A radar level meter and its waveguide conversion device

Abstract

The present application relates to a waveguide transfer device for a radar level meter, comprising: a dielectric substrate, the dielectric substrate having a first grounding metal layer and a second grounding metal layer covering a first surface and a second surface in a thickness direction, and a signal line located between the first grounding metal layer and the second grounding metal layer in the thickness direction; a coupling cavity, the coupling cavity being formed as a dielectric cavity surrounded by a plurality of first metal vias penetrating the dielectric substrate in the thickness direction; and an antenna, the antenna extending from the signal line into the coupling cavity; wherein the bottom surface of the coupling cavity is closed by the second grounding metal layer, and the top surface forms a hollow in the first grounding metal layer, and the signal of the signal line is introduced into the coupling cavity through the antenna and emitted through the hollow.

Description

Technical Field

[0001] The present application relates to the technical field of level meter equipment, and in particular to a radar level meter and a waveguide conversion device thereof. Background Art

[0002] Radar level meter is a device that uses microwave technology to measure non-contact level. It transmits a radar beam, which is reflected back after encountering an object and received by the receiver of the radar level meter. The height of the level can be calculated based on the time difference between the transmitted wave and the reflected wave.

[0003] In the existing waveguide coupling structure for radar level meters, the signal is mostly introduced into the substrate through the antenna, and then the waveguide structure is combined into the groove through the groove structure to achieve coupling. This structure requires the assembly of multiple structures such as the substrate, antenna, substrate, groove, and plug-in coupling cavity. The process and assembly are complex, the verification is complex, and there are large tolerance requirements for processing and assembly, which is relatively more expensive. Summary of the invention

[0004] The embodiments of the present application provide a radar level meter and a waveguide conversion device thereof, which use a coupling cavity as a connection structure with a waveguide and couple energy into the cavity in the form of a microstrip antenna. The structure is simple to assemble and requires low processing accuracy.

[0005] In one embodiment of the present application, a waveguide transfer device for a radar level meter is provided, comprising:

[0006] a dielectric substrate having a first grounding metal layer and a second grounding metal layer covering a first surface and a second surface in a thickness direction, and a signal line located between the first grounding metal layer and the second grounding metal layer in the thickness direction;

[0007] A coupling cavity, wherein the coupling cavity is formed as a dielectric cavity surrounded by a plurality of first metal vias penetrating the dielectric substrate in a thickness direction; and

[0008] An antenna, the antenna extending from the signal line into the coupling cavity;

[0009] The bottom surface of the coupling cavity is closed by the second grounding metal layer, and the top surface is hollowed out in the first grounding metal layer. The signal of the signal line is introduced into the coupling cavity through the antenna and emitted through the hollowing out.

[0010] In one embodiment, the dielectric substrate includes a third grounding metal layer, and in a thickness direction, the third grounding metal layer and the first grounding metal layer or the second grounding metal layer sandwich the signal line therebetween.

[0011] In one embodiment, an impedance transformation portion is further included between the signal line and the antenna, and the impedance transformation portion is adjacent to an edge of the coupling cavity.

[0012] In one embodiment, the present invention comprises: a plurality of second metal vias, wherein the second metal vias penetrate the dielectric substrate in a thickness direction,

[0013] The plurality of second metal vias sandwich the signal line and the impedance transformation portion in the extension direction of the dielectric substrate;

[0014] There is a first distance between the edge of the signal line and the adjacent second metal via, there is a second distance between the edge of the impedance transformation portion and the adjacent second metal via, and the first distance is different from the second distance.

[0015] In one embodiment, the first spacing is greater than the second spacing.

[0016] In one embodiment, the coupling cavity further comprises:

[0017] A coupling part is arranged at the same layer as the signal line, and the signal of the signal line is introduced into the coupling cavity through the antenna, and is emitted from the hollow cavity after being coupled by the coupling part.

[0018] In one embodiment, the coupling portion is formed in the coupling cavity and is spaced apart from the side wall of the coupling cavity and the antenna;

[0019] The coupling portion is formed in a cross shape in an extending direction of the dielectric substrate.

[0020] 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.

[0021] In one embodiment, the signal line is formed as a coplanar waveguide transmission line.

[0022] Another embodiment of the present application further provides a radar level meter, comprising:

[0023] a waveguide assembly having an input end;

[0024] A waveguide device as described above;

[0025] A waveguide conversion component is formed into a channel shape with an input port and an output port, wherein the input port is aligned with the hollow of the waveguide conversion device, and the output port is aligned with the input end of the waveguide component.

[0026] In this example, the coupling cavity 20 and the transmitting antenna are all directly formed on the dielectric substrate 10, wherein the coupling cavity 20 is not formed by a complex process such as trenching, but is surrounded by a plurality of first metal vias 31. The antenna 40 is directly electrically connected to the signal line 13 to introduce the electrical signal of the signal line 13 into the coupling cavity 20. It can be understood that the formation method of the metal via is very simple and does not require the introduction of additional assembly steps. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The following drawings are only used to illustrate and explain the present application, and do not limit the scope of the present application:

[0028] Figure 1 It is a structural schematic diagram of the waveguide transfer device of the radar level meter in the embodiment of the present application;

[0029] Figure 2 It is a schematic plan view of a waveguide transfer device of a radar level meter in an embodiment of the present application.

[0030] Figure 3 It is a schematic structural diagram of the impedance transformation part in the waveguide conversion device of the radar level meter in the embodiment of the present application.

[0031] Figure 4 Schematic diagram of the structure of the radar level meter in the embodiment of the present application. DETAILED DESCRIPTION

[0032] In order to have a clearer understanding of the technical features, purposes and effects of the invention, the specific embodiments of the invention are now described with reference to the accompanying drawings, in which the same reference numerals represent the same parts.

[0033] In this document, “exemplary” means “serving as an example, instance or illustration”, and any diagram or implementation described in this document as “exemplary” should not be interpreted as a more preferred or more advantageous technical solution.

[0034] In order to simplify the drawings, only the parts related to the present invention are schematically shown in each figure, and do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically drawn or marked.

[0035] In this document, “upper”, “lower”, “front”, “back”, “left”, “right”, etc. are only used to indicate the relative position relationship between related parts, rather than to limit the absolute positions of these related parts.

[0036] In this article, "first", "second", etc. are only used to distinguish each other, and do not indicate the importance and order, or the premise of each other's existence.

[0037] In this article, "equal", "same" and the like are not strictly limited in the mathematical and / or geometric sense, but also include errors that can be understood by those skilled in the art and are allowed in manufacturing or use. Unless otherwise specified, the numerical ranges herein include not only the entire range within its two endpoints, but also several sub-ranges contained therein.

[0038] Example embodiments will now be described more fully with reference to the accompanying drawings.

[0039] like Figure 1 to Figure 2 As shown, one embodiment of the present application provides a waveguide transfer device for a radar level meter, comprising:

[0040] A dielectric substrate 10, the dielectric substrate 10 having a first grounding metal layer 11 and a second grounding metal layer 12 covering a first surface and a second surface in a thickness direction, and a signal line 13 located between the first grounding metal layer 11 and the second grounding metal layer 12 in the thickness direction;

[0041] A coupling cavity 20, which is formed as a dielectric cavity surrounded by a plurality of first metal vias 31 penetrating the dielectric substrate 10 in the thickness direction; and

[0042] Antenna 40, the antenna 40 extends from the signal line 13 into the coupling cavity 20;

[0043] The bottom surface of the coupling cavity 20 is closed by the second grounding metal layer 12, and the top surface is hollowed out in the first grounding metal layer 11. The signal of the signal line 13 is introduced into the coupling cavity 20 through the antenna 40 and transmitted through the hollowing.

[0044] In this example, the coupling cavity 20 and the transmitting antenna are all directly formed on the dielectric substrate 10, wherein the coupling cavity 20 is not formed by a complex process such as trenching, but is surrounded by a plurality of first metal vias 31. The antenna 40 is directly electrically connected to the signal line 13 to introduce the electrical signal of the signal line 13 into the coupling cavity 20. It can be understood that the formation method of the metal via is very simple and does not require the introduction of additional assembly steps.

[0045] The dielectric substrate 10 has a first grounding metal layer 11 and a second grounding metal layer 12 covering the first surface and the second surface in the thickness direction, and the first metal via 31 penetrating the dielectric substrate 10 in the thickness direction is formed into a structure with the same potential as the grounding metal layer, that is, equivalent to the grounding layer. The coupling cavity 20 is formed as a dielectric cavity, and there is no metal layer such as a signal line inside. The bottom surface of the coupling cavity 20 is covered by the second grounding metal layer 12, the side wall is surrounded by the first metal via 31, and the top surface is hollowed out without a metal layer covering, so that the electrical signal introduced into the coupling cavity 20 is emitted from the hollow part of the top surface after being coupled by the coupling cavity 20.

[0046] In this example, the coupling cavity 20 and the dielectric substrate 10 are an integrated structure, and no processes such as trenching and assembly are required, which reduces structural parts and avoids assembly tolerance, thereby maintaining high performance.

[0047] Furthermore, the dielectric substrate 10 includes a third grounding metal layer 14 , and in the thickness direction, the third grounding metal layer 14 and the first grounding metal layer 11 or the second grounding metal layer 12 sandwich the signal line 13 therebetween.

[0048] In this example, the signal line 13 is located between the first ground metal layer 11 and the third ground metal layer 14 .

[0049] An impedance transformation portion 50 is further included between the signal line 13 and the antenna 40 , and the impedance transformation portion 50 is adjacent to the edge of the coupling cavity 20 .

[0050] The impedance transformation unit 50 is used for impedance matching of the electrical signal. Impedance matching refers to a working state in which the load impedance and the internal impedance of the excitation source are adapted to each other 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 by series terminal matching or parallel terminal matching.

[0051] Specifically, it includes: a plurality of second metal vias 32 , and the second metal vias 32 penetrate the dielectric substrate 10 in the thickness direction.

[0052] The plurality of second metal vias 32 sandwich the signal line 13 and the impedance transformation portion 50 in the extending direction of the dielectric substrate 10;

[0053] There is a first spacing between the edge of the signal line 13 and the adjacent second metal via 32 , and there is a second spacing between the edge of the impedance transformation portion 50 and the adjacent second metal via 32 , and the first spacing is different from the second spacing.

[0054] In the present embodiment, the signal line 13 is formed as a coplanar waveguide transmission line.

[0055] Coplanar waveguide (CPW) is a commonly used microwave planar transmission line structure. It consists of a central conductor strip and semi-infinite ground planes on both sides. The central conductor strip serves as the signal transmission line, and the strips on both sides serve as ground lines.

[0056] Similar to the first metal via 31, the second metal via 32 penetrates the dielectric substrate 10 in the thickness direction, and its two ends are connected to the first grounding metal layer 11 and the second grounding metal layer 12 to form a structure with the same potential as the grounding metal layer, that is, equivalent to the grounding layer. Since a large area of ​​grounding plane is added on both sides of the coplanar waveguide transmission line, the signal strength radiated outward during transmission can be effectively reduced, and the electromagnetic radiation generated is small, so it has good anti-interference performance.

[0057] 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 the ground. The impedance can be adjusted by adjusting the distance between the signal line and the ground. Therefore, the impedance transformation part 50 is a part of the signal line 13, and the impedance transformation is achieved by changing the distance between the local part of the signal line 13 and the second metal via 32.

[0058] When the distance between the coplanar waveguide transmission line and the ground is small, the impedance is greatly affected by the distance, especially when the distance is less than 0.5mm, the impedance of the microstrip line changes between 20% and 50%. Coplanar waveguide transmission lines can be used in broadband power distribution circuits, which require good in-band flatness within a wide frequency band and high anti-interference performance.

[0059] The second metal vias 32 include a plurality of holes, which are arranged at intervals. The diameter of the second metal vias 32 can be selected to be the same as or different from that of the first metal vias 31 .

[0060] In a specific example, the first spacing is greater than the second spacing. The spacing between the impedance transformation portion 50 and the second metal via 32 is smaller than the spacing between the signal line 13 and the second metal via 32 .

[0061] Furthermore, the coupling cavity 20 further comprises:

[0062] The coupling part 21 is arranged at 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 emitted from the hollow cavity after being coupled by the coupling part 21 .

[0063] The coupling part 21 and the antenna 40 are arranged at the same layer. 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, that is, the hollow part. The coupling part 21 and the antenna 40 are arranged at intervals.

[0064] Optionally, the coupling portion 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;

[0065] The coupling portion 21 is formed in a cross shape in the extending direction of the dielectric substrate 10 .

[0066] like Figure 3As shown, the coupling portion 21 is suspended in the coupling cavity 20 , is spaced apart from the side wall of the coupling cavity 20 , and is disposed at the center of the coupling cavity 20 in the signal layer where the signal line 13 is located.

[0067] Optionally, 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 .

[0068] Another embodiment of the present application further provides a radar level meter, comprising:

[0069] a waveguide assembly, the waveguide assembly having an input end;

[0070] like Figure 1 The transfer waveguide device shown;

[0071] The waveguide conversion component 60 is formed into a channel shape with an input port and an output port. The input port is aligned with the hollow of the waveguide conversion device, and the output port is aligned with the input end of the waveguide component.

[0072] The waveguide conversion member 60 is used to connect Figure 1 The transfer waveguide device shown is used for size conversion between the waveguide components.

[0073] Typically, the hollowing out in the waveguide device is formed in a circular shape.

[0074] In this example, the coupling cavity 20 and the transmitting antenna are all directly formed on the dielectric substrate 10, wherein the coupling cavity 20 is not formed by a complex process such as trenching, but is surrounded by a plurality of first metal vias 31. The antenna 40 is directly electrically connected to the signal line 13 to introduce the electrical signal of the signal line 13 into the coupling cavity 20. It can be understood that the formation method of the metal via is very simple and does not require the introduction of additional assembly steps.

[0075] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A waveguide transfer device for a radar level meter, characterized in that: include: A dielectric substrate (10), the dielectric substrate (10) comprising a first grounding metal layer (11) and a second grounding metal layer (12) covering a first surface and a second surface in a thickness direction, and a signal line (13) located between the first grounding metal layer (11) and the second grounding metal layer (12) in the thickness direction; A coupling cavity (20), the coupling cavity (20) being formed as a dielectric cavity enclosed by a plurality of first metal vias (31) penetrating the dielectric substrate (10) in a thickness direction; and An antenna (40), the 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 grounding metal layer (12), and the top surface is hollowed out in the first grounding metal layer (11); the signal of the signal line (13) is introduced into the coupling cavity (20) through the antenna (40) and is emitted through the hollowing out; The dielectric substrate (10) comprises a third grounding metal layer (14), and in the thickness direction, the third grounding metal layer (14) and the first grounding metal layer (11) or the second grounding metal layer (12) sandwich the signal line (13) therebetween; An impedance transformation portion (50) is further included between the signal line (13) and the antenna (40), and the impedance transformation portion (50) is adjacent to an edge of the coupling cavity (20); comprising: a plurality of second metal vias (32), wherein the second metal vias (32) penetrate the dielectric substrate (10) in the thickness direction, The plurality of second metal vias (32) sandwich the signal line (13) and the impedance transformation portion (50) in the extension direction of the dielectric substrate (10); There is a first spacing between the edge of the signal line (13) and the adjacent second metal via (32), and there is a second spacing between the edge of the impedance transformation portion (50) and the adjacent second metal via (32), and the first spacing is different from the second spacing.

2. The waveguide transfer device for a radar level meter according to claim 1, characterized in that: The first interval is greater than the second interval.

3. The waveguide transfer device for a radar level meter according to claim 1, characterized in that: The coupling cavity (20) further comprises: A coupling portion (21), wherein the coupling portion (21) and the signal line (13) are arranged in the same layer, and the signal of the signal line (13) is introduced into the coupling cavity (20) through the antenna (40), and is emitted from the hollow cavity after being coupled by the coupling portion (21).

4. The waveguide transfer device for a radar level meter according to claim 3, characterized in that: The coupling portion (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).

5. The waveguide transfer device for a radar level meter according to claim 3, characterized in that: The coupling portion (21) is formed in the coupling cavity (20); the coupling portion (21) is electrically connected to the first metal via (31) and is spaced apart from the antenna (40).

6. The waveguide transfer device for a radar level meter according to claim 2, characterized in that: The signal line (13) is formed as a coplanar waveguide transmission line.

7. A radar level meter, characterized in that: include: a waveguide assembly having an input end; The waveguide transfer device for a radar level meter according to any one of claims 1 to 6; A waveguide conversion component (60) is formed into a channel shape having an input port and an output port, the input port is aligned with the hollow of the waveguide conversion device, and the output port is aligned with the input end of the waveguide component.

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