Electromagnetic coupler arrangement

Patent metadata

Field	Value
Publication number	US-2023124090-A1
Application number	US-202017910442-A
Country	US
Kind code	A1
Filing date	Mar 11, 2020
Priority date	Mar 11, 2020
Publication date	Apr 20, 2023
Grant date	—

Abstract

A wireless electromagnetic coupler arrangement for reactive near field coupling comprising a sequential array of coupling elements which are geometrically arranged one-or two-dimensionally. By means of feeding an unmodulated wave of electromagnetic energy to each of the coupling elements and a respective associated harvester element, in an initial sensing state, an automatic selection of a single coupling element or plural coupling elements which establish a particularly strong and efficient interaction with an inlay is performed. By means of a respective feedback loop, a switchable array of resistances is used to activate the selected coupling element(s) for coupling of information to/from the loop and to de-activate the remaining coupling elements.

First claim

1 . A wireless electromagnetic coupler arrangement for providing spatial selectivity in interaction with an RF terminated planar metallic trace of arbitrary geometric shape by means of electromagnetic energy, the electromagnetic coupler arrangement comprising:
a sequential array of coupling elements shunted onto a phase compensated differential transmission line, for coupling the electromagnetic energy to the RF terminated planar metallic trace by means of reactive near field coupling; and a plurality of switchable resistor elements being included in the paths between the differential transmission line and a respective one of the coupling elements forming the array, so as to alternatively switch the resistance of the electric connection between the differential transmission line and the respective coupling element to a first or a second value, the second value being smaller than the first value, by controlling a respective switch; wherein each of the coupling elements is associated with: a respective harvester element for collecting energy that is fed from the differential transmission line; and a respective feedback loop for providing feedback from the harvester element to the respective switch for switching the resistor elements included in the respective path based on a DC voltage established at the harvester element.

2 . An electromagnetic coupler arrangement according to claim 1 , wherein an electric connection between each of the harvester elements and the differential transmission line being alternatively switchable between an electric connection with the first resistance value and an electric connection with the second resistance value, together with the electric connection between the differential transmission line and the respective coupling element.

3 . An electromagnetic coupler arrangement according to claim 1 , wherein each of the harvester elements being permanently coupled to the differential transmission line via an electric connection with the first resistance value.

4 . An electromagnetic coupler arrangement according to claim 1 , further comprising an interrogator for feeding electromagnetic energy to be coupled to the planar metallic trace.

5 . An electromagnetic coupler arrangement according to claim 4 , further comprising a balun that is electrically coupled between the interrogator and the differential transmission line, the balun forming a differential transmission line input by splitting an output of the interrogator in two parts equal in amplitude and shifted by 180° in phase.

6 . An electromagnetic coupler arrangement according to claim 4 , wherein the interrogator is configured to feed unmodulated electromagnetic energy to the coupling elements in a sensing state, the unmodulated electromagnetic energy being an RF carrier wave guided by the differential transmission line, in which the resistance is initially switched to the first value, for all coupling elements of the array.

7 . An electromagnetic coupler arrangement according to claim 6 , wherein the interrogator is configured to subsequently modulate the RF carrier as a communication signal to the coupling elements.

8 . An electromagnetic coupler arrangement according to claim 7 , wherein the interrogator is configured to feed the communication signal after a stable switching state of each of the switches has been established in view of the interaction between the unmodulated RF carrier and the RF terminated planar metallic trace.

9 . An electromagnetic coupler arrangement according to claim 1 , wherein the differential transmission line is terminated.

10 . An electromagnetic coupler arrangement according to claim 1 , wherein each of said coupling elements including a transmission line loop for interacting with the RF terminated planar metallic trace by inductive coupling, the transmission line loop being a continuous transmission line of finite length formed into a loop so that two terminals thereof approach each other and are differentially fed through the differential transmission line.

11 . An electromagnetic coupler arrangement according to claim 10 , wherein the transmission line loop has a super elliptic shape geometry in accordance with the parametric representation:
x = a cos θ 2 m   sgn cos θ                 y = b sin θ 2 n sgn sin θ a , b > 0           m , n ≥ 2         θ ∈ 0 , 2 π , wherein x and y are Cartesian co-ordinates.

12 . An electromagnetic coupler arrangement according to claim 1 , wherein each of the coupling elements comprising a transmission line pattern of an elongated spiral planar shape for interacting with the RF terminated planar metallic trace by inductive coupling, wherein the transmission line pattern of an elongated spiral shape being a continuous transmission line of finite length having an elongated spiral shape with terminals on both ends, wherein the terminals are located so that there is at least one winding of the transmission line in-between.

13 . An electromagnetic coupler arrangement according to claim 12 , wherein the continuous transmission line of finite length is wound around a fixed center point so that each winding comprises straight portions that are arranged parallel to each other.

14 . An electromagnetic coupler arrangement according to claim 1 , wherein the sequential array of coupling elements being of a one-dimensional geometric arrangement.

15 . An electromagnetic coupler arrangement according to claim 1 , wherein the sequential array of coupling elements being of a two-dimensional geometric arrangement.

16 . An electromagnetic coupler arrangement according to claim 1 , wherein the RF terminated planar metallic trace is an RFID inlay.

17 . An electromagnetic coupler arrangement according to claim 16 , adapted to encode the RFID inlay by coupling electromagnetic power thereto.

18 . An electromagnetic coupler arrangement according to claim 1 , wherein the resistance is switched to the first value when the DC voltage exceeds a predetermined first threshold value.

19 . An electromagnetic coupler arrangement according to claim 1 , wherein the resistance is switched to from the first to the second value when the DC voltage decreases below a predetermined second threshold value, the second threshold value being lower than the first threshold value.

20 . An electromagnetic coupler arrangement according to claim 1 , wherein each of the feedback loops includes an inverting operational amplifier.

21 . An RFID printer/encoder comprising an electromagnetic coupler arrangement according to claim 1 .

Assignees

• Sato Holdings Kk

Inventors

• Frank Markus

Classifications

• G06K7/0008

  General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer · CPC title

• G06K17/0025 Primary

  the arrangement consisting of a wireless interrogation device in combination with a device for optically marking the record carrier · CPC title

• G06K7/10198 Primary

  setting parameters for the interrogator, e.g. programming parameters and operating modes · CPC title

• G06K7/10158

  methods and means used by the interrogation device for reliably powering the wireless record carriers using an electromagnetic interrogation field · CPC title

• G06K7/10316

  using at least one antenna particularly designed for interrogating the wireless record carriers (antennas in general H01Q1/22) · CPC title