Component for a high-frequency field device, high-frequency field device and measuring location

Abstract

The invention relates to an assembly comprising: a coaxial plug connector (21) comprising an inner conductor (22), a surrounding outer conductor (23), a base (24) having an end face (25) and a plurality of spacers (26), and a printed circuit board (11) having an electrically isolated conductor path (12) and a conductor structure (13), a plurality of connection surfaces (14, 15) and shielding elements (32); wherein the inner conductor (22) and the conductor path (12) are electrically connected, the outer conductor (23) and the conductor structure (13) are electrically connected, and the base (24) is integrally bonded to the outer conductor (23); each spacer (26) protrudes from the end face (25) and is molded onto the base (24). The coaxial plug connector (21) is arranged on the printed circuit board (11), each spacer (26) is integrally bonded to a first joining location (14), and a gap (31) is formed between the end face (25) of the base (24) and the printed circuit board (11). Each shielding element (32) is positioned with a space between two adjacent spacers (26) and is integrally bonded to the base (24) and one of the second connection surfaces (15).

Description

Technical Field

[0001] This invention relates to an assembly having a coaxial connector arranged on a printed circuit board and transmitting high-frequency electromagnetic signals from a conductor to a conductor path. The invention also relates to high-frequency field devices and measurement locations that include the aforementioned components and are configured to record various measured variables by means of suitable sensors. Background Technology

[0002] High-frequency field devices are used in process and automation technologies, particularly for detecting fill levels and / or determining the dielectric properties of media. For this purpose, the applicant has manufactured and distributed a large number of different types of field devices. An example of a field device for determining dielectric properties by means of electromagnetic signals in the microwave range is known from DE102017130728A1, which discloses a field device that determines the dielectric value of a medium by measuring the phase shift of an electromagnetic signal generated when electromagnetic waves of different frequencies propagate through the medium. Furthermore, a field device for measuring dielectric values, known from DE102020134320A1, measures the dielectric constant of a fluid guided in a pipe, wherein changes in the amplitude and phase of a microwave signal that has passed through the container and is closely related to the dielectric value of the medium are measured. Examples of field devices for determining fill levels are known from DE102012104858A1 and DE102013108490A1, which disclose a field device that determines the distance to the surface of the medium or to another radar target in the pipe by generating a frequency-modulated radar signal that is reflected at the surface of the medium and then received again. Characteristics such as the distance to the surface of the medium are determined from the characteristics of the received signal. Furthermore, a fill level measuring device known from DE102020134061A1 measures the fill level of a container by transmitting a radar signal in a high-frequency range and receiving the radar signal reflected by the fill material according to the transition time principle. The radar signal has a frequency between 0.03 GHz and 300 GHz, where typical frequency bands for this type of measurement are 2 GHz, 26 GHz, 79 GHz, or 120 GHz. All the aforementioned types of high-frequency field devices are based on the principle that the signal to be transmitted is generated by measuring electronics, conducted to a transmitting antenna and radiated there, and the measured signal is received by a receiving antenna. The signals to be transmitted and the measurement signals are conducted via a coaxial conductor between the antenna device and the corresponding electronic components.

[0003] In this process, the coaxial conductor is connected to the corresponding electronic components via a coaxial connector. A potential problem arises where high-frequency interference signals may appear laterally at the transition between the inner conductor and the conductor path of the coaxial connector. These interference signals can then interfere with the electronic components of the device, thus affecting measurements. In particular, if the amplitude of the measured signal is comparable to the amplitude of the interference signal, these interference signals may render the measurement of material properties impossible.

[0004] US2003052755A1 addresses this issue by disclosing a coaxial connector with an electromagnetic shielding sleeve having an annular mounting surface that can be integrally bonded to a printed circuit board by means of full-surface adhesive or solder joint, thereby preventing the occurrence of interference signals. The prior art is associated with the following problems: during connection to the printed circuit board, air is trapped inside the annular structure, which contains holes for the inner conductor. This air expands and contracts during solder joint formation, thereby impairing the overall bond and, particularly, creating a risk of short circuits between the inner and outer conductors due to flowing solder. Summary of the Invention

[0005] The present invention is based on the objective of providing a component that, on the one hand, reduces interference signals that occur laterally from the interface between the inner conductor and the conductor path of a coaxial connector, and on the other hand, allows for undamaged solder joints, wherein the risk of short circuits between the inner and outer conductors of the coaxial connector is reduced.

[0006] This invention achieves this objective by means of a component according to independent claim 1.

[0007] The components according to the invention include: a coaxial connector having an inner conductor, an outer conductor surrounding the inner conductor, and a base having an end face and a plurality of spacers; and a printed circuit board having a conductor path and a conductor structure having a plurality of first connection surfaces, a plurality of second connection surfaces, and a plurality of shielding elements; wherein the conductor path and the conductor structure are electrically isolated; wherein the inner conductor is electrically connected to the conductor path; wherein the outer conductor is electrically connected to the conductor structure; wherein the base is integrally coupled to or integrally formed on the outer conductor; wherein each of the plurality of spacers is integrally formed on the base and protrudes from the end face; wherein the coaxial connector is configured to connect to the coaxial conductor and is arranged on the printed circuit board; wherein each of the spacers is integrally coupled to a first engagement position of the conductor structure, particularly by means of solder; wherein a gap is formed between the end face of the base and the printed circuit board; wherein the shielding elements are positioned in each case to have space between two adjacent spacers and are integrally coupled to the base and each of the second connection surfaces.

[0008] In one embodiment of the invention, the end face of the base has a generally polygonal shape having at least three corners; wherein a plurality of spacers have one spacer at each corner of the polygon.

[0009] In one embodiment of the invention, the polygon is a rectangle, particularly a square.

[0010] In one embodiment of the invention, spaced-apart shielding elements are attached between each pair of adjacent spacers; wherein the distances from the shielding elements to the corresponding two adjacent spacers are substantially equal.

[0011] In one embodiment of the invention, the shielding element has a size of 100 micrometers or larger in a direction parallel to the printed circuit board.

[0012] The component device according to the invention comprises two components according to the invention, wherein the two bases of the two coaxial connectors are spaced less than 1 cm apart.

[0013] According to the field device of the present invention, the field device is used to determine the measured variable of a medium, particularly the fill level or dielectric properties, including one or more components or component devices according to at least one of the preceding claims.

[0014] One embodiment of the field device includes electronics connected to the component and configured to generate, in particular, an electrical transmit signal at a carrier frequency between 0.03 GHz and 300 GHz, and to determine defined characteristic variables based on the received signal.

[0015] One embodiment of the field device includes: one or more antennas for transmitting and / or receiving high-frequency electromagnetic signals; one or more coaxial conductors for conducting the transmitted signal to one of the one or more antennas, and for conducting a received signal received by one of the one or more antennas to one of the components connected to the electronics.

[0016] The measurement location according to the invention includes a field device according to the invention and a container for containing a medium, wherein the field device is arranged on or attached to the container and connected to an antenna via a coaxial conductor, and wherein the measured variable to be determined is the filling level of the medium.

[0017] The field device according to the invention includes: a container for containing a medium, particularly a conduit for guiding the medium; wherein electronic devices are arranged on or attached to the container; wherein the electronic devices are connected to two antennas via two coaxial conductors; wherein the measured variable to be determined is the dielectric properties of the medium or one or more measured variables that can be derived from the medium; wherein the signal frequency is at least 0.1 GHz and less than 40 GHz, particularly less than 20 GHz.

[0018] The advantages of this invention are that commercially available coaxial connectors with a base and spacers integrally formed thereon can be used. In these coaxial connectors, the spacers have a square coverage area with a side length approximately 25% to 35% of the side length of the square base. These coaxial connectors with spacers allow for the use of solder joints in a manufacturing process without damage to the solder structure and / or the occurrence of short circuits. The amplitude of any interference signals can then be reduced multiple times by attaching a shielding element, which can be cost-effectively manufactured from a solder preform. Another advantage is that a standard placement process can be performed with high manufacturing precision during printed circuit board assembly, wherein solder paste is first applied to the printed circuit board, then the solder preform is placed by machine, and subsequently the coaxial connector is placed. During subsequent reflow soldering of the printed circuit board, the solder preform melts and integrally bonds to the coaxial connector and the printed circuit board. Furthermore, it is advantageous that assembly requires very little additional space. Attached Figure Description

[0019] The invention will be explained in more detail with reference to the following figures.

[0020] In the picture: Figure 1a An embodiment of a printed circuit board 11 having a first connection surface 14 and a second connection surface 15 is shown; Figure 1bAn embodiment of a printed circuit board 11' having a connection surface 14 according to the prior art is shown; Figure 2 This is a schematic diagram of an embodiment of the coaxial connector 21; Figure 3 This is a schematic side view of an embodiment of the invention having two adjacent coaxial connectors 21 and 21'; Figure 4 A schematic cross-section of an embodiment of a (radar-based) leveling measuring device; and Figure 5 This is a schematic diagram of an embodiment of a (microwave-based) dielectric measurement device. Detailed Implementation

[0021] Figure 1a The printed circuit board 11' shown corresponds to the prior art and includes four connection surfaces 14 and a conductor path 12. The four corresponding spacers 26 of the coaxial connector 21 are connected to the conductor structure 13 via the four connection surfaces 14. The conductor path 12 is connected to the inner conductor 22 of the coaxial connector 21.

[0022] Figure 1b The printed circuit board 11 shown is used in an exemplary embodiment of the present invention, wherein four additional connection surfaces 15 are provided, through which a conductive connection is established between the outer conductor 23 of the coaxial connector and the conductor structure 13 by means of a shielding element 32. On both sides, the conductor structure 13 is shown by vertical shadow lines, which connects the first connection surface 14 and the second connection surface 15.

[0023] Figure 2 An exemplary embodiment of the coaxial connector 21 shown includes an inner conductor 22. In one embodiment, the inner conductor 22 extends inside a hollow cylindrical outer conductor 23, wherein the two conductors are connected by means of an insulator. The outer conductor 23 is integrally bonded to a polygonal base 24 having end faces 25 forming spacers 26 at its corners and a central hole through which the inner conductor passes for connection to a conductor path 12 on a printed circuit board 11. Each shielding element in the shielding elements 32 is positioned between two spacers 26 at the edge of the end face.

[0024] Figure 3The illustrated embodiment of the invention includes two coaxial connectors 21 and 21' spaced apart by a distance d. In this embodiment, the outer conductor 23 is integrally formed on a polygonal base 24 and electrically connected to a printed circuit board 11 by means of its spacers 26. Furthermore, a gap is formed between the base 24 and the printed circuit board 11. Shielding elements 32, consisting of solder preforms, are integrally integrated into both the base 24 and the connection surface 15 on the sidewalls of the base 24 between each pair of adjacent spacers 26, and serve to reduce the amplitude of interference signals that laterally arise from the interface between the inner conductor 22 and the conductor path 12.

[0025] Figure 4 The illustrated embodiment of the measurement location comprises a field device and a container 44. In one embodiment of the invention, the field device is designed as a (radar-based) fill level measuring device. Therefore, the fill level measuring device can, for example, be arranged on a container 44 containing a medium 45, the fill level of which is the variable to be measured. In this embodiment, the field device includes electronics 41 for generating and evaluating electrical signals. The generated electrical signals are conducted from electronics 41 to an antenna 42 via a coaxial conductor 43 and transmitted by the antenna 42 as radar signals, which are reflected at the surface of the medium 45. This produces a reflected radar signal, which is received by the antenna 42 and conducted back to the electronics 41 via the coaxial conductor 43 as a received signal.

[0026] Figure 5 The embodiment of the invention shown is a microwave-based field device for measuring the dielectric properties of a medium 45. Therefore, the field device can be arranged, for example, on a pipe through which the medium 45 flows. In one embodiment, the field device includes electronics 41, which comprises a unit for generating a transmitted signal and a unit for evaluating a received signal, wherein each of the two units is connected to a separate component according to the invention. The signal generated by the unit for generating the transmitted signal is conducted via a coaxial conductor 43 to a first antenna 42, which radiates the signal as an electromagnetic (microwave) signal into the medium 45. A second antenna 42' receives the (microwave) signal and conducts it as a received signal via the coaxial conductor 43' to the unit for evaluating the received signal.

[0027] List of reference numerals in the attached figures

[0028] 11 Printed Circuit Boards

[0029] 12 conductor paths

[0030] 13 Conductor Structure

[0031] 14 First connecting surface

[0032] 15 Second connecting surface

[0033] 21 coaxial connector

[0034] 22 inner conductor

[0035] 23 outer conductor

[0036] 24 bases

[0037] 25 end face

[0038] 26 spacers

[0039] 31. Gap between coaxial connector and printed circuit board

[0040] 32 shielding components

[0041] 41 Electronic Components

[0042] 42 antennas

[0043] 43 coaxial conductors

[0044] 44 containers

[0045] 45 media

Claims

1. A component comprising: A coaxial connector (21) having: Inner conductor (22). The outer conductor (23) surrounding the inner conductor (22), and The base (24) has an end face (25) and a plurality of spacers (26); Printed circuit board (11), said printed circuit board (11) having: Conductor path (12), and The conductor structure (13) has a plurality of first connection surfaces (14), a plurality of second connection surfaces (15) and a plurality of shielding elements (32). Wherein, the conductor path (12) is electrically isolated from the conductor structure (13); The inner conductor (22) is electrically connected to the conductor path (12). The outer conductor (23) is electrically connected to the conductor structure (13). The base (24) is integrally bonded to the outer conductor (23) or integrally formed on the outer conductor (23); Each spacer (26) from the plurality of spacers is integrally formed on the base (24) and protrudes from the end face (25); The coaxial connector (21) is configured to connect to the coaxial conductor (43) and is arranged on the printed circuit board (11); Each of the spacers (26) is integrally joined to a first engagement position (14) of the conductor structure (13), particularly by means of solder connection; Wherein, a gap (31) is formed between the end face (25) of the base (24) and the printed circuit board (11); In each case, the shielding element (32) is positioned to have space between two adjacent spacers (26) and is integrally integrated into each of the base (24) and the second connecting surface (15).

2. The component according to claim 1, in, The end face (25) of the base (24) has a generally polygonal shape, the generally polygonal shape having at least three corners; The plurality of spacers have one spacer (26) at each corner of the polygon.

3. The component according to claim 2, in, The polygon is a rectangle, especially a square.

4. The component according to any one of claims 1 to 3, in, Spacing-out shielding elements (32) are attached between each pair of adjacent spacers (26); The distances from the shielding element (32) to the two adjacent spacers (26) are substantially equal.

5. The component according to any one of claims 1 to 4, in, The shielding element (32) has a size of 100 micrometers or larger in a direction parallel to the printed circuit board (11).

6. A component assembly comprising at least two components according to any one of claims 1 to 5, in, At least two bases (24 and 24') of at least two coaxial connectors are less than 1 cm apart.

7. A field device for determining a measured variable of a medium, said measured variable being, particularly fill level or dielectric properties, comprising: One or more components or component devices according to at least one of the preceding claims.

8. The field device according to claim 7, further comprising: An electronic device (41) is connected to the component and configured to generate, in particular, an electrical transmission signal at a carrier frequency between 0.03 GHz and 300 GHz, and to determine defined characteristic variables based on the received signal.

9. The field device according to claim 8, further comprising: One or more antennas (42) are used to transmit and / or receive high-frequency electromagnetic signals; One or more coaxial conductors (43) are used to conduct a transmitted signal to one of the one or more antennas and to conduct a received signal received by one of the one or more antennas to one of the components connected to the electronic device (41).

10. A method for measuring position, comprising: The field device according to any one of claims 7 to 9; Container (44) for containing medium (45); The field device is arranged on or attached to the container (44) and connected to the antenna (42) via a coaxial conductor (43). The variable to be determined is the filling level of the medium (45).

11. The field device according to any one of claims 7 to 9, comprising: Container (44), the container (44) being used to contain medium (45), particularly a conduit for guiding medium (45); The electronic device (41) is arranged on or attached to the container (44). The electronic device (41) is connected to two antennas (42 and 42') via two coaxial conductors (43 and 43'). Among them, the measured variable to be determined is the dielectric properties of the medium (41) or one or more measured variables that can be derived from the medium (41); The signal frequency is at least 0.1 GHz and less than 40 GHz, particularly less than 20 GHz.

Images