gaps reduces excitation of the intervening dielectric layer 4 is that, due to inductive coupling, the voltages of the conductors are substantially the same at each point along the circumference and radius of the resonant coil. Because a substantially zero voltage difference appears between the conductors (e.g., between conductors 2a and 2b), the component of the electric field extending through the thickness of the dielectric layer 4 is substantially zero. The dielectric layer 4 does not need to be made of a low-loss material because it is not excited by the voltage difference between the conductors of adjacent layers. The openings in different conductor layers do not need to be perfectly aligned to achieve a high-performance structure; even approximate alignment can provide performance similar to that of precise alignment. Approximate alignment can be within an angle of less than 45% of 180° divided by the number of gaps in each conductor layer (as discussed further below), or less than 30°. Figure 3 shows a resonant coil 200 similar to resonant coil 100, but with a 30° circumferential offset between the gaps in conductors 2a and 2b. The approximate alignment of the gaps allows for the fabrication of a high-Q coil from multiple conductors with an optional non-conductive dielectric layer 4.

[0052] FIG. 4 shows images of a prototype according to the embodiment of FIGS. 2A-2D, constructed using standard PCB processes with a lossy FR4 substrate as the dielectric layer 4. The prototype exhibited parallel resonance. The standalone capacitors 6a and 6b both have the same capacitance value. Despite the lossy FR4 substrate material (quality factor 59), the prototype achieved a quality factor of 765 at 6.8 MHz, a five-fold improvement over a typical coil fabricated on a PCB. For wireless power transmission applications, a higher quality factor for the coil can be used to achieve higher efficiency, higher power, longer range, and / or smaller size.

[0053] The inventors recognized that an inductive current loop may have one or more gaps in a conductor. Multiple gaps in an inductively coupled current loop can reduce the required voltage rating of a standalone capacitor. Again, a layout can be used that reduces the excitation of capacitance formed between layers. By circumferentially aligning gaps in adjacent layers, excitation of the substrate layer is reduced or eliminated. When multiple gaps are used in a conductor, attempting to align the gaps on each layer can reduce the excitation of capacitance from layer to layer. When subsequent layers have an uneven number of gaps or gaps at different circumferential positions, aligning one or more gaps can reduce the excitation of capacitance from layer to layer.

[0054] 5A and 5B are perspective and top views, respectively, of a resonant coil in which a conductor has two gaps. This structure is similar to resonant coil 100, except that conductors 22a and 22b each have two gaps, rather than a single gap like conductors 2a and 2b of resonant coil 100. One or more standalone capacitors are connected in series between the ends of the conductors separated by the gaps. For example, as shown in FIG. 5B, conductor 22a has standalone capacitor 26a1 connected in series through end terminals A and B of the first gap (Gap 1) and standalone capacitor 26a2 connected in series through end terminals C and D of the second gap (Gap 2). The inductively coupled current loop including second conductor 22b may be the same as the inductively coupled current loop including first conductor 22b, or the two may be aligned, as shown in FIG. 5A. In this example, the gaps are positioned 180 degrees apart from each other circumferentially around the resonant structure. However, the gaps may be positioned at other locations with different angular displacements. The resonant coil may include any number of gaps, such as one gap, two gaps, three gaps, four gaps, or more gaps, as the devices and techniques described herein are not limited in this respect.

[0055] The inventors recognize that some embodiments of ICCLs may have galvanic connections between different current loops. A galvanically connected ICCL (galvanically connected at each end of a current loop, with each current loop including a conductor connected in series with one or more standalone capacitors) may provide the same skin and proximity effect mitigation advantages as a galvanically isolated ICCL. Figures 5C and 5D show schematic and cross-sectional views, respectively, of a resonant coil similar to those of Figures 5A and 5B, but instead of including a standalone capacitor in series between terminals C and D, the terminals of each conductor 22a and 22b are galvanically connected to each other. That is, terminal C of conductor 22a is galvanically connected to terminal C of conductor 22b, and terminal D of conductor 22a is galvanically connected to terminal D of conductor 22b. Such connections may be formed by vias 5, as shown in Figure 5D. The gap with the galvanic connection (Gap 2) does not have to be 180 degrees away from Gap 1; such gaps can be located anywhere and can include any number of gaps with galvanic connections. The resonant coil can include any number of galvanic connections between each conductor 2.

[0056] Returning to the general description of resonant coils with ICCLs, a resonant coil may have any number of ICCLs, even more than two. For example, a resonant coil may have four ICCLs. A circuit diagram of a resonant coil with four ICCLs is shown in FIG. 6A. Prototypes of an inductively coupled conductor with a standalone capacitor implemented using four-layer PCBs with outer diameters of 2 cm and 6.6 cm are shown in FIGS. 6B and 6C, respectively. The top side of the PCB includes connections to the top two layers of the PCB, and the bottom side includes connections to the bottom two layers of the PCB. The 2 cm structure has a Q factor of 336 at 13.56 MHz, and the 6.6 cm structure has a Q factor of 732 at 6.78 MHz. Both of these structures are at least five times better than typical coils fabricated on PCBs of the same size.

[0057] The layout of the prototype PCB of Figures 6B and 6C is configured as shown in Figure 6D. For PCBs with two or more layers, the standalone capacitors may be located on the top or bottom of the PCB. For PCBs with two or more layers, vias may be formed to connect from the inner layers to the top and / or bottom of the PCB, as shown in Figure 6D. Figure 6D shows a resonant coil having four conductors 2a-2d, four sets of one or more standalone capacitors 6a-6d, and three dielectric layers 4 between each conductor. In Figure 6D, the radially inner standalone capacitors 6b and 6c are located on the top and bottom of the resonant coil, respectively, and are connected to the inner conductors 2b and 2c through corresponding vias 5 without a galvanic connection to conductor 2a or conductor 2d. The radially outer standalone capacitors 6b and 6e are connected to the outer conductors 2b and 2e, respectively, without vias. However, the techniques and apparatus described herein are not limited with respect to the location of the standalone capacitors or vias, and the standalone capacitors may be located at any radial position.

[0058] The inventors have recognized that interleaved connections between the conductors of an ICCL and standalone capacitors can reduce losses and therefore achieve higher performance. Interleaving refers to the alternating pattern of connections when viewed from the top, defined from the inside to the outside of the resonant coil. Interleaving is particularly useful for inductively coupled conductors, where gaps between one or more outer (e.g., top or bottom) conductors are used as spaces to provide electrical connections for one or more inner conductors to connect to standalone capacitors. For example, in FIG. 6C , a four-layer resonant coil is shown, with four capacitors connected to each of two solder pads on the top side of the PCB, such that the four radially outer capacitors are connected to the top layer and the four radially inner capacitors are connected to a second layer below the top layer. The solder pads for the bottom two layers are on the bottom side of the PCB. The performance of this structure using a four-layer PCB can be improved if the four capacitors for each of the outer and inner layers, as defined in FIG. 7A, are alternately or staggered as shown in FIG. 7B, with every other capacitor connected to the outer and inner layers, respectively. An outer layer refers to a layer on the top or bottom surface of the PCB so that vias are not required to reach it. An inner layer can be reached by vias. For example, in a two-layer PCB, the capacitors for the top layer are connected to the top surface, the capacitors for the bottom layer are connected to the bottom surface, and there are no inner layers. However, in a four-layer PCB, the two inner layers use vias to connect to the top and bottom surfaces, respectively. Interleaving can occur at various levels. For example, the four capacitors on each layer in the structure of FIG. 6C can be grouped into two groups of two capacitors each, and then these capacitors are interleaved, connecting from the center outward to layers II, O, II, O, II, O. Here, "I" represents an inner layer and "O" represents an outer layer. Other interleaved structures for eight capacitors are IIOOOOII, IIOIOOIO, or IOOIOOI.In general, for a total of N capacitors with M inductively coupled current loops, there can be MN permutations of the connections between the different capacitors and layers, and the inventors recognize that any of these permutations can be beneficial.

[0059] The inventors have recognized that for ICCLs with multiple gaps, it may be beneficial to use different interleaving combinations within the same conductor. This can force better current distribution and reduce losses in the coil. For example, consider a four-layer planar coil similar to that of FIG. 6C, but with two gaps instead of one in each conductive layer. In the same conductor, one gap may optionally have an interleaving pattern of IIOOIIO, while the other gap may have an interleaving pattern of OOIIOOII. The inventors have recognized that any combination of interleaving patterns for subsequent gaps may be beneficial. In other embodiments, the interleaving pattern may be the same for different gaps.

[0060] The structures shown in Figures 6D and 7B are inductive coupling structures using a four-layer PCB, with two layers connected to one side of the PCB and the other two layers connected to the other side. Depending on the application, some four-layer structures may have all four layers connected to only one side of the PCB. For PCBs with more layers, the number of layers connected to each side of the PCB may be greater than two. The present invention is not limited to two-layer and four-layer PCBs, but also applies to PCBs with more than one conductor, and is not limited to the specific side of the PCB to which each layer is connected and / or the different possible interleaving arrangements between capacitors on different layers. For example, an eight-layer PCB may have four layers connected to each side of the board, and the capacitors may be interleaved as 1-2-3-4-1-2-3-4 or 1-2-3-4-4-3-2-1, where the numbers 1-4 represent different conductor layers.

[0061] ICCLs can be driven by connecting one or more ICCLs to an AC power source. The inventors have recognized that performance may be improved if the connecting leads between the current loops and the power source are located in a region of relatively low (e.g., lowest) magnetic field and / or if these current loops are connected to stand-alone capacitors. For example, in a structure with ICCLs without galvanic connections between layers located within a magnetic pot core, the magnetic field strength increases from the bottom (closed side) to the top (open side) of the pot core and / or from the radially outer side to the radially inner side of the pot core. Therefore, the lowest losses occur when the connecting leads are located at the bottom of the pot core and close to the radially outer side of the pot core.

[0062] In some embodiments, the conductor of the resonant coil connected to the connecting lead can be composed of multiple turns. Multiple turns can be used to vary the impedance of the structure, thereby facilitating integration into power electronics. Alternatively, or in addition, multiple windings can be used to achieve voltage gain or voltage reduction. Multi-turn conductors are further described in connection with Figures 10 and 11.

[0063] For example, ICCLs implemented using PCB manufacturing processes may have edges in the conductor parallel to the current flow direction, around which a large portion of the current flows due to induced eddy currents in the conductor. This phenomenon, called lateral current crowding, occurs when current crowds laterally relative to the current flow direction, inducing excess AC power loss. In the resonant coils described herein, current may crowd at the radial inner and outer edges of conductor 2. The inventors have recognized that this lateral current crowding phenomenon can be mitigated by adding one or more additional current loops of reduced width near the edges of the main conductor. These additional current loops may or may not be galvanically connected to the main conductor. The current loops may include conductors having a thickness perpendicular to the current flow direction of up to five times the skin depth at the operating frequency, and may themselves be connected to standalone capacitors, which may be selected to select the desired current flowing through them. For example, as shown in the exemplary ICCL of FIG. 8, which may be formed using a PCB process, one or more conductor traces can be added near the radially inner and outer sides of the conductor. As shown in FIG. 8, a main conductor 2a1 has one or more inner conductors 2a2 and / or outer conductors 2a3 that are identical in shape but have a smaller radial width than the adjacent main conductor 2a1. Adding such additional traces or current loops can improve performance and reduce power loss in the structure. Finite element simulations have shown that the improvement (power loss reduction) can be up to 15% or more for each additional trace or current loop added. The inventors have recognized that such additional conductors or current loops can be beneficial in ICCL implementations that use other foil conductors, such that a current loop with a smaller physical conductor size may be added near the edge of another current loop with a larger conductor size.As shown in Figure 9E, by forming vertically spaced portions from the top and bottom of the cylinder, a structure similar to the barrel-wound structure of Figure 9D described below can be formed, which shows a side view of such a structure from a perspective that does not include the gap in Figure 9D. The current loops described in this paragraph reduce lateral current crowding and can be useful in a variety of applications. Reducing the magnetic core material can reduce mass and volume without significantly reducing performance. Furthermore, thin, high-performance coils can be achieved for height-constrained applications.

[0064] The structures and techniques described herein can be applied to any other type of conductor or combination of conductors, along with the exemplary ICCL implementation on a conductor layer and / or PCB. Some embodiments include ICCL implementations using foil conductors. One example of such an ICCL implementation using foil conductors is nested toroids with circular cross sections, as shown in FIGS. 9A and 9B, which show three toroids with different circular cross sections nested within each other. The toroids may be galvanically isolated from each other via a suitable dielectric material, including air. In other embodiments, the conductors may be galvanically connected to each other. Other examples include toroids or toroidal polyhedrons with various cross sections, such as a circle or a portion of a circle, a rectangle, a rectangle with rounded corners, a rectangle with one or more sides removed, or a combination of straight and curved lines. FIG. 9C shows, from left to right, a circle, a rectangle, a rectangle with rounded corners, a rectangle with one side removed, a combination of straight and curved lines, and a portion of a circle. In some embodiments, the ICCL is formed by wrapping a foil layer around a cylinder or prism, as shown in FIG. 9D. 9D shows an example of an ICCL using barrel-wound foil conductors wrapped around a cylinder, showing gaps in each conductor for connection to one or more stand-alone capacitors. In general, the techniques and structures described herein apply to ICCLs with any type of electrical conductor or foil conductor.

[0065] ICCLs are not limited to single-turn current loops and can be implemented using multi-turn current loops. For example, ICCLs can be modified to be multi-turn spirals, with each layer connected to one or more standalone capacitors. The multi-turn current loops may be inductively coupled, located within a winding region, or optionally within a magnetic core. There may be multiple current loops, each with multiple windings within each conductor layer. The multiple turns of a current loop may be implemented on different PCB layers using vias. However, such multi-turn implementations of ICCLs are not limited to PCBs. For example, multi-turn ICCLs using barrel-wound foil conductors (similar to FIG. 9D) or toroidal foil conductors (similar to FIG. 9A) can be implemented by wrapping groups of conductors in a spiral and / or helical shape.

[0066] The inventors have recognized that it may be advantageous to construct a planar spiral current loop using only one layer. This may be particularly useful for coils constructed on a PCB. As shown in FIG. 10, the spiral may be constructed in or on a single layer of a PCB by spiraling a conductor 102 inward toward the center. Each loop may have a gap where a bridge component 6c, 6d can be connected in series with the conductor 102. Pads 104 at the gaps in the conductor 102 allow for attachment (e.g., soldering) of the bridge components 6c, 6d. The bridge component may be a standalone capacitor that provides at least a portion of the resonant capacitance. The bridge component may be a low-impedance electrical component (e.g., a resistor and / or a conductive bridge with a resistance less than half the resistance of the entire conductor path). The conductor in the center of the spiral then exits the spiral immediately below each bridge component and / or between the bridge component attachment points. This planar spiral current loop may be used as a single resonant coil, optionally positioned near a magnetic core. Alternatively, multiple planar multi-turn spiral current loops can be inductively coupled to form an ICCL, which reduces parasitic capacitance, resulting in lower losses, allows the spiral coil to be constructed in a single layer, and reduces the voltage rating of the capacitor.

[0067] With or without galvanic connections, some embodiments of multi-turn ICCLs can be implemented with multiple multi-turn spiral windings, multiple planar multi-turn spiral current loops (an example of which is shown in FIG. 10), or multiple combinations of multiple multi-turn spiral windings and planar multi-turn spiral windings inductively coupled together. The inventors recognize that not every layer needs to have a return path that creates a break in the spiral. That is, not every layer needs to be a planar multi-turn spiral current loop (an example of which is shown in FIG. 10). FIG. 11 shows an example four-layer PCB with four approximately concentric layers A, B, C, and D, labeled in that order from bottom to top. Layers A and D can be constructed with planar multi-turn spiral current loops. Layer B can be a multi-turn spiral winding whose radially inner conductor has a via to the return path of Layer A. Layer C can be a spiral winding whose radially inner conductor has a via to the return path of Layer D. Optionally, any combination of vias connecting Layer B and / or Layer C to Layer A and / or Layer D can provide a return path for current exiting the inner portion of the spiral. Each layer may have one or more standalone capacitors. The result of this example is a four-layer series-resonant structure that can be built using a four-layer PCB. Analysis suggests that such a structure has on the order of one-quarter the loss of a single-layer structure.

[0068] The inventors have recognized that it may be beneficial for the conductors of a multi-turn ICCL to begin and end at approximately the same circumferential location. While perfect alignment may provide the best performance, loss reduction is possible even with circumferential misalignment between the respective ends of conductors on different layers. In some embodiments, the circumferential misalignment may be less than 60 degrees.

[0069] In some embodiments, the conductors of different current loops of an ICCL may have different thicknesses. The conductor thicknesses are defined, for example, in the vertical direction in FIGS. 1A and 1C and in the radial direction in FIG. 9. The inventors recognized and appreciated that the thickness of each conductor can be selected to improve the performance (e.g., loss) of the ICCL. Each conductor in an ICCL experiences two types of loss: loss due to the conductor's electrical resistance and loss due to the proximity effect, which induces eddy currents. The former is inversely proportional to the conductor's thickness, while the latter is directly proportional to the conductor's cubic thickness and the magnetic field strength squared. Therefore, depending on the local magnetic field strength, optimal conductor thicknesses exist at different locations within the winding region, with optimal conductor sizes being largest in regions of lowest magnetic field strength and smallest in regions of highest magnetic field strength. In the example shown in FIG. 12, the magnetic field increases from bottom to top. FIG. 12 illustrates an example of a resonant coil including four conductor layers, with the thickness decreasing from the bottom conductor to the top conductor. In some embodiments, the thickness of the thickest layer can be up to five times the skin depth at the operating frequency. In practice, commercially available conductor sizes can be selected that are closest to the required optimal conductor size. Selection of optimal or near-optimal conductor sizes based on local magnetic field strength can improve ICCL performance by up to 20%.

[0070] The inventors have recognized that ICCL performance can be further improved by selecting the capacitance of the standalone capacitors to achieve optimal current distribution among different current loops. For ICCLs with conductors of the same thickness, the standalone capacitors can be selected so that their capacitances are higher for current loops in regions of higher magnetic fields and lower for current loops in regions of higher magnetic fields. Such a selection reduces the current in current loops in regions of lower magnetic fields, thereby reducing the magnetic field in other regions of space and reducing AC power losses due to the proximity effect. For ICCLs with conductors of different thicknesses selected as described above, the standalone capacitors can be selected to have higher capacitances for thicker conductors and lower capacitances for thinner conductors to reduce losses in smaller conductors. These strategies for selecting the capacitance of the standalone capacitors can improve ICCL performance by up to 20% or more. Furthermore, for ICCLs with thick conductors, the standalone capacitors can be selected to be higher for conductors with the highest electric field and lower for conductors with the lowest electric field to reduce the proximity effect. These strategies for selecting standalone capacitors can improve ICCL performance by more than 20%.

[0071] Some embodiments include a combination of an ICCL with a standalone capacitor (as described in U.S. Pat. No. 10,109,413 and PCT Application PCT / US2017 / 043377) and a multilayer conductor with an integrated capacitor. One such implementation is a structure with an ICCL made with larger conductor sizes in the low-magnetic-field region, combined with a multilayer conductor with an integrated capacitor made with smaller conductor sizes in the high-magnetic-field region. Such a combination may have advantages such as achieving a high total capacitance, achieving a large total cross-sectional area of ​​the conductors in the fixed winding region, and increasing the range of available conductor sizes, which particularly improves the performance of the ICCL. In some embodiments, each conductor in the multilayer conductor may have a single gap or multiple gaps.

[0072] FIG. 13A shows an embodiment of a resonant coil in which a multilayer conductor with an integrated capacitor structure 130 (without a standalone capacitor) can be placed on top of multiple ICCLs (e.g., conductors 2a and 2b separated by a dielectric layer 4), each connected to one or more standalone capacitors (e.g., 6a and 6b). This combination, along with the multilayer conductor with integrated capacitors on two ICCLs, can be placed within a magnetic core, such as a magnetic pot core. In practice, ICCLs in higher magnetic field regions may be made with thicker conductor layers, while the multilayer conductor with integrated capacitors may include thinner conductor layers. The multilayer conductor with integrated capacitor structure may be galvanically isolated from the ICCLs by a dielectric layer 14, which may be formed from a low-loss material. If the bottom conductor layer of the integrated capacitor structure 130 has a gap aligned with the top conductor layer of the multiple ICCLs, the dielectric layer 14 may be formed from a high-loss material. The multilayer conductor with integrated capacitor structure 130 may be inductively and / or capacitively coupled to the multiple ICCLs. In this example, via 5 may connect conductor 2a to standalone capacitor 6a at the bottom of the structure.

[0073] 13B shows an exploded view of an example of a multilayer conductor having an integrated capacitor structure 130 with AC conductors 132 (which may be, for example, thin foil conductors) spaced apart by respective dielectric layers 134. In some embodiments, the conductors 132 may have gaps at alternating 180-degree positions (e.g., front, back, front, etc.) in each conductor layer. However, different types and / or numbers of gaps may be included, and any number of layers may be included. In some embodiments, the dielectric layers 134 may be formed of a low-loss material to serve as the dielectric material of the integrated capacitor between each conductor 132.

[0074] Various aspects of the devices and techniques described herein may be used alone or in combination, or in various configurations not specifically described in the embodiments described in the foregoing description, and therefore are not limited in application to the details and arrangements of components set forth in the foregoing description or illustrated in the drawings. For example, aspects described in one embodiment may be combined in any manner with aspects described in other embodiments.

[0075] The use of ordinary terms such as "first," "second," "third," etc. in a claim to modify a claim element does not, in itself, imply any priority or seniority of one claim element over other claim elements, or any ordering or chronological order in which method actions are performed, but is used solely as a label (but for ordinary use of the term) to distinguish one claim element having a certain name from another element having the same name.

[0076] Terms such as "substantially," "approximately," and "about" indicate that a parameter is within 10%, and optionally less than 5%, of its stated value. Also, the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," "having," "containing," "involving," and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

Claims

1. a plurality of conductors forming a plurality of inductively coupled current loops, a first conductor having a first end and a second end, the first end and the second end being separated by a first gap; a second conductor having a third end and a fourth end, the third end and the fourth end being separated by a second gap; at least one stand-alone capacitor comprising: at least one first capacitor connected to the first end and the second end of the first conductor; and at least one second stand-alone capacitor connected to the third end and the fourth end of the second conductor; a dielectric layer separating the first conductor from the second conductor; A resonant coil comprising:

2. The first gap is substantially aligned with the second gap. The resonance coil according to claim 1 .

3. the first conductor and the second conductor are on respective layers of a printed circuit board; The resonance coil according to claim 1 .

4. the at least one stand-alone capacitor providing a resonant capacitance for the resonant coil; The resonance coil according to claim 1 .

5. the capacitance between the first conductor and the second conductor does not substantially contribute to the resonant capacitance; The resonance coil according to claim 4 .

6. the first conductor and the second conductor are galvanically isolated from each other. The resonance coil according to claim 1 .

7. The first conductor further has a fifth end and a sixth end, the fifth end and the sixth end being spaced apart by a third gap; the second conductor further has a seventh end and an eighth end, the seventh end and the eighth end being spaced apart by a fourth gap; the first gap is substantially aligned with the second gap; the third gap is substantially aligned with the fourth gap; the fifth end of the first conductor is connected to the seventh end of the second conductor to form a galvanic connection; the sixth end of the first conductor is connected to the eighth end of the second conductor to form a galvanic connection. The resonance coil according to claim 1 .

8. Each of two conductors arranged in the stacking direction among the plurality of conductors has two gaps, each of the two conductors includes a stand-alone capacitor connected in series across one of the two gaps; the two conductors are galvanically isolated from each other by the dielectric layer; the two conductors are arranged such that the other of the two gaps is substantially aligned in the stacking direction, and a galvanic connection is formed by connecting the ends of the other gaps of the two conductors. The resonance coil according to claim 1 .

9. each of the first conductor and the second conductor has a C-shape; The resonance coil according to claim 1 .

10. the first conductor and the second conductor are planar; The resonance coil according to claim 1 .

11. each of the first conductor and the second conductor has a toroidal C-shape having an open or closed cross section; The resonance coil according to claim 1 .

12. The first conductor is nested within the second conductor. The resonant coil according to claim 11.

13. the at least one stand-alone capacitor comprises a plurality of stand-alone capacitors having interleaved connections to at least the first conductor and the second conductor. The resonance coil according to claim 1 .

14. a third conductor on an outer side of an edge of the first conductor; the third conductor has the same C-shape as the first conductor; the third conductor has a width smaller than that of the first conductor; The resonance coil according to claim 1 .

15. the first conductor and the second conductor have different thicknesses; The resonance coil according to claim 1 .

16. the first conductor and the second conductor are substantially concentric; The resonance coil according to claim 1 .

17. Combined with a high permeability magnetic material to form a magnetic field; The resonance coil according to claim 1 .

18. the at least one stand-alone capacitor comprises a plurality of stand-alone capacitors having approximately equal capacitances; The resonance coil according to claim 1 .

19. the at least one stand-alone capacitor includes a plurality of stand-alone capacitors having increased capacitance due to an increase in the thickness of a conductor to which a stand-alone capacitor is connected; The resonance coil according to claim 1 .

20. The capacitance increases approximately proportionally with an increase in the thickness of the conductor.

20. The resonant coil of claim 19.

21. the at least one stand-alone capacitor includes a plurality of stand-alone capacitors whose capacitance increases in response to the strength of a magnetic field in which each stand-alone capacitor is placed; The resonance coil according to claim 1 .

22. The semiconductor device according to claim 21, further comprising a multilayer conductor having an integrated capacitor structure disposed on the at least one standalone capacitor; the multilayer conductor has a plurality of AC conductors separated by dielectric layers; the multilayer conductor is inductively coupled to the plurality of inductively coupled current loops of the resonant coil; The resonance coil according to claim 1 .

23. the multilayer conductor having the integrated capacitor structure is disposed in a region of a magnetic field higher than the magnetic field of the plurality of inductively coupled current loops; 23. The resonant coil of claim 22.

24. the first conductor having a plurality of turns; The resonance coil according to claim 1 .

25. a magnetic coupling coefficient between adjacent galvanically isolated current loops of the plurality of inductively coupled current loops exceeds k=0.1, and / or a distance between the adjacent galvanically isolated current loops is less than 1 / 3 of an average diameter of the plurality of inductively coupled current loops. The resonance coil according to claim 1 .

26. the magnetic coupling coefficient is greater than k=0.8 and / or the distance between adjacent galvanically isolated current loops is less than 1 / 10 of the average diameter.

26. The resonant coil of claim 25.

27. the magnetic coupling coefficient is greater than k=0.9 and / or the distance between adjacent galvanically isolated current loops is less than 1 / 15 of the average diameter.

27. The resonant coil of claim 26.

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