Charging long-range radio frequency identification tags

A method for charging long-range radio frequency identification tags comprising:

• directing by a first transmitter, a first energy beam to an energy location;
• directing by a second transmitter physically separate from the first transmitter, a second energy beam to the energy location;
• storing by a tag at the energy location, a received energy from the energy location;
• sensing with the stored received energy, a sensor data;
• transmitting with the stored received energy, the sensor data from the tag to a reader, after a period from when the tag is at the energy location;
• aligning at the energy location by a controller, a first frequency of the first energy beam with a second frequency of the second energy beam, and at least one of a first phase and a first polarity of the first energy beam with a respective second phase and a respective second polarity of the second energy beam to maximize an energy level at the energy location in response to a device response of the tag;
• and
• further comprising charging a capacitor of the tag to an operating voltage level in response to the tag receiving the received energy, wherein the period equals a charging time to charge the capacitor to the operating voltage level measured by a voltage monitor connected to the capacitor,
• further comprising transmitting by the tag, a default content of a memory of the tag, while the capacitor is not charged to the operating voltage level, and sensing and transmitting by the tag, the sensor data after the capacitor is charged to the operating voltage level, and
• wherein the default content of the memory includes one or more of a cleared data value representing a cleared condition of the memory, a first semaphore representing an uncharged status of the capacitor, a second semaphore representing whether the sensor data has been sensed since last transmitted, a timestamp value representing a time when the memory was cleared, and a received signal strength indicator representing a signal strength of the received energy.

A system for charging long-range radio frequency identification tags comprising:

• a plurality of physically separated transmitters, each transmitter configured to direct a respective energy beam to an energy location;
• a tag at the energy location, the tag configured to store a received energy from the energy location, to sense a sensor data and to transmit the sensor data to a reader after a capacitor connected to the tag charges to an operating voltage level, the capacitor charged by the received energy;
• a controller configured to align at the energy location for each of the plurality of transmitters, a respective frequency, and at least one of a respective phase, and a respective polarity of each respective energy beam to maximize an energy level at the energy location in response to a device response of the tag;
• and
• wherein the tag is configured to transmit a default content of a memory of the tag, while the capacitor is not charged to the operating voltage level, and the tag is configured to sense and transmit the sensor data after the capacitor is charged to the operating voltage level, and
• wherein the default content of the memory includes one or more of a cleared data value representing a cleared condition of the memory, a first semaphore representing an uncharged status of the capacitor, a second semaphore representing whether the sensor data has been sensed since last transmitted, a timestamp value representing a time when the memory was cleared, and a received signal strength indicator representing a signal strength of the received energy.