Reduction of vibrations in electronic components by means of vibroacoustic metamaterials

Abstract

The invention relates to a device for reducing mechanical vibrations in an electronic component (1), comprising an assembly (2) of local resonators (3) which are matched such that each resonator has at least one natural frequency in a relevant frequency range, wherein the assembly (2) of local resonators (3) is configured so as to generate at least one stop band for the propagation of mechanical waves in the electronic component (1) in the relevant frequency range.

Description

[0001] Vibration reduction of electronic components using vibroacoustic metamaterials

[0002] The invention relates to a device for vibration reduction in electronic components based on vibroacoustic metamaterials.

[0003] Mechanical vibrations represent a significant form of stress on electrical components, which can reduce their service life and significantly increase their probability of failure. For example, vibrations can cause fatigue fractures in contact points, which in the worst case could lead to system failures. Likewise, high mechanical loads can temporarily impair the functionality of electronic components. Capacitors, diodes, and transistors are particularly affected by these problems, but also more complex components such as sensors and integrated circuits. In addition to the reduced reliability of the affected electronic systems and increased maintenance requirements, mechanical vibrations can therefore also pose safety-related problems in areas such as automotive or aerospace engineering.

[0004] To reduce the stress on these electronic components due to mechanical vibrations, connecting elements made of silicone or elastomers are used, for example, to decouple printed circuit boards from vibration-transmitting components. However, such a "soft" connection is not practical or desirable under all conditions and is ineffective, for example, when connecting printed circuit boards to cables. Encapsulating the affected components in a potting compound can also protect them from the effects of vibrations; however, such encapsulations can also negatively impact the function of some components and generally increase the space required. However, if vibrations cannot be avoided or the components cannot be effectively protected, special components are often used.These are more robustly designed, sometimes oversized, and feature additional contacts, for example, to ensure a secure connection of the components to a circuit board. However, it goes without saying that such components have disadvantages in terms of mass and space requirements in many applications.

[0005] Vibroacoustic metamaterials can be used to overcome the disadvantages of conventional methods for vibration damping in electronic components. Metamaterials are artificial, usually periodic, structures designed to achieve special conductive, insulating, damping, or amplifying properties. In this way, structures can be designed that form stop bands, for example. Stop bands are frequency ranges in which wave propagation is greatly attenuated. In vibroacoustic metamaterials, this concept is applied to control and manipulate the propagation of mechanical waves. In this context, the properties of solids, such as density, bulk modulus, and elastic modulus, are relevant. One possibility for generating stop bands using vibroacoustic metamaterials is periodic arrangements of resonant structures, so-called local resonators.Due to the interactions of the local resonators with their environment, the resulting structure behaves as if it had a negative effective mass within a specific frequency range, severely impeding wave propagation within that range. To create a pronounced stopband, the individual resonators must all be tuned to the same frequency. Deviations in the periodicity and frequency tuning of the resonators result in a broader, but less pronounced, stopband. Through clever design of vibroacoustic metamaterials, a desired frequency range can be set in which the propagation of mechanical vibrations is damped.

[0006] The object of this patent application is therefore to propose a device that dampens the propagation of mechanical vibrations in a specific frequency range. At the same time, this device should offer advantages over conventional methods for vibration damping on electronic components in terms of space requirements, weight, heat dissipation, and handling.

[0007] This object is achieved by a device for reducing mechanical vibrations in an electronic component according to independent claim 1.

[0008] Such a device for reducing mechanical vibrations in an electronic component comprises an array of local resonators, each tuned to have at least one natural frequency in a relevant frequency range, wherein the array of local resonators is configured to generate at least one stopband for mechanical wave propagation in the electronic component in the relevant frequency range. Electronic components include, for example, electrical components such as capacitors, resistors, coils, diodes, and transistors, but also more complex components such as sensors and integrated circuits. Within the scope of this application, however, the term "electronic components" shall also extend to elements such as connectors, cables, switches, and relays, as well as to other electrical, electromechanical, or mechanical components used in electronic devices and systems.

[0009] To reduce vibration, the electronic component is equipped with an array of local resonators. This array of local resonators forms a vibroacoustic metamaterial. The array can be two-dimensional, i.e., in a plane, or three-dimensional in space. The individual resonators each consist of at least one vibrating mass and one spring element. The vibrating mass can have any shape and size and be made of different materials. The mass of the vibrating mass is an important factor in tuning the frequency of the resonator. The spring element has elastic properties. The spring element can be formed integrally with the vibrating mass. It can also be a single elastic element, such as a leaf spring. The spring element can have any shape and size.In particular, the shape and dimensions of the spring element are important factors in tuning the frequency of the resonator. The spring element can be made of the same material as the vibrating mass, or, for example, an elastomer. It should be noted that the vibrating mass and the spring element are not necessarily clearly distinguishable from each other. The vibrating mass and spring element can be formed as one piece, and the vibrating mass can also deform during vibration. The vibrating mass, the spring element, and a certain area surrounding the resonator form a unit cell of the resonator. The arrangement of local resonators consists of a spatial repetition of these unit cells.

[0010] Each individual resonator has at least one first relevant resonant frequency. When excited at a resonant frequency, the amplitude of the resonator's oscillation reaches its maximum. The resonant frequency of a resonator is determined by the properties of the entire unit cell. In addition to the mass of the oscillating mass and the spring element, and the elastic properties of the spring element, the geometry, mass, and elasticity of the surrounding structures also play a role. The frequency of the resonators can therefore be tuned by varying these properties. The unit cells should be dimensioned on the order of half a wavelength of the first relevant frequency, or smaller.

[0011] All local resonators of the metamaterial are tuned to the same, or at least approximately the same, resonant frequency. This creates a stopband around this frequency, which significantly attenuates wave propagation in the metamaterial and in the electronic component it contains. By tuning the resonant frequency of the local resonators, a stopband can be created that limits the propagation of mechanical waves in the electronic component. If the resonators have multiple resonant frequencies in the relevant frequency range, multiple stopbands can be created around them. These multiple stopbands can separately reduce oscillations in different frequency ranges or overlap to form a large stopband.

[0012] The arrangement of local resonators can be periodic. A periodic structure results from the spatial repetition of the unit cells of the local resonators.

[0013] The spacing of the local resonators in the array of local resonators can be less than half a wavelength of the first relevant frequency to ensure favorable behavior of the array. Together with unit cells of the local resonators on the order of half a wavelength of the first frequency, the dispersion behavior of the array can also be direction-independent.

[0014] The periodic arrangement of the local resonators with spacings of less than or equal to half a wavelength also allows at least one additional stop band to form in the tool, resulting from Bragg scattering at the array. This allows an additional stop band to be utilized at a further frequency.

[0015] Additional stop bands can also be created by designing the local resonators to have multiple resonant frequencies. Furthermore, the arrangement of the local resonators can be chosen to result in additional resonant frequencies for the array, either by using resonators with different relevant frequencies in the array or by creating additional stop bands through the shape of the array.

[0016] If the individual local resonators are tuned slightly differently, the stopband can be broadened around the first resonance frequency. However, this also results in a loss of sharpness, and the reduction of oscillations in this frequency range is less pronounced. However, these effects can be desirable. Furthermore, slightly different frequency tunings of the resonators can be useful to adapt the resonators to their position in the array of local resonators, for example, if additional forces are expected to act on certain areas of the array.

[0017] At least some of the local resonators can be designed as bending beam resonators. This consists of a beam, i.e. a generally cuboid-shaped body, which is clamped (fixed) at one end and whose other end can vibrate freely. This design has advantages in terms of the simplicity of its construction and the adjustability of its resonant frequency, which can be controlled by the dimensions of the beam and the support point. It should be noted that the beams do not necessarily have to be a classic, elongated beam, but generally a prism that is fixed at one side or point in such a way that it can vibrate. In particular, the resonator can also be designed as a plate that is machined from a surrounding material and connected to it at a corner.Another form of resonator that should be explicitly mentioned is a cross-shaped arrangement, which is coupled to the body to be damped in the center of the cross and has four oscillating masses at the ends of the cross arms. By choosing the shape of the resonators, the eigenmodes of the resonators' oscillation and their eigenfrequencies, and thus also the frequency range of the stop band created in the arrangement, can be determined. The shape of the individual resonators should not be limited to those described here, but can be selected according to the respective requirements. In particular, not all resonators in the arrangement of local resonators have to have the same shape, but can be adapted to the conditions of their respective position, as long as they have a largely consistent frequency tuning.

[0018] To attach the local resonators to an electronic component or support structure, they can be provided with a solder pin or solder pad. By using standardized connections, the resonator application can be easily integrated into conventional industrial manufacturing processes.

[0019] The local resonators can be applied directly to the electronic component to be damped. This allows for effective vibration reduction while saving space.

[0020] In particular, the local resonators can be formed integrally with the electronic component. This increases the design effort but can save additional space. Examples of such a one-piece design of the local resonators with the electronic component can be curved connecting pins that also function as cantilever resonators. Likewise, the array of local resonators can be machined from the wafer of a chip.

[0021] Instead, the arrangement of local resonators can also be arranged on a support structure for electronic components. This can have the advantage that the electronic component can be installed unchanged and is not exposed to any additional influences. Furthermore, the arrangement of local resonators can be designed such that it forms a stop band for vibrations in several electronic components arranged on a support structure. The arrangement of local resonators on the support structure of the electronic component can directly surround it in order to dampen mechanical vibrations in the component or to prevent vibrations from occurring in it. The arrangement can also be specifically designed at or around the points that couple the support structure to the environment in order to dampen the introduction of mechanical vibrations into the support structure and the electronic component.

[0022] The simplest example of such a support structure is a printed circuit board. In particular, the use of vibroacoustic metamaterials in the form of arrays of local resonators can eliminate the bending waves that arise at the connection points of printed circuit boards due to contact forces on rigid connections. Furthermore, by applying an array of local resonators to a conventional printed circuit board, the device for reducing mechanical vibrations can be easily integrated into existing manufacturing processes.

[0023] The array of local resonators can also be formed integrally with a circuit board, i.e., machined from the material of the circuit board. The previously described form of resonator is particularly suitable for this purpose; it involves individual plates machined from the material of the circuit board, which are connected to the remaining structure of the circuit board at a corner and thus supported in a vibrating manner. A special form in which the array of local resonators is part of the circuit board can be a sandwich-structure circuit board, in which the local resonators are machined from one of the inner layers of the circuit board. This design can save further installation space, as the surface of the circuit board is reserved for the electronic components to be arranged on it.

[0024] In another form, the array of local resonators can be attached to a housing of a device containing an electronic component. In this way, mechanical vibrations can be reduced throughout the entire structure. In particular, it may be useful to surround the points where a support structure of an electronic component is coupled to a housing with an array of local resonators to prevent the introduction of mechanical vibrations.

[0025] The electronic component can be a cable. In this case, the array of local resonators can be applied directly to the circumference of the cable. This allows the conduction of mechanical vibrations in the cable to be dampened.

[0026] The local resonators can also be integrated into heat sinks. This further reduces space requirements by combining the damping of mechanical vibrations with the additional effect of heat dissipation, which heat sinks are usually already designed for. To achieve this effect, the heat sinks or fins must be shaped to function as local resonators.

[0027] Another possibility is to incorporate at least some of the local resonators as active elements, for example, as miniaturized piezoelectric loudspeakers. This allows the natural frequency of the local resonators to be actively controlled, thus adapting the properties of the generated stop band(s) to specific, even temporary, conditions.

[0028] The described embodiments of the subject matter of the present application can be used both individually and in combination to achieve additional effects and to provide a device which is provided with an arrangement of local resonators for reducing mechanical vibrations in electronic components.

[0029] The above-mentioned and further aspects of the invention will become apparent from the detailed description of the embodiments given with the aid of the following drawings, of which:

[0030] Fig. 1 schematically shows a device for reducing mechanical vibrations on an electronic component, Fig. 2 shows another device for reducing mechanical vibrations on a printed circuit board, Fig. 3a shows a local resonator with soldering pins and Fig. 3b shows a local resonator with a soldering pad, Figs. 4a-4f show different possibilities for attaching an arrangement of local resonators on an electronic component or on a printed circuit board,

[0031] Fig. 5a is a perspective view of a printed circuit board from which an array of local resonators is machined, Fig. 5b is a plan view of the printed circuit board from Fig. 5a,

[0032] Fig. 6 shows a printed circuit board in sandwich structure with a middle layer provided with an array of local resonators,

[0033] Fig. 7a is a perspective view of a housing of an electronic component, and

[0034] Fig. 7b is a plan view of the housing of Fig. 7a, in which it can be seen that it is provided with arrays of local resonators, Figs. 8a-8c schematically show cables provided with arrays of local resonators,

[0035] Fig. 9a and 9b schematically show heat sinks in which local resonators are integrated, and

[0036] Fig. 10 schematically shows a chip with an integrated array of local resonators.

[0037] The claimed subject matter will be explained in more detail below based on the accompanying drawings. Like reference numerals refer to like elements.

[0038] Fig. 1 shows a simplified, schematic representation of a device for reducing mechanical vibrations on an electronic component 1. The electronic component can be, for example, a capacitor, a diode, a transistor, a sensor or an integrated circuit. The electronic component 1 is arranged on a printed circuit board 4. The printed circuit board 4 is only shown schematically; it could also be provided with other components, as well as connections and conductor tracks. The printed circuit board 4 can be made of an electrically insulating material, for example a fiber-reinforced plastic. The electronic component 1 is mechanically and conductively connected to the printed circuit board 4 via a plug-in or soldered connection. This very connection can be one of the weak points in the function of the electronic component 1 if it is exposed to mechanical vibrations.For example, fatigue fractures of solder joints can occur. To reduce the stress on the electronic component 1 caused by mechanical vibrations, it is provided with an array 2 of local resonators 3. The array 2 of local resonators 3 is applied directly to the electronic component 1. The local resonators are L-shaped bending beam resonators, with the short beam of the L connecting the longer beam to the surface of the electronic component 1. The array 2 comprises a number of local resonators 3 in a periodic pattern.

[0039] A similar structure is also shown in Fig. 2. This illustration shows a larger arrangement 2 of local resonators 3 designed as bending beam resonators, which are not mounted on an electronic component 1, but on a carrier plate 5, and via this are arranged directly on the printed circuit board 4. This can, for example, be the back of a printed circuit board 4, on the front of which an electronic component is arranged that is to be protected from mechanical vibrations. By arranging 2 of the local resonators 3 on the back of the printed circuit board 4, the entire installation space on the front of the printed circuit board 4 can be used for electronic components 1, so that no special layout is required here. It should also be noted that all illustrations of the present application show a printed circuit board 4.However, depending on the application, it may also be a different carrier structure for electronic components 1, whereby the concepts described can be easily transferred.

[0040] The arrangements of local resonators shown in Fig. 1 and Fig. 2 function in the same way: All local resonators 3 have approximately the same frequency tuning. The arrangement 2 of local resonators 3 thus forms a vibroacoustic metamaterial that exhibits negative effective mass properties in a frequency range around the resonant frequency of the local resonators 3. If the electronic component 1 or the circuit board 4 is excited to oscillate at this resonant frequency from the outside, or by the function of the electronic component 1, this oscillation is strongly damped, and the oscillation energy is absorbed in the local resonators 3. This creates a stop band, i.e., a frequency range in which wave propagation in the electronic component 1 and the circuit board 4 is suppressed. This greatly reduces mechanical oscillations acting on the electronic component 1.Since the local resonators can have multiple resonant frequencies depending on their design, multiple stop bands can also form around additional frequencies. These stop bands can cover different frequency ranges or overlap to create an enlarged stop band. Likewise, the individual local resonators can be designed with slightly different frequency tuning. This weakens the vibration reduction in the stop band range, but broadens it.

[0041] Fig. 3a and 3b show local resonators 3 in a cross-shaped design, each having four arms and cross beams at their ends. Since this design has additional eigenmodes, it can be used to attenuate additional frequency ranges. However, the functionality of this design of the local resonators 3 otherwise corresponds to the bending beam resonators from Fig. 1 and 2. Fig. 3a and 3b also show how the local resonators 3 can be arranged on a circuit board 4. In Fig. 3a, the local resonator 3 has solder pins 6 for this purpose. In Fig. 3b, the local resonator has solder pads 7. The local resonator 3 can be attached to a circuit board 4 like any other component using the solder pins 6 or the solder pads 7. Although the local resonators 3 can be soldered in place, this is primarily a mechanical connection, since the resonators 3 shown do not require an electrical connection.The situation would be different if active elements, such as piezo loudspeakers, were used as local resonators 3. In order to control these and thus adjust their natural frequency, solder pins 6 / solder pads 7 could also be designed for electrical connections. By using conventional fastening methods such as solder pins 6 or solder pads 7, the local resonators can be integrated into common printed circuit board manufacturing processes without great effort. For example, conventional assembly machines can be used to place the resonators 3, which can then be soldered on automatically. To ensure the formation of a stop band, the arrangement 2 of the local resonators 3 should be approximately periodic, and the distance between the local resonators 3 should be less than half a wavelength of a relevant frequency. Furthermore, the position of the arrangement 2 of local resonators 3 is also relevant.This is illustrated in Fig. 4a-4f. Fig. 4a serves as an overview and shows a printed circuit board 4 with an electronic component 1 mounted thereon. This corresponds to the illustration in Fig. 1 without an arrangement 2 of local resonators 3. Fig. 4b-4f show the same printed circuit board in plan view and show further possibilities for how arrangements 2 of local resonators 3 can be distributed on it to reduce mechanical vibrations on the electronic component 1. The arrangements 2 of local resonators 3 are shown here as hatched areas.

[0042] In Fig. 4b, the arrangement 2 of local resonators 3 is applied directly to the electronic component 1. This corresponds to the design shown in Fig. 1. This design dampens the relevant mechanical vibrations directly at the electronic component 1, and no additional installation space is required on the circuit board 4.

[0043] In Fig. 4c, the arrangement 2 surrounds the electronic component 1 on the circuit board 4, forming a stop band in the relevant frequency range. This allows for a larger-area arrangement 2.

[0044] Fig. 4d shows an embodiment in which the arrangement 2 is limited to areas around the connection points of the circuit board 4 and thus has a damping effect directly at the points where the majority of the mechanical vibrations are introduced into the circuit board 4.

[0045] Figs. 4e and 4f also show a plug connection 8 on the printed circuit board 4. Since mechanical vibrations can also be introduced into the system consisting of the printed circuit board 4 and the electronic component 1 via such plug connections 8, it may be useful to dampen them separately. In Fig. 4e, this is achieved by an arrangement 2 of local resonators 3 arranged between the plug connection 8 and the electronic component 1, thus suppressing the propagation of mechanical vibrations to the latter.

[0046] In Fig. 4f, the arrangement 2 of local resonators 3 is provided directly on the connector 8 in order to dampen the oscillations introduced here.

[0047] Of course, the application patterns shown in Fig. 4b-4f can also be combined with each other to protect the electronic component 1 from mechanical vibrations from different sources.

[0048] Fig. 5a and 5b show a printed circuit board 4 with integrated local resonators 3. In this illustration, the local resonators 3 are formed as one piece with the printed circuit board 4 and machined directly from it, for example by conventional drilling or milling. The individual resonators 3 consist of square plates that are connected to the surrounding printed circuit board 4 via a corner and are thus mounted so that they can vibrate. Recesses between the vibrating masses and the rest of the printed circuit board 4 can also be filled with an elastic damping mass. By exciting the local resonators 3 at their natural frequency, a stop band can in turn form in the printed circuit board 4. It should be noted that this embodiment is shown in a highly simplified manner in Fig. 5a and 5b, since the arrangement 2 of the local resonators 3 extends over the entire printed circuit board. However, this board is also intended to accommodate at least one electronic component 1.For this purpose, the deposition patterns shown in Fig. 4c-4d can be used for an actual implementation with integrated local resonators.

[0049] A further embodiment with integrated local resonators 3 is shown in Fig. 6. It is a printed circuit board 4 with a sandwich structure consisting of at least three layers. The middle layer 9 is provided with an arrangement 2 of local resonators 3 and corresponds in its function to the printed circuit board 4 shown in Figs. 5a and 5b. However, in this embodiment, the arrangement 2 of local resonators does not have to be limited to areas of the printed circuit board, since the two cover layers 10 serve to accommodate electronic components. Figs. 7a and 7b show a further embodiment in which the arrangement 2 of local resonators 3 is attached neither directly to the electronic component 1 nor to a printed circuit board 4, but to a housing 11. In this illustration, the housing 11 surrounds a printed circuit board 4 and an electronic component 1. However, the housing can also enclose other elements.It is also conceivable for the housing 11 to directly encapsulate an electronic component 1 without the component being arranged on a printed circuit board 4. The plan view in Fig. 7b shows that the area around the connection points at which the printed circuit board 4 is coupled to the housing 11 is provided with arrangements 2 of local resonators 3. This is particularly expedient since the connection between the housing 11 and the printed circuit board 4 is generally made via rigid connections, so that mechanical vibrations are transmitted to the electronic component 1 via these points. However, it could also be useful to provide other areas of the housing 11 with arrangements 2 of local resonators, for example if other components that generate vibrations are arranged in the housing.

[0050] Figs. 8a-8c illustrate how arrays 2 of local resonators 3 can also be attached to cables 12 to dampen the propagation of mechanical vibrations in them. In Fig. 8a, the local resonators are disk-shaped, with the edge of the disk forming the vibrating mass of the resonator. Fig. 8b shows a cross-section through this cable. In Fig. 8c, the circumference of the cable is provided with an array 2 of cantilever resonators 3. These arrays 2 of local resonators 3 can thus also create a stop band for the propagation of mechanical vibrations in the cable 12.

[0051] Fig. 9a and 9b show a heat sink 13 whose cooling fins 14 also function as local resonators 3. For this purpose, sections of the cooling fins 14 are designed in the form of cantilever resonators. Since the heat sink 13 comprises a plurality of these fins, an arrangement 2 of local resonators 3 can be easily realized. Since corresponding heat sinks are already provided in a variety of electronic systems, no additional installation space is required and no additional effort is incurred in design and assembly. Fig. 10 shows a miniaturized version of the concept. It shows a MEMS sensor 15 surrounded by an arrangement 2 of local resonators 3 machined directly from the wafer of the sensor chip.The arrangement 2 of local resonators 3 is thus formed in one piece with the electronic component 1 and the size of the local resonators 3 can be selected such that they form a stop band for mechanical wave propagation in a frequency range relevant for the MEMS sensor.

[0052] The described embodiments make it clear that the use of vibroacoustic metamaterials formed by arrays 2 of local resonators 3 provides a space-saving option with low design effort for reducing mechanical vibrations in an electronic component 1. It is also clear that there are numerous ways to apply such vibroacoustic metamaterials to electronic components 1, circuit boards 4, and housings 11 in such a way that a beneficial effect is achieved.

[0053] The embodiments shown here are therefore not limiting. In particular, these embodiments can be combined with one another to achieve additional effects. It will be obvious to those skilled in the art that modifications can be made to these embodiments without departing from the fundamental principles of the subject matter of this patent application, the scope of which is defined in the claims.

Claims

Patent claims 1. Device for reducing mechanical vibrations on an electronic component (1), comprising an arrangement (2) of local resonators (3) tuned to each have at least one natural frequency in a relevant frequency range, wherein the arrangement (2) of local resonators (3) is configured to generate at least one stopband for mechanical wave propagation in the electronic component (1) in the relevant frequency range.

2. Device according to claim 1, characterized in that the arrangement (2) of local resonators (3) is periodic.

3. Device according to one of the preceding claims, characterized in that the distance between the local resonators (3) is less than half a wavelength in a relevant frequency range.

4. Device according to one of the preceding claims, characterized in that individual local resonators (3) have a slightly different frequency tuning, so that the at least one stopband is broadened.

5. Device according to one of the preceding claims, characterized in that at least some of the local resonators (3) are designed as bending beam resonators.

6. Device according to one of the preceding claims, characterized in that the local resonators (3) are provided with a solder pin (6) or with a solder surface (7).

7. Device according to one of the preceding claims, characterized in that the arrangement of local resonators is mounted directly on the electronic component (1).

8. Device according to one of claims 1 to 5, characterized in that the arrangement (2) of local resonators (3) is formed integrally with the electronic component (1).

9. Device according to one of claims 1 to 5, characterized in that an arrangement (2) of local resonators (3) is arranged on a support structure for electronic components.

10. Device according to claim 9, characterized in that the support structure is a printed circuit board (4).

11. Device according to claim 10 characterized in that the arrangement (2) of local resonators (3) is formed integrally with the printed circuit board (4).

12. Device according to one of claims 1 to 5, characterized in that the arrangement (2) of local resonators (3) is mounted in a housing (11) of the electronic component (1).

13. Device according to one of claims 1 to 5, characterized in that the arrangement (2) of local resonators (3) is attached to a cable (12).

14. Device according to one of the preceding claims, characterized in that the local resonators (3) are integrated into heat sinks (13).

15. Device according to one of the preceding claims, characterized in that at least some of the local resonators (3) are designed as active elements.

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