JP5094630B2 - IC tag - Google Patents

Description

  The present invention relates to an antenna. This technology is effective mainly for use in non-contact electronic devices (hereinafter referred to as IC tags).

  In a non-contact electronic device equipped with an antenna and a semiconductor integrated circuit device, a so-called IC tag exchanges information with a reader / writer device and transmits data held by the IC tag. Various functions such as holding data sent from the network are implemented.

  Specifically, an antenna mounted on an IC tag receives a carrier signal (carrier wave signal) supplied from a reader / writer device, supplies the carrier signal to the semiconductor integrated circuit device, and converts it into a carrier signal within the semiconductor integrated circuit device. The superimposed data is transmitted to the reader / writer device.

  For the carrier signal of the IC tag from the reader / writer device, a frequency band of 860 MHz to 960 MHz, a so-called UHF band high frequency signal or a 13.56 MHz band high frequency signal is mainly used. The 2.45 GHz band is also used.

  As described above, there are a plurality of frequency bands used for IC tags, and the most suitable antenna is selected for each frequency band. However, depending on the principle of operation, there are two types of antennas: a far-field antenna and a near-field antenna. being classified.

  As the antenna mounted on the IC tag used in the UHF band and the 2.45 GHz band, a so-called far-field antenna represented by a dipole antenna is mainly used. A far-field antenna is an antenna that assumes communication between sufficiently distant antennas, and transmits and receives signals by radiation of radio waves or electromagnetic waves.

  On the other hand, when considering using a far-field antenna in the 13.56 MHz band, for example, if a dipole antenna is used, the length of the antenna is 10 meters or more, and it is difficult to apply to an IC tag. For this reason, the antenna mounted on the IC tag is mainly a so-called near-field antenna represented by a loop antenna. In general, a near-field antenna transmits and receives a signal by magnetic field coupling with a coil provided in a reader / writer device using a resonance circuit including a coil and a capacitor. For this reason, it is generally used for short-distance communication rather than communication using a far-field antenna.

  In this way, the type of antenna used depends on the frequency band, and in the case of dealing with a single usage form or usage situation, the optimum frequency band and the corresponding antenna are selected. An IC tag corresponding to only the selected frequency band is used. On the other hand, in the case of using an IC tag corresponding to a single frequency band in a plurality of usage forms or usage situations, considering the propagation characteristics of radio waves or electromagnetic waves, antenna characteristics, the configuration of the reader / writer device, etc., the optimum frequency band There were cases where it was difficult to select.

  For example, an IC tag that uses a high-frequency signal in the UHF band realizes long-distance communication of about several meters by using a far-field antenna in view of propagation characteristics of UHF band electromagnetic waves. For this reason, it is suitable for a usage form such as when an article manager performs collective management of IC tags attached to a large number of articles. However, when another user uses the same IC tag, it is necessary to use a UHF band signal even if the usage form does not require long-distance communication. For this reason, for example, a circuit that drives an antenna in a reader / writer device requires components operable in the UHF band, and it has been difficult to provide an inexpensive reader / writer device.

  In addition, IC tags that use high-frequency signals in the 13.56 MHz band have a lower cost compared to the UHF band, but the near-field antenna is used for communication between the IC tag and the reader / writer apparatus. Communication distance is shortened. For this reason, it is disadvantageous for use forms that require long-distance communication, such as when the article manager performs batch management of IC tags attached to a large number of articles.

  As described above, it is necessary to select a suitable carrier signal and antenna according to the usage form of the IC tag. However, when there are a plurality of usage forms, a far-field antenna having a different antenna operating principle is used. Since it is difficult to design an antenna corresponding to both the frequency band and the frequency band using the near-field antenna, it is difficult to support the IC tag in a plurality of frequency bands according to each usage form. . As means for solving this problem, techniques such as Patent Document 1, Patent Document 2, and Patent Document 3 are disclosed.

  The technology disclosed in Patent Document 1 includes a far-field antenna for data transmission / reception and a near-field antenna for power supply, and is connected to a data transmission / reception terminal and a power supply terminal in a semiconductor integrated circuit, respectively. By using an IC tag with a configured configuration and using a conventional IC tag using a battery as a power supply source, the IC tag can be operated for a long time by supplying power from a near-field antenna without using a battery. It is a technology that realizes that.

  The technique disclosed in Patent Document 2 is an antenna that controls the shape of a near-field antenna and enables transmission and reception of carrier signals in a frequency band used in a far-field antenna, so-called UHF band and 2.45 GHz band. This is a technique that enables transmission and reception of signals in a plurality of frequency bands with a single antenna.

  The technique disclosed in Patent Document 3 includes a near-field antenna and a far-field antenna, which is configured by connecting the near-field antenna and the far-field antenna, and connecting the far-field antenna and the semiconductor integrated circuit. And antenna means that operates in respective frequency bands used by the far-field antenna.

JP-A-5-290229 JP 2006-309476 A JP-T-2004-513404

  An IC tag corresponding to a plurality of frequency bands as disclosed in Patent Document 1 includes an antenna corresponding to each carrier signal for a plurality of carrier signals, and connects each antenna. On the top, antenna terminals were provided for each antenna. For this reason, it is difficult to use an existing semiconductor integrated circuit as it is based on the assumption that there is only one antenna to be connected. In addition, the increase in the number of antenna terminals increases the number of antenna connection portions and the density of the antenna connection portions, which necessitates an increase in chip size, miniaturization of the antenna manufacturing process, and the like.

  The antenna shown in Patent Document 2 is adjusted to operate in the UHF band by limiting the shape of the near-field antenna. For this reason, an IC tag corresponding to a plurality of frequency bands can be provided without increasing the number of terminals of the semiconductor integrated circuit. However, it is necessary to make the antenna a predetermined size, It is difficult to adjust the size and shape in accordance with the characteristics and the like, and it has been difficult to provide an antenna having an optimum characteristic according to the usage form and situation for each frequency band.

  The antenna disclosed in Patent Document 3 can provide an IC tag corresponding to a plurality of frequency bands without adding a terminal of a semiconductor integrated circuit by combining a far-field antenna and a near-field antenna. The shape and size of the near-field antenna has a great influence on the far-field antenna, and it has been difficult to design the near-field antenna and the far-field antenna independently. For this reason, it is difficult to optimize the design and antenna characteristics, and it has been difficult to provide an antenna having the optimal characteristics according to the usage pattern and situation.

  An object of the present invention is to provide an antenna that can be optimally designed and adjusted individually for each non-contact electronic device (IC tag) that operates with high-frequency signals in a plurality of frequency bands, particularly in each frequency band. It is to be.

  The outline of a typical invention among the inventions disclosed in the present application will be briefly described as follows.

  That is, a semiconductor integrated circuit including a transmission / reception circuit, a far-field antenna that transmits and receives at a first frequency, and a near-field antenna that transmits and receives at a second frequency, and the near-field antenna passes through the far-field antenna. To the semiconductor integrated circuit.

  The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.

  In other words, optimum design and adjustment can be made individually for each of a plurality of frequency bands used by the antenna of the non-contact electronic device.

Hereinafter, an IC tag of the present invention will be described with reference to the accompanying drawings.
FIG. 1 shows an example of an IC tag system of the present invention. The IC tag L1 communicates with the first reader / writer device R1 by radio waves or electromagnetic waves. The IC tag L1 communicates with the second reader / writer device R2 by magnetic field coupling.

  FIG. 2 shows a first embodiment of the IC tag L1 shown in FIG. The IC tag L1 includes a far field antenna A1, an antenna L2, a semiconductor integrated circuit device B1, and a substrate S1. Here, the far-field antenna means an antenna that transmits and receives signals by radiating radio waves or electromagnetic waves, and the near-field antenna means an antenna that transmits and receives signals by magnetic field coupling with the coil of the reader / writer device. (The same shall apply in the following description).

  The semiconductor integrated circuit device B1 has antenna terminals LA and LB connected to the multi-antenna. Since the near-field antenna L2 and the semiconductor integrated circuit B1 form a resonance circuit, between the antenna terminals LA and LB at the connection point between the near-field antenna L2 and the antenna terminal LA and at the connection point between the near-field antenna L2 and the antenna terminal LB. It is configured not to be electrically short-circuited.

  The antenna L2 is formed on one or both metal layers of the substrate S1, and the semiconductor integrated circuit device B1 is connected to the antenna terminals LA and LB at two points on the antenna L2.

  FIG. 3 shows an example of the configuration of the semiconductor integrated circuit B1 in the IC tag L1 shown in FIG. The semiconductor integrated circuit B1 has antenna terminals LA and LB for connection between the far-field antenna A1 and the near-field antenna L2. When a carrier signal (carrier wave signal) is input to the antenna terminals LA and LB of the semiconductor integrated circuit B1, the carrier signal is transmitted to the power supply circuit B2 (PWR) and the signal processing circuit B3 (SP). The power supply circuit B2 generates a voltage and a current for operating the signal processing circuit from the carrier signals supplied from the antenna terminals LA and LB, and supplies the voltage and current to the signal processing circuit B3. The signal processing circuit B3 demodulates the data of the carrier signal supplied from the antenna terminals LA and LB via the transmission / reception circuit B4 (TR), or the data held in the antenna terminal via the transmission / reception circuit B4. It transmits by modulating the signal supplied to LA and LB.

  FIG. 4 shows a far-field antenna A1 in the IC tag L1 in FIG. The far-field antenna A1 is formed by a radiation part A2 and an impedance adjustment part A3. The far-field antenna A1 is generally configured as a half-wave dipole antenna. When the far-field antenna A1 receives the electromagnetic wave by the radiation part A2, the far-field antenna A1 transmits the carrier signal to the antenna terminals LA and LB via the impedance adjustment part A3. The carrier signal input from the semiconductor integrated circuit B1 to the antenna terminals LA and LB is transmitted to the radiating unit A2 through the impedance adjusting unit A3. When the carrier signal is a signal in a frequency band used in the radiating unit A2, the carrier signal is radiated as an electromagnetic wave from the radiating unit A2.

  In order for the far-field antenna A1 not to interfere with the operation of the near-field antenna L2, the near-field antenna L2 and the semiconductor integrated circuit B1 need to form a resonance circuit, and the far-field antenna A1 does not short-circuit the antenna terminals LA and LB. Must be an antenna. The frequency band in which the far field antenna is used is generally the UHF band or 2.45 GHz band, while the frequency band in which the near field antenna is used is generally the 13.56 MHz band. In view of this, the far-field antenna A1, which is an unshorted structure having a wavelength of about UHF band or 2.45 GHz band, is sufficiently small with respect to the wavelength of the carrier signal frequency of the near-field antenna unit. Do not disturb the L2 carrier signal. As the antenna used for the far-field antenna A1, a dipole antenna or the like is preferable in consideration of not short-circuiting the antenna terminals LA and LB and directivity.

  The impedance adjustment unit A3 is mounted between the semiconductor integrated circuit B1 and the radiation unit A2 in order to match the impedance of the radiation unit A2 and the impedance of the semiconductor integrated circuit B1. When the signal given to the antenna terminals LA and LB by the semiconductor integrated circuit B1 is in the operating frequency band of the far-field antenna A1, it is transmitted by the impedance adjusting unit A3 to the radiating unit A2 without loss and radiated from the radiating unit A2. The Further, the carrier signal received by the radiating unit A2 is also transmitted to the impedance adjusting unit A3 and transmitted to the semiconductor integrated circuit B1 via the antenna terminals LA and LB without loss. Furthermore, since the impedance adjustment unit A3 is sufficiently small with respect to the frequency band used in the near-field antenna L2, generally, the wavelength of the electromagnetic wave in the 13.56 MHz band, the impedance adjustment unit A3 is used in the near-field antenna L2. The transmission of the signal in the frequency band to be transmitted through the impedance adjustment unit A3 is not disturbed.

  FIG. 5 shows a near-field antenna L2 in the IC tag L1 in FIG. The near-field antenna L2 is connected to the semiconductor integrated circuit B1 through the radiation part A2 and the impedance adjustment part A3. The near-field antenna L2 connects the points M2 and M3 with a bridge M1. The near-field antenna L2 is generally a coil and forms a resonance circuit together with the semiconductor integrated circuit B1. When the carrier signal is transmitted to the near-field antenna L2 by a magnetic field, when the resonance frequency of the resonance circuit is close to the frequency of the carrier signal, the carrier signal is often transmitted to the semiconductor integrated circuit B1 via the antenna terminals LA and LB. When the resonance frequency is sufficiently separated from the frequency of the carrier signal, the carrier signal is not transmitted to the semiconductor integrated circuit B1 through the antenna terminals LA and LB. When the carrier signal is transmitted from the antenna terminals LA and LB from the semiconductor integrated circuit B1, if the resonance frequency of the resonance circuit is close to the frequency of the carrier signal, the carrier signal is passed through the near-field antenna L2 to the reader / writer. When the resonance frequency is well transmitted to the apparatus and sufficiently separated from the frequency of the carrier signal, the carrier signal is not transmitted to the reader / writer apparatus via the near-field antenna L1.

  For example, when a high frequency signal in the 13.56 MHz band is used as the carrier signal, the resonance frequency of the resonance circuit composed of the near-field antenna L1 and the semiconductor integrated circuit B1 is generally about 12 MHz to 15 MHz. Is set. Thus, the 13.56 MHz band carrier signal is received by the near-field antenna L2, and transmitted to the semiconductor integrated circuit B1 via the antenna terminals LA and LB. The 13.56 MHz band carrier signal input to the antenna terminals LA and LB is transmitted to the reader / writer device via the near-field antenna L2.

  FIG. 6 shows a radiation portion A2 in the far-field antenna A1 in the IC tag L1 in FIG. Here, the radiation part A2 is also a filter element including the first terminal pair P1 and the second terminal pair P2.

  FIG. 7 is a graph in which the signal transmission characteristics (hereinafter referred to as S12 parameters) to the second terminal pair P2 with respect to the first terminal pair P1 in the radiating portion A2 are represented by the frequency (Frequency) on the horizontal axis and the S12 parameter on the vertical axis. An example is shown. The frequency f is a frequency at which transmission / reception is performed by the far-field antenna A1.

  In the vicinity of the frequency f, transmission of the signal input to the first terminal pair P1 to the second terminal pair P2 is suppressed. At a frequency sufficiently away from the frequency f, the signal input to the first terminal pair P1 is transmitted to the second terminal pair P2. That is, the radiating portion A2 functions as a so-called band-elimination filter (band-elimination filter). Further, the signal transmission characteristic (hereinafter referred to as S21 parameter) to the first terminal pair P1 with respect to the second terminal pair P2 is such that the radiating portion A2 is symmetrical with respect to the first terminal pair P1 and the second terminal pair P2. Since it has a shape, it is the same as the S12 parameter. The S12 parameter and the S21 parameter indicate the same S12 parameter and S21 parameter when the radiating portion A2 is configured by a so-called half-wave dipole antenna, and operate as a so-called band-eliminating filter.

  For example, when a so-called 953 MHz band belonging to the UHF band is selected as the operating frequency band of the far-field antenna, the characteristics as the filter of the radiating portion A2, that is, the S12 parameter and the S21 parameter are set to be minimal values near 953 MHz. Is done. In order to set the minimum values of the S12 parameter and the S21 parameter to be near 953 MHz, the length of the radiating portion A2 may be set to about a half wavelength (half wavelength dipole) of the carrier signal in the selected band. The length of the radiating portion A2 may be an integral multiple of a half wavelength of the carrier signal in the selected band.

  In this way, for example, when a carrier signal in the 953 MHz band is input to the antenna terminals LA and LB, the carrier signal is radiated in the form of electromagnetic waves in the radiating section A2, and is not transmitted to the near-field antenna L2. For example, when a 13.56 MHz carrier signal is input to the antenna terminals LA and LB, the carrier signal is transmitted to the near-field antenna L2 without being radiated as an electromagnetic wave by the radiating unit A2.

  The reception operation will be described. When the reader / writer device emits electromagnetic waves in the frequency band, UHF band, or 2.45 GHz band used in the far-field antenna A1, a carrier signal is received by the radiating unit A2. The carrier signal received by the radiation unit A2 is transmitted to the semiconductor integrated circuit device B1 via the antenna terminals LA and LB via A3 due to the effect of the impedance adjustment unit A3. On the other hand, since the impedance of the near-field antenna L2 and the impedance of the radiating portion A2 are not matched, the carrier signal transmitted from the radiating portion A2 to the near-field antenna L2 is extremely small. When a carrier signal is transmitted to the near-field antenna L2 by an electromagnetic wave in the frequency band used in the far-field antenna A1, generally UHF band or 2.45 GHz band, the second terminal pair P2 is transmitted from the near-field antenna L2. The carrier signal is transmitted to the first terminal pair P1 from the second terminal pair P2 to the first terminal pair P1 according to the characteristics of the S21 parameter because the radiating portion A2 is a filter element that blocks the carrier signal. The carrier signal transmitted from the antenna L2 to the second terminal pair P2 is extremely small. Therefore, the operation of the far-field antenna A1 is not disturbed by the near-field antenna L2.

  Further, when a carrier signal in the frequency band used by the near-field antenna L2 is transmitted from the reader / writer device to the near-field antenna L2 by magnetic field coupling, the first signal is transmitted from the near-field antenna L2 via the second terminal pair P2. It is transmitted to one terminal pair P1. At this time, radiation by the radiation part A2 is extremely small, and the carrier signal is transmitted from the second terminal pair P2 to the first terminal pair P1 with low loss. A signal is transmitted from the first terminal pair P1 to the antenna terminals LA and LB via the impedance adjuster A3. At this time, since the transmission of the carrier signal is not disturbed by the impedance adjuster A3, the antenna terminal LA is reduced in loss. And transmitted to LB.

  The carrier signals transmitted to the antenna terminals LA and LB are transmitted to the semiconductor integrated circuit B1, and are respectively transmitted to the power supply circuit B2 and the signal processing circuit B3 in the semiconductor integrated circuit B1. The signal processing circuit B3 operates by supplying the voltage and current generated in the power supply circuit B2 to the signal processing circuit B3. On the other hand, the signal superimposed on the carrier signal is transmitted to the transmission / reception circuit B4, the transmission / reception circuit B4 demodulates the superimposed signal, and the signal processing circuit B3 performs processing based on the demodulated signal.

  With the above operation, it is possible to receive a carrier signal and a signal superimposed thereon via an optimum antenna at a plurality of carrier signal frequencies.

  Furthermore, since the far field antenna A1 and the near field antenna L2 do not interfere with each other by the radiating portion A2 that is a filter element, it is possible to design the reception operation individually and optimally. It is possible to provide an optimum antenna in accordance with the usage form in each frequency band.

  A transmission operation will be described. When the carrier signal input via the antenna terminals LA and LB by the semiconductor integrated device B1 has a carrier frequency in the vicinity of f, that is, the frequency band in which the far-field antenna A1 operates, generally the UHF band or 2.45 GHz. If it is a band, it is transmitted to the impedance adjusting unit A3, transmitted from the impedance adjusting unit A3 to the first terminal pair P1 of the radiating unit A2, and transmitted from the first terminal pair P1 of the radiating unit A2 to the radiating unit A2. The radiation part A2 radiates as an electromagnetic wave, and the radiated electromagnetic wave propagates through the space between the reader / writer and is transmitted to the reader / writer device. On the other hand, since transmission from the radiating portion A2 to the second terminal pair P2 is suppressed, the carrier signal input to the antenna terminals LA and LB is mainly radiated portion A2 regardless of the shape and size of the near-field antenna. More radiated as electromagnetic waves. Accordingly, the operation of the far-field antenna A1 is not hindered by the near-field antenna L2.

  Further, when the frequency of the carrier signal input to the antenna terminals LA and LB is near the resonance frequency of the near-field antenna, the signal transmitted to the first terminal pair P1 is not radiated as an electromagnetic wave in the radiating portion A2. , Transmitted to the second terminal pair P2. The carrier signal transmitted from the second terminal pair P2 to the near-field antenna L2 is transmitted to the reader / writer device by magnetic field coupling between the near-field antenna L2 and the antenna provided in the reader / writer device.

  With the above operation, signals can be transmitted via an optimum antenna at a plurality of carrier signal frequencies. Furthermore, since the far-field antenna A1 and the near-field antenna L2 do not interfere with each other's transmission operation by the radiating portion A2 that is a filter element, it is possible to individually design each transmission operation optimally. With the above reception operation and transmission operation, it is possible to design and provide an optimum antenna in accordance with the usage form in each frequency band in the frequency band in which the far-field antenna A1 and the near-field antenna L2 operate. Become.

  FIG. 8 shows a second embodiment of the IC tag L1. The embodiment in FIG. 8 has a configuration in which a resonance capacitor C1 is added to the first embodiment shown in FIG.

  The near-field antenna L2 generally has a coil shape, and an appropriate size, shape, and number of turns are selected according to the usage form of the IC tag. When the dimensions, shape, and number of turns of the coil of the near-field antenna L2 are changed, the resonance frequency of the near-field antenna L2 changes. Therefore, by changing the dimension of the resonance capacitor C1, it is possible to change the capacitance value of the resonance capacitor C1 and adjust the resonance frequency to a desired resonance frequency. In order not to disturb the operation, it is desirable to take a sufficiently small value in the frequency band used by the far-field antenna A1. Further, by arranging the resonance capacitor C1 as shown in FIG. 8, the near-field antenna L2 has a coil portion having the same size, shape and number of turns as compared with the third embodiment shown in FIG. In this case, a larger inductance can be obtained, and the resonant capacitor C1 or the near-field antenna L2 can be downsized.

  FIG. 9 shows an example of a cross section at x1 in FIG. The near-field antenna L2 includes a first metal C2, a substrate S1, and a second metal layer C4. The substrate S1 is a dielectric. The near-field antenna L2 is configured on the first metal layer C2 except for the bridge M1 and the resonant capacitor C1, the bridge M1 is configured on the second metal layer C4, and the resonant capacitor C1 is connected to the first metal layer C2. It is a thin film capacitor constituted by the substrate S1 and the second metal layer C4. The bridge M1 is connected to the first metal layer C2 at points M2 and M3. Between the points M2 and M3 of the bridge M1, a second metal layer portion of the resonance capacitor C1 is formed.

  FIG. 10 shows a third embodiment of the IC tag. As in the second embodiment shown in FIG. 8, this embodiment has a configuration in which a resonance capacitor C1 is added to the first embodiment shown in FIG. Compared with the second embodiment, the method of adding the resonance capacitor C1 is different.

  The near-field antenna L2 generally has a coil shape, and an appropriate size, shape, and number of turns are selected according to the usage form of the IC tag. When the dimensions, shape, and number of turns of the coil of the near-field antenna L2 are changed, the resonance frequency of the near-field antenna L2 changes. For this reason, by changing the dimension of the resonance capacitor C1, the capacitance value of the resonance capacitor C1 can be changed and adjusted to a desired resonance frequency.

  By connecting the resonance capacitor C1 to the first metal layer C2 at points M4 and M5, an electrical path that is not negligible compared to the wavelength of the frequency band used by the far-field antenna A1 can be obtained. By being present between C1 and the radiating portion A2, the resonant capacitor C1 and the radiating portion A2 are not easily matched. For this reason, when the capacitance value of the resonance capacitor C1 is changed, the influence on the radiation part A2 is small, and the resonance capacitor C1 can be designed without considering the influence on the radiation part A2.

  FIG. 11 shows a cross section at x2 in FIG. The near-field antenna L2 is generally composed of a first metal C2, a substrate S1, and a second metal layer C4. The substrate S1 is a dielectric. The near-field antenna L2 is configured on the first metal layer C2 except for the bridge M1 and the resonant capacitor C1, the bridge M1 is configured on the second metal layer C4, and the resonant capacitor C1 is connected to the first metal layer C2. It is a thin film capacitor constituted by the substrate S1 and the second metal layer C4. The bridge M1 is connected to the first metal layer C2 at points M2 and M3.

  The resonance capacitor C1 is preferably formed inside the near field antenna L2 in order to reduce the size of the IC tag L1, but may be formed outside the near field antenna L2. The first metal layer C2 in the resonance capacitor C1 is connected to the near-field antenna L2 at the point M4, and the second gold enhancement layer C4 is connected to the near-field antenna L2 at the point M5.

  By arranging the resonant capacitor C1 as shown in FIG. 10, the influence on the radiation part A2 when the capacitance value of the resonant capacitor C1 is changed is small compared to the second embodiment shown in FIG. Therefore, it is possible to design the resonance capacitor C1 without considering the influence on the radiation part A2.

  FIG. 12 shows a fourth embodiment of the IC tag. The embodiment in FIG. 12 has a configuration in which the radiating portion A2 in the far field antenna A1 is changed to a so-called meander shape in the first embodiment shown in FIG. The far-field antenna A1 is formed by a radiation part A2 and an impedance adjustment part A3. The radiating portion A2 is a dipole antenna having a meander-shaped portion A4. The far-field antenna A1 can be downsized while having almost the same performance by including the meander-shaped portion A4.

  FIG. 13 shows a fifth embodiment of the IC tag. The embodiment in FIG. 13 is obtained by changing the radiating portion A2 in the far-field antenna A1 to a configuration having a so-called spiral inductor in the first embodiment shown in FIG. The far-field antenna A1 is formed by a radiation part A2 and an impedance adjustment part A3. The radiating portion A2 is a dipole antenna including a spiral inductor A5. The far-field antenna A1 can be reduced in size while having substantially the same performance by including the spiral inductor A5 as compared with the far-field antenna A1 in the first embodiment of the present invention. .

  FIG. 14 shows a sixth embodiment of the IC tag. The embodiment in FIG. 14 has a configuration in which a filter F1 is added to the first embodiment shown in FIG. In general, the filter F1 is preferably a band-eliminated filter, but may be a low-pass filter. Compared with the signal transmission characteristic of the radiation part A2 in the first embodiment, it is possible to widen the band and improve the separation characteristic. In addition, even when a plurality of frequencies are used in a frequency band that can be used by the far-field antenna A1, a filter having an optimum separation characteristic can be used regardless of the frequency.

  FIG. 15 shows a filter F1 in the IC tag L1 of FIG. The filter F1 has a first terminal pair P3 and a second terminal pair P4, and the first terminal pair P3 is connected to the second terminal pair P2 of the radiating portion A2.

  FIG. 16A shows signal transfer characteristics (hereinafter referred to as S12 parameter) to the second terminal pair P2 with respect to the first terminal pair P1 in the radiation part A2 of the IC tag L1 in FIG. 13, and the horizontal axis represents the frequency (Frequency). ), An example of a graph representing the S12 parameter on the vertical axis is shown. The frequency f1 is a frequency that gives a minimum value in the S12 parameter. FIG. 16A basically shows the same characteristics as FIG.

  FIG. 16B shows the signal transfer characteristic (hereinafter referred to as S34 parameter) to the second terminal pair P4 with respect to the first terminal pair P3 of the filter F1, the horizontal axis represents frequency (Frequency), and the vertical axis represents S34 parameter. An example of the represented graph is shown. The frequency f2 represents the frequency that gives the minimum value in the S34 parameter.

  In the vicinity of the frequency f2, transmission of the signal input to the first terminal pair P3 of the filter F1 to the second terminal pair P4 is suppressed. At a frequency sufficiently away from the frequency f, the signal input to the first terminal pair P3 of the filter F1 is transmitted to the second terminal pair P4. Further, the signal transmission characteristic (hereinafter referred to as S43 parameter) to the first terminal pair P1 with respect to the second terminal pair P2 of the filter F1 is such that the radiating unit A2 has the first terminal pair P1 and the second terminal pair P2. Since it has a symmetric shape, it is the same as the S34 parameter.

  FIG. 16C shows the signal transfer characteristic (hereinafter referred to as S14 parameter) to the second terminal pair P4 of the filter F1 with respect to the first terminal pair P1 of the radiating portion A2, and the horizontal axis indicates the frequency (Frequency) and the vertical axis. An example of the graph which expressed S14 parameter on the axis | shaft is shown. The S14 parameter, which is the signal transfer characteristic of the configuration in which the radiating part A2 and the filter F1 are connected, is as shown in FIG. 16C, and compared with the signal transfer characteristic S12 of the radiating part A2 in the first embodiment, Broadband and improved separation characteristics are possible. By doing so, for example, even when a plurality of frequencies are used in a frequency band that can be used by the far-field antenna A1, a filter having an optimum separation characteristic can be used regardless of the frequency.

  Although the invention made by the present inventor has been specifically described based on the embodiments, it is needless to say that the present invention is not limited to the embodiments and can be variously modified without departing from the gist thereof. Yes.

  The present invention is suitable for application to non-contact electronic devices, so-called IC tags and the like.

It is an example of an IC tag system. It is a 1st Example of an IC tag. It is an example of a semiconductor integrated circuit. It is an Example of a far-field antenna part. It is an Example of a near field antenna part. It is an Example of the radiation | emission part in a far field antenna part. It is an example of the signal transmission characteristic in the radiation | emission part of a far-field antenna part. It is a 2nd Example of an IC tag. It is an Example of the resonant capacity in a near field antenna part. It is a 3rd Example of an IC tag. It is an Example of the resonant capacity in a near field antenna part. It is a 4th Example of an IC tag. It is a 5th Example of an IC tag. It is a 6th Example of an IC tag. It is an Example of a filter part. It is an example of the signal transmission characteristic in the radiation | emission part of a filter part and a far-field antenna part.

Explanation of symbols

A1-3 ... Far-field antenna B1-3 ... Semiconductor integrated circuit C1 ... Resonant capacitance L1 ... IC tag L2 ... Near-field antenna LA, LB ... Antenna terminals M1-5 ... Bridge R1-2 ... Reader / writer device S1 ... Substrate

Claims (7)

A semiconductor integrated circuit including a transceiver circuit;
A far-field antenna that transmits and receives with a first carrier signal of a first frequency;
A near-field antenna that transmits and receives with a second carrier signal of a second frequency,
The far-field antenna is an antenna that transmits and receives signals by radiating radio waves,
The near-field antenna is an antenna that transmits and receives signals by magnetic field coupling with a reader / writer coil,
The IC tag, wherein the near-field antenna is connected to the semiconductor integrated circuit through the far-field antenna. The IC tag according to claim 1,
The far-field antenna functions as a band elimination filter,
An IC tag having low signal transfer characteristics in the first frequency band between the far-field antenna, the semiconductor integrated circuit, and the near-field antenna. The IC tag according to claim 1 or 2,
The IC tag, wherein the far-field antenna has a half-wavelength of the first carrier signal. In the IC tag according to any one of claims 1 to 3,
Have a filter,
The near-field antenna is connected to the semiconductor integrated circuit through the filter,
The IC tag, wherein the filter has a low signal transfer characteristic in a band of the first frequency between the semiconductor integrated circuit and the near-field antenna. The IC tag according to any one of claims 1 to 4,
The IC tag, wherein the far-field antenna has a meander shape. The IC tag according to any one of claims 1 to 4,
The IC tag, wherein the far-field antenna is a spiral antenna. It has a reader / writer and an IC tag,
The IC tag includes a semiconductor integrated circuit including a transmission / reception circuit, a far-field antenna that transmits and receives a first carrier signal having a first frequency, and a near-field antenna that transmits and receives a second carrier signal having a second frequency. ,
The far-field antenna is an antenna that transmits and receives signals by radiating radio waves,
The near-field antenna is an antenna that transmits and receives signals by magnetic field coupling with a reader / writer coil,
The near-field antenna is connected to the semiconductor integrated circuit via the far-field antenna,
An IC tag system, wherein the semiconductor integrated circuit communicates with the reader / writer via the far-field antenna or the near-field antenna.

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