Circuit board directly connected with waveguide device

Abstract

The utility model discloses a circuit board directly connected with a waveguide device, which relates to the technical field of antennas and comprises a substrate, a feeder line and a waveguide structure. The upper end face of the substrate is provided with a switching groove, and one side wall of the switching groove is provided with a guide connection part which is used for radiating signal waves. One end of the feeder line passes through the transfer groove and is conducted with the guide connection part, so that the signal waves are fed into the guide connection part; the waveguide structure is used for connecting a waveguide device, and the waveguide structure is arranged above the transfer groove and is in coupling connection with the guide connection part so as to receive the signal wave on the guide connection part and feed the signal wave into the waveguide device; according to the utility model, the connection between the feeder line and the waveguide structure is more compact and direct, unnecessary propagation paths of signals in the substrate can be reduced, and multiple reflections and energy loss caused by complex propagation of the signals in the substrate are avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of antenna, especially a kind of circuit board of direct connection waveguide device. BACKGROUND

[0002] In the field of radar detection, waveguide antenna is widely used due to its low loss, large power capacity, compact structure, easy processing and easy debugging. Traditional automotive radar chips usually use microstrip or coplanar waveguide output interface, which largely limits the type of antenna connected thereto. Due to the compatibility and matching requirements of the interface, using a microstrip antenna is a relatively convenient and direct choice, as the microstrip antenna can be connected to the microstrip or coplanar waveguide output interface through a microstrip line to achieve signal transmission and radiation functions. However, due to the need for a medium to carry and constrain the transmission of electromagnetic waves, the characteristics of the medium material itself and its structure with the conductor strip and ground plate can cause problems such as dielectric loss, conductor loss and radiation loss, so using a microstrip antenna cannot avoid the problem of high microstrip line loss.

[0003] The current mainstream solution is a PCB-waveguide adapter structure. The currently used PCB-waveguide adapter structure mainly uses a microstrip line to convert a differential microstrip line, which is then matched with a rectangular waveguide. The microstrip part of the adapter structure has a long feed line and requires a one-to-two power divider to achieve microstrip line conversion to differential line, resulting in high loss.

[0004] Therefore, how to reduce the loss during the adapter process has become a problem to be solved in the field. SUMMARY

[0005] The main purpose of the present utility model is to provide a circuit board for directly connecting waveguide devices, which aims to reduce the loss during the adapter process.

[0006] To achieve the above-mentioned purpose, the circuit board for directly connecting waveguide devices according to the present utility model includes a substrate, a feed line and a waveguide structure. The substrate has a circuit structure engraved inside, and an adapter slot is provided on the upper end surface of the substrate. The adapter slot penetrates the substrate through one side wall arranged in the left-right direction, and the other side wall is provided with a lead-through part. The lead-through part is used to radiate signal waves. One end of the feed line penetrates the adapter slot and is in conduction with the lead-through part, and the other end is connected to the circuit structure on the substrate to feed the signal waves of the circuit structure into the lead-through part. The waveguide structure is used to connect a waveguide device. The waveguide structure is arranged above the adapter slot and is coupled to the lead-through part to receive the signal waves from the lead-through part and feed the signal waves into the waveguide device.

[0007] In an embodiment, the circuit board of the direct waveguide device further comprises a plurality of shorting members, the shorting members are arranged in the substrate along the up-down direction to ground the conducting sections, and the plurality of shorting members are arranged at the side of the transition groove to form a quarter wavelength shorted patch structure with the conducting sections.

[0008] In an embodiment, the signal wave has a wavelength of λ g , the distance between each shorting member and the transition groove is d1, the dimension of the conducting section along the left-right direction is W, and W = λ g / 4-d1.

[0009] In an embodiment, the dimension of the waveguide structure along the left-right direction is smaller than the dimension along the front-back direction.

[0010] In an embodiment, the dimension of the conducting section along the front-back direction is L, and 2W ≤ L ≤ 3.5W.

[0011] In an embodiment, the waveguide structure is a ridge waveguide, and the ridge of the ridge waveguide extends along the front-back direction.

[0012] In an embodiment, the diameter of the feed line is arranged to change along the direction close to the conducting section.

[0013] In an embodiment, the waveguide structure is provided with a clearance groove close to the end surface of the feed line to form a gap between the waveguide structure and the feed line.

[0014] In an embodiment, the circuit board of the direct waveguide device has a working center wavelength of λ0, the signal wave has a wavelength of λ g , the radial dimension of the feed line is w0, the dimension of the clearance groove along the left-right direction is w1, and w1 > w0+3×(h0 / λ g × λ0).

[0015] In an embodiment, the circuit board of the direct waveguide device has a working center wavelength of λ0, the signal wave has a wavelength of λ g , the radial dimension of the feed line is w0, the dimension of the substrate along the up-down direction is h0, the dimension of the clearance groove along the up-down direction is h1, and h1 > 3×(h0 / λ g × λ0).

[0016] The arrangement of the transition groove makes the connection between the feed line and the waveguide structure more compact and direct, reduces unnecessary propagation paths of the signal in the substrate, avoids multiple reflections and energy loss caused by complex propagation of the signal in the substrate, directly connects the feed line with the conducting section on the substrate, couples and connects the waveguide structure with the conducting section, reduces the transition, effectively controls the transition loss, and improves the system gain. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed in the embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings described below are only some of the embodiments of the present application, and not all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0018] Figure 1 The structure top view schematic diagram of the circuit board of the direct connection waveguide device according to an embodiment of the present application is provided.

[0019] Figure 2 The structure top view schematic diagram of the circuit board of the direct connection waveguide device according to an embodiment of the present application is provided. Figure 1 The structure top view schematic diagram of the circuit board of the direct connection waveguide device according to an embodiment of the present application is provided.

[0020] Figure 3 The structure top view schematic diagram of the circuit board of the direct connection waveguide device according to an embodiment of the present application is provided. Figure 1 The structure top view schematic diagram of the circuit board of the direct connection waveguide device according to an embodiment of the present application is provided.

[0021] Figure 4 The structure top view schematic diagram of the circuit board of the direct connection waveguide device according to an embodiment of the present application is provided.

[0022] Figure 5 The return loss curve and the return loss curve of the circuit board of the direct connection waveguide device according to an embodiment of the present application are provided.

[0023] BRIEF DESCRIPTION OF DRAWINGS

[0024] 100, the circuit board of the direct connection waveguide device; 1, the substrate; 11, the adapter slot; 12, the lead connection part; 2, the feeder; 21, the main feeder section; 22, the auxiliary feeder section; 3, the waveguide structure; 31, the avoiding slot; 32, the ridge; 4, the short-circuit piece.

[0025] The implementation, functional characteristics and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0027] It should be noted that if the embodiments of the utility model have directionality indication (such as up, down, left, right, front, back, etc.), the directionality indication is only used to explain the relative position relationship, movement condition, etc. between components in a certain specific posture, if the specific posture changes, the directionality indication also changes accordingly.

[0028] In addition, if the embodiments of the utility model have the description of "first", "second" and the like, the description of "first", "second" and the like is only for the purpose of description, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include at least one of the features. In addition, "and / or" or "and / or" appearing throughout the text means that the three parallel schemes are included, for example, "A and / or B" includes A scheme, or B scheme, or A and B simultaneously satisfy the scheme. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of ordinary technical personnel in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope required by the utility model.

[0029] The utility model provides a kind of circuit board 100 of direct connection waveguide device.

[0030] Please refer to Figures 1 to 3 In an embodiment of the utility model, the circuit board 100 of direct connection waveguide device includes substrate 1, feed line 2 and waveguide structure 3;Circuit structure is engraved in the inside of substrate 1, and adapter slot 11 is opened in the upper end surface of the substrate 1, the adapter slot 11 is through the substrate 1 in the side wall of left and right direction setting, another side wall is equipped with lead connection part 12, the lead connection part 12 is used to radiate signal wave;One end of feed line 2 passes through the adapter slot 11 and is conducted with the lead connection part 12, the other end is connected on the circuit structure of the substrate 1, to feed the signal wave of the circuit structure into lead connection part 12;Waveguide structure 3 is used to connect waveguide device, the waveguide structure 3 is set above the adapter slot 11 and is coupled with the lead connection part 12, to be able to receive the signal wave on the lead connection part 12 and feed the signal wave into the waveguide device.

[0031] The technical scheme of the utility model makes the connection between feed line 2 and waveguide structure 3 more compact, avoids multiple reflections and energy loss caused by complex propagation of signal in substrate 1, and connects feed line 2 directly with lead connection part 12 on substrate 1, and couples waveguide structure 3 with lead connection part 12, reduces adapter transition, effectively controls adapter loss, and improves system gain.

[0032] The material of the substrate 1 comprises at least one of hydrocarbon resin, epoxy resin, polyphenyl ether resin, polytetrafluoroethylene resin and modified materials mixed with ceramic or glass fiber.

[0033] It should be noted that the circuit board 100 of the direct connection waveguide device further comprises a waveguide feed line for connecting the waveguide structure 3 and the waveguide device.

[0034] In an embodiment of the utility model, the circuit board 100 of the direct connection waveguide device further comprises a plurality of short-circuit pieces 4, the short-circuit pieces 4 are arranged in the substrate 1 along the up-down direction and are used to ground the lead-in part 12, and the plurality of short-circuit pieces 4 are located on the side of the adapter groove 11 and are used to form a quarter wavelength short-circuit patch structure with the lead-in part 12. In this way, the size of the lead-in part 12 is reduced to close to a quarter wavelength, the overall structure size is reduced, the space utilization is improved, a stable grounding path is formed through the short-circuit pieces 4, signal interference is further reduced, the overall circuit performance is optimized, and efficient and stable signal transmission is ensured.

[0035] The short-circuit pieces 4 can be metal columns or columnar bodies made of other materials and plated with a metal layer on the surface of the columnar body to ensure good electrical conductivity. The number and position of the short-circuit pieces 4 can be adjusted according to actual needs to achieve the best signal transmission effect. By optimizing the design of the short-circuit pieces 4, signal loss can be further reduced, the overall working efficiency of the circuit board can be improved, and the demand for high-precision signal transmission can be met.

[0036] In an embodiment of the utility model, the wavelength of the signal wave is λ g , the distance between each short-circuit piece 4 and the adapter groove 11 is d1, and the size of the lead-in part 12 along the left-right direction is W, W = λ g / 4-d1. In this way, electromagnetic coupling can be accurately controlled, impedance matching can be optimized, and radiation performance can be improved, thereby improving the signal transmission and radiation efficiency of the direct connection waveguide circuit board and improving the overall performance of the system.

[0037] In an embodiment of the utility model, the size of the waveguide structure 3 along the left-right direction is smaller than the size along the front-back direction. In this way, the waveguide structure 3 is more compact in the horizontal direction, the space occupation is reduced, and at the same time, the sufficient size in the front-back direction is maintained to ensure effective transmission and radiation of signals, thereby further improving the stability and performance of the overall system.

[0038] In an embodiment of the utility model, the size of the guide connection part 12 along the front-back direction is L, 2W≤L≤3.5W. By setting like this, the ratio of L and W is accurately adjusted, the electromagnetic field distribution of the guide connection part 12 is further optimized, the signal coupling effect is enhanced, and excellent transmission performance can be maintained under different frequency bands, and the frequency band adaptability and signal stability of the system are comprehensively improved.

[0039] The input impedance of the quarter-wavelength short-circuit patch structure is usually less than 60 ohms, and the characteristic impedance of the waveguide feed line is usually greater than 120 ohms. Therefore, in an embodiment of the utility model, the waveguide structure 3 is a ridge waveguide, and the ridge of the ridge waveguide extends along the front-back direction. By setting like this, the impedance of the waveguide structure 3 is lower to achieve impedance matching, reduce signal reflection, improve transmission efficiency, and further optimize the electromagnetic field distribution of the ridge waveguide, enhance signal coupling, and ensure stable transmission performance under different frequency bands.

[0040] Specifically, the ridge waveguide can be a single-ridge waveguide, a double-ridge waveguide (see Figure 4 ), or a special-shaped ridge waveguide. The ridge waveguide can be a cuboid, a semi-cylindrical body, a ladder, or other three-dimensional structures. The appropriate form of the ridge waveguide is selected according to the actual application requirements to maximize the transmission efficiency and signal stability. The ridge width of the ridge waveguide matches the interface size of the waveguide device, ensuring seamless connection of signal transmission, reducing interface loss, further improving signal transmission efficiency, and optimizing the performance of the overall system. The ridge height of the ridge waveguide is coordinated with the thickness of the substrate 1 to enhance the electromagnetic field concentration and reduce transmission loss. Further, by optimizing the ridge structure, efficient signal transmission can be achieved, ensuring stable performance of the system under different working environments, and further improving the reliability and practicality of the overall system.

[0041] In an embodiment of the utility model, the diameter size of the feed line is arranged in a changing manner along the direction close to the guide connection part 12. The diameter of the feed line 2 gradually decreases to achieve smooth transition of impedance, reduce signal reflection, and improve transmission efficiency.

[0042] Further, the feed line 2 includes a main feed line segment 21 and an auxiliary feed line segment 22. The main feed line segment 21 has a larger diameter and is used to connect the transmitter or receiver of the circuit structure. The auxiliary feed line segment 22 has a smaller diameter and is used to connect the guide connection part 12. The main feed line segment 21 and the auxiliary feed line segment 22 combine to achieve impedance tapering, optimize the signal transmission path, reduce loss, ensure stable transmission of high-frequency signals, and improve the overall performance of the system.

[0043] It should be noted that the auxiliary feed line segment 22 can be connected by multiple rectangular structures with different lengths and widths or a single rectangular structure. By accurately designing the size of each rectangular structure, the impedance is gradually transitioned, and signal reflection and loss are further reduced.

[0044] Further, by precisely controlling the change gradient of the diameter of the feed line 2, the impedance matching is further optimized, ensuring efficient transmission of signals between the feed line and the lead-through 12, enhancing the overall performance and stability of the system.

[0045] In an embodiment of the present application, the waveguide structure 3 is provided with a clearance groove 31 at the end face close to the feed line 2, so as to form a gap between the waveguide structure 3 and the feed line 2. In this way, electromagnetic isolation between the feed line and the waveguide structure 3 is ensured, mutual interference is reduced, the purity of signal transmission is improved, and the system performance and stability are further optimized.

[0046] Further, the depth and width of the clearance groove 31 are precisely designed according to the diameter of the feed line and the size of the waveguide structure 3, so as to ensure the best electromagnetic isolation effect while avoiding excessive increase in space occupation. Through this meticulous structural optimization, the signal transmission between the feed line 2 and the waveguide is more stable, and the overall performance of the system is significantly improved.

[0047] In an embodiment of the present application, the working center wavelength of the circuit board 100 of the direct connection waveguide device is λ0, the wavelength of the signal wave is λ g , the radial dimension of the feed line 2 is w0, and the dimension of the clearance groove 31 along the left-right direction is w1, w1> w0+3×(h0 / λ g ×λ0). In this way, the size of the clearance groove 31 is precisely matched with the parameters of the feed line and the waveguide, electromagnetic interference is effectively isolated, signal transmission quality is improved, overall system performance is further optimized, and stability and reliability under different frequency bands are enhanced.

[0048] In an embodiment of the present application, the working center wavelength of the circuit board 100 of the direct connection waveguide device is λ0, the wavelength of the signal wave is λ g , the radial dimension of the feed line is w0, the dimension of the substrate 1 along the up-down direction is h0, and the dimension of the clearance groove 31 along the up-down direction is h1, h1>3×(h0 / λ g ×λ0). In this way, the height of the clearance groove 31 is precisely matched with the parameters of the substrate 1 and the waveguide, electromagnetic interference in the up-down direction is effectively isolated, signal transmission stability is further improved, system performance under different frequency bands is optimized, and overall reliability and practicability are enhanced.

[0049] In an embodiment of the present application, the working frequency band of the circuit board 100 of the direct connection waveguide device is 76GHz-79GHz, the substrate 1 is made of PPO resin + glass fiber modified material with a dielectric constant of 3.1, the thickness h0 of the up-down direction is 0.127mm, and the waveguide structure 3 is made of metal copper material.

[0050] The main feeder segment 21 has a diameter w0=0.29mm, and the auxiliary feeder segment 22 has a single-section rectangular matching, a diameter of 0.13mm, and a wire length of 0.61mm; the avoidance groove 31 has a size h1=1mm along the up-down direction and a size w1=0.5mm along the left-right direction.

[0051] The distance d1 between the center of the shorting member 4 and the edge (transition groove 11) of the guide 12 is 0.18mm, the guide 12 has a size L=1.13mm along the front-rear direction, and a size W=0.39mm along the left-right direction.

[0052] The narrow side of the waveguide feeder is 0.85mm, the wide side of the waveguide feeder is 2.8mm, the waveguide structure 3 has a cuboid structure in a single-ridge form, has a size 1.3mm along the front-rear direction, a size 0.38mm along the left-right direction, and a size 0.755mm along the up-down direction.

[0053] Please refer to Figure 5 , Figure 5 For the insertion loss curve and the return loss curve of the PCB-waveguide transition structure, it can be seen that the loss insertion loss of the 76GHz-79GHz frequency band is less than 1.2dB, the feeder loss is excluded about 0.38dB, and the loss of the circuit board 100 directly connected with the waveguide device is about 0.82dB; in addition, the return loss of the 76GHz-79GHz is less than-29dB.

[0054] The above description is only an exemplary embodiment of the present application, and does not limit the patent range of the present application, and any equivalent structural transformation, direct / indirect application in other related technical fields, or the like, which is made by using the content of the present application specification and drawings, is included in the patent protection range of the present application.

Claims

1. A circuit board for a direct connect waveguide device, the circuit board comprising: The application relates to a substrate with a circuit structure inside and a transition slot on the upper end surface of the substrate, wherein the transition slot penetrates the substrate through a side wall arranged in the left-right direction, and the other side wall is provided with a lead-through part for radiating signal waves; a feed line is arranged, one end of which penetrates the transition slot and is in conduction with the lead-through part, and the other end is connected with the circuit structure on the substrate, so as to feed the signal waves of the circuit structure into the lead-through part; and a waveguide structure is arranged, which is used for connecting a waveguide device, and is arranged above the transition slot and is coupled with the lead-through part, so as to receive the signal waves on the lead-through part and feed the signal waves into the waveguide device. The circuit board of the direct-connection waveguide device further comprises a plurality of short-circuiting pieces arranged in the substrate along the up-down direction, which are used for grounding the lead-through part, and the plurality of short-circuiting pieces are arranged on the side of the transition slot, which are used for forming a quarter-wavelength short-circuiting patch structure with the lead-through part. The waveguide structure has a size in the left-right direction smaller than a size in the front-rear direction. The size of the lead-through part in the front-rear direction is L, and 2W<=L<=3.5W.

2. The direct connected waveguide device circuit board of claim 1, wherein, The waveguide structure is a ridge waveguide, and the ridge of the ridge waveguide extends in the front-rear direction.

3. The direct connected waveguide device circuit board of claim 2, wherein, The wavelength of the signal wave is λ g The distance between each shorting member and the transition slot is d1, and the dimension of the transition portion in the left-right direction is W, W = λ g / 4 - d1.

4. The direct connected waveguide device circuit board of claim 3, wherein, The diameter size of the feed line is arranged in a changing mode along the direction close to the lead-through part.

5. The direct connected waveguide device circuit board of claim 3, wherein, The waveguide structure is provided with a avoiding slot on the end surface close to the feed line, so as to form a gap between the waveguide structure and the feed line.

6. The direct connected waveguide device circuit board of claim 5, wherein, ​ 7. The direct connected waveguide device circuit board of claim 1, wherein, ​ 8. The direct connected waveguide device circuit board of claim 1, wherein, ​ 9. The direct connected waveguide device circuit board of claim 8, wherein, The working center wavelength of the circuit board of the direct connection waveguide device is λ0, the wavelength of the signal wave is λ g , the radial dimension of the feeder is w0, the dimension of the avoidance slot along the left-right direction is w1, w1> w0+3×(h0 / λ g ×λ0).

10. The direct connected waveguide device circuit board of claim 8, wherein, The working center wavelength of the circuit board of the direct connection waveguide device is λ0, the wavelength of the signal wave is λ g , the radial dimension of the feeder is w0, the dimension of the substrate along the up-down direction is h0, the dimension of the avoiding slot along the up-down direction is h1, and h1>3×(h0 / λ g ×λ0).

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