JP2011254413A - Transmission/reception antenna and transmitter receiver using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission/reception antenna and transmitter receiver using the same, capable of band widening of frequency characteristics and reduction in power consumption.SOLUTION: The transmission/reception antenna includes: a dielectric substrate 11; a loop antenna 12 for excitation mounted on the dielectric substrate 11; a connection terminal 13 for transmission processing part connected to the loop antenna 12 for excitation; a loop antenna 14 for transmission and reception disposed in proximity to the loop antenna 12 for excitation in a contactless state; a capacitor 15 for resonance connected to both ends of the loop antenna 14 for transmission and reception; and a connection terminal 16 for reception processing part connected to the loop antenna 14 for transmission and reception. The loop antenna 12 for excitation has a one-turn loop.

Description

  The present invention supplies power and transmission data to a wireless communication medium such as an IC tag attached to a product or a book or a non-contact IC card used for personal authentication, etc., and receives reception data from the wireless communication medium. The present invention relates to a transmitting / receiving antenna and a transmitting / receiving device using the transmitting / receiving antenna.

  A system generally called a non-contact IC card system uses a frequency band of 13.56 MHz, for example, and is being put into practical use in a logistics system, a traffic system, a merchandise management system, a book management system, a personal authentication system, and the like. .

  Specifically, power and transmission data are supplied from a transmission / reception antenna of a transmission / reception apparatus to a wireless communication medium such as an IC tag attached to a product or a book or a non-contact IC card used for personal authentication.

  Also, reception data from the wireless communication medium is received by the transmission / reception antenna, and is received and processed by the transmission / reception apparatus.

  In recent years, the use of the wireless communication medium has been advanced in the fields of security systems, electronic money, personal authentication, and the like, and even in a situation where a plurality of types of communication systems having different communication systems coexist, a single transmission / reception apparatus can be used. It is desired to respond.

  Therefore, in order to be able to cope with such a request, that is, in a situation where a plurality of types of communication systems having different communication systems coexist, a plurality of resistors are provided in the transmission / reception path of the transmission / reception antenna. There has been proposed a technique for increasing the frequency characteristic bandwidth by interposing and sequentially switching resistors (resistance values) (for example, Patent Document 1 below).

JP 2007-199871 A

  As described above, in the technology disclosed in (Patent Document 1), a plurality of resistors (resistance values) connected to a transmission / reception antenna are sequentially switched to achieve a wide frequency characteristic band. As a result of the constant presence of the resistor, there is a problem that the loss due to the resistor increases the power consumption.

  SUMMARY OF THE INVENTION The present invention has an object to increase the frequency characteristic bandwidth and reduce power consumption.

  In order to achieve this object, the transmitting / receiving antenna of the present invention includes a dielectric substrate, an excitation loop antenna provided on the dielectric substrate, and a transmission processing unit connection terminal connected to the excitation loop antenna. A transmission / reception loop antenna disposed close to the excitation loop antenna in a non-contact state, a resonance capacitor connected to both ends of the transmission / reception loop antenna, and a reception processing unit connected to the transmission / reception loop antenna The excitation loop antenna has a single turn loop, and the transmission / reception loop antenna has an inner loop antenna and a multiple turn outer loop antenna, and the excitation loop antenna Is located between the inner loop antenna and the outer loop antenna, and the pattern of the loop antenna and the excitation loop At least one of the distance between the pattern of the antenna is wider than the distance between the pattern and the pattern of the outer loop antenna, thereby is to achieve the intended purpose.

  The transmission / reception apparatus of the present invention includes the transmission / reception antenna, a transmission processing unit connected to a transmission processing unit connection terminal of the transmission / reception antenna, and a reception processing unit connected to a reception processing unit connection terminal of the transmission / reception antenna. And a receiving unit and a control unit connected to the transmission processing unit, thereby achieving the initial purpose.

  As described above, the transmission / reception antenna of the present invention includes a dielectric substrate, an excitation loop antenna provided on the dielectric substrate, a transmission processing unit connection terminal connected to the excitation loop antenna, and the excitation loop. A transmission / reception loop antenna that is disposed in close proximity to the antenna, a resonance capacitor connected to both ends of the transmission / reception loop antenna, and a reception processing unit connection terminal connected to the transmission / reception loop antenna. The excitation loop antenna has a single turn loop, the transmission / reception loop antenna has an inner loop antenna and a multiple turn outer loop antenna, and the excitation loop antenna is the inner loop antenna. And the outer loop antenna, the pattern of the loop antenna and the pattern of the excitation loop antenna At least one of the spacing between, since the one in which the wider than the distance between the pattern and the pattern of the outer loop antenna can be reduced while achieving a wide band of frequency characteristic, power consumption.

  In other words, in the present invention, the frequency characteristics can be widened by setting the coupling coefficient between the excitation loop antenna and the transmission / reception loop antenna. Since no resistor is interposed in the path, power consumption can be reduced.

  Furthermore, since the excitation loop antenna is configured to have a one-turn loop, and the transmission / reception loop antenna is configured to have a plurality of loops, the power consumption can be reduced also in this respect. it can.

  That is, since the direction of the current flowing through the excitation loop antenna and the direction of the current flowing through the transmission / reception loop antenna are opposite, the magnetic flux generated as a result of the current flowing through the excitation loop antenna is the result of the current flowing through the transmission / reception loop antenna. It will be in the state which weakens the generated magnetic flux.

  For this reason, in this invention, it is trying to suppress that the magnetic flux of a transmission / reception loop antenna is weakened by setting it as the structure which has a loop of 1 turn in the excitation loop antenna.

  Therefore, even if the transmission power from the excitation loop antenna is not increased, a sufficient magnetic flux is generated from the transmission / reception loop antenna, thereby reducing the power consumption.

  The transmission / reception apparatus of the present invention includes the transmission / reception antenna, a transmission processing unit connected to a transmission processing unit connection terminal of the transmission / reception antenna, and a reception processing unit connected to a reception processing unit connection terminal of the transmission / reception antenna. And the reception processing unit and the control unit connected to the transmission processing unit. For the same reason as described above, the frequency characteristics are widened and the power consumption is reduced. be able to.

1 is a block diagram showing a non-contact IC card system according to a first embodiment of the present invention. Perspective view showing the transmitting / receiving antenna Perspective view of the main part of the transmitting / receiving antenna Plan view of the main part of the transceiver antenna Cross-sectional view of the main part of the transmitting / receiving antenna (cross-sectional view taken along the line А-A in FIG. 4) Equivalent circuit diagram that expresses the transceiver antenna using a transformer circuit Equivalent circuit diagram using the coil for the transceiver antenna Frequency characteristics diagram of coupling coefficient K and primary side current I1 of the transmitting / receiving antenna Frequency characteristics diagram of coupling coefficient K and secondary side current I2 of the transmitting / receiving antenna Frequency characteristics diagram of coupling coefficient K, transmission output, and reception sensitivity Frequency characteristics diagram of coupling coefficient K, transmission output, and reception sensitivity Coupling coefficient K of the same transmission / reception antenna and overall communication evaluation chart

  Hereinafter, Embodiment 1 of the present invention will be described with reference to the drawings.

(Embodiment)
FIG. 1 is a block diagram showing a contactless IC card system according to Embodiment 1 of the present invention. For example, using a frequency band of 13.56 MHz, a logistics system, a traffic system, a merchandise management system, a book management system, and a personal authentication are used. It is used for systems.

  Specifically, power and transmission data are supplied from the transmission / reception antenna 3 of the transmission / reception device 2 to the wireless communication medium 1 such as an IC tag attached to a product or a book or a non-contact IC card used for personal authentication or the like. .

  Since the wireless communication medium 1 is a well-known one, the description thereof will be made briefly. The wireless communication medium 1 includes a transmission / reception loop antenna 4 and a control IC (not shown) connected thereto.

  The transmission / reception device 2 includes a control device 6 connected to a network line 5 and a reader / writer device 7 of the control device 6.

  The reader / writer device 7 includes a control unit 8 connected to the control device 6, a reception processing unit 9 and a transmission processing unit 10 connected to the control unit 8.

  Further, the transmission / reception antenna 3 includes a dielectric substrate 11, an excitation loop antenna 12 provided on the surface of the dielectric substrate 11 by printing, and a transmission processing unit connection terminal connected to the excitation loop antenna 12. 13 and the excitation loop antenna 12 are connected to the transmission / reception loop antenna 14 which is arranged in close proximity without contact, the resonance capacitor 15 connected to both ends of the transmission / reception loop antenna 14, and the transmission / reception loop antenna 14. The reception processing unit connection terminal 16 is provided.

  The transmission processing unit 10 is connected to the transmission processing unit connection terminal 13, and the reception processing unit 9 is connected to the reception processing unit connection terminal 16.

  That is, the transmission signal from the transmission processing unit 10 is transmitted to the excitation loop antenna 12 via the filter circuit 10a and the transmission processing unit connection terminal 13, and then transmitted to the transmission / reception loop antenna 14 by magnetic induction. Is transmitted from the loop antenna 14 to the wireless communication medium 1.

  In the wireless communication medium 1, the oscillation signal is received by the transmission / reception loop antenna 4, whereby reception and power supply are performed.

  Next, the transmission signal from the wireless communication medium 1 is received by the transmission / reception loop antenna 14 provided in the transmission / reception antenna 3 of the reader / writer device 7, and this reception signal is then sent from the reception processing unit connection terminal 16 through the filter circuit 9 a. Is transmitted to the reception processing unit 9 via the control unit 8, and is transmitted to the control device 6 via the control unit 8.

  The excitation loop antenna 12 has a single-turned rectangular loop as shown in FIGS. 2 to 5, and the transmission / reception loop antenna 14 has a plurality of turns of a rectangular loop. It is the composition which has.

  More specifically, as shown in FIGS. 2 to 5, the excitation loop antenna 12 includes an inner transmission / reception loop antenna 14 a constituting the transmission / reception loop antenna 14 and an outer transmission / reception antenna disposed outside the loop antenna 14. It arrange | positions between the loop antennas 14b.

  3 to 5 do not dare to describe the dielectric substrate 11 and clarify the structure and mutual relationship between the excitation loop antenna 12 and the transmission / reception loop antenna 14.

  FIG. 6 shows an equivalent circuit in which the transmitting / receiving antenna 3 having the above configuration is replaced by a transformer circuit, and FIG. 7 shows an equivalent circuit using a coil without using the transformer circuit.

  The inductance value L1 shown in FIGS. 6 and 7 represents the inductance value L1 of the excitation loop antenna 12. The inductance value L2 indicates the inductance value L2 of the transmission / reception loop antenna 14.

  A mutual induction M due to electromagnetic coupling exists between the inductance value L1 and the inductance value L2.

  The following (Formula 1) is established between the mutual induction M, the inductance value L1, and the inductance value L2.

M = K × √ (L1 × L2) (Formula 1)
Here, K is a coupling coefficient. K is a value in the range of 0 ≦ K ≦ 1. Therefore, the value of the mutual induction M increases as the coupling coefficient K increases.

  Now, an induced voltage V <b> 2 is generated at the open end of the transmission / reception loop antenna 14 via the mutual induction M due to the magnetic flux generated by the current I <b> 1 flowing through the excitation loop antenna 12. Since the resonance capacitor 15 (C1) is connected to the open end of the transmission / reception loop antenna 14, a current I2 flows through a closed circuit including the inductance L2 and the capacitor C1.

  FIG. 8 shows the result of calculating the relationship between the frequency characteristic of the current I1 flowing through the excitation loop antenna 12 and the coupling coefficient K.

  From FIG. 8, as the value of the coupling coefficient K approaches K = 1, that is, as the value of K increases, the value of the current I1 decreases with the resonance frequency fo as the center. It can be seen that the value of the current I1 is small.

  Next, FIG. 9 shows the result of calculating the relationship between the frequency characteristic of the current I2 flowing through the transmission / reception loop antenna 14 and the coupling coefficient K.

  From FIG. 9, the value of the current I2 decreases as the value of the coupling coefficient K approaches K = 0, that is, the value of K decreases, and the value of the current I2 increases gradually as the value of the coupling coefficient K increases. In addition, the frequency band also spreads around the resonance frequency fo, and K takes a peak value (maximum value) of the current I2 at a certain value, and then the frequency band is gradually decreased while the peak value of the current I2 gradually decreases. You can see that it continues to spread.

  The magnetic flux (magnetic field strength) generated from the excitation loop antenna 12 and the transmission / reception loop antenna 14 will be described.

  In general, the magnetic field intensity H generated by the current I flowing through the coil conductor is expressed by the following (formula 2), where L is the inductance of the coil conductor.

H∝L × I (Formula 2)
That is, the magnetic field strength H is proportional to the product of the inductance value L and the current I flowing through the coil conductor.

  Accordingly, when the magnetic field strength generated by the current I1 flowing through the inductance L1 of the excitation loop antenna 12 at the resonance frequency fo is H1, the magnetic field strength H1 is proportional to the product of the inductance value L1 and the current I1 flowing through the coil conductor. .

  Similarly, when the magnetic field strength generated by the current I2 flowing through the inductance L2 of the transmission / reception loop antenna 14 is H2, the magnetic field strength H2 is proportional to the product of the inductance value L2 and the current I2 flowing through the coil conductor.

  However, as shown in FIG. 4, since the directions of the currents I1 and I2 flow in opposite directions, the directions of the respective magnetic fluxes are also reversed, and a cancellation phenomenon occurs.

  The magnetic field intensity H as the transmission / reception antenna 3 in consideration of the canceling phenomenon is a value obtained by subtracting H1 from the magnetic field H2.

  That is, since the direction of the current flowing through the excitation loop antenna 12 and the direction of the current flowing through the transmission / reception loop antenna 14 are opposite, the magnetic flux generated as a result of the current flowing through the excitation loop antenna 12 is the transmission / reception loop antenna 14. In this state, the magnetic flux generated as a result of the current flowing through is weakened.

  For this reason, in the first embodiment, the excitation loop antenna 12 is configured to have a one-turn loop so as to suppress the magnetic flux of the transmission / reception loop antenna 14 from being weakened.

  For this reason, even if the transmission power from the excitation loop antenna 12 is not increased, a sufficient magnetic flux is generated from the transmission / reception loop antenna 14, thereby reducing the power consumption.

  Further, FIG. 10 shows the frequency characteristic of the first embodiment, which is substantially the same as the value obtained by multiplying the characteristic of the current I2 shown in FIG. 9 by L2.

  Here, FIG. 11 shows a comparison between the conventional example (B line) and the first embodiment (A line) in the case where the resistance R is used to widen the frequency characteristic, as shown in FIG. It can be seen that the transmission power and the reception sensitivity are higher than those of the conventional example, and the frequency characteristics are also wideband.

  That is, in the first embodiment, since no resistor is interposed in the transmission / reception path of the transmission / reception antenna 3 as in the conventional example, power consumption can be reduced.

  In the first embodiment, by adjusting the coupling coefficient K between the excitation loop antenna 12 and the transmission / reception loop antenna 14, the frequency characteristics can be widened.

  Next, the optimum value of the coupling coefficient K will be described with reference to FIG.

  FIG. 12 is a curve showing the transmission performance to the wireless communication medium 1, the reception performance of the response signal from the wireless communication medium 1, and the total performance of the sum, using the coupling coefficient K as a parameter.

  The A line indicates transmission performance, the B line indicates reception performance, and the C line indicates total communication performance.

  Considering based on FIG. 12, the transmission performance (A line) is in the range of K = 0.3 to 0.7, and the reception performance (B line) is in the range of K = 0.5 to 0.9. Is shown.

  Therefore, the coupling coefficient K = 0.5 to 0.7 is optimal for the total communication performance (C line) viewed from both transmission and reception. In the configuration of the first embodiment, approximately K = 0.6, and good communication performance can be obtained.

  Here, the arrangement of the excitation loop antenna 12 and the transmission loop antenna will be described in detail with reference to FIG.

  In the present embodiment, the excitation loop antenna 12 is located between a single-turn inner transmission / reception loop antenna 14a, which is the transmission / reception loop antenna 14, and a multiple-turn outer transmission / reception loop antenna 14b.

  In the present embodiment, the inner transmitting / receiving loop antenna 14a is wound once, but may be wound a plurality of times.

  At this time, the distance (interval) between the wiring pattern (line) of the inner transmission / reception loop antenna 14a and the wiring pattern of the excitation loop antenna 12 is α, the wiring pattern of the excitation loop antenna 12 and the outer transmission / reception loop Assuming that the distance between the wiring pattern of the antenna 14b is β and the distance between the wiring pattern of the outer transmitting / receiving loop antenna 14b is γ, in this embodiment, α> γ and β> γ. It has become.

  Thereby, when finely adjusting the coupling coefficient K described above, it is possible to secure a space for shifting the excitation loop antenna 12 to the inner transmission / reception loop antenna 14a side or to the outer transmission / reception loop antenna 14b side. And K can be easily adjusted.

  In this embodiment, α> γ and β> γ are set. However, α> γ and β ≦ γ (or α ≦ γ and β> γ) may be obtained as a result of fine adjustment.

  That is, in this embodiment, in order to facilitate the adjustment of K, α + β> 2γ is set so that K can be finely adjusted.

  Note that the distance between the wiring pattern of the inner transmitting / receiving loop antenna 14a in the vicinity of the reception processing unit connection terminal 16 and the wiring pattern of the excitation loop antenna 12 is widened so that components and the like can be easily placed. Therefore, it is made smaller than the other parts (γ in this embodiment).

  As described above, according to the first embodiment, with the above configuration, the coupling coefficient K between the excitation loop antenna 12 and the transmission / reception loop antenna 14 is increased, and a large current is caused to flow through the transmission / reception loop antenna 14. As a result, it is possible to realize a wider frequency characteristic.

  In addition, the transmission / reception antenna 3 is formed by printing the excitation loop antenna 12 and the transmission / reception loop antenna 14 on the surface of the dielectric substrate 11, and therefore can be thinned.

  In the above embodiment, the excitation loop antenna 12 and the transmission / reception loop antenna 14 are rectangular loop antennas, but the same effect can be obtained by using a circular or elliptical loop antenna.

  Although the present embodiment has been described as a transmission / reception device, it is configured by simply connecting an IC chip to the transmission processing unit connection terminal 13 and connecting the resonance capacitor 15 to the reception processing unit connection terminal 16. It can also be used as a wireless communication processing medium (IC tag) without the writer device 7 or the like.

  As described above, the transmission / reception antenna of the present invention includes a dielectric substrate, an excitation loop antenna provided on the dielectric substrate, a transmission processing unit connection terminal connected to the excitation loop antenna, and the excitation loop. A transmission / reception loop antenna that is disposed in close proximity to the antenna, a resonance capacitor connected to both ends of the transmission / reception loop antenna, and a reception processing unit connection terminal connected to the transmission / reception loop antenna. The excitation loop antenna has a single turn loop, the transmission / reception loop antenna has an inner loop antenna and a multiple turn outer loop antenna, and the excitation loop antenna is the inner loop antenna. And the outer loop antenna, the pattern of the loop antenna and the pattern of the excitation loop antenna At least one of the spacing between, because the is obtained by a wider configuration than the distance between the pattern and the pattern of the outer loop antenna, it is possible to strive to broadband, thereby lowering power consumption.

  That is, in the present invention, it is possible to increase the bandwidth by setting the coupling coefficient between the excitation loop antenna and the transmission / reception loop antenna, and in order to increase the bandwidth in this way, a resistance is added to the transmission / reception path of the transmission / reception antenna. Since no body is interposed, power consumption can be reduced.

  Furthermore, since the excitation loop antenna is configured to have a one-turn loop, and the transmission / reception loop antenna is configured to have a plurality of loops, the power consumption can be reduced also in this respect. it can.

  In other words, since the current flowing in the excitation loop antenna and the direction of the current flowing in the transmission / reception loop antenna are opposite, the magnetic field generated as a result of the current flowing in the excitation loop antenna is the result of the current flowing in the transmission / reception loop antenna. It becomes a state of weakening the generated magnetic field.

  For this reason, in the present invention, the excitation loop antenna is configured to have a one-turn loop so as to suppress the weakening of the magnetic field of the transmission / reception loop antenna.

  For this reason, even if the transmission power from the excitation loop antenna is not increased, a sufficient magnetic field is generated from the transmission / reception loop antenna, thereby reducing the power consumption.

  In addition, since the transmission / reception antenna is formed by printing the excitation loop antenna and the transmission / reception loop antenna on the surface of the dielectric substrate, the transmission / reception antenna can be reduced in thickness.

  The transmission / reception apparatus of the present invention includes the transmission / reception antenna, a transmission processing unit connected to a transmission processing unit connection terminal of the transmission / reception antenna, and a reception processing unit connected to a reception processing unit connection terminal of the transmission / reception antenna. And the reception processing unit and the control unit connected to the transmission processing unit. For the same reason as described above, the frequency characteristics are widened and the power consumption is reduced. be able to.

  Therefore, since it is possible to widen the frequency characteristics and reduce the thickness of the device, it can be mounted on, for example, a notebook personal computer, a portable information terminal, a mobile phone, or the like.

DESCRIPTION OF SYMBOLS 1 Wireless communication medium 2 Transmission / reception apparatus 3 Transmission / reception antenna 4 Transmission / reception loop antenna 5 Network line 6 Control apparatus 7 Reader / writer apparatus 8 Control part 9 Reception processing part 10 Transmission processing part 11 Dielectric substrate 12 Excitation loop antenna 13 For transmission processing part Connection terminal 14 Transmission / reception loop antenna 14a Inner transmission / reception loop antenna 14b Outer transmission / reception loop antenna 15 Resonance capacitor 16 Reception processing unit connection terminal

In order to achieve this object, the transmitting / receiving antenna of the present invention includes a dielectric substrate, an excitation loop antenna provided on the dielectric substrate, and a transmission processing unit connection terminal connected to the excitation loop antenna. A transmission / reception loop antenna disposed close to the excitation loop antenna in a non-contact state, a resonance capacitor connected to both ends of the transmission / reception loop antenna, and a reception processing unit connected to the transmission / reception loop antenna The excitation loop antenna has a one-turn loop, and the transmission / reception loop antenna has an inner loop antenna and an outer loop antenna configured by a plurality of turns . The excitation loop antenna is arranged with a distance α from the inner loop antenna and a distance β with the outer loop antenna. Therefore, at least one of the distance α and the distance β is made wide on the basis of the distance γ between the patterns of the outer loop antenna , thereby achieving the initial purpose.

Claims (5)

A dielectric substrate, an excitation loop antenna provided on the dielectric substrate, a transmission processing unit connection terminal connected to the excitation loop antenna, and the excitation loop antenna are arranged close to each other in a non-contact state. A transmission / reception loop antenna, a resonance capacitor connected to both ends of the transmission / reception loop antenna, and a reception processing unit connection terminal connected to the transmission / reception loop antenna. The transmission / reception loop antenna includes an inner loop antenna and a multi-turn outer loop antenna, and the excitation loop antenna is positioned between the inner loop antenna and the outer loop antenna. And at least one distance between the pattern of the loop antenna and the pattern of the excitation loop antenna Wider receiving antenna than the distance between the pattern and the pattern of the loop antenna. The transmission / reception antenna according to claim 1 or 2, wherein the inductance value of the excitation loop antenna is L1, the inductance value L2 of the transmission / reception loop antenna is L2, and L2 is 10 times or more of L1 (L2 ≧ 10 × L1). The transmission / reception antenna according to any one of claims 1 to 3, wherein a coupling coefficient K of electromagnetic coupling by mutual induction between the excitation loop antenna and the transmission / reception loop antenna is set to K = 0.5 to 0.7. . The transmission / reception antenna according to any one of claims 1 to 4, wherein the excitation loop antenna is disposed between an inner loop antenna constituting the transmission / reception loop antenna and an outer loop antenna disposed on the outer side thereof. The transmission / reception antenna according to any one of claims 1 to 4, a transmission processing unit connected to a transmission processing unit connection terminal of the transmission / reception antenna, and a reception processing unit connection terminal of the transmission / reception antenna. A transmission / reception apparatus comprising: a reception processing unit; and a control unit connected to the reception processing unit and the transmission processing unit.

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