Large-area power transmitter for wireless power transfer

Abstract

A method and system for wireless power transmission are provided. The method includes: adapting first and second variable form factor transmitters into at least first and second sets of cross-coupling segments, respectively, the first and second sets of cross-coupling segments being disposed within or near a predetermined wireless power transmission region and spatially offset from one another by a preselected spatial offset that minimizes inductive coupling between the first and second sets of cross-coupling segments; and transmitting radio frequency (RF) power from first and second RF power sources electrically coupled to the first and second sets of cross-coupling segments, respectively, across the predetermined wireless power transmission region via a near electromagnetic field of the variable form factor transmitter, such that a magnetic field associated with the near electromagnetic field rotates in a pattern having a preselected shape.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is a PCT application that claims priority to and the benefit of the filing date of U.S. patent application Ser. No. 16 / 111,889, filed on August 24, 2018, entitled “Large Area Power Transmitter For Wireless Power Transfer,” and Ser. No. 16 / 266,886, filed on February 4, 2018, entitled “Large Area Power Transmitter For Wireless Power Transfer,” both of which are incorporated herein by reference in their entirety. Background Art

[0003] Wireless power transfer is the transmission of electrical energy from a power source to an electrical load without the use of artificial conductors. A wireless power transfer system consists of a transmitter and one or more receiver devices. The transmitter is connected to a power source and converts the power into a time-varying electromagnetic field. The one or more receiver devices receive the power via the electromagnetic field and convert it back into electrical current for use by the electrical load. Summary of the Invention

[0004] In general, in one aspect, the present invention relates to a method for wireless power transmission, comprising: adapting a variable form factor transmitter to be disposed within or near a predetermined wireless power transmission area with at least a plurality of cross-coupling segments; transmitting RF power across the predetermined wireless power transmission area from an RF power source and based at least in part on a characteristic frequency via a near electromagnetic field of the variable form factor transmitter; and wherein radiation losses of the wireless power transmission due to a far electromagnetic field of the variable form factor transmitter are reduced based on oppositely directed magnetic fields induced by adjacent cross-coupling segments of the plurality of cross-coupling segments.

[0005] In another aspect, each of the plurality of cross-coupling segments includes a plurality of sides, and adjacent sides of adjacent cross-coupling segments are configured to conduct current in opposite rotational directions.

[0006] In another aspect, the method further includes providing a plurality of lock-in amplifiers as the RF power source in at least a portion of the plurality of cross-coupling sections.

[0007] In another aspect, a plurality of cross-coupling segments are arranged in or near a predetermined wireless power transmission area according to an endless knot pattern.

[0008] In another aspect, the predetermined wireless power transmission area includes a dimension that exceeds a wavelength corresponding to a characteristic frequency of the variable form factor transmitter.

[0009] In another aspect, the method further comprises: forming one or more of the plurality of cross-coupling segments using a string of distributed capacitors; and connecting the plurality of capacitors in series into the string of distributed capacitors via at least a plurality of wire segments; wherein each of the plurality of capacitors comprises a predetermined capacitance, wherein each of the plurality of wire segments comprises a predetermined segment length and a predetermined inductance per unit length, and wherein the characteristic frequency depends at least on the predetermined capacitance and the predetermined inductance per unit length.

[0010] In another aspect, the method further comprises providing a plurality of receiver devices within a predetermined wireless power transmission area, wherein a portion of the RF power transmitted from the RF power source via the variable form factor transmitter is received by the plurality of receiver devices, and wherein the characteristic frequency is substantially independent of the number or arrangement of the plurality of receiver devices.

[0011] In another aspect, a transmitter for wireless power transmission includes a plurality of cross-coupling segments disposed within or near a predetermined wireless power transmission area and configured to: transmit RF power across the predetermined wireless power transmission area from an RF power source and based at least in part on a characteristic frequency via a near electromagnetic field of the transmitter; and reduce radiation losses of the wireless power transmission due to a far electromagnetic field of the transmitter based on oppositely directed magnetic fields induced by adjacent cross-coupling segments of the plurality of cross-coupling segments.

[0012] In another aspect of the transmitter, each of the plurality of cross-coupling segments includes a plurality of sides, and adjacent sides of adjacent cross-coupling segments are configured to conduct current in opposite rotational directions.

[0013] In another aspect of the transmitter, the RF power supply includes a plurality of lock-in amplifiers disposed in at least a portion of the plurality of cross-coupling sections.

[0014] In another aspect of the transmitter, a plurality of cross-coupling sections are arranged in or near a predetermined wireless power transmission area according to an endless knot pattern.

[0015] In another aspect of the transmitter, the transmitter is a variable form factor transmitter, and the predetermined wireless power transmission area includes a dimension that exceeds a wavelength corresponding to a characteristic frequency of the variable form factor transmitter.

[0016] In another aspect of the transmitter, one or more of the plurality of cross-coupling segments includes a plurality of capacitors and a plurality of wire segments. Each capacitor has a predetermined capacitance. Each wire segment has a predetermined segment length and a predetermined inductance per unit length. The plurality of capacitors are connected in series via at least the plurality of wire segments to form a string of distributed capacitors. The characteristic frequency depends at least on the predetermined capacitance and the predetermined inductance per unit length.

[0017] In another aspect, a system for wireless power transmission includes: a plurality of cross-coupling segments disposed within or near a predetermined wireless power transmission area; and an RF power source coupled to the plurality of cross-coupling segments. The plurality of cross-coupling segments are configured to: transmit RF power from the RF power source and based at least in part on a characteristic frequency across the predetermined wireless power transmission area via near electromagnetic fields of the plurality of cross-coupling segments; and reduce radiation losses in the wireless power transmission caused by far electromagnetic fields of the plurality of cross-coupling segments based on oppositely directed magnetic fields induced by adjacent cross-coupling segments of the plurality of cross-coupling segments.

[0018] In another aspect of the system for wireless power transfer, each of the plurality of cross-coupling segments includes a plurality of sides. Adjacent sides of adjacent cross-coupling segments are configured to conduct current in opposite rotational directions.

[0019] In another aspect of the system for wireless power transfer, an RF power supply includes a plurality of lock-in amplifiers disposed in at least a portion of the plurality of cross-coupling sections.

[0020] In another aspect of the system for wireless power transfer, a plurality of cross-coupling segments are arranged in or near a predetermined wireless power transfer area according to an endless knot pattern.

[0021] In another aspect of the system for wireless power transmission, the predetermined wireless power transmission area includes a dimension exceeding a wavelength corresponding to a characteristic frequency of the plurality of cross-coupling segments.

[0022] In another aspect of the system for wireless power transmission, one or more of the plurality of cross-coupling segments includes a plurality of capacitors and a plurality of wire segments. Each capacitor has a predetermined capacitance. Each wire segment has a predetermined segment length and a predetermined inductance per unit length.

[0023] In another aspect of the system for wireless power transmission, a plurality of capacitors are connected in series via at least a plurality of conductor segments into a string of distributed capacitors. The characteristic frequency depends on at least a predetermined capacitance and a predetermined inductance per unit length.

[0024] In another aspect of the system for wireless power transmission, the system further includes a plurality of receiver devices disposed within a predetermined wireless power transmission area. A portion of the RF power transmitted from the RF power source via the plurality of cross-coupling segments is received by the plurality of receiver devices. The characteristic frequency is substantially independent of the number or arrangement of the plurality of receiver devices.

[0025] In another aspect, a method for wireless power transfer includes:

[0026] Adapting at least a first variable form factor transmitter and a second variable form factor transmitter to be respectively arranged in at least a first set of cross-coupling segments and a second set of cross-coupling segments within or near a predetermined wireless power transmission area, the first set of cross-coupling segments having at least a first terminal and a second terminal, and the second set of cross-coupling segments having at least a first terminal and a second terminal; and

[0027] RF power is transmitted across a predetermined wireless power transfer region via a near electromagnetic field of a first variable form factor transmitter and a second variable form factor transmitter from a first RF power source electrically coupled to first and second terminals of a first set of cross-coupling segments and from a second RF power source electrically coupled to first and second terminals of a second set of cross-coupling segments, wherein the first RF power source and the second RF power source are driven by first and second drive signals, respectively.

[0028] In another aspect of the method for wireless power transfer, the first set of cross-coupling segments and the second set of cross-coupling segments are spatially offset relative to each other by a preselected spatial offset to minimize inductive coupling between the first set of cross-coupling segments and the second set of cross-coupling segments. The first drive signal and the second drive signal are out of phase with each other by a preselected phase shift that ensures that at least a predetermined minimum level of wireless power is available at any location within a predetermined wireless power transfer area.

[0029] In another aspect of the method for wireless power transfer, each cross-coupling segment in the first set of cross-coupling segments includes a plurality of sides. Adjacent sides of adjacent cross-coupling segments in the first set of cross-coupling segments are configured to conduct current in opposite rotational directions.

[0030] In another aspect of the method for wireless power transfer, each cross-coupling segment in the second set of cross-coupling segments includes a plurality of sides. Adjacent sides of adjacent cross-coupling segments in the second set of cross-coupling segments are configured to conduct current in opposite rotational directions.

[0031] In another aspect of the method for wireless power transfer, the preselected spatial offset is approximately equal to half the width of a segment in the first set of cross-coupling segments.

[0032] In another aspect of the method for wireless power transfer, the preselected phase shift amount is approximately 90 degrees.

[0033] In another aspect of the method for wireless power transfer, further comprising:

[0034] disposing a plurality of receiver devices within a predetermined wireless power transmission area;

[0035] wherein a portion of the RF power transmitted from the first RF power source and the second RF power source via the first variable form factor transmitter and the second variable form factor transmitter, respectively, is received by a plurality of receiver devices, and

[0036] Wherein the characteristic frequencies of the first variable form factor transmitter and the second variable form factor transmitter are substantially independent of the number or arrangement of the plurality of receiver devices within the predetermined wireless power transmission area.

[0037] In another aspect, a system for wireless power transfer includes:

[0038] a first set of cross-coupling segments disposed within or near a predetermined wireless power transfer area, the first set of cross-coupling segments having at least a first terminal and a second terminal;

[0039] a second set of cross-coupling segments disposed within or near the predetermined wireless power transfer area, the second set of cross-coupling segments having at least a first terminal and a second terminal; and

[0040] a first radio frequency (RF) power source electrically coupled to the first and second terminals of the first set of cross-coupling segments, the first RF power source electrically coupled to the first set of cross-coupling segments comprising a first variable form factor transmitter operating at a characteristic frequency; and

[0041] a second RF power source electrically coupled to the first and second terminals of the second set of cross-coupling segments, the second RF power source electrically coupled to the second set of cross-coupling segments comprising a second variable form factor transmitter operating at a characteristic frequency. The first set of cross-coupling segments is configured to:

[0042] transferring RF power from the first RF power source across a predetermined wireless power transfer region via the near electromagnetic field of the first set of cross-coupling segments;

[0043] The second set of cross-coupling sections is configured as follows:

[0044] transferring RF power from a second RF power source across a predetermined wireless power transfer region via the near electromagnetic field of the second set of cross-coupling segments; and

[0045] The first RF power supply and the second RF power supply are driven by a first driving signal and a second driving signal respectively.

[0046] In another aspect of the system for wireless power transfer, the first set of cross-coupling segments and the second set of cross-coupling segments are spatially offset relative to each other by a preselected spatial offset to minimize inductive coupling between the first set of cross-coupling segments and the second set of cross-coupling segments. The first drive signal and the second drive signal are out of phase with each other by a preselected phase shift that ensures that at least a predetermined minimum level of wireless power is available at any location within a predetermined wireless power transfer area.

[0047] In another aspect of the system for wireless power transfer, each of the first set of the plurality of cross-coupling segments includes a plurality of sides, and adjacent sides of adjacent cross-coupling segments of the first set are configured to conduct current in opposite rotational directions.

[0048] In another aspect of the system for wireless power transfer, each of the second set of the plurality of cross-coupling segments includes a plurality of sides, and adjacent sides of adjacent cross-coupling segments of the second set are configured to conduct current in opposite rotational directions.

[0049] In another aspect of the system for wireless power transmission, one or more of the first set of cross-coupling segments includes a plurality of capacitors and a plurality of wire segments. Each capacitor has a predetermined capacitance. Each wire segment has a predetermined segment length and a predetermined inductance per unit length. The plurality of capacitors are connected in series via at least the plurality of wire segments to form a string of distributed capacitors. The characteristic frequency depends at least on the predetermined capacitance and the predetermined inductance per unit length.

[0050] In another aspect of the system for wireless power transmission, the system further includes a plurality of receiver devices disposed within a predetermined wireless power transmission area. A portion of RF power transmitted from the first RF power source and the second RF power source via the first and second sets of cross-coupling segments, respectively, is received by the plurality of receiver devices. The characteristic frequency is substantially independent of the number or arrangement of the plurality of receiver devices.

[0051] In another aspect of the system for wireless power transfer, the preselected spatial offset is equal to half the width of a segment in the first set of cross-coupling segments.

[0052] In another aspect of the system for wireless power transfer, the preselected phase shift amount is 90 degrees.

[0053] Other aspects of the invention will become apparent from the following transaction description and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1A 、 1B 1C and 1C show schematic diagrams of example systems with variable form factor transmitters according to one or more embodiments of the present invention.

[0055] Figure 2A 、 2B , 2C, 2D, 2E, 2F, 2G, 2H, 2J, 2K, 2L, 2M, 2N and 2P show various diagrams for illustrating example variable form factor transmitters according to one or more embodiments of the present invention.

[0056] Figure 3A 、 3B , 3C, 3D, and 3E illustrate example characteristics of an example variable form factor transmitter according to one or more embodiments of the present invention.

[0057] Figure 4A and 4B A schematic diagram of an example radio frequency (RF) power supply is shown in accordance with one or more embodiments of the present invention.

[0058] Figure 5A 、 5B 5C, 5D and 5E show schematic diagrams and layout diagrams of example receiver devices according to one or more embodiments of the present invention.

[0059] Figure 6A 、 6B , 6C, 6D, 6E, 6F, 6G, 7A, 7B, 7C, 7D, 7E and 7F show schematic diagrams and layout diagrams of example power transmitters for wireless power transmission according to one or more embodiments of the present invention.

[0060] Figure 8 A method flow chart according to one or more embodiments of the present invention is shown. DETAILED DESCRIPTION

[0061] Now will be described in detail certain embodiments of the present invention with reference to the accompanying drawings. For consistency, like elements in various figures are represented by like reference numerals.

[0062] In the following detailed description of embodiments of the present invention, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. However, it will be apparent to one of ordinary skill in the art that the present invention may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.

[0063] In the following description, in various embodiments of the present invention, any component described with respect to one figure may be equivalent to one or more components of the same name described with respect to any other figure. For the sake of brevity, at least a portion of these components are implicitly identified based on various legends. In addition, the description of these components will not be repeated with respect to each figure. Therefore, each embodiment of the components of each figure is incorporated by reference and is assumed to be optionally present in each other figure with one or more components of the same name. In addition, according to various embodiments of the present invention, any description of the components of the figures should be interpreted as an optional embodiment, which may be a supplement, combination or alternative implementation of the embodiment described with respect to the corresponding components of the same name in any other figure. In the figures, black solid collinear points indicate that there may optionally be additional components similar to the components before and / or after the solid collinear points.

[0064] Throughout the application, ordinal numbers (e.g., first, second, third, etc.) may be used as adjectives for elements (i.e., any nouns in this application). Unless explicitly disclosed, such as by using the terms "before," "after," "single," and other such terms, the use of ordinal numbers does not imply or create any particular order of elements, nor does it limit any element to only a single element. Instead, the use of ordinal numbers is to distinguish elements. For example, a first element is different from a second element, and a first element may contain more than one element and may be after (or before) a second element in the order of the elements.

[0065] In general, embodiments of the present invention provide methods, transmitter devices, and systems for wireless power transmission. In one or more embodiments of the present invention, the method, transmitter device, and system are based on a power transmitter that includes a plurality of capacitors and inductor segments arranged along a path defining a wireless power transmission region. The capacitors are connected in series to form a string of distributed capacitors via at least the inductor segments. In one or more embodiments of the present invention, the string of distributed capacitors is integrated into a laminate material sheet (e.g., including at least a dielectric material) that covers at least the path defining the power transmission region. In one or more embodiments, one or more capacitors and one or more inductor segments are constructed using conductive tape attached to two opposing surfaces of the material sheet. For example, a capacitor may include two conductive tapes attached to two opposing surfaces. Additionally, an inductor segment may include another conductive tape attached to one of the two opposing surfaces. Thus, RF power is transmitted across the wireless power transmission region from a radio frequency (RF) power source and based at least on a characteristic frequency of the string of distributed capacitors via the near electromagnetic field of the string of distributed capacitors. In one or more embodiments of the present invention, the characteristic frequency is within the Industrial, Scientific, and Medical (ISM) radio frequency band defined by the International Telecommunication Union (ITU) Radio Regulations. For example, the characteristic frequency may be within the Class A frequency range specified in Article 5, Footnote 5.138 of the ITU Radio Regulations (ie, 6.765 MHz-6.795 MHz).

[0066] In one or more embodiments of the present invention, the power transmitter has a fixed form factor that is specific to a predetermined wireless power transmission area. In one or more embodiments of the present invention, the power transmitter can be adapted to different form factors (referred to as adapted form factors) to suit different wireless power transmission areas. In such embodiments, the power transmitter is a variable form factor transmitter having a characteristic frequency that is maintained substantially independent of the adapted form factor. For example, as the adapted form factor changes, the characteristic frequency can be maintained within the ISM radio band.

[0067] Figure 1A A schematic diagram of an example system (100) according to one or more embodiments of the present invention is shown. In one or more embodiments, the following may be omitted, repeated, and / or replaced: Figure 1A Therefore, the embodiments of the present invention should not be considered to be limited to Figure 1A Specific settings for the modules shown in .

[0068] like Figure 1AAs shown, the system (100) includes a variable form factor transmitter (102) that receives power from an RF power source (108) for wireless power transmission across a wireless power transmission area (101) with one or more receiver devices (e.g., represented as circular icons labeled with A, B, C, D, E, and F) disposed within the wireless power transmission area (101). Each of these components is described in detail below.

[0069] In one or more embodiments of the present invention, the wireless power transmission area (101) is any three-dimensional (3D) physical space in which one or more receiver devices receive power from a variable form factor transmitter (102). For example, the wireless power transmission area (101) may include a 3D space within a building or vehicle, such as a room, a hallway, a passenger cabin of a car, bus, train, airplane, or spacecraft, or any part of a building or vehicle. In another example, the wireless power transmission area (101) may include an unenclosed 3D space, such as a playground, a road, an amusement park, or any type of venue on the ground, above the ground, or in space far from the earth (e.g., the atmosphere or interstellar space). In yet another example, the wireless power transmission area (101) may include an underground or underwater space, such as a cave, an underwater area near an ocean platform or seabed, etc. In yet another example, the wireless power transmission area (101) may include a combination of the above examples.

[0070] In one or more embodiments of the present invention, the variable form factor transmitter (102) is disposed entirely within the wireless power transmission area (101), overlaps with the wireless power transmission area (101), or is adjacent to the wireless power transmission area (101). In one or more embodiments, at least a portion of the variable form factor transmitter (102) can be inserted into a protective sleeve, embedded in a sheet of material, independently placed in the wireless power transmission area (101), or attached to the wireless power transmission area (101). In one or more embodiments, at least a portion of the variable form factor transmitter (102) can be fixed or movable relative to the wireless power transmission area (101) and / or one or more receiver devices disposed therein (e.g., represented as circular icons labeled with A, B, C, D, E, and F). In one or more embodiments of the present invention, the form factor of the variable form factor transmitter (102) is adapted according to geometric constraints imposed by the wireless power transmission area (101). For example, the variable form factor transmitter (102) can be made of a flexible material so that the form factor of the variable form factor transmitter (102) is changed by the user to fit the physical shape of a room, corridor, cabin, playground, road, amusement park, field, cave, underwater area, etc. of the wireless power transmission area (101). In this context, the form factor of the variable form factor transmitter (102) is based on the wireless power transmission area (101). For example, the form factor of the variable form factor transmitter (102) can include 3D parts, such as curved surfaces, spiral curves, etc.

[0071] In one or more embodiments of the present invention, the receiver devices (A) to (F) may be of the same type or different types used by one or more users (e.g., individuals). In one or more embodiments, one or more of the receiver devices (A) to (F) are set at a user-specified location throughout the wireless power transmission area (101) and are stationary during wireless power transmission. In one or more embodiments, one or more of the receiver devices (A) to (F) have a size smaller than the size of the wireless power transmission area (101). In one or more embodiments, one or more of the receiver devices (A) to (F) have a size comparable to or larger than the size of the wireless power transmission area (101). For example, the receiver device (A) may be a lighting device placed by a user on the ceiling of a room or hallway. In one or more embodiments, one or more of the receiver devices (A) to (F) are carried by the respective user, who occasionally moves around throughout the wireless power transmission area (101) during wireless power transmission. Based on the properties of the near electromagnetic field of the variable form factor transmitter (102), power of the near electromagnetic field that is not received by any receiver device is returned to the variable form factor transmitter (102) and the RF power source (108). This is in contrast to remote electromagnetic fields, where radiating power results in energy loss, which is not productive for wireless power transfer. Figure 5A 、 5B , 5C, 5D and 5E describe examples of receiver device (A), receiver device (B), receiver device (C), receiver device (D), receiver device (E) and receiver device (F).

[0072] In one or more embodiments of the present invention, a variable form factor transmitter (102) includes a series of distributed capacitors. Specifically, the series of distributed capacitors includes a plurality of capacitor-wire segments connected in series to conduct a radio frequency (RF) current (105) generated by a power source (108). The RF current (105) induces a magnetic field (e.g., magnetic field (106)) present throughout a wireless power transmission region (101). In one or more embodiments, the series of distributed capacitors is arranged along a path such that the magnetic field throughout the wireless power transmission region (101) exceeds a threshold value based on the power requirements of a receiver device. In this context, the path is based on the wireless power transmission region (101). In one or more embodiments, the RF current (105) enters / exits the wire at terminal A (204a) and terminal B (204b). In one or more embodiments, additional intermediate components (not shown) may also be inserted into the series of capacitor-wire segments or between the series of capacitor-wire segments and one or more terminals (e.g., terminal A (204a), terminal B (204b)) without interfering with the operation of the variable form factor transmitter (102).

[0073] In one or more embodiments, each capacitor-wire segment includes a capacitor (e.g., capacitor (103)) connected to a wire segment (e.g., wire segment (104)). In one or more embodiments, each capacitor (e.g., capacitor (103)) in the variable form factor transmitter (102) has the same nominal capacitance value as any other capacitor therein, which is determined before the variable form factor transmitter (102) is set up in the wireless power transmission area (101). For example, the capacitors (e.g., capacitor (103)) in the variable form factor transmitter (102) can be installed in the factory before the user uses the variable form factor transmitter (102) to wirelessly provide power within the wireless power transmission area (101). The capacitors (e.g., capacitor (103)) can be of a suitable type, such as a ceramic capacitor, a paper film capacitor, an electrolytic capacitor, a polymer capacitor, a silver mica capacitor, etc. In one or more embodiments, one or more capacitors can include two aluminum or other metal sheets, foils, or films separated by an aluminum or other metal oxide layer. As is typical during factory manufacturing, the capacitance values ​​of all capacitors (eg, capacitor (103)) in a variable form factor transmitter (102) may vary within a certain range (referred to as the capacitance range), eg, due to manufacturing tolerances.

[0074] In one or more embodiments, each capacitor-wire segment comprises a wire segment having a predetermined segment length and a predetermined inductance per unit length. For example, the wire segments (e.g., wire segments (104)) in the variable form factor transmitter (102) can be installed in a factory before a user uses the variable form factor transmitter (102) to wirelessly provide power within the wireless power transmission area (101). The wire segments (e.g., wire segments (104)) can be of a suitable type, such as insulated or non-insulated wire, sheet, foil, or film, made of copper, aluminum, or other suitable metal and / or alloy material. In one or more embodiments, one or more wire segments (e.g., wire segments (104)) are flexible or pliable so that a user can bend, stretch, or otherwise change the shape of one or more wire segments. As is typical in a factory manufacturing process, the length and inductance values ​​of each and all wire segments (e.g., wire segments (104)) in the variable form factor transmitter (102) can vary within a certain range (referred to as a length range and an inductance range), for example, due to manufacturing tolerances.

[0075] In one or more embodiments of the present invention, a capacitor (e.g., capacitor (103)) in a variable form factor transmitter (102) reduces stray electric fields and the resulting induced voltage of a wire segment (e.g., wire segment (104)) by limiting the electric field. Thus, the capacitor (e.g., capacitor (103)) in the variable form factor transmitter (102) reduces the proportion of energy stored in the stray capacitance of the wire segment (e.g., wire segment (104)) relative to the total energy in the system (100). The reduction in induced voltage and stored energy associated with stray capacitance reduces losses due to environmental interactions and improves user safety.

[0076] In one or more embodiments of the present invention, a variable form factor transmitter (102) is associated with a characteristic frequency based on at least a predetermined capacitance, a predetermined segment length, and a predetermined inductance per unit length. Figure 2A 、 2B , 2D, 2E, 3A, 3B, 3C, 3D and 3E describe the characteristic frequencies of the variable shape factor transmitter (102). Throughout this document, the terms "characteristic frequency" and "resonant frequency" may be used interchangeably depending on the context.

[0077] In one or more embodiments, instead of a direct connection to the power source (108), the variable form factor transmitter (102) receives power from the power source (108) using inductive coupling via a drive loop (109a). Figure 1B A schematic diagram of an example system (100) in an inductively coupled power configuration is shown. Figure 1C Details of receiving power via the drive circuit (109a) are described.

[0078] Figure 1C Shown above Figure 1B In one or more embodiments, the power supply of the drive circuit (109a) may be omitted, repeated and / or replaced. Figure 1C Therefore, the embodiments of the present invention should not be considered to be limited to Figure 1C Specific settings for the modules shown in .

[0079] like Figure 1CAs shown, the drive loop (109a) includes one or more wire loops (e.g., having an inductance L1) that are coupled to the power supply (108) via a balun (108a). The balun (108a) includes a tuning capacitor A (109d) (e.g., having a variable capacitance C1), a tuning capacitor B (109e) (e.g., having a variable capacitance C2), and a coaxial cable (109c) (e.g., coiled around a ferrite core (109b) and having an inductance L2). Specifically, the drive loop (109a) is placed at a distance (110) from the variable form factor transmitter (102), so that the power supply (108) supplies power to the variable form factor transmitter (102) via electromagnetic coupling across the distance (110). In one or more embodiments, tuning capacitor B (109e) is tuned to resonate with the inductance L2 of the ferrite core (109b) to form a parallel resonant LC circuit that applies a high impedance between the two opposite ends of the coaxial cable (109c). In addition, tuning capacitor A (109d) is used to tune the resonant frequency of the drive loop (109a) to match the frequency of the RF power supply (108). The distance (110) between the drive loop (109a) and the variable shape factor transmitter (102) can be adjusted to match the apparent input impedance of the variable shape factor transmitter (102) with the impedance of the coaxial cable (109c) and the output impedance of the RF power supply (108).

[0080] Figure 2A A schematic diagram of a parallel line transmission line (201) according to one or more embodiments of the present invention is shown. In one or more embodiments, the Figure 2A Therefore, the embodiments of the present invention should not be considered to be limited to Figure 2A Specific settings for the modules shown in .

[0081] like Figure 2A As shown, sinusoidal icons (201a) and (201b) represent electromagnetic waves propagating along a parallel line transmission line (201). The parallel line transmission line (201) is composed of two parallel lines (201d), each line having a conductor segment connected by a capacitor, where s represents the length of each conductor segment, C represents the capacitance of each capacitor, and q represents the displacement of charge along the parallel line transmission line (201). RF current (e.g., Figure 1AIn the case of the current (105) shown in FIG, each of the two parallel lines (201d) is also referred to as a conductor throughout the document. The distance between the sinusoidal icons (201a) and (201b) corresponds to the length of the parallel line transmission line (201), and the spacing between the two series of parallel capacitors corresponds to the width of the parallel line transmission line (201). Although the length of the parallel line transmission line (201) can be comparable to the length of other dimensions of the wireless power transmission area (101), the width of the parallel line transmission line (201) can be in the range of less than 1 cm to the width or other dimensions of the wireless power transmission area (101). In one or more embodiments, the parallel line transmission line (201) corresponds to the above Figure 1A In other words, Figure 1A The two sections of a string of distributed capacitors depicted in FIG can be arranged parallel to each other. In general, the amount of charge q displaced along the parallel line transmission line (201) is a function of position along the parallel line transmission line (201) and time. The corresponding charge density (i.e., the amount of charge per unit length) ρ λ The sum of the current I is given by the following equation (1) for the parallel line transmission line (201). In equation (1), x and t represent the position and time along the parallel line transmission line (201), respectively.

[0082]

[0083] Table 1 shows additional definitions of variables used in equations throughout this document.

[0084] Table 1

[0085] c = capacitance per unit length

[0086] l = inductance per unit length

[0087] C = capacitance of each connected capacitor

[0088] s = length of each segment

[0089] q = charge displacement

[0090] ρ λ = Charge density

[0091] λ = wavelength in free space

[0092] I = current

[0093] U j = Energy stored in two connected capacitors

[0094] u E =Electrical energy stored per unit length

[0095] u B = magnetic energy stored per unit length

[0096] v = asymptotic velocity

[0097] ω0 = cutoff frequency

[0098] v p = phase velocity

[0099] v g = Group velocity

[0100] The electrical energy U stored in a pair of adjacent capacitors (eg, capacitor pair (201c)) in the parallel line transmission line (201) j It is given by the following equation (2).

[0101]

[0102] In the case where s is substantially smaller than the spatial variation of q, the stored energy U j = s divided by the segment length s can be considered as the energy density stored in the capacitor C along the parallel line transmission line (201). Assume that c represents the stray capacitance per unit length between two parallel lines of the parallel line transmission line (201). The total electrical energy u stored per unit length along the parallel line transmission line (201) is E It is given by the following equation (3).

[0103]

[0104] The total magnetic energy u stored per unit length along the parallel wire transmission line (201) B It is given by the following equation (4).

[0105]

[0106] Therefore, the Lagrangian of the parallel line transmission line (201) is given by the following equation (5).

[0107]

[0108] The generalized momentum π, the Euler-Lagrange equation of motion, and the wave equation for the parallel line transmission line (201) are given by equations (6), (7), and (8) below.

[0109]

[0110]

[0111]

[0112] Based on the wave equation Equation (8), the dispersion relation of the parallel line transmission line (201) is given by the following Equations (9a), (9b) and (9c).

[0113]

[0114]

[0115]

[0116] In equation (9a), equation (9b), and equation (9c), ω represents the angular frequency, k represents the wave number, v represents the asymptotic wave velocity as defined in equation (9a), and ω0 represents the cutoff angular frequency as defined in equation (9b). In particular, the cutoff angular frequency ω0 is independent of the length of the parallel line transmission line (201) and varies logarithmically with the width of the parallel line transmission line (201). In one or more embodiments, one or more wire segments with associated capacitors of the parallel line transmission line (201) are detachable. Thus, the parallel line transmission line (201) can be reconfigured by a user without substantially changing ω0 to change the total length according to the size of the wireless power transmission area (101).

[0117] Based on equation (9c), Figure 3A A graph of angular frequency ω versus wave number k is shown to illustrate the dispersion relation of the parallel line transmission line (201). In addition, the phase velocity v p and group velocity v g This is given in equations (10a) and (10b) below.

[0118]

[0119]

[0120] Note that as the wave number k asymptotically approaches 0, the phase velocity v p Asymptotically approaches infinity, the group velocity v g asymptotically approaches 0, and the angular frequency ω asymptotically approaches ω0.

[0121] Figure 2B A schematic diagram of a parallel line transmission line (201) driven by an RF power source (108) according to one or more embodiments of the present invention is shown. In one or more embodiments, the Figure 2B Therefore, the embodiments of the present invention should not be considered to be limited to Figure 2B Specific settings for the modules shown in .

[0122] like Figure 2BAs shown, a parallel line transmission line (201) is driven by an RF power source (108) connected via terminal A (204a) and terminal B (204b). In addition, the parallel line transmission line (201) is terminated by a conductive connection (202) and operates at a characteristic frequency ω0. In one or more embodiments of the present invention, the conductive connection (202) can be replaced by a variable capacitor or other electronic component, which can be used to fine-tune the characteristic frequency of the parallel line transmission line (201).

[0123] In one or more embodiments of the present invention, Figure 2B The configuration of the parallel line transmission line (201) shown in the above Figure 1A The variable shape factor transmitter (102) shown in FIG is approximated. Similar to Figure 1A , receiver devices (e.g., represented as circular icons labeled with A, B, C, D, E, and F) surround Figure 2B The parallel line transmission line (201) shown in FIG is arranged. This approximation is particularly applicable to the case where the wireless power transmission area (101) has an elongated shape and a string of distributed capacitors of the variable shape factor transmitter (102) is arranged as a pair of parallel lines according to the elongated shape of the wireless power transmission area (101). As described below, the characteristic frequency of the variable shape factor transmitter (102) corresponds to the above reference frequency. Figure 2A ω0 is described and is substantially independent of the length of the parallel line transmission line (201) and varies logarithmically with the width of the parallel line transmission line (201).

[0124] exist Figure 2BIn the configuration shown, a standing wave along the parallel line transmission line (201) as excited by the RF power source (108) has an infinite phase velocity. Therefore, the voltage and current along the parallel line transmission line (201) are all in phase at different locations along the parallel line transmission line (201). In other words, regardless of the physical length of the parallel line transmission line (201), the effective electrical length of the parallel line transmission line (201) is equal to zero. In the absence of energy loss in the parallel line transmission line (201), regardless of the physical length of the parallel line transmission line (201), the input impedance of the parallel line transmission line (201) presented to the RF power source (108) is equal to zero. In other words, the parallel line transmission line (201) is equivalent to an RLC circuit (not shown) resonating at ω0, regardless of whether the physical length of the parallel line transmission line (201) is much shorter or much longer than the free space wavelength of the driving frequency, i.e., ω0 (e.g., based on the transmission medium of the wireless power transmission area (101)). Thus, a parallel line transmission line (201) driven by an RF power source (108) and terminated by a conductive connection (202) can be used as a resonant power source for wireless power transmission to induce resonance in a receiver device placed near the parallel line transmission line (201). In particular, the resonant receiver device couples to the electric field and / or magnetic field generated by the standing wave of the parallel line transmission line (201) and receives power from the electric field and / or magnetic field.

[0125] In one or more embodiments, a resonant receiver device receives power from a near electromagnetic field of a parallel wire transmission line (201). Even if the physical length of the parallel wire transmission line (201) is much longer than the free space wavelength of the driving frequency (e.g., based on the transmission medium of the wireless power transmission region (101)), the power provided by the RF power source (108) is substantially retained in the parallel wire transmission line (201) for transmission to the nearby resonant receiver device without being lost to far-field radiation. The quality factor of the parallel wire transmission line due to radiation loss depends only on the wire spacing and wire radius, not on the length.

[0126] Figure 2C A variation of a parallel line transmission line (201) with distributed capacitance is shown in which one conductor line forms a conductive shield (203) around another conductor line, hereinafter referred to as a shielded transmission line (201a). For example, the conductive shield (203) may be substantially cylindrical. Figure 2C The working principle of the shielded transmission line (201a) shown above is the same as that of Figure 2B The parallel line transmission line (201) shown is identical except that the distributed capacitance is placed only on the center conductor. In some configurations, the center conductor may not be concentric with the outer conductor (i.e., conductive shield 203). Additionally, the cross-sections of the center conductor and outer conductor (i.e., conductive shield 203) may not be circular.

[0127] In one or more embodiments of the present invention, Figure 2C The configuration of the shielded transmission line (201a) shown in the above Figure 1A The variable shape factor transmitter (102) shown in FIG is approximated. Similar to Figure 1A , receiver devices (e.g., represented as circular icons labeled with A, B, C, D, E, and F) surround Figure 2C This approximation is particularly applicable to the case where the wireless power transmission area (101) corresponds to the interior space of a conductive housing (such as a metal pipe, the fuselage of an aircraft or space shuttle, etc.). Figure 2C As shown, the characteristic frequency of the variable shape factor transmitter (102) corresponds to the above reference Figure 2A and 2B ω0 is described and is substantially independent of the length of the conductive shield (203) and varies logarithmically with the diameter of the conductive shield (203). Figure 2C The characteristic frequency of the shielded transmission line (201a) shown in is given by equation (11). Note that this differs from equation (9b) by a factor of Because there is only one conductor line including the distributed capacitors.

[0128]

[0129] Figure 3B shows a parallel wire transmission line of arbitrary length (e.g. Figure 2A or Figure 2B Figure 1 shows a graph of the quality factor Q of a 14AWG copper wire driven at 6.78 MHz as a function of the spacing d (between the two wires) divided by the free-space wavelength λ. For wire spacings that are large relative to the free-space wavelength, Q is suppressed due to radiation losses. However, for wire spacings that are small compared to the free-space wavelength, radiation is suppressed and the losses are dominated by ohmic losses in the copper wire.

[0130] Note that the shielded transmission line (201) has no radiation losses due to the fact that the conductive shield (203) completely surrounds the internal electromagnetic field.

[0131] In contrast, although the wire loop driven by the RF power source (108) (see below Figure 2D Description) can also transfer power to a nearby resonant receiver device, but as the size of the wire loop increases to approach or exceed the free-space wavelength of the drive frequency, the efficiency of the power transfer decreases due to far-field radiation. Figure 3CA graph shows the quality factor, Q, of a circular loop consisting of 14AWG copper wire driven at 6.78 MHz as a function of the loop radius, a, divided by the free-space wavelength, λ. Note that Q becomes lower, and therefore the efficiency of wireless power transfer is suppressed, as the loop radius becomes larger relative to the free-space wavelength.

[0132] Figure 2D A schematic diagram of a wire loop (204) having distributed capacitors and driven by an RF power source (108) according to one or more embodiments of the present invention is shown. In one or more embodiments, the following may be omitted, repeated, and / or replaced: Figure 2D Therefore, the embodiments of the present invention should not be considered to be limited to Figure 2D Specific settings for the modules shown in .

[0133] In one or more embodiments, the wire loop (204) has a circular loop radius a and a wire radius (corresponding to the gauge of the wire) b (not shown), and is composed of a wire segment of length s connected by a plurality of capacitors C. In one or more embodiments of the present invention, Figure 2D The configuration of the wire loop (204) shown in FIG. Figure 1A The invention relates to a variable form factor transmitter (102) as depicted in FIG. This approximation is particularly suitable when the specific shape of the wireless power transmission area (101) matches the circular form factor of the variable form factor transmitter (102). As described below, the characteristic frequency of the variable form factor transmitter (102) corresponds to the resonant frequency ω0 of the wire loop (204) and is substantially independent of the width and / or length (i.e., form factor) of the wire loop (204).

[0134] The inductance L and the total capacitance C of the conductor loop (204) tot The resonant angular frequency ω0 is given by the following equations (12a), (12b), and (12c).

[0135]

[0136]

[0137]

[0138] In equations (12a), (12b), and (12c), N represents the number of wire segments or capacitors C in the wire loop (204), and μ represents the electromagnetic permeability of the transmission medium in the wireless power transmission area (101). In one or more embodiments, the resonant angular frequency ω0 depends only weakly on the radius a of the wire loop (204) or the wire radius b. In one or more embodiments, one or more wire segments with associated capacitors of the wire loop (204) are detachable. Thus, depending on the size of the wireless power transmission area (101), a user can reconfigure the wire loop (204) to change the loop radius a without substantially changing the resonant angular frequency ω0.

[0139] With the above Figure 2A Unlike the parallel wire transmission line (201) shown in FIG, when the radius a becomes comparable to or exceeds the free space wavelength of the driving frequency, i.e., ω0 (e.g., based on the transmission medium of the wireless power transmission region (101)), the wire loop (204) becomes an effective far-field radiator. The radiation resistance (i.e., the effective series resistance due to far-field radiation) R of a closed conductive loop carrying a uniform current is rad is given by a double integral over the wire path as shown in equation (13a) below.

[0140]

[0141]

[0142]

[0143] In equation (13a), based on the transmission medium of the wireless power transmission area (101), is the impedance of free space, and k is the free space wave number. Based on equation (13a) applied to the wire loop (204), Figure 3D A graph showing the radiation resistance divided by the impedance of free space as a function of radius divided by wavelength is shown. Figure 3D It can be seen that the radiation resistance has the asymptotic form for large and small loop radii given in equation (14) below.

[0144]

[0145] The quality factor Q of the loop due to radiation is equal to the inductive reactance ω0L divided by the total series resistance R (which includes the radiation resistance R rad As the radiation resistance increases, the quality factor decreases, resulting in a decrease in the efficiency of wireless power transmission.

[0146] for Figure 2DFor the circular wire loop (204) shown in FIG, equation (12c) applies, Where a is the loop radius and b is the wire radius. Figure 2B For the parallel line transmission line (201) shown in FIG, equation (9b) applies and can be shown as where d is the width of the parallel wire transmission line and b is the wire radius. If ln(a / b)≈ln(d / b), then the characteristic frequency ω0 has similar values ​​for both the circular loop and the parallel wire configurations. In this way, a single variable form factor transmitter (102) can be manufactured based on a user-adapted elongated form factor or circular form factor for use in both an elongated shaped service area and a circular service area. In other words, based on the wire diameter b used to manufacture the variable form factor transmitter (102), the user can select the loop radius a and the parallel wire transmission line width d such that ln(a / b)≈ln(d / b). In this way, a single variable form factor transmitter manufactured at a factory can be configured to Figure 2B The parallel line shape factor depicted in or Figure 2D to power the same set of receiving devices tuned to a specific resonant frequency ω0.

[0147] Figure 2E A schematic diagram of a rectangular loop (206) having distributed capacitors and driven by an RF power source (108) according to one or more embodiments of the present invention is shown. In one or more embodiments of the present invention, the configuration of the rectangular loop (206) is similar to the above Figure 1A The variable shape factor transmitter (102) depicted in FIG is approximated. Similar to Figure 1A , receiver devices (e.g., represented as circular icons labeled with A, B, C, D, E, and F) surround Figure 2E The rectangular loop (206) shown in FIG. For example, the rectangular loop (206) may correspond to Figure 2B The parallel wire transmission line (201) shown in FIG has been adapted by the user to fit into a rectangular wireless power transmission area. In another example, the rectangular loop (206) may correspond to Figure 2D The wire loop (204) shown in FIG has been adapted by the user to fit within a rectangular wireless power transmission area. Figure 2E As shown, the rectangular loop (206) is driven by the RF power supply (108) using a transformer coupling scheme. Specifically, the transformer (206a) includes a capacitor C2 connected in parallel with the primary coil L1 and a capacitor C1 connected in parallel with the secondary coil L1. In addition, Figure 2BThe conductive connection (202) shown in FIG is replaced by capacitor C2. The capacitance values ​​of capacitors C1, C2, and C3 can be adjusted at the factory and / or by the user for impedance matching between the power supply (108) and the rectangular loop (206) and for tuning the resonant frequency of the rectangular loop (206).

[0148] Figure 2F A schematic diagram of connecting a power supply (108) using a capacitive coupling scheme is shown. Specifically, the power supply (108) is connected to a distributed capacitor string (207) via a coaxial cable (208) and a twisted pair (209) at opposite terminals of a tuning capacitor C1. The value of the tuning capacitor C1 can be adjusted in the factory or by the user to provide appropriate impedance matching for the RF power supply (108) and the coaxial cable (208). The shield of the coaxial cable (208) is maintained at ground potential by attaching the shield to a voltage node of the distributed capacitor string (207).

[0149] In one or more embodiments, the distributed capacitor string (207) may correspond to Figure 2B and 2C A portion of the parallel line transmission line (201) shown in Figure 2D a portion of the wire loop (204) shown in FIG. Figure 2E A portion of a rectangular loop (206) is shown in FIG. The magnitude of a voltage (210) induced by a power source (108) relative to ground is shown as a function of position along a distributed capacitor string (207).

[0150] Figure 2G A schematic diagram showing a method for connecting a power source (108) to a variable form factor transmitter using an alternative capacitive coupling scheme is shown. Figure 2G As shown, a resonant balun (211) is used to connect the power supply (108) to the tuning capacitor C1.

[0151] Figure 3E is a rectangular loop (for example, above Figure 2E A graph of the inductance as a function of the aspect ratio (expressed as width / half perimeter) of a rectangular loop (206) shown in FIG. 2 ) made from 83 feet of 14AWG wire and driven at 6.78 MHz. Figure 3E The rectangular loops of aspect ratio ranges shown in represent various shapes, Figure 2DThe wire loop (204) shown in FIG can be adapted by the user to suit any wireless power transmission area. The graph shows the inductance of a rectangular loop when the perimeter (i.e., the circumference corresponding to the wire loop (204)) remains fixed but the aspect ratio varies. As can be seen from the graph, when the aspect ratio varies within a wide range between 0.05 and 0.95, the change in inductance is less than 20%. Therefore, when adapted to a rectangular loop within a wide range of aspect ratios, the characteristic frequency of the wire loop (204) changes by less than 10%. This demonstrates that the resonant frequency of the loop with distributed capacitance is relatively insensitive to changes in the adapted form factor.

[0152] Return Reference Figure 1A In one or more embodiments of the present invention, the system (100) provides wireless power transmission across a wireless power transmission area (101) based on the ISM band. Figure 2A 、 2B In the case of the parallel line transmission line (201) approximation shown in FIG2C, the conductor segment length s, the inductance per unit length l, and the value of the capacitor C can be selected in the factory based on equation (9b) to keep the resonant angular frequency ω0 of the parallel line transmission line (201) equal to the angular frequency of the RF power supply, which can be within the Class A frequency range defined in Article 5, Footnote 5.138 of the ITU Radio Regulations (i.e., 6.765 MHz-6.795 MHz).

[0153] In by Figure 2D In the case of a variable form factor transmitter (102) approximated by the wire loop (204) shown in FIG, the value of the wire segment length s and capacitor C can be selected at the factory based on equation (12c) to maintain the resonant angular frequency ω0 of the wire loop (204) equal to the angular frequency of the RF power supply, which can be within the Class A frequency range defined in ITU Radio Regulations Article 5, Footnote 5.138 (i.e., 6.765 MHz-6.795 MHz).

[0154] In one or more embodiments of the present invention, the above-mentioned manufacturing tolerances are controlled so that the resulting capacitance range, length range, and inductance range do not cause the resonant angular frequency ω0 to deviate from the Class A frequency range (i.e., 6.765 MHz-6.795 MHz). In addition, for both of the above cases, there are approximation errors due to the physical difference between the user-adapted form factor of the variable form factor transmitter (102) and the simplified form factor of the parallel wire transmission line (201) or the wire loop (204). In one or more embodiments of the present invention, to compensate for the above-mentioned manufacturing tolerances and approximation errors, the input impedance and characteristic frequency of the variable form factor transmitter (102) can be adjusted in the factory and by the user.

[0155] Further targeting the above Figure 1A Discussion of Figure 2H shows a schematic diagram of equivalent circuit A (205a) and equivalent circuit B (205b) of a variable shape factor transmitter (102). To achieve optimal power transfer from a power source (108), the input impedance of the variable shape factor transmitter (102) is matched to the output impedance of the power source (108) (represented by resistor R L . The resistor R is the effective series resistance, representing all loss sources of the variable shape factor transmitter (102) (e.g., ohmic losses, radiation losses, dielectric losses, etc.). The variable capacitor C1 determines the apparent input impedance of the variable shape factor transmitter (102) at its resonant frequency, while the variable capacitor C2 sets the resonant frequency.

[0156] Equivalent circuit B (205b) corresponds to a simplified form of equivalent circuit A (205a), where C2, C3, and L have been combined into a single reactance χ. When C1 has a value given by equation (15), the input impedance of the variable shape factor transmitter (102) is equal to R L .

[0157]

[0158] For the case of R L < R, the transformer coupling scheme shown in Figure 2E can be used. For the case of R L ≥ R, the capacitive coupling scheme shown in Figure 2F can be used.

[0159] Figure 2J shows an example construction of a variable shape factor transmitter (102) depicted based on a legend (221) according to one or more embodiments. In one or more embodiments, one or more of the modules and components shown in Figure 2J can be omitted, repeated, and / or replaced. Therefore, the embodiments of the present invention should not be considered limited to the specific arrangement of the modules shown in Figure 2J .

[0160] As shown in Figure 2J , distributed capacitor string A (210a) and distributed capacitor string B (210b) are two example constructions of the variable shape factor transmitter (102) depicted above in FIGS. 1.1 and 1.2. Therefore, respectively in the above Figure 2D and 2EThe wire loop (204) and rectangular loop (206) depicted in the drawings can be based on a distributed capacitor string A (210a), a distributed capacitor string B (210b), or a combination thereof. In particular, the distributed capacitor string A (210a) and the distributed capacitor string B (210b) illustrate two example configurations corresponding to a cross-sectional view of the wire loop (204) or the rectangular loop (206). Specifically, the cross-sectional view includes a cross-section of a continuous capacitor and wire segment in the wire loop (204) or the rectangular loop (206).

[0161] Distributed capacitor string A (210a) includes capacitors formed from conductive ribbons (230a), (230b), (230c), (230d), (230e), (230f), etc., attached to two opposing surfaces (i.e., surface A (220a) and surface B (220b)) of a sheet of dielectric material. Specifically, the sheet has a three-dimensional (3D) form factor, with a majority (e.g., greater than 90%) of its surface area occupied by the two opposing surfaces. In other words, the thickness of the sheet (i.e., the distance between the two opposing surfaces) is significantly smaller than each dimension of the two opposing surfaces. In this context, the 3D form factor of the sheet can be expressed as a two-dimensional (2D) form factor, with the thickness being along the third dimension perpendicular to the surfaces (e.g., surface A (220a) and surface B (220b)) of the 2D form factor. The conductive ribbon is a sheet of conductive material attached to the sheet of dielectric material and having an area significantly smaller (e.g., less than 10%) than the area of ​​the sheet of dielectric material. A distributed capacitor string A (210a) is depicted in a cross-sectional view showing a cross section of a conductive tape and a sheet of dielectric material. In particular, the cross-sectional view is cut along a third dimension across surface A (220a) and surface B (220b) to illustrate the thickness of the conductive tape and the sheet of dielectric material.

[0162] In one or more embodiments, one or more conductive strips (230a), (230b), (230c), (230d), (230e), (230f), etc. are printed on surface A (220a) and / or surface B (220b) using conductive ink, paste, paint, or other conductive coating materials. In one or more embodiments, one or more conductive strips (230a), (230b), (230c), (230d), (230e), (230f), etc. are formed by selectively etching one or more conductive films laminated with a dielectric material sheet. For example, the conductive film and the dielectric material sheet can be laminated together using heat, pressure, adhesives, welding, or other suitable methods.

[0163] For example, capacitor (211) includes an overlapping portion of conductive tape (230a) and conductive tape (230e) attached to surface A (220a) and surface B (220b), respectively, which are separated by a thickness d of a dielectric material sheet. The overlapping portion of conductive tape (230a) and conductive tape (230e) forms two electrodes in a parallel plate configuration of capacitor (211). Similarly, capacitor (213) includes an overlapping portion of conductive tape (230b) and conductive tape (230e) attached to surface A (220a) and surface B (220b), respectively, which are separated by a thickness d of a dielectric material sheet. The overlapping portion of conductive tape (230b) and conductive tape (230e) forms two electrodes in a parallel plate configuration of capacitor (213). The overlapping portion of two adjacent conductive tapes is referred to as an overlapping region having a distance x. Furthermore, each of the conductive strips (230a), (230b), (230c), (230d), (230e), (230f), etc., functions as an inductor segment connecting two adjacent capacitors in the distributed capacitor string A (210a). For example, the conductive strip (230e) functions as or otherwise implements an inductor segment (212) to connect capacitor (211) and capacitor (213) in series. Thus, capacitor (211) and inductor segment (212) form one of the plurality of capacitor-conductor segments of the distributed capacitor string A (210a). Similarly, capacitor (213) and inductor segment (214) form another of the plurality of capacitor-conductor segments of the distributed capacitor string A (210a). In the distributed capacitor string A (210a), the surface of the dielectric material sheet to which the inductor segment is attached alternates between surface A (210a) and surface B (210b). For example, the inductor segment (212) and one electrode of the capacitor (213) are integrated into a single conductive strip (230e) attached to surface A (210a), while the inductor segment (214) and the other electrode of the capacitor (213) are integrated into a single conductive strip (230b) attached to the opposite surface B (210b). In this context, each capacitor-wire segment shown in the distributed capacitor string A (210a) is a first type of integrated capacitor-wire segment. As used herein, an integrated capacitor-wire segment is a series-connected capacitor and inductor segment, wherein the inductor segment and one electrode of the capacitor are integrated into a single conductive strip.

[0164] Further Figure 2JAs shown, distributed capacitor string B (210b) includes a capacitor composed of conductive ribbons (230g), (230h), (230j), (230k), (230m), (230n), (230p), etc. attached to two opposing surfaces of a dielectric material sheet (i.e., surface C (220c) and surface D (220d)). Similar to distributed capacitor string A (210a), distributed capacitor string B (210b) can be constructed by printing, lamination, etching, or a combination thereof. For example, capacitor (215) includes overlapping portions of conductive ribbon (230g) and conductive ribbon (230m) attached to surface C (220c) and surface D (220d), respectively, which are separated by a thickness d of the dielectric material sheet. The overlapping portions of conductive ribbon (230g) and conductive ribbon (230m) form two electrodes in a parallel plate configuration of capacitor (215). Capacitor (216) includes overlapping portions of conductive ribbon (230h) and conductive ribbon (230m) attached to surface C (220c) and surface D (220d), respectively, separated by a thickness d of a dielectric material sheet. The overlapping portions of conductive ribbon (230h) and conductive ribbon (230m) form two electrodes in a parallel plate configuration of capacitor (216). Capacitor (215) and capacitor (216) are connected in series at conductive ribbon (230m) to form a combined capacitor (222) that is connected between conductive ribbon (230g) and conductive ribbon (230h). Similarly, a combined capacitor (223) comprising two series-connected capacitors is connected between conductive ribbon (230h) and conductive ribbon (230j). In addition, each conductive ribbon (230g), (230h), (230j), etc., serves as an inductive segment connecting two adjacent combined capacitors in distributed capacitor string B (210b). For example, the conductive strip (230h) serves as or otherwise implements an inductor segment (218) to connect the combined capacitor (222) and the combined capacitor (223) in series. Thus, the combined capacitor (222) and the inductor segment (218) form one of the plurality of capacitor-conductor segments of the distributed capacitor string B (210b). Similarly, the combined capacitor (223) and the inductor segment (219) form another of the plurality of capacitor-conductor segments of the distributed capacitor string B (210b). In the distributed capacitor string B (210b), the inductor segments (215), (218), (219), etc., are attached to a single surface (i.e., surface C (220c)) of the dielectric material sheet. For example, one electrode of the combined capacitor (223) and the inductive segment (218) are integrated into a single conductive strip (230h) attached to surface C (210c), while the other electrode of the combined capacitor (223) and the inductive segment (219) are integrated into a single conductive strip (230j) attached to the same surface C (210c).In this context, each capacitor-wire segment shown in distributed capacitor string B (210B) is an integrated capacitor-wire segment of the second type.

[0165] As mentioned above, respectively in the above Figure 2D and 2E The wire loop (204) and rectangular loop (206) depicted in the figure can be based on distributed capacitor string A (210a), distributed capacitor string B (210b), or a combination thereof. In other words, the first type of integrated capacitor-wire segment in distributed capacitor string A (210a) and / or the second type of integrated capacitor-wire segment in distributed capacitor string B (210b) can be included in the above Figure 2D and 2E Although a specific number of integrated capacitor-wire segments is shown in the distributed capacitor string A (210a) and distributed capacitor string B (210b) above, the wire loop (204) and / or rectangular loop (206) may also include a greater number of either type of integrated capacitor-wire segments, or a lesser number of either type of integrated capacitor-wire segments than shown in the distributed capacitor string A (210a) and distributed capacitor string B (210b). In one or more embodiments, either or both types of integrated capacitor-wire segments may be combined with other types of capacitor-wire segments (e.g., based on discrete capacitors and inductors) to form the respective integrated capacitor-wire segments shown above. Figure 2D and 2E The wire loop (204) and / or rectangular loop (206) depicted in FIG.

[0166] Figure 2K An example configuration of a variable form factor transmitter (102) is shown based on the description of the legend (221) according to one or more embodiments. In one or more embodiments, the Figure 2K Therefore, the embodiments of the present invention should not be considered as limited to Figure 2K Specific arrangement of modules shown.

[0167] like Figure 2K As shown, the power transmitter (250) depicted based on the legend (221) shows the same as above Figure 2E The rectangular loop (206) of the power transmitter (250) is based on the above reference Figure 2J Specifically, a portion (224) of the rectangular loop (206) corresponds to Figure 2J3D view of the distributed capacitor string A (210a) depicted in FIG. In other words, Figure 2J The distributed capacitor string A (210a) described in FIG corresponds to a cross section of the portion (224) (indicated by the double-arrow dashed line). In order to clearly illustrate the above 2D form factor, the thickness of the conductive tape and dielectric material sheet in the distributed capacitor string A (210a) is omitted in the 3D view.

[0168] The RF characteristics of the rectangular loop (206) are described below, where the width, length, and number of overlapping regions of the rectangular loop (206) are represented by a, b, and n, respectively. The overlapping area A between two adjacent conductive strips can be calculated using equation (16), where the conductive strip width, conductive strip length, and overlapping region distance are represented by w, l, and x, respectively.

[0169] A=w×x Equation (16)

[0170] The capacitance of each overlapping region can be calculated using equation (17), where the dielectric constant and thickness of the dielectric material sheet are denoted as ε and d, respectively.

[0171]

[0172] The total capacitance of the rectangular loop (206) can be calculated using equation (18).

[0173]

[0174] The total inductance of the rectangular loop (206) can be calculated using equations (19) and (20).

[0175]

[0176]

[0177] The resonant frequency ω of the rectangular loop (206) can be calculated using equation (21) o .

[0178]

[0179] Other relationships between the resonant frequency and other parameters of the rectangular loop (206) include equation (22), equation (23), and equation (24).

[0180]

[0181]

[0182]

[0183] Table 2 lists four examples of RF characteristics of the rectangular loop (206) based on the above equations.

[0184] Table 2

[0185]

[0186] In one or more embodiments, the power transmitter (250) is configured based on a predetermined wireless power transmission area. For example, the predetermined wireless power transmission area can be a desktop surface where one or more mobile receiver devices (e.g., mobile phones) are placed to receive wireless power transmission. The rectangular loop (206) can be removably or permanently set along a path based on the desktop surface. For example, the path can be an edge of the desktop surface, above or below the desktop surface, on a fixture or ceiling above the desktop surface, on the floor below the desktop surface, or embedded in the floor below the desktop surface, etc. The power supply (108) is connected to the capacitor-wire segment via terminals A (202a) and B (202b) and can be plugged into a power outlet on the wall near the desktop surface. The dielectric material sheet (225) surrounds at least a portion of the path to implement the capacitor of the rectangular loop (206) and provide mechanical support for the rectangular loop (206).

[0187] In another example, the predetermined wireless power transmission area can be a space adjacent to a window, wherein one or more receiver devices (e.g., mobile phones) are positioned in or near the space to receive wireless power transmission. The rectangular loop (206) can be removably or permanently positioned along a path based on the window. For example, the path can be the edge of a window frame, in front of or behind a window glass surface, embedded in the window glass or window frame, etc. The power supply (108) can be plugged into a power outlet on the wall where the window is mounted, or connected to a power outlet behind the wall surface.

[0188] In one or more embodiments, one or more of the dielectric material sheet, conductive tape, and / or integrated capacitor-wire segments may be rigid or flexible, transparent, translucent, or opaque, depending on their respective thickness and / or composition. Figure 2K The 2D form factors of the dielectric material sheet, conductive ribbon, and / or integrated capacitor-conductor segment are shown as rectangular in FIG, but the dielectric material sheet, conductive ribbon, and / or integrated capacitor-conductor segment can also exhibit 2D form factors different from the shapes shown (e.g., polygonal, circular, oval, elliptical, spiral, or a combination thereof). Although the conductive ribbon in the rectangular loop (206) follows the Figure 2KThe conductive strip in the rectangular loop (206) may follow a different path outlining a different shape, which may change the rectangular loop (206) into a loop having a different shape, such as a polygonal, circular, oval, elliptical, spiral, or a combination thereof. Figure 2K A specific number of conductive strips and / or integrated capacitor-wire segments in the rectangular loop (206) is shown, but the power transmitter (250) may also include a greater number of integrated capacitor-wire segments or a lesser number of integrated capacitor-wire segments than shown.

[0189] Figure 2L An example configuration of a variable form factor transmitter (102) according to one or more embodiments is shown. In one or more embodiments, the Figure 2L Therefore, the embodiments of the present invention should not be considered as limited to Figure 2L The specific arrangement of modules is shown in .

[0190] like Figure 2L As shown, the power transmitter (260) depicted based on the legend (231) shows the same as above Figure 2K The top view of the power transmitter (250) depicted corresponds to an example configuration. In particular, the top view has a viewing direction along the third dimension, which is perpendicular to the surface of the power transmitter (250) (e.g., surface A (220a), surface B (220b)). The power transmitter (260) includes a rectangular loop (206a) that is implemented using a dielectric material sheet (251) and is connected to a power source (108). The rectangular loop (206a) and the dielectric material sheet (251) are the above Figure 2K Variations of the depicted rectangular loop (206) and dielectric material sheet (225). For example, rectangular loop (206a) and rectangular loop (206) have different numbers of capacitor-conductor segments. Additionally, dielectric material sheet 251 has openings (233) cut out of dielectric material sheet 251.

[0191] In one or more embodiments, the power source (108) is implemented using at least a flexible circuit having a thin insulating polymer film having a conductive circuit pattern and an electronic chip attached thereto. For example, the flexible circuit can be attached to and / or mechanically supported by a sheet of dielectric material (251). Figure 2M Example details of a portion of the power transmitter 260 including the power source 108 are shown in FIG.

[0192] like Figure 2MAs shown, the power supply (108) includes a flexible circuit (108a) connected to a plurality of conductive strips attached to the surface of a dielectric material sheet (251). The conductive strips include spiral A (209a), spiral B (209b), spiral C (209c), and spiral D (209d). One end of spiral A (209a) is represented as terminal A (204a), one end of spiral B (209b) is represented as terminal B (204b), one end of spiral C (209c) is represented as terminal C (204c), and one end of spiral D (209d) is represented as terminal D (204d). The other ends of spiral A (209a) and spiral B (209b) are connected together using a conductive bridge A (209d) to realize the secondary winding of the isolation transformer included in the power supply (108). The other ends of spiral C (209c) and spiral D (209d) are connected together using a conductive bridge B (209e) to realize the primary winding of the isolation transformer. Conductive bridge A (209d) and conductive bridge B (209e) can be realized using insulated wires or other electrical connection devices. The primary winding and the secondary winding are wound around each other to provide the inductive coupling effect of the isolation transformer. In addition, certain capacitors (represented as C1 and C2) included in the power supply (108) can be connected to terminals A (204a), terminal B (204b), terminal C (204c) and terminal D (204d). Capacitors C1 and C2 can be discrete capacitors soldered to the terminals, or can be capacitors realized using additional conductive tapes attached to two opposing surfaces of the dielectric material sheet (251). For example, the isolation transformer and capacitors C1 and C2 can be part of or associated with an impedance matching circuit to match a predetermined output impedance of the power supply (108) to a predetermined output impedance of the power supply (108). Figure 2L A string of distributed capacitors in the rectangular loop (206a) depicted in FIG.

[0193] Figure 2N The present invention shows a method based on the above embodiment according to one or more embodiments. Figure 2K An example of an application of the wireless power transmission area of ​​the power transmitter (250) depicted in FIG. In one or more embodiments, the wireless power transmission area may be omitted, repeated and / or replaced. Figure 2N Therefore, the embodiments of the present invention should not be considered as limited to Figure 2N Specific arrangement of modules shown.

[0194] like Figure 2NAs shown, the wireless power transmission area includes a tabletop (600) in which the rectangular loop (206) of the power transmitter (250) follows the edge of the tabletop (600). A sheet of dielectric material (225) is placed on top of the tabletop (600), wherein the thickness of the sheet of dielectric material (225) is omitted for clarity. The power cord and power plug of the power supply (108) are also omitted. Receiver device A (500a) and receiver device B (500b) receive wireless power transmission from the power transmitter (250) to illuminate a string of decorative light emitting diodes (LEDs) attached to the bottom of the glass. Reference is made below to Figure 5A 、 5B 5D and 5E describe examples of receiver device A (500a) and receiver device B (500b). In addition, receiver device C (500c) is a commercially available product that receives wireless power transmission from power transmitter (250) to charge the battery of a mobile device (500) such as a mobile phone, tablet computer, or notebook computer. Table 3 shows the input power and input current of four example load conditions of power transmitter (250).

[0195] Table 3

[0196]

[0197] With the above Figure 2J The distributed capacitor string A (210a) and distributed capacitor string B (210b) described in FIG. 1 are similar. Figure 2P 1 shows other configurations of variable form factor transmitters according to one or more embodiments. In particular, the overlapping portion of the two conductive films corresponds to a capacitor, while the non-overlapping portion of either conductive film corresponds to an inductor. In one or more embodiments, the following may be omitted, repeated, and / or replaced: Figure 2P Therefore, the embodiments of the present invention should not be considered as limited to Figure 2P Specific arrangement of modules shown.

[0198] like Figure 2PAs shown, distributed capacitor string C (210c), distributed capacitor string D (210d), and distributed capacitor string E (210e) are three additional example configurations of the variable form factor transmitter (102) depicted in Figures 1.1 and 1.2 above. According to the legend (300), the dielectric is a layer that separates the two layers of conductive film. Mechanical support is not provided by the dielectric, but by a separate and distinct insulating mechanical substrate, which is shown as being below both the conductive film layer and the dielectric layer. The dielectric can include an oxide layer grown on the surface of one of the conductive film layers, which can be a metal conductor. The dielectric layer can cover the entire upper surface of the lower conductive layer, as shown in distributed capacitor string C (210c), or the dielectric layer can cover only the overlapping area, as shown in distributed capacitor string D (210d).

[0199] Alternatively, as shown in distributed capacitor string E (210e), the dielectric can be composed of a thin film of insulating material to which both the upper and lower conductive films are adhered. However, the dielectric may be too thin to provide sufficient mechanical support, in which case all three layers can be stacked on top of an additional insulating layer that provides mechanical support for the dielectric and the upper / lower conductive films.

[0200] Figure 4A A schematic diagram of an example RF power supply according to one or more embodiments of the present invention is shown. In particular, Figure 4A The exemplary RF power supply (108) shown in FIG can be based on the ISM band as above Figure 1A 、 1C , 2B, 2C, 2D, 2K, 2L and 2M. Specifically, Figure 4A The example RF power supply (108) shown includes the same Figure 1A 、 1C , 2B, 2C, 2D, 2K, 2L and 2M correspond to the two terminals of the power supply (108) terminal A (204a) and terminal B (204b). The schematic includes commercial part numbers for capacitors, inductors and resistors of various RLC circuit components and various integrated circuit components. In particular, the inductors labeled L1 and L2 correspond to the above Figure 2M The capacitors marked C1 and C2 correspond to the primary conductive winding and the secondary conductive winding shown in FIG. Figure 2M In one or more embodiments, the capacitors of the same name may be omitted, repeated, and / or replaced. Figure 4A Therefore, the embodiments of the present invention should not be considered as limited to Figure 4A The specific arrangement of modules is shown in .

[0201] Figure 4B A schematic diagram of an example RF power supply connected to an equivalent circuit according to one or more embodiments of the present invention is shown. In particular, Figure 4B The example RF power supply (108) shown in FIG can be based on the ISM band as above Figure 1A 、 1C , 2B, 2C, 2D, 2K and 2L. Specifically, Figure 4B The example RF power supply (108) shown includes terminals A (204a) and B (204b), which correspond to the above Figure 1A 、 1C , 2B, 2C, 2D, 2K and 2L. The schematic diagram includes various RLC circuit components of capacitors, inductors and resistors, as well as commercial part numbers of various integrated circuit components. In particular, the equivalent circuit (206b) represents the above Figure 2K and 2L The rectangular loop (206) or rectangular loop (206a) shown in FIG. In one or more embodiments, the rectangular loop (206) may be omitted, repeated, and / or replaced. Figure 4B Therefore, the embodiments of the present invention should not be considered as limited to Figure 4B Specific arrangement of modules shown.

[0202] Figure 5A A schematic diagram of an exemplary receiver device A (500a) according to one or more embodiments of the present invention is shown. In one or more embodiments, the Figure 5A Therefore, the embodiments of the present invention should not be considered to be limited to Figure 5A Specific settings for the modules shown in .

[0203] like Figure 5A As shown, the receiver device A (500a) includes a plurality of light emitting diodes (LEDs) (e.g., LED (502)) connected in parallel to form an LED string. Both ends of the LED string are connected to a rectifier circuit A (501a) to form a loop. For example, the loop can be used as above Figure 1AA circular loop of a mobile LED lighting device used within a wireless power transmission area (101) depicted in FIG. In one or more embodiments of the present invention, a rectifier circuit A (501a) includes capacitors C1, C2, and C3 and rectifier diodes D1 and D2. When an oscillating magnetic field is present in the receiver device A (500a), a change in the magnetic flux through the loop of the LED string induces a voltage difference between the two ends of the LED string. The induced voltage difference oscillates over time. Capacitor C3 is adjusted to resonate the LED string with the oscillating magnetic field, thereby enhancing the induced oscillating voltage. Rectifier diodes D1 and D2 rectify the induced oscillating voltage to generate a DC voltage difference between the outer wire (503a) and the inner wire (503b) of the LED string, thereby powering the parallel-connected LEDs (e.g., LED (502)). Capacitors C1 and C2 serve as RF bypass capacitors to keep the outer wire (503a) and the inner wire (503b) of the LED string from appearing shorted to the RF current. The configuration of the receiver device A (500a) limits the loop voltage by the combined forward voltage drop across the LED in series with the rectifier diode D1 or D2, which improves safety for the user.

[0204] Similar to Figure 5A , Figure 5B An example receiver device B (500b) is shown, which is a larger version of receiver device A (500a) having multiple rectifier circuits (i.e., rectifier circuit B (501b), rectifier circuit C (501c), rectifier circuit D (501d), rectifier circuit E (501e)). Receiver device B (500b) operates substantially the same as receiver device A (500a). The number of segments in receiver device B (500b) can be selected to provide optimal impedance matching for the load (i.e., LEDs connected in parallel).

[0205] Apart from Figure 5A and 5B In addition, Figure 5C Schematic diagrams of other example receiver arrangements are shown.

[0206] Figure 5C A schematic diagram of an exemplary receiver device circuit (500c) according to one or more embodiments of the present invention is shown. In one or more embodiments, the receiver device circuit (500c) is used for various types of receiver devices having different shapes, sizes, form factors, etc., for use as described above. Figure 1A Various types of mobile or stationary applications within the wireless power transmission area (101) are shown. In one or more embodiments, at least the inductor L of the receiver device circuit (500c) is placed within the wireless power transmission area (101) for receiving wireless power transmission. Figure 5CThe remaining components shown in FIG are configured to convert the received wireless power into a power supply which is supplied to the load (received by the resistor R L Represents a suitable format for consumption.

[0207] like Figure 5C As shown, the inductor L is tuned together with the capacitors C1, C2 and C3 to be above the reference Figures 1A to 2G The variable form factor transmitter (102) and the RF power supply (108) described herein resonate at a characteristic frequency. The value of capacitor C1 is selected to provide impedance matching between the resonant receiver and the input of the DC-DC converter (504). The DC-DC converter (504) converts the rectified voltage to a constant voltage to drive the load R L Even in the case where the receiver device circuit (500c) moves through an area of ​​varying magnetic field strength within the wireless power transmission area (101), the DC-DC converter (504) allows the receiver device circuit (500c) to supply power to the load R L Provides a constant voltage. Note that the load R L It does not have to be a linear device (i.e. a device with a linear relationship between voltage and current). L Examples include, but are not limited to, LEDs, microcontrollers, motors, sensors, actuators, etc.

[0208] Figure 5D FIG. 5 is a schematic diagram of another exemplary receiver device circuit (500d) according to one or more embodiments of the present invention. The inductor L and capacitors C1 and C2 are tuned to the reference voltage. Figures 1A to 2G The variable form factor transmitter (102) and the RF power supply (108) described herein resonate at a characteristic frequency. The value of capacitor C1 is selected to provide impedance matching between the resonant receiver and the LED load. A bridge rectifier converts the RF voltage present on capacitor C1 into a DC voltage that drives the LED. For example, the LED may correspond to a string of decorative light emitting diodes (LEDs) attached to the bottom of the glass, with the LEDs on the top. Figure 2N Depicted in.

[0209] Figure 5E Shown above Figure 5D Layout diagram (500e) of an example receiver device circuit (500d) depicted in FIG. Inductor L is comprised of multiple turns of conductive traces in the form of a flat spiral on the surface of a printed circuit board (PCB). Capacitors C1 and C2 are placed in series with the spiral at location (501). A second layer of traces is used on the PCB to allow connections across the multiple turns of inductor L. Note also that C1 and C2 can be placed in series with the turns of inductor L at any point. For example, at Figure 5EIn FIG, capacitor C2 is placed across the discontinuity in the center of inductor L. This arrangement helps maintain symmetry in voltage distribution across the turns of inductor L.

[0210] In one or more embodiments of the present invention, receiver device A (500a), receiver device B (500b), receiver device circuit (500c), or receiver device circuit (500d) can wirelessly receive power from any electromagnetic transmitter (e.g., a dipole transmitter (e.g., a magnetic dipole transmitter), a loop antenna with distributed capacitance, a parallel line transmission line with distributed capacitance, a shielded transmission line with distributed capacitance, etc.). In one or more embodiments of the present invention, receiver device A (500a), receiver device B (500b), receiver device circuit (500c), and / or receiver device circuit (500d) are placed within a wireless power transmission area (101) as receiver device (A), receiver device (B), receiver device (C), receiver device (D), receiver device (E), or receiver device (F) to wirelessly receive power from a variable form factor transmitter (102).

[0211] Figures 6A-6F According to the legend (600) the above Figures 1A-1C Schematic diagram and layout diagram of a variation of the variable form factor transmitter (102) depicted in FIG. In one or more embodiments of the present invention, Figures 6A-6F The variable form factor transmitter (102) shown may include or otherwise be based on the above referenced Figures 2A-2P For clarity, the example configuration described is Figures 6A-6F The distributed capacitors may not be explicitly shown. In one or more embodiments, Figures 6A-6F The wireless power transmission area (101) shown may be a larger wireless power transmission area. A larger wireless power transmission area, or simply a larger area, has a dimension (e.g., length, width, diameter, etc.) that exceeds the wavelength corresponding to the aforementioned characteristic frequency of the variable form factor transmitter (102).

[0212] In one or more embodiments of the present invention, Figures 6A-6F The variable shape factor emitter (102) shown in can be arranged as a two-dimensional spatial periodic structure to suppress far-field radiation due to oscillating current density. In particular, the following reference Figures 7A-7F Description Figures 6A-6F Suppression of far-field radiation in a variable form factor transmitter (102) is shown.

[0213] In one or more embodiments, the Figures 6A-6FTherefore, the embodiments of the present invention should not be considered as limited to Figures 6A-6F The specific arrangement of modules is shown in .

[0214] like Figure 6A As shown, the variable form factor transmitter (102) includes a plurality of cross-coupled segments (e.g., segment A (601), segment B (601b), segment C (601c), etc.) that are arranged within or near the wireless power transmission area (101). As used herein, a segment is a continuous portion of the variable form factor transmitter (102). For example, the segment can be the segment shown above. Figure 2F . In one or more embodiments, the segments are arranged in a loop form factor that substantially encloses the loop area and have at least one pair of terminals for electrically connecting to adjacent segments (referred to as neighbors). Adjacent segments are two segments without any intervening segments therebetween. In one or more embodiments, the adjacent segments are electrically connected to each other to pass current from one segment to another. For example, segment A (601) has a pair of terminals (602a) for connecting to another pair of terminals (602b) of segment B (601b). In another example, segment B (601b) has two pairs of terminals for connecting to two adjacent segments (i.e., segment A (601a) and segment C (601c)). In one or more embodiments, the current flowing in each segment induces a magnetic field that is substantially orthogonal to the loop area of ​​the segment. The direction of the induced magnetic field depends on the direction of rotation of the current flowing through the segment. The direction of rotation is one of clockwise and counterclockwise. In one or more embodiments, the current is an alternating current in which the direction of all currents reverses during half of the cycle. According to the right-hand rule of electromagnetism, the direction of the induced magnetic field is related to the direction of rotation of the flowing current.

[0215] In one or more embodiments, the segments of the variable form factor transmitter (102) are configured to transmit RF power across the wireless power transmission region (101) via a near electromagnetic field of the variable form factor transmitter (102) from a radio frequency (RF) power source and based at least in part on the characteristic frequency.

[0216] In one or more embodiments, each segment includes one or more sides, wherein adjacent sides of adjacent segments are configured to conduct current in opposite rotational directions. For example, current flows in a counterclockwise direction in segment A (601a) and segment C (601c), such that the induced magnetic field is in a magnetic field direction A, which corresponds to the current flowing out of the loop area of ​​segment A (601a) and segment C (601c) toward Figure 6A In contrast, the current flows in the clockwise direction in segment B (601b), so that the induced magnetic field is in the magnetic field direction B, which corresponds to the loop region flowing into segment B (601b) away from Figure 6A Since the directions of the magnetic fields induced by adjacent segments are opposite, the radiation loss of wireless power transmission caused by the far electromagnetic field of the variable form factor transmitter (102) is reduced. The repeating pattern of opposite magnetic field directions (i.e., out-of-phase directions) in adjacent segments is called a checkerboard phase pattern. Figure 6A shows a one-dimensional checkerboard pattern. An example of a two-dimensional checkerboard pattern is shown in the following Figures 6E-6G Shown in.

[0217] In one or more embodiments, the RF power supply includes a plurality of lock-in amplifiers disposed in at least a portion of the segments of the variable form factor transmitter (102). For example, Figure 6A Each segment shown includes a phase-locked RF amplifier. In one or more embodiments, phase locking between segments is achieved using a phase-locked loop and a master-slave topology, where all phase-locked RF amplifiers share a master clock signal. Figure 6A Connected segments forming a single loop are depicted, but in an alternative configuration with disconnected but coupled loops, each loop can have a lock-in RF amplifier that measures the phase difference between it and its neighbors and adjusts its phase to be opposite to the average phase of its nearest neighbors. In this case, the multiple lock-in amplifiers of the variable form factor transmitter (102) automatically arrange themselves into an alternating phase checkerboard pattern without requiring any centralized control. As used herein, alternating phase means that the currents flowing in adjacent segments have opposite directions of rotation.

[0218] In one or more embodiments, the segments of the variable form factor transmitter (102) have the same shape and / or size. In one or more embodiments, one or more segments of the variable form factor transmitter (102) may have a different shape and / or size than the remaining segments in the variable form factor transmitter (102). In one or more embodiments, the segments of the variable form factor transmitter (102) are arranged in a one-dimensional or multi-dimensional repeating structure.

[0219] Figure 6B Shown above Figure 6A A schematic layout diagram of a variation of the example variable form factor transmitter (102) depicted in FIG, wherein the RF power supply comprises a single RF amplifier. Figure 6B As shown in , each segment is associated with multiple magnetic direction signs to illustrate a substantially uniform magnetic field across the entire loop area.

[0220] Figure 6C Shown above Figure 6ASchematic layout diagram of a variation of the example variable form factor transmitter (102) depicted in FIG, wherein the segments are divided into two separate parts, represented as variable form factor transmitter A (102a) and variable form factor transmitter B (102b), powered by separate RF amplifiers labeled "A" and "B," respectively. In one or more embodiments, variable form factor transmitter A (102a) and variable form factor transmitter B (102b) are physically offset by half the segment width and driven with a relative phase shift of 90 degrees. In particular, this arrangement eliminates the need for Figure 6B The arrangement shown has a zero point in the vertical component of the magnetic field. A phase shift of 90 degrees has no effect on radiation losses.

[0221] Figure 6D Shown above Figure 6C A schematic layout diagram of a variation of the example variable form factor transmitter (102) depicted in FIG, wherein variable form factor transmitter A (102a) is not explicitly driven by an RF amplifier. Instead, the magnetic field induced from variable form factor transmitter B (102b) induces currents flowing in the segments of variable form factor transmitter A (102a). Although variable form factor transmitters A (102a) and B (102b) are physically and electrically independent of each other, they become magnetically coupled resonators.

[0222] In the case of a variable form factor transmitter (102) composed of multiple magnetically coupled segments, the resonant properties of the combined structure can be used to ensure that the correct phase relationship exists between the magnetically coupled segments without the need for active phase control. The effect exploited in this case is the frequency division generated between any two or more coupled resonators. When the resonators are arranged in a periodic structure, the resonant eigenfrequencies approach the form of a continuous band as the size of the structure expands without limit. Bloch's theorem applies to such a structure, and the eigenexcited modes are described by Bloch wave functions. The eigenmode with the highest spatial frequency has the lowest temporal frequency. This highest spatial frequency eigenmode corresponds to the desired checkerboard phase pattern. Therefore, by driving the structure with the lowest temporal eigenfrequency within the Bloch band, the correct phase relationship between the individual variable form factor transmitters can be ensured.

[0223] In one or more embodiments, the wireless power transfer operates at a fixed predetermined frequency. Therefore, the system of magnetic coupling segments is designed so that the lowest time-frequency eigenmode in the Bloch band has a resonant frequency equal to the desired predetermined frequency for the wireless power transfer.

[0224] A system of magnetically coupled segments can be driven by an amplifier connected to a single segment. In this case, as long as the aforementioned resonant conditions are met, RF power will propagate through the structure to establish the aforementioned checkerboard phase pattern. However, if the magnetically coupled segments exhibit any radiation losses, the amplitude of the magnetic field will geometrically decay with each segment-to-segment transition. Therefore, depending on the size of the system, it may be necessary to drive the system from multiple points. If this is the case, each individual amplifier must be properly phase-locked to maintain the desired checkerboard phase pattern.

[0225] Note that when the total length of the wires in a single segment approaches half the free-space wavelength of the operating frequency, a significant amount of charge will accumulate on the wire structure due to self-capacitance. The solution is to add distributed capacitors in series with the segments at regular intervals. In other words, each segment is constructed as a distributed capacitor string as described above.

[0226] Figure 6E Shown above Figure 6A Schematic layout diagram of a variation of the example variable form factor transmitter (102) depicted in FIG, wherein the segments have a substantially rectangular shape arranged to cover a larger two-dimensional geographic area. Note that Figure 6E The transmitter depicted in consists of multiple disconnected inductively coupled wire loops. Figure 6D As with the transmitter shown in , this inductive coupling ensures that power is evenly distributed throughout the structure.

[0227] Figure 6F Shown above Figure 6E A schematic layout diagram of a variation of the example variable form factor transmitter (102) depicted in FIG. 1 , wherein the segments are connected according to an endless knot pattern.

[0228] Figure 6G Shown above Figure 6D A schematic layout diagram of a variation of the example variable form factor transmitter (102) depicted in FIG. Figure 6E and 6F Compared to the four-neighbor configuration depicted in , each segment has three neighbors (i.e., adjacent segments).

[0229] Figures 7A-7F The suppression of far-field radiation by an oscillating current density arranged in a two-dimensional spatial periodic structure is shown. Figure 7A A two-dimensional spatially periodic current distribution is shown that lies entirely in the xy plane. Assume that vectors a1 and a2 represent the two original translation vectors of the structure.

[0230] The position-space current density function J(x) has the following characteristics:

[0231] J(x+n1a1+n2a2)=J(x) (1)

[0232] Where n1 and n2 are arbitrary integers. Equation 1 expresses the discrete translational symmetry of a spatially periodic structure.

[0233] The reciprocal lattice vectors b1 and b2 can be written as functions of the original translation vector

[0234] b1≡2πa2·(a1∧a2) -1 (2)

[0235] b2≡-2πa1·(a1∧a2) -1 (3)

[0236] Where ^ represents the wedge product of two vectors. Reciprocal lattice vectors have the following properties:

[0237] b n ·a m =2πδ nm (4)

[0238] Among them, δ nm is the Kronecker delta function.

[0239] In addition, the current density is specified with an additional symmetry:

[0240]

[0241] The conditions specified in Equation 5 ensure that the current density exhibits a checkerboard pattern of translational symmetry in addition to the periodic translational symmetry described by Equation 1. Figure 7A An inspection of will show that the current distribution depicted therein obeys the translational symmetry of the checkerboard pattern described by Equation 5.

[0242] assumed represents the spatial Fourier transform of the current density, where k is the spatial wave vector.

[0243] Figure 7B shows the reciprocal lattice in Fourier space. Figure 7B As depicted, except for the infinite extension parallel to k z axis and k x -k y Except for the singular lines centered at each lattice point of the reciprocal lattice in the plane, the function It will be zero everywhere.

[0244] The condition specified in Equation 5 implies the following condition in Fourier space:

[0245]

[0246]

[0247] Equation 7 shows that The dot product k·(±a1 / 2±a2 / 2) must be zero at any point where it is an integer multiple of 2π. At a lattice point in the reciprocal lattice, the wave vector k can be expressed as:

[0248] k=n1b1+n2b2 (8)

[0249] Where n1 and n2 are integers. Therefore, at each lattice point of the reciprocal lattice, will be zero:

[0250]

[0251] Condition 9 will be satisfied at all lattice points where both integers n1 and n2 are odd or even. Lattice points that can take non-zero values ​​are those where one of the two integers is odd and the other is even.

[0252] Figure 7C Shows k x -k y In the plane A point that can take a non-zero value. Function It is composed of singular lines, which are k x -k y These points in the plane are centered and along k z The axis extends infinitely.

[0253] Assume that the current distribution J(x) oscillates sinusoidally in time with an angular frequency ω. Let c denote the speed of light in the surrounding medium, and let κ = ω / c denote the free-space wave number of the electromagnetic wave propagating at the angular frequency ω. The power radiated by the current density J(x) is given by the following integral performed in Fourier space:

[0254]

[0255] in, in, is the directional unit vector of the outgoing radiation, and ∫dΩ is angularly integrated over all directions of . Note that Equation 10 is valid only for divergence-free (i.e., ) current distribution is effective.

[0256] The integration in Equation 10 is performed over the surface of a sphere in Fourier space centered at the origin and of radius κ. Figure 7D and 7E The results of case (a) and case (b) are shown in k x -k yThe circular cross-section of the surface in the plane. In particular, Figure 7D An example case (a) is shown where far-field radiation is suppressed. In case (a), the magnitude of wave number κ is smaller than both |b1| and |b2|. In contrast, Figure 7E An example case (b) is shown in which far-field radiation is not suppressed. In case (b), the magnitude of κ is greater than one of |b1| and |b2|.

[0257] In case (a), the sphere of radius κ does not Any singular line on which it takes a nonzero value intersects. Therefore, the function The value of is zero everywhere on the surface of the sphere, and the integral of Equation 10 is exactly zero for case (a).

[0258] In case (b), Some of the singular lines that take non-zero values ​​intersect the surface of a sphere of radius κ. Therefore, for case (b), the integral of Equation 10 is non-zero.

[0259] Therefore, the radiated power will be suppressed as long as the following conditions are met:

[0260] κ<min(|b1|,|b2|) (11)

[0261] Note that the checkerboard pattern translational symmetry expressed by Equation 5 ensures the suppression of far-field radiation that occurs when Equation 11 is satisfied. This is because the checkerboard pattern translational symmetry forces The amplitude is zero at all lattice points (including the origin) defined by Equation 9. If The magnitude of is not zero at the origin of the reciprocal lattice, then will have along k z The singular line along the axis will intersect the sphere centered at the origin, regardless of the radius of the sphere. Therefore, the integral in Equation 10 is non-zero for all values ​​of κ.

[0262] Figure 7F An example of a rectangular checkerboard grid arranging the current density is shown. The two original translation vectors are:

[0263] a1=we1+he2 (12)

[0264] a2=-we1+he2 (13)

[0265] Where w and h are the width and height of the rectangular unit cell, and where e1 and e2 are unit vectors pointing in the x and y directions respectively. The reciprocal lattice vectors are:

[0266]

[0267]

[0268] The two reciprocal lattice vectors have the same magnitude, given by:

[0269]

[0270] The condition for suppressing far-field radiation can be expressed as:

[0271]

[0272] This condition can also be expressed in terms of the free-space wavelength λ = 2π / κ:

[0273]

[0274] In the case of h>>w, the rectangular grid approaches a zebra stripe pattern, and the condition for radiation suppression becomes:

[0275] λ>2w (19)

[0276] Figure 8 A flow chart of a method according to one or more embodiments of the present invention is shown. In one or more embodiments, the method can be based on the above Figures 6A-6G One or more variable form factor transmitters as depicted in FIG. In different embodiments of the present invention, the steps of FIG. 1 may be omitted, repeated, and / or performed in a different order. Figure 8 Therefore, the embodiments of the present invention should not be considered as limited to Figure 8 The specific number and arrangement of steps shown.

[0277] Initially, in step 801, a variable form factor transmitter is configured to include at least a plurality of cross-coupling segments positioned within or near a predetermined wireless power transmission region. The predetermined wireless power transmission region includes dimensions exceeding a wavelength corresponding to a characteristic frequency of the variable form factor transmitter. In one or more embodiments, one or more cross-coupling segments are constructed using a string of distributed capacitors.

[0278] In step 802, a plurality of lock-in amplifiers are disposed in at least a portion of a cross-coupling section as a radio frequency (RF) power source for wireless power transmission.

[0279] In step 803 , RF power is transmitted across a predetermined wireless power transmission region via a near electromagnetic field of a variable form factor transmitter from an RF power source and based at least in part on a characteristic frequency.

[0280] In step 804 , radiation loss of wireless power transmission due to a far electromagnetic field of the variable form factor transmitter is reduced based on the oppositely directed magnetic fields induced by adjacent cross-coupling segments.

[0281] In step 805, a receiver device is positioned within a predetermined wireless power transmission area to receive RF power transmission. Specifically, a portion of RF power transmitted from an RF power source via a variable form factor transmitter is received by the receiver device, wherein the characteristic frequency is substantially independent of the number or arrangement of the receiver devices.

[0282] While the present invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be designed without departing from the scope of the invention as disclosed herein. Accordingly, the scope of the present invention should be limited only by the claims appended hereto.

Claims

1. A method for wireless power transmission, comprising: adapting the variable form factor transmitter to at least a plurality of cross-coupling segments disposed within or near a predetermined wireless power transfer area; transmitting RF power across the predetermined wireless power transfer area via a near electromagnetic field of the variable form factor transmitter from a radio frequency (RF) power source and based at least in part on a characteristic frequency; as well as wherein, based on magnetic fields of opposite directions induced by adjacent cross-coupling segments among the plurality of cross-coupling segments, radiation loss of wireless power transmission caused by a far electromagnetic field of the variable form factor transmitter is reduced; The method further includes: providing a plurality of lock-in amplifiers as the RF power supply in at least a portion of the plurality of cross-coupling sections; Each of the plurality of cross-coupling segments includes a plurality of sides; and adjacent sides of adjacent cross-coupling segments are configured to conduct current in opposite rotational directions.

2. The method according to claim 1, in, The plurality of cross-coupling sections are arranged in or near the predetermined wireless power transmission area according to an endless knot pattern.

3. The method according to claim 1, in, A size of the predetermined wireless power transmission area exceeds a wavelength corresponding to a characteristic frequency of the variable form factor transmitter.

4. The method according to claim 1, further comprising: forming one or more of the plurality of cross-coupled sections using a string of distributed capacitors; connecting a plurality of capacitors in series via at least a plurality of conductor segments to form the string of distributed capacitors; wherein each of the plurality of capacitors comprises a predetermined capacitance; wherein each of the plurality of conductor segments comprises a predetermined segment length and a predetermined inductance per unit length; and The characteristic frequency depends at least on the predetermined capacitance and the predetermined inductance per unit length.

5. The method according to claim 1, further comprising: providing a plurality of receiver devices within the predetermined wireless power transmission area; wherein a portion of the RF power transmitted from the RF power source via the variable form factor transmitter is received by the plurality of receiver devices, and The characteristic frequency is independent of the number or arrangement of the plurality of receiver devices.

6. A transmitter for wireless power transmission, comprising: a plurality of cross-coupling segments disposed within or near a predetermined wireless power transmission area; The plurality of cross-coupling sections are configured as follows: transmitting RF power across the predetermined wireless power transfer region via a near electromagnetic field of the transmitter from a radio frequency (RF) power source and based at least in part on a characteristic frequency; and reducing radiation loss of wireless power transmission due to a far electromagnetic field of the transmitter based on magnetic fields of opposite directions induced by adjacent cross-coupling segments of the plurality of cross-coupling segments; The RF power supply includes: a plurality of lock-in amplifiers disposed in at least a portion of the plurality of cross-coupling sections; Each of the plurality of cross-coupling segments includes a plurality of sides; and adjacent sides of adjacent cross-coupling segments are configured to conduct current in opposite rotational directions.

7. The transmitter according to claim 6, in, The plurality of cross-coupling sections are arranged in or near the predetermined wireless power transmission area according to an endless knot pattern.

8. The transmitter according to claim 6, in, The transmitter is a variable form factor transmitter; and Wherein, a size of the predetermined wireless power transmission area exceeds a wavelength corresponding to a characteristic frequency of the variable form factor transmitter.

9. The transmitter of claim 6, one or more of the plurality of cross-coupling sections comprising: a plurality of capacitors, each capacitor having a predetermined capacitance; a plurality of conductor segments, each conductor segment having a predetermined segment length and a predetermined inductance per unit length, wherein the plurality of capacitors are connected in series at least via the plurality of conductor segments to form a string of distributed capacitors; and The characteristic frequency depends at least on the predetermined capacitance and the predetermined inductance per unit length.

10. A system for wireless power transmission, comprising: a plurality of cross-coupling segments disposed within or near a predetermined wireless power transmission area; as well as a radio frequency (RF) power source coupled to the plurality of cross-coupling sections, The plurality of cross-coupling sections are configured as follows: transferring RF power from the RF power source and based at least in part on a characteristic frequency, across the predetermined wireless power transfer region via the near electromagnetic field of the plurality of cross-coupling segments; and reducing radiation loss of wireless power transmission caused by far electromagnetic fields of the plurality of cross-coupling segments based on magnetic fields of opposite directions induced by adjacent cross-coupling segments of the plurality of cross-coupling segments; The RF power supply includes: a plurality of lock-in amplifiers disposed in at least a portion of the plurality of cross-coupling sections; Each of the plurality of cross-coupling segments includes a plurality of sides; and adjacent sides of adjacent cross-coupling segments are configured to conduct current in opposite rotational directions.

11. The system according to claim 10, in, The plurality of cross-coupling sections are arranged in or near the predetermined wireless power transmission area according to an endless knot pattern.

12. The system according to claim 10, in, A size of the predetermined wireless power transmission area exceeds a wavelength corresponding to characteristic frequencies of the plurality of cross-coupling sections.

13. The system of claim 10, wherein one or more of the plurality of cross-coupling sections comprises: a plurality of capacitors, each capacitor having a predetermined capacitance; a plurality of conductor segments, each conductor segment having a predetermined segment length and a predetermined inductance per unit length; wherein the plurality of capacitors are connected in series at least via the plurality of conductor segments to form a string of distributed capacitors; and The characteristic frequency depends at least on the predetermined capacitance and the predetermined inductance per unit length.

14. The system of claim 10, further comprising: a plurality of receiver devices disposed within the predetermined wireless power transmission area; wherein a portion of the RF power transmitted from the RF power source via the plurality of cross-coupling sections is received by the plurality of receiver devices; and The characteristic frequency is independent of the number or arrangement of the plurality of receiver devices.

15. A method for wireless power transmission, comprising: Adapting at least a first variable form factor transmitter and a second variable form factor transmitter to be respectively arranged in at least a first set of cross-coupling segments and a second set of cross-coupling segments within or near a predetermined wireless power transmission area, the first set of cross-coupling segments having at least a first terminal and a second terminal, and the second set of cross-coupling segments having at least a first terminal and a second terminal; as well as transmitting RF power across the predetermined wireless power transfer region via a near electromagnetic field of the first variable form factor transmitter and the second variable form factor transmitter from a first radio frequency (RF) power source electrically coupled to first and second terminals of the first set of cross-coupling segments and from a second RF power source electrically coupled to first and second terminals of the second set of cross-coupling segments, wherein the first RF power source and the second RF power source are driven by a first drive signal and a second drive signal, respectively; The method further includes: providing a plurality of first lock-in amplifiers as the first RF power supply in at least a portion of the first set of cross-coupling sections, and providing a plurality of second lock-in amplifiers as the second RF power supply in at least a portion of the second set of cross-coupling sections; Each cross-coupling segment in the first group of cross-coupling segments includes a plurality of sides; adjacent sides of adjacent cross-coupling segments in the first group of cross-coupling segments are configured to conduct current in opposite rotational directions; each cross-coupling segment in the second group of cross-coupling segments includes a plurality of sides; adjacent sides of adjacent cross-coupling segments in the second group of cross-coupling segments are configured to conduct current in opposite rotational directions.

16. The method according to claim 15, in, the first set of cross-coupling segments and the second set of cross-coupling segments being spatially offset relative to each other by a preselected spatial offset to minimize inductive coupling between the first set of cross-coupling segments and the second set of cross-coupling segments; as well as The first drive signal and the second drive signal are out of phase with each other by a preselected phase shift amount, and the preselected phase shift amount ensures that at least a predetermined minimum level of wireless power can be obtained at any location within the predetermined wireless power transmission area.

17. The method according to claim 16, in, The preselected spatial offset is approximately equal to half the width of a segment in the first set of cross-coupling segments.

18. The method according to claim 16, wherein The preselected phase shift amount is approximately 90 degrees.

19. The method according to claim 15, further comprising: providing a plurality of receiver devices within the predetermined wireless power transmission area; wherein a portion of the RF power transmitted from the first RF power source and the second RF power source via the first variable form factor transmitter and the second variable form factor transmitter, respectively, is received by the plurality of receiver devices, and The characteristic frequencies of the first variable form factor transmitter and the second variable form factor transmitter are independent of the number or arrangement of the plurality of receiver devices within the predetermined wireless power transmission area.

20. A system for wireless power transmission, comprising: a first set of cross-coupling segments disposed within or near a predetermined wireless power transfer area, the first set of cross-coupling segments having at least a first terminal and a second terminal; a second set of cross-coupling segments disposed within or near the predetermined wireless power transmission area, the second set of cross-coupling segments having at least a first terminal and a second terminal; as well as a first radio frequency (RF) power source electrically coupled to the first terminal and the second terminal of the first set of cross-coupling segments, the first RF power source electrically coupled to the first set of cross-coupling segments, the first set of cross-coupling segments comprising a first variable form factor transmitter operating at a characteristic frequency; as well as a second RF power source electrically coupled to the first and second terminals of the second set of cross-coupling segments, the second RF power source electrically coupled to the second set of cross-coupling segments, the second set of cross-coupling segments comprising a second variable form factor transmitter operating at the characteristic frequency; The first set of cross-coupling sections is configured as follows: transferring RF power from the first RF power source across the predetermined wireless power transfer region via the near electromagnetic field of the first set of cross-coupling segments; The second set of cross-coupling sections is configured as follows: transferring RF power from the second RF power source across the predetermined wireless power transfer region via the near electromagnetic field of the second set of cross-coupling segments; and Wherein, the first RF power supply and the second RF power supply are driven by a first driving signal and a second driving signal respectively; The first RF power supply includes: a plurality of first lock-in amplifiers disposed in at least a portion of the first set of cross-coupling sections; the second RF power supply includes: a plurality of second lock-in amplifiers disposed in at least a portion of the second set of cross-coupling sections; wherein each of the plurality of cross-coupling segments in the first group includes a plurality of sides; adjacent sides of adjacent cross-coupling segments in the first group are configured to conduct current in opposite rotational directions; and each of the plurality of cross-coupling segments in the second group includes a plurality of sides; adjacent sides of adjacent cross-coupling segments in the second group are configured to conduct current in opposite rotational directions.

21. The system according to claim 20, in, the first set of cross-coupling segments and the second set of cross-coupling segments being spatially offset relative to each other by a preselected spatial offset to minimize inductive coupling between the first set of cross-coupling segments and the second set of cross-coupling segments; as well as The first drive signal and the second drive signal are out of phase with each other by a preselected phase shift amount, and the preselected phase shift amount ensures that at least a predetermined minimum level of wireless power can be obtained at any location within the predetermined wireless power transmission area.

22. The system of claim 20, wherein one or more of the cross-coupling segments in the first group comprises: a plurality of capacitors, each capacitor having a predetermined capacitance; a plurality of conductor segments, each conductor segment having a predetermined segment length and a predetermined inductance per unit length; wherein the plurality of capacitors are connected in series at least via the plurality of conductor segments to form a string of distributed capacitors; and The characteristic frequency depends at least on the predetermined capacitance and the predetermined inductance per unit length.

23. The system of claim 22, further comprising: a plurality of receiver devices disposed within the predetermined wireless power transmission area; wherein a portion of the RF power transmitted from the first RF power source and the second RF power source via the first set of cross-coupling sections and the second set of cross-coupling sections, respectively, is received by the plurality of receiver devices; and The characteristic frequency is independent of the number or arrangement of the plurality of receiver devices.

24. The system of claim 21, wherein: The preselected spatial offset is equal to half the width of a segment in the first set of cross-coupling segments.

25. The system of claim 24, wherein: The preselected phase shift amount is 90 degrees.

Images