JP2000286630A - Transmitter and receiver antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a defective case where the signals radiated from a transmitter antenna creeping to a receiver antenna to deteriorate the receiving performance by placing a cancel coil consisting of a loop antenna on the outer concentric axis of a transmitter antenna and winding the cancel coil in opposite winding direction to the receiver antenna. SOLUTION: A receiver antenna wire 52 serving as the coil end of a receiver antenna 15 is passed through a wire hole 63 of a flange 40a (corresponding to a transmitter antenna 13) of an antenna bobbin 40 and is wound in the opposite winding direction to the antenna 15, i.e., in the winding direction S4. The wire 52 is wound in piles and its coil end is passed through a wire hole 64 from the groove side to the outside of the flange 40a and then through a wire hole 66 from the groove side to the outside of a flange 40b. Thus, the creeping components of the signals radiated from the antenna 13 and observed at the antenna 15 can be completely eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is provided in a reader / writer for communicating with a wireless card or a wireless tag,
The present invention relates to a transmitting / receiving antenna including a transmitting antenna and a receiving antenna.

[0002]

2. Description of the Related Art Wireless cards or wireless tags (hereinafter, referred to as wireless tags)
The communication area in the communication between the card and the reader / writer depends largely on the position of the transmission / reception antenna of the reader / writer, the transmission output, and the reception sensitivity, and furthermore, the reception and transmission performance of the card. Depends on.

There are two types of cards: a built-in battery type and a batteryless type.
The antenna configuration of the reader / writer includes a type having a dedicated transmitting and receiving antenna and a type having a single transmitting and receiving antenna. When the reader / writer is sending data to the card, there is no response from the card, and when the card is responding, the reader / writer performs reception only. There is a full-duplex communication method in which data is exchanged bidirectionally.

As described above, when the transmitting and receiving antennas of the reader / writer are individually dedicated, the card and
The communication area in the inter-reader / writer communication largely depends on the position of the transmitting / receiving antenna of the reader / writer. This is because the positions of the transmitting antenna and the receiving antenna of the reader / writer are geometrically separated from each other.

[0005] Even if the card is present at a position where the signal radiated from the transmission antenna of the reader / writer is well received by the card, if the card replies at that position, the positional relationship between the reception antenna of the reader / writer and the card is obtained. Is not always good.

[0006] The converse is also true. Even if the card is located at a position where the card reply wave can be received well by the receiving antenna of the reader / writer, the transmission signal of the reader / writer cannot be given to the card satisfactorily. In addition, a part of the transmission signal of the reader / writer goes around to the reception antenna of the reader / writer, and the transmission output decreases, and at the same time, a signal that goes around to a weak card response wave during reception deteriorates the reception performance.

To solve the problem, there is a method of securing a communication area by aligning the centers of the transmitting and receiving antennas of the reader / writer. However, as described above, the signal radiated from the transmitting antenna goes around to the receiving antenna. This is an unnecessary signal for reception. To eliminate this, several filters having the most attenuating characteristics at the unnecessary signal frequency are required.

Therefore, the above-described limitation of the communication area caused by the arrangement of the transmitting antenna and the receiving antenna can be solved without using a filter, and the signal radiated from the transmitting antenna goes around to the receiving antenna to improve the receiving performance. What solves the problem of deterioration is demanded.

[0009]

SUMMARY OF THE INVENTION The present invention solves the limitation of the communication area caused by the arrangement of the transmitting antenna and the receiving antenna, and the signal radiated from the transmitting antenna goes around to the receiving antenna to deteriorate the receiving performance. What is desired is a solution to the problem, which solves the limitation of the communication area caused by the arrangement of the transmitting antenna and the receiving antenna, and the signal radiated from the transmitting antenna goes around to the receiving antenna to deteriorate the receiving performance. It is an object of the present invention to provide a transmitting / receiving antenna that can solve the problem.

[0010]

A transmitting / receiving antenna according to the present invention includes a transmitting antenna constituted by a loop antenna, a receiving antenna arranged concentrically with the transmitting antenna and constituted by a loop antenna, and a receiving antenna comprising the loop antenna. And a canceling coil which is disposed on a concentric axis outside the transmitting antenna and is wound in a direction opposite to the winding direction of the receiving antenna.

A transmitting and receiving antenna according to the present invention includes a transmitting antenna constituted by a loop antenna, a receiving antenna arranged concentrically with the transmitting antenna and constituted by a loop antenna, and connected to the receiving antenna. A canceling coil which is arranged on a concentric axis outside the antenna and is wound in a direction opposite to the winding direction of the receiving antenna.

A transmitting / receiving antenna according to the present invention includes a transmitting antenna constituted by a loop antenna, and a receiving antenna arranged above or below the transmitting antenna and arranged concentrically with the transmitting antenna and constituted by a loop antenna. An antenna, a receiving antenna and a single wire rod, arranged on a concentric axis outside the transmitting antenna, and configured to include a loop antenna wound in a direction opposite to a winding direction of the receiving antenna. Consists of a coil.

A transmitting / receiving antenna according to the present invention includes a transmitting antenna constituted by a loop antenna, and a receiving antenna disposed above or below the transmitting antenna and arranged on a concentric axis of the transmitting antenna and constituted by a loop antenna. An antenna and a canceling coil connected to the receiving antenna, disposed on a concentric axis outside the transmitting antenna, and configured by a loop antenna wound in a direction opposite to a winding direction of the receiving antenna.

A transmitting and receiving antenna according to the present invention comprises a transmitting antenna formed by a loop antenna wound around a first antenna bobbin, and a second antenna disposed on a concentric axis above or below the first antenna bobbin. A receiving antenna constituted by a loop antenna wound around a bobbin; and a receiving antenna constituted by the receiving antenna and a single wire, disposed on a concentric axis outside the transmitting antenna, and wound in a direction opposite to a winding direction of the receiving antenna. And a canceling coil constituted by a loop antenna.

A transmitting / receiving antenna according to the present invention comprises a transmitting antenna constituted by a loop antenna wound around a first antenna bobbin, and a second antenna disposed on a concentric axis above or below the first antenna bobbin. A receiving antenna constituted by a loop antenna wound around a bobbin, and a loop antenna connected to the receiving antenna, disposed on a concentric axis outside the transmitting antenna, and wound in a direction opposite to a winding direction of the receiving antenna And a canceling coil constituted by:

A transmitting / receiving antenna according to the present invention comprises a transmitting antenna constituted by a loop antenna, a receiving antenna disposed concentrically with the transmitting antenna and constituted by a loop antenna, and a receiving antenna and a single wire. And a canceling coil configured by a loop antenna wound on a concentric axis outside the transmitting antenna and wound in a direction opposite to a winding direction of the receiving antenna, and connected to the canceling coil, And a canceling coil for fine adjustment constituted by a loop antenna arranged at a position overlapping a part of the transmitting antenna.

A transmitting and receiving antenna according to the present invention includes a transmitting antenna constituted by a loop antenna, a receiving antenna arranged concentrically with the transmitting antenna and constituted by a loop antenna, and a transmitting antenna connected to the receiving antenna. A canceling coil arranged on a concentric axis outside the antenna and wound in a direction opposite to the winding direction of the receiving antenna, and an end of the canceling coil to which the receiving antenna is connected And a fine-tuning canceling coil that is connected to the other end of the transmitting antenna and that is configured by a loop antenna that is arranged at a position overlapping a part of the transmitting antenna.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic configuration of a wireless card system according to the present invention.

The wireless card system includes a host device 30 such as a personal computer, a reader / writer 10, a card 2
0.

The host device 30 has a function of transmitting a control command dedicated to the reader / writer 10 to the reader / writer 10, a function of writing data to the card 20, or a function of transmitting a command and data for reading data from the card 20. Have.

The host device 30 has a function of receiving card data from the reader / writer 10.
It has a function of receiving response data dedicated to the reader / writer 10 in response to a control command dedicated to 0.

Further, the host device 30 has a function of displaying these data on a display (not shown), a function of inputting various data including commands and write data, and the like.

The reader / writer 10 has a function of receiving a command from the higher-level device 30 and executing the command in accordance with the command, and a function of responding to the higher-level device 30 in response to a command requiring a response.

The reader / writer 10 comprises a modulation / demodulation / control unit 11 composed of a digital unit and an analog unit, and an antenna unit 12 as a transmission / reception antenna. Antenna unit 1
2 includes a transmission antenna 13 and a reception antenna 15.

The digital section has a command analysis function from the host device 30, a processing function for received card data, a digital modulation function, and a digital demodulation function. The analog part is
For the card 20, a function of transmitting a power transmission wave, a function of transmitting a data signal wave, a function of receiving a card reply wave 23, a function of removing an unnecessary signal from a received signal of the card reply wave 23, a function of removing a received card reply wave Has digital conversion function.
The power transmission wave and the data signal wave form a transmission signal 14 from the antenna unit 12 to the card 20.

In the antenna section 12, the transmitting antenna 13 has a function of radiating a transmission wave of the reader / writer 10 to the space, and the receiving antenna 15 has a function of receiving a reply wave of the card 20.

In this example, the card 20 is of a batteryless type without a built-in battery.
In the case where the reader / writer 10 has antennas for transmission and reception, the contents are exactly the same. Also, the wireless tag is included in the wireless card and simply expressed as “card”.

The card 20 includes a transmitting / receiving antenna 21 and L
It consists of an SI chip 22. Transmitting / receiving antenna 21
Has a function of receiving the transmission signal 14 radiated from the reader / writer 10 and passing the reception signal to the LSI chip 22.
In addition, it has a function of emitting response data generated in the LSI chip 22 to the space (response wave 23).

In this example, the transmission / reception function is realized by one antenna, but the transmission and reception are exclusively performed by two antennas.
It is also possible to configure with a number of antennas.

The LSI chip 22 includes a transmitting / receiving antenna 21
And rectifies the signal (transmission signal 14) received at LS
A function for extracting electric power necessary for operating the I chip 22;
It has a function of demodulating a received signal and analyzing a command, a function of writing card data accordingly, or a function of reading out card data, encoding and modulating it, and supplying a signal to the transmitting / receiving antenna 21.

Here, a case where the transmitting antenna 12 of the reader / writer 10 emits a signal to the card 20 will be described.

The signal radiated to the card 20 is transmitted at the required communication distance and communication area.
Requires a high level to provide sufficient power transfer signals and data signals for the operation of.

As shown in FIG. 1, in the present invention, the card 20
In order to make the area for receiving the transmission signal 14 radiated from the transmission antenna 13 of the reader / writer 10 and the area for receiving the reply wave 23 of the card 20 by the reception antenna 15 of the reader / writer 10 similar, the transmission antenna 13 , The receiving antenna 15 is arranged on a concentric axis. Here, the case where the shape of the loop antenna constituting the transmitting antenna 13 and the loop antenna forming the receiving antenna 15 is circular is shown, but any shape such as a square or a triangle is possible.

Next, the antenna section 12 relating to the loop antenna of the present invention will be described.

FIGS. 2 and 3 show the antenna bobbin 40 of the antenna section 12. As described above, in this example, the antenna is a circular loop antenna for both transmission and reception.

As shown in the perspective view of the antenna bobbin 40 in FIG. 2, the antenna bobbin 40 is made of non-metal, and has two circular grooves 41 and 42 for winding wires constituting an antenna. The smaller radius is used for the receiving antenna 15, and the larger radius is used for the transmitting antenna 13.

That is, FIG. 3 shows a schematic configuration of the antenna bobbin 40. ΦA in the drawing of FIG.
ΦB is the diameter of the groove 42 for winding the wire rod for the receiving antenna 15, and these diameters have a relation of φA> φB.

The smaller radius is used for the transmitting antenna 13.
The larger radius may be used for the receiving antenna 15.

Next, a method for manufacturing the antenna section 12 will be described with reference to FIGS. 4, 5, 6, and 7. FIG.

First, the first method of manufacturing the antenna section 12 will be described with reference to FIGS.

FIG. 4 shows the basic production of the antenna section 12,
A transmission antenna 13 is manufactured by winding a transmission antenna wire 51 as an arbitrary wire around the groove 41 of the antenna bobbin 40, and a reception antenna wire 52 as an arbitrary wire is wound around the groove 42 of the antenna bobbin 40. To produce In this figure, the transmitting antenna 13 and the receiving antenna 1
5 are wound in the same direction, but may be wound in different directions.

The collar 40a of the antenna bobbin 40,
By providing the wire holes 61,... 66 for passing the ends of the wires 51, 52 at the portion 40b, respectively, it is possible to particularly prevent the wire from being loosened at the end of winding. The transmission antenna wire 51 is used through the wire holes 61 and 62 of the collar 40a of the antenna bobbin 40, and the reception antenna wire 52
Are holes 65 for the wire rod of the collar 40b of the antenna bobbin 40,
66 and wire hole 6 of collar 40a of antenna bobbin 40
3, 64 (as the canceling coil 53).

When a signal is radiated from the transmitting antenna 13 in this state even after the required number of windings is completed, the signal wraps around the receiving antenna 15, and a weak reply wave 23 from the card 20 is transmitted to the receiving circuit (modulation / demodulation / control unit). It is difficult to take out in 11).

Therefore, in the present invention, a part of the loop antenna constituting the receiving antenna 15 is realized by the canceling coil 53 wound close to the outside of the loop antenna constituting the transmitting antenna 13 in order to remove the wraparound component.
Note that the type of wire, the number of turns, and the inductance value are determined by the transmission / reception circuit (modem / control unit 1) of the reader / writer 10.
Since it depends on the electrical characteristics of 1), it is not specified here.

That is, the desired Q value and inductance value largely depend on the type and the number of windings of the wire, and since these desired characteristics differ depending on the reader / writer 10, they cannot be specified here.

The production of the canceling coil 53 will be described with reference to FIG. That is, the wire 52 for the receiving antenna as the winding end of the receiving antenna 15 is passed through the wire hole 63 provided in the collar 40a (corresponding to the transmitting antenna 13) of the antenna bobbin 40, and the direction opposite to the winding direction of the receiving antenna 15 is That is, the receiving antenna wire 52 is wound in the winding direction 54.

At this time, it is desirable that the transmission antenna wire 51 as the transmission antenna 13 has already been wound and the surface of the transmission antenna 13 is covered with a thin tape or the like. The wire 52 for the receiving antenna is wound so as to be superimposed thereon, and the end of the winding is formed by a wire hole 64 from the groove 41 side to the flange 4.
0a, and further, a wire rod hole 66 provided in the collar 40b.
The receiving antenna wire 52 is passed from the groove 42 side to the outside of the collar 40b.

In this case, the wire passes through the wire holes 61 provided on the flanges 40a and 40b of the antenna bobbin 40, but the end of the winding of the receiving antenna 15 is opposite to the winding direction of the receiving antenna 15 outside the transmitting antenna 13. Any method may be used as long as it is wound around the transmission antenna 13 in the direction.

The number of windings of the wire on the transmitting antenna 13 depends on the number and size of the transmitting antenna 13, the number and size of the receiving antenna 15, and the distance between the transmitting antenna 13 and the receiving antenna 15. I do.

Next, a second method of manufacturing the antenna section 12 will be described with reference to FIGS.

In this case, the transmitting antenna 13 is formed on a plane.

First, the receiving antenna 15 is manufactured by winding the receiving antenna wire 52 as an arbitrary wire around the groove 71 of the antenna bobbin 70. Here, as shown in FIG. 6, the winding direction of the receiving antenna wire 52 is in the direction of arrow a. The transmitting antenna 13 is formed on the front surface or the back surface of a non-metallic plate 72, for example, an acrylic plate or the like, and is formed of a circular loop coil (transmitting antenna wire 51). Here, the transmission antenna 13 is circular, but does not depend on the shape. The winding direction is the direction of arrow b.

Next, a canceling coil 53 for canceling a signal radiated from the transmitting antenna 13 wrapping around the receiving antenna 15 is provided on the outer periphery of the transmitting antenna 13 in the direction of the arrow b in the same direction as the winding direction of the transmitting antenna 13. Wrap around. After completion of each coil, the receiving antenna 15 is attached to the center of the transmitting antenna 13 and the canceling coil 53, and the antenna section 12 is completed as shown in FIG.

The antenna unit 12 manufactured by the above-described two manufacturing methods removes a signal radiated from the transmission antenna 13 wrapping around the reception antenna 15 and is greatly reduced as compared with the conventional case.

Next, the antenna unit 12 that completely eliminates a signal radiated from the transmitting antenna 13 wrapping around the receiving antenna 15 will be described.

The reason why the above-mentioned antenna unit 12 cannot completely eliminate the noise is because the canceling coil 53 is configured in units of circumference. If the number of turns of the canceling coil 53 is insufficient,
Although a large number of transmission signals wrap around the receiving antenna 15, if the number of turns of the canceling coil 53 is excessive, the canceling coil 53
A large number of transmission signals wrap around. It is considered that the most canceling condition is that the number of turns of the canceling coil 53 is not an integer.

Then, as a method of completely eliminating the
(1) The number of turns of the canceling coil 53 is not set to an integer value, and the winding is terminated in the middle of the final round, or (2) A canceling coil for fine adjustment is provided. Here, the latter method (2) will be described.

FIG. 8 shows a fine adjustment canceling coil 80. Here, an example of a square loop coil has been described, but the shape may be arbitrary. The winding direction is also arbitrary. One end of the fine adjustment cancellation coil 80 is connected to one end of the cancellation coil 53 (one end not connected to the reception antenna 61) as shown in FIG.

Then, by superimposing the fine adjustment canceling coil 80 on the coil of the transmitting antenna 13 and adjusting the overlapping area, it is possible to completely extinguish the transmitting signal wrapping around the receiving antenna 15.

For example, when the winding directions of the canceling coil 53 and the fine adjustment canceling coil 80 are the same, and the transmission signal wrapping around the receiving antenna 15 is larger than the signal level canceled by the canceling coil 53, In this case, the fine adjustment canceling coil 80 is largely overlapped in the inside direction of the transmission antenna 13, and in the opposite case, the cancellation coil 80 is largely overlapped in the outside direction of the transmission antenna 13. When the winding directions of the canceling coil 53 and the fine adjustment canceling coil 80 are different, the directions are opposite to each other.

Next, the measurement results will be described with reference to FIG.

The receiving antenna 15 is formed by winding a formal wire having a wire diameter of 0.3 mm around a circular antenna bobbin 70 having an inner diameter φR = 30 mm and a width of 3 mm 83 times.

The transmitting antenna 13 is formed by winding a formal wire having a wire diameter of 0.5 mm on an acrylic plate 72 with an inner diameter φT = 60 mm and 10 times in the outer circumferential direction without a gap, and a center 13 a of the transmitting antenna 13 and a receiving antenna 13. 15 center 15a
Are arranged on the same axis 73 (see FIG. 6).

Further, a canceling coil 53 is wound along the outer periphery of the transmitting antenna 13 and a formal wire having a diameter of 0.3 mm similar to that of the receiving antenna 15 is wound 11 times.
The fine adjustment offset coil 80 is also a formal wire having a wire diameter of 0.3 mm, a rectangular coil of A = 10 mm and B = 30 mm, and the number of turns is seven.

The transmission antenna 13 transmits a signal of 125 kHz from the signal generator 75 to both ends of the transmission antenna 13.
A signal waveform obtained through the receiving antenna 15, the canceling coil 53, and the fine adjustment canceling coil 80 is observed by an oscilloscope 76.

Here, the receiving antenna 71, the canceling coil 73, and the fine adjusting canceling coil 74 are formed on the back surface of the acrylic plate, and the distance between the receiving antenna 71 and these systems is 3 mm in thickness of the acrylic plate. is there.

Here, the fine adjustment coil 53 is connected as described above, and is fixed to a specific position on the coil of the transmission antenna 13 as described above.
The wraparound component of the signal radiated from the transmitting antenna 13 observed at the point (1) has completely disappeared.

Therefore, in the transmission antenna 13 and the reception antenna 15 (antenna unit 12) of the reader / writer 10 constituted by the loop antenna, the transmission antenna of the reader / writer 10 is optimized to optimize the communication area with the card 20. When the antenna 13 and the receiving antenna 15 are arranged on the concentric axis, there is a signal which is radiated from the transmitting antenna 13 and becomes unnecessary for the reception of the reader / writer 10 which wraps around the receiving antenna 15, and this phenomenon causes There is a conventional disadvantage that the transmission power of the 10 is reduced.

On the other hand, as described above, even if the transmitting antenna 13 and the receiving antenna 15 are arranged on concentric axes,
The winding end of the receiving antenna 15 is wound around the outside of the transmitting antenna 13 for canceling, and is wound in a direction opposite to the winding direction of the receiving antenna 15 or wound around the outside of the transmitting antenna 15 formed on a plane. In the direction opposite to the direction, the signal unnecessary for the reception of the reader / writer 10 which is radiated from the transmitting antenna 13 by the fine adjustment canceling coil 80 and wraps around the receiving antenna 15 is removed, and the output of the transmitting antenna 13 is removed. It is possible to secure the communication area where the level of the transmission signal 14 given to the card 20 by the reader / writer 10 becomes maximum and the level of the reply wave 23 from the card 20 received by the reader / writer 10 becomes maximum. Becomes

As described above, the limitation of the communication area caused by the arrangement of the transmitting antenna and the receiving antenna is solved.
Further, it is to solve the problem that the signal radiated from the transmitting antenna goes around to the receiving antenna to deteriorate the receiving performance.

[0072]

As described above in detail, according to the present invention, in a transmitting / receiving antenna provided with a transmitting / receiving antenna provided in a reader / writer for reading / writing a card, the transmitting / receiving antenna is provided. It is possible to provide a transmission / reception antenna that can solve the limitation of the communication area generated by the arrangement and the problem that the signal radiated from the transmission antenna goes around to the reception antenna and deteriorates the reception performance.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a wireless card system according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an antenna bobbin of an antenna unit.

FIG. 3 is a diagram showing a schematic configuration of an antenna bobbin of an antenna unit.

FIG. 4 is a diagram illustrating a method of manufacturing the antenna unit.

FIG. 5 is a diagram illustrating a method of manufacturing the antenna unit.

FIG. 6 is a diagram for explaining a method of manufacturing the antenna unit.

FIG. 7 is a diagram for explaining a method of manufacturing the antenna unit.

FIG. 8 is a diagram for explaining a fine adjustment canceling coil of the antenna unit.

FIG. 9 is a diagram for explaining connection of a fine adjustment canceling coil of the antenna unit and a measurement result of the antenna unit.

[Description of Signs] 10 ... Reader / writer 11 ... Modulation / demodulation / control unit 12 ... Antenna unit 13 ... Transmission antenna 14 ... Transmission signal 15 ... Reception antenna 20 ... Card 21 ... Transmission and reception antenna 22 ... LSI chip 23 ... Reply wave 30 ... Host device 40: Antenna bobbins 40a, 40b: Collar 41: Receiving antenna winding end 51: Transmission antenna wire 52: Receiving antenna wire 53: Canceling coil 56: Winding direction 57: Wire rod hole 58: Wire rod hole 61, ... 66 ... Wire hole

Claims (8)

[Claims] A transmitting antenna configured by a loop antenna; a receiving antenna disposed concentrically with the transmitting antenna and configured by a loop antenna; and a transmitting antenna configured by the receiving antenna and one wire. And a canceling coil disposed on a concentric axis outside the antenna and configured by a loop antenna wound in a direction opposite to a winding direction of the receiving antenna. 2. A transmitting antenna constituted by a loop antenna, a receiving antenna arranged on a concentric axis with the transmitting antenna and constituted by a loop antenna, and a concentric outside of the transmitting antenna connected to the receiving antenna. And a canceling coil, which is arranged on the axis and is formed by a loop antenna wound in a direction opposite to the winding direction of the receiving antenna. 3. A transmitting antenna constituted by a loop antenna, a receiving antenna arranged above or below the transmitting antenna, and arranged on a concentric axis of the transmitting antenna and constituted by a loop antenna. A canceling coil formed of an antenna and one wire rod, disposed on a concentric axis outside the transmitting antenna, and formed of a loop antenna wound in a direction opposite to a winding direction of the receiving antenna. A transmission / reception antenna characterized in that: 4. A transmitting antenna constituted by a loop antenna, a receiving antenna arranged above or below the transmitting antenna, and arranged on a concentric axis of the transmitting antenna and constituted by a loop antenna. A canceling coil connected to an antenna, disposed on a concentric axis outside the transmitting antenna, and configured by a loop antenna wound in a direction opposite to a winding direction of the receiving antenna. Transmitting and receiving antennas. 5. A transmitting antenna constituted by a loop antenna wound around a first antenna bobbin, and a loop wound around a second antenna bobbin arranged on a concentric axis above or below the first antenna bobbin. A receiving antenna constituted by an antenna; a loop antenna comprising the receiving antenna and one wire rod, disposed on a concentric axis outside the transmitting antenna, and wound in a direction opposite to a winding direction of the receiving antenna. A transmission / reception antenna, comprising: a canceling coil configured by: 6. A transmitting antenna constituted by a loop antenna wound around a first antenna bobbin, and a loop wound around a second antenna bobbin arranged on a concentric axis above or below the first antenna bobbin. A cancellation antenna constituted by a reception antenna constituted by an antenna, and a loop antenna connected to the reception antenna, arranged on a concentric axis outside the transmission antenna, and wound in a direction opposite to a winding direction of the reception antenna. A transmission / reception antenna, comprising: 7. A transmitting antenna constituted by a loop antenna; a receiving antenna arranged concentrically with the transmitting antenna and constituted by a loop antenna; and a transmitting antenna constituted by the receiving antenna and one wire. A canceling coil arranged on a concentric axis outside the antenna and wound in a direction opposite to a winding direction of the receiving antenna; a canceling coil connected to the canceling coil, and a part of the transmitting antenna; And a canceling coil for fine adjustment constituted by a loop antenna arranged at a position overlapping with the antenna. 8. A transmitting antenna constituted by a loop antenna, a receiving antenna arranged concentrically with the transmitting antenna and constituted by a loop antenna, and a concentric outside of the transmitting antenna connected to the receiving antenna. A canceling coil which is arranged on a shaft and is formed by a loop antenna wound in a direction opposite to the winding direction of the receiving antenna, and an end of the canceling coil opposite to an end to which the receiving antenna is connected. And a fine adjustment canceling coil that is connected to the unit and that is configured by a loop antenna that is disposed at a position overlapping a part of the transmission antenna.