The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 23, 2021
Filed:
Dec. 12, 2018
Square, Inc., San Francisco, CA (US);
Haipeng Yan, Whitby, CA;
Emad Bidari, Toronto, CA;
Bertram Leesti, Toronto, CA;
Afshin Rezayee, Richmond Hill, CA;
Square, Inc., San Francisco, CA (US);
Abstract
A system for sensing a proximity of a near field communication (NFC) device includes an NFC reader that communicates with a remote NFC device through load modulation. The NFC reader transmits a wireless carrier signal from an antenna, and the remote NFC device modulates such carrier signal by changing its internal impedance in order to transmit data to the NFC reader. The NFC reader has at least one antenna for receiving the modulated signal. This antenna is coupled to circuitry that measures a spectrum of the received signal and identifies a resonant frequency of the NFC device based on the measured spectrum. Such circuitry also determines the signal's amplitude at such resonant frequency and precisely estimates the distance of the remote NFC device from the reader based on such amplitude. By estimating the precise distance of the remote NFC device from the reader, the location of the remote NFC device relative to the reader can be precisely determined, and this information may be used to operate the NFC reader more efficiently.