Granted patent
High-Q and over-coupled near-field RFID reader antenna for improved tag read range
- Number
- 10102697
- Published
- 2018-10-16
- Filed
- 2015-10-31
- Assignee
- Disney Enterprises, Inc.
- Inventors
- Sample; Alanson
- CPC
- G07C9/00309; G06K19/07762; G06K19/0723; G07C9/28; G06K7/10415; G06K7/10148; G06K7/10366
- Verdict
- Medium Hardware
- Source
- Google Patents · FreePatentsOnline
The keeper's note
RFID reader antenna hardware (wearable interaction).
Abstract
An RFID system in which at least one of the RFID tag antenna and the RFID reader antenna has an impedance matching network associated therewith in order to better match the impedances of the two antennas. This impedance matching places the antennas into an over-coupled regime once they are within a reasonable distance of each other (e.g., 2 to 50 mm). It also increases the Q-factor of the improved antenna, which can greatly increase the range at which the RFID reader can read the RFID tag. This improved RFID system may be used in any of a variety of application, including operating a door lock mechanism.
Background
BACKGROUND(1) The use of RFID (Radio Frequency Identification) technology is very common in the modern day world. One specific such use is in door lock mechanisms (such as for individual hotel rooms), in which case the door lock may include an RFID reader to detect the proximity of a device worn or held by a hotel guest and unlock the door. Problems with unlocking doors can occur due to challenging ergonomics related to door jams and door handles, due to the short read range of the RFID reader, and/or due to less than optimal performance by the RFID reader. It is desirable to increase the success rate of unlocking doors when hotel guests have their device within a reasonable proximity of the door lock mechanism.(2) Many forms of RFID make use of electromagnetic induction between a pair of coils (loop antennas), one typically located in an RFID reader and one typically located in an RFID tag. One class of RFID technology is known as Near Field Communication (NFC) in which a pair of devices establish radio communication when they are brought to within a certain minimum distance of each other (e.g., 10 cm or less). NFC devices may typically operate at an RF frequency of 13.56 MHz. Other RFID frequencies may be in the range of 125 kHz, 433 MHz, 866.5 MHz, 915 MHz, and in the microwave frequencies, to name a few.(3) One parameter of an antenna and associated circuit is known as a quality-factor (or Q-factor). It is a dimensionless quantity that describes how under-damped an oscill