JP2014168520A - Radio communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio communication device capable of transmitting data at a high speed, allowing reliable transmission/reception of radio waves within a close distance between a rotary unit and a fixed unit.SOLUTION: A radio communication device allows communication between a first unit and a second unit which relatively turn. Annular first and second leakage transmission paths which radiate radio waves in a preset angle direction from the transmission path along which multiple slots are formed are attached to first and second units respectively, leaving a certain interval between the paths. The first leakage transmission path has an annular shape around the rotation center in a first turn direction and the second leakage transmission path has an annular shape around the rotation center in a second turn direction. The diameters of the first and second leakage paths are the same and the slot faces are opposed to each other. A transmitter is connected to one end of the first leakage transmission path and a receiver is connected to one end of the second leakage transmission path.

Description

  Embodiments described herein relate generally to a wireless communication apparatus that performs wireless communication between a fixed unit and a rotating unit using a leakage cable.

  Conventionally, as a wireless communication apparatus between a fixed unit and a rotating unit, for example, an X-ray CT (Computed tomography) apparatus can be cited. In an X-ray CT apparatus, an X-ray tube and an X-ray detector are disposed opposite to a rotating unit in a gantry, and X-rays are exposed while rotating the X-ray tube and the X-ray detector around the subject. X-rays transmitted through the specimen and attenuated are detected, and an X-ray CT image such as a tomographic image is generated based on the X-ray detection data.

  In the X-ray CT apparatus, X-ray detection data is transmitted from the rotary unit to the fixed unit in a non-contact manner. Patent Document 1 discloses a transmission and reception device using optical communication as a non-contact data transmission device. In optical communication, communication is performed by providing a light emitting element on the rotating unit side and a light receiving element on the fixed unit side.

  However, there is a point inadequate for reliably transmitting and receiving data at a short distance and performing high-speed data transmission.

Japanese Patent No. 3476469

  The problem to be solved by the invention is to provide a wireless communication apparatus capable of transmitting and receiving radio waves reliably at a short distance between a rotating unit and a fixed unit and capable of high-speed data transmission.

  The wireless communication apparatus according to the embodiment is a wireless communication apparatus that performs communication between a first unit and a second unit that rotate relative to each other about an axis of rotation, and is connected to a transmission path from one end to a terminator. A plurality of slots are formed along the transmission line, and radio waves are radiated from the transmission path in a predetermined angular direction. The plurality of slots are directed to the second unit side, and the rotation center is the first turn direction. A first leaky transmission line that is formed in an annular shape and attached to the first unit, and reaches the terminator from one end so as to receive radio waves from the same angle direction as the radio wave radiation direction of the first leaky transmission path. A plurality of slots are formed along the transmission path, the plurality of slots are directed toward the first unit, and have an annular shape in a second direction opposite to the first turn direction around the rotation center. Having the same diameter as the diameter of the first leaky transmission line, A second leaky transmission line attached to the second unit opposite to the one leaky transmission line at a certain interval; a transmitter connected to the one end of the first leaky transmission line; And a receiver including a receiver connected to the one end of the two leaky transmission paths.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which shows schematically the X-ray CT apparatus which is an application example of the radio | wireless communication apparatus which concerns on one Embodiment. The perspective view which shows an example of the leakage cable used for the radio | wireless communication apparatus of one Embodiment. 1 is a configuration diagram illustrating a wireless communication apparatus according to an embodiment. Explanatory drawing which shows arrangement | positioning of the leakage cable in one Embodiment. Explanatory drawing which shows the radiation angle of the leakage cable in one Embodiment. Explanatory drawing which shows the radiation direction and coupling degree when making two leaky cables in one embodiment forward. Explanatory drawing which shows a radiation direction and coupling | bonding degree when an endfire type and a backfire type leaky cable are used in one Embodiment. Explanatory drawing which shows the coupling degree when making the leakage cable in one embodiment into reverse and forward rotation. Explanatory drawing which shows the leaking cable which arranged the slot surface facing in one Embodiment. Explanatory drawing which shows the leaking cable which arrange | positioned the slot surface non-opposing. Explanatory drawing which shows the coupling degree of the leakage cable in the case where a slot surface is facing, and the case where it is not facing. Explanatory drawing which shows the example which made the leakage cable and the planar antenna oppose. Explanatory drawing which shows the directivity of a leaking cable. Explanatory drawing which shows arrangement | positioning of the leakage cable in the modification of one Embodiment. Explanatory drawing which shows arrangement | positioning of the leakage cable of the radio | wireless communication apparatus which concerns on 2nd Embodiment. Explanatory drawing of the phase adjustment by the coaxial cable in 2nd Embodiment.

  Embodiments for carrying out the invention will be described below with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected about the same location.

(First embodiment)
FIG. 1 is an explanatory diagram schematically illustrating a configuration of an X-ray CT apparatus which is an example of a device to which the wireless communication apparatus according to the embodiment is applied. In FIG. 1, an X-ray CT apparatus 100 has a gantry 10 composed of a rotation unit 11 and a fixed unit 12. The rotation unit 11 is a ring that is driven to rotate, and an X-ray tube 12 and an X-ray detector 13 are disposed to face each other. The central portion of the rotation unit 11 is open, and the subject P placed on the couch top 17 is inserted into the opening.

  The X-ray tube 13 exposes X-rays to the subject P placed in the effective visual field region. The X-ray detector 14 detects X-rays transmitted through the subject P. For example, a plurality of detection elements configured by combining scintillators and photodiodes are two-dimensionally arranged.

  The rotation of the rotating unit 11 causes the X-ray tube 13 and the X-ray detector 14 to face each other while rotating about the body axis of the subject P. If the top plate 17 is moved along the opposite axis direction of the subject P simultaneously with this rotation, so-called helical scanning that scans the subject in a spiral shape becomes possible.

  The data acquisition unit 15 is called DAS (Data Acquisition System), converts a signal output from the X-ray detector 14 for each channel into a voltage signal, amplifies it, and further converts it into a digital signal. This digital signal is sent to a console unit (not shown) constituting the computer system via the non-contact type data transmission device 16, and tomographic image information of the subject is obtained by performing image processing on the digital data. can do.

  In the present embodiment, a wireless communication device using a leakage cable is used as the non-contact data transmission device 16 between the rotating unit 11 and the fixed unit 12. Hereinafter, a specific configuration of a wireless communication apparatus that performs communication between the rotary unit 11 and the fixed unit 12 will be described.

 FIG. 2 is a perspective view illustrating an example of a transmission path of a leakage cable used in the wireless communication apparatus according to the first embodiment. In FIG. 2, the leakage cable 20 constituting the leakage transmission path has a center conductor 21 covered with an insulator 22 and an outer conductor 23 on the outer periphery of the insulator 22. The outer conductor 23 is periodically provided with perforations called slots 24 at regular intervals P to transmit and receive radio waves from the slots 24.

 FIG. 3 is a configuration diagram showing a wireless communication apparatus according to an embodiment, and shows an example adopted in an X-ray CT apparatus. FIG. 3A is a side view, and FIG. 3B is a front view.

 As shown in FIG. 1, the X-ray CT apparatus 100 mainly includes a gantry 10 having an X-ray tube 13 and an X-ray detector 14 that emit X-rays, a top plate 17 (bed), and a console for operation. Is done. In the gantry 10, a bearing 18 for the rotation unit 11 is fixed to the fixed unit 12, and the rotation unit 11 is held by the bearing 18. In the rotation unit 11, an X-ray tube 13 that emits X-rays and an X-ray detector 14 are installed at positions facing the X-ray tube 13. The data is transmitted to the fixed unit 12 side by the non-contact data transmission device 16 via the data collection unit 15 (FIG. 1) detected by the X-ray detector 14.

  Hereinafter, a wireless communication device that implements the non-contact data transmission device 16 will be described in detail.

 The wireless communication apparatus 200 according to the first embodiment includes leakage cables 201 and 202 bent in an annular shape, and the leakage cable 201 bent in an annular shape is attached to the rotary unit 11 and the leakage cable bent in an annular shape. 202 is attached to the fixture 19 of the fixing unit 12, and the leakage cables 201 and 202 are arranged to face each other at a distance D close to each other. Leakage cables 201 and 202 function as antennas. One of the rotating unit 11 or the fixed unit 12 constitutes a first unit to which the leakage cable 201 is attached, and the other of the rotating unit 11 or the fixed unit 12 constitutes a second unit to which the leakage cable 202 is attached, The first unit and the second unit rotate relative to the rotation center X as an axis.

 A transmitter 301 is connected to the leakage cable 201. Detection data from the X-ray detector 14 is supplied to the transmitter 301 via the data collection unit 15 and the LAN cable. Hereinafter, in order to make the explanation easy to understand, the X-ray detector 14 is illustrated as being connected to the transmitter 301. The transmitter 301 and the leakage cable 201 are connected by a coaxial cable. Further, the leakage cable 202 on the fixed unit 12 side is connected to the receiver 302, and the receiver 302 is connected to the image processing unit 40. Leakage cable 202 and receiver 302 are connected by a coaxial cable, and receiver 302 and image processing unit 40 are connected by a LAN cable. The transmitter 301 and the receiver 302 constitute a wireless device.

 The bending radii of the leakage cables 201 and 202 are, for example, 10 times or more the outer diameter of the leakage cables. This is to prevent the slots 241 and 242 of the leaky cables 201 and 202 from being crushed and the characteristics as specified cannot be obtained. Leakage cables 201 and 202 are bent in an annular shape so as to have the same diameter, and are installed so that the center of the ring coincides with the rotation center X of the rotation unit 11. That is, even if the rotation unit 11 rotates, the positional relationship in which the leakage cables 201 and 202 installed in the rotation unit 11 and the fixed unit 12 face each other is always maintained.

 In addition, the leakage cables 201 and 202 are installed at positions where the surfaces of the slots 241 and 242 face each other and are separated by a certain distance D. The reason why the slots 241 and 242 face each other will be described later.

 FIG. 4 is an explanatory diagram showing the arrangement of the leakage cables 201 and 202 in the wireless communication apparatus according to the embodiment. As shown in FIG. 4A, the leakage cables 201 and 202 have feeding ends 251 and 252 at one end of the transmission line, respectively, and termination resistors 261 and 262 as termination units at the other end of the transmission line. doing. The power supply terminal 251 to which the transmitter 301 is connected and the terminating resistor 261 form a first leaky transmission line, and the terminal resistor 262 to the power supply terminal 252 to which the receiver 302 is connected to the second leaky transmission line. Configure.

 As shown in FIG. 4A, the first leakage transmission path by the leakage cable 201 is formed in an annular shape, and rotates clockwise (turn direction A) from the feeding end 251 toward the terminating resistor 261 with the rotation center X as an axis. ) Is bent. The second leakage transmission path formed by the leakage cable 202 has an annular shape and is bent counterclockwise (turn direction B) from the feeding end 252 toward the terminating resistor 262 with the rotation center X as an axis. That is, the turn direction A and the turn direction B are reversed.

 FIG. 4B is an explanatory diagram showing the opposing arrangement of the leakage cables 201 and 202, and for convenience of explanation, the leakage cables 201 and 202 are shown in a straight line for the sake of convenience. Leakage cables 201 and 202 are installed such that the surfaces of slots 241 and 242 face each other and are separated by a fixed distance D.

  Next, details of the leakage cable 20 used in the wireless communication apparatus 200 will be described. FIG. 5 is a diagram for explaining the radiation angle of the leakage cable 20. The leakage cable 20 has a power supply side 25 at one end and a termination resistor 26 as a terminator at the other end. For convenience, the leakage cable 20 is shown extending straight.

 As shown in FIG. 5A, the radiation angle θ from the transmission line of the leakage cable 20 is defined as an angle with respect to the direction Y perpendicular to the longitudinal direction from the power supply end 25 connecting the transmitter 30 toward the terminal resistor 26. The In general, a case where radio waves are radiated from the power supply end 25 toward the termination resistor 26 is called an endfire type, and the radiation angle is expressed by a positive angle (θ). On the other hand, a case where radio waves are radiated from the terminating resistor 26 toward the power supply end 25 is referred to as a backfire type, and the radiation angle is expressed by a negative angle (−θ).

 As shown in FIG. 5B, the radiated radio wave is radiated at an angle θ not only in the direction of the slot 23 but also in all directions along the transmission path of the leakage cable 20.

 Further, as shown in FIG. 5C, when receiving radio waves at a position away from the leaky cable 20 by a certain distance D, if the radiation angle θ is large, the propagation distance L in the space becomes long. Increased and reception level decreased. In addition, since radio waves are radiated along the transmission path of the leaky cable 20, it is difficult to receive radio waves with the leaky cable 20 arranged oppositely.

 Therefore, the radiation angle θ is preferably close to 0 °, and preferably within about ± 45 ° at the maximum. In FIG. 5C, when the propagation distance at the radiation angle θ1 is L1, the propagation distance at the radiation angle θ2 (θ1 <θ2) is represented by L2 (L1 <L2).

  4A, the turn direction A from the feeding end 251 to the termination resistor 261 of the leakage cable 201 and the turn direction B from the feeding end 252 to the termination resistor 262 of the leakage cable 202 are reversed as described above. It is installed to be.

 Here, the radiation direction when the leakage cable 201 and the leakage cable 202 are reversed and forward rotation and the degree of coupling at that time will be described. It is assumed that the leaky cables 201 and 202 are cables having the same radiation angle characteristics. In FIG. 4B, since the turn direction A and the turn direction B are opposite to each other, the radiation directions of the leakage cable 201 and the leakage cable 202 are the same. Therefore, the second leaky transmission path can receive radio waves from the same angle direction as the radio wave radiation direction of the first leaky transmission path, and the radio waves can be transmitted and received most efficiently.

 On the other hand, FIG. 6 shows the radiation direction and the degree of coupling at that time when the turn directions of the leak cable 201 and the leak cable 202 are both bent in the same direction, that is, when the turn direction is forward. In FIG. 6, it can be seen that it is difficult to receive radio waves because the radiation directions from the leakage cable 201 and the leakage cable 202 do not match.

 Further, FIG. 7 shows that the leakage cable 201 is an endfire type in which radio waves are radiated from the power supply end 25 toward the termination resistor 26, and the leakage cable 202 is back in which radio waves are radiated from the termination resistance 26 toward the power supply end 25. The radiation direction and the degree of coupling at that time are shown for the fire type. In FIG. 7, since the radiation directions of the leaky cable 201 and the leaky cable 202 coincide with each other, radio waves can be transmitted and received most efficiently. However, it is necessary to prepare two different types of leakage cables 201 and 202.

 FIG. 8 assumes that a TranferJet is used as a wireless device including the transmitter 301 and the receiver 302, and in the case where the distance D between the leakage cables 201 and 202 is 10 cm in the band of 4000 MHz to 5000 MHz. The measurement result of the electric power transmitted to the termination resistance of the leakage cable 202 when the power is supplied to 201 is shown (TranferJet is a proximity wireless communication system).

 FIG. 8 shows the degree of coupling when the leaking cables 201 and 202 are installed so as to be opposite to each other (thick solid line) and when the leaking cables 201 and 202 are installed so as to be forward (dotted line). ing. As can be seen from FIG. 8, it can be seen that the leakage cables 201 and 202 are installed so as to be reversely rotated, and the loss is about 20 to 30 dB less than the case where they are installed so as to be rotated in the forward direction.

 In the first embodiment, it is assumed that the leakage cables 201 and 202 having the same radiation angle characteristics are used. However, the absolute values of the radiation angles are equal and the radiation directions are those of the endfire and the backfire. Even if the installation is performed in the forward direction (FIG. 7) or the radiation angle is different, it may be possible to efficiently transmit and receive radio waves by tilting the installation surface.

  Next, the reason for installing the leaking cables 201 and 202 so that the surfaces of the slots 241 and 242 face each other will be described. FIG. 9 shows a state where the surface of the slot 241 of the leakage cable 201 and the surface of the slot 242 of the leakage cable 202 face each other. FIG. 10 shows an example in which the surface of the slot 241 of the leakage cable 201 and the surface of the slot 242 of the leakage cable 202 are not opposed to each other.

 FIG. 11 shows the degree of coupling between the case where the slot faces are opposite and the case where the slot faces are not. FIG. 11 shows the measurement result of the power supplied to the power supply end 251 of the leaky cable 201 and transmitted to the termination resistor 262 of the leaky cable 202 when the distance D between the leaky cables 201 and 202 is 10 cm.

 The thick solid line in FIG. 11 indicates the degree of coupling when the slot surfaces are opposed to each other, and the dotted line indicates the degree of coupling when the slot surfaces are not opposed. As can be seen from FIG. 11, when the slot surfaces are made to face each other, the reception level becomes higher by about 10 dB than when the slot surfaces are not made to face each other. In general, as shown in FIG. 5 (b), radio waves are radiated in all directions along the transmission path of the leakage cable 20, so that when the distance D between the leakage cables 201 and 202 is long, the slot surface is A reception level that is not much different between the case of facing and the case of non-facing is obtained. However, when the distance D of the leakage cable cannot be made long as in the case of an X-ray CT apparatus in which a communication device needs to be housed in the gantry 10, radio waves can be reliably transmitted and received by facing the slot surface. Can do.

  Next, the reason for making the leakage cables 201 and 202 face each other at a constant distance D will be described.

 FIG. 12 is an example in which the leakage cable 201 and the planar antenna 50 are opposed to each other. FIG. 12 shows that when a radio wave is radiated from the leakage cable 201, only a part of the radio wave can be received in the radio wave reception area 51 of the planar antenna 50. FIG. 13 is a diagram illustrating the directivity of the leakage cable 201. FIG. 13 shows that the endfire type in which radio waves are radiated in the direction from the feeding end 251 to the terminating resistor 261 is a very narrow directional antenna with a radiation angle of 13 degrees and a half-value width of 5 degrees. .

 When leaking cables 201 and 202 are opposed to each other, as shown in FIG. 4B, all the transmitted radio waves can be received, so that radio waves can be received more effectively than using a high gain antenna with a small opening area. And a high reception level can be obtained. In addition, since the radiation angle of the radio wave can be surely adjusted by facing each other, stable radio wave reception can be performed.

  Next, a modified example of the wireless communication apparatus 200 according to the embodiment, that is, an example in which the lengths of the opposing leakage cables 201 and 202 are changed will be described. In the wireless communication apparatus 200 of FIG. 4, the example has been described in which the leakage cables 201 and 202 have the same length. When the leakage cables 201 and 202 have the same length, the transmission radio wave can be received effectively. On the other hand, if the leakage cable is long, it may be restricted during installation.

 FIG. 14 is an explanatory diagram when the lengths of the leakage cables 201 and 202 are different. As shown in FIG. 14A, the leakage cables 201 and 202 have power feeding ends 251 and 252 and termination resistors 261 and 262, respectively, and the length of the leakage cable 202 is shorter than the leakage cable 201. The first leakage transmission path formed by the leakage cable 201 has an annular shape and is bent clockwise (turn direction A) from the feeding end 251 toward the terminating resistor 261 with the rotation center X as an axis. The second leakage transmission path formed by the leakage cable 202 has an annular shape and is bent counterclockwise (turn direction B) from the feeding end 252 toward the terminating resistor 262 with the rotation center X as an axis.

 FIG. 14B is a diagram for explaining the arrangement of the leakage cables 201 and 202. For convenience, the leakage cables 201 and 202 are shown in a straight line. Leakage cables 201 and 202 are installed such that the surfaces of slots 241 and 242 face each other and are separated by a certain distance D.

 Since the length of the leakage cable 202 is short, only a part of the radio wave transmitted from the leakage cable 201 can be received. As the cable length of the leaky cable increases, the antenna gain increases. Therefore, in order to obtain a higher reception level, the length of the leaky cable is preferably long and the length of each leaky cable is preferably the same. However, if the required wireless communication speed can be obtained, the degree of freedom in installation can be increased by shortening the length of the leakage cable.

 Next, a radio apparatus including the transmitter 301 and the receiver 302 will be described. For example, a transmission speed of at least 280 Mbps is required for transmission of image data of an X-ray CT apparatus. TransferJet is useful as a technology that satisfies the requirements for high-speed wireless communication at short distances. However, the transmitters 301 and 302 in the embodiment are not specified by TransferJet, and need to be appropriately selected depending on the required communication speed and the distance D of the leaked cable.

  In the first embodiment described above, the leakage cables 201 and 202 bent in an annular shape are arranged opposite to each other at a fixed distance D on both the rotating unit 11 and the fixed unit 12 so that the turn directions are opposite to each other, and radiation is performed. By aligning the directions, radio waves can be reliably transmitted and received, and high-speed data transmission is possible.

(Second Embodiment)
Next, a wireless communication apparatus according to the second embodiment will be described. The difference from the first embodiment is that one of the leakage cables installed in the rotary unit 11 or the fixed unit 12 is short, and a plurality of (for example, two) leakage cables are connected via a coaxial cable. This is the point.

 FIG. 15 is an explanatory diagram illustrating a wireless communication device 200 according to the second embodiment. In FIG. 15A, one leakage cable 201 is installed on the rotating unit 11 side as in FIG. 4, and two leakage cables 202 and 203 shorter than the leakage cable 201 are installed on the fixed unit 12 side. Is installed.

 The leaky cable 201 has a power supply end 251 at one end of the transmission line, and a termination resistor 261 that is a terminator at the other end of the transmission line. The power supply end 251 to which the transmitter 301 is connected and the terminating resistor 261 constitute a first leaky transmission line. The short leakage cables 202 and 203 have power supply ends 252 and 253 and termination resistors 262 and 263, respectively. The coaxial cable 27 connects between the termination resistor 262 of the leakage cable 202 and the power supply end 253 of the leakage cable 203. Yes. The leakage cable 203, the coaxial cable 27, and the leakage cable 203 from the terminating resistor 263 to the feeding end 252 to which the receiver 302 is connected constitute a second leakage transmission path.

 As shown in FIG. 15A, the first leakage transmission path by the leakage cable 201 has an annular shape and rotates clockwise (turn direction A) from the feeding end 251 toward the terminating resistor 261 with the rotation center X as an axis. ) Is bent. The second leakage transmission path including the leakage cables 202 and 203 has an annular shape and is bent counterclockwise (turn direction B) from the feeding end 252 toward the terminating resistor 263 with the rotation center X as an axis. .

 FIG. 15B is a diagram for explaining the opposing arrangement of the leaky cable 201 and the leaky cables 202 and 203. For convenience, the leaky cables 201, 202, and 203 are shown in a straight line. The leakage cable 201 and the leakage cables 202 and 203 are installed so that the surfaces of the slot 241 and the slots 242 and 243 face each other and are separated by a certain distance D. The length of the coaxial cable 27 is adjusted so that the phases on the terminal end side 262 of the leaky cable 202 and the power supply end side 253 of the leaky cable 203 coincide.

 The reason for adjusting the phase will be described with reference to FIG. FIG. 16A shows a case where the phase 28 of the radio wave incident on the leaky cable 203 matches the phase 29 of the radio wave incident on the leaky cable 202. Since the phases match, the receiver 302 can receive radio waves stably without interference between radio waves incident on the leaky cable 202 and the leaky cable 203. λg1 indicates the wavelength of radio waves of the leaking cables 202 and 203, and λg2 indicates the wavelength of radio waves of the coaxial cable 27.

 On the other hand, FIG. 16B shows a case where the phase 28 of the radio wave incident on the leaky cable 203 and the phase 29 of the radio wave incident on the leaky cable 202 are different. If the phase 28 and the phase 29 are different, the radio waves incident on the leaking cables 202 and 203 interfere with each other and affect the strength of the radio wave level, so-called fading is caused. If there is interference, the level received by the receiver 302 varies, which causes the communication speed to vary.

 Therefore, it is important to adjust the phase with the coaxial cable 27 so that the phases of radio waves incident on the leaky cable 202 and the leaky cable 203 coincide. In the example of FIG. 16, the length of the coaxial cable 27 is adjusted to adjust the phase. However, the phase adjustment method is not limited to this, and adjustment using a phase shifter may be used.

 In a device such as the X-ray CT apparatus 100, various devices are attached to the fixed unit 11 and the rotating unit 12. Therefore, it may be difficult to arrange the leakage cables 201 and 202 having the same length as shown in FIG. In addition, as described in the example of FIG. 14, there is a method of shortening one leakage cable 202, but the reception level is lowered, and a necessary communication speed may not be obtained.

 When the installation form as shown in FIG. 16 is adopted, the degree of freedom of installation of the leakage cables 202 and 203 can be increased, and the lengths of the first leakage transmission path and the second leakage transmission path can be made equal. As in FIG. 4B, it is possible to efficiently transmit and receive radio waves.

  In the example of FIG. 16, the configuration in which a plurality of short cables are connected to one of the fixed unit 11 side and the rotating unit 12 side has been described. However, a plurality of short cables are connected to both the fixed unit 11 side and the rotating unit 12 side. You may make it do.

  In the second embodiment described above, by connecting a plurality of short leakage cables with coaxial cables, the degree of freedom of installation in equipment can be increased, and radio waves equivalent to one leakage cable can be transmitted and received. High-speed data transmission is possible.

  In addition, although several embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the invention described in the claims and equivalents thereof as well as included in the scope and gist of the invention.

DESCRIPTION OF SYMBOLS 100 ... X-ray CT apparatus 200 ... Wireless communication apparatus 11 ... Rotary unit 12 ... Fixed unit 16 ... Non-contact data transmission device 18 ... Bearing for rotary unit 19 ... Fixture 20, 201, 202, 203 ... Leakage cable (leakage transmission path) )
DESCRIPTION OF SYMBOLS 21 ... Center conductor 22 ... Insulator 23 ... Outer conductor 24, 241, 242, 243 ... Slot 251, 252, 253 ... Feed end 261, 262, 263 ... Terminating resistor 27 ... Coaxial cable 301 ... Transmitter 302 ... Receiver

Claims (5)

A wireless communication device that performs communication between a first unit and a second unit that rotate relative to each other about a rotation center,
A plurality of slots are formed along a transmission path from one end to the terminator, and radio waves are radiated from the transmission path in a predetermined angle direction, the plurality of slots are directed to the second unit side, and the rotation center A first leakage transmission path that is attached to the first unit in a ring shape in the first turn direction around the axis;
A plurality of slots are formed along a transmission path from one end to a terminator so as to receive radio waves from the same angle direction as the radio wave radiation direction of the first leaky transmission path, and the plurality of slots are the first slots. Facing the unit side, having an annular shape in the second turn direction opposite to the first turn direction around the rotation center, and having the same diameter as the diameter of the first leaky transmission line, A second leaky transmission line attached to the second unit so as to face the leaky transmission line at a certain interval;
A radio including a transmitter connected to the one end of the first leaky transmission line and a receiver connected to the one end of the second leaky transmission line;
A wireless communication device comprising:   The wireless communication apparatus according to claim 1, wherein the first leaky transmission line and the second leaky transmission line have substantially the same length.   The wireless communication apparatus according to claim 1, wherein a length of the second leaky transmission path is shorter than a length of the first leaky transmission path.   At least one of the first leaky transmission line and the second leaky transmission line is constituted by a plurality of leaky cables and a coaxial cable connecting the respective leaky cables in series, and a connection part of the plural leaky cables The wireless communication apparatus according to claim 1, wherein the phases are set to be substantially equal.   The radius of the first leaky transmission line and the second leaky transmission line forming an annular shape is 10 times or more of the outer shape of the leaky cable constituting the first leaky transmission line and the second leaky transmission line transmission line. The wireless communication apparatus according to claim 1.

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