Device for mode interlacing

Abstract

Device (1) for mode swirling, with a reflector body (2) designed for mode swirling, and with a covering (3) which surrounds the reflector body (2), wherein the reflector body (2) and the covering (3) form a movement unit (5), which movement unit (5) is rotatable about a rotation axis (6) for the purpose of mode swirling.

Description

[0001] The invention relates to a device for mode reverberation and a mode reverberation chamber.

[0002] A reverberation chamber is a measurement and testing environment in the field of electromagnetic compatibility. Similar to an anechoic chamber, the chamber is used either for measuring interference emissions, i.e., measuring the interference emitted by an electrical or electronic device, or for testing a device's immunity to high-frequency electromagnetic fields.

[0003] Unlike anechoic chambers, a mode reverberation chamber is not equipped with internal absorbers to prevent reflections. Instead, the chamber is electromagnetically shielded (cavity resonator), and the electromagnetic fields introduced more or less randomly into the chamber for testing purposes by a transmitting antenna are reflected multiple times by the chamber's metallic walls, resulting in the excitation of so-called modes.

[0004] It is known to randomly vary the electromagnetic field within the chamber by means of a device for mode swirling arranged in the chamber in the form of a mechanical mode stirrer in order to achieve a statistically uniform distribution of the field strengths in the chamber and thus a measurement environment that is as homogeneous as possible.

[0005] The application of such a mode reverberation chamber is described, for example, in the standard IEC 61000-4-21.

[0006] It is known from the prior art to use a rotatable metallic reflector structure irradiated by the transmitting antenna as a mode stirrer. This reflector structure rotates around its own axis during the measurement. The reflector structure, which can be designed, for example, like a propeller, with the propeller blades forming the reflector surfaces, can be housed in a stationary housing.

[0007] One of the disadvantages of this type of directional stirrer is that the rotation of the reflector structure not only causes unwanted air movement but also places significant mechanical stress on the structure. Therefore, the design effort required to ensure safe operation of such a directional stirrer is comparatively high, especially with large reflector diameters and high rotation speeds.

[0008] One object of the invention is to enable mode swirling at high rotational speeds with comparatively low design effort. This object is achieved by a device according to claim 1 and a mode swirling chamber according to claim 11.

[0009] The device for mode swirling according to the invention comprises a reflector body designed for mode swirling and a covering which surrounds the reflector body, wherein the reflector body and the covering form a movement unit which is rotatable about an axis of rotation for the purpose of mode swirling.

[0010] The advantages and embodiments explained below in connection with the device according to the invention also apply mutatis mutandis to the mode swirling chamber and vice versa.

[0011] Advantageous embodiments of the invention are specified in the subclaims or result from the following description and / or the attached figures.

[0012] The invention provides a device for mode swirling, which is also referred to below as a mode stirrer. The mode stirrer, like any other mode stirrer, has a reflector body designed for mode swirling. Unlike the prior art, however, the mode stirrer according to the invention does not require the reflector body itself to be rotatable, i.e., to rotate about its own axis. Instead, the reflector body, together with the surrounding casing, forms a movement unit that can rotate about an axis independent of the reflector body.

[0013] In this way, the principle of a structural separation of the reflector body from its axis of rotation is realized according to the invention. A structural separation of the reflector body from its axis of rotation means that the axis around which the reflector body rotates during operation of the mode stirrer is independent of, i.e., separate from, the construction of the reflector body itself. This is due to the fact that it is the moving unit that rotates around an axis of rotation during and for the purpose of mode swirling. The reflector body neither requires a physical axis of rotation nor does the reflector body have to be designed in such a way that it specifies or suggests a specific axis of rotation. Instead, the axis of rotation around which the moving unit rotates for the purpose of mode swirling can be formed or determined exclusively by the casing surrounding the reflector body.

[0014] A basic idea of the invention is that the turbulence of the modes is no longer caused by the reflector structure itself rotating about its own axis. Instead, it is proposed to surround a suitable reflector body with a covering in such a way that a moving unit consisting of the reflector body and the covering is created, which moving unit is preferably held in an operating position by a separate holding device in which the moving unit can rotate about an axis of rotation. In other words, it is not the reflector body itself that is set in rotation, but the moving unit, which comprises both the reflector body and the covering. This results in numerous advantages. Firstly, the reflector body can be designed in almost any shape and size. Multi-part reflector bodies are also possible.In this way, the design of the reflector bodies can vary depending on the desired type of modal swirl. Furthermore, the design of the cladding can minimize the occurrence of air movements during the modal swirl process. Overall, the design effort is significantly reduced compared to prior art solutions. Very high rotational speeds can be achieved with comparatively little design effort without causing swirls or turbulence.

[0015] According to a preferred embodiment of the invention, the covering surrounding the reflector body is designed as a dimensionally stable solid structure which surrounds the reflector body, forming a movement unit for jointly performing a rotational movement.

[0016] According to a preferred embodiment of the invention, the casing is rotationally symmetrical to prevent the occurrence of imbalances during rotation. This reduces vibrations and bearing loads, lowers drive energy consumption, and increases mechanical stability. If a casing that is not rotationally symmetrical is used, disruptive vibrations can be avoided with the help of imbalance compensation (e.g., counterweights).

[0017] According to a preferred embodiment of the invention, the cladding is designed in the simplest case as an open solid-state structure in the manner of a lattice cage, which surrounds the reflector body to form a movement unit for jointly performing a rotational movement.

[0018] According to a preferred embodiment of the invention, the covering is closed, preferably in such a way that the covering is a casing structure that encloses the reflector body. In other words, a closed enclosure designed as a shell accommodates the reflector body within its interior.

[0019] While the reflector body does not necessarily have to be completely surrounded by the casing when using a mesh cage or the like, it is advantageous for reducing air movement, eddies, or turbulence if, according to a preferred embodiment of the invention, the reflector body is located entirely inside the casing (shell). In other words, the shell acts as a casing structure and completely encloses the reflector body. In this case, the casing volume must be large enough to accommodate the reflector body selected for this mode stirrer in the desired position. The casing provides a receiving volume for the reflector body. The size of the receiving volume limits the maximum dimensions of the reflector body.

[0020] According to a preferred embodiment of the invention, the reflector body is inserted or embedded into the casing structure. In this way, the reflector body is integrated into the casing structure. This is particularly true in a particularly advantageous embodiment of the invention in which the reflector body is positively received in the casing structure. This allows a particularly simple and reliable production of a moving unit comprising the reflector body and the covering. A suitable casing structure is preferably formed by a molded body made of solid material.

[0021] The casing structure preferably consists of a material which, on the one hand, is sufficiently strong to withstand the forces acting on the casing at high speeds, but, on the other hand, influences the measuring environment as little as possible, in particular absorbs no or only little field energy.

[0022] Materials that do not influence the measurement environment include Styrofoam and Styrodur. Other materials that absorb field energy but are extremely advantageous in terms of stability include glass fiber reinforced plastics (GRP) and other plastic materials. Another advantage is that cladding made of such plastics can be manufactured particularly easily using additive manufacturing processes, such as 3D printing.

[0023] Advantageously, the sheathing structure is made of a material that is particularly easy to process and work with little effort, allowing the sheathing structure to be particularly easily adapted to the shape of the reflector body, either during its manufacture or subsequently. The materials mentioned above are also well suited from this perspective.

[0024] According to a preferred embodiment of the invention, the outer shape of the fairing is designed from an aerodynamic point of view in such a way that the air resistance of the rotating movement unit is as low as possible and / or in such a way that air movements, eddies or turbulences are minimized when the movement unit rotates.

[0025] The same general statements apply to the material of the support structure as to the material of the casing, particularly with regard to material properties in terms of strength and influence of the measuring environment. In practice, support structures made of GRP have proven particularly effective.

[0026] In principle, the present invention allows the use of a reflector body that can have any shape suitable for mode swirling. Due to the inventive principle of structurally separating the reflector body from its axis of rotation, the question of whether and how the reflector body can be rotated about its own axis is no longer relevant to its design. According to a preferred embodiment of the invention, the reflector body has no physical axis of rotation.

[0027] According to a preferred embodiment of the invention, the reflector body is essentially disk-shaped, spiral-shaped, or helical. Since the reflector body itself does not need to be rotated, the number, shape, and size of the reflector surfaces of the reflector body can be selected in almost any manner depending on the desired reflector functionality or desired mode swirling. Disc-shaped reflector bodies, for example, have proven particularly suitable, in particular with spiral-shaped or helical-shaped reflector surfaces. Very good results can also be achieved with perforated discs (perforated discs). Instead of essentially two-dimensional reflector bodies, in particular disk-shaped ones, whereby this refers to bodies whose extension in one spatial direction is very small compared to the other two dimensions, "true" three-dimensional reflector bodies can also be used.

[0028] It is particularly advantageous that the design of the reflector body can focus exclusively on its suitability for mode swirling. This is based on the inventive concept, according to which the only important factor is that the cladding—together with the reflector body located inside and / or enclosed by the cladding—can be set in rotation, whereas the suitability of the single- or multi-part reflector body for performing a rotation no longer plays a role.

[0029] In tests, disc-shaped reflector bodies with a diameter of approximately 2 m at a speed of 260 rpm and disc-shaped reflector bodies with a diameter of 4 m at a speed of 120 rpm were successfully used.

[0030] According to a preferred embodiment of the invention, the reflector body is constructed in multiple parts. A reflector body constructed in this way allows for the generation of mode turbulences that are impossible or very difficult to generate with single-piece reflector bodies. The use of multi-piece reflector bodies is particularly easy due to the inventive principle of structurally separating the reflector body from its axis of rotation, particularly when the reflector body is inserted or embedded in the cladding.

[0031] According to a preferred embodiment of the invention, the reflector body is held in its operating position in the cladding by suitable fastening means. In the case of embedding, the cladding itself can serve as a fastening means to create a positive fit. If the reflector body is not embedded in the cladding, holding elements of the cladding, for example connecting devices integrally provided on a grid structure, serve to create a mechanical connection between the reflector body and the cladding. According to a preferred embodiment of the invention, the reflector body is glued to a cladding made of solid material, resulting in a type of composite element with a reflector body embedded inside the cladding.

[0032] According to a preferred embodiment of the invention, the reflector body is arranged obliquely with respect to the axis of rotation. This means that the reflector body is oriented obliquely or inclined to the axis of rotation around which the moving unit rotates during mode reverberation.

[0033] An advantage of the invention is that the reflector body can, in principle, be arranged in any position within the receiving volume of the cladding. Especially for disc-shaped reflector bodies, an arrangement inclined with respect to the axis of rotation of the cladding has proven particularly advantageous for mode swirling.

[0034] For rotationally symmetrical fairings, according to a preferred embodiment of the invention, the reflector body is positioned obliquely with respect to the fairing's axis of symmetry. This allows for the realization of special mode-swirling functionalities.

[0035] The reflector body is metallic, meaning it is made of an electrically conductive material. The reflector body is preferably made of aluminum. However, other suitable materials can also be used.

[0036] According to a preferred embodiment of the invention, the mode stirrer comprises a holding device that holds the movement unit in an operating position. In this operating position, the movement unit is rotatable about its axis of rotation for the purpose of mode swirling.

[0037] According to a preferred embodiment of the invention, the rotational axis about which the movement unit held by the holding device is rotatable is designed as a stationary rotational axis. Preferably, the rotational axis is defined or fixed by the structural design of the casing.

[0038] According to a preferred embodiment of the invention, the casing is rotationally symmetrical, and the axis of rotation lies along a symmetry axis of the casing. This prevents vibrations and uneven loading of the bearings. The uniform mass distribution ensures stable rotation. Energy losses in bearings and drives are also reduced.

[0039] Notwithstanding the inventive principle of a constructive separation of the reflector body from the axis of rotation of the movement unit, the rotation of the movement unit during mode swirling can also take place about an axis of rotation that lies on an axis of symmetry and / or an inherent axis of rotation of the reflector body.

[0040] The rotary drive of the movement unit can be implemented in various advantageous ways.

[0041] According to a preferred embodiment of the invention, the rotational axis is formed by a drive shaft connected to the casing, which drive shaft can be driven by a shaft drive. This means that the rotational movement is transmitted to the casing via a drive shaft. To achieve the rotation of the movement unit, a shaft drive is provided, preferably located outside the casing, which drives the drive shaft. The drive of the drive shaft by the shaft drive can be direct or indirect, or directly or indirectly.

[0042] According to a preferred embodiment of the invention, the drive shaft is connected to the cover in a rotationally fixed manner, in particular designed as a single piece or integrally with the cover.

[0043] According to a preferred embodiment of the invention, the drive shaft connected to the cover is mounted in a number of bearings which are provided by the holding device and are designed to support the drive shaft.

[0044] According to a preferred embodiment of the invention, the drive shaft is connected exclusively to the fairing, but not to the reflector body. Therefore, the forces transmitted to the drive shaft do not act directly on the reflector body. The reflector body is not set in rotation directly, but exclusively via the surrounding fairing.

[0045] As an alternative to this type of rotary drive of the cover, it can be provided according to another embodiment of the invention that the cover does not require a drive shaft.

[0046] According to a preferred embodiment of the invention, the cladding, together with the reflector body, is rotatable about a preferably fixed support axis and can be driven by a rotary drive. In this case, the movement unit is set in rotation directly or indirectly by an external drive, which is preferably designed as an edge or circumferential drive. This rotary drive acts directly on the circumference of the cladding. In this case, the outer shape of the cladding is designed in a suitable manner. The edge drive can, for example, be designed as a friction wheel drive or as a cable or belt drive.

[0047] According to a preferred embodiment of the invention, in this case the holding device provides a number of bearings for the supporting axis of the fairing and the fairing is rotatably mounted on the supporting axis.

[0048] According to a preferred embodiment of the invention, the holding device is designed such that it interchangeably accommodates the casing together with the encased reflector body. In other words, such holding devices can be combined with different movement units as needed. In this way, a mode reverberation chamber can be easily equipped with different mode stirrers. Preferably, the holding device and / or the casing are designed such that the movement unit can be exchanged, regardless of the type of rotary drive used.

[0049] According to a preferred embodiment of the invention, the holding device is surrounded by an external housing, in particular, encased in such a housing. If the holding device, together with the movement unit comprising the cover and reflector body held by it, is also housed in such a housing, air movements, eddies, or turbulence caused by the rotation of the movement unit during mode reverberation can be almost completely avoided, even if the mode reverberation occurs at very high speeds. An external housing also serves as contact protection and thus as an additional protective measure for persons in the mode reverberation chamber.

[0050] The same general statements apply to the material of the enclosure as to the material of the cladding and the support structure, particularly with regard to material properties related to strength and influence on the measuring environment. In practice, enclosures made of GRP have proven particularly effective.

[0051] The mode swirling chamber according to the invention comprises at least one mode swirling device (mode stirrer) as described here.

[0052] According to a preferred embodiment of the invention, the reverberation chamber comprises at least one antenna suitable for carrying out the immunity and / or emission measurements.

[0053] The mode stirrer according to the invention can be either permanently installed or mobile in the mode swirling chamber according to the invention. Both the position and orientation of the mode stirrer within the chamber can be selected almost arbitrarily. Thus, the rotation axis of the movement unit can be horizontal, vertical, or at any other angle, and the mode stirrer can be mounted, for example, on the chamber wall or on the chamber ceiling.

[0054] According to a preferred embodiment of the invention, several mode stirrers are arranged in the chamber at the same time, in particular mode stirrers which are provided with different reflector bodies and / or mode stirrers which, in particular due to the number, shape and size of the reflector surfaces, have different reflector body functionalities and / or mode stirrers which can be operated at different speeds.

[0055] According to a preferred embodiment of the invention, several fixedly installed mode stirrers of different designs are arranged in the chamber together with at least one mode stirrer which can be positioned in the chamber in a variable manner.

[0056] These chambers are suitable for a wide range of immunity and emission measurements.

[0057] A method for mode swirling resulting from the application of the invention is characterized in that a device for mode swirling is located in a mode swirling chamber, wherein the device for mode swirling has a reflector body designed for mode swirling and a covering surrounding the reflector body, wherein the reflector body and the covering form a movement unit, and wherein the movement unit is rotated about an axis of rotation for the purpose of mode swirling.

[0058] The invention is particularly, but not exclusively, applicable to EMC investigations, particularly in interference emission measurements and in immunity testing. The modal reverberation chamber according to the invention can replace conventional EMC absorber chambers. Furthermore, the modal reverberation chamber according to the invention can be used wherever complex electromagnetic environments are to be realistically simulated or electromagnetic properties are to be statistically evaluated.

[0059] An embodiment of the invention is explained in more detail below with reference to the drawings, in which: Fig. 1 a schematic representation of a mode stirrer, Fig. 2 a schematic representation of a movement unit, Fig. 3 a schematic representation of a movement unit (section), Fig. 4 a schematic representation of a mode reverberation chamber (section).

[0060] All figures depict the invention not to scale, but merely schematically and with only its essential components. Like reference numerals correspond to elements with the same or comparable function.

[0061] A device 1 for mode swirling (mode stirrer), as in Fig. 1, comprises a reflector body 2 designed for mode swirling, which in this example is made of an aluminum material, and a dimensionally stable, cylindrical covering 3 which surrounds the reflector body 2 in the manner of a shell.

[0062] The one-piece reflector body 2, not further illustrated in the drawings, is, for example, disc-shaped and has defined, spiral-shaped reflector surfaces 4. The reflector body 2 has no physical axis of rotation or the like.

[0063] The cover 3, which in this example is made of a plastic material and is individually adapted to the reflector body 2 by means of 3D printing, is designed to be closed in such a way that it is a casing structure that completely encloses the reflector body 2, see Fig. 2. The reflector body 2 is embedded in the casing structure in a form-fitting manner, as shown in Fig. 3. In this example, the cover 3 is made of solid material and has precisely fitting receptacles for the reflector body 2. Instead of the plastic solid body, a Styrodur solid body can also be used as the cover 3 for the form-fitting embedding of the reflector body 2. An alternative cover made of GRP material, designed as a grid structure with holding elements for the reflector body 2 and adapted to the reflector body 2, is also possible, but is not shown here.

[0064] In this way, the reflector body 2 and the covering 3 form a movement unit 5. The movement unit 5 is rotatable about a fixed axis of rotation 6 for the purpose of mode swirling. The covering 3 is rotationally symmetrical and the axis of rotation 6 lies along an axis of symmetry of the covering 3. Fig. 3 it can be seen that the reflector body 2 is arranged inside the casing 3 obliquely with respect to the axis of rotation 6 of the movement unit 5.

[0065] A holding device 7 made of GRP holds the movement unit 5 in a Fig. 1, in which the movement unit 5 is rotatable about its axis of rotation 6. The axis of rotation 6 is formed by a drive shaft 8 that is suitably connected to the casing 3 for rotational stability and is mounted in bearings (not shown in detail) of the holding device 7. The drive shaft 8 can be driven by a shaft drive 9, which is also held by the holding device 7 and is designed as an electric motor drive in this example. Instead of an electric motor drive, a pneumatic drive, for example, can also be used.

[0066] In Fig. 1 not shown is an optional outer housing, also made of GRP, which completely surrounds the holding device 7. Such a housing limits air movements caused by the rotation of the movement unit 5 to the interior of the housing and serves as contact protection.

[0067] A mode reverberation chamber 10 is in Fig. 4. The electrical or electronic device 11 to be tested is arranged inside the chamber 10, which is designed as a cavity resonator, as well as an antenna 12 and several mode stirrers, including a first mode stirrer 16 with a horizontal axis of rotation, fixed to a wall 13 of the chamber 10, a second mode stirrer 17 with a vertical axis of rotation, fixed to the ceiling 14 of the chamber 10, and a third mode stirrer 18, arranged in a variable position within the chamber 10 and freely movable on the chamber floor 15, whose axis of rotation can be arranged at any angle to the vertical with the aid of a suitably designed holding device. A large number of different mode swirls can be realized in such a chamber 10.

[0068] All features presented in the description, the following claims, and the drawings may be essential to the invention, both individually and in any combination. These features or combinations of features may each constitute an independent invention, the use of which is expressly reserved.

[0069] When specifying a combination of features defining an invention, individual features from the description of an embodiment need not necessarily be combined with one or more or all other features specified in the description of that embodiment; in this respect, each sub-combination of features of one or more embodiments is expressly disclosed.

[0070] Furthermore, physical features of the devices can be reformulated to be used as process features, and process features can be reformulated to be used as physical features of the devices. Features reformulated in this way are implicitly disclosed. List of reference symbols 1 device for mode swirling (mode stirrer) 2 reflector bodies 3 Covering, storage volume 4 Reflector surface 5 movement units 6 axis of rotation 7 Holding device 8 Drive shaft 9 Shaft drive 10 Mode reverberation chamber 11 Device to be tested 12 Antenna 13 Chamber wall 14 Chamber ceiling 15 Chamber floor 16 first fashion stirrer 17 second fashion stirrer 18 third fashion stirrer

Claims

[1] Device (1) for mode swirling, with a reflector body (2) designed for mode swirling, and with a covering (3) which surrounds the reflector body (2), wherein the reflector body (2) and the covering (3) form a movement unit (5), which movement unit (5) is rotatable about a rotation axis (6) for the purpose of mode swirling. [2] Device (1) according to claim 1, wherein the covering (3) is closed, preferably such that the covering (3) is a casing structure which encloses the reflector body (2). [3] Device (1) according to claim 2, wherein the reflector body (2) is inserted or embedded in the casing structure. [4] Device (1) according to one of claims 1 to 3, wherein the reflector body (2) is designed in several parts. [5] Device (1) according to one of claims 1 to 4, wherein the reflector body (2) is arranged obliquely with respect to the axis of rotation (6) of the movement unit (5). [6] Device (1) according to one of claims 1 to 5, with a holding device (7) which holds the movement unit (5) in an operating position in which the movement unit (5) is rotatable about its axis of rotation (6). [7] Device (1) according to one of claims 1 to 6, wherein the covering (3) is rotationally symmetrical and the axis of rotation (6) lies along an axis of symmetry of the covering (3). [8] Device (1) according to one of claims 1 to 7, wherein the axis of rotation (6) is formed by a drive shaft (8) connected to the casing (3), which drive shaft (8) can be driven by a shaft drive (9). [9] Device (1) according to one of claims 1 to 7, wherein the covering (3) together with the reflector body (2) is rotatable about a support axis and can be driven by a rotary drive. [10] Device (1) according to one of claims 1 to 9, wherein the holding device (7) is surrounded by an outer housing. [11] Mode reverberation chamber (10) with at least one device (1) according to one of claims 1 to 10.

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