RFID TAG FOR HARSH ENVIRONMENT INDUCTIVELY COUPLED IN DOUBLE LOOP

Abstract

The invention relates to an IDRF label for use in aggressive environments. The IDRF label (1) according to the invention comprises a UIF-SIF (2) antenna made of an electrically conductive textile, electrically insulated, embroidered on a textile backing, an IDRF transponder (3) and a textile substrate (4) and the UIF-SIF antenna (2), the whole assembly being sealed by hot-dipping a second textile substrate, wherein the UIF-SIF (2) antenna has a central loop formed by a loop (5) by which it inductively couples with the encapsulated IDRF transponder 3.

Claims

1. An RFID tag (1) for use in harsh enviroments comprising an UHF-SHF antenna (2) made from a continuous electroconductive textile thread, electrically insulated, embroided on textile substrate, an RFID transponder (3) and a substrate of textile material (4) on which the RFID transponder (3) and the UHF-SHF antenna (2) are placed, the whole assembly being sealed by hot-dipping of a second textile substrate, characterized in that the UHF-SHF antenna (2) has a central zone formed by a double loop (5) by which it inductively couples with the encapsulated RFID transponder (3).

2. The RFID tag (1) according to claim 1, characterised in that the UHF-SHF antenna (2) is made of an electroconductive textile thread, electrically insulated, by continuous embroidering, starting from one end to the other, and has simple loops in each extremity, and in the central area a double loop (5) consisting of a first loop with a smaller diameter, followed by a second concentric loop with a larger diameter.

3. The RFID tag (1) according to claim 1, characterized in that the UHF-SHF antenna (2) does not show electrical contacts in the crossing points (C and D) in the construction of the simple loops located at the extremities nor in the crossing points (A and B) by which the central loop (5) is formed.

4. The RFID tag (1) according to claim 1, characterized in that the UHF-SHF antenna (2) is made by cotinuous embroidering of the elctroconductive textile thread in the form of two open loops disposed in a upper plane in relation to the longitudinal direction and two open loops disposed in a lower plane in relation to the same longitudinal direction.

5. The RFID tag (1) according to claim 4, characterized in that, in the central area, the upper plane loop (P) has a smaller diameter than the loop (Q) from the lower plane, the transponder (3) being fixed and centered on the loop (P) in the upper plane, and the loop (Q) from the lower plane will overlapp the loop (P)) from the upper plane by bending over said longitudinal direction, so that the double loop (5) is created having the transponder (3) inside it.

Description

[0036] The present invention proposes for the UHF-SHF antenna an electroconductive yarn made of metallic stainless steel wire that resists the action of oxidizing agents. By using the electroconductive textile wire to make the UHF-SHF antenna, due to its flexibility, the electroconductive textile thread allows for the realization of geometries impossible to achieve with an electrically isolated metal wire. It is possible to make very small radius curves without creating mechanical stresses in the tag structure. Also the UHF-SHF antenna made of electroconductive textile thread is very discreet and does not feel, it naturally integrates into the textile material of the product it identifies.

[0037] Other features and advantages of the present invention will become more apparent from the following detailed description, given in connection with the accompanying drawings, in which:

[0038] FIG. 1 shows a schematic view of the double-loop RFID tag according to a first embodiment of the invention;

[0039] FIG. 2 shows a the double loop in detail according to the first embodiment of the invention;

[0040] FIG. 3 shows a schematic view of the double-loop RFID tag according to a second embodiment of the invention;

[0041] The UHF-SHF antenna 2 has a particularly innovative geometry characterized in that it has in the central region a double loop 5 through which an efficient inductive coupling with the encapsulated RFID transponder 3 is provided, thereby obtaining an electromagnetically efficient RFID tag.

[0042] The double loop 5 also allows for a small, discreet and easy-to-integrate RFID tag even in small-sized textile articles.

[0043] The RFID passive UHF-SHF antenna can be made in two variants FIG. 2 and FIG. 3. In the first embodiment, FIG. 2, the electroconductive textile thread is electrically insulated and allows the thread overlapping at certain points (A, B, C, D) without electrical contact. For the second embodiment, FIG. 3, the UHF-SHF antenna geometry allows the use of a non-insulated electroconductive textile thread. Both variants are embroidered.

[0044] In the first embodiment, FIG. 2, the double loop 5 of the UHF antenna 2 through which the inductive coupling with the encapsulated RFID transponder 3 is made, has created an UHF antenna with efficient power transfer and information integrity, with substantially reduced design dimensions. There is no electrical contact at points A, B, C, and D.

[0045] In the second embodiment of the UHF-SHF antenna, FIG. 3, the drawing of the embroidery is made so that the electroconductive textile thread is continuously embroidered without crossings in its path. [0046] After embroidering, by bending over the dotted line and overlapping the two P and Q loops, a double loop (5) will form. The loop P has a smaller diameter than the Q loop. It is noted that, after bending and overlap, the currents in the two loops have the same direction, contributing together to an efficient inductive coupling. Prior to bending between the two loops P and Q, the encapsulated transponder (3) will be fixed with adhesive on the loop P. After folding and overlapping the encapsulated transponder (3) will be secured between the two loops P and Q.

[0047] The present invention is complementary to patent No. a 2016 00791, which proposed an RFID Transponder designed to operate in aggressive environments. The RFID transponder was described as being designed to be used both independently for RFID applications for which the reading range is in centimeters and with a UHF-SHF antenna for RFID applications for which the reading range is of meters order.

[0048] The design of this tag by embedding in its structure the encapsulated transponder 3, object of the patent a 2016 00791, overcomes the problems created by the dimensional discrepancies between tiny integrated cicuits and the antennas, they are galvanically connected, which require the use of expensive technologies (wire bonding) or inadequate to the harsh environment of industrial laundry (bonding with conductive adhesives).

[0049] The tag design looks for a straight measure relative to the dimensions of the objects it identifies and the size of the tag. It does not fall into excessive miniaturization when it is not necessary.

[0050] A maximal design is proposed for the maximum achievable design with the currently available components, keeping the measure. [0051] transponder with a minimum number of galvanic contacts, equal to the number of active, integrated circuit pins, robust galvanic contacts using an integrated circuit in SOT323 package, welded in the cheap and mature SMT technology, at the near-field antenna terminals, encapsulated and thus protected from the harsh environment of industrial laundry, [0052] inductive coupling between encapsulated transponder (3) and UIF-SIF antenna (2), [0053] the homogeneity of the components of the UIF-SIF antenna (2)textile substrate and the antenna, both of textile material, [0054] substantially reduced length of the tag by using the double loop of the UHF-SHF antenna. [0055] a tag born and not made for the textile world by the materials used (textile thread on a textile substrate), and the methods of making (embroidering the textile thread on the textile substrate).

TABLE-US-00001 Referin e bibliografice Brevet citat Data inregistrarii Data publicrii Solicitant Titlul EP 2405054 A1 07 lulie 2010 11 lanuarie 2012 Datamars Textile item SA (CH) identification tag DE 102007026720 06 lunie 2007 11 Decembrie Bielomatik Chip module for an A1 2008 RFID system US 20090079574 19 Septembrie 26 Martie 2009 Noriyuki Rfid tag A1 2008 WO 2013128299 02 Martie 2012 06 Septembrie Usta Enhanced antenna A1 2013 structure for RFID tags