DEVICE FOR MEASURING A PERSON'S VOCAL TRACT MOVEMENTS USING RADIO WAVES

Abstract

A device for measuring vocal tract movements of a person is disclosed. This device comprises at least one flexible support structure (180) designed to be adhered to a skin surface in the vocal tract region of the person. It also includes two ultra-wideband antennas (81, 86) oriented differently.

Description

TECHNICAL AREA The disclosure relates to a device for measuring a person's vocal tract movements, a system, and a patch. BACKGROUND An important form of communication occurs through speech, which in turn relies on functioning voice production. The vocal tract comprises the anatomical structures involved in the articulation of sounds and the production of phonation. It extends from the larynx to the lips. The vocal cords in the larynx are set into vibration by an airflow from the lungs. This process, also called phonation, generates acoustic waves, which are subsequently modulated in the supraglottal vocal tract, consisting of the pharynx, oral cavity, and nasal cavity. Diseases such as cancers of the larynx or pharynx can lead to permanent damage to the vocal tract and may necessitate the removal of the larynx (laryngectomy). This usually results in a partial or complete loss of voice. Several approaches are available to restore voice production, including electrolarynxes and shunt valves. However, these solutions often do not provide natural intonation, restrict freedom of movement, or require surgical intervention. Furthermore, using articulatory measurement modalities – e.g., ultrasound, electromyography, or radar – it is possible to recognize features of silent speech movements – for example, in people with complete or partial voice loss (voiceless speakers) or even speakers who voluntarily speak silently – using a machine-learned speech synthesis model and to convert these features into acoustic speech signals. Corresponding techniques are known, for example, from DE 10 2020 110 901 A1. A specific technique uses ultra-wideband radio waves to measure a person's vocal tract movements. See, for example, DE 10 2022 115 031 A1. However, it has been found that the reproducible application of suitable ultra-wideband antennas to a person's skin can be difficult. For example, a poorly attached ultra-wideband antenna can cause the measured signal to weaken. Interference can then overlay the actual signal in the corresponding measurement data stream, making reliable speech synthesis impossible or severely limited. Furthermore, it has been generally observed that conventional techniques for measuring vocal tract movements using ultra-wideband radio waves may have a limited signal level, or that the signal depicting the vocal tract movements may be superimposed by significant interference. SUMMARY Therefore, there is a need for a non-invasive, user-friendly solution to restore voice production in voiceless speakers, such as aphonic or dysphonic individuals. In the context of speech synthesis for voiceless speakers, there is a need for improved techniques for capturing measurement data streams based on ultra-wideband radio waves. Specifically, there is a need for improved techniques for measuring a person's vocal tract movements using ultra-wideband radio waves. There is a need for suitable measurement devices that allow for the reliable and reproducible placement of ultra-wideband antennas on the person's skin surface. There is a need for measurement devices that provide measurement data streams with improved signal levels. The tasks are solved by a device for measuring vocal tract movements of a person according to claim 1, a system according to claim 19 and a patch according to claim 21. The device for measuring (measuring device) vocal tract movements of a person comprises at least one flexible support structure. This support structure is designed to be adhered to the skin surface in the vocal tract region of the person. The device also includes a first ultra-wideband antenna (transmitting antenna) mounted on the at least one flexible support structure. The transmitting antenna is designed to emit radio waves toward the person's skin surface. Furthermore, the device includes a second ultra-wideband antenna (receiving antenna) mounted on the at least one flexible support structure. The receiving antenna is designed to detect second radio waves emanating from the skin surface. Finally, the device includes an electronic circuit designed to perform a radar measurement of the vocal tract movements based on a transmit signal for the transmitting antenna and a receive signal from the receiving antenna. The second radio waves can be generated by the interaction of the first radio waves with one or more structures of the vocal tract. The vocal tract acts as an acoustic filter, amplifying specific frequencies through resonance and playing a crucial role in sound production and modulation. Movements of the vocal tract, such as lip rounding, tongue positioning, mouth opening, and jaw movements, are essential for articulation. Thus, a spatial configuration of the vocal tract can be associated with an intended phoneme. Even in cases of larynx loss, the functions of the supraglottal vocal tract structures are often preserved, allowing vocal tract movements to persist and be detected non-invasively using radar technology. For example, the transmitting antenna can be configured to send signals at frequencies between 500 MHz and 2 GHz. The radar measurement can be implemented as a modulated continuous wave radar, also known as FMCW (Frequency Modulated Continuous Wave) radar. The transmitted signals can be continuous, with the frequency of the signals changing over time. A possible sweep rate is between 100 and 200 Hz. In other examples, pulsed signals can be used. The signals can also be of a constant frequency. The transmitting antenna can be positioned on the skin surface, such as in the cheek area, to direct the signals towards vocal tract structures, for example, towards the oral cavity. The transmitting and receiving antennas can each selectively transmit or receive radio waves with a specific orientation of the electromagnetic fields. In particular, the receiving antenna can be arranged relative to the transmitting antenna such that it selectively receives radio waves with a field that is largely orthogonal to the field of the radio waves emitted by the transmitting antenna. For example, it would be conceivable that the transmitting and receiving antennas could each selectively transmit or receive linearly polarized radio waves. The transmitting and receiving antennas can have the same structure or shape, but can be rotated e.g. by 90° ± 10° relative to each other, optionally by 90° ± 5°, and further optionally by 90° ± 2°. By using a transmitting antenna and a receiving antenna, each exhibiting selectivity for radio waves with a specific electromagnetic field orientation, mutual coupling—where the transmitted signal is detected as a received signal without interaction with the vocal tract—can be reduced. This will be explained in more detail below. The first radio waves emitted by the first transmitting antenna can interact with the vocal tract structures. This alters the field distribution of these first radio waves, resulting in the generation of second radio waves. Due to this change in field distribution, these second radio waves couple more strongly into the receiving antenna. In contrast, first radio waves traveling directly from the transmitting antenna to the receiving antenna do not couple into the receiving antenna, or only to a lesser extent, due to the near-orthogonality of their field distribution to that accepted by the receiving antenna. This near-orthogonality can be achieved, for example, by using linearly polarized antennas rotated 90° relative to each other. More generally, the antennas could be rotated relative to each other by 90° ± 10°, optionally further by 90° ± 5°, and optionally even further by 90° ± 2°. A linearly polarized antenna is an antenna that emits (or receives) electromagnetic waves whose electric field oscillates in a fixed direction in the far field and in a vacuum. This means that the polarization plane of the electric field remains constant in time and space (e.g., purely horizontal or vertical), instead of rotating or tilting (as with circularly or elliptically polarized antennas). The fields of two radio waves can be considered orthogonal or largely orthogonal to each other, for example, if the mutual coupling, which arises solely from the field interaction, does not exceed a level of 6 dB. The interaction of radio waves with the structures of the vocal tract can occur in various ways. For example, reflection, attenuation, or scattering can take place. Such interaction processes provide information about the spatial configuration of the vocal tract at a specific time. By acquiring a time-resolved data stream, the spatial configuration of the vocal tract can be observed over a specific period, allowing inferences to be made about vocal tract movements. Vocal tract movements can also be measured directly by observing frequency shifts (Doppler shifts). The electronic circuit can comprise one or more components. In particular, the electronic circuit can comprise one or more analog electronic components and / or one or more digital electronic components. The electronic circuit can, for example, include at least one amplifier for the transmit signal and / or for the receive signal. It can also include other high-frequency (HF) electronic components, such as a mixer. In an FMCW radar measurement, for example, a continuous, frequency-modulated HF signal is transmitted as the transmit signal using the transmitting antenna. In this example, the electronic circuit includes an HF signal generator that produces the transmit signal, the frequency of which is systematically increased or decreased over time. This transmit signal is amplified by an amplifier within the electronic circuit.The received signal from the receiving antenna is fed to a further RF amplifier in the electronic circuit. The amplified received signal is then mixed with a portion of the originally transmitted signal. This process takes place in a mixer within the electronic circuit, which generates the difference frequency between the transmitted and received signals. This difference frequency is directly proportional to the distance to the vocal tract structure. The resulting difference frequency is then filtered and digitized by appropriate components of the electronic circuit to enable measurement of the propagation delay and thus the distance to the vocal tract structure. In general, it is conceivable that one or more components of the electronic circuit are arranged close to the skin on the at least one flexible support structure. However, one or more other components of the electronic circuit can be arranged further away on a different circuit support structure, for example in a portable device. The at least one flexible support structure, together with the transmitting and receiving antennas, can form a patch. This means that an adhesive surface of the at least one flexible support structure can be applied to the skin surface, for example, on the cheek or neck. The at least one flexible support structure can be made of a skin-compatible material, such as a textile. The at least one flexible support structure can have one or more layers. For example, an adhesive layer could be applied to a supporting layer, with the supporting layer typically being thicker than the adhesive layer. The at least one flexible support structure can, for example, consist of a substrate layer and an adhesive layer. The substrate layer can be made of plastic (especially a plastic film) or a textile.Functional structures such as ultra-wideband antennas and their connectors can be arranged on the substrate layer. In some examples, the ultra-wideband antennas can be printed onto the flexible support structure. The adhesive layer can be configured to attach the at least one flexible support structure to the skin, for example, on a person's face. For instance, the at least one flexible support structure can be attached to a cheek or the neck area of ​​the person. The adhesive can be a biocompatible glue. In some examples, the at least one flexible support structure may comprise a first flexible support structure and a second flexible support structure separate from the first. The transmitting antenna may, for example, be mounted on the first flexible support structure. The receiving antenna may, for example, be mounted on the second flexible support structure. In other words, the two flexible support structures may form two patches that are applied separately to measure the vocal tract. In some examples, the first flexible support structure may be positioned on one cheek and the second flexible support structure on the other cheek of the person. In such a configuration, mutual coupling can be further reduced by spatially separating the transmitting and receiving antennas. The device can, for example, include one or more alignment markers on the first and second flexible support structures. The alignment markers (e.g., arrows or symbols indicating an orientation of the flexible support structure) can indicate an orientation for adhering the first flexible support structure with the transmitting antenna and the second flexible support structure with the receiving antenna to the skin surface. This nominal orientation of the transmitting antenna relative to the receiving antenna, indicated by the alignment markers, is adjusted such that the electromagnetic field with which the transmitting antenna sends the signal is largely orthogonal to the field of the received signal picked up by the receiving antenna. In some examples, by aligning the first and second flexible support structures using the alignment markers, the transmitting and receiving antennas can be positioned such that the field of the first radio waves emitted by the transmitting antenna and the field of the second radio waves accepted by the receiving antenna are largely orthogonal to each other. For example, a polarization direction of the radio waves emitted by the transmitting antenna could form an angle in the range of 40° to 50° or 80° to 100° with a polarization direction of the radio waves detected by the receiving antenna (for example, measured in the far field and in a vacuum). This can reduce mutual coupling.At the same time, it can be ensured that, in typical interaction processes of radio waves at the vocal tract structures, the transmitted signal is received by the receiving antenna with a significant signal level. In some examples, the device may include a further or third ultra-wideband antenna, which may be arranged on the first flexible support structure. The third ultra-wideband antenna may be configured to transmit third radio waves towards the person's skin surface (additional transmitting antenna). These third radio waves can have a field that is largely orthogonal to the field of the first radio waves. For example, the transmitting antenna and the second transmitting antenna can be arranged on the first flexible support structure such that a polarization direction of the first radio waves emitted by the transmitting antenna (measured, for example, in the far field and in a vacuum) forms an angle in the range of 85° to 95° with a polarization direction of the third radio waves emitted by the second transmitting antenna. In other words, the transmitting antenna and the second transmitting antenna can be substantially orthogonal to each other. The described alignment of the transmitting antenna relative to the second transmitting antenna results in the receiving antenna being positioned such that the field of the third radio waves emitted by the second transmitting antenna overlaps the field received by the receiving antenna at an angle of, for example, 40° to 50°. The use of two transmitting ultra-wideband antennas can increase the efficiency of signal transmission and improve the signal coverage of the area under investigation. In principle, when aligning one or more transmitting antennas with respect to the receiving antenna, other angles of the respective fields are also possible. In preferred examples, the transmitting antenna and / or the additional transmitting antenna and the receiving antenna are arranged such that the field of radio waves emitted by the transmitting antenna and / or additional transmitting antenna does not correspond to a field of radio waves received by the receiving antenna. In this way, the mutual coupling from the transmitting channel to the receiving channel is reduced. The alignment of the transmitting antenna with respect to the receiving antenna can be specified by alignment markers when separate carrier substrates are used. If multiple transmitting antennas are present, as described above, they can be operated alternately. In some examples, the device for this purpose may include an RF switch. The RF switch may be located close to the antenna. For example, the RF switch may be mounted on a first circuit carrier structure. The RF switch may be configured to selectively direct a transmit signal applied to one input of the RF switch, depending on a control signal, either to the transmitting antenna or to another transmitting antenna. The RF switch may, for example, include diodes, transistors, or MEMS (microelectromechanical systems). Switching between the transmitting antenna and the other transmitting antenna can thus be achieved using time-division multiplexing. Furthermore, the device can include a signal splitter. This splitter can be positioned close to the skin. It can be located on the first circuit support structure. The signal splitter can, for example, be configured to split an input signal supplied by a cable into a power signal for operating the high-frequency switch, the control signal for the high-frequency switch, and the transmit signal. In this way, a power source for supplying the power signal can be located far from the skin, and the power signal, superimposed with the transmit signal, can be transmitted via the cable from the remote position to the near-skin position. By positioning the power source far from the skin, the part of the measuring device closest to the skin is lighter and more compact.By using a single cable for both transmitting the signal and transmitting the supply signal, connecting the part of the measuring device furthest from the skin to the part closest to the skin can be made easier. The use of the first circuit carrier structure in combination with the flexible support structure thus enables a multi-part construction of the measuring device in close proximity to the skin. The patch can be formed by the flexible support structure, and a housing containing the first circuit carrier structure can then be placed on the patch. The first circuit support structure can be rigid or substantially rigid. In some examples, the circuit support structure may consist of multiple layers. For instance, the first circuit support structure may be a printed circuit board (PCB). In some examples, the first circuit support structure is enclosed in a housing. The rigid design of the first circuit support structure enables the protected and robust arrangement of certain components of the electronic circuit, particularly RF components, and a corresponding RF circuit. In particular, compared to implementations where such components are mounted directly on the flexible support structure, a more robust and durable design can be achieved. In some examples, an amplifier may be provided on the first circuit carrier structure to amplify the transmit signal applied to one input side of the high-frequency switch. For example, this could correspond to the amplifier for the transmit signal of the electronic circuit. However, it could also be an additional amplifier. The device may further comprise a first connecting element, which may be configured to electrically contact and mechanically fix the transmitting antennas arranged on the first flexible support structure to the high-frequency switch arranged on the first circuit support structure. The first connecting element may, for example, comprise one or more spring-loaded contact pins. A housing accommodating the first circuit support structure can be placed onto the surface formed by the first flexible support structure by means of the first connecting element. The measuring device (or, in particular, the electronic circuit) may include an amplifier mounted on a second circuit support structure. In some examples, the amplifier may be configured to amplify the received signal. The second circuit support structure can be dimensionally stable or substantially dimensionally stable. In some examples, the circuit support structure can consist of multiple layers. For example, the second circuit support structure can be a printed circuit board. In some examples, the second circuit support structure is enclosed in a housing. The second circuit carrier structure can essentially correspond to the first. While the first circuit carrier structure is assigned to the transmitting antenna and, if applicable, to a second transmitting antenna, the second circuit carrier structure is assigned to the receiving antenna. Both the first and second circuit carrier structures are therefore located close to the surface. It is possible for cables to connect a part of the measuring device located further away from the surface to both the first and second circuit carrier structures. For example, the device may further include a second connecting element. This second connecting element may be configured to electrically contact and mechanically fix the ultra-wideband antenna, mounted on the second flexible support structure, to the amplifier, which is mounted on the second circuit support structure. The device may, for example, be configured to couple the received signal from the receiving antenna into the amplifier via the second connecting element. The second connecting element can, for example, comprise one or more spring contact pins. In other examples, the second connecting element can also be a cable connector. The preceding scenario described a first patch formed by the first flexible support structure, carrying one or two transmitting antennas. A second patch formed by the second flexible support structure carries the receiving antenna. Each patch can be connected to a corresponding circuit support structure via a connecting element. One or more analog RF components are mounted on these circuit support structures, processing the transmitting and receiving signals in close proximity. In addition to such close-coupled RF components, various examples also include one or more other electronic components located further away. For example, the RF signal generator could be located further away; a mixer could also be located further away. For this purpose, another circuit support structure is provided, which can be housed in a suitable enclosure or device. In some examples, the device can therefore include an additional circuit support structure, which is connected to the first and second circuit support structures via high-frequency cables and on which the electronic circuitry can be arranged. This additional support structure can carry components of the measuring device that are not directly connected to the skin. The additional circuit carrier structure can, for example, be enclosed in a housing. For example, the additional circuit carrier structure can be designed to be worn on the body. For this purpose, a clamp and / or other fastening device can be attached to the housing. For example, the housing can be designed so that the additional circuit carrier structure can be carried on a belt, around the neck, or as a backpack. The housing can be designed as a "neck-wearable" device, i.e., a device worn around the neck. In some examples, certain components of the electronic circuit can be located on the outermost circuit support structure, i.e., farther away from the surface. As described previously, however, it is also possible that, for example, amplifiers for the transmit and / or receive signal are located on the first or second circuit support structure, i.e., close to the surface. The preceding examples described in particular where the transmitting antenna, and optionally a second transmitting antenna, are arranged at a first skin-adjacent position on a first flexible support structure; and the receiving antenna is arranged at a second skin-adjacent position on a second flexible support structure (which can be positioned separately from the first flexible support structure). Thus, for example, several patches can be provided, applied to different areas of the skin surface. However, such a spatial separation of the one or more transmitting antennas from the receiving antenna is only one variant, and another variant is explained below. In some examples, the transmitting and receiving antennas can be arranged on the same flexible support structure. This means that only one flexible support structure is needed, further improving patient mobility. A single patch is applied to the skin surface. At the same time, the spatial separation between the transmitting and receiving antennas is reduced compared to the previously described example, which uses two separate flexible support structures. This reduced spatial separation tends to result in increased mutual coupling. To nevertheless reduce this mutual coupling, the selectivity of the receiving antenna for a specific field, field distribution, or field orientation can be exploited. This will be explained below. For example, the transmitting and receiving antennas can be arranged on the same flexible support structure such that the field of the first radio waves emitted by the transmitting antenna forms an angle in the range of 85° to 95° with the field of the second radio waves received by the receiving antenna. In a preferred example, the transmitting and receiving antennas can be arranged on the same flexible support structure such that these fields are orthogonal to each other. By appropriate alignment, mutual coupling can be reduced. The attenuation due to the different fields or field orthogonality can be 6dB or more. In some examples, the device may further include a third circuit support structure on which one or more electronic circuit components and a battery contact may be arranged. This third circuit support structure may also be dimensionally stable, for example, as a circuit board. In some examples, the third circuit support structure may be enclosed in a housing. The third circuit support structure may be positioned close to the skin. This means that the third circuit support structure is located at a distance from the transmitting and receiving antennas, which are positioned close to the skin. The third circuit carrier structure can support one or more components of the electronic circuit, such as an RF amplifier, but also, in some examples, an RF signal generator and / or an analog-to-digital converter. This third circuit carrier structure is connected to another circuit carrier structure, for example, via a cable or a wireless communication link. If a cable connection is used, the generation of the RF signal for radar measurement takes place on the other circuit carrier structure; the analog-to-digital conversion can also occur on this structure. Amplifiers can then be located on the third circuit carrier structure. If a wireless communication link is used, the RF signal generator can be located on the third circuit carrier structure; the analog-to-digital conversion also takes place on this structure.In this case, a battery contact may also be present on the third circuit carrier structure, which is closest to the skin. The battery contact is designed to accommodate a (e.g., rechargeable) battery that provides a power supply signal for the electronic circuitry and, in particular, the RF signal generator. Furthermore, the device may include a third connecting element, which may be configured to establish electrical contact between one or more components arranged on the third circuit support structure and the transmitting and receiving antennas. The third connecting element may, for example, include at least one magnet for mechanical fixation and at least one spring contact pin and / or at least one contact surface for electrical contact. In some examples, the spring contact pins may be arranged on the circuit support structure, and the flexible support structure may have contact surfaces for the spring contact pins. However, it is also possible for the spring contact pins to be arranged on the flexible support structure, and for the circuit support structure to have the contact surfaces.In other examples, the flexible support structure as well as the circuit support structure can have both spring contact pins and contact surfaces for spring contact pins. In some examples, the transmitting and receiving antennas each have a bow-tie geometry with two antenna arms. It is possible for one feed point of the transmitting antenna to be located between the two antenna arms of the receiving antenna within the bow-tie geometry. This allows for a particularly space-saving integration of the transmitting and receiving antennas. The device may further include a communication interface, which can be configured to transmit digital measurement data from the radar measurement generated by the electronic circuitry—obtained, for example, from an analog-to-digital converter—to another communication interface. For example, the communication interface may be provided by a cable, such as a coaxial cable. In some examples, the communication interface may be a wireless communication interface, which can be configured to wirelessly transmit digital measurement data from the radar measurement generated by the electronic circuitry to another wireless communication interface. This can be done, for example, via Wi-Fi or Bluetooth. The system comprises the device, a processor, and memory. The processor is configured to load and execute program code from memory and to generate a voice signal associated with vocal tract movements based on digital radar measurement data. Evaluation can be performed, for example, using a machine-learned speech synthesis model. Corresponding techniques are known, for example, from US 2023 O 154 450 A1. Various speech synthesis models are generally known in the prior art, which can be flexibly combined with the measurement techniques disclosed herein. However, the specific processing of the measurement data streams acquired by the measuring devices and methods described herein is not crucial, and the techniques described herein can be combined with different data processing methods. This voice signal can be output via at least one loudspeaker, with the output occurring in real time or near real time. The latency can range from several tens to several hundred milliseconds. The loudspeaker could, for example, be located far away from the skin. The system can also include a communication interface, with the processor configured to receive the digital measurement data from the radar measurement via this interface. The communication interface can be, for example, either wired or wireless. The patch for measuring a person's vocal tract movements comprises at least one flexible carrier structure designed to be adhered to a skin surface in the vocal tract region. The patch further comprises at least one ultra-wideband antenna mounted on the at least one flexible carrier structure, as well as a connecting element. The connecting element is designed to provide electrical contact for the at least one ultra-wideband antenna and to provide a releasable mechanical fixation of an enclosed circuit carrier structure to the at least one flexible carrier structure. The releasable mechanical fixation may, for example, include a magnetic connection. The electrical contact may, for example, include at least one spring-loaded contact pin and / or at least one contact surface.In particular, the electrical contact can comprise two spring contact pins and two contact surfaces. The at least one flexible support structure can, for example, correspond to the first, second, or the same flexible support structure. The connecting element can, for example, be the first, second, or third connecting element. The housed circuit support structure can, for example, correspond to the first, second, or third circuit support structure. The features set out above and those described below can be used not only in the corresponding explicitly set out combinations, but also in further combinations or in isolation, without leaving the scope of protection of the present invention. BRIEF DESCRIPTION OF THE FIGURES Fig. 1 schematically shows an example of a system comprising a device for measuring a person's vocal tract movements, a processor, and a memory. Fig. 2 schematically shows an exemplary embodiment of the system comprising the device for measuring a person's vocal tract movements, the processor, and the memory. Fig. 3A schematically shows another exemplary embodiment of the system comprising the device for measuring a person's vocal tract movements, the processor, and the memory. Fig. 3B schematically shows another exemplary embodiment of the system comprising the device for measuring a person's vocal tract movements, the processor, and the memory. Fig. 4 shows an example of an arrangement of two ultra-wideband antennas. Fig. 5A and Fig. 5B show an example of a patch for measuring a person's vocal tract movements. DETAILED DESCRIPTION Several embodiments are described in detail below with reference to the accompanying drawings. It should be noted that the description of these embodiments is not intended to be limiting. The scope of application is not restricted by either the described embodiments or the merely illustrative drawings. Expert readers will recognize that various alternative and / or equivalent embodiments can be chosen as replacements for the specific embodiments presented here without departing from the scope of the invention. The aim of this application is to cover all adaptations and variations of the embodiments described herein, so that the invention is limited only by the claims and their equivalents. The drawings are to be considered schematic representations, whereby the elements illustrated therein are not necessarily depicted to scale. Rather, the individual elements are shown in such a way that their function is immediately recognizable to a person skilled in the art. The same reference symbols are used throughout the illustrations and the description to denote identical features or components. The following describes implementations for a measuring device that can perform radar measurements of vocal tract movements. Based on a corresponding measurement data stream, a machine-learned speech synthesis model can then generate a synthetic speech signal. Synthetic speech can also be achieved for voiceless speakers in this way. Several of the measuring devices described herein can be designed with multiple components. In particular, one or more parts of the measuring devices can be positioned close to the skin, while one or more other parts are positioned further away. For example, a portable control unit located further away from the skin can include digital electronics, in particular an electronic data processing device that determines the measurement data stream based on measurement signals and uses the measurement data stream for inference of the machine-learned speech synthesis model. The generation of RF signals can take place in an RF signal generator located in the portable control unit located further away from the skin. These RF signals can then be transmitted via a cable connection to a position closer to the skin, where the RF signals are amplified. The transmitted signals thus obtained can then be fed into a transmitting antenna that is attached to the skin via an adhesive patch.A corresponding RF amplifier is typically not mounted directly onto the flexible support structure of the patch, but rather onto a separate circuit support structure enclosed in a housing. This separate circuit support structure is connected to the transmitting antenna via an electromechanical connection. Implementations are conceivable in which the transmitting and receiving antennas are formed on a common flexible support structure or patch. In such a scenario, the same circuit support structure carrying the RF amplifier discussed above can also carry a further RF amplifier for amplifying the received signal picked up by the receiving antenna; the amplified received signal can then be transmitted via the cable connection to the remote portable control unit.However, the amplified received signal could also be mixed with the transmit clock signal on the circuit carrier structure located close to the skin. In another implementation variant, two separate patches are used, meaning two separate flexible support structures. Then the transmitting and receiving antennas can be positioned separately, for example, on opposite sides of the vocal tract. A corresponding, skin-adjacent circuit carrier structure can be provided for each of these two flexible support structures, which is connected to the respective antenna via an appropriate electromechanical connection. In this case, the mixing of the transmitting and receiving signals can take place further away from the skin. From the description above, it is evident that the multi-part nature of the measuring devices can be defined at different hierarchical levels. First, the measuring device can be multi-part with respect to one or more skin-contact parts and one or more remote parts. Second, the skin-contact parts themselves can be multi-part. The latter has the particular advantage that active RF components are arranged on a separate circuit carrier structure housed in a suitable enclosure, while the transmitting and receiving antennas are arranged on patches connectable to this separate circuit carrier structure or structures. These patches are disposable parts, meaning they are replaced regularly due to skin contact. On the other hand, the skin-contact circuit carrier structure can be reused, i.e., it consists of reusable parts.This describes electro-mechanical connecting elements that, through a magnetic contact, enable particularly easy attachment of the skin-close circuit carrier structure to the respective plaster. It is understood that the field orientation mentioned in the examples, with a relative offset of 80° to 90°, represents only one possible realization of the largely orthogonal electromagnetic fields of the transmitting and receiving antennas. Fig. 1 schematically shows an example of a system 30 comprising a device 31 for measuring vocal tract movements of a person, which has a first ultra-wideband antenna or transmitting antenna 81, a second ultra-wideband antenna or receiving antenna 86, and an electronic circuit 71. The system 30 also includes an electronic data processing device 69 with a processor 61 and a memory 62. The device is designed to be adhered to a skin surface in the vocal tract region of the person. While the electronic data processing device 69 is typically located far from the skin, at least some components of the electronic circuit 71 can be located close to the skin. The transmitting antenna 81 is configured to send initial radio waves towards the person's skin surface. The receiving antenna 86 is configured to receive or detect secondary radio waves emanating from the skin surface. The first radio waves can, for example, be linearly polarized in the far field and in a vacuum or in air, and exhibit a first polarization direction. The second radio waves can, for example, be linearly polarized in the far field and in a vacuum or in air, and exhibit a first polarization direction. However, the presence of tissue and the limited distance between transmitting antenna 81 and receiving antenna 86 also make near-field effects significant. As a result, linearly polarized radio waves are typically no longer present (in the near field, the electric and magnetic fields are not necessarily oriented perpendicular to each other); however, the fields can still be orthogonal to each other, for example, due to their overall spatial distribution and / or the observed modes. The electronic circuit 71 is configured to perform radar measurements of vocal tract movements based on a transmitted signal for the transmitting antenna 81 and a received signal from the second receiving antenna 86. For this purpose, the electronic circuit 71 comprises one or more components, such as an RF signal generator, one or more RF amplifiers, an analog-to-digital converter, a mixer, etc. The electronic circuit 71 may also include control electronics for controlling operating modes, frequencies, and / or signal processing. Furthermore, the electronic circuit may provide an operating voltage or supply signal for other components, particularly RF components. Processor 61 is configured to load and execute program code from memory 62 and to generate a voice signal associated with the movements of the vocal tract based on digital measurement data or data streams from the radar measurement. For this purpose, Processor 61 can apply a speech synthesis model to the measurement data. Fig. 2 schematically shows an exemplary embodiment of the system 30. A first flexible support structure 80, located close to the skin, and a second flexible support structure 85, also located close to the skin and separate from the first flexible support structure 80, are shown. The transmitting antenna 81 is mounted on the first flexible support structure 80, and the receiving antenna 86 is mounted on the second flexible support structure. The flexible support structures 80, 85 can, for example, consist of a substrate layer and an adhesive layer. The substrate layer can be made of, for example, plastic or textiles. The adhesive layer can be designed to attach the flexible support structures 80, 85 to a person's skin as a patch. The adhesive can be a biocompatible adhesive. As shown in Fig. 2, for example, the first flexible support structure 80 can be attached to one cheek and the second flexible support structure 85 to the other cheek of the person. In the example shown in Fig. 2, the measuring device 31 further includes a third ultra-wideband antenna 82 (this is, however, generally optional), which can also be mounted on the first flexible support structure 80. The third ultra-wideband antenna 82 can be configured to selectively transmit third radio waves towards the skin surface of the person. The third ultra-wideband antenna 82 can therefore be configured as an additional transmitting antenna. However, the third ultra-wideband antenna 82 could also be configured as an additional receiving antenna. For the sake of simplicity, it will be assumed in the following description that the third ultra-wideband antenna 82 is an additional transmitting antenna 82. For example, the transmitting antenna 81 and the second transmitting antenna 82 can be arranged on the first flexible support structure 80 such that the field orientation 91 of the radio waves emitted by the transmitting antenna 81 forms an angle in the range of 85° to 95° with the field orientation 92 of the radio waves emitted by the second transmitting antenna 82. In principle, all other angles are also possible when aligning the transmitting antennas. The field orientations 91, 92 can, for example, correspond to polarization directions in the far field and in a vacuum. Otherwise, they can indicate preferred directions or certain dominant directions of the electric or magnetic field of the electromagnetic waves. To control the transmitting antennas 81, 82, the device can include a high-frequency switch 72, which can be arranged on a first circuit support structure 83 located close to the skin. The high-frequency switch 72 can be configured to selectively supply a transmit signal applied to an input side of the high-frequency switch to either the first ultra-wideband antenna 81 or the third ultra-wideband antenna 82, depending on a control signal. In the illustrated example, an RF amplifier 73 is arranged on the first circuit carrier structure 73, which amplifies the transmit signal applied to one input side of the high-frequency switch 72. For example, this could correspond to the amplifier for the transmit signal of the electronic circuit. However, it could also be an additional amplifier. For example, transmitting antenna 81 and / or transmitting antenna 82 can emit radio waves into the person's oral cavity. In this way, they can interact with structures of the vocal tract, for example. After this interaction, the radio waves can then form the received signal and be picked up by the receiving antenna 86. The device can, for example, include one or more alignment markers 84, 89 on the first flexible carrier structure 80 and the second flexible carrier structure 85. The alignment markers 84, 89 can indicate an orientation for adhering the first flexible carrier structure 80 and the second flexible carrier structure 85 to the skin surface. As shown in Fig. 2, the alignment markers can be arrows. However, other symbols and / or color markings are also conceivable, which would assist a user in aligning the flexible carrier structures on the skin. In some examples, when aligning the first flexible support structure 80 and the second flexible support structure 85 using the alignment markers 84, 89, the transmitting antenna 81 and / or the transmitting antenna 82 and the receiving antenna 86 can be arranged relative to each other such that a field orientation 91, 92 of the radio waves emitted by the transmitting antennas 81 and / or the transmitting antenna 82 forms an angle in the range of 40° to 50° with a field orientation 96 of the radio waves received by the receiving antenna 86. Such an alignment of the field orientations 91, 92, 96 has proven to be particularly advantageous for the signal level ratio with respect to interference, especially mutual coupling. However, in principle, all other angles are also possible when aligning the ultra-wideband antennas. In addition to the first circuit carrier structure 83, the measuring device 31 also has a second circuit carrier structure 87 located close to the first. An amplifier 79, configured to amplify the received signal, can be arranged on the second circuit carrier structure 87. The amplifier 79 can, for example, correspond to the amplifier for the received signal of the electronic circuit 71. In some examples, however, the amplifier can also be an additional amplifier. The circuit support structures 83, 87 can be dimensionally stable or substantially dimensionally stable. For example, the circuit support structures 83, 87 can be circuit boards. In some embodiments, the circuit support structures 83, 87 can be enclosed in a housing. This allows, in particular, RF components arranged on the circuit support structures 83, 87 to be protected against environmental influences. A signal splitter (not shown in Fig. 2) can be arranged on the circuit carrier structure 83, which is configured to split an input signal provided by a cable 77 into a supply signal for operating the RF switch 72, the control signal of the RF switch and the transmit signal. Furthermore, the device can have a first connecting element 75, which can be configured to electrically contact and mechanically fix the transmitting antennas 81, 82 arranged on the first flexible support structure 80 to the RF switch 72 arranged on the first circuit support structure 83. The first connecting element 75 can, for example, comprise one or more spring contact pins. In other examples, the first connecting element 75 can also be a cable connector. Furthermore, the measuring device 31 can include a second connecting element 76, which can be configured to electrically contact and mechanically fix the receiving antenna 86, arranged on the second flexible support structure 85, to the amplifier 79, arranged on the second circuit support structure 87. The device can, for example, be configured to couple the received signal from the receiving antenna 86 into the amplifier 79 via the second connecting element 76. The second connecting element 76 can, for example, include one or more spring-loaded contact pins. In other examples, the second connecting element 76 can also be a cable connector. The measuring device 31 also includes a further circuit carrier structure 60, which is connected to the first circuit carrier structure 83 and the second circuit carrier structure 87 via cables 77, 78, and on which further components 79 of the electronic circuit 71 are arranged. The further components 79 can, for example, include an RF signal generator configured to inject a transmit signal into cable 77. The further components 79 can include a mixer configured to mix transmitted signals with received signals received via cable 78. Furthermore, the components 79 can include an analog-to-digital converter that converts an output of the mixer. For example, the additional circuit carrier structure 60, together with the electronic data processing device 69, can be arranged remotely. The electronic data processing device 69 can also be coupled to a loudspeaker. Synthetic speech could be output via this loudspeaker. The components 60 and 69 can, for example, be housed in a neck wearable. Fig. 3A schematically shows another exemplary embodiment in which the transmitting antenna 81 and the receiving antenna 86 are arranged on the same flexible support structure 180. For example, the transmitting antenna 81 and the receiving antenna 86 can be arranged on the same flexible support structure 180 such that a field orientation 191 of the radio waves emitted by the transmitting antenna 81 encloses an angle in the range of 85° - 95° to a field orientation 192 of the radio waves detected by the receiving antenna 86. The flexible support structure 180 is connected to a circuit support structure 183 via a connecting element 176. The circuit support structure 183 carries one or more components of the electronic circuit 71 implementing the radar measurement: in the example shown, these are in particular an RF amplifier and further RF components 179, such as an RF mixer. Further RF components 179.1 are arranged on the further circuit support structure 60, as in the example of Fig. 2. The circuit support structure 60 is connected to the circuit support structure 183 via a cable 178. In the example of Fig. 3A, however, the RF switch 72 is not required, since only a single transmitting antenna 81 is used. The mixer could also be arranged as a further RF component 179.1 on the further circuit support structure 60. Figure 3B shows a variant of Figure 3A in which all components of the electronic circuit are arranged on the circuit carrier structure 183; a wireless communication interface 175.1 is also provided there. The wireless communication interface 175.1 establishes a wireless communication connection 175.3 with another wireless communication interface 175.2, which is controlled by the processor 61 of the electronic data processing device 69. Thus, the generation of the high frequency and the analog-to-digital conversion take place close to the device – in contrast to the scenario in Figure 3A. Furthermore, in the scenario of Figure 3B, a battery 179 is provided in a corresponding battery contact arranged on the circuit carrier structure 183. In this way, a supply signal is provided for the electronic circuit 71 and the wireless communication interface 175.1. In the example of Figure 3B, the battery 179 is located in a corresponding battery contact arranged on the circuit carrier structure 183.3A can provide the supply signal via the cable (as a DC component). For example, the transmitting antenna 81 and the receiving antenna 86 can each have a bow-tie geometry with two antenna arms, as shown schematically in Fig. 4. Both antennas 81 and 86 have, for example, the same geometry but are rotated approximately 90° relative to each other. As a result, the transmitting antenna 81 transmits radio waves with a field that is largely orthogonal to the field of the radio waves received by the receiving antenna 86. It is possible for a feed point of the first ultra-wideband antenna 81 to be located between the two antenna arms of the second ultra-wideband antenna 86 in a bow-tie geometry. This orientation reduces direct coupling of the radio waves emitted by the transmitting antenna 81 into the receiving antenna 86. Due to their arrangement on the same flexible support structure 180 and the resulting spatial proximity, the received signals can exhibit a higher amplitude compared to a configuration using multiple, for example, two flexible support structures. The signal-to-noise ratio can also be improved. Fig. 5A shows a possible embodiment of a patch 500 for measuring vocal tract movements of a person. The patch 500 comprises at least one flexible carrier structure 580 (which, for example, implements one or more of the carrier structures 80, 85, 180) designed to be adhered to a skin surface in the vocal tract region of the person. Furthermore, the patch 500 comprises at least one ultra-wideband antenna: In the example of Fig. 5A, the transmitting antenna 81 and the receiving antenna 86 are arranged on the at least one flexible carrier structure 580. In the example shown, the transmitting antenna 81 and the receiving antenna 86 are arranged in a bow-tie geometry. However, other arrangements are also possible. The connecting element 576 is designed to provide a releasable mechanical fixation of a housing 515 (in which a circuit carrier structure, not visible in Fig. 5A, is arranged) to the flexible support structure 580. In the example of Fig. 5A, the connecting element 576 has an annular ferromagnetic contact surface 577 projecting from a surface of the flexible support structure 580. This surface can exert a magnetic attraction on permanent magnets 577.1, which are provided on the underside of the housing 516. For electrical contact, the connecting element has guide holes 578 into which spring contact pins 578.1 can engage; the RF signals are conducted via the spring contact pins 578.1 between corresponding RF components on the circuit carrier structure arranged in the housing 515 and the feed points of the antennas 81, 86. These guide holes 578 are shown in Fig.5B is particularly easy to identify; it exposes a contact surface for the spring contact pins and couples these to the feed points of the antennas 81, 86. Furthermore, a recess 516 is provided in the housing 515 through which a cable can be routed (see cables 77, 78, 178). The housing 515 can, for example, protect internal components against environmental influences such as splashing water, perspiration, etc. In this way, the housing 515, together with the internal components, can be used as a reusable component and successively mounted on different patches 500. Typically, the patches 500 are changed every day or even several times a day. Figures 5A and 5B show that the contact surface 577 extends in a plane. This plane of the contact surface 577 is parallel to, but offset from, an antenna plane in which the transmitting antenna 81 and the receiving antenna 86 extend. Accordingly, the permanent magnets 577.1 are set back relative to the spring contact pins 578.1 on the underside of the housing 515. This results in the contact surface 577 forming a circumferential collar that surrounds the area of ​​electrical contact and shields it from environmental influences. This ensures a reliable electrical contact because, for example, the ingress of liquid into this interior space, which is surrounded by the collar-like structure of the contact surface 577, is prevented. Naturally, the features of the embodiments and aspects of the invention described above can be combined with one another. In particular, the features can be used not only in the combinations described, but also in other combinations or individually, without leaving the scope of the invention. For example, techniques have been described above in which a flexible support structure carries a transmitting antenna and a receiving antenna, particularly in a bow-tie geometry. Alternatively or additionally to such integration of a transmitting antenna and a receiving antenna on a common flexible support structure, it would also be conceivable to integrate, for example, two transmitting antennas or two receiving antennas on a corresponding flexible support structure. In particular, it would be conceivable, for example, in the scenario described in Fig. 2, that two transmitting antennas are used on one flexible support structure and, in addition, two receiving antennas are used on the other flexible support structure.In such a scenario, a first transmitting antenna can be activated during the first timeslot; during the same timeslot, the first receiving antenna and the second receiving antenna can be activated sequentially. Then, in a second timeslot following the first, the second transmitting antenna can be activated; again, during the second timeslot, both the first receiving antenna and the second receiving antenna can be activated sequentially. Furthermore, techniques have been described above in which a housing is attached to a patch via a connecting element. The housing surrounds a circuit carrier structure on which one or more RF components are mounted. Besides a cable connection between the one or more RF components and a further circuit carrier structure located away from the surface, where, for example, RF signal generation or analog-to-digital conversion takes place, it would also be conceivable that in such techniques, the generation of RF signals and / or the analog-to-digital conversion takes place close to the surface by components on the circuit carrier structure surrounded by the housing. The preceding section described techniques in which a housing surrounding a circuit carrier structure is mechanically fixed to a flexible support structure using a magnetic connection. However, other mechanical fixing methods can also be used, such as a clip connection, a snap fastener, or a textile hook-and-loop fastener. QUOTES INCLUDED IN THE DESCRIPTION This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature DE 10 2020 110 901 A1

[0005] DE 10 2022 115 031 A1

[0005] US 2023 0 154 450 A1

[0056]

Claims

Device for measuring vocal tract movements of a person, the device comprising: - at least one flexible support structure (80, 85, 180, 580) configured to be adhered to a skin surface in the vocal tract region of the person, - a first ultra-wideband antenna (81) arranged on the at least one flexible support structure and configured to transmit first radio waves towards the skin surface of the person, - a second ultra-wideband antenna (86) arranged on the at least one flexible support structure (80, 85, 180, 580) configured to detect second radio waves emanating from the skin surface, and - an electronic circuit (71) configured to perform a radar measurement of the vocal tract movements based on transmitted signals for the first ultra-wideband antenna and received signals from the second ultra-wideband antenna. Device according to claim 1, wherein the at least one flexible support structure comprises a first flexible support structure (80) and a second flexible support structure (85) separate from the first flexible support structure, wherein the first ultra-wideband antenna (81) is applied to the first flexible support structure (80), wherein the second ultra-wideband antenna (86) is applied to the second flexible support structure (85). Device according to claim 2, further comprising: - one or more alignment markers (84, 89) on the first flexible support structure (80) and the second flexible support structure (85), wherein the alignment markers indicate an orientation for adhering the first flexible support structure with the first ultra-wideband antenna and the second flexible support structure with the second ultra-wideband antenna to the skin surface. Device according to claim 3, wherein, when aligning the first flexible support structure (80) and the second flexible support structure (85) using the alignment markers (84, 89), the first ultra-wideband antenna (81) and the second ultra-wideband antenna (86) are arranged relative to each other such that the field of the first radio waves emitted by the first ultra-wideband antenna is largely orthogonal to the field of the second radio waves detected by the second ultra-wideband antenna (86). Device according to one of claims 2 to 4, further comprising: - a third ultra-wideband antenna (82) arranged on the first flexible support structure (80) and configured to emit third radio waves towards the skin surface of the person, wherein the first ultra-wideband antenna (81) and the third ultra-wideband antenna (82) are arranged on the first flexible support structure (80) such that the field of the first radio waves emitted by the first ultra-wideband antenna is largely orthogonal to the field of the third radio waves emitted by the third ultra-wideband antenna (82). The device according to claim 5, further comprising: - a high-frequency switch (72) arranged on a first circuit support structure (81), wherein the high-frequency switch (72) is configured to provide a transmit signal applied to an input side of the high-frequency switch depending on a control signal of either the first ultra-wideband antenna (81) or the third ultra-wideband antenna (82), and - a signal splitter arranged on the first circuit support structure (83) and configured to split an input signal provided by a cable (77) into a supply signal for operating the high-frequency switch, the control signal of the high-frequency switch and the transmit signal. Device according to claim 6, further comprising: - a first connecting element (75) which is configured to electrically contact and mechanically fix the ultra-wideband antennas arranged on the first flexible support structure (80) to the high-frequency switch (72) arranged on the first circuit support structure (83). Device according to one of claims 2 to 7, further comprising: - an amplifier (79) arranged on a second circuit support structure (87), and - a second connecting element (76) configured to electrically contact and mechanically fix the second ultra-wideband antenna arranged on the second flexible support structure to the amplifier arranged on the second circuit support structure (87), wherein the device is configured to couple the received signal of the second ultra-wideband antenna into the amplifier (79) via the second connecting element (76). Device according to claim 6 or 7 and according to claim 8, further comprising: - a further circuit carrier structure (60) which is connected to the first circuit carrier structure (83) and the second circuit carrier structure (87) via high-frequency cables (77, 78) and on which one or more high-frequency components (79) of the electronic circuit (71) are arranged. Device according to claim 1, wherein the first ultra-wideband antenna (81) and the second ultra-wideband antenna (86) are arranged on the same flexible support structure (180, 580). Device according to claim 10, wherein the first ultra-wideband antenna (81) and the second ultra-wideband antenna (86) are arranged on the same flexible support structure (180, 580) such that the first radio waves emitted by the first ultra-wideband antenna exhibit an attenuation due to field orthogonality of at least 6dB when received by the second ultra-wideband antenna (86). Device according to claim 10 or 11, further comprising: - a third circuit support structure (183) on which one or more components of the electronic circuit (71) are arranged, wherein the third circuit support structure (183) is enclosed in a housing (515), - a further circuit support structure (60) which is connected to the third circuit support structure (83) via a high-frequency cable (77, 78) or a wireless communication link and on which one or more further components of the electronic circuit (71) are arranged, and - a third connecting element (176, 576) which is configured to establish an electrical contact between the one or more components arranged on the third circuit support structure and the first ultra-wideband antenna (81) and the second ultra-wideband antenna (86). Device according to claim 12, further comprising: - a battery contact arranged on the third circuit carrier structure and configured to accommodate a battery and provide a supply voltage for a high-frequency signal generator of the electronic circuit arranged on the third circuit carrier structure. Device according to claim 12 or 13, wherein the third connecting element (176, 576) comprises at least one magnet (577, 577.1) for mechanical fixing and at least one spring contact pin and / or at least one contact surface (578) for electrical contacting. Device according to one of the preceding claims, wherein the first ultra-wideband antenna (81) and the second ultra-wideband antenna (86) each have a bow-tie geometry with two antenna wings. Device according to claim 15, wherein a feed point of the first ultra-wideband antenna is located between the two antenna wings of the second ultra-wideband antenna in the bow-tie geometry. Device according to one of the preceding claims, further comprising a communication interface (175) configured to send digital measurement data of the radar measurement generated by the electronic circuit (71) to another communication interface. Device according to claim 17, wherein the communication interface is a wireless communication interface (175.1) configured to wirelessly transmit digital measurement data of the radar measurement generated by the electronic circuit (71) to another wireless communication interface (175.2). System comprising: - the device according to one of the preceding claims, - a processor (61) and a memory (62), wherein the processor is configured to load and execute program code from the memory and to generate a voice signal associated with the movements of the vocal tract based on digital measurement data from the radar measurement. System according to claim 19, further comprising: - a communication interface (175), wherein the processor is configured to receive the digital measurement data of the radar measurement via the communication interface. Patch (500) for measuring vocal tract movements of a person, the patch comprising: - a flexible carrier structure (580) configured to be adhered to a skin surface in the vocal tract area of ​​the person, - at least one ultra-wideband antenna (81, 86) arranged on the flexible carrier structure, and - a connecting element (576) configured to provide electrical contact of the at least one ultra-wideband antenna and to provide a releasable mechanical fixation of a housed circuit carrier structure to the flexible carrier structure. Plaster according to claim 21, wherein the releasable mechanical fixation comprises a magnetic connection (577, 577.1). Patch according to claim 21 or 22, wherein the electrical contacting comprises at least one spring contact pin (578.1) and / or at least one contact surface (578) for a spring contact pin. Patch according to one of claims 21 to 23, wherein the patch comprises: - a bearing surface (577) projecting towards a surface in which the at least one ultra-wideband antenna extends, which surrounds contact elements (578, 578.1) of the electrical contacting in a collar-like manner.

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