High-frequency chip arrangement, sensor and manufacturing process

Abstract

High-frequency chip arrangement (100), comprising - a high-frequency chip (112) configured to transmit and receive high-frequency waves, - a cavity-enclosing first housing (114, 115) consisting of a housing cover (115) and a support substrate (114), wherein the first housing (114, 115) surrounds the high-frequency chip (112) when the housing cover (115) is attached to the support substrate (114); - wherein the high-frequency chip (112) is arranged on a top side of the substrate such that it radiates the high-frequency waves away from the substrate (114); - wherein the carrier substrate (114), the high-frequency chip (112) and the first package (114, 115) form a module (110); - a second housing (120) that surrounds at least the module (110), wherein a space (121) between the module (110) and the second housing is filled with a potting compound (104) so ​​that the module (110) is completely surrounded by the potting compound (104) and the high-frequency waves pass through the first housing (114, 115), the potting compound (104), and the second housing (120).

Description

TECHNICAL AREA

[0001] The invention relates to a high-frequency chip arrangement, an industrial sensor and a method for manufacturing the high-frequency chip arrangement. BACKGROUND OF THE INVENTION

[0002] In high-frequency chip assemblies, for example for level sensors, the high-frequency (HF) signal is carried from the HF chip via a bond connection to a separate emitting element, spaced away from the HF chip, which emits the radar waves. The HF chip, to protect the chip and the bond wires, is then encapsulated, for example, with a so-called globtop, i.e., potting compound. When using radar frequencies above 100 GHz, such conventional assembly technologies are no longer feasible. Instead, in these cases, the HF signal is usually emitted directly from the HF chip via a primary radiator. This requires that the chip be operated with as little interference as possible from the surrounding environment. However, for radar sensors used in explosion-proof areas, it is common practice to pot the electronics.This alters the dielectric properties around the chip and worsens its RF properties, making potting the chip impossible.

[0003] Patent application US2006 / 0250298A1 describes a millimeter-wave radar device and module that has a hollow structure while ensuring adequate moisture resistance. Patent application DE19904303A1 describes a housing for a microwave electronic device consisting of three permanently connected parts. Patent application US2010 / 0051982A1 describes a semiconductor device comprising a light-emitting diode chip arranged in a cavity of a semiconductor substrate. Patent application US2022 / 0359328A1 describes a monolithically integrated radar microwave interface (MIMIC) with a back, a front, and side panels, wherein the radar MMIC has a recess extending from the back to the front, at least one antenna on the front, and a lens formed over the recess. SUMMARY OF THE INVENTION

[0004] One objective of the invention could therefore be to provide an improved high-frequency chip arrangement for radar frequencies above 100 GHz in explosion-proof areas.

[0005] The problem is solved by the subject matter of the independent patent claims. Advantageous embodiments are the subject matter of the dependent claims, the following description, and the figures.

[0006] The described embodiments similarly relate to the high-frequency chip assembly, an industrial sensor, and a method for manufacturing the high-frequency chip assembly. Synergies may arise from various combinations of the embodiments, although these may not be described in detail.

[0007] Furthermore, it should be noted that all embodiments of the present invention relating to a method can be carried out in the described sequence of steps; however, this need not be the only and essential sequence of steps of the method. The methods presented here can be carried out with a different sequence of disclosed steps without deviating from the respective method embodiment, unless expressly stated otherwise below.

[0008] Technical terms are used in the usual way. When specific terms are assigned a particular meaning, definitions of the terms are given below, outlining the context in which the terms are used.

[0009] According to a first aspect, a high-frequency chip assembly is provided. The high-frequency chip assembly comprises a high-frequency chip configured to radiate and receive high-frequency waves, and a cavity-enclosing first housing consisting of a housing cover and a substrate, wherein the first housing surrounds the high-frequency chip when the housing cover is attached to the substrate. The high-frequency chip is positioned on the top side of the substrate such that it radiates the high-frequency waves away from the substrate. The substrate, the high-frequency chip, and the first housing together form a module.The high-frequency chip assembly has a second housing that at least surrounds the module, with a space between the module and the second housing being filled with a potting compound so that the module is completely surrounded by the potting compound and the high-frequency waves pass through the first housing, the potting compound, and the second housing.

[0010] The high-frequency chip assembly is particularly suitable for use in potentially explosive atmospheres. This is achieved through the two housings, with the first, inner housing containing a cavity that is filled with gas, air, or a vacuum, thus preserving the dielectric properties around the chip and preventing any degradation of its RF characteristics. A potting compound is located between the first and second housings to ensure explosion protection.

[0011] The second housing surrounds at least the module. The module can, for example, be mounted on a printed circuit board (PCB), so that the second housing also surrounds the PCB. This means that, in this case as well, the module is completely encased in the potting compound. The substrate can be limited to the dimensions of the housing cover, that is, the dimensions of the edges of the housing cover that are in contact with the substrate. In particular, the module can be a self-contained assembly that can then be mounted, soldered, glued, or otherwise attached to the PCB as a module or "package." However, the term "module" is also intended to include the case where the substrate forms a surface of a PCB. The PCB can be considered part of the high-frequency chip assembly.From one perspective, the module can also include the printed circuit board (PCB) or at least the portion of the PCB bounded by the housing. The terms "in the module" or "within the module" are equivalent to "in the first housing" or "within the first housing." The "top" of the substrate refers to the side that is in contact with the housing. The underside of the substrate is, for example, connected to the PCB. The substrate thus forms the basis for the first housing. The housing cover can be made, at least partially, of an RF-transparent material, such as plastic or ceramic, and can tightly seal the housing.

[0012] It is understood that the high-frequency chip arrangement is bidirectional and that it both emits RF waves, for example radar waves, towards a material, and is also reflected and received by the material, even if the direction of reception is not explicitly mentioned or described in all cases in this disclosure. The term "pass" is synonymous with "go through" or "penetrate." This means that the high-frequency waves pass through the first housing, penetrate the potting compound, and pass through the second housing. The high-frequency waves can pass through the second housing, the potting compound, and the first housing in the reverse direction. An essential point of the high-frequency chip arrangement is that the first housing does not contain a potting compound but encloses air, whereas the second housing is filled with a potting compound.The first and second housings are spaced apart from each other in all dimensions, so that the potting compound completely surrounds the module. The arrangement is suitable for use in potentially explosive atmospheres where, for example, gases could ignite. The high-frequency chip is isolated from the environment by this arrangement. Simultaneously, the first housing keeps the potting material away from the high-frequency chip, preventing any adverse effects on its electrical properties regarding wave generation and radiation.

[0013] The following embodiments describe advantageous features for boundary conditions as well as options for how the radar beams are guided through the housings and the potting compound.

[0014] According to one embodiment, the first housing encloses a space whose maximum volume corresponds to an explosion protection rating. Advantageously, the housing encloses a space whose air confinement volume is less than 5 cm³. 3 , 3 cm 3 , or 2 cm 3 , but especially smaller than 1 cm 3 is.

[0015] The size of the air pocket should be sufficiently small to limit the amount of flammable gases or vapors available in the event of an explosion. A specification from a standard might apply here, e.g., less than 1 cm. 3 A smaller air inclusion limits the potential for an explosion. This means the first enclosure is large enough not to degrade the RF characteristics, but also small enough to ensure explosion protection.

[0016] An explosion protection value is a value, such as a threshold value, that has been determined in advance to avoid or prevent an explosion, for example, one that would be triggered by a sudden heat generation, or to keep an explosion small and / or localized. Furthermore, an explosion protection value can be a value or a derived value from a standard.

[0017] According to one embodiment, the module has first means for influencing the radiation opening angle of the high-frequency waves, and the second housing has an area on which the high-frequency waves impinge according to the radiation opening angle and a path of the high-frequency waves at least through the potting compound, which has second means for influencing the radiation opening angle of the high-frequency waves.

[0018] This creates a beam focusing system consisting of several components. The beam angle refers to the angle at which the high-frequency waves are ultimately emitted from the high-frequency chip array. This angle can be influenced by widening, focusing, or guiding the high-frequency waves or the beam of high-frequency waves.

[0019] According to one embodiment, the first means are a dielectric waveguide attached to the high-frequency chip and / or a lens integrated into the first housing.

[0020] The waveguide and the integrated lens can either each individually constitute the primary means or they can be combined. The housing cover of the primary housing, positioned above the high-frequency chip, can, for example, be equipped with a lens contour, referred to here as the lens, which is suitable for focusing or spreading the high-frequency waves or RF signals as required. The high-frequency chip can illuminate the lens directly with a planar structure as the primary radiator or with an attached dielectric waveguide.

[0021] According to one embodiment, the second means are a lens integrated into the second housing, a dielectric waveguide and / or a waveguide.

[0022] The secondary means can also consist of a dielectric waveguide, an integrated lens, or a waveguide, either individually or in any combination where practical. Advantageously, the dielectric waveguide and the waveguide are used in combination. For example, the dielectric waveguide allows signal to be fed into a waveguide, which can then, for instance, power a horn antenna or directly illuminate a dielectric lens. The lens can also be integrated into the secondary housing.

[0023] According to one embodiment, the first means and the second means have concave or convex lenses, or the first means and the second means are concave or convex lenses.

[0024] This allows the beam of high-frequency waves to be widened and / or focused depending on the application, requirements and overall design of the chip arrangement.

[0025] According to one embodiment, the first means and / or the second means have lenses that are convex on one side.

[0026] According to one embodiment, the first means and the second means have lenses, or the first means and the second means are limited in their dimension to an area illuminated by the high-frequency waves.

[0027] This allows for a smaller form factor of the lenses and thus of the arrangement.

[0028] The concave or convex lenses are therefore not necessarily extended over the entire surface of the housing part or wall through which the high-frequency waves pass, but only over the area where the high-frequency waves strike, or where the majority of the waves strike. For example, the lens of the first housing focuses the high-frequency waves, thus narrowly limiting their area of ​​impact. The lens can then be limited to this area.

[0029] According to one embodiment, the first housing and / or the second housing have a flat wall through which the high-frequency waves pass.

[0030] The shape of the housing is, in principle, arbitrary. However, the flat walls make it easy to integrate the lenses.

[0031] According to one embodiment, the wall thickness of a wall of the housing cover through which the high-frequency waves pass is at least 1 mm, and the sum of this wall thickness and a thickness of the potting compound 104 through which the high-frequency waves pass is at least 3 mm.

[0032] According to one embodiment, the wall thickness of the housing cover in an area where the high-frequency waves pass through the housing cover is a multiple of l / 4, where l is the wavelength of the high-frequency waves.

[0033] According to one embodiment, the lens consists of the housing cover, the second housing and the potting compound.

[0034] The potting compound itself is thus part of a lens, e.g., a gradient or multilayer lens. In this case, the two housings can additionally contain a lens, or instead simply represent windows that transmit the high-frequency waves and form the boundary to the lens made of the potting compound. A potting compound with a low dielectric constant and low losses, such as Epic Resins S7391-03, is advantageous. However, other potting compounds, such as Sylgard 517, are also possible with appropriate adjustment. The potting compound can also have different layers with varying permittivity. The potting compound can therefore be part of the beam focusing system.

[0035] According to one embodiment, the distance between the lens integrated in the first housing and the lens of the second housing assumes a defined value that depends on the dielectric properties of the potting compound.

[0036] This means that the length of the path of the high-frequency waves through the potting compound, corresponding to the stated distance, depends on the lensing effects of all the lenses involved.

[0037] According to another aspect, an industrial sensor is provided which has a high-frequency chip arrangement as described herein, as well as electronics connected to the high-frequency chip, and a third housing in which the high-frequency chip arrangement is mounted.

[0038] The industrial sensor is, for example, a level sensor, a limit value sensor, or a radar sensor in robotics applications. Furthermore, a method for manufacturing a high-frequency chip assembly described herein is provided. The method comprises the following steps: In the first step, a high-frequency chip, a housing cover, a second housing, a substrate, a printed circuit board, and a potting compound are provided. In the second step, the high-frequency chip is mounted on the substrate. This can be done, for example, by gluing or soldering. In the third step, the first housing is mounted on the substrate. In the fourth step, the module is soldered onto a printed circuit board. In the fifth step, the module and the printed circuit board are installed in a second housing.In a sixth step, the second housing is potted, so that there is potting compound between the first housing and the second housing, and the first housing is enclosed by the potting compound. BRIEF DESCRIPTION OF THE FIGURES

[0039] Exemplary embodiments of the invention are explained in more detail below with reference to the schematic drawings. Fig. Figure 1 shows a diagram of a first, general embodiment of a high-frequency chip arrangement. Fig. Figure 2 shows a diagram of a second embodiment of a high-frequency chip arrangement. Fig. Figure 3 shows a diagram of a third embodiment of a high-frequency chip arrangement. Fig. Figure 4 shows a diagram of a fourth embodiment of a high-frequency chip arrangement. Fig. Figure 5 shows a diagram of a fifth embodiment of a high-frequency chip arrangement. Fig. Figure 6 shows a flowchart of a process. Fig. Figure 7 shows a diagram of an industrial sensor. DETAILED DESCRIPTION OF THE INVENTION

[0040] Corresponding parts are marked with the same reference symbols in all figures. Examples

[0041] Fig. Figure 1 shows a first embodiment of a high-frequency chip arrangement 100. The high-frequency chip arrangement 100 comprises a high-frequency chip 112 configured to emit and receive high-frequency waves, and a first housing 114, 115 containing a cavity, e.g., air-filled, gas-filled, or vacuum, consisting of a housing cover 115 and a support substrate 114. The housing 114, 115 thus encloses the high-frequency chip 112 when the housing cover 115 is attached to the support substrate 114 and contains a gas-filled interior 106. The housing cover 115 can, for example, be cylindrical with a "bottom" or pot-shaped. However, it can also assume any other shape, such as hemispherical or with a different number of edges.The high-frequency chip 112 is arranged on a top side of the carrier substrate 114, which points into the interior of the housing 114, 115, such that it radiates the high-frequency waves away from the carrier substrate 114, that is, onto the opposite inside of the housing 114, 115. Fig. 1 This is the base of the cylindrical housing cover 115. The support substrate 114, the high-frequency chip 112, and the housing cover 115 of the first housing 114, 115 form a module 110. The high-frequency chip assembly 100 further comprises a second housing 120. The second housing 120 can preferably also be cylindrical or can assume any other geometric shape. Since it preferably also includes a circuit board 102 with further electronic components, i.e., the electronics, on which the module 110 is mounted, the cylindrical second housing is also referred to in this disclosure as an "electronics cup". The second housing 120 surrounds at least the module 110, with a space 121 between the module 110 and the second housing 120 being filled with a potting compound 104, so that the module 110 is completely surrounded by the potting compound 104.The high-frequency waves thus pass through the first housing 114, 115, the potting compound 104, and the second housing 120. More precisely, the high-frequency waves take the path from the high-frequency chip through the gas-filled interior of the housing 106, the bottom of the cylindrical housing cover 115, and the bottom of the second cylindrical housing 120 to the outside. The housing cover 115 is the [missing information] in this example. Fig. 1. Flat. The term "flat housing cover 115" refers to the wall of the housing cover 115 through which the high-frequency waves pass. The same applies to the electronics cup 120. The wall thickness of these walls in the RF propagation area is preferably a multiple of 1 / 4.

[0042] The housing cover 115 consists entirely or partially of an RF-transmitting material, e.g., plastic or ceramic. It is soldered or glued onto the substrate 114, so that the resulting first housing 114, 115 tightly seals the interior 106.

[0043] To ensure explosion protection, the wall thickness of the housing cover 115 is specified as at least 1 mm, and the sum of the wall thickness of the housing cover 115 and the minimum potting compound thickness between the first 114 and 115 is at least 3 mm. The wall thickness of the electronics cup 120 does not need to be considered for explosion protection and can therefore be designed for optimal RF propagation.

[0044] In the Fig. In the embodiment shown in Figure 2, a dielectric waveguide 116 is mounted directly on the high-frequency chip 112. The base of the housing cover 115 has a first lens 118, and the base of the electronics cup 120 or the second housing 120 has a second lens 122. The lenses 118, 122 can be concave, convex, or as shown in Figure 2. Fig. 2 shown, be designed with a concave-convex shape.

[0045] Fig. Figure 3 shows another embodiment in which a primary radiator 117 is mounted directly on the chip 112 or on the carrier substrate 114 on which the high-frequency chip 112 is mounted. In the Fig. In the case shown in Figure 3, lenses 118 and 122 are convex.

[0046] Fig. Figure 4 shows another embodiment with a housing cover 115 which has a convex lens above the high-frequency chip 112 and a half-convex lens in the electronics cup 120.

[0047] Fig. Figure 5 shows a further embodiment with a dielectric waveguide 124 arranged on the electronic cup 120. This can be manufactured as a single piece with the electronic cup 120 or subsequently inserted from a material such as polypropylene (PP), high-density polyethylene (HDPE), polytetrafluoroethylene (PTFE), polyetheretherketone (PEEK), etc. The dielectric waveguide 124, in turn, enables the feed into a waveguide 126, which can then, for example, feed a horn antenna 704 or directly illuminate a dielectric lens.

[0048] The in the Fig. 1, Fig. 2, Fig. 3, Fig. 4 to Fig. The 5 shown forms of the housing cover 115 and the electronics cup 120 can be combined with each other as desired.

[0049] Fig. Figure 6 shows a method for manufacturing a high-frequency chip arrangement 100 described herein. The method comprises the following steps:

[0050] In a first step 602, a high-frequency chip 112 is provided, as well as a housing cover 115, a second housing 120, a carrier substrate 114, a circuit board 102 and a potting compound (104);

[0051] In a second step 604, the high-frequency chip 112 is mounted on the substrate 114. This can be done, for example, by gluing or soldering. In a third step 606, the first housing cover 115 is mounted on the substrate 114 to form a first housing 114, 115 and a module 110. The substrate 114 forms the basis for the housing 114, 115, which can also be referred to as a "package". The housing cover 115 is made, for example, of an RF-transmitting material, such as plastic or ceramic. Thus, a tightly sealed module 110 is created with the RF chip. To meet the explosion protection requirements, the enclosed volume (air inclusion) must be less than 1 cm³. 3The housing cover 115 is equipped above the RF chip 112, for example, with a lens contour, referred to here as the first lens 118, which is suitable for focusing or spreading the RF waves as required. The RF chip 112 can illuminate the first lens 118 directly with a planar structure as a primary radiator or with an attached dielectric waveguide 116. In a fourth step 608, the module 110 is soldered onto a circuit board 102. In a fifth step 610, the module with the circuit board 102 is installed in a second housing 120. In a sixth step 612, the second housing 120 is potted, i.e., the potting compound 104 is poured in, so that there is potting compound 104 between the first housing 114, 115 and the second housing 120 and the first housing 114, 115 is enclosed by the potting compound 104.The distance between the lens 118 integrated in the housing cover 115 and the lens 122 incorporated in the electronics cup 120 is defined and depends on the dielectric properties of the potting compound 104. A potting compound with a low dielectric constant and low losses, such as Epic Resins S7391-03, is advantageous. However, other potting compounds, such as Sylgard 517, are also possible with appropriate adjustment. The resulting multilayer or gradient lens can be used to illuminate another lens in a multi-lens system and to direct the RF energy towards the contents. To meet further explosion protection requirements, the wall thickness of the housing cover 115 must be at least 1 mm, and the sum of the wall thickness of the housing cover 115 and the potting compound thickness must be at least 3 mm.

[0052] Fig. Figure 7 shows an industrial sensor with the high-frequency chip arrangement 100 and a housing 702 of the sensor 700, which is referred to here as the third housing 702. In the example of the Fig. 7 is the embodiment according to Fig. 5. However, any other embodiment described herein may also be used. An industrial sensor is, for example, a level sensor, a limit level sensor, a pressure sensor, or a sensor that measures the density or composition / mixture of a substance during a process. Such a sensor can be used, in particular, in process automation. However, such an industrial sensor could also be, for example, a radar sensor used in robotics.

[0053] Other variations of the disclosed embodiments can be understood and carried out by a person skilled in the art when carrying out the claimed invention by studying the drawings, the disclosure, and the accompanying claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit can perform the functions of several items or steps listed in the claims. The mere fact that certain measures are specified in interdependent claims does not mean that a combination of these measures cannot be advantageously used. Reference numerals in the claims should not be interpreted as limiting the scope of the claims. Reference symbol list 100 high-frequency chip arrangement 102 Printed circuit board, circuit board 104 Potting compound 106 Cavity containing air or gas or vacuum 110 Module 112 High-frequency chip 114 Support substrate, base of the first housing 115 Housing cover of the first housing 116 dielectric waveguides 117 primary radiators 118 first lens 120 second housing, electronics cup 121 Space between the module and the second housing 122 second lens 124 dielectric waveguides on the electronics cup 126 waveguides 700 industrial sensor 702 third housing; housing of the industrial sensor 704 Horn antenna

Claims

A high-frequency chip arrangement (100) comprising: - a high-frequency chip (112) configured to radiate and receive high-frequency waves; - a cavity-enclosing first housing (114, 115) comprising a housing cover (115) and a carrier substrate (114), wherein the first housing (114, 115) surrounds the high-frequency chip (112) when the housing cover (115) is attached to the carrier substrate (114); - wherein the high-frequency chip (112) is arranged on a top surface of the carrier substrate such that it radiates the high-frequency waves away from the carrier substrate (114); - wherein the carrier substrate (114), the high-frequency chip (112) and the first housing (114, 115) form a module (110);- a second housing (120) that surrounds at least the module (110), wherein a space (121) between the module (110) and the second housing is filled with a potting compound (104) so ​​that the module (110) is completely surrounded by the potting compound (104) and the high-frequency waves pass through the first housing (114, 115), the potting compound (104), and the second housing (120). High-frequency chip arrangement (100) according to claim 1, wherein the first housing (114, 115) encloses a space whose maximum volume corresponds to an explosion protection value. High-frequency chip arrangement (100) according to one of claims 1 or 2, wherein the module (110) has first means for influencing the radiation opening angle of the high-frequency waves and the second housing (120) has an area on which the high-frequency waves impinge according to the radiation opening angle and a path of the high-frequency waves at least through the potting compound (104), which has second means for influencing the radiation opening angle of the high-frequency waves. High-frequency chip arrangement (100) according to claim 3, wherein the first means is a first lens (118) integrated into the first housing (114, 115) and / or a dielectric waveguide (116) attached to the high-frequency chip (112). High-frequency chip arrangement (100) according to claim 3 or 4, wherein the second means are a lens (122) integrated into the second housing (120), a dielectric waveguide (124) and / or a waveguide (126). High-frequency chip arrangement (100) according to claim 3, wherein the first means and / or the second means have concave or convex lenses (118, 122). High-frequency chip arrangement (100) according to one of claims 3 to 6, wherein the first means and / or the second means have half-convex lenses (118, 122). High-frequency chip arrangement (100) according to one of claims 3 to 7, wherein the first means and the second means have lenses (118, 122) whose dimension is limited to an area illuminated by the high-frequency waves. High-frequency chip arrangement (100) according to one of the preceding claims, wherein the first housing (114, 115) and / or the second housing (120) has a flat wall through which the high-frequency waves pass. High-frequency chip arrangement (100) according to one of the preceding claims, wherein a wall thickness of a wall of the housing cover (115) through which the high-frequency waves pass is at least 1 mm, and the sum of this wall thickness and a thickness of the potting compound (104) through which the high-frequency waves pass is at least 3 mm. High-frequency chip arrangement (100) according to one of the preceding claims, wherein a wall thickness of the housing cover (115) in an area through which the high-frequency waves pass the housing cover (115) is a multiple of l / 4, where l is the wavelength of the high-frequency wave. High-frequency chip arrangement (100) according to one of the preceding claims, wherein the lens consists of the housing cover, the second housing and the potting compound. High-frequency chip arrangement (100) according to one of claims 5 to 12, wherein the distance between the lens (118) integrated in the housing cover (115) and the lens (122) of the second housing (120) assumes a defined value which depends on the dielectric properties of the potting compound (104). Industrial sensor (700) comprising a high-frequency chip arrangement (100) according to one of the preceding claims, and further comprising electronics connected to the high-frequency chip (112), and a third housing (702) in which the high-frequency chip arrangement (100) is mounted. A method for manufacturing a high-frequency chip assembly (100) according to any one of claims 1 to 13, comprising the steps of: providing (602) a high-frequency chip (112), a housing cover (115), a second housing (120), a support substrate (114), a printed circuit board (102), and a potting compound (104); mounting (604) the high-frequency chip (112) onto the support substrate; mounting (606) the first housing cover (115) onto the support substrate (114) to obtain a first housing (114, 115) and a module (110); soldering (608) the module (110) onto the printed circuit board (102); installing (610) the module (110) with the printed circuit board (102) into the second housing (120); potting (612) the second housing (120). so that the potting compound (104) is located between the first housing (114, 115) and the second housing (120) and the first housing (114, 115) is enclosed by the potting compound (104).

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