Method and apparatus for dynamic RF power division by manipulating DC output characteristics

Abstract

In some embodiments, the RF tuning network is configured to receive an input signal via an antenna. The RF energy collector is configured to receive an output of the RF tuning network and generate a direct current (DC) output based on the received output of the RF tuning network. The load manipulator is coupled to the output of the RF energy collector and configured to transition between a first configuration and a second configuration to manipulate one or more characteristics associated with the RF energy collector such that an input impedance of the RF energy collector changes from a first input impedance to a second input impedance. The first input impedance is associated with a first distribution of RF energy, and the second input impedance is associated with a second distribution of RF energy related to the input signal to the RF energy collector.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 437,109, filed January 4, 2023, entitled "Method and Apparatus for Dynamic RF Power Splitting Through Manipulation of DC Output Properties," the disclosure of which is incorporated herein by reference in its entirety. [Background technology]

[0002] Some embodiments described in this disclosure generally relate to systems, methods, and apparatus for controlling the distribution of radio frequency (RF) power in or by an RF energy harvesting system.

[0003] Known RF switches in the characteristic impedance of an energy harvesting system can be controlled by a microcontroller or another device to control power distribution within or by the energy harvesting system. However, RF switches tend to add cost, size, and / or complexity to the system design. Known energy harvesting systems may include passive RF tuning networks used to divide power among separate components within the energy harvesting system, but the power division in such energy harvesting systems is fixed and cannot be dynamically changed. Another approach involves including multiple antennas in known energy harvesting systems, each configured with a separate harvester or load so that multiple harvesters and / or loads within the energy harvesting system can receive energy. Such an approach can increase the overall size, cost, and complexity of the system design and may require special care to avoid interference between the antennas.

[0004] Therefore, a need exists for an RF energy harvesting system that is configured to distribute RF power internally and / or externally as desired, avoiding the drawbacks of existing power distribution methods and allowing for dynamic control of RF power division. Summary of the Invention

[0005] In some embodiments, the apparatus includes an antenna, a radio frequency (RF) tuning network, an RF energy collector (harvester), and a load manipulator. The RF tuning network may be configured to receive an input signal via the antenna. The RF energy collector may be operably coupled to the RF tuning network, configured to receive an output of the RF tuning network, and configured to generate a direct current (DC) output based on the received output of the RF tuning network. The load manipulator may be coupled to the output of the RF energy collector and configured to switch between a first configuration and a second configuration to manipulate one or more characteristics associated with the RF energy collector such that an input impedance of the RF energy collector changes from a first input impedance to a second input impedance. The first input impedance may be a configuration associated with a first distribution of RF energy associated with an input signal to the RF energy collector, and the second input impedance may be a configuration associated with a second distribution of RF energy associated with the input signal to the RF energy collector. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic diagram of an energy harvesting system, according to one embodiment. [Figure 2] FIG. 2 is a schematic diagram of an energy harvesting system, according to one embodiment. [Figure 3] FIG. 3 is a schematic diagram of an energy harvesting system, according to one embodiment. [Figure 4] FIG. 4 is a schematic diagram of an energy harvesting system, according to one embodiment. [Figure 5] FIG. 5 is a schematic diagram of an energy harvesting system, according to one embodiment. [Figure 6] FIG. 6 is a flowchart of a method for recovering energy, according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] In some embodiments, the apparatus includes an antenna, a radio frequency (RF) tuning network, an RF energy collector (RF energy harvester), and a load manipulator. The RF tuning network may be configured to receive an input signal via the antenna. The RF energy collector may be operably coupled to the RF tuning network, configured to receive an output of the RF tuning network, and configured to generate a direct current (DC) output based on the received output of the RF tuning network. The load manipulator may be coupled to the output of the RF energy collector and configured to be switched between a first configuration and a second configuration to manipulate one or more characteristics associated with the RF energy collector such that an input impedance of the RF energy collector changes from the first input impedance to a second input impedance. The first input impedance may be associated with a first distribution of RF energy associated with an input signal to the RF energy collector, and the second input impedance may be associated with a second distribution of RF energy associated with the input signal to the RF energy collector.

[0008] In some embodiments, the apparatus includes an antenna, a radio frequency (RF) tuning network, an RF energy collector, and a set of one or more components configured to receive RF energy. The RF tuning network may be configured to receive an input signal via the antenna. The RF energy collector may be operably coupled to the RF tuning network and configured to receive an output of the RF tuning network and, in response to the RF energy collector having a first input impedance, generate a direct current (DC) output based on the received output of the RF tuning network. The set of one or more components may be configured to receive RF energy reflected or directed from the RF energy collector in response to the RF energy collector having a second input impedance. The DC output of the RF energy collector may be configured to switch the RF energy collector from a state having the first input impedance to a state having the second input impedance. In some embodiments, the set of one or more components may include a circuit, such as an RF device, an RF tuning network, an RF energy collector, an RF communication device, and / or a radio frequency identification (RFID) integrated circuit (IC).

[0009] In some embodiments, a method includes manipulating one or more characteristics associated with a radio frequency (RF) energy collector at a first time such that an input impedance of the RF energy collector changes from a first input impedance to a second input impedance to generate a first distribution of RF energy to the RF energy collector. The RF energy may be associated with an input signal received by the RF energy collector via an antenna operatively coupled thereto. At a second time, one or more characteristics associated with the RF energy collector may be manipulated such that the input impedance of the RF energy collector changes from the second input impedance to a third input impedance. The third input impedance may be associated with a second distribution of RF energy to the RF energy collector.

[0010] In some embodiments, an energy harvesting system may include one or more RF energy collectors, each having an input impedance related to the distribution (e.g., direction and / or reflection) of incident RF power within the energy harvesting system. The input impedance of each of the one or more RF energy collectors may be configured to change in response to changes in one or more characteristics (e.g., one or more parameters) of the energy harvesting system that includes the one or more RF energy collectors. For example, the harvester direct current (DC) output voltage, operating frequency, incident RF input power, and other parameters of the energy harvesting system may affect the input impedance of the RF energy collectors. Thus, the distribution (e.g., direction and / or reflection) of incident RF power within the energy harvesting system may be controlled by changing (e.g., manipulating) the input impedance of each of the one or more RF energy collectors by changing one or more of the system parameters, individually or in combination.

[0011] In some embodiments, the input impedance of an RF energy collector in an energy harvesting system can be modified to control the amount of RF energy directed to the RF energy collector and the amount of RF energy reflected from the input of the RF energy collector. In some embodiments, the input impedance of an RF energy collector in an energy harvesting system can be modified to reflect or direct RF power to one or more RF devices connected in parallel or series to the RF energy collector, or to reflect it back to an antenna (e.g., the antenna where the RF energy was originally received) for communication purposes (e.g., backscatter communication). In some embodiments, the systems and methods described herein enable dynamic control of RF power division by manipulating the DC output characteristics of the RF energy collector.

[0012] One or more embodiments of the RF energy collector described herein have an input impedance that can be manipulated in at least one of several ways to control the amount of RF energy received by the RF energy collector and / or the amount of RF energy reflected from the input of the RF energy collector. For example, one or more system characteristics (e.g., parameters) of an energy harvesting system including an antenna, a front-end tuning network (also referred to as an RF tuning network), and an RF energy collector can be altered to create an impedance mismatch between the antenna and the RF energy collector so that energy is reflected or directed from the input of the RF energy collector. Specifically, in some embodiments, an energy harvesting system may include a front-end tuning network configured to match the impedance of the system's antenna to the input impedance of the RF energy collector at a particular set of system parameters (e.g., frequency, input power, and / or DC load voltage) for maximum power transfer. If one or more of these system parameters are changed without changing the tuning network (e.g., without changing the RF tuning network 320 to account for changes in input impedance), an impedance mismatch between the RF energy collector and the antenna may be created, reducing system efficiency and altering the distribution of energy to the RF energy collector.

[0013] In some embodiments, the output DC operating point of an RF energy collector (e.g., a rectifier circuit), such as any of the RF energy collectors described herein, may be manipulated to manipulate the input RF characteristics (e.g., input impedance) of the RF energy collector. Thus, as another example, a load (e.g., electrically coupled to the output) of an RF energy collector in a system may be changed to control (e.g., adjust) the input impedance of the RF energy collector and therefore vary the flow of RF energy to the RF energy collector. For example, in some embodiments, the DC output of an RF energy collector in a system (e.g., an energy harvesting system) may be changed by switching (e.g., replacing, removing, and / or adding) different load devices into the system (e.g., electrical connection with the RF energy collector). Thus, in some embodiments, different loads may include a common load device. The load device may include, for example, a passive load such as one or more resistors, capacitors, and / or inductors. The load device may also include, for example, an energy storage device (e.g., a battery or solar cell) at a different voltage.

[0014] In some embodiments, one or more load devices electrically coupled to the RF energy collector may be included in the system and configured to be switched, enabled, disabled, and / or otherwise controlled (e.g., by controlling the state of one or more switches) by a controller (e.g., a digital or analog controller) configured to control the relationship between the RF energy collector and the one or more load devices based at least in part on the intended input impedance of the RF energy collector.

[0015] In some embodiments, the output voltage of an RF energy collector can also be varied by increasing or decreasing the output voltage using a direct current to direct current (DC-DC) converter (e.g., including one or more DC-DC converters in the system electrically coupled to the RF energy collector, such as the output of the RF energy collector), or by digitally controlling the output voltage present at the output of the RF energy collector using a digital-to-analog converter (e.g., included in the system and electrically coupled to the RF energy collector).

[0016] In some embodiments, an RF energy harvesting system may include an RF source (e.g., an antenna), a tuning network (also called a matching network), an energy collector, and / or a load. The load may include one or more passive components, one or more energy storage devices, one or more DC / DC converters of any type, and / or any combination thereof. The tuning network may include passive and / or active components. In some embodiments, one or more devices may be included in or coupled to the system, may use (e.g., be electrically coupled to) the same RF source, and / or may be connected in parallel, series, and / or other configurations. Each device may or may not have its own tuning network and / or load associated with it. The one or more devices may include an RF energy collector, an RF communication device, and / or an RF device such as a radio frequency identification (RFID) integrated circuit (IC). The one or more devices may include, for example, one or more RF-to-DC converters, one or more processors, one or more memories, one or more energy storage devices, one or more tuning networks, and / or any other suitable circuitry or components. For example, in some embodiments, a system such as any of the systems described herein may include an RF energy collector having its own tuning network connected in parallel with a radio frequency identification (RFID) integrated circuit (IC) having its own tuning network, both connected to a single antenna.

[0017] 1 is a schematic diagram of an energy harvesting system 100. System 100 may be identical or similar in structure and / or function to any of the systems described in this disclosure. System 100 includes an antenna 110, an RF tuning network 120, an RF energy collector 130, and a load handling assembly 140 (also referred to as a load manipulator) coupled to an output 150 of RF energy collector 130.

[0018] The load manipulation assembly 140 may include one or more components configured to manipulate one or more DC output characteristics of the RF energy collector 130 to change the input impedance of the RF energy collector 130. For example, in some embodiments, the load manipulation assembly 140 may include a set of one or more load devices configured to be selectively electrically coupled to the output 150 of the RF energy collector 130 in various combinations. As described above, in some embodiments, the load coupled to the output of the RF energy collector may be manipulated by changing which of the set of load devices is placed in electrical connection with the output 150 of the RF energy collector 130. For example, one or more load devices may be switched (e.g., replaced, removed, and / or added) into electrical connection with the output 150 of the RF energy collector 130. In some embodiments, one or more of the one or more load devices may be physically removed and / or added to the system 100 and / or physically connected to and / or disconnected from the output 150 (e.g., by a user) to change the load coupled to the output 150. In some embodiments, one or more of the one or more load devices may be switched into and / or out of electrical connection with the output 150 to change the load coupled to the output 150 without physically moving one or more of the load devices relative to the output 150, such as through switching circuitry and / or components associated with each load device and output 150 between a connected and a disconnected state. The switches may be controlled, for example, by one or more controllers and / or switches coupled to or included in the system 100 (not shown). One or more controllers and / or switches and / or load devices configured to be selectively coupled to the RF energy collector output 150 may optionally be included in or coupled to the load handling assembly 140.One or more controllers and / or switches may be configured to enable dynamic control of the power division of system 100 (e.g., relative to the input of RF energy collector 130). Each of the one or more controllers may include, for example, one or more processors (e.g., general or application-specific processors) and / or one or more circuits (e.g., application-specific integrated circuits (ASICs)). In some embodiments, the one or more processors may be configured to execute software and / or code to perform any of the functions described in this disclosure.

[0019] RF energy collector 130 may be configured to receive energy (e.g., carried by an input signal) from antenna 110 via RF tuning network 120. RF energy collector 130 may be operatively coupled to RF tuning network 120 and configured to receive the output of RF tuning network 120. RF energy collector 130 may be configured to generate a direct current (DC) output based on the received output of RF tuning network 120. For example, RF energy collector 130 may be configured to include one or more rectifying devices (e.g., RF-to-DC converters) (also referred to as rectifying circuits).

[0020] The input impedance of the RF energy collector 130 may change as a result of changing the DC output of the RF energy collector 130 (e.g., under the control of the load manipulation assembly 140). The change in the input impedance of the RF energy collector 130 may cause an impedance mismatch between the RF energy collector 130 and the antenna 110. Therefore, instead of transmitting RF energy received by the antenna 110 to the RF energy collector 130, some or all of the RF energy may be reflected back to the antenna 110, causing the antenna 110 to re-radiate the RF energy. Changing the load electrically connected to the output 150 of the RF energy collector 130 (e.g., by electrically coupling and / or decoupling one or more load devices to the output 150 of the RF energy collector 130) to change the DC output of the RF energy collector 130 may start and stop reflecting RF energy back to the antenna 110, such that the re-radiation of energy from the antenna 110 can be switched on or off. In this manner, backscatter communication can be achieved by changing the DC output of the RF energy collector 130. This approach and architecture differs from known RFID backscatter communications, which typically include a passive element coupled to the antenna that changes the impedance of the energy collector, thereby reflecting a portion of the received energy back to the antenna and allowing it to be transmitted by the antenna.

[0021] In some embodiments, the load handling assembly 140 may be configured to switch between multiple configurations. For example, each configuration may be a configuration with a different load (e.g., a set or subset of one or more load devices electrically coupled to the output 150). In some embodiments, the load handling assembly 140 may include any suitable number of configurations based on the combination of available load devices. Each configuration may be a configuration with a different set of RF energy collector 130 characteristics and / or a different input impedance of the RF energy collector 130. As described above, different input impedances of the RF energy collector 130 may be associated with different (e.g., distinct) RF energy distributions to the input of the RF energy collector 130. Thus, each configuration or load of the load handling assembly 140 may be a configuration with a particular RF energy distribution for the RF energy collector 130 (e.g., distribution to and distribution from the RF energy collector 130). In some embodiments, the first load may include at least one passive load device, energy storage device, or DC / DC converter, and the second load may include at least one passive load device, energy storage device, or DC / DC converter.

[0022] In some embodiments, for example, the load manipulation assembly 140 may be configured to switch between a first configuration and a second configuration to manipulate one or more characteristics associated with the RF energy collector 130, such that the input impedance of the RF energy collector 130 changes from a first input impedance to a second input impedance. The first input impedance may be a configuration involving a first distribution of RF energy associated with an input signal to the RF energy collector. The second input impedance may be a configuration involving a second distribution of RF energy associated with an input signal to the RF energy collector. In some embodiments, the load manipulation assembly 140 may be configured including a third configuration associated with a third input impedance and a third distribution of RF energy, a fourth configuration associated with a fourth input impedance and a fourth distribution of RF energy, etc.

[0023] In some embodiments, each distribution of RF energy associated with a set of one or more characteristics of the RF energy collector 130 and / or associated with a load electrically coupled to the output 150 of the RF energy collector 130 may be configured with a particular ratio of the amount of energy reflected by the RF energy collector 130 to the amount of energy directed toward the RF energy collector 130 (e.g., for conversion to DC and / or output via the output 150). For example, a first distribution of RF energy associated with a first set of one or more characteristics of the RF energy collector 130 may be configured with a first ratio of the amount of energy reflected by the RF energy collector 130 to the amount of energy directed toward the RF energy collector 130. A second distribution of RF energy associated with the first set of one or more characteristics of the RF energy collector 130 may be configured with a second ratio of the amount of energy reflected by the RF energy collector 130 to the amount of energy directed toward the RF energy collector 130. In some embodiments, rather than a portion being directed and a portion being reflected according to a ratio based on the input impedance of the RF energy collector 130, a particular distribution may be configured to include all of the energy directed to the RF energy collector and received by the input of the RF energy collector 130, and another distribution may be configured to include all of the energy reflected from the RF energy collector and received by the input of the RF energy collector 130.

[0024] In some embodiments, an energy harvesting system, such as any of the systems described herein, as discussed above, may include one or more controllers operably coupled to one or more switches and configured to control a load electrically connected to the output of the RF energy collector to manipulate the input impedance of the RF energy collector. As shown in FIG. 2 , for example, energy harvesting system 200 may include antenna 210, RF tuning network 220, RF energy collector 230, and load manipulation assembly 240 coupled to output 250 of RF energy collector 230 via one or more switches 265. System 200 may be identical or similar in structure and / or function to any of the systems described herein, such as energy harvesting system 100 described above. System 200 may include controller 260 operably coupled to one or more switches 265 and configured to selectively control which switch or combination of switches in the set of one or more switches of load manipulation assembly 240 is coupled to output 250 of RF energy collector 230. Controller 260 and one or more switches 265 may be identical or similar in structure and / or function to any one or more controllers and one or more switches described in this disclosure, such as those described above with respect to system 100. For example, controllers 260 may each include, for example, one or more processors (e.g., general or application-specific processors) and / or circuitry (e.g., application-specific integrated circuits (ASICs)). In some embodiments, the one or more processors may be configured to execute software and / or code to perform any of the functions described in this disclosure.

[0025] Although shown separately in FIG. 2 , in some embodiments, the load handling assembly 240 may include the controller 260 and the one or more switches 265. By way of example, in some embodiments, the controller 260 may be configured to selectively electrically couple a first load to the output 250 of the RF energy collector 230 in a first configuration of the load handling assembly 240 and to selectively electrically couple a second load to the output 250 of the RF energy collector 230 in a second configuration of the load handling assembly 240. The first configuration may be associated with a first input impedance of the RF energy collector 230, and the second configuration may be associated with a second input impedance of the RF energy collector 230. In some embodiments, the one or more switches 265 may include at least one switch configured to selectively couple one or more loads of the load handling assembly 240 to the output 250 of the RF energy collector 230, thereby switching the load handling assembly 240 between the first and second configurations. In some embodiments, the controller 260 may be operatively coupled to one or more switches 265 and configured to control the state of each switch of the one or more switches 265 to control the selective coupling of one or more loads or one or more load devices to the output 250 of the RF energy collector 230.

[0026] In some embodiments, energy harvesting systems including RF devices that use (e.g., are coupled to and receive RF energy via) the same RF source (e.g., the same antenna) may be coupled in parallel, and optionally each RF device may be associated with (e.g., coupled to and configured to receive signals from) a corresponding front-end tuning network to which it is coupled, where at least one of the devices is an RF energy collector. For example, FIG. 3 is a schematic diagram of energy harvesting system 300. System 300 includes antenna 310, RF tuning network 320, RF energy collector 330, and load manipulation assembly 340. System 300 may be identical or similar in structure and / or function to any of the systems described herein, such as energy harvesting system 100 and / or energy harvesting system 200 described above. System 300 also includes RF device 332, which may optionally be an RF energy collector (also referred to as a “second RF energy collector”) coupled to antenna 310 in parallel with RF energy collector 330 such that both RF energy collector 330 and RF device 332 can receive energy from antenna 310 (e.g., via an RF input signal). As shown, RF device 332 may optionally be associated with a dedicated RF tuning network 322 (e.g., coupled to antenna 310 via RF tuning network 322) and / or may be coupled to RF tuning network 320 to receive energy from antenna 310 (e.g., via an RF input signal) via RF tuning network 320. RF device 332 may optionally be identical or similar in structure and / or function to any of the RF devices described in this disclosure, such as any of the RF energy collectors described in this disclosure.In some embodiments, RF device 332 and RF tuning network may be considered to be included in a set of one or more components configured to receive RF energy, in addition to RF tuning network 320 and RF energy collector 330. In some embodiments, RF device 332 may include any suitable RF device or circuitry, such as an RF energy collector, an energy storage device, an RFID IC (e.g., an RFID ASIC), and / or an RFID tag. RF device 332 may include, for example, a processor, memory, and optionally, an RF transmitter, an RF receiver, and / or an RF transceiver. RF device 332 may also be configured to operate based on the received RF energy and / or use the received RF energy for communication purposes.

[0027] In response to changes in the DC output of the RF energy collector 330 (e.g., under the control of the load handling assembly 340), the input impedance of the RF energy collector 330 may change. The change in the input impedance of the RF energy collector 330 may cause an impedance mismatch between the RF energy collector 330 and the antenna 310, and between the RF energy collector 330 and the RF device 332 and / or any other RF devices included in the system, without modifying the RF tuning network 320 with the change in input impedance. The impedance mismatch may direct more or less power into the RF energy collector 330, and therefore may also direct (e.g., reflect) more or less power to the RF device 332, other devices in the system 300, and / or the antenna 310. Thus, in such a system (e.g., a system including a harvester and one or more other devices coupled in parallel and to a common antenna, such as system 300), the amount of power provided to RF devices coupled in parallel to the RF energy collector (e.g., RF energy collector 330) can be controlled by controlling the DC output of RF energy collector 330.

[0028] In some embodiments, such as any of the energy harvesting systems and / or methods described herein, modifying the input impedance of a harvester to control the distribution of energy within the system can be used to extend the battery life of one or more RF devices included in the system. In some embodiments, as shown in FIG. 4 , for example, energy harvesting system 400 may include an antenna 410, an RF tuning network 420, an RF energy collector 430 electrically connected in parallel with an RF communication device 434 (e.g., an RF backscatter device), powered circuitry 436, and an energy storage device 470. Optionally, system 400 may include a load manipulation component 440 coupled to the output of RF energy collector 430, which may be identical or similar in structure and / or function to any of the load manipulation components described herein.

[0029] The energy storage device 470 may initially be disabled and / or electrically isolated (e.g., via any suitable switching device 472) from the system 400 or the rest of the system 400 (e.g., from the RF energy collector 430), and all received RF power may be initially directed to the RF energy collector 430 (e.g., via the RF tuning network 420). In response to incident RF energy detected and / or collected by the RF energy collector 430, the energy storage device 470 may be configured to be electrically connected and / or enabled to the system (e.g., the RF energy collector 430 may “turn on” the system by connecting and / or enabling the energy storage device 470 in response to detecting and / or collecting RF energy, such as by providing energy to the energy storage device 470). Connecting and / or enabling the energy storage device 470 in the system 400 may change the output voltage of the RF energy collector 430 and change the input impedance of the RF energy collector 430. In response to a change in the input impedance of RF energy collector 430, the energy distribution to RF energy collector 430 may change such that some or all of the power received by system 400 (e.g., received via antenna 410 of system 400 and provided to the input of RF energy collector 430 by RF tuning network 420) is directed to RF communication device 434 rather than being directed to RF energy collector 430. Thus, system 400 may be configured to enable RF energy collector 430 to activate and / or provide energy to increase the stored power level in energy storage device 470 for a first period of time, and then provide (e.g., direct) energy to RF communication device 434 for a second period of time (e.g., after activating suitable switching device 472 and / or energy storage device 470 and / or during or after increasing the stored power level).Such a system 400 and method allows the system 400 to remain off to conserve battery life when there is no or insufficient RF energy, and to direct some or all of the power received by the system 400 (e.g., by the antenna 410 of the system 400) to the RF communication device 434 for communication when sufficient RF energy is present. This is accomplished using only one antenna 410 and does not require an expensive RF switch.

[0030] 4, RF communication device 434 may have an input coupled to an output of RF tuning network 420 such that RF communication device 434 can receive the output of RF tuning network 420 (e.g., at least a portion of the input signal received via antenna 410 or at least a portion of the conditioned input signal provided by RF tuning network 420 based on the input signal received via antenna 410). Optionally, in some embodiments, rather than sharing the RF tuning network 420 with RF energy collector 430, RF tuning network 420 may be the first RF tuning network 420, and RF communication device 434 may have an input coupled to an output of a second RF tuning network 422 optionally included in system 400. RF communication device 434 may be configured to receive the output of second RF tuning network 422 (e.g., at least a portion of the input signal received via antenna 410 or at least a portion of the conditioned input signal provided by RF tuning network 422 based on the input signal received via antenna 410). Each of RF tuning network 420 and second RF tuning network 422 may be identical or similar in structure and / or function to any of the tuning networks described in this disclosure.

[0031] Although illustrated and described with respect to energy storage device 470 and RF communication device 434, any suitable RF device or circuit may be coupled to the output of RF energy collector 430 and / or coupled to antenna 410 in parallel with RF energy collector 430 (e.g., via RF tuning network 420 or via a separate RF tuning network 422). For example, as an alternative or in addition to switching device 472 and energy storage device 470, system 400 may include an RF circuit or device that is activated by RF energy collector 430 (e.g., by receiving DC power from RF energy collector 430). 4 , system 400 may also include any suitable RF device (e.g., one or more energy storage devices or multiple circuits) configured to receive RF energy directed from the input of RF energy collector 430 after a change in input impedance of RF energy collector 430 caused by activation of an RF device or circuit electrically coupled to the output of RF energy collector 430. In some embodiments, RF communication device 434 and circuit 436 may be included in an RFID IC. In some embodiments, RF communication device 432, RF tuning network 422, and / or circuit 436 may be considered to be included in a set of one or more components configured to receive RF energy, in addition to RF tuning network 420 and RF energy collector 430.

[0032] In some embodiments, a harvester circuit may be used to charge an energy storage device. Once the energy storage device is fully charged, an energy harvesting system (e.g., a receiver or a system included in the receiver) including an antenna, energy storage device, and harvester may be configured to change (e.g., switch) the harvester input impedance by changing the DC output voltage as described herein to create an impedance mismatch that can reflect and re-radiate RF power (e.g., a majority of the RF power) back to the antenna. This allows the re-radiated RF energy to be used to power and / or charge other devices. Without this technology, when the energy storage device is fully charged, additional received power may be directed to a resistor, LED, or some other device included in the system to absorb excess energy and prevent overcharging of the energy storage device. By changing the harvester DC output voltage to change the harvester input impedance and create an impedance mismatch between the harvester and the antenna, excess energy may be re-radiated by the system (e.g., a receiver) and received and used by other devices (e.g., RF devices requiring that energy).

[0033] In some embodiments, the energy harvesting systems and methods described herein enable dynamic power switching between an RF energy collector and one or more other RF devices coupled in parallel, series, or other combinations and all using the same RF source (e.g., antenna) by creating an impedance mismatch between the harvester, the RF source, and any other connected RF devices. The impedance mismatch is created by taking advantage of the property of the harvester to change its RF input impedance when the DC output voltage changes. This is achieved without the need for multiple antennas, RF switches, or other complex, expensive, or bulky solutions.

[0034] In some embodiments, the systems and methods described in this disclosure enable RF backscatter communication without the need for a separate RF backscatter integrated circuit (IC) or RF switching. Backscatter communication results from an impedance mismatch between the antenna and the harvester, which is caused by changes in the DC output voltage of the harvester.

[0035] In some embodiments, multiple RF collectors can be connected in parallel, each with or without its own impedance matching or tuning network. For example, as shown in FIG. 5, system 500 may include antenna 510 and first and second RF energy collectors 530 and 531 coupled in parallel to antenna 510. Each of first and second RF energy collectors 530 and 531 may be tuned to have peak efficiency at different input power levels across a range of possible input powers. Based on the input power to system 500, any harvester (e.g., first RF energy collector 530) may have a peak efficiency, while all other harvesters connected in parallel (e.g., second RF energy collector 531 and any additional optional RF energy collectors connected in parallel but not shown in FIG. 5) may be configured to reduce the overall efficiency of system 500 by effectively utilizing the desired harvester of additional RF power. By dynamically controlling the DC outputs of the harvesters (i.e., their input impedances) as described herein, each harvester that is not in use, or that has a lower efficiency than one or more other harvesters for a particular set of input parameters related to the energy flowing to the harvester, may be configured to reflect the RF energy that it would normally receive for use by the other, more efficient harvesters. As shown, first RF energy collector 530 and second RF energy collector 531 may each have an output coupled to separate load handling assemblies 540 and 542, respectively, which may each be the same or similar in structure and / or function as the load handling assemblies described herein.

[0036] 5, in some embodiments, second RF energy collector 531 may have an input coupled to an output of RF tuning network 520 such that second RF energy collector 531 can receive the output of RF tuning network 520 (e.g., at least a portion of the input signal received via antenna 510, or at least a portion of the conditioned input signal provided by RF tuning network 520 based on the input signal received via antenna 510). Optionally, in some embodiments, rather than sharing RF energy collector 530 and RF tuning network 520, RF tuning network 520 may be first RF tuning network 520, and second RF energy collector 531 may have an input coupled to an output of second RF tuning network 522, which may be included in system 500. Second RF energy collector 531 may be configured to receive the output of second RF tuning network 522 (e.g., at least a portion of the input signal received via antenna 510 or at least a portion of the conditioned input signal provided by RF tuning network 522 based on the input signal received via antenna 510). Each of first RF tuning network 520 and second RF tuning network 522 may be identical or similar in structure and / or function to any of the tuning networks described in this disclosure. In some embodiments, second RF energy collector 532 and RF tuning network 522 can be considered to be included in a set of one or more components configured to receive RF energy, in addition to RF tuning network 520 and RF energy collector 530.

[0037] In some embodiments, a harvester of multiple RF harvesters arranged in parallel in a system tuned for a higher input power will not turn on and begin harvesting until the power input increases. Thus, as soon as a harvester turns on, it may operate a DC load electrically coupled to the other harvesters, thereby changing the impedance of all harvesters tuned for a lower input power and thus reflecting their power back to the harvester that is on.

[0038] In some embodiments, the impedance of a harvester may be set by the physical design of the harvester to resonate with an external inductor or capacitor at a particular frequency and input power level. Multiple harvesters may be electrically connected in parallel, configured to resonate with the same external inductor or capacitor at different input power levels. The harvester with the highest efficiency at a given input power level may be left on and continue harvesting, while the input impedance of the other harvesters may be set high (e.g., adjusted) by manipulating the output voltage of the other harvesters. As the input power varies, the most efficient harvester of the set of harvesters may be used, while the others may be set to a high impedance. This allows the overall system efficiency to remain high across a range of input powers while using a single external inductor or capacitor.

[0039] 6 is a flowchart of method 600. Method 600 may be, for example, a method of using or operating a system such as any of the systems described in this disclosure. Method 600 includes, in step 602, at a first time, manipulating one or more characteristics associated with a radio frequency (RF) energy collector to change an input impedance of the RF energy collector from a first input impedance to a second input impedance to generate a first distribution of RF energy to the RF energy collector, where the RF energy is associated with an input signal received by the RF energy collector via an antenna operatively coupled thereto. The first distribution of RF energy may be with the second input impedance.

[0040] In step 604, one or more characteristics associated with the RF energy collector are manipulated at a second time such that the input impedance of the RF energy collector changes from the second input impedance to a third input impedance associated with a second distribution of RF energy to the RF energy collector.

[0041] In some embodiments, the third input impedance may be equal to the first input impedance. In some embodiments, the third input impedance may be different from the first input impedance. In some embodiments, the second input impedance is greater than the first input impedance. In some embodiments, the second input impedance is less than the first input impedance. In some embodiments, the third input impedance is greater than the second input impedance and / or the first input impedance. In some embodiments, the third input impedance is less than the second input impedance and / or the first input impedance.

[0042] In some embodiments, the RF energy collector may be configured to receive an input signal from an antenna via a radio frequency (RF) tuning network, and the manipulation of the one or more characteristics at the second time may be configured to be performed without modifying the tuning network.

[0043] In some embodiments, the one or more characteristics may include at least one of a system frequency, an input power, or a DC load voltage. In some embodiments, the one or more characteristics may include a DC output, and the operation may include switching a load coupled to the output of the RF energy collector from a first load to a second load at a first time (e.g., using any of the systems, devices, or methods described herein). In some embodiments, the first load and the second load may each include one or more load devices, and switching the load from the first load to the second load may include at least one of electrically coupling the additional load device to the output of the RF energy collector or electrically isolating the load device from the output of the RF energy collector. In some embodiments, the first load includes at least one passive load device, energy storage device, or DC / DC converter. In some embodiments, the second load includes at least one passive load device, energy storage device, or DC / DC converter.

[0044] In some embodiments, the first distribution of RF energy has a first ratio of the amount of energy reflected by the RF energy collector to the amount of energy directed towards the RF energy collector, and the second distribution of RF energy is a second ratio of the amount of energy reflected by the RF energy collector to the amount of energy directed towards the RF energy collector.

[0045] In some embodiments, the second input impedance or the third input impedance matches the impedance of an RF input of a rectifier circuit (e.g., an RF energy collector or another device or circuit including a rectifier circuit) provided to the antenna. In some embodiments, changing the input impedance of the RF energy collector from the first input impedance to the second input impedance may be a configuration that creates a mismatch between the input impedance of the RF energy collector and the antenna.

[0046] In some embodiments, the manipulating may include transmitting a signal to the RF energy collector to modify one or more DC output characteristics of the RF energy collector at a first and / or second time. In some embodiments, the signal is one of a digital signal or an analog signal. In some embodiments, the signal is a communications signal. In some embodiments, the signal is configured to modify one or more RF input characteristics of the RF energy collector over time.

[0047] In some embodiments, the first distribution of RF energy to the RF energy collector may be associated with RF energy associated with the input signal that is reflected by the RF energy collector and transmitted via the antenna for backscatter communication. In some embodiments, the second distribution of RF energy to the RF energy collector may be associated with at least a portion of RF energy associated with the input signal that is reflected or directed to an RF device coupled in series or parallel to the RF energy collector. In some embodiments, the RF device may be a first RF device, and the first distribution of RF energy to the RF energy collector may be associated with at least a portion of RF energy associated with the input signal that is reflected or directed to a second RF device coupled in series or parallel to the RF energy collector. In some embodiments, the first distribution of RF energy to the RF energy collector may involve activating a circuit, and the second distribution of RF energy to the RF energy collector may involve providing energy to an RF device coupled to the RF energy collector.

[0048] In some embodiments, the RF energy collector may be a first RF energy collector and the RF device may be a second RF energy collector. In some embodiments, the second RF energy collector may be operably coupled to an antenna and configured to receive at least a portion of the input signal via the antenna.

[0049] In some embodiments, the methods, systems, and apparatuses described herein may be implemented using U.S. Patent No. 11,394,246, issued July 19, 2022, entitled "Powering Devices Using RF Energy Harvesting," U.S. Patent No. 11,245,257, issued February 8, 2022, entitled "Method and Apparatus of High Efficiency Rectification for Various Loads," U.S. Patent No. 11,418,234, issued August 16, 2022, entitled "Bi-Stable Display Tag," U.S. Patent No. 10,484,111, issued November 19, 2019, entitled "Methods, Systems, and Apparatus for Automatic RF Power Transmission and Single Antenna Energy Harvesting," U.S. Patent No. 9,768,711, issued September 19, 2017, entitled "RF-DC Power Converter," and / or U.S. Patent No. 9,768,711, issued September 19, 2017, entitled "Methods, Systems, and Apparatus for Automatic RF Power Transmission and Single Antenna Energy Harvesting," each of which is incorporated herein by reference. No. 11,368,053, issued June 21, 2022, entitled "Systems, and Apparatus for Wireless Recharging of Battery-Powered Devices," may be the same as or similar to, or may be included in, any suitable system or method (e.g., energy harvesting system or circuit) that cooperates with any suitable system, energy collection component, configuration, and / or method described in any of the above-incorporated references. Additionally, any of the components and systems (e.g., tuning networks) described in this disclosure may be the same as or similar to any component or system (e.g., tuning networks) described in any of the above-incorporated references.

[0050] As used in this disclosure, singular forms such as "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, the term "a" device is intended to mean a single device or combination of devices, and "a" device is intended to mean one or more devices, or combinations thereof.

[0051] While various embodiments of the present invention have been described above, it should be understood that they are presented by way of example only and not limitation. Where the methods described above indicate certain events occurring in a particular order, the order of the specific events may be modified. Furthermore, some of the events may be performed simultaneously in a parallel process, where possible, or may be performed sequentially as described above. While embodiments have been particularly shown and described, it will be understood that various changes in form and detail may be made. While various embodiments have been described as having particular configurations and / or combinations of components, other embodiments can have any configuration and / or any combination or subcombination of components from any of the embodiments described in this disclosure. Furthermore, while methods have been described in this disclosure with reference to specific embodiments, the methods may be performed using any suitable device embodiment described in this disclosure.

[0052] In some embodiments, a system (or any of its components) described in this disclosure (e.g., any of the controllers and / or processors described herein) may include a non-transitory computer-readable medium (which may also be referred to as a non-transitory processor-readable medium) having instructions or computer code for performing various computer-implemented operations. The computer-readable medium (or processor-readable medium) is non-transitory in the sense that it does not itself contain a transitory propagating signal (e.g., a propagating electromagnetic wave that carries information over a transmission medium such as space or cable). The medium and computer code (which may also be referred to as code) may be designed and constructed for a specific purpose or purposes. Examples of non-transitory computer-readable media include, but are not limited to, magnetic storage media such as hard disks, floppy disks, and magnetic tape; optical storage media such as compact disks / digital video disks (CD / DVD), compact disk read-only memories (CD-ROMs), and holographic devices; magneto-optical storage media such as optical disks; carrier wave signal processing modules; and hardware devices specially configured to store and execute program code, such as application specific integrated circuits (ASICs), programmable logic devices (PLDs), read-only memory (ROM), and random access memory (RAM) devices.

[0053] Examples of computer code include, but are not limited to, microcode or microinstructions, machine instructions such as those generated by a compiler, code used to generate web services, and files containing higher-level instructions executed by a computer using an interpreter. For example, embodiments may be implemented using imperative programming languages ​​(e.g., C, Fortran, etc.), functional programming languages ​​(Haskell, Erlang, etc.), logic programming languages ​​(e.g., Prolog), object-oriented programming languages ​​(e.g., Java, C++, etc.), or other suitable programming languages ​​and / or development tools. Further examples of computer code include, but are not limited to, control signals, encryption code, and compression code.

[0054] Although various embodiments have been described as having particular configurations and / or combinations of elements, other embodiments are possible having any configuration and / or combination of elements from any of the embodiments, where appropriate. Similarly, even if the methods and / or events described above indicate particular events and / or steps occurring in a particular order, the order of the particular events and / or steps may be modified unless the context clearly dictates otherwise. While the embodiments have been particularly shown and described, it will be understood that various changes in form and details may be made.

Claims

1. 1. An apparatus comprising: The antenna and a radio frequency (RF) tuning network configured to receive an input signal via the antenna; an RF energy collector operatively coupled to the RF tuning network and configured to receive an output of the RF tuning network and generate a direct current (DC) output based on the received output of the RF tuning network; a load manipulator coupled to an output of the RF energy collector and configured to transition between a first configuration and a second configuration to manipulate one or more characteristics associated with the RF energy collector such that an input impedance of the RF energy collector changes from a first input impedance to a second input impedance, the first input impedance being associated with a first distribution of RF energy associated with the input signal to the RF energy collector and the second input impedance being associated with a second distribution of RF energy associated with the input signal to the RF energy collector.

2. 2. The apparatus of claim 1, wherein in the first configuration of the load manipulator, a first load is electrically coupled to the output of the RF energy collector, and in the second configuration of the load manipulator, a second load different from the first load is electrically coupled to the output of the RF energy collector.

3. The apparatus of claim 2 , wherein the second load comprises at least a portion of the first load.

4. 3. The apparatus of claim 2, wherein the first load comprises at least one passive load device, energy storage device, or DC / DC converter, and the second load comprises at least one passive load device, energy storage device, or DC / DC converter.

5. 10. The apparatus of claim 1, wherein the load manipulator includes a controller configured to selectively electrically couple the first load to the output of the RF energy collector in the first configuration of the load manipulator and to selectively electrically couple the second load to the output of the RF energy collector in the second configuration of the load manipulator.

6. 10. The apparatus of claim 1, wherein the load manipulator includes at least one switch configured to transition the load manipulator between the first configuration and the second configuration by selectively coupling one or more loads to the output of the RF energy collector.

7. 7. The apparatus of claim 6, wherein the load manipulator comprises a controller operatively coupled to the at least one switch and configured to control a switch state of each of the at least one switch to control the selective coupling of the one or more loads to the output of the RF energy collector.

8. 2. The apparatus of claim 1, wherein the first distribution of RF energy is related to a first ratio of an amount of energy reflected by the RF energy collector to an amount of energy directed toward the RF energy collector, and the second distribution of RF energy is related to a second ratio of an amount of the energy reflected by the RF energy collector to an amount of the energy directed toward the RF energy collector.

9. The apparatus of claim 1 , further comprising an RF device coupled in series with the RF energy collector and configured to receive RF power reflected or directed by the RF energy collector.

10. The apparatus of claim 1 , further comprising an RF device coupled in parallel to the RF energy collector and configured to receive RF power reflected or directed by the RF energy collector.

11. The apparatus of claim 1 , wherein the antenna is configured to receive RF energy reflected by the RF energy collector and to transmit the reflected RF energy for backscatter communication.

12. 2. The apparatus of claim 1, wherein the load manipulator is configured to dynamically control the input impedance of the RF energy collector within a range that includes the first input impedance and the second input impedance.

13. 10. The apparatus of claim 1, wherein changing the input impedance of the RF energy collector from the first input impedance to the second input impedance creates an impedance mismatch between the RF energy collector and the antenna.

14. 2. The apparatus of claim 1, wherein the load manipulator is configured to switch between the first configuration and the second configuration to change the input impedance of the RF energy collector without making any changes to the RF tuning network.

15. The RF tuning network is a first RF tuning network, and the device comprises: a second RF tuning network operably coupled to the antenna; The apparatus of claim 1 , further comprising: a radio frequency identification (RFID) integrated circuit (IC) operably coupled to the second RF tuning network.

16. 1. An apparatus comprising: The antenna and a radio frequency (RF) tuning network configured to receive an input signal via the antenna; an RF energy collector operably coupled to the RF tuning network, the RF energy collector configured to receive an output of the RF tuning network and generate a direct current (DC) output based on the received output of the RF tuning network in response to the RF energy collector having a first input impedance; a set of one or more components configured to receive RF energy reflected or directed from the RF energy collector in response to the RF energy collector having a second input impedance, wherein a DC output of the RF energy collector is configured to be operated to switch the RF energy collector from having the first input impedance to having the second input impedance.

17. 17. The apparatus of claim 16, wherein the RF energy collector is a first RF energy collector and the set of one or more components includes a second RF energy collector.

18. 18. The apparatus of claim 17, wherein the first RF energy collector is coupled to a first load manipulator configured to manipulate the DC output of the first RF energy collector, and the second RF energy collector is coupled to a second load manipulator configured to manipulate the DC output of the second RF energy collector to change an input impedance of the second RF energy collector.

19. 17. The apparatus of claim 16, wherein the set of one or more components includes an RF device operatively coupled to the RF tuning network and configured to receive the output of the RF tuning network.

20. 20. The apparatus of claim 19, wherein the RF energy collector is a first RF energy collector and the RF device is a second RF energy collector configured to generate a DC output based on the received output of the RF tuning network and based on RF energy reflected or directed from the first RF energy collector.

21. 17. The apparatus of claim 16, wherein the RF tuning network is a first RF tuning network, and the set of one or more components includes a second RF tuning network and an RF device operably coupled to the second RF tuning network, the second RF tuning network configured to receive an input signal via the antenna, and the RF device configured to receive an output of the second RF tuning network.

22. 22. The apparatus of claim 21, wherein the RF energy collector is a first RF energy collector and the RF device is a second RF energy collector configured to generate a DC output based on the received output of the second RF tuning network and based on RF energy reflected or directed from the first RF energy collector.

23. 17. The apparatus of claim 16, further comprising a circuit operably coupled to the output of the RF energy collector and configured to be activated by the DC output generated by the RF energy collector when the RF energy collector has a first set of one or more DC output characteristics associated with the first input impedance.

24. 24. The apparatus of claim 23, wherein the RF energy collector is configured to be operated to switch to having the second input impedance by changing the RF energy collector from having the first set of one or more DC output characteristics to having a second set of one or more DC output characteristics associated with the second input impedance.

25. 25. The apparatus of claim 24, wherein the RF energy collector is configured to change from having the first set of one or more DC output characteristics to having the second set of one or more DC output characteristics in response to activation of the circuitry operably coupled to the output of the RF energy collector.

26. 17. The apparatus of claim 16, further comprising an energy storage device coupled to the output of the RF energy collector and configured to receive and store energy related to the DC output generated by the RF energy collector.

27. The apparatus of claim 16 , wherein the set of one or more components includes an RF communication device and circuitry.

28. 1. A method comprising: manipulating, at a first time, one or more characteristics associated with a radio frequency (RF) energy collector such that an input impedance of the RF energy collector changes from a first input impedance to a second input impedance to generate a first distribution of RF energy to the RF energy collector, the RF energy being associated with an input signal received by the RF energy collector via an antenna operatively coupled thereto; and at a second time, manipulating the one or more characteristics associated with the RF energy collector such that an input impedance of the RF energy collector changes from the second input impedance to a third input impedance, the third input impedance being associated with a second delivery of the RF energy to the RF energy collector.

29. 30. The method of claim 28, wherein the RF energy collector is configured to receive the input signal from the antenna through a radio frequency (RF) tuning network, and wherein the manipulating the one or more characteristics at the second time is performed without altering the RF tuning network.

30. 30. The method of claim 28, wherein the one or more characteristics manipulated at the first time are the same as the one or more characteristics manipulated at the second time.

31. 29. The method of claim 28, wherein the one or more characteristics are from a set of characteristics associated with the RF energy collector, and the one or more characteristics from the set are different if the characteristics operated at the first time are different from the set of characteristics operated at the second time.

32. 30. The method of claim 28, wherein at least one of the one or more characteristics manipulated at the first time or the one or more characteristics manipulated at the second time comprises at least one of frequency, input power, or DC load voltage.

33. at least one of the one or more characteristics manipulated at the first time or the one or more characteristics manipulated at the second time comprises a DC output; the operating includes switching a load coupled to an output of the RF energy collector from a first load to a second load at the first time.

29. The method of claim 28.

34. each of the first load and the second load includes one or more load devices; the switching of the load from the first load to the second load includes at least one of electrically coupling an additional load device to the output of the RF energy collector or electrically decoupling a load device from the output of the RF energy collector.

34. The method of claim 33.

35. 29. The method of claim 28, wherein the third input impedance is equal to the first input impedance.

36. the first load includes at least one of a passive load device, an energy storage device, or a DC / DC converter; the second load includes at least one of a passive load device, an energy storage device, or a DC / DC converter; 34. The method of claim 33.

37. the first distribution of RF energy is associated with a first ratio of an amount of energy reflected by the RF energy collector to an amount of energy directed toward the RF energy collector; the second distribution of RF energy is associated with a second ratio of the amount of energy reflected by the RF energy collector to the amount of energy directed toward the RF energy collector.

29. The method of claim 28.

38. 30. The method of claim 28, wherein the changing the input impedance of the RF energy collector from the first input impedance to the second input impedance creates a mismatch between the input impedance of the RF energy collector and an impedance of the antenna.

39. 29. The method of claim 28, wherein the second input impedance is greater than the first input impedance.

40. 29. The method of claim 28, wherein the second input impedance is less than the first input impedance.

41. 29. The method of claim 28, wherein the second input impedance matches the impedance of an RF input of a rectifier circuit associated with the antenna.

42. 30. The method of claim 28, wherein said manipulating comprises sending a signal to said RF energy collector at said first time to modify one or more DC output characteristics of said RF energy collector.

43. 43. The method of claim 42, wherein the signal is a digital signal.

44. 43. The method of claim 42, wherein the signal is an analog signal.

45. 43. The method of claim 42, wherein the signal is a communication signal.

46. 43. The method of claim 42, wherein the signal is configured to modify one or more RF input characteristics of the RF energy collector over time.

47. 30. The method of claim 28, wherein the first distribution of RF energy to the RF energy collector is associated with RF energy associated with the input signal that is reflected by the RF energy collector and transmitted via the antenna for backscatter communication.

48. 30. The method of claim 28, wherein the second distribution of RF energy to the RF energy collector is associated with at least a portion of the RF energy associated with the input signal being at least one of reflected and directed to an RF device coupled to the RF energy collector.

49. 49. The method of claim 48, wherein the RF device is a first RF device, and the first distribution of RF energy to the RF energy collector is associated with at least a portion of the RF energy associated with the input signal being at least one of reflected and directed to a second RF device coupled to the RF energy collector.

50. 30. The method of claim 28, wherein the first delivery of RF energy to the RF energy collector is associated with activating a circuit and the second delivery of RF energy to the RF energy collector is associated with providing energy to an RF device coupled to the RF energy collector.

51. 49. The method of claim 48, wherein the RF energy collector is a first RF energy collector and the RF device is a second RF energy collector.

52. 52. The method of claim 51, wherein the second RF energy collector is operatively coupled to the antenna and configured to receive at least a portion of the input signal via the antenna.

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