Patent Description:
Retail environments often experience moderate to high levels of ambient radio-frequency energy from various sources. For example, consumers and workers may carry smartphones into a store that operate using one or more frequency bands, such as the <NUM> LTE band. Stores may also have a WiFi network or be in proximity to a nearby WiFi network operating on the <NUM> or <NUM> frequencies. Retail environments may also have Bluetooth beacons, or Bluetooth low energy (LE) systems, to inform consumers through mobile marketing about available items of commerce available for purchase, or use Electronic Article Surveillance ("EAS") systems operating at <NUM> for loss prevention. Inventory control in retail environments can also use radio frequencies through the use of Radio Frequency Identification ("RFID") reader systems and RFID tags that are attached to items for sale. RFID systems can operate at ultra-high frequencies, for example between <NUM> to <NUM>. <CIT> discloses a system configured to self-harvest radio frequency signals transmitted by an associated wireless device wherein the system converts the collected radio frequency signals to a direct current signal compatible with charging requirements of the wireless device in order to supplement an electrical charge of a battery electrically connected to the wireless device. <CIT> discloses a system and device for harvesting various frequencies and polarizations of ambient radio frequency electromagnetic energy for making a passive sensor into an autonomous passive sensor adapted to collect and store data with time-stamping and computation when necessary even when an interrogating radio frequency identification (RFID) reader is not present. The source of ambient RF EM energy may include WiFi and/or cellular telephone base stations and the system and device disclosed allows for the recharging of energy storage units in active and battery assisted passive devices. <CIT> discloses methods, apparatuses, and systems for converting energy from electro-magnetic radiation into electric power using a simultaneous collector of ambient radio frequencies circuit. This is achieved by capturing EM radiation from a plurality of ambient signals using an array of antennas where each signal has a resonant frequency and aggregating the ambient signals to generate an aggregated signal having a single frequency with greater AC power than the AC power of each of the plurality of ambient signals individually. The aggregated signal is then converted into useable electric power using a rectifying circuit.

Aspects of the invention are disclosed in independent claim <NUM> and <NUM>.

According to certain embodiments, an energy harvesting system includes one or more antennas configured to receive one or more radio frequency signals from a source and an energy harvester configured to derive energy from the one or more radio frequency signals to power a power consuming device. The energy harvesting system can include a power integrator that stores the energy until needed by the power consuming device. The energy harvester can also be configured to extract data encoded in the radio frequency signals and transmit the data to the power consuming device, which can change its operation mode based on the received power or data. The energy harvesting system uses data communications to control power delivery from the source of the radio frequency signal based on the needs of the power consuming device.

In certain embodiments, an energy harvester includes a plurality of antennas and an energy harvester. The antennas are each tuned to distinct frequencies associated with different types of sources and configured to receive radio frequency signals from one or more sources substantially around the tuned frequencies. The energy harvester is configured to receive the radio frequency signals from the antennas, extract energy from the received signals, and provide power from the extracted energy to a power consuming device. The power consuming device is configured to perform one or more operations. Example sources can include radio frequency identification systems, electronic article surveillance systems, Bluetooth systems, WiFi networks, cellular networks, and continuous wave signal generators. For instance, the energy harvester, in one embodiment, could accumulate power from one or more local sources and re-transmit a signal on the same radio frequency. For instance, the extracted energy, such as from WiFi or Bluetooth sources, may transmit a Bluetooth beacon signal associated with the same radio signal.

According to some embodiments, a method includes receiving one or more radio frequency signals from one or more antennas, where each antenna may be tuned to a distinct frequency, extracting energy from the signals by an energy harvester, and providing power to a power consuming device from power derived from the extracted energy. The power consuming device is configured to perform one or more operations unassociated with the radio frequency signal. The method can include changing operation modes on the power consuming device based on the power received from the energy harvester. The energy harvester uses data communications to control power delivery from the source of the radio frequency signal based on the needs of the power consuming device.

Various embodiments will become better understood with regard to the following description, appended claims, and accompanying drawings.

The systems and methods disclosed herein are described in detail by way of examples and with reference to <FIG>. It will be appreciated that modifications to disclosed and described examples, arrangements, configurations, components, elements, apparatuses, devices methods, systems, etc. can suitably be made and may be desired for a specific application. In this disclosure, any identification of specific techniques, arrangements, etc. are either related to a specific example presented or are merely a general description of such a technique, arrangement, etc. Identifications of specific details or examples are not intended to be, and should not be, construed as mandatory or limiting unless specifically designated as such.

The systems and methods disclosed herein describe different modalities for capturing energy from nearby radio frequency emitting sources and the present invention is not limited to any one particular modality. Although the systems and methods described herein are particularly applicable to radio frequency emitted by RFID, EAS, WiFi, Bluetooth, and cellular devices, the system and methods can be adapted for use with other types of radiant energy. For example, any suitable source of radio frequency transmissions can be used.

Referring to <FIG>, an illustration of an energy harvesting system <NUM> is presented. The energy harvesting system <NUM> includes an energy harvester <NUM>, also referred to as an energy harvester host, that receives a radio frequency signal through at least one antenna <NUM>. The energy harvester <NUM> can receive radio frequency signals from mobile sources, such as a smartphone <NUM>, carried by a consumer or by staff. The radio frequency signal harvested by the energy harvester <NUM> can include data that is embedded, or encoded, in a carrier signal from the mobile device, or any radio transmission that can be considered as a carrier, such as a signal at a specific frequency- <NUM>- and a data modulation. All transmissions contain a carrier of some sort so that the total transmission is a carrier and some form of data modulation. All of the radio signal captured by the energy harvester <NUM> will be a modulated carrier. For example, a nearby smartphone <NUM> may communicate with infrastructure <NUM>, such as a WiFi network or a cellular network, or a nearby Bluetooth LE beacon. If power drops off by approximately a square law with distance from the emitter for far field coupling and the cube of the distance from the emitter for near field coupling, the nearby smartphone <NUM> is often a stronger source of radio frequency signals for the energy harvester <NUM> than the infrastructure <NUM> itself. For example, if the smartphone <NUM> is at <NUM> and the infrastructure <NUM> is <NUM> from the energy harvester <NUM>, and the smartphone <NUM> and infrastructure <NUM> are transmitting the same power and frequency, the power arriving at the energy harvester <NUM> from the infrastructure <NUM> will be approximately 18dB less than that from the smartphone <NUM>. The energy harvester <NUM> can also harvest energy from alternative sources <NUM>, which can include the infrastructure <NUM> or other sources such as RFID reader systems or other devices as described in greater detail below.

An example energy harvester <NUM> can comprise suitable circuits and electronics for deriving energy from radio frequency signals as would be understood in the art and providing power to a power consuming device <NUM>. In this example, the energy harvester <NUM> is converting an AC signal (the RF energy received) to a DC signal to power the consuming device- a rectifier. Rectification is achieved using a device that has a different forward and reverse path conduction for a voltage that is applied to it depending on which connection has a higher voltage than the other. A well-known example of this is a diode, which is a single diode and a capacitor that provides a smooth DC supply in order to take an RF AC signal and create a DC supply. The use of multiple diodes can improve the efficiency of the rectifier. For example, a structure with multiple diodes and capacitors, called a Cockroft Waltom multiplier, will produce a DC supply greater than the peak voltage of the RF AC signal. Other structures can act as rectifiers. For example, field effect transistors with the gate connected to the source or drain (depending on the type of FET) act as switches to pass or block the path through depending on whether the differential voltage is positive between source and drain or negative.

By way of analogy, an RFID transponder includes an antenna and/or tuning loop that is coupled to an RFID chip. The RFID chip includes electronics that accumulate energy from RF signals received through the antenna. The RFID chip turns on and transmits back a response code once the RFID chip receives sufficient power (e.g., in one embodiment, approximately 10µW depending on the chip type) from an RFID reader. The power received at the RFID from a reader depends on the emitted power and distance between tag and readers. Similarly, the energy harvester <NUM> can derive energy from RF signals emitted by RFID reader systems using similar antenna structures and electronics, but instead of using the power to allow an RFID chip to respond with a code, the energy harvester <NUM> can deliver power, or power and data, to a power consuming device <NUM>.

Similar structures and electronics can be used to derive energy from radio frequency signals from WiFi networks, Bluetooth systems, EAS systems, cellular networks, smart devices using radio frequencies such as Zigbee devices, and other sources of radio frequency energy. Advantageously, the energy harvester <NUM> can harvest RF signals from one kind of system and use captured energy for powering a power consuming device <NUM> that performs operations unassociated with the RF signals.

Example power consuming devices <NUM>, or power utilizing devices, can include, but are not limited to, Bluetooth LE beacons, WiFi transceivers, WiGig and chipe transceivers, active transmitters, RFID transponders, lighting modules, optical indicators, for example to alert consumers to the presence of consumable items available for purchase, wireless point of sale terminals, sensors such as environmental sensors, speakers or other sound generating elements, touch interfaces for consumers to interact with systems such as the energy harvesting system <NUM>, or a display. For example, the display can be a power consuming device <NUM> that, in one embodiment, is powered by an energy harvester <NUM>. In certain embodiments, the display can change modalities based on the power received from the energy harvester <NUM>, as described below in greater detail for <FIG>.

In one embodiment, the display will show a color picture with video when a customer is nearby to engage effectively, but will display a static picture or no picture when no person or object is present, allowing the unit to integrate and store energy for the next operation. In another embodiment, the information displayed is adapted to a nearby consumer based on anonymous identification of needs. For example, if a mobile device carried by a person indicates that they have poor eyesight, the display may change to a high contrast simplified text, for example a larger font with black writing on a yellow background. In the event that multiple consumers are in proximity, the display may cycle though displays better suited to each person. The selection of display options, as before, will depend on the availability of energy. The display can change what is displayed on the screen based on the power, or power and data, received from the energy harvester <NUM>. In certain embodiments, the data may come from the infrastructure <NUM>, such as a WiFi network in a store, or from the smartphone <NUM> through its link to infrastructure <NUM> such as a WiFi or cellular network.

Referring to <FIG>, an illustration of a second embodiment of an energy harvesting system <NUM> is presented. The energy harvesting system <NUM> includes an energy harvester <NUM> that receives radio frequency signals through one or more antennas <NUM>. The energy harvester <NUM> is not limited as to how it receives RF energy and can receive radio frequency energy from multiple sources. For example, the energy harvester <NUM> can receive signals from a first smartphone 208a carried by a first person who uses first infrastructure 110a associated with a first cellular carrier. The energy harvester <NUM> also can concurrently or substantially concurrently receive signals from a second smartphone 208b carried by a second person who uses second infrastructure 110b associated with a second cellular carrier using a different frequency than the first cellular carrier. The power available to the power consuming device <NUM> from the energy harvester <NUM> can be greater than if the energy harvester <NUM> only harvested energy from signals from only one of the first or second smartphones 208a, 208b. Similarly, more or different data can be made available to the power consuming device <NUM> by the energy harvester <NUM> by harvesting radio frequency signals from both first and second smartphones 208a, 208b.

Referring to <FIG>, an illustration of a display system <NUM> powered by harvested energy is presented. In certain embodiments, the display <NUM> can change display modes based on the power received from an associated energy harvesting system (not shown, see for example <FIG> above). For example, as illustrated in the top image, the display <NUM> can display a single black and white image or a sequence of static images on the screen <NUM> when only a single smartphone <NUM> provides radio frequency signals that can be harvested for energy. When two or more smartphones 308a, 308b are present, the display <NUM> can switch to a color image or a motion video clip on the screen <NUM> using the additional received power from two or more smartphones 308a, 308b harvested by the associated energy harvesting system.

In certain embodiments, the display <NUM> can be a suitable low power display, such as an e-ink display that requires power only to change what is being displayed on the screen <NUM>, but otherwise can maintain the same displayed image on the screen <NUM> without consuming power. The e-ink display can change what is being displayed based on the amount of power received from the energy harvester system, or based on both the power and data received from the energy harvesting system. For example, the data may come from the infrastructure, such as a WiFi network in a store, or from a smartphone <NUM> carried by a person through its link to infrastructure such as a WiFi or as as illustrated in the top image, such as a cellular network.

Referring to <FIG>, an illustration of a third embodiment of an energy harvesting system <NUM> is presented. The energy harvesting system <NUM> includes an energy harvester <NUM> that receives radio frequency signals through one or more antennas <NUM>. The energy harvester <NUM> can receive radio frequency signals from multiple sources, for example a smartphone <NUM> carried by a customer or staff that is connected to infrastructure <NUM>, such as a cellular service provider. The energy harvest <NUM> can also receive radio frequency signals from alternative sources <NUM>, such as the infrastructure <NUM>. The energy harvesting system <NUM> includes a power integrator <NUM> comprising suitable electronics such as a capacitor for storing and releasing power as needed by the power consuming device <NUM>. Data can optionally be received from the energy harvester <NUM> by the power consuming device <NUM>. An example power consuming device <NUM> can include a Bluetooth LE beacon, which can adapt the power and repeat rate of the beacon based on the amount of power integrated by the power integrator <NUM> from one or more sources. For example, when multiple consumers are present, there are more sources of signals available for harvesting energy by the energy harvester <NUM> and the Bluetooth LE beacon can increase the power or repeat rate of the beacon to capture the interest of consumers nearby. Additionally, when multiple consumers are present, those consumers also may block some of the Bluetooth signal, limiting the range of the Bluetooth LE beacon, and thus increasing the power would be advantageous.

Referring to <FIG>, an illustration of a fourth embodiment of an energy harvesting system <NUM> is presented. The energy harvesting system <NUM> includes an energy harvester <NUM> that receives radio frequency signals through one or more antennas <NUM>. The energy harvester <NUM> can receive radio frequency signals from one or multiple sources. For example, the energy harvester <NUM> can receive signals from a smartphone <NUM> carried by a consumer. The energy harvesting system <NUM> can utilize a data link established with the consumer's smartphone <NUM> to request that the smartphone <NUM> use more power, for example by transmitting data via a local WiFi network or cellular network, enabling Bluetooth on the smartphone <NUM>, and so forth. In certain embodiments, the consumer can make a choice about how much power to provide to the energy harvesting system <NUM>. For example, the consumer can be presented with an additional product discount, entry into a prize winning contest, or another incentive to use more power that can be harvested by the energy harvester <NUM>. When multiple consumers are present, the requests for power can be prioritized, for example based on consumer choices or battery levels reported by the smartphones <NUM>. Advantageously, the energy harvester <NUM> can harvest RF signals from one kind of system, such as a smartphone <NUM>, and use captured energy for powering a power consuming device <NUM> that performs operations unassociated with the RF signals.

Referring to <FIG>, an illustration of a dynamic signage system <NUM> powered by harvested energy is presented. A display <NUM>, for example a display as described above for <FIG>, can dynamically change what is displayed on the screen based on whether power may be needed in one area of a facility, marked by the letter A, or a different area of a facility, marked by the letter B. For example, if the facility is a store with aisles, A might be a first aisle while B is an adjacent aisle. Consumers <NUM> can be targeted with discounts, marketing messages, or other incentives to encourage some of the consumers <NUM> to move toward one of the areas, A or B, that is in need of power.

Referring to <FIG>, an illustration of a fifth embodiment of an energy harvesting system <NUM> is presented. The energy harvesting system <NUM> includes an energy harvester <NUM> that receives radio frequency signals through one or more antennas <NUM>. The energy harvester <NUM> can receive radio frequency signals from multiple sources. For example, the energy harvester <NUM> can receive signals from a smartphone <NUM> carried by a consumer. Additionally, the energy harvesting system <NUM> can receive power from appropriately placed infrastructure <NUM>. For example, a WiFi hub can be placed at a distance d from the energy harvesting system <NUM> to increase the amount of power available to the energy harvesting system <NUM>. Infrastructure <NUM>, such as WiFi hubs, can generally be placed in any number of physical locations in a facility to provide the desired network without substantially impacting network performance. Therefore, the placement of infrastructure <NUM> can be optimized for the energy harvesting system <NUM> while having a minimal impact on a WiFi network or other systems. Energy captured from RF signals harvested from the energy harvester <NUM> can be used for powering a power consuming device <NUM>.

Referring to <FIG>, an illustration of a sixth embodiment of an energy harvesting system <NUM> is presented. The energy harvesting system <NUM> includes an energy harvester <NUM> that receives radio frequency signals through one or more antennas <NUM>. The energy harvester <NUM> can receive radio frequency signals from multiple sources. For example, the energy harvester <NUM> can receive signals from a smartphone <NUM> carried by a consumer or staff. Additionally, the energy harvesting system <NUM> can receive power from a local power source <NUM>. Energy harvested from the energy harvester <NUM> can be used for powering a power consuming device <NUM>.

The power source <NUM> can be a low cost, controllable power source for powering one or more nearby energy harvesting systems <NUM>. The power source <NUM> can be a simple transmitter of a continuous wave signal set to a frequency suitable for energy harvesting by the energy harvesting system <NUM>. For example, in certain embodiment the power source <NUM> can emit a substantially continuous unmodulated carrier signal. In related embodiments, the signal can include data modulated with the carrier signal, for example data identifying the power source <NUM> or the battery level of the power source. In certain embodiments, the power source <NUM> can be battery powered. In certain embodiments, the energy harvesting system <NUM> only requests power from the power source <NUM> as needed, for example to conserve battery power. The command data link from the energy harvesting system <NUM> to the power source <NUM> can be a direct data link, use an available infrastructure system (not shown, see for example <FIG>), or be established via a smartphone <NUM> that connects to a cellular network or local WiFi network. In certain embodiments, if the energy harvesting system <NUM> is within range of multiple power sources <NUM>, the requests for power can be based on the relative signal strength of each power source <NUM>, the respective battery levels of the power sources <NUM>, or a round-robin scheduling algorithm or other algorithms among other suitable methodologies.

Referring to <FIG>, an illustration of a seventh embodiment of an energy harvesting system <NUM> is presented. The energy harvesting system <NUM> includes an energy harvester <NUM> that receives radio frequency signals through one or more antennas <NUM>. The energy harvester <NUM> can receive radio frequency signals from multiple sources. For example, the energy harvester <NUM> can receive signals from a smartphone <NUM> carried by a consumer. Additionally, the energy harvesting system <NUM> can receive power from a phase-array RFID reader system <NUM>. Energy harvested from the energy harvester <NUM> can be used for powering a power consuming device <NUM>.

The phase-array RFID reader system <NUM> can be configured to direct power in various directions to read nearby RFID tags, for example as illustrated by beams <NUM> labeled A, B, and C. As schematically illustrated, the beam <NUM> labeled A would provide more power to the energy harvesting system <NUM> because the beam <NUM> labeled A is directed at antenna, whereas beams <NUM> labeled B and C are not directed as directly to antenna <NUM>. In general, the phase-array RFID reader system <NUM> could be configured to provide power equally in various directions or in directions based on the desired operational performance for reading RFID tags. In certain embodiments, the phase-array RFID reader system <NUM> can be configured to periodically direct energy to the beam <NUM> labeled A to provide energy to the energy harvesting system <NUM>, which may slightly degrade RFID tag reading performance. In certain embodiments, the phase-array RFID reader system <NUM> can be configured to periodically direct more energy to the beam <NUM> labeled A than to the beams <NUM> labeled Band C. In certain embodiments, the phase-array RFID reader system <NUM> can be configured to respond to requests from the energy harvesting system <NUM> to direct energy to the beam <NUM> labeled A to provide more energy to the energy harvesting system <NUM>.

The energy harvesting systems described herein illustrate example methods of harvesting energy that can be used in a multitude of different environments, such as retail environments. Energy can be harvested from any number of suitable signal sources such as mobile devices, WiFi hubs, RFID readers, local power sources, and so forth. The energy harvesting systems use data communications to control power delivery from sources based on the needs of power consuming devices. Sources can be prioritized to efficiently maximize power delivery to energy harvesting systems. Power consuming devices can change operational modes based on the power received from different sources. Among other possible uses, digital signage can be manipulated to affect the behavior of consumers to direct the consumers to areas where power may be needed.

The values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited.

Claim 1:
An energy harvesting system (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. <NUM>), comprising:
an antenna (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) configured to receive a radio frequency signal from a source (<NUM>, <NUM>, 208a, 208b, <NUM>, 308a, 308b, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>); and
an energy harvester (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) configured to receive the radio frequency signal from the antenna (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) and provide power, derived from energy in the radio frequency signal, to a power consuming device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) configured to perform one or more operations unassociated with the radio frequency signal,
characterized by the energy harvesting system (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) using data communications to control power delivery from the source (<NUM>, <NUM>, 208a, 208b, <NUM>, 308a, 308b, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) of the radio frequency signal based on the needs of the power consuming device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>).