Slip ring wireless transmission structure applied to X-ray tomography equipment

Abstract

The invention relates to a slip ring wireless transmission structure applied to X-ray tomography equipment, which comprises a transmitting antenna and a receiving antenna, the transmitting antenna is composed of a transmitting transmission line and a transmitting adapter plate, the transmitting antenna is arranged on the radial outer side surface of a slip ring, and the receiving antenna is fixed on an equipment rack. The structures of the matching end of the transmitting antenna, the transmitting conversion plate and the receiving antenna are optimally designed, and the microstrip line with a periodic structure is used in the transmitting transmission line, so that compared with the wireless transmission structure of the existing equipment, the near-field coupling efficiency is improved, the return loss of the system is effectively improved, the signal-to-noise ratio is reduced, and the transmission efficiency is improved. Therefore, the transmission stability and reliability are effectively improved, and the use requirements of CT equipment can be better met.

Description

Technical Field

[0001] The present invention relates to the technical field of rotary connectors, and particularly to a slip ring wireless transmission structure applied to X-ray tomography equipment. Background Art

[0002] Computed Tomography (CT) is a medical imaging technology that uses an X-ray beam to perform tomographic scans of the human body and generates detailed images of the internal structure of the body with the aid of computer processing. When a CT device is operating, the X-ray tube and the detector rotate around the patient to obtain image data at different angles. During this process, the data detected by the X-ray detector must be transmitted from the rotating part to the stationary part so that the device host can further process it to generate image data. Therefore, a large amount of data needs to be transmitted in a short time.

[0003] Most current computer X-ray tomography devices use slip rings to achieve data transmission between the rotating part and the stationary part. In a traditional conductive slip ring, the stator and the rotor are connected through brushes and slip rings respectively. Due to the relative motion characteristics between the slip ring and the stator, for low-speed control signals, etc., they can still be transmitted through the contact between the brushes and the slip ring. For high-speed data streams, the data signals on the rotating slip ring are mainly transmitted to the fixed receiving device through non-contact near-field coupling (i.e., wireless transmission).

[0004] A non-contact slip ring data transmission system generally includes a transmitting unit on the rotating part and a receiving unit on the stationary part. The transmitting unit has a transmitting antenna connected to a transmitter, which is arranged on the periphery of the rotating part of the rotating frame; the receiving unit includes a receiver and a receiving antenna connected to the receiver. During the operation of a computer X-ray tomography device, the transmitting antenna moves past the receiving antenna at a small distance, so that the signal propagated on the transmitting antenna is input to the receiving antenna through near-field coupling.

[0005] In the existing slip ring wireless transmission, the wireless transmission implementation methods of domestic and foreign manufacturers below a transmission rate of 10 Gbps are all composed of a differential transmission line (transmitting antenna) with terminal matching and a receiving differential microstrip line (receiving antenna). The differential transmission line is mainly composed of a pair of microstrip lines and a terminal matching structure. The microstrip line has a wide operating frequency band and a fast transmission speed, and has unique advantages in high-frequency applications, but it has the disadvantages of large transmission loss and large far-end crosstalk, and there are certain challenges in impedance control, crosstalk and loss, which limit the improvement of the antenna transmission performance. In addition, the existing terminal matching structure of the differential microstrip line mainly uses a coplanar waveguide structure to match with a resistor. The coplanar waveguide matching is highly sensitive to the gap size on both sides and is limited by the PCB processing technology. As the transmission rate increases, its standing wave level inevitably increases and its high-frequency performance decreases. Summary of the Invention

[0006] Aiming at the defects of the prior art, the present invention provides a slip ring wireless transmission structure applied to X-ray tomography equipment. Through structural optimization design, the echo loss of the system is improved, the anti-interference ability is enhanced, and the transmission stability and reliability are effectively improved.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is: A slip ring wireless transmission structure applied to X-ray tomography equipment, including a transmitting antenna and a receiving antenna. There are N transmitting antennas, and each transmitting antenna is composed of two transmitting transmission lines connected at the feeding end through a transmitting adapter board. The transmitting transmission lines are matched at the matching end using microstrip end matching technology. The N transmitting antennas are distributed along the circumferential direction on the outer side of the radial surface of the slip ring.

[0008] Further, each transmitting transmission line includes two parallel microstrip transmission lines, and each microstrip transmission line is provided with a differential feeding port at the feeding end.

[0009] Further, the differential feeding port is excited by a metal probe. The metal probe is connected to the circular pad in the ground layer of the microstrip transmission line, and the metal probe forms a planar coaxial structure with the annular copper avoidance area and the surrounding metal layer in the same ground layer.

[0010] Further, a matching board is provided on the back of the transmitting transmission line at the matching end, and the microstrip transmission line is transitioned to the matching board on the back through vertical interconnection technology.

[0011] Further, the matching board is a double-layer PCB structure. The upper layer of the matching board is a strip line layer, including microstrip lines and matching resistors. The lower layer of the matching board is a metal ground layer, and the metal ground layer of the matching board is connected to the metal ground layer of the microstrip transmission line.

[0012] Further, one end of the microstrip line on the matching board is connected to the matching end of the microstrip transmission line through a metal probe, the other end is connected to the matching resistor, and the other end of the matching resistor is connected to the surrounding metal ground.

[0013] Further, the characteristic impedance of the microstrip line is the same as the impedance of the matching resistor.

[0014] Further, both microstrip transmission lines of the transmitting transmission line adopt a periodic structure.

[0015] Further, the periodic structure is a periodic "T"-shaped slot distributed on the outer side of the microstrip transmission line. Among them, the horizontal slot in the "T"-shaped slot is located at the outer edge of the microstrip transmission line, making the outer edge of the microstrip transmission line present a periodic "convex" structure.

[0016] Further, the transmitting adapter board is arranged on the back of the transmitting transmission line. The transmitting adapter board is a four-layer PCB structure. The top layer of the upper PCB includes two pairs of coaxial-like structures. Each pair of coaxial-like structures is connected to two differential feeding ports of a transmitting transmission line. The bottom layer of the lower PCB includes two pairs of pads 1. The coaxial-like structures and the pads 1 are connected through metal probes, and the feeding ends of the transmitting transmission lines are transferred to the pads 1 and connectors to achieve connection.

[0017] Further, each coaxial-like structure on the top layer of the upper PCB of the transmitting adapter board consists of a circular pad, a metal probe passing through the circular pad and concentric with the circular pad, an annular copper avoidance area concentric with the pad, a metallized via outside the copper avoidance area, and a copper layer outside the copper avoidance area. The bottom layer of the upper PCB of the transmitting adapter board includes a metal probe penetrating from the top layer to the bottom layer, an annular copper avoidance area centered on the metal probe, and a metallized via on the copper layer outside the annular copper avoidance area. The metal probes on the upper PCB of the transmitting adapter board penetrate to the bottom layer of the lower PCB. The top layer of the lower PCB of the transmitting adapter board includes a metal probe, an annular copper avoidance area centered on the metal probe, and a copper layer outside the copper avoidance area. The metal probe passes through the core of the lower PCB and is connected to the pad 1 on the bottom layer of the lower PCB.

[0018] Further, the outer periphery of each pair of pads 1 on the bottom layer of the lower PCB is surrounded by metallized vias.

[0019] Further, the bottom layer of the upper PCB and the top layer of the lower PCB of the transmitting adapter board are bonded through a prepreg.

[0020] Further, the receiving antenna includes a coupled microstrip line and a pad 2. The coupled microstrip line includes two differential microstrip lines for coupling signals from the transmitting transmission line. The pad 2 is used to assemble the corresponding connector.

[0021] Further, the receiving antenna is a four-layer PCB structure. The coupled microstrip line is located on the top layer of the upper PCB. The coupled microstrip line is connected to the bottom layer of the upper PCB through a metal probe. The bottom layer of the upper PCB is a metal ground layer. The top layer of the lower PCB is a metal ground layer. The metal probe of the upper PCB penetrates the lower PCB and is connected to the pad 2 on the bottom layer.

[0022] Further, there are annular copper avoidance areas centered on the metal probes on both the bottom layer of the upper PCB and the top layer of the lower PCB of the receiving antenna.

[0023] Further, the bottom layer of the upper PCB and the top layer of the lower PCB of the receiving antenna are bonded through a prepreg.

[0024] Further, there are metallized vias around the coupled microstrip line 9 on the upper PCB board.

[0025] Beneficial effects: 1. For the slip ring wireless transmission structure of the present invention, the feeding end, matching end of the transmitting antenna, and the structure of the receiving antenna are optimized. A microstrip line with a periodic structure is used in the transmitting transmission line. Compared with the wireless transmission structure of existing devices, the near-field coupling efficiency is improved. At the same time, the system return loss is effectively improved, the signal-to-noise ratio is reduced, the transmission stability and reliability are effectively enhanced, and it can better meet the usage requirements with higher bit error rate requirements.

[0026] 2. At the matching end of the transmitting antenna of the present invention, the vertical connection technology is adopted to transition the signal on the microstrip structure. Compared with the traditional coplanar waveguide method, this matching method is less sensitive to the gap size on the matching board and mainly depends on the line width size of the microstrip line. The processing difficulty is significantly reduced, the standing wave ratio is effectively optimized, and the return loss of the antenna system is improved.

[0027] 3. The transmitting adapter board and the transmitting transmission line of the present invention are connected in a head-to-head form, and a coaxial-like structure is adopted in the vertical connection, effectively improving the matching of signal feeding, reducing signal feeding reflection, and being able to effectively suppress the distortion of the signal transmitted to the transmitting antenna, effectively improving the stability of signal transmission, and can also better match the rectangular connector.

[0028] 3. The receiving antenna of the present invention adopts a four-layer PCB structure, and its coupled signal is transmitted to the pad structure through a probe method. At the same time, a coaxial-like double-conductor structure is used to effectively suppress the distortion of the coupled signal, thereby improving the signal transmission stability and better matching its connector. Description of the drawings

[0030] Figure 1 Schematic diagram of the slip ring wireless transmission structure in the embodiment of the present invention; Figure 2 Schematic diagram of the structure of the transmitting transmission line (perspective state); Figure 3 Front view schematic diagram of the transmitting transmission line; Figure 4 Back view schematic diagram of the transmitting transmission line; Figure 5 Schematic diagram of the feeding end of the transmitting transmission line; Figure 6 Schematic diagram of the matching end of the transmitting transmission line; Figure 7 Schematic diagram of the structure of the transmitting adapter board (perspective state); Figure 8 Front view schematic diagram of the transmitting adapter board; Figure 9 Back view schematic diagram of the transmitting adapter board; Figure 10 Schematic structural diagram of the receiving antenna (perspective state); Figure 11 Front structural schematic diagram of the receiving antenna; Figure 12 Back structural schematic diagram of the receiving antenna.

[0031] Reference numerals: 1 Transmitting transmission line, 11 Microstrip transmission line, 12 "T"-shaped slot, 13 Differential feeding port, 14 Matching board, 15 Microstrip line, 16 Matching resistor; 2 Transmitting adapter board, 21 Coaxial-like structure, 22 Pad 1; 3 Receiving antenna, 31 Coupling microstrip line, 32 Pad 2, 4 Circular pad, 5 Metal ground layer, 6 Metal probe, 7 Metallized via, 8 Annular copper avoidance area. Detailed implementation manners

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] It should be noted that the structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in this technology to understand and read, and are not used to limit the implementation conditions of the present invention. Therefore, they do not have technical essential meanings. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope that can be covered by the technical content disclosed in the present invention.

[0034] The orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "middle", "longitudinal", "transverse", "horizontal", "inner", "outer", "radial", "circumferential", etc. cited in this specification is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of simplified description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0035] The slip ring wireless transmission structure of the present invention is applied in a computerized tomography device to achieve data transmission between the rotating part and the stationary part. As Figure 1 shown, the passive components of the slip ring wireless transmission mainly include three parts: a transmitting transmission line 1, a transmitting adapter board 2, and a receiving antenna 3. Among them, the transmitting transmission line 1 is used to transmit radio frequency signals, so that the radio frequency signals are transmitted on the radial side of the slip ring. The transmitting adapter board 2 is used to combine the transmitting transmission line 1 to meet the transmission requirements of different slip rings for transceiver. The transmitting transmission line 1 and the transmitting adapter board 2 form a transmitting antenna. The receiving antenna 3 is used to couple the required radio frequency signals from the transmitting transmission line 1 for recovering the required information at the backend.

[0036] Specifically, the transmitting transmission line 1 is fixed to the outer side surface of the slip ring. In the embodiment of the present invention, the number of transmitting transmission lines 1 on the outer side of each slip ring is 2N (N is an integer greater than zero). The 2N transmitting transmission lines 1 are composed of N transmitting adapter boards 2 to form N pairs, covering the entire outer side surface area of the slip ring. The specific number of transmitting transmission lines is determined by the loss of the transmission line and the diameter of the slip ring. The number of transmitting adapter boards 2 connecting the transmitting transmission lines 1 is N. Each pair of transmitting transmission lines 1 is connected by a transmitting adapter board 2 to form a transmitting antenna. The entire radial side surface of the slip ring is covered by N pairs of transmitting transmission lines 1, that is, N transmitting antennas.

[0037] The structure of the transmitting transmission line 1 is as Figures 2-3 shown. Each transmitting transmission line 1 includes two microstrip transmission lines 11 distributed in parallel to transmit differential signals. Each microstrip transmission line 11 includes a feeding end and a matching end. The microstrip transmission line 11 is provided with a differential feeding port 13 at the feeding end, as Figure 2 and 5 shown. The differential feeding port 13 is excited by a metal probe (not shown in the figure due to occlusion). The metal probe is connected to the circular pad 4 on the ground layer of the microstrip transmission line 11, forming a planar coaxial structure with the annular copper avoidance area 8 and the surrounding metal layers on the same ground layer. The feeding end of each transmitting transmission line 1 includes a total of 2 planar coaxial structures, that is, a pair of differential feeding ports 13.

[0038] In the embodiment of the present invention, in order to increase the coupling between the transmitting transmission line 1 and the receiving antenna 3 and make the transmitting transmission line 1 have a wider field distribution range in the width direction, the two microstrip transmission lines 11 of the transmitting transmission line 1 adopt a periodic structure, as Figures 2-3 shown. The periodic structure of the microstrip transmission line 11 is composed of periodic "T"-shaped slots 12 distributed at the outer edge of the microstrip transmission line 11. Among them, the horizontal slot on the "T"-shaped slot 12 is located at the outer edge of the microstrip transmission line 11 and is parallel to the length direction of the microstrip transmission line 11, so that the outer edge of the microstrip transmission line 11 presents a periodic "convex" structure.

[0039] Compared with the non-periodic structure microstrip line, the periodic structure microstrip line has a wider field distribution range, greater coupling between the transceiver, and various forms of the periodic structure microstrip line with more adjustable parameters, which is beneficial to improving performance. By appropriately adjusting the size of the specific pattern of the "T"-shaped slot 12 and the period spacing, the differential transmission coefficient between the transmitting transmission line 1 and the receiving antenna 3 can be increased by 2 - 3 dB compared with the non-periodic microstrip line structure, facilitating signal transmission.

[0040] The electromagnetic wave on the transmitting transmission line 11 propagates in the form of a traveling wave. To achieve traveling wave transmission, the ends of the two microstrip transmission lines 11 of the transmitting transmission line 1 need to be matched. For the end matching structure of the differential transmission line, the coplanar waveguide matching technology is traditionally used. Considering the actual processing level of the PCB, it is difficult to process the gaps on both sides of the coplanar waveguide strip. To improve the matching performance, in the present invention, the technology of using the microstrip end for matching is adopted. At the end of the microstrip transmission line 11, the microstrip transmission line 11 is transitioned to the matching board 14 on the back through the vertical interconnection technology with the metal probe 6.

[0041] The matching board 14 is a PCB board fixed on the back of the matching end of the microstrip transmission line 11. As Figure 4 and 6 shown, the upper layer of the matching board 14 is a stripline layer, which includes a microstrip line 15 and a matching resistor 16. The lower layer of the matching board 14 is a metal ground layer 5. The metal ground layer 5 of the matching board 14 is attached to and welded together with the metal ground layer 5 of the transmission microstrip line 15. In the matching board 14, one end of the microstrip line 15 is connected to the matching end of the microstrip transmission line 11 through the metal probe 6, and the other end is connected to the matching resistor 16. One end of the matching resistor 16 is connected to the microstrip line 15, and the other end is connected to the surrounding metal ground. The characteristic impedance of the microstrip line 15 is the same as the impedance of the matching resistor 16.

[0042] The microstrip end matching technology used in the present invention is not sensitive to the gap size compared with the traditional coplanar waveguide technology, and the processing difficulty is reduced. It mainly realizes the matching by controlling the line width size of the microstrip line 15, and can effectively optimize its voltage standing wave ratio, thereby improving the return loss of the antenna system.

[0043] The structure of the transmitting adapter board 2 is as Figures 7-9 shown. The transmitting adapter board 2 is used to connect the two transmitting transmission lines 1 in a port-to-port form at the feeding end, and transfer the two pairs of differential feeding ports 13 to the rear end for connection with the corresponding connectors. The port-to-port form means that the two transmitting transmission lines 1 are arranged in a way that the feeding ends abut against each other.

[0044] In the embodiment of the present invention, the transmitting adapter board 2 is a 4-layer (two-layer core) PCB structure. The top layer of the upper PCB is consistent with the feeding end of the transmitting transmission line 1 and is two pairs of coaxial-like structures 21. Each coaxial-like structure is composed of a circular pad 4, a metal probe 6 passing through the circular pad 4 and concentric with the circular pad 4, an annular copper avoidance area 8 concentric with the pad, metallized vias 7 circumferentially distributed outside the copper avoidance area, and a copper layer outside the copper avoidance area. The bottom layer of the upper PCB includes the metal probe 6 passing from the top layer to the bottom layer, an annular copper avoidance area 8 centered on the metal probe 6, and metallized vias 7 circumferentially distributed on the copper layer outside the annular copper avoidance area 8. The metallized vias 7 passing through the upper core board and connecting the top layer and the bottom layer of the upper PCB serve as the outer conductor of the coaxial-like structure 21 and can shield other interfering signals at the same time.

[0045] The metal probe 6 of the upper PCB of the transmitting adapter board 2 penetrates to the bottom layer of the lower PCB, that is, the metal probe 6 of the transmitting adapter board 2 directly inserts into the media of the upper and lower layers and vertically connects the wiring layers of the upper and lower PCBs; the top layer of the lower PCB of the transmitting adapter board 2 is consistent with the structure of the bottom layer of the upper PCB, including a metal probe 6, an annular copper avoidance area 8 centered on the metal probe 6, and a copper layer outside the annular copper avoidance area 8. The metal probe 6 passes through the core board of the lower PCB and is connected to the pad one 22 at the bottom layer of the lower PCB. The metal probe 6 can excite a quasi-TEM mode on the pad one 22 and perform impedance matching with the pad one 22. The pad one 22 in this embodiment is a rectangular microstrip pad. There are two pairs of pad one 22 on the bottom layer of the lower PCB, and each pair of pad one 22 is surrounded by metallized vias 7 on the outside to facilitate isolating interfering signals.

[0046] The bottom layer of the upper PCB of the transmitting adapter board 2 and the top layer of the lower PCB are bonded by a prepreg; during use, the size of the rectangular microstrip pad 22 can be adjusted by adjusting the thickness and dielectric constant of the lower PCB board to meet the requirements of different connectors.

[0047] Each transmitting adapter board 2 is connected to two transmitting transmission lines 1. There are two pairs of coaxial-like structures 21 on each transmitting adapter board 2. Each pair of coaxial-like structures 21 is connected to two differential feeding ports of one transmitting transmission line 1. The two pairs of coaxial-like structures 21 connect the two transmitting transmission lines 1 in a way that the feeding ends are adjacent to each other (i.e., port to port). The transmitting adapter board 2 and the transmitting transmission line 1 are connected in a "T" structure in cross-section. At the same time, the coaxial-like structure 21 is adopted in the vertical connection, which can effectively improve the matching of signal feeding, reduce the feeding reflection of the signal, and effectively suppress the distortion of the signal transmitted to the transmitting antenna, effectively improve the stability of signal transmission, and can also better match the rectangular connector.

[0048] Such as Figures 10-12As shown, the receiving antenna 3 couples signals from the transmitting transmission line 1 for backend processing. The receiving antenna 3 mainly includes a coupling microstrip line 31 and a pad two 32. The coupling microstrip line 31 includes two differential microstrip lines, which couple signals from the transmitting transmission line 1, and the pad two 32 is used to assemble the corresponding connector.

[0049] In an embodiment of the present invention, the receiving antenna 3 has a four-layer PCB board (two-layer board core) structure. Among them, the coupling microstrip line 31 is located on the top layer of the upper PCB, and the pad two 32 is located on the bottom layer of the lower PCB. The bottom layer of the upper PCB is a metal ground layer 5. The two differential microstrip lines are respectively connected to the bottom layer of the upper PCB through two metal probes 6, and there is an annular copper avoidance area 8 centered on the two probes on the bottom layer of the upper PCB. At the same time, in order to reduce the influence of other devices on the coupling microstrip line 31, there are metallized vias 7 around the coupling microstrip line 31 on the upper PCB board. The metal probes 6 of the upper PCB penetrate to the lower PCB. The top layer pattern of the lower PCB board is the same as the bottom layer pattern of the upper PCB board, which is the metal ground layer 5, and a copper avoidance area is arranged around the metal probes 6. The metal probes 6 pass through the lower PCB to the bottom layer of the lower PCB and are connected to the pad two 32.

[0050] In the receiving antenna 3, the bottom layer of the upper PCB and the top layer of the lower PCB are bonded by a prepreg. The receiving antenna 3 adopts a four-layer PCB board structure. The coupling microstrip line 31 of the upper PCB is connected to the pad 10 on the bottom layer of the lower PCB through two metal probes 6. The coupled signal is transmitted to the pad structure through the probe method. At the same time, using a coaxial-like double-conductor structure can effectively suppress the distortion of the coupled signal, thereby improving the signal transmission stability. At the same time, the size of the pad 10 can be adjusted by adjusting the thickness and dielectric constant of the lower PCB board to meet the requirements of different connections.

[0051] When the slip ring wireless transmission structure is in use, the transmitting adapter board 2 pairs the transmitting transmission line 1 into a transmitting antenna and covers the outer peripheral side of the slip ring. The receiving antenna 3 is fixed on the device bracket. The connector on the back of the transmitting adapter board 2 is connected to the detector on the device. When the device is running, the wireless radio frequency signal is transmitted on the radial side of the slip ring through the transmitting transmission line 1. As the slip ring rotates, the transmitting antenna passes by the receiving antenna 3, so that the signal propagating on the transmitting transmission line 1 is coupled and input into the receiving antenna 3. The radio frequency signal coupled by the receiving antenna 3 is transmitted to the computer device through the connector on the back of the receiving antenna 3 for backend processing to generate a CT image.

[0052] Compared with the existing slip ring wireless transmission devices, in the near-field coupling transmission, the field strength of this system is enhanced; through the optimized design of the matching end of the transmitting antenna, the receiving antenna, and the transmitting adapter board, the echo loss of the system is effectively improved, thereby obtaining a better signal-to-noise ratio; the transmission stability and reliability are effectively improved, better meeting the usage requirements with higher bit error rate requirements.

[0053] The above are only the preferred embodiments of the present invention, and there is no any form of limitation to the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments by using the above-disclosed technical content within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change, and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A slip ring wireless transmission structure applied to an X-ray tomography device, comprising a transmitting antenna and a receiving antenna (3), characterized in that: There are N transmitting antennas, each of which is composed of two transmitting transmission lines (1) connected at a feeding end via a transmitting adapter plate (2), and the transmitting transmission lines (1) are matched at a matching end using a microstrip end matching technology, and the N transmitting antennas can be distributed along the radial outer side of the slip ring in a circumferential direction.

2. The slip ring wireless transmission structure used in X-ray tomography equipment according to claim 1, characterized in that: Each transmitting transmission line (1) comprises two microstrip transmission lines (11) arranged in parallel, and each microstrip transmission line (11) is provided with a differential feeding port (13) at a feeding end.

3. The slip ring wireless transmission structure used in X-ray tomography equipment according to claim 2, characterized in that: The differential feeding port (13) is excited by a metal probe (6), which is connected to a circular pad (4) at the ground layer of the microstrip transmission line (11), and the metal probe (6) forms a planar coaxial structure with an annular copper avoidance area (8) at the same ground layer and a surrounding metal layer.

4. The slip ring wireless transmission structure used in X-ray tomography equipment according to claim 2, characterized in that: The transmission line (1) is provided with a matching plate (14) on the back side of the matching end, and the microstrip transmission line (11) is transitioned to the matching plate (14) on the back side through a vertical interconnection technology.

5. The slip ring wireless transmission structure used in X-ray tomography equipment according to claim 4, characterized in that: The matching board (14) is a double-layer PCB structure; the upper layer of the matching board (14) is a strip line layer, comprising a microstrip line (15) and a matching resistor (16); the lower layer of the matching board (14) is a metal ground layer (5); the metal ground layer (5) of the matching board (14) is connected to the metal ground layer (5) of the microstrip transmission line (11).

6. The slip ring wireless transmission structure used in X-ray tomography equipment according to claim 5, characterized in that: One end of a microstrip line (15) on a matching plate (14) is connected to a matching end of a microstrip transmission line (11) via a metal probe (6), and the other end is connected to a matching resistor (16), and the other end of the matching resistor (16) is connected to a surrounding metal ground.

7. The slip ring wireless transmission structure used in X-ray tomography equipment according to claim 5, characterized in that: The characteristic impedance of the microstrip line (15) is consistent with the impedance of the matching resistor (16).

8. The slip ring wireless transmission structure used in X-ray tomography equipment according to claim 2, characterized in that: Both microstrip transmission lines (11) of the transmitting transmission line (1) adopt a periodic structure.

9. The slip ring wireless transmission structure used in X-ray tomography equipment according to claim 8, characterized in that: The periodic structure is a periodic "T"-shaped slot (12) distributed outside the microstrip transmission line (11), wherein the horizontal slot in the "T"-shaped slot (12) is located at the outer edge of the microstrip transmission line (11), so that the outer edge of the microstrip transmission line (11) presents a periodic "convex" structure.

10. The slip ring wireless transmission structure used in X-ray tomography equipment according to claim 3, characterized in that: The transmitting adapter board (2) is a four-layer PCB structure, the top layer of the upper PCB includes two pairs of quasi-coaxial structures (21), each pair of quasi-coaxial structures (21) is connected to two differential feeding ports (13) of a transmitting transmission line (1), and the bottom layer of the lower PCB includes two pairs of solder pads (22), the quasi-coaxial structures (21) and the solder pads (22) are connected via metal probes (6), and the feeding end of the transmitting transmission line (1) is transferred to the solder pads (22) to achieve connection with the connector.

11. The slip ring wireless transmission structure used in X-ray tomography equipment according to claim 10, characterized in that: Each quasi-coaxial structure (21) of the top layer of the upper PCB of the transmitting adapter board (2) is composed of a circular pad (4), a metal probe (6) passing through the circular pad (4) and being concentric with the circular pad (4), an annular copper avoidance area (8) concentric with the pad, a metallized via (7) outside the copper avoidance area, and a copper layer outside the copper avoidance area. The bottom layer of the upper PCB of the transmitting adapter board (2) includes a metal probe (6) passing through from the top layer to the bottom layer, an annular copper avoidance area (8) centered on the metal probe (6), and a metallized via (7) on the copper layer outside the annular copper avoidance area (8). The metal probe (6) on the upper PCB of the transmitting adapter board (2) penetrates to the bottom layer of the lower PCB. The top layer of the lower PCB of the transmitting adapter board (2) includes a metal probe (6), an annular copper avoidance area (8) centered on the metal probe (6), and a copper layer outside the copper avoidance area. The metal probe (6) passes through the core of the lower PCB and is connected to pad 1 (22) at the bottom layer of the lower PCB.

12. The slip ring wireless transmission structure used in X-ray tomography equipment according to claim 10, characterized in that: The outer periphery of each pair of pads (22) on the bottom layer of the PCB below the transmitting adapter plate (2) is surrounded by a metallized via hole (7).

13. The slip ring wireless transmission structure used in X-ray tomography equipment according to claim 10, characterized in that: The bottom layer of the upper PCB of the transmitting adapter plate (2) and the top layer of the lower PCB are bonded together via a prepreg.

14. The slip ring wireless transmission structure used in X-ray tomography equipment according to claim 1, characterized in that: The receiving antenna (3) comprises a coupling microstrip line (31) and a second soldering pad (32); the coupling microstrip line (31) comprises two differential microstrip lines (15) and is used to couple signals from the transmitting transmission line (1); and the second soldering pad (32) is used to assemble a corresponding connector.

15. The slip ring wireless transmission structure used in X-ray tomography equipment according to claim 14, characterized in that: The receiving antenna (3) is a four-layer PCB structure, the coupling microstrip line (31) is located on the top layer of the upper PCB, the coupling microstrip line (31) is connected to the bottom layer of the upper PCB via a metal probe (6), the bottom layer of the upper PCB is a metal ground layer (5), the top layer of the lower PCB is a metal ground layer (5), and the metal probe (6) of the upper PCB penetrates the lower PCB and is connected to a second solder pad (32) of the bottom layer.

16. The slip ring wireless transmission structure used in X-ray tomography equipment according to claim 15, characterized in that: A ring-shaped copper avoidance area (8) centered on the metal probe (6) exists on both the bottom layer of the upper PCB and the top layer of the lower PCB of the receiving antenna (3).

17. The slip ring wireless transmission structure used in X-ray tomography equipment according to claim 15, characterized in that: The bottom layer of the upper PCB of the receiving antenna (3) is bonded to the top layer of the lower PCB via a prepreg.

18. The slip ring wireless transmission structure used in X-ray tomography equipment according to claim 15, characterized in that: Metallized vias (7) are provided around the coupling microstrip line (31) of the upper PCB board of the receiving antenna (3).

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