Patent Description:
An RFID tag includes an IC chip configured to record information and an antenna connected to the IC chip. In the RFID tag, wireless communication with the reader/writer is performed by the antenna, and thereby information stored in the IC chip is read out, or information is written in the IC chip.

There has been a growing demand for miniaturizing such RFID tags in recent years, and a miniaturized RFID tag disclosed in Patent Literature <NUM> is already known, for example, as an RFID tag that meets the demand. The antenna of the RFID tag is constituted by a multilayer antenna stacked over the IC chip and integrally joined thereto. The multilayer antenna includes a base material having substantially the same outer dimensions as the IC chip, a first coil formed on the base material, a second coil stacked on the first coil via an insulation film, and a protective film protecting the second coil.

In the RFID tag of Patent Literature <NUM>, the antenna is a multilayer antenna, and therefore has a large number of turns. As a result, the RFID tag is said to be capable of improving antenna efficiency (such as the communication distance). However, no sufficient communication distance has been achieved yet by the RFID tag, and there is room for improvement.

<CIT> relates to an antenna-mounted communication IC unit suitably used for a small portable communication terminal, a non-contact IC card, and the like.

<CIT> relates to an antenna module and radio communication device.

<CIT> relates to a RFID which includes an antenna element and a feed device.

<CIT> relates to a semi-conductor device.

The present invention has been devised in view of such circumstances, and an object thereof is to provide a booster antenna capable of improving antenna efficiency with a simple configuration.

In order to solve the aforementioned problem the present invention relates to a booster antenna according to claim <NUM> or <NUM>.

Hereinafter, an RFID tag will be described based on the drawings. <FIG> shows a passive RFID tag <NUM> in which an antenna <NUM> is electrically conductively mounted along the outer peripheral edges on the upper surface of a package (an insulating layer made of resin) of an IC chip <NUM> via an insulating layer <NUM>.

The IC chip <NUM> has a substantially square shape in plan view. The IC chip <NUM> may also have a shape such as a circular, elliptical, or polygonal shape.

The IC chip <NUM> of <NUM> square (length <NUM> × width <NUM>) to <NUM> square (length <NUM> × width <NUM>) can be used, and the IC chip <NUM> of <NUM> square (length <NUM> × width <NUM>) is used in this embodiment.

The IC chip <NUM> includes connection terminals 5A, 5B, 5C, and 5D provided inside the outer peripheral edges at the four corners.

Of the four connection terminals, the two connection terminals 5A and 5B disposed on the upper side of the page in <FIG> are connected to the antenna. More specifically, one end of the antenna <NUM> is connected to the input and output terminal 5A on one side (on the upper left side of the page in <FIG>), and the other end of the antenna <NUM> is connected to the input and output terminal 5B on the other side (on the upper right side of the page in <FIG>). Of the four connection terminals, the two connection terminals 5C and 5D disposed on the lower side of the page in <FIG> are dummy terminals. In the following description of this embodiment, the connection terminal 5A to which the one end of the antenna <NUM> is connected and the connection terminal 5B to which the other end of the antenna <NUM> is connected may be referred to as the input and output terminals 5A and 5B, respectively.

The insulating layer <NUM> is made of polyimide, epoxy resin, silicone resin, or the like, and is formed by spin coating, printing, or lamination. Further, the insulating layer <NUM> can be formed also by attaching a sheet or a film formed of a photosensitive resin such as photosensitive polyimide.

An annular antenna-forming area is set along substantially the entire outer periphery of the package of the IC chip <NUM>. The reason why such an area is set along substantially the entire outer periphery of the package is that a conductor line 3a connected to the connection terminal 5B is wound inside the connection terminal 5B, not between the connection terminal 5B and the outer peripheral edges of the package, so that the conductor line 3a does not overlap itself that is wound inwardly. Further, the antenna-forming area is set to have a specific width in a direction orthogonal to its circumferential direction.

The antenna <NUM> has a spiral-shaped conductor pattern formed within the antenna-forming area (inside the outer peripheral edges on the upper surface of the package (installation surface)). The conductor pattern is in a shape that is wound multiple times (<NUM> times in <FIG>) to be almost rectangular, and the portion where the winding of the conductor pattern starts extends straight from the connection terminal 5B toward an outer peripheral edge of the package and has a shape bending before the outer peripheral edge of the package.

In this embodiment, each round starting from the winding start of the conductor pattern may be referred to as a turn in the description. The innermost portion of the conductor pattern has a length less than one round but will be referred to as a turn in the same manner as the first round to the fourth round.

For the conductor pattern, various conductive materials can be used, where copper, silver, aluminum, and the like can be used, for example. Further, the conductor pattern is formed by various fabrication methods such as a thick-film method in which a conductor paste is applied and baked, sputtering, vapor deposition, vacuum plating, photolithography, and printing.

Each turn of the conductor pattern includes a plurality of sides of the conductor line 3a disposed corresponding to the outer peripheral edges of the upper surface of the package (installation surface). The plurality of sides of conductor line 3a are continuous with each other and are formed into a spiral so as to be turned within the antenna-forming area, with the input and output terminal 5A on one side serving as a starting point and the input and output terminal 5B on the other side serving as an endpoint.

The aspect ratio of the conductor line 3a is set within the range of <NUM> to <NUM>. In the antenna <NUM>, the larger the aspect ratio, the larger the cross-sectional area of the conductor line 3a becomes, thereby reducing resistance components of the wiring of the antenna <NUM>, which is preferable for the antenna <NUM>.

When the aspect ratio is over <NUM>, production of the antenna <NUM> becomes difficult. Therefore, the limit value of the aspect ratio in the antenna <NUM> is <NUM>.

When the aspect ratio in the antenna <NUM> is less than <NUM>, the number of turns of the conductor line 3a needs to be increased in order to ensure the resistance value, which results in an increase in the width of the conductor pattern. Accordingly, the number of turns of the conductor line 3a necessary for communication cannot be ensured within the antenna-forming area. Therefore, the minimum value of the aspect ratio is <NUM>.

As shown in <FIG>, the aspect ratio is a ratio (H/L) of a long-side length (longitudinal dimension) H with respect to a short-side length (lateral dimension) L in the longitudinal section of the conductor line 3a. In the following description of this embodiment, the normal direction to the installation surface of the antenna <NUM> may be referred to as the longitudinal direction, and the plane direction of the installation surface of the antenna <NUM> may be referred to as the lateral direction.

As shown in <FIG>, the opening area of an opening <NUM> of the conductor pattern is an area surrounded by the four sides of the conductor line 3a located on the innermost edges in the radial direction of the conductor line 3a, that is, surrounded by the conductor line 3a included in the fifth turn from the outside of the conductor pattern (which will be hereinafter referred to as first conductor line 3A) (see <FIG>).

The line width of the conductor line 3a, that is, the lateral dimension L of the conductor line 3a (see <FIG>) is constant or substantially constant across the full length of the conductor line 3a. The line width L of the conductor line 3a can be set to any value within the range of <NUM> pm to <NUM> pm and is set to <NUM> pm in this embodiment.

A spacing (so-called line spacing) S between the turns of the conductor line that are adjacent to each other in the radial direction can be set to any value within the range of <NUM> pm to <NUM> pm.

The conductor pattern is formed by the conductor line 3a wound into a spiral shape inside the outer peripheral edges on the upper surface of the IC chip <NUM>.

The conductor line 3a is wound into a spiral with its position shifted inwardly in every round. Therefore, the conductor line 3a is wound into a spiral at the spacing S from the portion of the conductor line 3a already provided on the upper surface of the IC chip <NUM>. In the conductor line 3a, the spacing S has a constant distance at each position in the winding direction.

Since one end of the conductor line 3a is connected to the input and output terminal 5B on the upper right side in <FIG>, the winding start portion of the conductor pattern extends from the input and output terminal 5B toward an outer peripheral edge of the package so that the conductor line 3a does not come into contact with itself that is thus connected to the input and output terminal 5B, and the portion following the winding start portion passes inside the input and output terminal 5B.

As described above, the IC chip <NUM> is <NUM> square (length <NUM> × width <NUM>), and distances Z1 and Z2 from the outermost edges of the IC chip <NUM> to the input and output terminal 5A (the input and output terminal on the upper left side in <FIG>) are <NUM> and <NUM>, respectively. The conductor line 3a in the first turn (one round from the winding start) to the fourth turn of the conductor pattern is disposed so as to pass between the input and output terminal 5A and the outermost edges of the IC chip <NUM>.

The conductor line 3a in the first to fourth turns of the conductor pattern passes also between the two dummy terminals 5C and 5D and the outermost edges of the IC chip <NUM>.

In this way, the conductor line 3a in the first to fourth turns of the conductor pattern is wound into a spiral and sequentially passes outside the connection terminals 5D, 5C, and 5A (between the connection terminals 5D, 5C, and 5A and the outer peripheral edges of the package) and inside the connection terminal 5B, which thereby allows the conductor line 3a to be wound into a spiral so as not to overlap itself in the inward and outward directions.

The conductor line 3a included in the fifth turn of the conductor pattern (that is, the first conductor line 3A) passes inside the dummy terminals 5C and 5D. The number of turns in the antenna is <NUM> but is set to any number from <NUM> to <NUM> corresponding to the resonance frequency (which is herein <NUM>).

When the line width L of the conductor line 3a is less than <NUM> pm, the conductor pattern cannot be produced, and when it exceeds <NUM>, the necessary number of turns cannot be ensured. Therefore, the line width L is set to a value within the range of <NUM> pm to <NUM>.

Similarly to the line width L of the conductor line 3a, when the spacing (so-called line spacing) S between the turns of the conductor line 3a is less than <NUM>, the conductor pattern cannot be produced, whereas when it exceeds <NUM>, the necessary number of turns cannot be ensured. Therefore, the distance is set to a value within the range of <NUM> to µ pm.

The distances Z1 and Z2 from the outermost edges of the IC chip <NUM> to the input and output terminal 5A are not limited to <NUM> and <NUM>, respectively, and can be set to any numerical values within the range of <NUM> to <NUM>, respectively. Further, although the case where the distance Z1 and the distance Z2 from the outermost edges of the IC chip <NUM> to the input and output terminal 5A are the same as each other is described herein, the distance Z1 and the distance Z2 may be different from each other.

The resonance frequency of the RFID tag configured as above is set to <NUM>. The resonance frequency f is determined by the following formula: <MAT> where L represents the equivalent inductance, and C represents the equivalent capacity of the IC chip generated between the input and output terminals 5A and 5B. The necessary equivalent inductance L of the coil from the aforementioned formula is determined by the following formula: <MAT> That is, in order to set the resonance frequency f to <NUM> (which may be any value of <NUM> to <NUM>) that is in the UHF band, either value L or C is determined so that the other value L or C is then determined accordingly.

C is a unique value determined for each IC chip <NUM>, and therefore it is necessary to appropriately set the value L based on the value C, and the value L is determined corresponding to the aspect ratio of the conductor line 3a, the line width L, and the spacing S between the turns of the conductor line 3a. These values are set within the aforementioned ranges.

The values of the aspect ratio of the conductor line 3a, the line width L, the spacing S between the turns of the conductor line 3a are set in the aforementioned ranges so that the conductor pattern <NUM> in which the conductor line 3A or 3a disposed close to the outer peripheral edges of the insulating layer is formed. As a result, it is possible not only to increase the radius of the antenna but also to increase the number of turns. Therefore, the radius of the antenna can be increased while the resistance to the current flowing through the conductor line is suppressed, and thus antenna efficiency (communication distance) can be improved by increasing the antenna gain (gain).

Further, the coil inductance L, a cross-sectional area S of the coil, and the number of turns N have a relation of L = AN<NUM>S, where A represents a constant. From the aforementioned formula, when the number of turns N increases and the cross-sectional area S of the coil increases, it is possible to increase the inductance L and reduce (lower) the resonance frequency.

Next, a method not claimed for producing an RFID tag by attaching the antenna <NUM> to the IC chip <NUM> will be described.

The upper surface of the IC chip <NUM> is coated with PI (polyimide) as an insulating layer. Then, the insulating layer is further coated with a seed layer for plating by sputtering. Further, a mold for depositing an antenna pattern is formed over the seed layer using a photoresist.

Subsequently, the process proceeds to a plating step, and the antenna pattern is deposited. Thereafter, the mold layer is removed, and then the exposed unnecessary seed layer is removed. Thereafter, a protective film to protect the antenna pattern is coated with PI (polyimide)to finish the production of the RFID tag.

Subsequently, according to the claimed invention a second embodiment will be described. As shown in <FIG> and <FIG>, the RFID tag <NUM> according to this embodiment includes the aforementioned antenna <NUM> provided on the upper surface of the IC chip <NUM> and a booster antenna <NUM> according to the claimed invention configured to operate at substantially the same frequency. The RFID tag <NUM> according to this embodiment has an advantage of being capable of enhancing the transmission/reception sensitivity and thereby increasing the information transmission distance, by including the booster antenna <NUM>. The antenna <NUM> mounted on the IC chip <NUM> has the same configuration as in <FIG>, <FIG>, <FIG>, and <FIG>, and therefore the relevant descriptions are omitted. In <FIG> and <FIG>, the antenna <NUM> is not shown.

The booster antenna <NUM> includes a conductor pattern (antenna) <NUM> in which a conductor line 9a is wound substantially <NUM> times (which may be multiple turns of <NUM> times or more up to <NUM> times) spirally in a ceramic insulating layer <NUM> stacked on the outer periphery of a ceramic rectangular base <NUM> (which may be made of other various synthetic resin materials) as an insulating layer (installation plane). A ceramic mount <NUM> having a recess 10A that is rectangular in plan view and is configured to mount the IC chip <NUM> is formed on the insulating layer <NUM>.

The antenna <NUM> is configured to resonate at the same frequency as that of the IC chip <NUM>. The antenna <NUM> performs communication by being electromagnetically coupled to the antenna <NUM> of the IC chip <NUM>. That is, the IC chip <NUM> performs communication with a reader/writer via the booster antenna <NUM>. Accordingly, although the size of the antenna <NUM> of the IC chip <NUM> is small, the communication distance can be increased by performing communication via the booster antenna <NUM> that is larger than the antenna <NUM> of the IC chip <NUM>. The reader/writer is a device capable of communicating with the IC chip <NUM>.

Since the antenna <NUM> of the IC chip <NUM> is constituted by an on-chip antenna in which the antenna <NUM> is integrally formed with the IC chip <NUM> itself, the need for contact points to connect the IC chip <NUM> and the antenna <NUM> to each other is eliminated.

Since the IC chip <NUM> and the booster antenna <NUM> are electromagnetically coupled to each other, there is an advantage of being environmentally resistant. For example, when a common RFID tag is used in an environment such as low temperature, high temperature, and vibration, the line may be disconnected in connected portions between the antenna and the IC (including adhesives), narrow-pattern portions of the antenna, or other portions due to vibration or deformation resulting from differences in thermal expansion among the antenna material, the base material, the adhesives, or the like. In contrast, when an RFID tag in which the IC chip <NUM> including the aforementioned on-chip antenna is combined with the booster antenna <NUM> electromagnetically coupled thereto is used, the IC chip <NUM> needs only to be installed around the center of the booster antenna <NUM> (the recess 10A in <FIG>), and therefore the RFID tag can be environmentally resistant, without line disconnection due to thermal expansion or vibration. Note that the IC chip <NUM> that has been installed around the center of the booster antenna <NUM> may also be molded with a resin having the same or almost the same coefficient of thermal expansion as ceramics.

As the conductor pattern <NUM>, various conductive materials can be used, where examples thereof can include copper, silver, and aluminum. The conductor pattern <NUM> is formed by various fabrication methods such as a thick-film method in which a conductor paste is applied and baked, sputtering, vapor deposition, vacuum plating, photolithography, and printing.

As shown in <FIG>, the opening area of an opening <NUM> of the conductor pattern <NUM> is an area surrounded by the four sides of a first conductor line 9A (see <FIG>) located on the innermost peripheral edges, in the conductor line 9a located in the radial direction.

The turns of the conductor line 9a that are adjacent to each other in the radial direction have substantially the same line width, that is, substantially the same short-side length (lateral dimension) L. Further, the number of turns in the antenna is <NUM>, but the number of turns is preferably any of <NUM> to <NUM>.

The RFID tag <NUM> shown in <FIG>, <FIG>, <FIG>, and <FIG> has a conductor pattern with <NUM> turns, but the RFID tag of may have a conductor pattern with <NUM> turns. The following will examine three types of RFID tags having different specifications (with the same number of the turns of <NUM>), and other four types of RFID tag models having specifications that are partially different as comparative examples, by making graphs of the amplitudes of the respective magnetic fields calculated by electromagnetic field simulations. <FIG> shows the magnetic field calculated by electromagnetic field simulations with contour lines. In <FIG>, a point located at a distance of <NUM> in the Z-axis direction from the center of the package of the RFID tag is referred to as Pobs, and the magnetic field at the point Pobs is calculated every <NUM> from <NUM> to <NUM>. These calculated values are plotted on a graph, with the horizontal axis representing the frequency (GHz) and the vertical axis representing the amplitude (A. ) of the magnetic field. Here, the amplitude of the magnetic field at <NUM> that is the operating frequency is important, and the larger the value of the amplitude, the more the communication distance is improved.

In <FIG>, the data of the RFID tag <NUM> are plotted with black dots, and the data of the RFID tag of model <NUM> as a comparative example are plotted with "+". In the RFID tag <NUM>, the antenna is disposed in the antenna-forming area between the outer peripheral edges of the insulating layer and the plurality of connection terminals, the aspect ratio is set to <NUM>, the line width of the turns of the conductor line 3a that are adjacent to each other in the radial direction is set to <NUM>, the spacing (so-called line spacing) S between the turns of the conductor line 3a from each other is set to <NUM> pm, and the number of turns is set to <NUM>. In contrast, in the RFID tag of model <NUM>, the antenna is disposed in the antenna-forming area between the outer peripheral edges of the insulating layer and the plurality of connection terminals, the aspect ratio is set to <NUM>, the line width of the turns of the conductor line 3a that are adjacent to each other in the radial direction is set to <NUM> (which is a value out of the range of the present invention), the spacing (so-called line spacing) S between the turns of the conductor line 3a from each other is set to <NUM> (which is a value out of the range of tag <NUM>), and the number of turns is set to <NUM>.

The reason why the number of turns in the conductor pattern is <NUM> is that, when a conductive material having a line width of <NUM> is wound once, as shown in <FIG>, a distance M between the conductor line 3a and the connection terminal 5B is <NUM>. In contrast, in the case where a conductive material in which the distance between the turns of the conductor is <NUM> and the line width is <NUM> is wound twice, the spacing between the turns of the conductor line 3a needs to be ensured also from the connection terminal 5B, and therefore a line width of <NUM> + distances between turns of conductor of <NUM>µ × <NUM> = <NUM> is needed, which exceeds <NUM> that is the distance M. Thus, such a conductive material cannot be wounded twice.

Therefore, the number of turns of the conductor pattern is limited up to <NUM>. The graph of <FIG> shows that, while the size of the magnetic field of the RFID tag <NUM> at <NUM> that is the operating frequency is a value over <NUM> (A. ), the size of the magnetic field of the RFID tag of model <NUM> at <NUM> that is the operating frequency is less than <NUM> (A. ), resulting that the communication distance of the RFID tag <NUM> can be increased as compared with that of the RFID tag of model <NUM>. In the RFID tag of model <NUM>, the line width of the conductor line 3a and the spacing between the turns of the conductor line 3a are out of the ranges of the present invention, and it is important that the line width falls within the range of <NUM> to <NUM>, and that the spacing between the turns of the conductor line 3a falls within the range of <NUM> to <NUM>, as in tag <NUM>.

In <FIG>, the data of the RFID tag <NUM> are plotted with black dots, the data of the RFID tag <NUM> having a different specification from the RFID tag <NUM> are plotted with black triangles, and the data of an RFID tag as a comparative example having a different specification from model <NUM> are plotted with outlined rhombuses.

In the RFID tag <NUM>, the antenna is disposed in the antenna-forming area between the outer peripheral edges of the insulating layer and the plurality of connection terminals, as described above, the aspect ratio is set to <NUM>, the line width of the turns of the conductor line 3a that are adjacent to each other in the radial direction is set to <NUM>, the spacing (so-called line spacing) S between the turns of the conductor line 3a from each other is set to <NUM>, and the number of turns in the conductor pattern is set to <NUM>.

Further, in the RFID tag <NUM>, the antenna is disposed in the antenna-forming area between the outer peripheral edges of the insulating layer and the plurality of connection terminals, in the same manner as in the RFID tag <NUM>, the aspect ratio is set to <NUM> (a value different from that in the tag <NUM>), the line width of the turns of the conductor line 3a that are adjacent to each other in the radial direction is set to <NUM> pm (the same value as that in the tag <NUM>), the spacing (so-called line spacing) S between the turns of the conductor line 3a from each other is set to <NUM> pm (a value different from that in the tag <NUM>), and the number of turns in the conductor pattern is set to <NUM>.

In contrast, in the RFID tag <NUM>, the antenna is disposed in the antenna-forming area between the outer peripheral edges of the insulating layer and the plurality of connection terminals, in the same manner as in the tag <NUM>, the aspect ratio is set to <NUM>, the line width of the turns of the conductor line 3a that are adjacent to each other in the radial direction is set to <NUM> pm (which is a value within the range of the present invention), the spacing (so-called line spacing) S between the turns of the conductor line 3a from each other is set to <NUM>, and the number of turns in the conductor pattern is set to <NUM>.

The graph of <FIG> shows that, while the size of the magnetic field of the RFID tags <NUM> and <NUM> at <NUM> that is the operating frequency is a value over <NUM> (A. ), the size of the magnetic field of the RFID tag of model <NUM> at <NUM> that is the operating frequency is nearly <NUM> (A. ), resulting that the communication distance of the RFID tags <NUM> and <NUM> can be increased as compared with that of the RFID tag of model <NUM>. In the RFID tag of model <NUM>, only the aspect ratio is out of the range of <NUM> to <NUM>, which is the range of the aspect ratio, and it is important that the aspect ratio is set within the range of <NUM> to <NUM>.

In <FIG>, the data of the RFID tag <NUM> are plotted with black dots, and the data of the RFID tag of model <NUM> as a comparative example are plotted with "×". In the RFID tag <NUM>, the antenna is disposed in the antenna-forming area between the outer peripheral edges of the insulating layer and the plurality of connection terminals, as described above, the aspect ratio is set to <NUM>, the line width of the turns of the conductor line 3a that are adjacent to each other in the radial direction is set to <NUM> pm, the spacing (so-called line spacing) S between the turns of the conductor line 3a from each other is set to <NUM> pm, and the number of turns in the conductor pattern is set to <NUM>.

In contrast, in the RFID tag of model <NUM>, the antenna is disposed in the antenna-forming area between the outer peripheral edges of the insulating layer and the plurality of connection terminals, the aspect ratio is set to <NUM>, the line width of the turns of the conductor line 3a that are adjacent to each other in the radial direction is set to <NUM> pm, the spacing (so-called line spacing) S between the turns of the conductor line 3a from each other is set to <NUM> (which is a value out of the range of the present invention), and the number of turns in the conductor pattern is set to <NUM> as in model <NUM>. The graph of <FIG> shows that, while the size of the magnetic field of the RFID tag <NUM> at <NUM> that is the operating frequency is a value over <NUM> (A. ), the size of the magnetic field of the RFID tag of model <NUM> at <NUM> that is the operating frequency is less than <NUM> (A. ), resulting that the communication distance of the RFID tag <NUM> can be increased as compared with that of the RFID tag of model <NUM>.

In the RFID tag of model <NUM>, all values of the aspect ratio, the line width of the conductor line 3a, and the spacing between the turns of the conductor line 3a are out of the ranges of the present invention, and it is important that the aspect ratio falls within the range of <NUM> to <NUM>, the line width of the conductor line 3a falls within the range of <NUM> to <NUM>, and the spacing between the turns of the conductor line falls within the range of <NUM> to <NUM>,.

In <FIG>, the data of the RFID tag <NUM> having a different specification from the specification of tag <NUM> and the specification of tag <NUM> are plotted with black squares, and the data of the RFID tag of model <NUM> as a comparative example are plotted with outlined downward triangles.

In the RFID tag <NUM>, the antenna is disposed in the antenna-forming area between the outer peripheral edges of the insulating layer and the plurality of connection terminals, as described above, the aspect ratio is set to <NUM> (a value different from the values of tags <NUM> and <NUM>), the line width of the turns of the conductor line 3a that are adjacent to each other in the radial direction is set to <NUM> pm (a value different from the values in the tags <NUM> and <NUM>), the spacing (so-called line spacing) S between the turns of the conductor line 3a from each other is set to <NUM> (a value different from the values of tags <NUM> and <NUM>), and the number of turns in the conductor pattern is set to <NUM>.

In contrast, in the RFID tag of model <NUM>, the antenna is disposed to be located in almost half of an antenna-forming area R between the outer peripheral edges of the insulating layer and the two input and output terminals 5A and 5B, as shown in <FIG>, the aspect ratio is set to <NUM>, the line width of the turns of the conductor line 3a that are adjacent to each other in the radial direction is set to <NUM>, the spacing (so-called line spacing) S between the turns of the conductor line 3a from each other is set to <NUM>, and the number of turns in the conductor pattern is set to <NUM>.

The graph of <FIG> shows that, while the size of the magnetic field of the RFID tag <NUM> at <NUM> that is the operating frequency is a value over <NUM> (A. ), the size of the magnetic field of the RFID tag of model <NUM> at <NUM> that is the operating frequency is nearly <NUM> (A. ), resulting that the communication distance of the RFID tag <NUM> can be increased as compared with that of the RFID tag of model <NUM>. This is considered to be because in the RFID tag of model <NUM>, almost half of the antenna <NUM> is disposed in an area shifted inwardly out of the antenna-forming area R formed on the outer periphery of the IC chip <NUM> and therefore the outer diameter dimension of the antenna <NUM> is reduced.

In the aforementioned embodiments, the antenna-forming area is formed over substantially the entire periphery of the insulating layer by winding the conductor line 3a inside the input and output terminal 5B so that the conductor line 3a wound inwardly does not overlap itself that is connected to the input and output terminal 5B, but the antenna-forming area may be formed over the entire periphery of the insulating layer by winding it so that the conductor line 3a wound inwardly overlaps itself that is connected to the input and output terminal 5B. In this case, in order to avoid the conductor line 3a overlapping itself (i.e., a portion of the conductor line 3a connected to the input and output terminal 5B and a portion of the conductor line 3a wound inwardly) from coming into contact with itself in the vertical direction, the insulating layer is formed so that one of the portions of the conductor line 3a is moved upward apart from the other portion and the conductor line 3a that has been moved upward is maintained at the position.

Further, in the aforementioned embodiments, the antenna is configured by disposing the conductor line 3a into a spiral in parallel, but the antenna that is wound multiple times may be configured by stacking two or more of single layers formed by disposing the conductor line 3a into a loop on the insulating layer.

Claim 1:
A booster antenna (<NUM>) for a spiral-shaped antenna (<NUM>) provided on an IC chip (<NUM>), wherein the booster antenna (<NUM>) is configured to operate at substantially the same frequency as an operating frequency of the spiral-shaped antenna (<NUM>), the booster antenna (<NUM>) comprising:
a ceramic rectangular base (<NUM>);
an insulating layer (<NUM>) made of ceramics and formed stacked on the ceramic rectangular base (<NUM>);
one conductor pattern (<NUM>) embedded in the ceramics of the insulating layer (<NUM>), the one conductor pattern (<NUM>) being constituted by a conductor line (9a) wound into a spiral to have an opening (<NUM>); and
a ceramic mount (<NUM>) for mounting the IC chip (<NUM>), wherein the ceramic mount (<NUM>) is stacked on the insulating layer (<NUM>) and wherein the ceramic mount (<NUM>) has a recess (10A) that is rectangular in plan view and is configured to mount the IC chip (<NUM>),
wherein the one conductor pattern (<NUM>) is configured to be electromagnetically coupled for resonance to the antenna (<NUM>) of the IC chip (<NUM>) in the state of being mounted on the mount (<NUM>) to thereby operate at substantially the same frequency as the operating frequency of the spiral-shaped antenna (<NUM>) of the IC chip (<NUM>).