JP2015046729A - Antenna for ic tag and ic tag using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an IC tag where antennas 10 and 10 are disposed on right and left parts of a chip connection part 20 capable of accurately reading out the IC tag even in a state where a plurality of the IC tags are proximately placed in parallel or stacked with each other.SOLUTION: Each of right and left antennas 10 and 10 is formed in a rectangular loop shape where a right and left direction of a chip connection part 20 is a long side direction, and each one long side of the antennas 10 and 10 is formed in a meandering shape.

Description

  The present invention relates to an antenna used for an IC tag and an IC tag using the antenna.

  In general, UHF (Ultra High Frequency) band IC tags have advantages such as the length of communication distance and batch reading performance, and are used in various applications.

  Conventionally, a dipole antenna is well known as an antenna for UHF band IC tags. Dipole antennas having a rectangular flat plate connected to the left and right lines of an IC chip (see, for example, Patent Document 1) and rectangular loops (see, for example, Patent Document 2) are known. .

  Particularly, a half-wave dipole antenna suitable for practical use is easy to use and widely used because the size of the antenna is about several cm to 10 cm.

  The input impedance of the half-wave dipole antenna is theoretically 73 + j43 [Ω], but the actual IC tag antenna has an IC chip specific input impedance (for example, the input impedance of the Impinj MONZA4 chip is SINGLE PORT 11 + j143Ω (915 MHz) is required for connection.

  For this reason, practical products are designed to achieve matching by taking into consideration the antenna shape, line width, line material, substrate material, and the like.

  These antennas, together with the IC chip, constitute an IC tag that can be read and written wirelessly.

JP 2007-31955 A JP 2009-213009 A

  By the way, the attachment target of the IC tag is thin as in the case where, for example, an IC tag that records information of each stored document is attached to a clear file that is stored on a shelf (hereinafter referred to as parallel) or stacked. In addition, when a plurality of parallel or stacked, information is read from the IC tags in a state in which the plurality are approached in parallel or stacked.

  In the case of an IC tag using the conventional antenna, when a plurality of IC tags are read using a reader in a state where a plurality of IC tags are close to each other in parallel or stacked as described above, they are particularly sandwiched between them. There is a problem that the alignment of the IC tag is disturbed and reading is likely to occur.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide an IC tag that can be read accurately even in a state where a plurality of them are close to each other in parallel or stacked. To do.

In order to solve the above-described problems, the present invention provides an IC tag antenna formed on the left and right sides of an IC chip connecting portion.
In both the left and right sides, the left and right direction of the IC chip connection part is the long side direction, a rectangular loop shape composed of fine wires with a width of 1 mm to 3 mm, and one long side meanders, and the antenna is constant. The present invention provides an antenna for an IC tag, characterized in that it is configured with a line width of

The present invention is formed symmetrically on the left and right of the IC chip connection portion,
It is point-symmetrically formed on the left and right of the IC chip connection part,
Is included as a preferred embodiment thereof.

  The present invention also provides an IC tag comprising an IC chip connected to the IC chip antenna.

  The IC tag of the present invention provided with the antenna of the present invention can be read with high accuracy even when a plurality of IC tags are stacked close to each other.

It is a front view which shows the antenna and IC tag of this invention. 6 is a graph showing return loss characteristics obtained by simulation of Example 1. FIG. It is explanatory drawing of the comparative example 1, (a) is a front view which shows the IC tag used by the comparative example 1, (b) is a graph which shows the return loss characteristic obtained by the simulation of the comparative example 1. FIG. It is explanatory drawing of the comparative example 2, (a) is a front view which shows the IC tag used by the comparative example 2, (b) is a graph which shows the return loss characteristic obtained by the simulation of the comparative example 2. FIG. It is explanatory drawing of the comparative example 3, (a) is a front view which shows the IC tag used by the comparative example 3, (b) is a graph which shows the return loss characteristic obtained by the simulation of the comparative example 3. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings referred to below, the same reference numerals denote the same components.

  As shown in FIG. 1, the antennas 10a and 10b of the present invention are used for a wireless IC tag, and are provided on the left and right of an IC chip connecting portion 20 provided in the center. A matching circuit 21 is connected to the IC chip connection unit 20. The antennas 10 a and 10 b, the IC chip connection unit 20, and the matching circuit 21 are configured by conductive layers stacked on the sheet-like insulating substrate 1.

  The antennas 10a and 10b have a rectangular loop shape with the left-right direction of the IC chip connecting portion 20 as the longitudinal direction, and one long side meanders on both the left and right sides. In other words, when one of the long sides has a meander shape, when a radio wave is received at the short side on the tip side, a propagation delay occurs in the current passing through the meandering long side and the current passing through the long side of the straight line. . In the present invention, when the antenna receives a radio wave, the propagation delay results in wavelength shortening. That is, it is considered that the presence of a line in which propagation delay occurs and a line in which propagation delay does not occur realizes a wide band of the antenna and improves the performance of an IC tag using the antennas 10a and 10b. In addition, the loop is formed by a thin line having a width of 1 mm or more to 3 mm or less, and the central part is omitted, so that when a plurality of IC tags having the antennas 10a and 10b are arranged close to each other in parallel or stacked, adjacent ICs It is considered that the capacitor component generated between the antennas 10a and 10b of the tag is suppressed to be small, so that the occurrence of the alignment disorder of the IC tag using the antennas 10a and 10b is suppressed and the reading performance is improved.

  As shown in FIG. 1, the meandering long side in the present invention is not only the long side on the same side of the left and right antennas 10a and 10b, but may be on the opposite side, and the left and right antennas 10a and 10b A symmetrical shape or a point-symmetric shape is preferable.

  Examples of the conductive layer that forms the antennas 10a and 10b, the IC chip connection portion 20, and the matching circuit 21 include thin film layers of metals such as gold, silver, copper, aluminum, zinc, nickel, tin, and alloys containing these, A conductive ink in which the metal particles are added to an ultraviolet curable resin, a coating layer of nano silver ink in which silver particles pulverized into nano sizes are converted into ink, or the like can be used. Further, in order to form the antennas 10a and 10b, the chip connection portion 20, and the matching circuit 21 having predetermined shapes, an etching method, a transfer method, a printing method, or the like can be used.

  Examples of the material of the insulating substrate 1 include PET (polyethylene terephthalate), polyimide, polyester, foamable polyester, polyolefin, polylactic acid, polyamide, polyesteramide, polyether, polystyrene, polyphenylene sulfide, polyether ester, polyvinyl chloride. , Polyacrylic acid ester, methacrylic acid ester, coated paper, art paper, synthetic paper and the like. In order to facilitate attachment, an adhesive layer can be formed on the surface where the antennas 10a and 10b are not formed.

  The IC tag according to the present invention is provided with an IC chip 30 by being electrically connected to an IC chip connecting portion 20 connected to the antennas 10a and 10b, as indicated by broken lines in FIG. 1, and using a reader / writer. Wireless information writing and reading can be performed. The IC tag can be used for distribution process management, document and product storage management, factory process management, and the like. In particular, the IC tag of the present invention can be read with high accuracy even in a state where a plurality of IC tags are approached and stacked, and therefore, it is suitable to be provided on a thin article such as a clear file.

<Example 1>
Using electromagnetic field analysis software, a simulation was performed on the assumption that reading is performed in a state where five IC tags having the following conditions are overlapped at intervals of 1 mm, and a graph showing return loss characteristics was obtained.

(1) Antenna shape Shape shown in FIG. 1 (left and right antennas are symmetrical)

(2) Antenna dimensions Long side length L ₁ = 33 mm
Short side length L ₂ = 14 mm
Overall length L ₃ = 86mm
Line width W of each side = 2mm
Meandering depth D = 5mm

(3) Antenna material Nano silver ink

(4) Insulating base material PET

(5) Resonance point FIG. 2 shows a graph showing the return loss characteristics obtained as a result of the simulation. A to E in FIG. 2 indicate the positions of the superimposed IC tags, and the overlapping was performed in the order of A / B / C / D / E. Position A is a white circle plot, position B is a white triangle plot, position C is a white square plot, position D is a black triangle plot, and position E is a black circle plot. Show. The positions A to E are the same in FIGS. 3B, 4B, and 5B.

  2, 3 (b), 4 (b), and 5 (b), the horizontal axis represents frequency, the vertical axis represents return loss, and the graph shows the return loss characteristics of the IC tag antennas at positions A to E. ing.

  In the graph showing the return loss characteristics, since the resonance points (peak values) of the five antennas are gathered around 660 MHz to 700 MHz, all the five antennas can be read.

<Comparative Example 1>
A graph showing the return loss characteristic was obtained in the same manner as in Example 1 except that the assumed antenna was under the following conditions and the interval between the overlapped antennas was 2 mm. The materials of the antenna and the insulating base material were the same as in Example 1. In FIG. 3A, 1 is an insulating substrate, 10a and 10b are antennas, 20 is an IC chip connecting portion, 21 is a matching circuit, and 30 is an IC chip.

(1) Antenna shape The shape shown in FIG. 3A (the left and right antennas are symmetrical)

(2) Antenna dimensions Long side length L ₁ = 33 mm
Short side length L ₂ = 14 mm
Overall length L ₃ = 86mm
Line width W of each side = 2mm

(3) Antenna material Nano silver ink

(4) Insulating base material PET

(5) Resonance point As shown in FIG. 3B, since the peak values of the five antennas are gathered around 1050 MHz to 1150 MHz, all the five antennas can be read. While the return loss value of the value is around −14 dB, the comparative example 1 is degraded to −10 dB or more, so the reading performance is inferior to that of the first example.

<Comparative example 2>
A graph showing the return loss characteristic was obtained in the same manner as in Example 1 except that the assumed antenna was under the following conditions and the interval between the overlapped antennas was 2 mm. In FIG. 4A, 1 is an insulating substrate, 10 is an antenna, 20 is an IC chip connecting portion, 21 is a matching circuit, and 30 is an IC chip.

(1) Antenna shape The shape shown in FIG. 4A (the left and right antennas are symmetrical)

(2) Antenna dimensions Long side length L ₁ = 33 mm
Short side length L ₂ = 14 mm

(3) Antenna material Nano silver ink

(4) Insulating base material PET

(5) Resonance point As shown in FIG. 4B, the antennas at positions A, B, D, and E have peak values at frequencies from 1100 MHz to 1150 MHz and return loss values from -10 dB to -14 dB. However, since the return loss value of the antenna at position C is around −6 dB and is greatly degraded from the peak values of other antennas, the reading accuracy is inferior.

<Comparative Example 3>
A graph showing the return loss characteristics was obtained in the same manner as in Example 1 except that the assumed IC tag had the following conditions. In FIG. 5A, 1 is an insulating substrate, 10 is an antenna, 20 is an IC chip connecting portion, 21 is a matching circuit, and 30 is an IC chip.

(1) Antenna shape The shape shown in FIG. 5A (the left and right antennas are symmetrical)

(2) Antenna dimensions Long side length L ₁ = 33 mm
Short side length L ₂ = 14 mm
Overall length L ₃ = 86mm
Indentation width L ₄ = 2mm

(3) Antenna material Nano silver ink

(4) Insulating base material PET

(5) Resonance point As shown in FIG. 5 (b), the resonance points of the antennas at positions B, C, and D are not clearly shown. Inferior.

  1: Insulating substrate, 10a, 10b: Antenna, 20: IC chip connection part, 21: Matching circuit, 30: IC chip

In order to solve the above-described problems, the present invention provides an IC tag antenna formed on the left and right sides of an IC chip connecting portion.
Left both left and right directions of the IC chip connecting section becomes long side direction, constitute a rectangular loop width is composed of the following thin line 3mm from above 1 mm, and wherein Tei Rukoto least one of the long sides meanders An IC tag antenna is provided.

The present invention is that it is formed in line symmetry on the left and right of the IC chip connecting section,
It is point-symmetrically formed on the left and right of the IC chip connection part,
Is included as a preferred embodiment thereof.

Claims (3)

In the IC tag antenna formed on the left and right of the chip connection part,
An antenna for an IC tag, characterized in that both left and right have a rectangular loop shape in which the left and right direction of the chip connecting portion is the long side direction, and one of the long sides meanders.   2. The IC tag antenna according to claim 1, wherein the antenna is formed symmetrically on the left and right of the chip connecting portion.   An IC tag comprising an IC chip connected to the antenna according to claim 1.

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