US 12,244,364 B2
Variable-Q antenna coil circuit for RFID applications
Gui-Yang Lu, Upland, CA (US); and Peter Troesch, Laguna Niguel, CA (US)
Assigned to AVID Identification Systems, Inc., Norco, CA (US)
Filed by Avid Identification Systems, Inc., Norco, CA (US)
Filed on Aug. 14, 2023, as Appl. No. 18/233,824.
Application 18/233,824 is a continuation of application No. 17/073,005, filed on Oct. 16, 2020, granted, now 11,728,847.
Application 17/073,005 is a continuation of application No. 16/811,374, filed on Mar. 6, 2020, granted, now 10,812,148, issued on Oct. 20, 2020.
Prior Publication US 2024/0039581 A1, Feb. 1, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. H04B 5/77 (2024.01); H01Q 1/22 (2006.01); H01Q 7/00 (2006.01); H04B 5/26 (2024.01); H04B 5/72 (2024.01)
CPC H04B 5/77 (2024.01) [H01Q 1/2208 (2013.01); H01Q 7/00 (2013.01); H04B 5/26 (2024.01)] 15 Claims
OG exemplary drawing
 
1. An RFID system, the system comprising:
a transponder, wherein the transponder has an RFID circuit with a resonant antenna coil circuit with a variable Q factor, and the resonant antenna coil circuit includes a variable resistive element;
a reader with an AC power source that is configured to drive the resonant antenna coil circuit; and
a controller that is in communication with the antenna coil circuit and the AC power source, wherein the controller is programmed to:
modulate the AC power source to cause the RFID circuit to send information to and receive information from the transponder; and
dynamically adjust the variable Q factor of the resonant antenna coil circuit from a first value to a second value based on at least a subset of command data, a signal strength, signal timing, and distance between the transponder and the reader while the reader and the transponder are in communication with each other.