Antenna device and radio frequency IC device

Abstract
An antenna device is arranged to transmit or receive a radio frequency communication signal to or from an external device such as a reader/writer, and is arranged such that an antenna resonance circuit including an antenna coil and a capacitor is connected to an additional resonance circuit including an inductor and a capacitor. A radio frequency IC device preferably includes the antenna device and a radio frequency IC. The antenna device is constructed such that a change in characteristics thereof caused by a change in the distance between a radio frequency IC device and a reader/writer is minimized, and the radio frequency IC device performs communication with high reliability.
Description
BACKGROUND OF THE INVENTION

1. Field of the Invention


The present invention relates to an antenna device used in a radio frequency IC device such as an RFID device that performs contactless communication by near-field transmission and a radio frequency IC device including the antenna device.


2. Description of the Related Art


Japanese Unexamined Patent Application Publication No. 2001-010264 discloses a contactless IC card used as an RFID device. FIG. 1 illustrates an equivalent circuit of the contactless IC card disclosed in Japanese Unexamined Patent Application Publication No. 2001-010264. This contactless IC card performs contactless communication with a reader/writer. A parallel resonance circuit is provided for a radio frequency IC chip 11. The parallel resonance circuit includes an inductor L provided by an antenna coil 13, a resistor R for the entire circuit, an adjusting resistor 14, a capacitor C for the entire circuit which has a capacitance based on the IC chip and a stray capacitance occurring in the circuit, and an adjusting capacitor having a capacitance Cad.


In order to obtain a good state of communication, the sharpness (Q) of the resonance circuit is controlled by controlling a resistance value Rad of the adjusting resistor 14 included in the resonance circuit and a resonance frequency is controlled by the capacitance Cad of an adjusting capacitor 15.


When such an IC card moves closer to a reader/writer so as to communicate with the reader/writer, however, antenna coils included in both of them are coupled and the inductance values of the antenna coils are changed. As a result, the resonance frequencies of the resonance circuits including the antenna coils are changed and gains are significantly changed.



FIGS. 2A-2C are diagrams illustrating the above-described situation. A resonance circuit 31 including an antenna coil Lr and a capacitor Cr is provided in a reader/writer 300. A resonance circuit including an antenna coil La and a capacitor Ca is formed in a radio frequency IC device 200, and is connected to a radio frequency IC 21.


An S11 characteristic (return loss) is represented by a characteristic curve Ra in FIG. 2C. The S11 characteristic is an S-parameter and is obtained when the antenna device is observed from the radio frequency IC 21 included in the radio frequency IC device 200. The return loss reaches its peak at a frequency foa when the radio frequency IC device 200 is located at an appropriate distance from the reader/writer 300.


On the other hand, as illustrated in FIG. 2B, if the radio frequency IC device 200 is excessively close to the reader/writer 300, the antenna coil La included in the radio frequency IC device 200 and the antenna coil Lr included in the reader/writer 300 are magnetically coupled and the inductances of both of them are increased. Accordingly, as illustrated in FIG. 2C using a characteristic curve Rb, the return loss reaches its peak at a frequency fob lower than the frequency foa.


Under the above-described condition in which the antenna included in the radio frequency IC device 200 and the antenna included in the reader/writer 300 are coupled by near-field transmission, as both of them get closer to each other, the resonance frequencies of both of the antennas are shifted in the direction of a lower frequency. If this antenna resonance frequency is lower than a frequency used by the radio frequency IC device 200 (that is, a communication frequency represented by a symbol fs in FIG. 2C), the antenna coil cannot function as an inductor and an antenna gain is significantly reduced. Consequently, communication cannot be performed.


In the conventional art, in order to prevent the resonance frequency from being lower than the communication frequency even if the resonance frequency is shifted in the direction of a lower frequency, it is required that the resonance frequency of the antenna device be set to a frequency that is 10 to 20 percent higher than the communication frequency in advance. Furthermore, in order to make communication possible even under the condition in which the resonance frequency is higher than the communication frequency, it is required that the value Q of a resonance circuit including an antenna coil be set to a low value by disposing a resistor in the resonance circuit as illustrated in FIG. 1.


However, under the conditions allowing the radio frequency IC device 200 to communicate with the reader/writer 300 even if they are excessively close to each other, a resonance frequency of an antenna of the radio frequency IC device 200, which is obtained when the distance therebetween is normal, is shifted to a direction of a frequency higher than the communication frequency. Accordingly, if the distance between the radio frequency IC device 200 and the reader/writer 300 is larger than the normal distance, antenna gains are significantly reduced. Consequently, a sufficient communication distance cannot be obtained.


Furthermore, when the value Q of the resonance frequency including an antenna coil is set to a lower value, a relatively stable gain can be obtained with the broad characteristics of the resonance circuit even if the resonance frequency is shifted. On the other hand, however, since the value Q is set to a lower value, a gain is lowered regardless of the distance between the radio frequency IC device and the reader/writer.


SUMMARY OF THE INVENTION

Preferred embodiments of the present invention provide an antenna device in which the characteristics thereof are not significantly changed despite the influence of changes in the distance between a radio frequency IC device and a reader/writer and also provide a radio frequency IC device capable of achieving communication with high reliability.


An antenna device according to a preferred embodiment of the present invention includes an antenna coil arranged to transmit or receive a radio frequency communication signal to or from an external device, and an additional resonance circuit that is connected to the antenna resonance circuit, including at least one inductor, and that has a resonance frequency characteristic different from that of the antenna resonance circuit.


In the above-described configuration, for example, the resonance frequency of the additional resonance circuit is preferably set to a frequency lower than the resonance frequency of the antenna resonance circuit. As a result, the decrease in the resonance frequency of the antenna resonance circuit can be minimized and prevented by the resonance frequency of the additional resonance circuit even if a radio frequency IC device moves closer to the external device such as a reader/writer, antenna coils included both of them are magnetically coupled, and inductance values are thereby increased. Consequently, the amount of change in the resonance frequency of the antenna resonance circuit is reduced and a high gain can be stably obtained.


Conversely, the resonance frequency of the additional resonance circuit is preferably set to a frequency higher than the resonance frequency of the antenna resonance circuit, and is preferably set such that the resonance frequency of the antenna resonance circuit is higher than a communication frequency even in the condition in which the radio frequency IC device is excessively close to the reader/writer (the external device). As a result, even if the radio frequency IC device moves away from the reader/writer, an increase in the resonance frequency of the antenna resonance circuit (movement of it to the resonance frequency of the additional resonance circuit) can be prevented and minimized. Consequently, the amount of the change in the resonance frequency of the antenna resonance circuit is reduced, and the condition in which the resonance frequency of the antenna resonance circuit is near the communication frequency can be maintained over a wide communication range.


A magnetic field coupling between the antenna coil and the inductor included in the additional resonance circuit may be achieved. As a result, even if the resonance frequency of the antenna resonance circuit moves closer to the resonance circuit of the additional resonance circuit in accordance with the increase in an inductance value, it cannot easily jump over the resonance frequency of the additional resonance circuit. This can enhance the stability of the resonance frequency of the antenna resonance circuit.


The additional resonance circuit is, for example, a parallel resonance circuit. As a result, the inductance value of the additional resonance circuit can be a small value. This leads to the miniaturization of the additional resonance circuit.


For example, the antenna resonance circuit is connected in series to the additional resonance circuit. As a result, the magnetic field coupling between the antenna coil included in the antenna resonance circuit and the inductor included in the additional resonance circuit can be more easily achieved.


In particular, the resonance frequency of the antenna resonance circuit is preferably set to a frequency higher than a frequency used by the radio frequency IC device (a communication frequency), and the resonance frequency of the additional resonance circuit is set to a frequency lower than the communication frequency. As a result, as the radio frequency IC device including the antenna device moves closer to the external device such as a reader/writer, the resonance frequency of the antenna resonance circuit moves closer to the communication frequency. A higher gain can be therefore obtained.


For example, inductors included in the additional resonance circuits may individually include two adjacent lines of different lengths.


In this configuration, the range of resonance frequencies of the additional resonance circuits can be broadened. The effects of minimizing and preventing the change in the resonance frequency of the antenna resonance circuit can be enhanced by using the additional resonance circuits.


The inductor included in the additional resonance circuit may be magnetically shielded. As a result, even if the radio frequency IC device including the antenna device moves closer to the external device such as a reader/writer, the magnetic field coupling between the antenna device and the antenna coil included in the external device can be prevented. Accordingly, the inductance value of the inductor included in the additional resonance circuit is not changed. This can stabilize the resonance frequency of the additional resonance circuit. The resonance frequency of the antenna resonance circuit can be further stabilized.


The additional resonance circuit may be provided in a multilayer substrate including a magnetic substance. As a result, a thin device can be obtained, and the upsizing of the device due to the installation of the additional resonance circuit can be prevented. Furthermore, magnetic shielding can be simultaneously performed.


An output inductor may be connected in series to an input portion for receiving a signal transmitted from a radio frequency IC and may be provided in the multilayer substrate. As a result, an impedance matching circuit including the radio frequency IC and the antenna device is simultaneously provided in the multilayer substrate. The device can therefore be further miniaturized.


The capacitance component of the additional resonance circuit may be a chip capacitor and may be disposed on a surface of the multilayer substrate or in the multilayer substrate. As a result, the multilayer substrate can be further miniaturized, and an area required for the multilayer substrate can be reduced in the radio frequency IC device.


A radio frequency IC device according to a preferred embodiment of the present invention includes an antenna device including a multilayer substrate and a radio frequency IC chip disposed on a surface of the multilayer substrate or in the multilayer substrate. As a result, a module (an RFID module) including a radio frequency IC chip can be provided. The installation of the antenna device and the radio frequency IC in the radio frequency IC device can be easily performed.


According to a preferred embodiment of the present invention, a decrease in the resonance frequency of the antenna resonance circuit can be minimized and prevented by the resonance frequency of the additional resonance circuit even if the radio frequency IC device moves closer to the external device such as a reader/writer, antenna coils included both of them are magnetically coupled, and inductance values are therefore increased. Consequently, the amount of change in the resonance frequency of the antenna resonance circuit is reduced and a high gain can be stably obtained.


Conversely, even if the radio frequency IC device moves away from the external device, the change in the resonance frequency of the antenna resonance circuit can be minimized and prevented. Consequently, the condition in which the resonance frequency of the antenna resonance circuit is near the communication frequency can be maintained over a wide communication range.


Other features, elements, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the present invention with reference to the attached drawings.





BRIEF DESCRIPTION OF THE DRAWINGS


FIG. 1 is a circuit diagram of a contactless IC card described in Japanese Unexamined Patent Application Publication No. 2001-010264.



FIGS. 2A-2C are diagrams describing a problem of a radio frequency IC device in the related art.



FIG. 3 is a circuit diagram illustrating configurations of a radio frequency IC device according to a first preferred embodiment and an antenna device according to the first preferred embodiment of the present invention.



FIGS. 4A and 4B are diagrams illustrating S11 characteristics (return losses) obtained when the distance between a radio frequency IC device according to the first preferred embodiment and a reader/writer is changed.



FIGS. 5A and 5B are diagrams illustrating S11 characteristics (return losses) obtained when the distance between a radio frequency IC device, which is a comparative example of the first preferred embodiment, and a reader/writer is changed.



FIGS. 6A-6C are diagrams illustrating the relationship between the resonance frequency of an additional resonance circuit and the decrease in the resonance frequency of an antenna resonance circuit which is caused by the magnetic field coupling between the antenna resonance circuit and the antenna of a reader/writer.



FIGS. 7A and 7B are diagrams illustrating impedance loci of an antenna device which are obtained when a frequency is changed in different conditions of the distance between a radio frequency IC device according to the first preferred embodiment and a reader/writer.



FIGS. 8A and 8B are diagrams illustrating impedance loci of an antenna device which are obtained when a frequency is changed in different conditions of the distance between a radio frequency IC device, which is a comparative example of the first preferred embodiment, and a reader/writer.



FIGS. 9A and 9B are diagrams illustrating S11 characteristics of an antenna device included in a radio frequency IC device according to a second preferred embodiment which are obtained when the distance between the radio frequency IC device and a reader/writer is changed.



FIGS. 10A-10D are diagrams illustrating a configuration of a radio frequency IC device according to a third preferred embodiment of the present invention.



FIG. 11 is a diagram illustrating an exemplary unbalanced antenna device according to a third preferred embodiment and an exemplary radio frequency IC device according to the third preferred embodiment of the present invention.



FIG. 12 is a circuit diagram of an antenna device according to a fourth preferred embodiment and a radio frequency IC device including the antenna device.



FIG. 13 is a diagram illustrating an S11 characteristic of an antenna device according to the fourth preferred embodiment of the present invention.



FIGS. 14A and 14B are diagrams illustrating a configuration of a radio frequency IC device according to a fifth preferred embodiment of the present invention.



FIG. 15 is a circuit diagram illustrating configurations of a radio frequency IC device according to a sixth preferred embodiment and an antenna device included in the radio frequency IC device.



FIGS. 16A and 16B are diagrams illustrating a configuration of a module according to a sixth preferred embodiment and the entire configuration of a radio frequency IC device.





DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Preferred Embodiment



FIG. 3 is a circuit diagram of a radio frequency IC device 201 according to the first preferred embodiment. Referring to FIG. 3, an antenna resonance circuit AR including an antenna coil La and a capacitor Ca and an additional resonance circuit LC1 including a parallel circuit of an inductor L1 and a capacitor C1 are formed. The additional resonance circuit LC1 is connected in series to the antenna resonance circuit AR and is connected to a radio frequency IC 21.


An antenna device 101 preferably includes the antenna resonance circuit AR and the additional resonance circuit LC1. The radio frequency IC device 201 preferably includes the antenna device 101 and the radio frequency IC 21.


The radio frequency IC device 201 is, for example, an RFID card. The antenna coil La has a spiral conductor pattern inside the card. The conductor pattern has a plurality of turns and is located along the periphery of the card. The capacitor Ca includes opposite electrodes between which a dielectric layer is sandwiched. The inductor L1 and the capacitor C1 are provided in a ferrite multilayer substrate. This ferrite multilayer substrate and the radio frequency IC 21 are sealed in the card, whereby a single RFID card is provided.



FIGS. 4A and 4B are diagrams illustrating the antenna characteristics of the antenna device 101 illustrated in FIG. 3. FIGS. 5A and 5B are diagrams illustrating the antenna characteristics of an antenna device that does not include the additional resonance circuit LC1. In the drawings, the S11 characteristic (return loss), which is an S-parameter, is illustrated.


Each of FIGS. 4A and 5A illustrate a characteristic obtained in a normal condition in which the radio frequency IC device 201 is located at an appropriate distance from a reader/writer, and Each of FIGS. 4B and 5B illustrate a characteristic obtained in a condition in which both of them are excessively close to each other.


If the additional resonance circuit LC1 illustrated in FIG. 3 is not included, as illustrated in FIG. 5A, a resonance frequency foa of the antenna resonance circuit AR is approximately 15.0 MHz in the normal condition in which the radio frequency IC device is located at an appropriate distance from the reader/writer. That is, the resonance frequency foa is set to a frequency higher than a communication frequency fs (for example, 13.56 MHz). Since the resonance frequency foa of the antenna resonance circuit AR is higher than the communication frequency fs as described previously, the magnetic field coupling between the antenna device of the radio frequency IC device and the antenna of the reader/writer can be achieved and communication between them can be performed.


However, in a condition where the antenna of the radio frequency IC device and the antenna of the reader/writer are excessively close to each other, as illustrated in FIG. 5B, a resonance frequency fob of the antenna resonance circuit AR is lower than the communication frequency fs. At that time, the antenna device of the radio frequency IC device and the antenna of the reader/writer are capacitively coupled to each other. Since the magnetic field coupling between them cannot be achieved using an antenna coil included in the antenna resonance circuit (a current does not flow through the antenna coil), communication between them cannot be performed.


On the other hand, if the antenna device 101 according to the first preferred embodiment is used, a resonance frequency fla of the additional resonance circuit LC1 is approximately 12.9 MHz and the resonance frequency foa of the antenna resonance circuit AR is approximately 15.2 MHz in the normal condition as illustrated in FIG. 4A. Since the resonance frequency foa is higher than the communication frequency of 13.56 MHz and is relatively near to the communication frequency, the radio frequency IC device 201 can communicate with the reader/writer.


In the condition in which the radio frequency IC device 201 is excessively close to the reader/writer, as illustrated in FIG. 4B, the resonance frequency fob of the antenna resonance circuit is 13.56 MHz that is almost the same as the communication frequency fs. Accordingly, the strong magnetic field coupling between the antenna device 101 of the radio frequency IC device 201 and the antenna of the reader/writer is achieved, and therefore they can normally communicate with each other.


As illustrated in FIG. 4B, a resonance frequency flb of the additional resonance circuit LC1 is shifted in a direction of a lower frequency in accordance with the decrease in the resonance frequency fob of the antenna resonance circuit AR.


Next, the relationship between the resonance frequency of the additional resonance circuit LC1 and the decrease in the resonance frequency of the antenna resonance circuit AR, which is caused by magnetic field coupling between the antenna resonance circuit AR and the antenna of the reader/writer, will be described with reference to FIGS. 6A-6C. In a condition in which the radio frequency IC device 201 can communicate with the reader/writer and is furthest from the reader/writer, as illustrated in FIG. 6A, the resonance frequency foa of the antenna resonance circuit AR is higher than the resonance frequency fla of the additional resonance circuit LC1 and is relatively far from the resonance frequency fla.


As the radio frequency IC device 201 moves closer to the reader/writer, as illustrated in FIG. 6B, the resonance frequency fob of the antenna resonance circuit is lowered from the resonance frequency foa of the antenna resonance circuit AR. In accordance with this, the resonance frequency flb of the additional resonance circuit LC1 is slightly shifted in a direction of a frequency lower than the resonance frequency foa. However, the amount of this shift is smaller than that of the resonance frequency of the antenna resonance circuit AR (foa−fob).


Thus, the additional resonance circuit LC1 prevents the resonance frequency of the antenna resonance circuit AR from becoming lower than the resonance frequency flb thereof.


If a stronger magnetic field coupling between the antenna coil La included in the radio frequency IC device 201 and the antenna coil included in the reader/writer is achieved and the resonance frequency of the antenna resonance circuit is further lowered, as illustrated in FIG. 6C using a symbol foc, the resonance frequency of the antenna resonance circuit jumps over a resonance frequency flc of the additional resonance circuit LC1 in a direction of a frequency lower than the resonance frequency flc. That is, the additional resonance circuit LC1 prevents the resonance frequency of the antenna resonance circuit from jumping over the resonance frequency thereof. Accordingly, the resonance frequency of the additional resonance circuit LC1 is set such that the resonance frequency of the antenna resonance circuit AR does not jump over the resonance frequency of the additional resonance circuit LC1. That is, the resonance frequency of the additional resonance circuit LC1 is determined such that the state illustrated in FIG. 6C can be prevented even in the condition in which the radio frequency IC device is nearest to the reader/writer.



FIGS. 7A, 7B, 8A, and 8B are Smith charts illustrating changes in impedance with respect to changes in frequency which are obtained in the antenna device 101 used in a radio frequency IC device according to the first preferred embodiment illustrated in FIG. 1 and in an antenna device that does not include the additional resonance circuit LC1.



FIGS. 7A and 7B illustrate a characteristic of the antenna device 101 illustrated in FIG. 3. FIGS. 8A and 8B illustrate a characteristic of an antenna device that does not include the additional resonance circuit LC1. FIGS. 7A and 8A represent a characteristic in a normal condition in which the radio frequency IC device 201 is located at an appropriate distance from a reader/writer, and FIGS. 7B and 8B represent a characteristic in a condition in which both of them are excessively close to each other. A frequency is changed in a range of about 11.06 to about 16.06 MHz, for example. Furthermore, an impedance at a communication frequency of about 13.56 MHz is represented using a marker [1].


If the additional resonance circuit LC1 is not included, as illustrated in FIGS. 8A and 8B, the impedance at the communication frequency of about 13.56 MHz (the position of the marker [1] in the drawing) exists in the lower half of the Smith chart in the condition in which the radio frequency IC device is excessively close to the reader/writer. That is, the antennas of both of them are capacitively coupled, and a current does not flow through the antenna coil La included in the antenna device. Consequently, communication cannot be performed.


On the other hand, in the antenna device 101 according to the first preferred embodiment, the impedance at the communication frequency of about 13.56 MHz (the position of the marker [1] in the drawings) exists in the upper half of each of the Smith charts regardless of whether the radio frequency IC device is located at an appropriate distance from the reader/writer or is excessively close to the reader/writer. That is, it can be understood that the impedance represents inductivity and the magnetic field coupling between the antennas of both of them is achieved.


Thus, the radio frequency IC device 201 can stably communicate with the reader/writer even if the distance between them is changed.


The magnetic field coupling between the antenna coil La and the inductor L1 included in the additional resonance circuit LC1, which are illustrated in FIG. 3, may be achieved. As a result, the effect of reducing the amount of shift of the resonance frequency of the antenna resonance circuit AR in a direction of the resonance frequency of the additional resonance circuit LC1 is enhanced. This can further stabilize the resonance frequency of the antenna resonance circuit AR.


Second Preferred Embodiment


In the first preferred embodiment, the resonance frequency of the antenna resonance circuit AR is preferably set to a frequency higher than the communication frequency fs, and the resonance frequency of the additional resonance circuit LC1 is preferably set to a frequency lower than the resonance frequency of the antenna resonance circuit AR. In the second preferred embodiment, an example in which the resonance frequency of the additional resonance circuit LC1 is preferably set to a frequency higher than the resonance frequency of the antenna resonance circuit AR will be described.



FIGS. 9A and 9B illustrate an S11 characteristic of an antenna device included in a radio frequency IC device which is changed in accordance with the change in the distance between the radio frequency IC device and a reader/writer. FIG. 9A illustrates a characteristic obtained in the condition in which the radio frequency IC device is excessively close to the reader/writer. In this condition, the resonance frequency foa of the antenna resonance circuit is set to a frequency higher than the communication frequency fs.


In the condition in which the radio frequency IC device is located at an appropriate distance from the reader/writer, the magnetic field coupling between both of the antennas of the radio frequency IC device and the reader/writer is weak. Accordingly, as illustrated in FIG. 9B, the inductance of the antenna coil included in the antenna resonance circuit becomes small and the resonance frequency fob is increased. However, the resonance frequency fob of the antenna resonance circuit does not become significantly higher than the communication frequency fs, since the resonance frequency flb of the additional resonance circuit is used for suppression of the increase in the resonance frequency fob of the antenna resonance circuit.


Thus, the radio frequency IC device can stably communicate with the reader/writer even if the distance between them is changed.


Third Preferred Embodiment


Next, some examples of the configuration of the additional resonance circuit will be described as the third preferred embodiment with reference to FIGS. 10A, 10B, 10C, 10D, and 11.


In an example illustrated in FIG. 10A, the additional resonance circuit LC1 that includes a series circuit of the inductor L1 and the capacitor C1 is connected in parallel to the antenna resonance circuit AR, whereby an antenna device 102 is provided.


In an example illustrated in FIG. 10B, the additional resonance circuit LC1 that includes a series circuit of the inductor L1 and the capacitor C1 is connected in series to the antenna resonance circuit AR, whereby an antenna device 103 is provided.


In an example illustrated in FIG. 10C, the additional resonance circuit LC1 that includes a parallel circuit of the inductor L1 and the capacitor C1 is connected in parallel to the antenna resonance circuit AR via capacitors C3 and C4, whereby an antenna device 104 is provided. In the above examples, a plurality of additional resonance circuits LC1 may be included.


In an example illustrated in FIG. 10D, the antenna resonance circuit AR preferably includes a parallel circuit of the antenna coil La and the capacitor Ca, the additional resonance circuit LC1 preferably includes a parallel circuit of the inductor L1 and the capacitor C1, and the additional resonance circuit LC1 is connected to the radio frequency IC 21. The antenna coil La and the inductor L1 are disposed such that the antenna coil La is magnetically coupled to the inductor L1, whereby an antenna device 105 is provided. Thus, the antenna resonance circuit AR and the additional resonance circuit LC1 may be inductively coupled.


In the configurations illustrated in FIGS. 10A to 10C, the magnetic field coupling between the antenna coil La and the inductor L1 included in the additional resonance circuit LC1 may also be achieved. As a result, as described previously, the effect of reducing the amount of shift of the resonance frequency of the antenna resonance circuit AR in a direction of the resonance frequency of the additional resonance circuit LC1 is enhanced. This can further stabilize the resonance frequency of the antenna resonance circuit AR.


In the above-described examples of the third preferred embodiment, the radio frequency IC 21 is a balanced IC arranged to receive or output a signal, and the antenna device is therefore also a balanced antenna device. In an example of the third preferred embodiment illustrated in FIG. 11, however, the radio frequency IC 21 is an unbalanced IC arranged to receive or output a signal, and an antenna device 106 is also an unbalanced antenna device. In this example, the additional resonance circuit LC1 in which the inductor L1 and the capacitor C1 are connected in parallel is connected in series to the antenna resonance circuit AR. Like the case of the balanced antenna device, there are other configurations of the additional resonance circuit LC1 and other configurations of a connection between the additional resonance circuit LC1 and the antenna resonance circuit AR. For example, one of the lines illustrated in FIG. 10A may be connected to the ground.


Fourth Preferred Embodiment


The fourth preferred embodiment is an example in which the stability of the resonance frequency of the antenna resonance circuit is further enhanced using two additional resonance circuits.



FIG. 12 is a circuit diagram of a radio frequency IC device 207 including an antenna device 107 according to the fourth preferred embodiment. In this example, the first additional resonance circuit LC1 including the parallel circuit of the inductor L1 and the capacitor C1 and a second additional resonance circuit LC2 including the parallel circuit of an inductor L2 and a capacitor C2 are connected in series to the antenna resonance circuit AR, whereby the antenna device 107 is provided.



FIG. 13 is a diagram illustrating an S11 characteristic of the antenna device 107 illustrated in FIG. 12. A resonance frequency f1 of the first additional resonance circuit LC1 is set to a frequency lower than a resonance frequency fo of the antenna resonance circuit AR. A resonance frequency f2 of the second additional resonance circuit LC2 is set to a frequency higher than the resonance frequency fo of the antenna resonance circuit. The resonance frequency fo of the antenna resonance circuit AR is set to a frequency higher than the communication frequency fs.


As the radio frequency IC device according to the fourth preferred embodiment moves closer to a reader/writer, the resonance frequency fo of the antenna resonance circuit is lowered. However, the additional resonance circuit LC1 reduces the amount of the shift of the resonance frequency fo of the antenna resonance circuit in a direction of a lower frequency. The resonance frequencies fo and f1 are determined such that the resonance frequency fo does not jump over the communication frequency fs even in the condition in which the radio frequency IC device is excessively close to the reader/writer. If the radio frequency IC device moves apart from the reader/writer, the resonance frequency fo of the antenna resonance circuit is shifted in a direction of a higher frequency. However, the shift amount is reduced by the second additional resonance circuit LC2. Accordingly, the resonance frequency fo of the antenna resonance circuit AR can always be in the vicinity of the communication frequency fs regardless of the distance between the radio frequency IC device and the reader/writer. Thus, by disposing at least two additional resonance frequency circuits, the resonance frequency of the antenna resonance circuit can be stabilized in both of the direction of a lower frequency and the direction of a higher frequency.


As another example, both of the resonance frequencies of the two additional resonance circuits may exist on the side of a frequency lower or higher than the resonance frequency of the antenna resonance circuit. In this case, as compared with the case in which only a single additional resonance circuit is disposed, the stability of the resonance frequency of the antenna resonance circuit is further enhanced.


In each of the circuit configurations illustrated in FIGS. 10A-10D, two or more additional resonance circuits may be similarly disposed.


Fifth Preferred Embodiment



FIGS. 14A and 14B are diagrams illustrating the configuration of the radio frequency IC device 207 according to the fifth preferred embodiment. This example is an RFID card, and FIG. 14A illustrates the internal configuration of the card. FIG. 14B is an enlarged view of a module 22 included in the card.


The antenna coil La has a spiral conductor pattern inside the card. The conductor pattern has a plurality of turns and is located along the periphery of the card. The capacitor Ca includes opposite electrodes between which a dielectric layer is sandwiched.


The module 22 includes two adjacent lines SL1 and SL2 having different lengths and the radio frequency IC (chip) 21.


A capacitance is generated between the two lines SL1 and SL2 included in the module 22. Two additional resonance circuits preferably include the generated capacitance and the inductances of the lines SL1 and SL2. Accordingly, if the radio frequency IC device 207 is equivalently represented by a lumped-constant circuit, the lumped-constant circuit is the same as the circuit according to the fourth preferred embodiment illustrated in FIG. 12. Since the lines SL1 and SL2 have different lengths, different resonance frequencies of the two additional resonance circuits can be obtained.


Sixth Preferred Embodiment



FIG. 15 is a circuit diagram illustrating the configuration of a radio frequency IC device 208 according to the sixth preferred embodiment which includes an antenna device 108. In FIG. 15, a circuit arranged to output a signal from the radio frequency IC 21 is also illustrated. An input portion for receiving a signal output from the radio frequency IC 21 is connected in series to output inductors L3 and L4. A matching circuit is defined by the output inductors L3 and L4 and capacitors C5, C6, and C7. More specifically, switching is performed in the radio frequency IC 21 by short-circuiting or opening one end of the output inductor L3 and one end of the output inductor L4 so as to change an impedance (return loss) which is obtained when the radio frequency IC device is observed from the antenna device included in the reader/writer. The reader/writer detects the change in the impedance, thereby receiving the signal transmitted from the radio frequency IC device.


The antenna device 108 has the antenna coil La, the capacitor Ca, a fist additional resonance circuit including the inductor L2 and the capacitor C2, and a second additional resonance circuit including the inductor L2 and the capacitor C2. Components other than the radio frequency IC 21 and the antenna coil La are included in a module 23.



FIGS. 16A and 16B are diagrams illustrating the configuration of the module 23 and the entire configuration of the radio frequency IC device 208. The module 23 preferably includes a multilayer ferrite substrate. On an upper layer 23a of the multilayer substrate, the inductor L1 included in the first additional resonance circuit and the inductor L2 included in the second additional resonance circuit are provided. On a lower layer 23b of the multilayer substrate, the output inductors L3 and L4 are provided. Between the upper layer 23a and the lower layer 23b, a non-magnetic ceramic layer having a relative magnetic permeability μr of approximately one is sandwiched so as to prevent magnetic coupling.


In the upper layer 23a of the multilayer substrate, the inductor L1 and the inductor L2 are magnetically coupled. In the lower layer 23b of the multilayer substrate, the two output inductors L3 and L4 are magnetically coupled.


Thus, by achieving the magnetic field coupling between the inductors L1 and L2, the intervals of the resonance frequencies of the two additional resonance circuits can be fixed.


Chip capacitors corresponding to the capacitors C1, C2, C5, C6, and C7 illustrated in FIG. 15 are provided on the surface of the module 23 or in the module 23. The radio frequency IC 21 is also provided either on the surface of the multilayer substrate or in the multilayer substrate. In the case of the radio frequency IC 21, a cavity may be provided in the multilayer substrate and the radio frequency IC 21 may be disposed in the cavity.


Consequently, almost all of the required components can be included in a single module. Accordingly, for example, at the time of making an RFID card, the RFID card can be made only by forming the antenna coil La on the card in the form of a conductive pattern and installing the module 23 in the card.


In the case of a mobile telephone having an RFID function, the antenna coil La may be provided using a coil electrode disposed in the mobile telephone.


While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.

Claims
  • 1. An antenna device included in a radio frequency IC device that is arranged to perform radio frequency communication with an external device, the antenna device comprising: an antenna element arranged to transmit or receive a radio frequency communication signal to or from the external device; andan additional resonance circuit connected to the antenna element, including at least one inductor, and having a resonance frequency different from a resonance frequency of the antenna element; whereinthe resonance frequency of the additional resonance circuit is higher than the resonance frequency of the antenna element, and the resonance frequency of the antenna element is higher than a communication frequency used by the radio frequency IC device.
  • 2. The antenna device according to claim 1, wherein the antenna element and the inductor included in the additional resonance circuit are arranged to be magnetically coupled.
  • 3. The antenna device according to claim 1, wherein the additional resonance circuit is a parallel resonance circuit.
  • 4. The antenna device according to claim 1, wherein the antenna element is connected in series to the additional resonance circuit.
  • 5. The antenna device according to claim 1, wherein the inductor included in the additional resonance circuit is magnetically shielded.
  • 6. The antenna device according to claim 5, wherein the additional resonance circuit is provided in a multilayer substrate including a magnetic substance.
  • 7. The antenna device according to claim 6, further comprising an output inductor that is connected in series to an input portion that is arranged to receive a signal transmitted from a radio frequency IC and is provided in the multilayer substrate.
  • 8. The antenna device according to claim 6, wherein the additional resonance circuit includes a chip capacitor disposed either on a surface of the multilayer substrate, or in the multilayer substrate.
  • 9. A radio frequency IC device comprising: the antenna device according to claim 6; anda radio frequency IC disposed either on a surface of the multilayer substrate of the antenna device, or in the multilayer substrate of the antenna device.
Priority Claims (1)
Number Date Country Kind
2007-334413 Dec 2007 JP national
US Referenced Citations (116)
Number Name Date Kind
3364564 Kurtz et al. Jan 1968 A
4794397 Ohe et al. Dec 1988 A
5232765 Yano et al. Aug 1993 A
5253969 Richert Oct 1993 A
5337063 Takahira Aug 1994 A
5374937 Tsunekawa et al. Dec 1994 A
5399060 Richert Mar 1995 A
5491483 D'Hont Feb 1996 A
5528222 Moskowitz et al. Jun 1996 A
5757074 Matloubian et al. May 1998 A
5854480 Noto Dec 1998 A
5903239 Takahashi et al. May 1999 A
5936150 Kobrin et al. Aug 1999 A
5955723 Reiner Sep 1999 A
5995006 Walsh Nov 1999 A
6104311 Lastinger Aug 2000 A
6107920 Eberhardt et al. Aug 2000 A
6172608 Cole Jan 2001 B1
6181287 Beigel Jan 2001 B1
6190942 Wilm et al. Feb 2001 B1
6249258 Bloch et al. Jun 2001 B1
6259369 Monico Jul 2001 B1
6271803 Watanabe et al. Aug 2001 B1
6335686 Goff et al. Jan 2002 B1
6362784 Kane et al. Mar 2002 B1
6367143 Sugimura Apr 2002 B1
6378774 Emori et al. Apr 2002 B1
6406990 Kawai Jun 2002 B1
6448874 Shiino et al. Sep 2002 B1
6462716 Kushihi Oct 2002 B1
6542050 Arai et al. Apr 2003 B1
6600459 Yokoshima et al. Jul 2003 B2
6634564 Kuramochi Oct 2003 B2
6664645 Kawai Dec 2003 B2
6763254 Nishikawa Jul 2004 B2
6812707 Yonezawa et al. Nov 2004 B2
6828881 Mizutani et al. Dec 2004 B2
6837438 Takasugi et al. Jan 2005 B1
6861731 Buijsman et al. Mar 2005 B2
6927738 Senba et al. Aug 2005 B2
6963729 Uozumi Nov 2005 B2
7088249 Senba et al. Aug 2006 B2
7088307 Imaizumi Aug 2006 B2
7112952 Arai et al. Sep 2006 B2
7119693 Devilbiss Oct 2006 B1
7129834 Naruse et al. Oct 2006 B2
7248221 Kai et al. Jul 2007 B2
7250910 Yoshikawa et al. Jul 2007 B2
7276929 Arai et al. Oct 2007 B2
7317396 Ujino Jan 2008 B2
7405664 Sakama et al. Jul 2008 B2
20020011967 Goff et al. Jan 2002 A1
20020015002 Yasukawa et al. Feb 2002 A1
20020044092 Kushihi Apr 2002 A1
20020067316 Yokoshima et al. Jun 2002 A1
20020093457 Hamada et al. Jul 2002 A1
20030006901 Kim et al. Jan 2003 A1
20030020661 Sato Jan 2003 A1
20030045324 Nagumo et al. Mar 2003 A1
20030169153 Muller Sep 2003 A1
20030178483 Wakabayashi Sep 2003 A1
20040001027 Killen et al. Jan 2004 A1
20040026519 Usami et al. Feb 2004 A1
20040056823 Zuk et al. Mar 2004 A1
20040066617 Hirabayashi et al. Apr 2004 A1
20040217915 Imaizumi Nov 2004 A1
20040219956 Iwai et al. Nov 2004 A1
20040227673 Iwai et al. Nov 2004 A1
20040252064 Yuanzhu Dec 2004 A1
20050092836 Kudo May 2005 A1
20050099337 Takei et al. May 2005 A1
20050125093 Kikuchi et al. Jun 2005 A1
20050134460 Usami Jun 2005 A1
20050134506 Egbert Jun 2005 A1
20050138798 Sakama et al. Jun 2005 A1
20050140512 Sakama et al. Jun 2005 A1
20050232412 Ichihara et al. Oct 2005 A1
20050236623 Takechi et al. Oct 2005 A1
20050275539 Sakama et al. Dec 2005 A1
20060001138 Sakama et al. Jan 2006 A1
20060044192 Egbert Mar 2006 A1
20060055601 Kameda et al. Mar 2006 A1
20060071084 Detig et al. Apr 2006 A1
20060109185 Iwai et al. May 2006 A1
20060145872 Tanaka et al. Jul 2006 A1
20060158316 Eckstein Jul 2006 A1
20060158380 Son et al. Jul 2006 A1
20060170606 Yamagajo et al. Aug 2006 A1
20060214801 Murofushi et al. Sep 2006 A1
20060220871 Baba et al. Oct 2006 A1
20060244676 Uesaka Nov 2006 A1
20060267138 Kobayashi Nov 2006 A1
20070004028 Lair et al. Jan 2007 A1
20070018893 Kai et al. Jan 2007 A1
20070040028 Kawamata Feb 2007 A1
20070052613 Gallschuetz et al. Mar 2007 A1
20070057854 Oodachi et al. Mar 2007 A1
20070069037 Kawai Mar 2007 A1
20070132591 Khatri Jun 2007 A1
20070164414 Dokai et al. Jul 2007 A1
20070200782 Hayama et al. Aug 2007 A1
20070252700 Ishihara et al. Nov 2007 A1
20070252703 Kato et al. Nov 2007 A1
20070285335 Bungo et al. Dec 2007 A1
20070290928 Chang et al. Dec 2007 A1
20080024156 Arai et al. Jan 2008 A1
20080087990 Kato et al. Apr 2008 A1
20080169905 Slatter Jul 2008 A1
20080272885 Atherton Nov 2008 A1
20090002130 Kato Jan 2009 A1
20090009007 Kato et al. Jan 2009 A1
20090065594 Kato et al. Mar 2009 A1
20090109102 Dokai et al. Apr 2009 A1
20090160719 Kato et al. Jun 2009 A1
20090231106 Okamura Sep 2009 A1
20090262041 Ikemoto et al. Oct 2009 A1
Foreign Referenced Citations (324)
Number Date Country
1447954 Oct 2003 CN
10 2006 057 369 Jun 2008 DE
0 694 874 Jan 1996 EP
0 977 145 Feb 2000 EP
1 010 543 Jun 2000 EP
1 160 915 Dec 2001 EP
1 170 795 Jan 2002 EP
1 227 540 Jul 2002 EP
1 280 232 Jan 2003 EP
1 280 350 Jan 2003 EP
1 343 223 Sep 2003 EP
1 357 511 Oct 2003 EP
1 548 872 Jun 2005 EP
1 703 589 Sep 2006 EP
1 841 005 Oct 2007 EP
2 009 738 Dec 2008 EP
2 148 449 Jan 2010 EP
2 305 075 Mar 1997 GB
50-143451 Nov 1975 JP
62-127140 Aug 1987 JP
02-164105 Jun 1990 JP
03-262313 Nov 1991 JP
04-150011 May 1992 JP
04-167500 Jun 1992 JP
11-88241 Mar 1993 JP
05-327331 Dec 1993 JP
6-53733 Feb 1994 JP
06-077729 Mar 1994 JP
06-177635 Jun 1994 JP
6-260949 Sep 1994 JP
07-183836 Jul 1995 JP
08-056113 Feb 1996 JP
8-87580 Apr 1996 JP
08-088586 Apr 1996 JP
11-149537 Jun 1996 JP
08-176421 Jul 1996 JP
08-180160 Jul 1996 JP
08-279027 Oct 1996 JP
08-307126 Nov 1996 JP
08-330372 Dec 1996 JP
09-014150 Jan 1997 JP
09-035025 Feb 1997 JP
9-93029 Apr 1997 JP
09-245381 Sep 1997 JP
09-252217 Sep 1997 JP
09-270623 Oct 1997 JP
9-512367 Dec 1997 JP
10-069533 Mar 1998 JP
10-69533 Mar 1998 JP
10-505466 May 1998 JP
10-171954 Jun 1998 JP
10-193849 Jul 1998 JP
10-193851 Jul 1998 JP
10-293828 Nov 1998 JP
11-039441 Feb 1999 JP
11-075329 Mar 1999 JP
11-085937 Mar 1999 JP
11-102424 Apr 1999 JP
11-103209 Apr 1999 JP
11-149536 Jun 1999 JP
11-149538 Jun 1999 JP
11-219420 Aug 1999 JP
11-220319 Aug 1999 JP
11-328352 Nov 1999 JP
11-346114 Dec 1999 JP
11-515094 Dec 1999 JP
2000-21128 Jan 2000 JP
2000-021639 Jan 2000 JP
2000-022421 Jan 2000 JP
2005-229474 Jan 2000 JP
2000-059260 Feb 2000 JP
2000-085283 Mar 2000 JP
2000-090207 Mar 2000 JP
2000-132643 May 2000 JP
2000-137778 May 2000 JP
2000-137779 May 2000 JP
2000-137785 May 2000 JP
2000-148948 May 2000 JP
2000-172812 Jun 2000 JP
2000-209013 Jul 2000 JP
2000-222540 Aug 2000 JP
2000-510271 Aug 2000 JP
2000-242754 Sep 2000 JP
2000-243797 Sep 2000 JP
2000-251049 Sep 2000 JP
2000-261230 Sep 2000 JP
2000-276569 Oct 2000 JP
2000-286634 Oct 2000 JP
2000-286760 Oct 2000 JP
2000-311226 Nov 2000 JP
2000-321984 Nov 2000 JP
3075400 Nov 2000 JP
2000-349680 Dec 2000 JP
2001-10264 Jan 2001 JP
2001-028036 Jan 2001 JP
2007-18067 Jan 2001 JP
2001-043340 Feb 2001 JP
2001-66990 Mar 2001 JP
2001-76111 Mar 2001 JP
2001-505682 Apr 2001 JP
2001-168628 Jun 2001 JP
2001-188890 Jul 2001 JP
2001-240046 Sep 2001 JP
2001-256457 Sep 2001 JP
2001-257292 Sep 2001 JP
2001-514777 Sep 2001 JP
2001-319380 Nov 2001 JP
2001-331976 Nov 2001 JP
2001-332923 Nov 2001 JP
2001-339226 Dec 2001 JP
2001-344574 Dec 2001 JP
2001-351084 Dec 2001 JP
2001-352176 Dec 2001 JP
2002-024776 Jan 2002 JP
2002-026513 Jan 2002 JP
2002-32731 Jan 2002 JP
2002-042076 Feb 2002 JP
2002-063557 Feb 2002 JP
2002-505645 Feb 2002 JP
2002-76750 Mar 2002 JP
2002-076750 Mar 2002 JP
2002-150245 May 2002 JP
2002-157564 May 2002 JP
2002-158529 May 2002 JP
2002-175508 Jun 2002 JP
2002-183690 Jun 2002 JP
2002-185358 Jun 2002 JP
2002-204117 Jul 2002 JP
2002-522849 Jul 2002 JP
2002-230128 Aug 2002 JP
2002-232221 Aug 2002 JP
2002-252117 Sep 2002 JP
2002-259934 Sep 2002 JP
2002-280821 Sep 2002 JP
2002-298109 Oct 2002 JP
2002-308437 Oct 2002 JP
2002-319008 Oct 2002 JP
2002-319009 Oct 2002 JP
2002-319812 Oct 2002 JP
2002-362613 Dec 2002 JP
2002-373029 Dec 2002 JP
2002-373323 Dec 2002 JP
2002-374139 Dec 2002 JP
2003-006599 Jan 2003 JP
2003-016412 Jan 2003 JP
2003-026177 Jan 2003 JP
2003-030612 Jan 2003 JP
2003-44789 Feb 2003 JP
2003-046318 Feb 2003 JP
2003-58840 Feb 2003 JP
2003-067711 Mar 2003 JP
2003-069335 Mar 2003 JP
2003-076947 Mar 2003 JP
2003-76963 Mar 2003 JP
2003-78333 Mar 2003 JP
2003-078336 Mar 2003 JP
2003-085501 Mar 2003 JP
2003-085520 Mar 2003 JP
2003-87008 Mar 2003 JP
2003-87044 Mar 2003 JP
2003-099720 Apr 2003 JP
2003-099721 Apr 2003 JP
2003-110344 Apr 2003 JP
2003-132330 May 2003 JP
2003-134007 May 2003 JP
2003-155062 May 2003 JP
2003-158414 May 2003 JP
2003-168760 Jun 2003 JP
2003-179565 Jun 2003 JP
2003-187207 Jul 2003 JP
2003-187211 Jul 2003 JP
2003-188338 Jul 2003 JP
2003-188620 Jul 2003 JP
2003-198230 Jul 2003 JP
2003-209421 Jul 2003 JP
2003-216919 Jul 2003 JP
2003-218624 Jul 2003 JP
2003-233780 Aug 2003 JP
2003-242471 Aug 2003 JP
2003-243918 Aug 2003 JP
2003-249813 Sep 2003 JP
2003-529163 Sep 2003 JP
2003-288560 Oct 2003 JP
2003-309418 Oct 2003 JP
2003-317060 Nov 2003 JP
2003-331246 Nov 2003 JP
2003-332820 Nov 2003 JP
2003-536302 Dec 2003 JP
2004-040597 Feb 2004 JP
2004-505481 Feb 2004 JP
2004-082775 Mar 2004 JP
2004-88218 Mar 2004 JP
2004-93693 Mar 2004 JP
2004-096566 Mar 2004 JP
2004-127230 Apr 2004 JP
2004-213582 Jul 2004 JP
2004-519916 Jul 2004 JP
2004-234595 Aug 2004 JP
2004-253858 Sep 2004 JP
2004-527864 Sep 2004 JP
2004-280390 Oct 2004 JP
2004-287767 Oct 2004 JP
2004-297249 Oct 2004 JP
2004-297681 Oct 2004 JP
2004-319848 Nov 2004 JP
2004-326380 Nov 2004 JP
2004-334268 Nov 2004 JP
2004-336250 Nov 2004 JP
2004-343000 Dec 2004 JP
2004-362190 Dec 2004 JP
2004-362341 Dec 2004 JP
2004-362602 Dec 2004 JP
2005-5866 Jan 2005 JP
2005-18156 Jan 2005 JP
2005-124061 May 2005 JP
2005-128592 May 2005 JP
2005-129019 May 2005 JP
2005-135132 May 2005 JP
2005-136528 May 2005 JP
2005-137032 May 2005 JP
3653099 May 2005 JP
2005-165839 Jun 2005 JP
2005-167327 Jun 2005 JP
2005-167813 Jun 2005 JP
2005-190417 Jul 2005 JP
2005-191705 Jul 2005 JP
2005-210676 Aug 2005 JP
2005-210680 Aug 2005 JP
2005-217822 Aug 2005 JP
2005-236339 Sep 2005 JP
2005-244778 Sep 2005 JP
2005-252853 Sep 2005 JP
2005-275870 Oct 2005 JP
2005-284352 Oct 2005 JP
2005-293537 Oct 2005 JP
2005-295135 Oct 2005 JP
2005-311205 Nov 2005 JP
2005-321305 Nov 2005 JP
2005-322119 Nov 2005 JP
2005-335755 Dec 2005 JP
2005-345802 Dec 2005 JP
2005-346820 Dec 2005 JP
2005-352858 Dec 2005 JP
2006-025390 Jan 2006 JP
2006-031766 Feb 2006 JP
2006-39902 Feb 2006 JP
2006-42059 Feb 2006 JP
2006-42097 Feb 2006 JP
2006-67479 Mar 2006 JP
2006-72706 Mar 2006 JP
2006-80367 Mar 2006 JP
2006-92630 Apr 2006 JP
2006-102953 Apr 2006 JP
2006-107296 Apr 2006 JP
2006-513594 Apr 2006 JP
2006-148518 Jun 2006 JP
2006-151402 Jun 2006 JP
2006-174151 Jun 2006 JP
2006-195795 Jul 2006 JP
2006-203187 Aug 2006 JP
2006-203852 Aug 2006 JP
2006-217000 Aug 2006 JP
2006-232292 Sep 2006 JP
2006-237674 Sep 2006 JP
2006-270212 Oct 2006 JP
2006-270766 Oct 2006 JP
2006-285911 Oct 2006 JP
2006-295879 Oct 2006 JP
2006-302219 Nov 2006 JP
2006-309401 Nov 2006 JP
2006-311239 Nov 2006 JP
2006-323481 Nov 2006 JP
2006-339964 Dec 2006 JP
2007-007888 Jan 2007 JP
2007-13120 Jan 2007 JP
2007-28002 Feb 2007 JP
2007-043535 Feb 2007 JP
2007-048126 Feb 2007 JP
2007-65822 Mar 2007 JP
2007-79687 Mar 2007 JP
2007-81712 Mar 2007 JP
2007-096768 Apr 2007 JP
2007-102348 Apr 2007 JP
2007-122542 May 2007 JP
2007-150642 Jun 2007 JP
2007-150868 Jun 2007 JP
2007-159083 Jun 2007 JP
2007-159129 Jun 2007 JP
2007-228325 Sep 2007 JP
2007-266999 Oct 2007 JP
2007-287128 Nov 2007 JP
2007-312350 Nov 2007 JP
2008-72243 Mar 2008 JP
4069958 Apr 2008 JP
2008-519347 Jun 2008 JP
2008-160874 Jul 2008 JP
11-175678 Jan 2009 JP
2009-25870 Feb 2009 JP
2009-27291 Feb 2009 JP
9100176 Mar 1992 NL
9100347 Mar 1992 NL
9967754 Dec 1999 WO
0010122 Feb 2000 WO
0195242 Dec 2001 WO
02061675 Aug 2002 WO
02097723 Dec 2002 WO
03079305 Sep 2003 WO
2004036772 Apr 2004 WO
2004070879 Aug 2004 WO
2004072892 Aug 2004 WO
2005073937 Aug 2005 WO
2005115849 Dec 2005 WO
2006045682 May 2006 WO
2006048663 May 2006 WO
2007083574 Jul 2007 WO
2007083575 Jul 2007 WO
2007086130 Aug 2007 WO
2007119310 Oct 2007 WO
2007125683 Nov 2007 WO
2007138857 Dec 2007 WO
2008007606 Jan 2008 WO
2008140037 Nov 2008 WO
2009011376 Jan 2009 WO
2009081719 Jul 2009 WO
Non-Patent Literature Citations (96)
Entry
Official communication issued in Japanese Application No. 2007-531524, mailed on Sep. 11, 2007.
Official communication issued in Japanese Application No. 2007-531525, mailed on Sep. 25, 2007.
Official communication issued in Japanese Application No. 2007-531524, mailed on Dec. 12, 2007.
Official communication issued in European Application No. 07706650.4, mailed on Nov. 24, 2008.
Dokai et al.: “Wireless IC Device and Component for Wireless IC Device”; U.S. Appl. No. 11/624,382, filed Jan. 18, 2007.
Dokai et al.: “Wireless IC Device, and Component for Wireless IC Device”; U.S. Appl. No. 11/930,818; filed Oct. 31, 2007.
Kato et al.: “Wireless IC Device”; U.S. Appl. No. 12/042,399; filed Mar. 5, 2008.
Official communication issued in related U.S. Appl. No. 12/042,399; mailed on Aug. 25, 2008.
Official Communication issued in International Application No. PCT/JP2007/066007, mailed on Nov. 27, 2007.
Dokai et al.: “Wireless IC Device and Component for Wireless IC Device”; U.S. Appl. No. 12/359,690, filed Jan. 26, 2009.
Dokai et al.: “Test System for Radio Frequency IC Devices and Method of Manufacturing Radio Frequency IC Devices Using the Same”; U.S. Appl. No. 12/388,826; filed Feb. 19, 2009.
Official Communication issued in International Application No. PCT/JP2008/061955, mailed on Sep. 30, 2008.
Official Communication issued in International Application No. PCT/JP2007/066721, mailed on Nov. 27, 2007.
Official Communication issued in International Application No. PCT/JP2007/070460, mailed on Dec. 11, 2007.
Kato et al.: “Wireless IC Device”; U.S. Appl. No. 12/390,556, filed Feb. 23, 2009.
Kato et al.: “Inductively Coupled Module and Item With Inductively Coupled Module”; U.S. Appl. No. 12/398,497, filed Mar. 5, 2009.
Official Communication issued in International Patent Application No. PCT/JP2008/050945, mailed on May 1, 2008.
Kato et al.: “Article Having Electromagnetic Coupling Module Attached Thereto”; U.S. Appl. No. 12/401,767, filed Mar. 11, 2009.
Taniguchi et al.: “Antenna Device and Radio Frequency IC Device”; U.S. Appl. No. 12/326,117, filed Dec. 2, 2008.
Official Communication issued in International Patent Application No. PCT/JP2008/061442, mailed on Jul. 22, 2008.
Kato et al.: “Container With Electromagnetic Coupling Module”; U.S. Appl. No. 12/426,369, filed Apr. 20, 2009.
Kato: “Wireless IC Device”; U.S. Appl. No. 12/429,346, filed Apr. 24, 2009.
English translation of NL9100176, published on Mar. 2, 1992.
English translation of NL9100347, published on Mar. 2, 1992.
Kato et al.: “Antenna”; U.S. Appl. No. 11/928,502, filed Oct. 30, 2007.
Kato et al.: “Wireless IC Device”; U.S. Appl. No. 12/211,117, filed Sep. 16, 2008.
Kato et al.: “Antenna”; U.S. Appl. No. 11/688,290, filed Mar. 20, 2007.
Kato et al.: “Electromagnetic-Coupling-Module-Attached Article”; U.S. Appl. No. 11/740,509, filed Apr. 26, 2007.
Kato et al.: “Product Including Power Supply Circuit Board”; U.S. Appl. No. 12/234,949, filed Sep. 22, 2008.
Kato et al.: “Data Coupler”; U.S. Appl. No. 12/252,475, filed Oct. 16, 2008.
Kato et al.; “Information Terminal Device”; U.S. Appl. No. 12/267,666, filed Nov. 10, 2008.
Kato et al.: “Wireless IC Device and Wireless IC Device Composite Component”; U.S. Appl. No. 12/276,444, filed Nov. 24, 2008.
Dokai et al.: “Optical Disc”; U.S. Appl. No. 12/326,916, filed Dec. 3, 2008.
Dokai et al.: “System for Inspecting Electromagnetic Coupling Modules and Radio IC Devices and Method for Manufacturing Electromagnetic Coupling Modules and Radio IC Devices Using the System”; U.S. Appl. No. 12/274,400, filed Nov. 20, 2008.
Kato: “Wireless IC Device”; U.S. Appl. No. 11/964,185, filed Dec. 26, 2007.
Kato et al.: “Radio Frequency IC Device”; U.S. Appl. No. 12/336,629, filed Dec. 17, 2008.
Kato et al.: “Wireless IC Device and Component for Wireless IC Device”; U.S. Appl. No. 12/339,198; filed Dec. 19, 2008.
Ikemoto et al.: “Wireless IC Device”; U.S. Appl. No. 11/851,651, filed Sep. 7, 2007.
Kataya et al.: “Wireless IC Device and Electronic Device”; U.S. Appl. No. 11/851,661, filed Sep. 7, 2007.
Dokai et al.: “Antenna and Radio IC Device”; U.S. Appl. No. 12/350,307, filed Jan. 8, 2009.
Official Communication issued in International Patent Application No. PCT/JP2009/056934, mailed on Jun. 30, 2009.
Kato et al.: “Wireless IC Device”; U.S. Appl. No. 12/903,242, filed Oct. 13, 2010.
Kato et al.: “Wireless IC Device”; U.S. Appl. No. 12/940,103, filed Nov. 5, 2010.
Kato et al.: “Wireless IC Device System and Method of Determining Authenticity of Wireless IC Device”; U.S. Appl. No. 12/940,105, filed Nov. 5, 2010.
Official Communication issued in International Patent Application No. PCT/JP2009/059669, mailed on Aug. 25, 2009.
Official Communication issued in International Patent Application No. PCT/JP2009/062181, mailed on Oct. 13, 2009.
Official Communication issued in corresponding Japanese Application No. 2010-501323, mailed on Apr. 6, 2010.
Kato et al.: “Component of Wireless IC Device and Wireless IC Device”; U.S. Appl. No. 12/944,099, filed Nov. 11, 2010.
Kato et al.: Wireless IC Device and Manufacturing Method Thereof; U.S. Appl. No. 12/961,599, filed Dec. 7, 2010.
Kataya et al.: “Radio Frequency IC Device and Electronic Apparatus”; U.S. Appl. No. 12/959,454, filed Dec. 3, 2010.
Ikemoto et al.: Radio IC Device; U.S. Appl. No. 12/981,582, filed Dec. 30, 2010.
Ikemoto et al.: Wireless IC Device and Electronic Apparatus; U.S. Appl. No. 13/022,693, filed Feb. 8, 2011.
Official communication issued in counterpart European Application No. 08 77 7758, dated on Jun. 30, 2009.
Official communication issued in counterpart Japanese Application No. 2008-103741, mailed on May 26, 2009.
Official communication issued in counterpart Japanese Application No. 2008-103742, mailed on May 26, 2009.
Official communication issued in International Application No. PCT/JP2008/050358, mailed on Mar. 25, 2008.
Official communication issed in International Application No. PCT/JP2008/050356, mailed on Mar. 25, 2008.
Osamura et al.: “Packaging Material With Electromagnetic Coupling Module,” U.S. Appl. No. 12/536,663, filed Aug. 6, 2009.
Osamura et al.: “Packaging Material With Electromagnetic Coupling Module,” U.S. Appl. No. 12/536,669, filed Aug. 6, 2009.
Dokai et al.: “Wireless IC Device and Component for Wireless ID Device,” U.S. Appl. No. 12/543,553, filed Aug. 19, 2009.
Shioya et al.: “Wireless IC Device,” U.S. Appl. No. 12/551,037, filed Aug. 31, 2009.
Ikemoto: “Wireless IC Device and Manufacturing Method Thereof,” U.S. Appl. No. 12/579,672, filed Oct. 15, 2009.
Official communication issued in International Application No. PCT/JP2008/058614, mailed on Jun. 10, 2008.
Official communication issued in counterpart International Application No. PCT/JP2008/071502, mailed Feb. 24, 2009.
Kato et al.: “Wireless IC Device and Manufacturing Method Thereof,” U.S. Appl. No. 12/432,854, filed Apr. 30, 2009.
Official communication issued in counterpart International Application No. PCT/JP2008/058168, mailed Aug. 12, 2008.
Official communication issued in counterpart International Application No. PCT/JP2008/062886, mailed Oct. 21, 2008.
Kato et al.: “Wireless IC Device,” U.S. Appl. No. 12/469,896, filed May 21, 2009.
Ikemoto et al.: “Wireless IC Device,” U.S. Appl. No. 12/496,709, filed Jul. 2, 2009.
Official communication issued in counterpart International Application No. PCT/JP2008/062947, mailed Aug. 19, 2008.
Official communication issued in counterpart International Application No. PCT/JP2008/056026, mailed Jul. 1, 2008.
Ikemoto et al.: “Wireless IC Device and Electronic Apparatus,”; U.S. Appl. No. 12/503,188, filed Jul. 15, 2009.
Official communication issued in counterpart International Application No. PCT/JP2008/055567, mailed May 20, 2008.
Official communication issued in counterpart International Application No. PCT/JP2008/051853, mailed Apr. 22, 2008.
Official communication issued in counterpart International Application No. PCT/JP2008/057239, mailed Jul. 22, 2008.
Kimura et al.: “Wireless IC Device,”; U.S. Appl. No. 12/510,338, filed Jul. 28, 2009.
Kato et al.: “Wireless IC Device,”; U.S. Appl. No. 12/510,340, filed Jul. 28, 2009.
Kato: “Wireless IC Device,”; U.S. Appl. No. 12/510,344, filed Jul. 28, 2009.
Kato et al.: “Wireless IC Device,”; U.S. Appl. No. 12/510,347, filed Jul. 28, 2009.
Official Communication issued in International Patent Application No. PCT/JP2008/063025, mailed on Aug. 12, 2008.
Kato et al.: “Wireless IC Device,”; U.S. Appl. No. 12/603,608, filed Oct. 22, 2009.
Kato et al.: “Wireless IC Device,”; U.S. Appl. No. 12/688,072, filed Jan. 15, 2010.
Official Communication issued in International Patent Application No. PCT/JP2009/053693, mailed on Jun. 9, 2009.
Kato: “Composite Antenna,”; U.S. Appl. No. 12/845,846, filed Jul. 29, 2010.
Official Communication issued in International Patent Application No. PCT/JP2009/053690, mailed on Jun. 2, 2009.
Kato et al.: “Radio Frequency IC Device and Radio Communication System,”; U.S. Appl. No. 12/859,340, filed Aug. 19, 2010.
Official Communication issued in International Patent Application No. PCT/JP2009/055758, mailed on Jun. 23, 2009.
Kato et al.: “Wireless IC Device,”; U.S. Appl. No. 12/859,880, filed Aug. 20, 2010.
Official Communication issued in International Patent Application No. PCT/JP2009/057482, mailed on Jul. 21, 2009.
Kataya et al.: “Wireless IC Device, Electronic Apparatus, and Method for Adjusting Resonant Frequency of Wireless IC Device,”; U.S. Appl. No. 12/861,945, filed Aug. 24, 2010.
Kato: “Wireless IC Device and Electromagnetic Coupling Module,”; U.S. Appl. No. 12/890,895, filed Sep. 27, 2010.
Official Communication issued in International Patent Application No. PCT/JP2009/059410, mailed on Aug. 4, 2009.
Kato et al.: “Wireless IC Device”; U.S. Appl. No. 12/902,174, filed Oct. 12, 2010.
Official Communication issued in International Patent Application No. PCT/JP2009/059259, mailed on Aug. 11, 2009.
Official Communication issued in corresponding Japanese Patent Application No. 2010-506742, mailed on Apr. 6, 2010.
Official Communication issued in International Patent Application No. PCT/JP2009/056698, mailed on Jul. 7, 2009.
Related Publications (1)
Number Date Country
20110155810 A1 Jun 2011 US
Provisional Applications (1)
Number Date Country
61016912 Dec 2007 US
Continuations (1)
Number Date Country
Parent 12326117 Dec 2008 US
Child 13043646 US