JP2009044246A - Antenna, and ic tag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna and an IC tag which are compact and have high transmission/reception sensitivity and transmit/receive electric waves of a UHF band. <P>SOLUTION: The antenna 11 having a conductor pattern A formed on a dielectric sheet S includes a pair of power feeding parts e1 and e2 and a plurality of transmission lines a1, b1, a2, and b2 connected to the outside of the power feeding parts e1 and e2 respectively, wherein zigzag conductor patterns a1 and b1 and zigzag conductor patterns a2 and b2 face and pass each other to form resonance circuits of two resonance frequencies in the plurality of transmission lines, and wherein loop-shaped conductor patterns g1 connected to respective power feeding parts are formed on the outside of the pair of power feeding parts e1 and e2. The IC tag is equipped with the above antenna 11 and transmits/receives electric waves in the UHF band, wherein IC chips D are mounted on the power feeding parts e1 and e2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an antenna and an IC tag that transmit and receive UHF radio waves.

  In recent years, an IC tag composed of an IC chip and an antenna has attracted attention. An IC tag transmits information stored in an IC chip by radio waves from an antenna without receiving a reader (reception device) close to a bar code or credit card, so that the reader (reception) is located at a distance. Device). Further, for example, by attaching an IC tag to a package of a product that is delivered to and displayed at a convenience store, the product can be easily identified and managed (traceability management) in the distribution process from delivery to sales. In addition to the HF band (13.56MHz), the RFID (Radio Frequency Identification) radio frequency that can be used in Japan has become available in the UHF band (952 to 954MHz) due to the April 2005 revision of the Radio Law. The UHF band radio wave has a longer communication (transmission / reception) distance than the HF band, so there is an advantage that multiple IC tags can be read and written in a wide communication area. Expansion can be expected.

  Here, the UHF band radio wave used for IC tags refers to radio waves in the frequency range of 860 to 960 MHz for UHF band radio IC tags defined in ISO / IEC 18000-6, especially in Japan. The radio wave in the frequency range of 950 to 960 MHz is assigned as the frequency for the wireless IC tag in the UHF band, and the radio wave in the frequency range of 952 to 954 MHz can be used. In this specification, a UHF band radio wave used for an IC tag is simply expressed as a UHF band radio wave.

  IC tags are used by being affixed to various products (for example, rice balls, teacups, sweets, stationery, etc.). The dielectric constant of these various products (adhesives) and containers for storing various products (adhesives) are used. There is a problem that the operating frequency of the IC tag attached to the adherend is shifted due to the influence of the dielectric constant and the communication distance is shortened. For example, radio waves have the property of shortening the wavelength among substances having a high dielectric constant. Since the dielectric constant of the adherend and the container storing the adherend varies depending on the material and shape, conventionally, the frequency is adjusted in advance according to the dielectric constant of each adherend and the dielectric constant of each adherend and container. A plurality of IC tags are prepared and attached to the adherends. For example, in a case where rice balls are placed in a container, delivered to a convenience store, and displayed on a shelf for sale, the rice balls contained in the container can be used for product management in delivery and display and sales. Two types (two frequencies) of IC tags, ie, a rice ball IC tag taken out from the container, are pasted on the rice ball package. For this reason, the area for attaching two types of IC tags must be secured in the product package, and there is a demand for further miniaturization of IC tags.

Patent Document 1 discloses an IC tag in which a coil-shaped (loop-shaped) transmission path (antenna pattern) is formed on a printed circuit board (PCB) and an IC chip is mounted on the power feeding portion (FIG. 2). reference). The antenna described in Patent Document 1 is a kind of loop antenna, and the operating frequency of the loop antenna is that the length of the antenna coil is one wavelength. For example, in order to form an antenna that transmits and receives UHF radio waves with an operating frequency of 953 MHz. Requires a loop (transmission path) having a circumference of about 315 mm, which is too large to be practical. In Patent Document 2, a half-wave dipole antenna is formed as a pattern in which two transmission lines (antenna patterns) formed in a straight line on a dielectric sheet extend in opposite directions. By deleting both ends of the antenna pattern, the operating frequency of the IC tag attached to the product (attachment) is adjusted (refer to claim 1). The antenna described in Patent Document 2 is a kind of half-wave dipole antenna, and the operating frequency of the half-wave dipole antenna is equal to a quarter wavelength because the lengths of two transmission paths (antenna patterns) are equal to each other. The total length of the dipole antenna is half the total length of the loop antenna. On the other hand, in the method of Patent Document 2, unless both end portions of the two antenna patterns are evenly deleted, impedance balance cannot be maintained, which takes time and is not preferable in terms of the appearance of the IC tag. In Patent Document 3, a half-wave dipole antenna is used as a pattern in which two transmission paths (antenna patterns) folded in a zigzag manner on a dielectric sheet extend in opposite directions. By shortening the length of the antenna pattern that is folded back in a zigzag pattern as the distance increases, the antenna is accommodated in a size of 1 inch (25.4 mm) (see claim 1). However, the antennas of Patent Documents 2 and 3 cannot maintain impedance balance unless the lengths of the two transmission paths (antenna patterns) extending in opposite directions from the power feeding unit match each other, and transmit / receive UHF band radio waves. Since the loss increases, it is difficult to further reduce the IC tag while maintaining the performance.
Japanese Patent No. 36553099 JP 2006-270766 A JP 2007-73015 A

  Accordingly, an object of the present invention is to provide an antenna and an IC tag that transmit and receive UHF band radio waves that are small and have high transmission and reception sensitivity.

  The antenna of the present invention is an antenna in which a conductor pattern is formed on a dielectric sheet, and includes a pair of power feeding units and a plurality of transmission lines connected to the outside of each power feeding unit, A resonance circuit is formed by zigzag conductive patterns facing each other and passing each other.

  According to the present invention, the power transmission unit includes a pair of power feeding units and a plurality of transmission lines connected to the outside of each of the power feeding units, and the plurality of transmission lines pass each other with the zigzag conductor patterns facing each other. A resonance circuit is formed by the reactance component (L) due to the shape (coil length) of the zigzag conductor pattern and the capacitance component (C) due to the gap (gap) between the zigzag conductor patterns, and the resonance of the resonance circuit By adjusting the frequency to the use frequency of an IC tag that transmits and receives UHF band radio waves, an antenna with high transmission and reception sensitivity is obtained. Unlike conventional antennas, in which the length of the conductor pattern is uniquely determined by the wavelength of the radio wave, the operating frequency (resonance frequency) can be set by the zigzag conductor pattern shape and the spacing between the zigzag conductor patterns. As a result, the degree of freedom in design is increased, and a smaller antenna can be realized.

  The antenna of the present invention is an antenna in which a conductor pattern is formed on a dielectric sheet, and includes a pair of power feeding units and two transmission lines connected to the outside of each of the power feeding units. A reactance component is formed by forming a zigzag conductor pattern, and a capacitance component is formed by passing the two conductor patterns facing each other. A resonance circuit is formed by the reactance component and the capacitance component. It is characterized by being.

  According to the present invention, each of the two transmission lines becomes a zigzag conductor pattern, and the two conductor patterns face each other so that the resonance circuit can be simplified, and unnecessary resonance is reduced. An antenna having high resonance frequency characteristics can be obtained.

  Here, in general, a resonance circuit refers to a parallel resonance circuit (LC parallel resonance circuit) in which the impedance (Z) is maximum when receiving radio waves, and when transmitting radio waves, the impedance (Z) is This refers to a series resonance circuit (LC series resonance circuit) that is minimal, but in the case of an antenna, it transmits and receives radio waves, including the parallel resonance circuit and the series resonance circuit, because it transmits and receives radio waves. A circuit having an optimum impedance (Z) configuration is called a resonance circuit. As a specific design method, there is an electromagnetic field simulator by an analysis method such as a finite element method analysis (FEM analysis) using a computer. The resonance sharpness (Q) of the resonant circuit is proportional to the reactance component (L) of the resonant circuit, but the radio frequency in the UHF band of RFID that can be used in Japan is as narrow as 952 to 954 MHz. The usable frequency bandwidth matches the resonance sharpness (Q) of the resonance circuit.

  In the antenna of the present invention, it is preferable that a resonance circuit having a different resonance frequency is formed in each of the pair of feeding portions. By forming resonance circuits having different resonance frequencies in the pair of power feeding portions, two types of resonance frequencies are obtained with one antenna. Conventionally, two IC tags that have been pasted on an adherend are 1 The area for attaching the IC tag is halved.

  In the antenna of the present invention, it is preferable that a linear conductor pattern is inserted between the zigzag conductor patterns. The capacitance component (C) can be finely adjusted by inserting a linear conductor pattern between the zigzag conductor patterns. Moreover, although it becomes easy to generate | occur | produce a spurious (unnecessary signal) by expanding the space | interval of the said zigzag-like conductor patterns, this spurious can be suppressed with the said linear conductor pattern.

  In the antenna of the present invention, it is preferable that a loop-shaped conductor pattern connected to each of the power feeding units is formed outside the pair of power feeding units. The loop-shaped conductor pattern is preferably formed with a plurality of loop-shaped conductor patterns. By forming a loop-shaped conductor pattern connected to each of the power supply portions outside the pair of power supply portions, the antenna impedance can be increased by increasing or decreasing the overall length of the loop-shaped conductor pattern. Can be easily adjusted to increase or decrease. Further, by using a plurality of the loop-shaped conductor patterns, the antenna sensitivity can be easily increased or decreased by increasing or decreasing the distance between the plurality of loop-shaped conductor patterns. .

  By mounting an IC chip on the feeding portion of the antenna of the present invention, a small and highly sensitive IC tag that transmits and receives UHF radio waves is realized.

  According to the antenna of the present invention, the antenna includes a pair of power feeding units and a plurality of transmission lines connected to the outside of each of the power feeding units, and the plurality of transmission paths pass each other with the zigzag conductor patterns facing each other. Thus, a resonance circuit is formed by the shape of the zigzag conductor pattern and the interval between the zigzag conductor patterns, and by adjusting the resonance frequency of the resonance circuit to the use frequency of the IC tag that transmits and receives radio waves in the UHF band. The antenna is small and has high transmission / reception sensitivity. In the pair of feeding parts, resonance circuits having different resonance frequencies are formed, so that two types of resonance frequencies are obtained with one antenna. Conventionally, two IC tags attached to an adherend are attached. One sheet can be used. By forming a loop-shaped conductor pattern connected to each of the power supply portions on the outside of the pair of power supply portions, by increasing or decreasing the overall length of the loop-shaped conductor pattern, The antenna impedance can be easily increased or decreased. By mounting an IC chip on the feeding portion of the antenna of the present invention, a small and highly sensitive IC tag that transmits and receives UHF radio waves is realized.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1A is a plan view of an antenna 1 according to an embodiment to which the present invention is applied, and FIG. 1B is a plan view of an antenna 11 according to another embodiment to which the present invention is applied. The antenna 1 (11) is a sheet-like antenna in which an antenna conductor pattern A is formed on a dielectric sheet S. Examples of the material of the dielectric sheet S include polymers such as PET (Polyethylene Terephthalate) and PEN (Polyethylene Naphthalate), and paper. Examples of the material for the conductor pattern A include gold, silver, copper, and aluminum. Examples of the method for forming the conductor pattern A include printing, vapor deposition, sputtering, and printing. For example, a silver paste is printed on a sheet S made of PET. In this case, a conductor pattern A having a line width of 0.3 mm and a gap of 0.3 mm can be formed. The conductor pattern A is composed of a pair of power feeding parts e1, e2 and four transmission paths a1, a2, b1, b2 connected to the outside of the respective power feeding parts e1, e2, and the plurality of transmission paths a1, a2 , B1 and b2 form a resonant circuit by zigzag conductive patterns facing each other and passing each other. The size of the IC tag Z1 on which the antenna 1 (11) is formed has a total length of 26 mm and a width of 18.5 mm, and its area is smaller than one inch square. A conductor pattern (flag pattern) f1 surrounding an area without an electrode is formed at the end of the four transmission lines a1, a2, b1, and b2 (the end opposite to the power feeding unit). The flag pattern f1 is a pattern in which a rectangular pattern is disposed facing each other at the same distance from the pair of power feeding portions e1 and e2, and wide directivity characteristics can be obtained. However, the flag pattern f1 is solid-coated. (The target range is all conductors), and the flag pattern f1 can be omitted.

  The transmission path a1 (a2) is folded back zigzag from the power supply part e1 (e2) to form a flag pattern f1. Further, the transmission path b1 (b2) is folded back in a zigzag shape from the power feeding part e1 (e2) to form a flag pattern f1. The transmission path a1 (a2) and the transmission path b1 (b2) have a zigzag-shaped conductor pattern that faces each other twice so that the transmission path b1 (b2) is outside the transmission path a1 (a2). Passing once and passing each other so that the transmission line a1 (a2) is outside the transmission line b1 (b2) (FIG. 1). These zigzag conductor patterns face each other and pass each other, so that the reactance component (L) due to the zigzag conductor pattern shape (coil length) and the capacitance component (C) due to the gap (gap) between the zigzag conductor patterns (C) ), And the resonance frequency Fo of the resonance circuit is matched with the use frequency Fx of the IC tag that transmits and receives radio waves in the UHF band, whereby the antenna 1 (11) having high transmission / reception sensitivity is obtained. In the antenna 1 (11), the transmission lines a1 and a2 are symmetrically arranged with the same length around the power feeding part e1 (e2), and the transmission lines b1 and b2 are symmetrically about the same length around the power feeding part e1 (e2). Therefore, the resonance frequency Fo is one, but by appropriately setting the lengths of these transmission lines a1, a2, b1, b2, the frequency of the resonance frequency Fo can be adjusted, Two types of resonance frequencies Fo1 and Fo2 can be used. The resonance frequency Fo (Fo1, Fo2) can be appropriately set as long as it is a frequency in the UHF band used for the IC tag, but the use frequency Fx is suitable for a frequency band from 860 MHz to 960 MHz.

  In the antenna 11 shown in FIG. 1B, a loop-shaped conductor pattern g1 connected to the respective power feeding portions e1 and e2 is formed outside the pair of power feeding portions e1 and e2. The line width of the loop-shaped conductor pattern g1 is 0.6 mm, and is set to be twice the line width of the four transmission lines a1, a2, b1, and b2. By forming the loop-shaped conductor pattern g1, electrical signals from the four transmission lines a1, a2, b1, and b2 can be efficiently collected, and the overall length of the loop-shaped conductor pattern g1 can be increased or decreased. By doing so, the antenna impedance can be easily increased or decreased, so that the impedance of the pair of power feeding parts e1 and e2 can be easily matched to 50 ohms. In addition, a plurality of zigzag conductor patterns a1, a2, b1, b2 connected to the power feeding portions e1, e2 are formed by forming a loop-shaped conductor pattern g1 connected to each of the power feeding portions e1, e2. The degree of freedom of arrangement becomes higher, and the antenna 11 can be easily downsized.

  FIG. 2 is a plan view of the IC tag Z1 including the antenna 11 to which the present invention is applied. The power feeding portions e1 and e2 of the antenna 11 and the signal electrode of the IC chip D are electrically connected by soldering, conductive adhesive or the like. The surface on which the IC chip D is mounted is covered (coated) with a cover member such as a polymer in a label forming process which is a subsequent process, and is protected from the outside. The cover member is preferably made of the same material as that of the dielectric sheet S from the viewpoint of the adhesion strength, but it is possible to use a different material or to omit the cover member.

(Second Embodiment)
3A to 3D are plan views of antennas 21 to 24 which are four types of embodiments to which the present invention is applied. The antenna 21 (22, 23, 24) is a sheet-like antenna in which an antenna conductor pattern A is formed on a dielectric sheet S. The conductor pattern A is composed of a pair of power feeding parts e1, e2 and four transmission paths a1, a2, b1, b2 connected to the outside of the respective power feeding parts e1, e2, and the plurality of transmission paths a1, a2 , B1 and b2 form a resonant circuit by zigzag conductive patterns facing each other and passing each other. The size of the IC tag Z2 on which the antenna 21 (22, 23, 24) is formed has a total length of 16 mm and a width of 14 mm, which is smaller in area than the IC tag Z1 of the first embodiment and about 1 in 1 inch square. / 3 area (FIG. 4).

  The transmission path a1 (a2) and the transmission path b1 (b2) are separated from the power feeding part e1 (e2) while being zigzag-folded from the power feeding part e1 (e2). The transmission path a1 (a2) and the transmission path b1 (b2) are different so that the zigzag conductor pattern is opposed five times and the transmission path b1 (b2) is outside the transmission path a1 (a2). Pass each other three times and pass each other three times so that the transmission path a1 (a2) is outside the transmission path b1 (b2) (FIG. 3). These zigzag conductor patterns face each other and pass each other, so that the reactance component (L) due to the zigzag conductor pattern shape (coil length) and the capacitance component (C) due to the gap (gap) between the zigzag conductor patterns (C) ) And the resonance frequency Fo of the resonance circuit is matched with the use frequency Fx of the IC tag that transmits and receives radio waves in the UHF band, so that the antenna 21 (22, 23, 24) having high transmission / reception sensitivity is obtained. . In the antenna 21 (22), the transmission lines a1 and a2 are symmetrically arranged with the same length around the feeding part e1 (e2), and the transmission lines b1 and b2 are symmetrically different around the feeding part e1 (e2). Therefore, the resonance frequency Fo is two kinds of resonance frequencies Fo1 and Fo2 (FIGS. 3A and 3B). Further, in the antenna 23 (24), the transmission paths a1 and a2 are arranged with different lengths symmetrically about the feeding part e1 (e2), and the transmission paths b1 and b2 are symmetrical about the feeding part e1 (e2). Since they are arranged with the same length, the resonance frequency Fo becomes two types of resonance frequencies Fo1 and Fo2 (FIGS. 3C and 3D).

  In the antenna 24 shown in FIG. 3D, a linear conductor pattern h1 is inserted between the zigzag conductor patterns a1 and b1. The linear conductor pattern h1 is an island-like conductor pattern h1 that is not connected to any transmission line, and the capacitance component (C) can be finely adjusted by changing the length of the conductor pattern h1. Moreover, spurious (unnecessary signal) is easily generated by widening the gap between the zigzag conductor patterns a1 and b1, but this spurious can be suppressed by the linear conductor pattern h1.

  In the antenna 21 (22, 23, 24), two loop-shaped conductor patterns g1 and g2 connected to the respective power feeding portions e1 and e2 are formed outside the pair of power feeding portions e1 and e2. The inner loop-shaped conductor pattern g1 is directly connected to the respective power feeding portions e1 and e2, and the outer loop-shaped conductor pattern g2 is connected to the respective power feeding portions e1 and e2 via the inner loop-shaped conductor pattern g1. Is done. The antenna sensitivity can be increased or decreased by increasing or decreasing the distance between the two loop-shaped conductor patterns (double loops) g1 and g2 (FIG. 3). Moreover, it is easy to match the impedance of the pair of power feeding portions e1 and e2 to 50 ohms.

  FIG. 4 is a plan view of an IC tag Z2 provided with an antenna 24 to which the present invention is applied. The IC chip D is mounted on the power feeding parts e1 and e2 of the antenna 24, and the signal electrode of the IC chip D and the power feeding parts e1 and e2 are electrically connected. The matching impedance is 50 ohms.

(Analysis by electromagnetic field simulation)
The frequency characteristics of the antenna were analyzed using an electromagnetic simulator. FIG. 5 is a frequency characteristic graph by electromagnetic field simulation of the antennas 11, 21, 22, 23, and 24 of the present invention. The horizontal axis of the graph represents frequency, and the vertical axis of the graph represents sensitivity. The radio wave received by the antenna reverses the direction (phase) of the electric field (charge), so the sign of the vertical axis is negative, but the antenna sensitivity increases as the absolute value level of sensitivity increases. Since the antenna 11 of the present invention has one resonance frequency Fo, the antenna sensitivity is several decibels (dB) higher than the other antennas 21, 22, 23, and 24. Further, in the antennas 21, 22, 23, and 24 of the present invention, the positions of the two resonance frequencies Fo1 and Fo2 can be appropriately adjusted by adjusting the lengths of the four transmission lines a1, a2, b1, and b2. Recognize. In the actual antenna design, the target frequency and sensitivity characteristics are designed by electromagnetic field simulation and verified by trial measurement. By feeding back these accumulated data, the design accuracy by electromagnetic field simulation is improved.

(Comparison between the conventional example and the embodiment of the present invention)
The frequency characteristics of antenna sensitivity were measured and compared with a frequency analyzer between the antenna 11 of the present invention and a conventional antenna R recently obtained from the market. The measurement apparatus and other measurement conditions are the same. FIG. 6A is an external appearance photograph of the antenna 11 of the present invention, and FIG. 6B is a photograph of a measurement screen of the antenna 11 of the present invention by a frequency analyzer. FIG. 7A is a photograph of an external appearance of the conventional antenna R, and FIG. 7B is a photograph of a measurement screen of the conventional antenna R using a frequency analyzer.

(Conventional example)
The conventional antenna R is a half-wave dipole antenna and is used in IC tags manufactured by Intermec. The external size of the conventional IC tag is 70 mm long and 14 mm wide (FIG. 7A). The absolute value level of the antenna sensitivity around the frequency of 953 MHz is about 6 dB (FIG. 7B). Further, the frequency band is wide and gentle, and it is considered that the frequency band is easily affected by noise near 850 MHz, for example.

(Example)
The external size of the IC tag Z1 on which the antenna 11 of the first embodiment of the present invention is formed is 26 mm in total length and 18.5 mm in width, which is ½ the area of the conventional example (FIG. 6A). . The absolute value level of the antenna sensitivity around the frequency of 953 MHz is about 10 dB, which is about 4 dB higher than the conventional example (FIG. 6B). Further, since the antenna 11 according to the first embodiment of the present invention has a narrow frequency band, the antenna 11 is not affected by noise near a frequency of 850 MHz, for example. By adjusting the length of each two zigzag conductor patterns connected to the outside of each power feed section and the interval at which the zigzag conductor patterns intersect, the resonant frequency can be easily adjusted without changing the outer shape of the IC tag. Can be adjusted.

  As described above, the present invention is not limited to the embodiment described above. For example, a plurality of transmission lines have been described as two zigzag conductor patterns a1 and b1 (a2 and b2), but three or more zigzag conductor patterns may be used. A plurality of antenna conductor patterns are formed on a single dielectric sheet and processed together by making the outer shape of the zigzag conductor pattern of the plurality of transmission lines into a rectangle (square) or a polygon (hexagon). In this case, a large number of IC tag antennas can be obtained without leaving any excess. Further, an omnidirectional antenna that receives radio waves from all directions of 360 degrees can be obtained by making the outer shape of the zigzag-shaped conductor pattern of the plurality of transmission lines elliptical (circular).

  The application of the antenna of the present invention is not limited to an IC tag. For example, the antenna can be used as an antenna of a radio transceiver by making a transmission frequency and a reception frequency different. Thus, it goes without saying that the present invention can be modified as appropriate without departing from the spirit of the present invention.

FIG. 1 is a plan view of an antenna according to an embodiment to which the present invention is applied. FIG. 2 is a plan view of an IC tag according to an embodiment to which the present invention is applied. FIG. 3 is a plan view of an antenna according to another embodiment to which the present invention is applied. FIG. 4 is a plan view of an IC tag according to another embodiment to which the present invention is applied. FIG. 5 is a frequency characteristic graph by FEM analysis of the antenna according to the embodiment to which the present invention is applied. FIG. 6A is a photograph of the appearance of an antenna to which the present invention is applied, and FIG. 6B is a photograph of a measurement screen of the antenna by a frequency analyzer. FIG. 7A is a photograph of the appearance of a conventional antenna, and FIG. 7B is a photograph of a measurement screen of a conventional antenna R using a frequency analyzer.

Explanation of symbols

Z1, Z2 IC tags,
1, 11, 21, 22, 23, 24 antenna,
D IC chip,
S dielectric sheet,
A antenna conductor pattern,
e1, e2 power supply unit,
a1, a2, b1, b2 transmission path (zigzag conductor pattern),
g1, g2 transmission line (looped conductor pattern),
h1 linear conductor pattern,
Fo, Fo1, Fo2 resonance frequency

Claims (7)

An antenna in which a conductor pattern is formed on a dielectric sheet,
It consists of a pair of power supply units and a plurality of transmission lines connected to the outside of each of the power supply units, and the plurality of transmission lines form a resonance circuit by zigzag conductive patterns facing each other. An antenna characterized by. An antenna in which a conductor pattern is formed on a dielectric sheet,
A pair of power supply units and two transmission paths connected to the outside of each of the power supply units are formed, and the two transmission paths each have a zigzag conductor pattern to form a reactance component. An antenna characterized in that a capacitance component is formed by passing two conductive patterns facing each other, and a resonant circuit is formed by the reactance component and the capacitance component.   The antenna according to claim 1 or 2, wherein a resonance circuit having a different resonance frequency is formed in each of the pair of power feeding units.   The antenna according to claim 1, wherein a linear conductor pattern is inserted between any of the zigzag conductor patterns.   The antenna according to claim 1 or 2, wherein a loop-shaped conductor pattern connected to each of the power feeding units is formed outside the pair of power feeding units.   6. The antenna according to claim 5, wherein the loop-shaped conductor pattern is formed with a plurality of loop-shaped conductor patterns. An IC tag comprising the antenna according to any one of claims 1 to 6, wherein an IC chip transmits and receives UHF band radio waves mounted on the power feeding unit.

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