Microstrip antennas for wireless power transmitters

A microstrip antenna for use in a wireless power transmission system and a method for forming the microstrip antenna are described. The antenna includes a first multi-layer printed circuit board (PCB) that includes a top surface and a bottom surface. The top and bottom surfaces of the first multi-layer PCB include a first electrically conductive material. The antenna includes a second multi-layer PCB that includes a top surface and a bottom surface. The top and bottom surfaces of the second multi-layer PCT include a second electrically conductive material. A first plurality of vias each substantially pass through the top and bottom surfaces of the first multi-layer PCB. A second plurality of vias each substantially pass through the top and bottom surfaces of the second multi-layer PCB. The antenna further comprises a dielectric slab that is configured to receive the first multi-layer PCB and the second multi-layer PCB.

TECHNICAL FIELD

The disclosed embodiments relate generally to wireless power transmission systems, and in particular, to microstrip antennas for wirelessly transmitting and/or receiving power.

BACKGROUND

Portable electronic devices, such as laptop computers, mobile phones, tablets, and other electronic devices, require frequent charging of a power-storing component (e.g., a battery) to operate. Many electronic devices require charging one or more times per day. Often, charging an electronic device requires manually connecting an electronic device to an outlet or other power source using a wired charging cable. In some cases, the power-storing component is removed from an electronic device and inserted into charging equipment. Accordingly, charging is time consuming, burdensome, and inefficient because users must carry around multiple charging cables and/or other charging devices, and frequently must locate appropriate power sources to charge their electronic devices. Additionally, conventional charging techniques potentially deprive a user of the ability to use the device while it is charging, and/or require the user to remain next to a wall outlet or other power source to which their electronic device or other charging equipment is connected.

Additionally, existing patch antennas used for transmission of power waves have large cross-sectional areas, such as 6″ by 6″ for transmission of power waves at a frequency of 900 MHz. Due to these large cross-sectional areas, integrating these existing patch antennas with consumer electronic devices results in noticeable and undesired changes to an aesthetic appearance of the consumer electronic devices, thereby reducing the likelihood that consumers will be willing to install such devices in their homes, office spaces, and other areas.

SUMMARY

There is a need for improved antenna designs that help to address the shortcomings of conventional charging systems described above. In particular, there is a need for antennas (e.g., microstrip antennas) that have a form factor that is suitable for integration with consumer devices. The antennas described herein address these shortcomings and have a form factor that is suitable for integration with consumer devices. For example, in some embodiments the antennas discussed herein have a largest cross-sectional dimension of approximately two inches, making integration with consumer devices such as sound bars, televisions, media entertainment systems, light fixtures, portable air conditioning/heater systems, dashboard and glove compartments in automobiles, devices embedded in seat-backs (e.g., in trains, busses and airplanes), advertisement panels, and other consumer devices appropriate without impacting aesthetic appeal of these consumer devices, thereby ensuring that consumers will be more receptive to installing such transmitter devices (e.g., a sound bar with the novel microstrip antenna integrated therein) in their homes, offices, and other spaces.

In some embodiments, an antenna for use in a wireless power transmission system includes a first multi-layer printed circuit board (PCB) that includes a top surface and a bottom surface that is opposite the top surface, and the top and bottom surfaces of the first multi-layer PCB include a first electrically conductive material. The antenna additionally comprises a second multi-layer PCB that includes a top surface and a bottom surface that is opposite the top surface, and the top and bottom surfaces of the second multi-layer PCT include a second electrically conductive material. A first plurality of vias each substantially pass through the top and bottom surfaces of the first multi-layer PCB. A second plurality of vias each substantially pass through the top and bottom surfaces of the second multi-layer PCB. The antenna further includes a dielectric slab that is configured to receive the first multi-layer PCB and the second multi-layer PCB.

In some embodiments, a method for forming an antenna includes forming a dielectric assembly by coupling a dielectric slab to a first multi-layer PCB and a second multi-layer PCB. The first multi-layer PCB includes a top surface and a bottom surface that is opposite the top surface. The top and bottom surfaces of the first multi-layer PCB include a first electrically conductive material. A first plurality of vias each substantially pass through the top and bottom surfaces of the first multi-layer PCB. The second multi-layer PCB includes a top surface and a bottom surface that is opposite the top surface. The top and bottom surfaces of the second multi-layer PCT include a second electrically conductive material. A second plurality of vias each substantially pass through the top and bottom surfaces of the second multi-layer PCB. The method also includes coupling at least one feed to the dielectric assembly.

DETAILED DESCRIPTION

Numerous details are described herein in order to provide a thorough understanding of the example embodiments illustrated in the accompanying drawings. However, some embodiments may be practiced without many of the specific details, and the scope of the claims is only limited by those features and aspects specifically recited in the claims. Furthermore, well-known processes, components, and materials have not been described in exhaustive detail so as not to unnecessarily obscure pertinent aspects of the embodiments described herein.

A microstrip antenna is described herein, which address the shortcomings described above in conventional charging systems and with existing antenna designs. In some embodiments, the microstrip antenna described herein is a component of a transmitter and/or a receiver of a wireless power transmission environment100(e.g., as described with regard toFIG. 1). For example, a microstrip antenna transmits power waves and/or receives transmitted power waves.

In some embodiments, one or more transmitters of a wireless power transmission environment generate power waves to form pockets of energy at target locations and adjust power wave generation based on sensed data to provide safe, reliable, and efficient wirelessly-delivered power to receivers (and devices associated therewith). In some embodiments, a controlled “pocket of energy” (e.g., a region in which available power is high due to constructive interference of power waves) and/or null spaces (e.g., a region in which available power is low or nonexistent due to destructive interference of power waves) may be formed by convergence of the power waves transmitted into a transmission field of the one or more transmitters. In some embodiments, the one or more transmitters include an array of the microstrip antennas described herein (e.g., in reference toFIGS. 2-7C), and the array of the microstrip antennas is used to transmit the power waves. For example, the antennas discussed herein may be integrated with consumer devices such as sound bars, televisions, media entertainment systems, light fixtures, and other consumer devices, to produce a respective transmitter that remains aesthetically appealing, yet still capable of transmitting power waves sufficient to charge other electronic devices (e.g., cell phones, smart watches, etc).

In some embodiments, pockets of energy form at one or more locations in a two- or three-dimensional field due to patterns of constructive interference caused by convergences of transmitted power waves. Energy from the transmitted power waves may be harvested by receivers (i.e., received and converted into usable power) at the one or more locations.

In some embodiments, adaptive pocket-forming is performed, e.g., by adjusting power wave transmission to achieve a target power level for at least some of the power waves transmitted by the one or more transmitters. For example, a system for adaptive pocket-forming includes a sensor. In some embodiments, when the sensor detects an object, such as a sensitive object (e.g., a person, an animal, equipment sensitive to the power waves, and the like) within a predetermined distance (e.g., a distance within a range of 1-5 feet) of a pocket of energy, of one or more of the power waves, or of a transmitter, then a respective transmitter of the one or more transmitters adjusts one or more characteristics of transmitted power waves. Non-limiting examples of the one or more characteristics include: frequency, amplitude, trajectory, phase, and other characteristics used by one or more antennas of the one or more transmitters to transmit the power waves. As one example, in response to receiving information indicating that transmission of power waves by a respective transmitter of the one or more transmitters should be adjusted (e.g., a sensor senses a sensitive object within a predetermined distance of a respective target location), the adaptive pocket-forming process adjusts the one or more characteristics accordingly.

In some embodiments, adjusting the one or more characteristics includes reducing a currently generated power level at a location by adjusting one or more transmitted power waves that converge at the target location. In some embodiments, reducing a currently generated power level includes transmitting a power wave that causes destructive interference with at least one other transmitted power wave. For example, a power wave is transmitted with a first phase that is shifted relative to a second phase of at least one other power wave to destructively interfere with the at least one other power wave in order to diminish or eliminate the currently generated power level at the target location.

In some embodiments, adjusting the one or more characteristics includes increasing a power level for some of the transmitted power waves to ensure that the receiver receives adequate energy sufficient to quickly charge a power-storing component of an electronic device that is associated with the receiver.

In some embodiments, an object is “tagged” (e.g., an identifier of the object is stored in memory in association with a flag) to indicate that the detected object is a sensitive object. In response to detection of a particular object within a predetermined distance of a target location, a determination is made as to whether the particular object is a sensitive object. In some embodiments, this determination includes performing a lookup in the memory to check whether the particular object has been previously tagged and is therefore known as a sensitive object. In response to determining that the particular object is a sensitive object, the one or more characteristics used to transmit the power waves are adjusted accordingly.

In some embodiments, sensing a sensitive object includes using a series of sensor readings from one or more sensors to determine motion of an object within a transmission field of the one or more transmitters. In some embodiments, sensor output from one or more sensors is used to detect motion of the object approaching within a predetermined distance of a pocket of energy or of power waves used to form the pocket of energy. In response to a determination that a sensitive object is approaching (e.g., moving toward and/or within a predefined distance of a pocket of energy), the currently generated power level at the location of the pocket of energy is reduced. In some embodiments, the one or more sensors include sensors that are internal to the one or more transmitters and/or the receiver. In some embodiments, the one or more sensors include sensors that are external to the one or more transmitters and the receiver. In some embodiments, the one or more sensors include thermal imaging, optical, radar, and other types of sensors capable of detecting objects within a transmission field.

Although some embodiments herein include the use of RF-based wave transmission technologies as a primary example, it should be appreciated that the wireless charging techniques that might be employed are not be limited to RF-based technologies and transmission techniques. Rather, it should be appreciated that additional or alternative wireless charging techniques may be utilized, including any suitable technology and technique for wirelessly transmitting energy so that a receiver is capable of converting the transmitted energy to electrical power. Such technologies or techniques may transmit various forms of wirelessly transmitted energy including the following non-limiting examples: ultrasound, microwave, laser light, infrared, or other forms of electromagnetic energy.

FIG. 1is a block diagram of components of wireless power transmission environment100, in accordance with some embodiments. Wireless power transmission environment100includes, for example, transmitters102(e.g., transmitters102a,102b. . .102n) and one or more receivers120(e.g., receivers120a,120b. . .120n). In some embodiments, each respective wireless power transmission environment100includes a number of receivers120, each of which is associated with a respective electronic device122.

An example transmitter102(e.g., transmitter102a) includes, for example, one or more processor(s)104, a memory106, one or more antenna arrays110(e.g., including antenna elements structured as described below in reference toFIGS. 2-7C), and one or more communications components112, and/or one or more transmitter sensors114. In some embodiments, these components are interconnected by way of a communications bus108. References to these components of transmitters102cover embodiments in which one or more than one of each of these components (and combinations thereof) are included.

In some embodiments, memory106stores one or more programs (e.g., sets of instructions) and/or data structures, collectively referred to as “modules” herein. In some embodiments, memory106, or the non-transitory computer readable storage medium of memory106stores the following modules107(e.g., programs and/or data structures), or a subset or superset thereof:information received from receiver120(e.g., generated by receiver sensor128and then transmitted to the transmitter102a);information received from transmitter sensor114;an adaptive pocket-forming module that adjusts one or more power waves transmitted by one or more transmitters102; and/ora beacon transmitting module that transmits a communication signal118for detecting a receiver120(e.g., within a transmission field of the one or more transmitters102).

The above-identified modules (e.g., data structures and/or programs including sets of instructions) need not be implemented as separate software programs, procedures, or modules, and thus various subsets of these modules may be combined or otherwise re-arranged in various embodiments. In some embodiments, memory106stores a subset of the modules identified above. In some embodiments, an external mapping memory131that is communicatively connected to communications component112stores one or more modules identified above. Furthermore, the memory106and/or external mapping memory131may store additional modules not described above. In some embodiments, the modules stored in memory106, or a non-transitory computer readable storage medium of memory106, provide instructions for implementing respective operations in the methods described below. In some embodiments, some or all of these modules may be implemented with specialized hardware circuits that subsume part or all of the module functionality. One or more of the above-identified elements may be executed by one or more of processor(s)104. In some embodiments, one or more of the modules described with regard to memory106is implemented on memory104of a server (not shown) that is communicatively coupled to one or more transmitters102and/or by a memory of electronic device122and/or receiver120.

In some embodiments, a single processor104(e.g., processor104of transmitter102a) executes software modules for controlling multiple transmitters102(e.g., transmitters102b. . .102n). In some embodiments, a single transmitter102(e.g., transmitter102a) includes multiple processors104, such as one or more transmitter processors (configured to, e.g., control transmission of signals116by antenna array110), one or more communications component processors (configured to, e.g., control communications transmitted by communications component112and/or receive communications by way of communications component112) and/or one or more sensor processors (configured to, e.g., control operation of transmitter sensor114and/or receive output from transmitter sensor114).

Receiver120(e.g., a receiver of electronic device122) receives power signals116and/or communications118transmitted by transmitters102. In some embodiments, receiver120includes one or more antennas124(e.g., antenna array including multiple antenna elements), power converter126, receiver sensor128and/or other components or circuitry (e.g., processor(s)140, memory142, and/or communication component(s)144). In some embodiments, these components are interconnected by way of a communications bus143. References to these components of receiver120cover embodiments in which one or more than one of each of these components (and combinations thereof) are included. Receiver120converts energy from received signals116(e.g., power waves) into electrical energy to power and/or charge electronic device122. For example, receiver120uses power converter126to convert captured energy from power waves116to alternating current (AC) electricity or direct current (DC) electricity usable to power and/or charge electronic device122. Non-limiting examples of power converter126include rectifiers, rectifying circuits, voltage conditioners, among suitable circuitry and devices.

In some embodiments, receiver120is a standalone device that is detachably coupled to one or more electronic devices122. For example, electronic device122has processor(s)132for controlling one or more functions of electronic device122and receiver120has processor(s)140for controlling one or more functions of receiver120.

In some embodiments, receiver is a component of electronic device122. For example, processor(s)132controls functions of electronic device122and receiver120.

In some embodiments, electronic device122includes processor(s)132, memory134, communication component(s)136, and/or battery/batteries130. In some embodiments, these components are interconnected by way of a communications bus138. In some embodiments, communications between electronic device122and receiver120occur via communications component(s)136and/or144. In some embodiments, communications between electronic device122and receiver120occur via a wired connection between communications bus138and communications bus146. In some embodiments, electronic device122and receiver120share a single communications bus.

In some embodiments, receiver120receives one or more power waves116directly from transmitter102. In some embodiments, receiver120harvests power waves from one or more pockets of energy created by one or more power waves116transmitted by transmitter102.

In some embodiments, after the power waves116are received and/or energy is harvested from a pocket of energy, circuitry (e.g., integrated circuits, amplifiers, rectifiers, and/or voltage conditioner) of the receiver120converts the energy of the power waves (e.g., radio frequency electromagnetic radiation) to usable power (i.e., electricity), which powers electronic device122and/or is stored to battery130of electronic device122. In some embodiments, a rectifying circuit of the receiver120translates the electrical energy from AC to DC for use by electronic device122. In some embodiments, a voltage conditioning circuit increases or decreases the voltage of the electrical energy as required by the electronic device122. In some embodiments, an electrical relay conveys electrical energy from the receiver120to the electronic device122.

In some embodiments, receiver120is a component of an electronic device122. In some embodiments, a receiver120is coupled (e.g., detachably coupled) to an electronic device122. In some embodiments, electronic device122is a peripheral device of receiver120. In some embodiments, electronic device122obtains power from multiple transmitters102and/or using multiple receivers120. In some embodiments, the wireless power transmission environment100includes a plurality of electronic devices122, each having at least one respective receiver120that is used to harvest power waves from the transmitters102into usable power for charging the electronic devices122.

In some embodiments, the one or more transmitters102adjust one or more characteristics (e.g., phase, gain, direction, and/or frequency) of power waves116. For example, a transmitter102(e.g., transmitter102a) selects a subset of one or more antenna elements of antenna array110to initiate transmission of power waves116, cease transmission of power waves116, and/or adjust one or more characteristics used to transmit power waves116. In some implementations, the one or more transmitters102adjust power waves116such that trajectories of power waves116converge at a predetermined location within a transmission field (e.g., a location or region in space), resulting in controlled constructive or destructive interference patterns.

In some embodiments, respective antenna arrays110of the one or more transmitters102may include a set of one or more antennas configured to transmit the power waves116into respective transmission fields of the one or more transmitters102. Integrated circuits (not shown) of the respective transmitter102, such as a controller circuit and/or waveform generator, may control the behavior of the antennas. For example, based on the information received from the receiver by way of the communications signal118, a controller circuit may determine a set of one or more characteristics or waveform characteristics (e.g., amplitude, frequency, trajectory, phase, among other characteristics) used for transmitting the power waves116that would effectively provide power to the receiver102and electronic device122. The controller circuit may also identify a subset of antennas from the antenna arrays110that would be effective in transmitting the power waves116. As another example, a waveform generator circuit of the respective transmitter102coupled to the processor104may convert energy and generate the power waves116having the waveform characteristics identified by the controller, and then provide the power waves to the antenna arrays110for transmission.

In some embodiments, constructive interference of power waves occurs when two or more power waves116are in phase with each other and converge into a combined wave such that an amplitude of the combined wave is greater than amplitude of a single one of the power waves. For example, the positive and negative peaks of sinusoidal waveforms arriving at a location from multiple antennas “add together” to create larger positive and negative peaks. In some embodiments, a pocket of energy is formed at a location in a transmission field where constructive interference of power waves occurs.

In some embodiments, destructive interference of power waves occurs when two or more power waves are out of phase and converge into a combined wave such that the amplitude of the combined wave is less than the amplitude of a single one of the power waves. For example, the power waves “cancel each other out,” thereby diminishing the amount of energy concentrated at a location in the transmission field. In some embodiments, destructive interference is used to generate a negligible amount of energy or “null” at a location within the transmission field where the power waves converge.

In some embodiments, the one or more transmitters102transmit power waves116that create two or more discrete transmission fields (e.g., overlapping and/or non-overlapping discrete transmission fields). In some embodiments, a first transmission field is managed by a first processor104of a first transmitter (e.g. transmitter102a) and a second transmission field is managed by a second processor104of a second transmitter (e.g., transmitter102b). In some embodiments, the two or more discrete transmission fields (e.g., overlapping and/or non-overlapping) are managed by the transmitter processors104as a single transmission field.

In some embodiments, communications component112transmits communication signals118by way of a wired and/or wireless communication connection to receiver120. In some embodiments, communications component112generates communications signals118used for triangulation of receiver120. In some embodiments, communication signals118are used to convey information between transmitter102and receiver120for adjusting one or more characteristics used to transmit the power waves116. In some embodiments, communications signals118include information related to status, efficiency, user data, power consumption, billing, geo-location, and other types of information.

In some embodiments, receiver120includes a transmitter (not shown), or is a part of a transceiver, that transmits communications signals118to communications component112of transmitter102.

In some embodiments, communications component112(e.g., communications component112of transmitter102a) includes a communications component antenna for communicating with receiver120and/or other transmitters102(e.g., transmitters102bthrough102n). In some embodiments, these communications signals118represent a distinct channel of signals transmitted by transmitter102, independent from a channel of signals used for transmission of the power waves116.

In some embodiments, the receiver120includes a receiver-side communications component (not shown) configured to communicate various types of data with one or more of the transmitters102, through a respective communications signal118generated by the receiver-side communications component. The data may include location indicators for the receiver102and/or electronic device122, a power status of the device122, status information for the receiver102, status information for the electronic device122, status information about the power waves116, and/or status information for pockets of energy. In other words, the receiver102may provide data to the transmitter102, by way of the communications signal118, regarding the current operation of the system100, including: information identifying a present location of the receiver102or the device122, an amount of energy received by the receiver120, and an amount of power received and/or used by the electronic device122, among other possible data points containing other types of information.

In some embodiments, the data contained within communications signals118is used by electronic device122, receiver120, and/or transmitters102for determining adjustments of the one or more characteristics used by the antenna array110to transmit the power waves106. Using a communications signal118, the transmitter102communicates data that is used, e.g., to identify receivers120within a transmission field, identify electronic devices122, determine safe and effective waveform characteristics for power waves, and/or hone the placement of pockets of energy. In some embodiments, receiver120uses a communications signal118to communicate data for, e.g., alerting transmitters102that the receiver120has entered or is about to enter a transmission field, provide information about electronic device122, provide user information that corresponds to electronic device122, indicate the effectiveness of received power waves116, and/or provide updated characteristics or transmission parameters that the one or more transmitters102use to adjust transmission of the power waves116.

As an example, the communications component112of the transmitter102communicates (e.g., transmits and/or receives) one or more types of data (including, e.g., authentication data and/or transmission parameters) including various information such as a beacon message, a transmitter identifier, a device identifier for an electronic device122, a user identifier, a charge level for electronic device122, a location of receiver120in a transmission field, and/or a location of electronic device122in a transmission field.

In some embodiments, transmitter sensor114and/or receiver sensor128detect and/or identify conditions of electronic device122, receiver120, transmitter102, and/or a transmission field. In some embodiments, data generated by transmitter sensor114and/or receiver sensor128is used by transmitter102to determine appropriate adjustments to the one or more characteristics used to transmit the power waves106. Data from transmitter sensor114and/or receiver sensor128received by transmitter102includes, e.g., raw sensor data and/or sensor data processed by a processor104, such as a sensor processor. Processed sensor data includes, e.g., determinations based upon sensor data output. In some embodiments, sensor data received from sensors that are external to the receiver120and the transmitters102is also used (such as thermal imaging data, information from optical sensors, and others).

In some embodiments, receiver sensor128is a gyroscope that provides raw data such as orientation data (e.g., tri-axial orientation data), and processing this raw data may include determining a location of receiver120and/or or a location of receiver antenna124using the orientation data.

In some embodiments, receiver sensor128includes one or more infrared sensors (e.g., that output thermal imaging information), and processing this infrared sensor data includes identifying a person (e.g., indicating presence of the person and/or indicating an identification of the person) or other sensitive object based upon the thermal imaging information.

In some embodiments, receiver sensor128includes a gyroscope and/or an accelerometer that indicates an orientation of receiver120and/or electronic device122. As one example, transmitters102receive orientation information from receiver sensor128and the transmitters102(or a component thereof, such as the processor104) use the received orientation information to determine whether electronic device122is flat on a table, in motion, and/or in use (e.g., next to a user's head).

In some embodiments, receiver sensor128is a sensor of electronic device122(e.g., an electronic device122that is remote from receiver102). In some embodiments, receiver120and/or electronic device122includes a communication system for transmitting signals (e.g., sensor signals output by receiver sensor128) to transmitter102.

In some embodiments, transmitter sensor114and/or receiver sensor128is configured for human recognition (e.g., capable of distinguishing between a person and other objects, such as furniture). Examples of sensor data output by human recognition-enabled sensors include: body temperature data, infrared range-finder data, motion data, activity recognition data, silhouette detection and recognition data, gesture data, heart rate data, portable devices data, and wearable device data (e.g., biometric readings and output, accelerometer data).

In some embodiments, transmitters102adjust one or more characteristics used to transmit the power waves116to ensure compliance with electromagnetic field (EMF) exposure protection standards for human subjects. Maximum exposure limits are defined by US and European standards in terms of power density limits and electric field limits (as well as magnetic field limits). These include, for example, limits established by the Federal Communications Commission (FCC) for maximum permissible exposure (MPE), and limits established by European regulators for radiation exposure. Limits established by the FCC for MPE are codified at 47 CFR § 1.1310. For electromagnetic field (EMF) frequencies in the microwave range, power density can be used to express an intensity of exposure. Power density is defined as power per unit area. For example, power density can be commonly expressed in terms of watts per square meter (W/m2), milliwatts per square centimeter (mW/cm2), or microwatts per square centimeter (μW/cm2). In some embodiments, output from transmitter sensor114and/or receiver sensor128is used by transmitter102to detect whether a person or other sensitive object enters a power transmission region (e.g., a location within a predetermined distance of a transmitter102, power waves generated by transmitter102, and/or a pocket of energy). In some embodiments, in response to detecting that a person or other sensitive object has entered the power transmission region, the transmitter102adjusts one or more power waves116(e.g., by ceasing power wave transmission, reducing power wave transmission, and/or adjusting the one or more characteristics of the power waves). In some embodiments, in response to detecting that a person or other sensitive object has entered the power transmission region, the transmitter102activates an alarm (e.g., by transmitting a signal to a loudspeaker that is a component of transmitter102or to an alarm device that is remote from transmitter102). In some embodiments, in response to detecting that a person or other sensitive object has entered a power transmission region, the transmitter102transmits a digital message to a system log or administrative computing device.

In some embodiments, antenna array110includes multiple antenna elements (e.g., configurable “tiles”) collectively forming an antenna array. Antenna array110generates power transmission signals, e.g., RF power waves, ultrasonic power waves, infrared power waves, and/or magnetic resonance power waves. In some embodiments, the antennas of an antenna array110(e.g., of a single transmitter, such as transmitter102a, and/or of multiple transmitters, such as transmitters102a,102b, . . . ,102n) transmit two or more power waves that intersect at a defined location (e.g., a location corresponding to a detected location of a receiver120), thereby forming a pocket of energy (e.g., a concentration of energy) at the defined location.

In some embodiments, transmitter102assigns a first task to a first subset of antenna elements of antenna array110, a second task to a second subset of antenna elements of antenna array110, and so on, such that the constituent antennas of antenna array110perform different tasks (e.g., determining locations of previously undetected receivers120and/or transmitting power waves116to one or more receivers120). As one example, in an antenna array110with ten antennas, nine antennas transmit power waves116that form a pocket of energy and the tenth antenna operates in conjunction with communications component112to identify new receivers in the transmission field. In another example, an antenna array110having ten antenna elements is split into two groups of five antenna elements, each of which transmits power waves116to two different receivers120in the transmission field.

In some embodiments, a microstrip antenna200(ofFIG. 2) is an antenna element of antenna array110of transmitter102. In some embodiments, a microstrip antenna200is an antenna element of antenna124of receiver120. Microstrip antenna200transmits and/or receives electromagnetic waves.

FIG. 2illustrates a cross-sectional view of a microstrip antenna200, in accordance with some embodiments. In some embodiments, the microstrip antenna200includes a first multi-layer printed circuit board (PCB)202, a second multi-layer PCB204, and a dielectric slab206. In some embodiments, the first multi-layer PCB202includes first PCB208. In some embodiments, the first PCB208includes electrically conductive material at the top side of first PCB208(e.g., a first layer210of the electrically conductive material) and at the bottom side of first PCB208(e.g., a second layer212of the electrically conductive material). In some embodiments, the second multi-layer PCB204includes second PCB214. In some embodiments, the second PCB214includes electrically conductive material at the top side of second PCB214(e.g., a first layer216of the electrically conductive material) and at the bottom side of second PCB214(e.g., a second layer218of the electrically conductive material). In some embodiments, the electrically conductive material is a metal, for example, copper, silver, gold, aluminum, and/or brass. In some embodiments, the electrically conductive material is laminated on tops and/or bottoms of the PCBs208and214during manufacture of the first multi-layer PCB202and the second multi-layer PCB204.

In some embodiments, a first set of vias220each pass through the first multi-layer PCB202. In some embodiments, a second set of vias222each pass through the second multi-layer PCB204.

In some embodiments, a first feed224passes at least partially through second multi-layer PCB204, dielectric slab206, and first multi-layer PCB202. In some embodiments, a second feed226passes at least partially through second multi-layer PCB204, dielectric slab206, and first multi-layer PCB202. For example, a microstrip antenna200that is a dual-polarized antenna includes two feeds (e.g., first feed224to transmit and/or receive horizontally polarized waves and second feed226to transmit and/or receive vertically polarized waves). In some embodiments, a microstrip antenna200that is a single-polarized antenna includes only a single feed (e.g., first feed224). First feed224and second feed226are, for example, metallic pins.

In some embodiments, a first signal (e.g., a first RF power wave) is provided to first feed224via a first cable228. In some embodiments, first feed224excites the microstrip antenna200using the first signal for transmission of RF power waves by the microstrip antenna200. In some embodiments, a second signal (e.g., a second RF power wave) is provided to second feed226via a second cable230. In some embodiments, second feed226excites the microstrip antenna200using the second signal for transmission of RF power waves by the microstrip antenna200. In some embodiments, first cable228and/or second cable230are coupled to an output of processor(s)104of transmitter102a(processor(s)102and transmitter102aare discussed in detail above in reference toFIG. 1).

Having a single microstrip antenna with two multi-layer PCBs at opposite ends of a dielectric slab helps to improve manufacturability of antennas. For example, in some embodiments, electrically conductive material is printed on PCBs208and214using established PCB printing techniques. In some embodiments, any desired slab of material is usable as a substrate (e.g., dielectric substrate206) to which multi-layer PCBs are attached.

FIG. 3illustrates a top view of a first multi-layer PCB202, in accordance with some embodiments. An electrically conductive material (e.g., layer210) is shown at the top of first PCB208.FIG. 3illustrates an embodiment in which first feed224and second feed226partially puncture first PCB208, causing distortion of the top surface of first PCB208. Distortion regions302and304show locations of first feed224and second feed226, respectively, within the first multi-layer PCB202.

A first set of vias220pass through the first multi-layer PCB202. In some embodiments, a y-axis distance306between vias of the plurality of vias220and/or an x-axis distance308between vias of the plurality of vias220is much smaller than a wavelength λ that corresponds to a target frequency (e.g., 900 MHz) for transmission and/or reception by microstrip antenna200. Additionally, the microstrip antenna200(of which PCB202is a component) also has a maximum cross-sectional dimension which is much smaller than this wavelength (as discussed below in reference toFIG. 4). For example, in some embodiments, y-axis distance306and/or x-axis distance308(or the maximum cross-sectional dimension of the microstrip antenna200) is equal to or less than λ/10 (e.g., λ/20). In some embodiments, y-axis distance306and/or x-axis distance308is 2.0 mm. In some embodiments, a diameter of a respective via of the plurality of vias220is less than or equal to 2.0 mm (e.g., 1.0 mm).

FIG. 4illustrates an x-axis dimension402and a y-axis dimension404of microstrip antenna200, in accordance with some embodiments. In some embodiments, one or more dimensions of microstrip antenna200are determined based on a target bandwidth. For example, in some embodiments, x-axis dimension402and/or y-axis dimension404is/are much smaller than a wavelength λ that corresponds to a target frequency (e.g., 900 MHz) of power waves transmitted by the microstrip antenna200. In some embodiments, the microstrip antenna200has an x-axis dimension402of less than or equal to 50.8 mm (e.g., 40 mm). In some embodiments, the microstrip antenna200has a y-axis dimension404of less than or equal to 50.8 mm (e.g., 30 mm). For example, in some embodiments, the microstrip antenna200has an x-axis dimension402of 25.4 mm and a y-axis dimension404of 25.4 mm.

FIG. 5is an expanded cross-sectional view of first multi-layer PCB202that illustrates a material formed on an interior surface of at least a subset of vias of the plurality of vias220, in accordance with some embodiments. In some embodiments, a via-coating material (e.g., via-coating material502and504) is formed on an interior surface of one or more vias (e.g., an interior surface of each via) of the plurality of vias220. For example, the interior surface of one or more vias is plated with the via-coating material. In some embodiments, the via-coating material is a heat-conducting material and/or an electrically-conductive material. In some embodiments, the via-coating material is conductively coupled to a first electrically conductive material (e.g., electrically conductive material210as shown at the top of first PCB208and/or electrically conductive material212as shown at the bottom of first PCB208). For example, the via-coating material is conductively coupled to a first electrically conductive material such that heat and/or electrons are conducted between electrically conductive layer210, the via-coating material, and electrically conductive layer212. In some embodiments, via-coating material is conductively coupled to a second electrically conductive material (e.g., electrically conductive material216as shown at the top of second PCB214and/or electrically conductive material218as shown at the bottom of second PCB214). In some embodiments, the via-coating material and the electrically conductive material (e.g., first electrically conductive material and/or second electrically conductive material) are the same material.

FIG. 6illustrates an array600of microstrip antennas, in accordance with some embodiments. In some embodiments, array600is used as an antenna array110of a transmitter102within a wireless power transmission environment100as illustrated inFIG. 1and described above. Array600includes a plurality of component antennas, such as multiple microstrip antennas200(e.g., first microstrip antenna200a, second microstrip antenna200b, and third microstrip antenna200c). Although three microstrip antennas are shown inFIG. 6, it will be recognized that other numbers of antennas may be included in array600, e.g., 2-10 antennas.

In some embodiments, formation of array600includes arranging the respective multi-layer PCBs of microstrip antennas200a,200b, and200c, and forming a single dielectric slab206relative to the respective multi-layer PCBs. For example, the respective multi-layer PCBs are exposed to a liquid state of the dielectric material and a dielectric slab is formed when the dielectric material transitions from a liquid state to a solid state. In other words, the dielectric slab206is formed around the respective multi-layer PCBs.

In some embodiments, formation of array600includes attaching respective multi-layer PCBs of microstrip antennas200a,200b, and200cto a dielectric slab206using an adhesive or other mechanical restraint.

In some embodiments, transmission of RF waves by array600is controlled by a plurality of control elements (not shown). In some embodiments, a respective control element of the plurality of control elements includes one or more feeds. For example, a first control element controls first feed224and/or second feed226. In some embodiments, a first control element causes microstrip antenna200ato transmit a first RF signal, a second control element causes microstrip antenna200bto transmit a second RF signal, and a third control element causes microstrip antenna200cto transmit a third RF signal. In some embodiments, the first RF signal is transmitted with at least one characteristic that is distinct from a corresponding characteristic associated with the second RF signal and/or the third RF signal. In some embodiments, the control elements receive signals from processor(s)104of transmitter102. For example, a control element includes an output terminal of processor(s)104and/or a communication channel from processor(s)104to a microstrip antenna200.

Although a horizontal arrangement of microstrip antennas200a,200b, and200cis shown inFIG. 6, it will be recognized that alternative arrangements may be used, such as a vertical arrangement of microstrip antennas200and/or a grid arrangement of microstrip antennas200.

In some embodiments, multiple antenna arrays600may be included in a respective transmitter102and each of the multiple antenna arrays may be configured to transmit power waves at different frequencies (e.g., a first antenna array maybe configured to transmit at 900 MHz and a second antenna array may be configured to transmit at 2.4 GHz). To allow for transmission at the different frequencies, each of the multiple antenna arrays may have antennas that are of different dimensions or shapes (e.g., the first antenna array may include larger antennas than the second antenna array).

FIGS. 7A-7Care a flowchart representation of a method700for forming an antenna, in accordance with some embodiments.

In some embodiments, forming an antenna optionally includes forming (702-a) a first multi-layer PCB202and forming (702-b) a second multi-layer PCB204. In some embodiments, forming the first multi-layer PCB202includes printing a first electrically conductive layer on the top and bottom surfaces of the first multi-layer PCB (e.g., printing the electrically conductive layer as shown at top surface210and bottom surface212of first PCB208,FIG. 2). In some embodiments, forming the second multi-layer PCB204includes printing the second electrically conductive layer on the top and bottom surfaces of the second multi-layer PCB (e.g., printing the electrically conductive layer as shown at top surface216and bottom surface218of second PCB214,FIG. 2).

In some embodiments, forming a multi-layer PCB includes coupling an electrically conductive material (e.g., copper tape or other conductive material) to a substrate (e.g., PCB) by lamination (e.g., using an adhesive such as glue). In some embodiments, a multi-layer PCB is formed using a holding structure such as one or more notches and/or tabs such that an electrically conductive material is physically held in place relative to a substrate by the holding structure.

In some embodiments, forming the first multi-layer PCB202optionally includes depositing (704-a) a first heat-conductive material on an interior surface of at least a subset of the first plurality of vias220. In some embodiments, forming the second multi-layer PCB204optionally includes depositing (704-b) a second heat-conductive material on an interior surface of at least a subset of the second plurality of vias222. For example, a first heat-conductive material is deposited on an interior surface of one or more vias as shown at502and504ofFIG. 5.

In some embodiments, depositing a first heat-conductive material on an interior surface of at least a subset of the first plurality of vias220includes depositing (706-a) the first heat-conductive material such that the first heat-conductive material (e.g., as shown at502and504ofFIG. 5) is thermally coupled to the first electrically conductive material (e.g., as shown at210and212ofFIG. 2) of the first multi-layer PCB202. In some embodiments, depositing a second heat-conductive material on an interior surface of at least a subset of the second plurality of vias includes depositing (706-b) the second heat-conductive material such that the second heat-conductive material is thermally coupled to the second electrically conductive material (e.g., as shown at216and218ofFIG. 2) of the second multi-layer PCB204. In some embodiments, the heat-conducting material is a metal such as copper, aluminum, brass, steel, and/or bronze.

Turning now toFIG. 7B, in some embodiments, forming an antenna includes forming (708) a dielectric assembly by coupling a dielectric slab206to a first multi-layer PCB202and a second multi-layer PCB204. The first multi-layer PCB202includes (708-a) a top surface and a bottom surface that is opposite the top surface. The top and bottom surfaces of the first multi-layer PCB202include a first electrically conductive material (e.g., as shown at210and212ofFIG. 2). A first plurality of vias220each substantially pass through the top and bottom surfaces of the first multi-layer PCB202. The second multi-layer PCB204includes (708-b) a top surface and a bottom surface that is opposite the top surface. The top and bottom surfaces of the second multi-layer PCT204include a second electrically conductive material (e.g., as shown at216and218ofFIG. 2). A second plurality of vias222each substantially pass through the top and bottom surfaces of the second multi-layer PCB204.

In some embodiments, dielectric slab206includes a dielectric material fabricated from an exotic and/or synthetic material, such as a material that has a high dielectric constant (e.g., a moldable ceramic). For example, in some embodiments, dielectric slab206has a dielectric constant between 1.0 and 40 (e.g., a dielectric constant of 30). In some embodiments, the dielectric slab206is formed from stone, ceramic, plastic, and/or glass, or gas (e.g., in a container). In some embodiments, dielectric slab206is fabricated from a material that is capable of insulating, reflecting, and/or absorbing electric current. In some embodiments, dielectric slab206is fabricated from one or more materials that are engineered to yield predetermined magnetic permeability and/or electrical permittivity values. In some embodiments, at least one of a magnetic permeability value or an electrical permittivity value of dielectric slab206is based upon at least one predetermined power-transfer requirement and/or compliance constraint (e.g., in compliance with one or more government regulations).

In some embodiments, coupling the dielectric slab206to the first multi-layer PCB202and the second multi-layer PCB204optionally includes (710) coupling the first multi-layer PCB202to the dielectric slab206using an adhesive (e.g., glue, epoxy, potting compound, or other suitable adhesive) and coupling the second multi-layer PCB204to the dielectric slab206using the adhesive.

In some embodiments, coupling the dielectric slab206to the first multi-layer PCB202and the second multi-layer PCB204optionally includes (712) arranging the first multi-layer PCB202and the second multi-layer PCB204relative to dielectric material while it is in a liquid state, wherein the first multi-layer PCB202and the second multi-layer PCB204have fixed positions within the dielectric slab206after the dielectric material of the dielectric slab206transitions from the liquid state to a solid state. For example, the dielectric material of dielectric slab206is a ceramic, plastic, or other state-changing material that is capable of transitioning from a liquid state to a set solid state. In some embodiments, the first multi-layer PCB202and the second multi-layer PCB204are coupled to the dielectric slab206by molding the dielectric material around the first multi-layer PCB202and the second multi-layer PCB204. For example, the dielectric slab206is shaped to include two reservoirs that are configured to receive the first and second multi-layer PCBs and the dielectric slab206is then baked so that the first and second multi-layer PCBs are then securely attached within the respective reservoirs of the dielectric slab206.

In some embodiments, forming an antenna includes coupling (714) at least one feed (e.g., first feed224and/or second feed226) to the dielectric assembly (e.g., dielectric slab206, first multi-layer PCB202, and second multi-layer PCB204). For example, the at least one feed is coupled to the dielectric assembly by inserting the at least one feed into the dielectric assembly (e.g., by drilling one or more holes at least partially through the dielectric slab206, first multi-layer PCB202, and second multi-layer PCB204and inserting the at least one feed into the one or more holes). In some embodiments, the at least one feed is coupled to the dielectric assembly by attaching the at least one feed to a surface of dielectric slab206, first multi-layer PCB202, and/or second multi-layer PCB204with adhesive or other coupling means.

In some embodiments, coupling the at least one feed to the dielectric assembly optionally includes inserting (716) the at least one feed into the dielectric assembly such that the at least one feed (e.g., first feed224and/or second feed226) at least partially passes through at least one of: the first multi-layer PCB202, the dielectric slab206, or the second multi-layer PCB204. For example, inFIG. 2, first feed224and second feed226are shown passing fully through second multi-layer PCB204, passing fully through the dielectric slab206, and passing partially through first multi-layer PCB202.

In some embodiments, the at least one feed substantially (e.g., at least halfway) passes through (718) the first multi-layer PCB202, the second multi-layer PCB204, and the dielectric slab206. For example, a feed substantially passes through a multi-layer PCB when the feed passes at least halfway from the bottom of the multi-layer PCB to the top of the multi-layer PCB.

In some embodiments, the first and second feeds are coupled to a power source and/or waveform generator (e.g., the power source and waveform generator described above in reference toFIG. 1) that provides a signal for transmission by an assembled antenna (e.g., microstrip antenna200,FIG. 2).

Features of the present invention can be implemented in, using, or with the assistance of a computer program product, such as a storage medium (media) or computer readable storage medium (media) having instructions stored thereon/in which can be used to program a processing system to perform any of the features presented herein. The storage medium (e.g., memory106) can include, but is not limited to, high-speed random access memory, such as DRAM, SRAM, DDR RAM or other random access solid state memory devices, and may include non-volatile memory, such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid state storage devices. Memory (e.g.,106,134, and/or142) optionally includes one or more storage devices remotely located from the CPU(s) (e.g., processor(s)104,132, and/or140). Memory (e.g.,106,134, and/or142), or alternatively the non-volatile memory device(s) within the memory, comprises a non-transitory computer readable storage medium.

Stored on any one of the machine readable medium (media), features of the present invention can be incorporated in software and/or firmware for controlling the hardware of a processing system (such as the components associated with the transmitters102and/or receivers120), and for enabling a processing system to interact with other mechanisms utilizing the results of the present invention. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments/containers.

Communication systems as referred to herein (e.g., communications components112,136, and/or144) optionally communicate via wired and/or wireless communication connections. Communication systems optionally communicate with networks, such as the Internet, also referred to as the World Wide Web (WWW), an intranet and/or a wireless network, such as a cellular telephone network, a wireless local area network (LAN) and/or a metropolitan area network (MAN), and other devices by wireless communication. Wireless communication connections optionally use any of a plurality of communications standards, protocols and technologies, including but not limited to radio-frequency (RF), radio-frequency identification (RFID), infrared, radar, sound, Global System for Mobile Communications (GSM), Enhanced Data GSM Environment (EDGE), high-speed downlink packet access (HSDPA), high-speed uplink packet access (HSUPA), Evolution, Data-Only (EV-DO), HSPA, HSPA+, Dual-Cell HSPA (DC-HSPDA), long term evolution (LTE), near field communication (NFC), ZigBee, wideband code division multiple access (W-CDMA), code division multiple access (CDMA), time division multiple access (TDMA), Bluetooth, Wireless Fidelity (Wi-Fi) (e.g., IEEE 102.11a, IEEE 102.11ac, IEEE 102.11ax, IEEE 102.11b, IEEE 102.11g and/or IEEE 102.11n), voice over Internet Protocol (VoIP), Wi-MAX, a protocol for e-mail (e.g., Internet message access protocol (IMAP) and/or post office protocol (POP)), instant messaging (e.g., extensible messaging and presence protocol (XMPP), Session Initiation Protocol for Instant Messaging and Presence Leveraging Extensions (SIMPLE), Instant Messaging and Presence Service (IMPS)), and/or Short Message Service (SMS), or any other suitable communication protocol, including communication protocols not yet developed as of the filing date of this document.