Radar level gauge and waveguide transition device thereof
By using a coupling cavity structure formed by metal vias in the radar level gauge, waveguide assembly is simplified, processing costs and accuracy requirements are reduced, and performance stability is improved.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- HANGZHOU MICROIMAGE INTELLIGENT CONTROL TECHNOLOGY CO LTD
- Filing Date
- 2025-10-27
- Publication Date
- 2026-05-21
AI Technical Summary
Existing radar level gauges have complex waveguide structures that require high processing and assembly tolerances, resulting in high costs.
The coupling cavity structure, which is formed by multiple metal vias, is used to introduce signals into the coupling cavity through a microstrip antenna, which simplifies the assembly process and reduces the requirements for processing accuracy.
This simplifies the assembly process, reduces processing costs, and improves processing accuracy and performance stability.
Smart Images
Figure CN2025130126_21052026_PF_FP_ABST
Abstract
Description
Radar level gauge and its waveguide device Technical Field
[0001] This application relates to the field of level gauge equipment technology, and in particular to a radar level gauge and its waveguide device. Background Technology
[0002] A radar level gauge is a device that uses microwave technology for non-contact level measurement. It emits a radar beam, which is reflected back after encountering an object and received by the radar level gauge's receiver. The height of the material level can be calculated based on the time difference between the emitted and reflected waves. Summary of the Invention
[0003] In one embodiment of this application, a waveguide device for a radar level gauge is provided, comprising: a dielectric substrate having a first ground metal layer and a second ground metal layer respectively covering the upper and lower surfaces in the thickness direction, and a signal line located between the first ground metal layer and the second ground metal layer in the thickness direction; a coupling cavity, the coupling cavity being a dielectric cavity surrounded by a plurality of first metal vias penetrating the dielectric substrate in the thickness direction; and an antenna extending from the signal line into the coupling cavity; wherein the bottom surface of the coupling cavity is closed by the second ground metal layer, the top surface of the coupling cavity forms a perforation in the first ground metal layer, and the signal from the signal line is introduced into the coupling cavity through the antenna and transmitted through the perforation.
[0004] In one embodiment, the dielectric substrate includes a third ground metal layer, wherein the third ground metal layer and the first ground metal layer sandwich the signal line therebetween in the thickness direction, or the third ground metal layer and the second ground metal layer sandwich the signal line therebetween.
[0005] In one embodiment, the signal line and the antenna further include an impedance transformation section adjacent to the edge of the coupling cavity.
[0006] In one embodiment, the method includes: a plurality of second metal vias, each of the plurality of second metal vias penetrating the dielectric substrate in the thickness direction, the plurality of second metal vias sandwiching the signal line and the impedance transformation section in the extension direction of the dielectric substrate; wherein the edge of the signal line has a first spacing with the adjacent second metal via, and the edge of the impedance transformation section has a second spacing with the adjacent second metal via, the first spacing being different from the second spacing.
[0007] In one embodiment, the first spacing is greater than the second spacing.
[0008] In one embodiment, the coupling cavity further includes a coupling section, which is disposed on the same layer as the signal line. The signal of the signal line is introduced into the coupling cavity through the antenna and is transmitted from the cutout after being coupled through the coupling section.
[0009] In one embodiment, the coupling portion is formed in the coupling cavity and is spaced apart from the sidewall of the coupling cavity and the antenna; the coupling portion is formed in a cross shape in the extending direction of the dielectric substrate.
[0010] In one embodiment, the coupling portion is formed in the coupling cavity, the coupling portion is electrically connected to the first metal via, and is spaced apart from the antenna.
[0011] In one embodiment, the signal line is formed as a coplanar waveguide transmission line.
[0012] Another embodiment of this application provides a radar level gauge, comprising: a waveguide assembly having an input end; a waveguide conversion device as described above; and a waveguide conversion member formed in a channel shape having an input port and an output port, the input port being aligned with the cutout of the waveguide conversion device, and the output port being aligned with the input end of the waveguide assembly.
[0013] In this example, the coupling cavity 20 and the transmitting antenna are both directly formed on the dielectric substrate 10. The coupling cavity 20 is not formed through complex processes such as trenching, but rather is enclosed by multiple first metal vias 31. The antenna 40 is directly electrically connected to the signal line 13 to introduce the electrical signal from the signal line 13 into the coupling cavity 20. It is understood that the formation of the metal vias is very simple and requires no additional assembly steps. Attached Figure Description
[0014] The following figures are for illustrative purposes only and do not limit the scope of this application.
[0015] Figure 1 is a schematic diagram of the rotating waveguide device of the radar level gauge in the embodiment of this application.
[0016] Figure 2 is a plan view of the rotating waveguide device of the radar level gauge in the embodiment of this application.
[0017] Figure 3 is a schematic diagram of the impedance transformation section in the rotating waveguide device of the radar level gauge in the embodiment of this application.
[0018] Figure 4 is a schematic diagram of the radar level gauge in the embodiment of this application. Detailed Implementation
[0019] To provide a clearer understanding of the technical features, objectives, and effects of this application, specific embodiments of this application are now described with reference to the accompanying drawings, in which the same reference numerals denote the same parts.
[0020] In this document, “illustrative” means “serving as an example, illustration or description”, and any illustration or implementation described herein as “illustrative” should not be construed as a more preferred or advantageous technical solution.
[0021] To keep the drawings concise, only the parts relevant to this application are shown in each drawing, and do not represent their actual structure as a product. Furthermore, to make the drawings clear and easy to understand, in some drawings, only one of the components with the same structure or function is shown schematically, or only one is labeled.
[0022] In this article, terms such as "up," "down," "front," "back," "left," and "right" are used only to indicate the relative positional relationship between related parts, rather than to define the absolute position of these related parts.
[0023] In this article, "first," "second," etc., are used only to distinguish one another, and not to indicate degree of importance, order, or prerequisite for each other.
[0024] In this document, terms such as "equal" and "same" are not strict mathematical and / or geometric limitations, but also include errors that are understandable to those skilled in the art and permissible in manufacturing or use. Unless otherwise stated, numerical ranges in this document include not only the entire range within its two endpoints, but also several subranges contained therein.
[0025] In waveguide coupling structures used in radar level gauges, signals are mostly introduced into the substrate via an antenna, and then the waveguide structure is assembled into the groove through a slotted structure to achieve coupling. This structure requires the assembly of multiple components such as chips, antennas, substrates, slots, and insertion coupling cavities, resulting in complex manufacturing and assembly processes, complex verification, and high tolerance requirements for processing and assembly, leading to relatively higher costs. Embodiments of this application provide a radar level gauge and a waveguide-to-coupling device, which uses a coupling cavity as the connection structure to the waveguide, and then couples energy into the cavity through a microstrip antenna. This structure is simple to assemble and has low requirements for processing precision.
[0026] The exemplary embodiments will now be described more fully with reference to the accompanying drawings.
[0027] As shown in Figures 1 and 2, one embodiment of this application provides a waveguide device for a radar level gauge, comprising: a dielectric substrate 10, the dielectric substrate 10 having a first ground metal layer 11 and a second ground metal layer 12 respectively covering its upper and lower surfaces in the thickness direction, and a signal line 13 located between the first ground metal layer 11 and the second ground metal layer 12 in the thickness direction; a coupling cavity 20 formed by a dielectric cavity surrounded by a plurality of first metal vias 31 penetrating the dielectric substrate 10 in the thickness direction; and an antenna 40 extending from the signal line 13 into the coupling cavity 20. The bottom surface of the coupling cavity 20 is closed by the second ground metal layer 12, and the top surface of the coupling cavity 20 has a perforation formed in the first ground metal layer 11. The signal from the signal line 13 is introduced into the coupling cavity 20 through the antenna 40 and transmitted through the perforation.
[0028] In this example, the coupling cavity 20 and the transmitting antenna are both directly formed on the dielectric substrate 10. The coupling cavity 20 is not formed through complex processes such as trenching, but rather is enclosed by multiple first metal vias 31. The antenna 40 is directly electrically connected to the signal line 13 to introduce the electrical signal from the signal line 13 into the coupling cavity 20. It is understood that the formation of the metal vias is very simple, for example, integrally formed with the dielectric substrate 10, without requiring additional assembly steps.
[0029] The dielectric substrate 10 has a first ground metal layer 11 and a second ground metal layer 12 covering its upper and lower surfaces respectively along its thickness direction. A first metal via 31 penetrating the dielectric substrate 10 along its thickness direction is formed to have the same potential as the ground metal layer, i.e., it is equivalent to a ground layer. In other words, the first metal via 31 penetrates the first ground metal layer 11 and the second ground metal layer 12 of the dielectric substrate 10. The coupling cavity 20 is formed as a dielectric cavity, and its interior does not contain metal layers such as signal lines. The bottom surface of the coupling cavity 20 is covered by the second ground metal layer 12, the sidewalls are enclosed by the first metal via 31, and the top surface of the coupling cavity 20 is hollowed out and not covered by a metal layer. Thus, electrical signals introduced into the coupling cavity 20 are coupled through the coupling cavity 20 and emitted from the hollowed-out portion of the top surface of the coupling cavity 20.
[0030] In this example, the coupling cavity 20 and the dielectric substrate 10 are an integral structure, eliminating the need for processes such as trenching and assembly. This reduces the number of structural components and avoids assembly tolerances, thus maintaining high performance.
[0031] In some embodiments, the dielectric substrate 10 includes a third ground metal layer 14, in which the third ground metal layer 14 and the first ground metal layer 11 sandwich the signal line 13 therebetween in the thickness direction, or the third ground metal layer 14 and the second ground metal layer 12 sandwich the signal line 13 therebetween.
[0032] In this example, signal line 13 is located between the first ground metal layer 11 and the third ground metal layer 14.
[0033] The signal line 13 and the antenna 40 include an impedance transformation section 50, which is located near the edge of the coupling cavity 20.
[0034] The impedance transformation unit 50 is used for impedance matching of electrical signals. Impedance matching refers to a working state in which the load impedance and the internal impedance of the excitation source are matched to achieve maximum power output. There are two main methods of impedance matching: one is by changing the impedance (lumped-circuit matching), and the other is by adjusting the wavelength of the transmission line (transmission line matching). In practical applications, impedance matching can be achieved through series termination matching or parallel termination matching.
[0035] Specifically, the rotating waveguide device of the radar level gauge also includes: a plurality of second metal vias 32, which penetrate the dielectric substrate 10 in the thickness direction.
[0036] Multiple second metal vias 32 sandwich the signal line 13 and the impedance transformation section 50 between at least two rows of second metal vias 32 along the extension direction of the dielectric substrate 10, wherein the extension direction is, for example, the X direction shown in FIG3. The signal line 13 has a first spacing between its edge and an adjacent second metal via 32, and the impedance transformation section 50 has a second spacing between its edge and an adjacent second metal via 32; the first spacing and the second spacing are different.
[0037] In this embodiment, the signal line 13 is formed as a coplanar waveguide transmission line.
[0038] A coplanar waveguide (CPW) transmission line is a commonly used microwave planar transmission line structure, consisting of a central conductor strip and two semi-infinite ground planes (strip lines) on either side. The central conductor strip serves as the signal transmission line, while the two side strip lines act as grounding lines.
[0039] Similar to the first metal via 31, the second metal via 32 penetrates the dielectric substrate 10 in the thickness direction, with its two ends connected to the first ground metal layer 11 and the second ground metal layer 12, forming a structure with the same potential as the ground metal layer, i.e., equivalent to a ground layer. Because a large ground plane is added to both sides of the coplanar waveguide transmission line, the signal intensity radiated outward during transmission can be effectively reduced, resulting in less electromagnetic radiation and thus better anti-interference performance.
[0040] The signal line 13 is spaced apart from the second metal via 32, and the distance between the signal line 13 and the second metal via 32 is the distance between the signal line and ground. The impedance can be adjusted by adjusting the distance between the signal line and ground. Therefore, the impedance transformation unit 50 is a part of the signal line 13, and impedance transformation is achieved by changing the distance between a portion of the signal line 13 and the second metal via 32.
[0041] When the spacing between a coplanar waveguide transmission line and ground is small, the impedance is significantly affected by the spacing, especially when the spacing is less than 0.5 mm, the rate of change of the microstrip line impedance is between 20% and 50%. Coplanar waveguide transmission lines can be used in broadband power distribution circuits, which have good in-band flatness over a wide frequency range and high interference immunity.
[0042] The second metal via 32 includes multiple vias spaced apart. The diameter of the second metal via 32 can be selected to be the same as or different from that of the first metal via 31.
[0043] In one example, the first spacing is greater than the second spacing. The spacing between the impedance transformation section 50 and the second metal via 32 is less than the spacing between the signal line 13 and the second metal via 32.
[0044] In some embodiments, the coupling cavity 20 further includes a coupling part 21, which is disposed on the same layer as the signal line 13. The signal of the signal line 13 is introduced into the coupling cavity 20 through the antenna 40 and is coupled through the coupling part 21 and then emitted from the cutout of the first ground metal layer 11.
[0045] The coupling part 21 is arranged on the same layer as the antenna 40. The signal introduced into the coupling cavity 20 through the antenna 40 is coupled by the coupling part 21 and then transmitted through the output end of the coupling cavity 20—the hollow part. The coupling part 21 and the antenna 40 are arranged at intervals.
[0046] In some embodiments, the coupling portion 21 is formed in the coupling cavity 20 and is spaced apart from the sidewall of the coupling cavity 20 and the antenna 40. Exemplarily, the coupling portion 21 may be formed in a cross shape in the extending direction of the dielectric substrate 10.
[0047] As shown in Figure 4, the coupling part 21 is suspended inside the coupling cavity 20, and is spaced apart from the side wall of the coupling cavity 20. It is located at the center of the coupling cavity 20 in the signal layer where the signal line 13 is located.
[0048] In some embodiments, the coupling portion 21 is formed in the coupling cavity 20, and the coupling portion 21 is electrically connected to the first metal via 31 and is spaced apart from the antenna 40.
[0049] Another embodiment of this application provides a radar level gauge, including: a waveguide assembly having an input end; a waveguide conversion device as shown in FIG1; and a waveguide conversion member 60, the waveguide conversion member 60 being formed into a channel shape having an input port and an output port, the input port being aligned with the cutout of the waveguide conversion device, and the output port being aligned with the input end of the waveguide assembly.
[0050] The waveguide conversion component 60 is used to connect the waveguide conversion device and the waveguide assembly shown in Figure 1 for size conversion.
[0051] Typically, the cutouts in a waveguide device are circular.
[0052] In this example, the coupling cavity 20 and the transmitting antenna are both directly formed on the dielectric substrate 10. The coupling cavity 20 is not formed through complex processes such as trenching, but rather is enclosed by multiple first metal vias 31. The antenna 40 is directly electrically connected to the signal line 13 to introduce the electrical signal from the signal line 13 into the coupling cavity 20. It is understood that the formation of the metal vias is very simple and requires no additional assembly steps.
[0053] The above description is merely some embodiments of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.
Claims
1. A rotating waveguide device for a radar level gauge, comprising: A dielectric substrate (10) has a first ground metal layer (11) and a second ground metal layer (12) covering the upper and lower surfaces respectively in the thickness direction, and a signal line (13) located between the first ground metal layer (11) and the second ground metal layer (12) in the thickness direction. The coupling cavity (20) is a dielectric cavity formed by a plurality of first metal vias (31) penetrating the dielectric substrate (10) in the thickness direction; and Antenna (40), which extends from the signal line (13) into the coupling cavity (20); The bottom surface of the coupling cavity (20) is closed by the second grounding metal layer (12), and the top surface of the coupling cavity (20) has a hollowed-out section in the first grounding metal layer (11). The signal from the signal line (13) is introduced into the coupling cavity (20) through the antenna (40) and transmitted through the cutout.
2. The turnstile for a radar level gauge according to claim 1, wherein, The dielectric substrate (10) includes a third ground metal layer (14). In the thickness direction, the third ground metal layer (14) and the first ground metal layer (11) sandwich the signal line (13) therebetween, or the third ground metal layer (14) and the second ground metal layer (12) sandwich the signal line (13) therebetween.
3. The turnstile for a radar level gauge according to claim 2, wherein, The signal line (13) and the antenna (40) further include an impedance transformation section (50) adjacent to the edge of the coupling cavity (20).
4. The waveguide for a radar level gauge according to claim 3, further comprising: Multiple second metal vias (32), Each of the plurality of second metal vias (32) penetrates the dielectric substrate (10) in the thickness direction. The plurality of second metal vias (32) sandwich the signal line (13) and the impedance transformation section (50) in the middle in the extension direction of the dielectric substrate (10); The signal line (13) has a first gap between its edge and the adjacent second metal via (32), and the impedance transformation part (50) has a second gap between its edge and the adjacent second metal via (32). The first gap and the second gap are different.
5. The turnstile for a radar level gauge according to claim 4, wherein, The first spacing is greater than the second spacing.
6. The turnstile for a radar level gauge according to claim 1, wherein, The coupling cavity (20) further includes a coupling section (21). The coupling part (21) is disposed on the same layer as the signal line (13). The signal from the signal line (13) is introduced into the coupling cavity (20) through the antenna (40) and then transmitted from the cutout after being coupled through the coupling part (21).
7. The rotating waveguide device for a radar level gauge according to claim 6, wherein, The coupling part (21) is formed in the coupling cavity (20) and is spaced apart from the side wall of the coupling cavity (20) and the antenna (40); The coupling portion (21) is formed in a cross shape in the extending direction of the dielectric substrate (10).
8. The rotating waveguide device for a radar level gauge according to claim 6, wherein, The coupling portion (21) is formed in the coupling cavity (20). The coupling part (21) is electrically connected to the first metal via (31) and is spaced apart from the antenna (40).
9. The turnstile for a radar level gauge according to claim 6, wherein, The signal line (13) is formed as a coplanar waveguide transmission line.
10. A radar level gauge, wherein, include: Waveguide assembly, the waveguide assembly having an input terminal; A rotating waveguide device for a radar level gauge as described in any one of claims 1 to 9; A waveguide conversion component (60) is formed in the shape of a channel with an input port and an output port, the input port being aligned with the cutout of the waveguide conversion device, and the output port being aligned with the input end of the waveguide assembly.