BACKGROUND

[0001] The use of hearing devices are well known. Many hearing devices involve an antenna configured to receive and/or transmit radio frequencies (RF) which are then modulated and/or demodulated to produce (possibly with other information) a sound signal that can be provided to a user through a speaker. Hearing devices often come in the form of in-ear plugs or over-the-ear headsets . Sound quality and consistency have been issues facing construction of new hearing devices.

SUMMARY

[0002] A hearing protection device is presented that includes a first earmuff and a second earmuff. The hearing protection device also includes a connector that connects the first earmuff to the second earmuff. The connector includes a first mechanical spring that connects to the first earmuff on a first spring first end and connects to the second earmuff on a first spring second end. The first mechanical spring has a length extending from the first spring first end to the first spring second end. The connector also includes a second mechanical spring that connects to the first earmuff on a second spring first end and connects to the second earmuff on a second spring second end. The first and second mechanical springs provide a biasing force urging the first and second earmuffs toward a wearer’s head. The hearing protection device also includes an antenna element with an antenna length of conductive material and a feed point connecting the antenna to a receiver. The antenna element is wholly enclosed within a housing of the connector. The antenna is configured to receive a radio signal in the 87.5-280 MHz range.

[0003] Embodiments described herein offer many advantages over prior art antenna configurations for hearing protection devices. For example, embodiments herein take advantage of at least some mechanical parts present in a hearing protection device. Embodiments herein also protect the antenna from mechanical stress while maintaining enough exposure for good function. Embodiments herein provide antennas with low ohmic losses and high performance and have negative imaginary part and no resonances in the frequency bands required for DAB/FM receiver chip system. The antenna could also be of resonant type depending on the utilized receiver. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document.

[0005] FIG. 1 illustrates an environment in which embodiments of the present invention may be useful.

[0006] FIG. 2 illustrates an example hearing protection device in accordance with an embodiment of the present invention.

[0007] FIG. 3 illustrates a schematic of an example hearing protection device in accordance with an embodiment of the present invention.

[0008] FIGS. 4A-F illustrate an example of a direct radiator antenna in an embodiment of the present invention.

[0009] FIGS. 5A-E illustrate an example of an indirect radiator antenna in an embodiment of the present invention.

[0010] FIGS. 6A-6E illustrate another example of an indirect radiator antenna in an embodiment of the present invention.

[0011] FIG. 7 illustrates a further example of an indirect radiator antenna in an embodiment of the present invention.

[0012] FIGS 8A-8E illustrate another embodiment of an internal antenna within a headband connector in an embodiment of the present invention.

[0013] FIGS. 9A-9E illustrate antennas for a hearing protection device in an embodiment of the present invention.

[0014] FIG. 10 illustrates a method of providing hearing protection with a hearing protection device in accordance with embodiments herein.

DETAILED DESCRIPTION

[0015] Reference will now be made in detail to certain embodiments of the disclosed subject matter, examples of which are illustrated in part in the accompanying drawings. While the disclosed subject matter will be described in conjunction with the enumerated claims, it will be understood that the exemplified subject matter is not intended to limit the claims to the disclosed subject matter.

[0016] In the methods described herein, the acts can be carried out in any order without departing from the principles of the disclosure, except when a temporal or operational sequence is explicitly recited. Furthermore, specified acts can be carried out concurrently unless explicit claim language recites that they be carried out separately. For example, a claimed act of doing X and a claimed act of doing Y can be conducted simultaneously within a single operation, and the resulting process will fall within the literal scope of the claimed process.

[0017] The term “about” as used herein can allow for a degree of variability in a value or range, for example, within 10%, within 5%, or within 1% of a stated value or of a stated limit of a range, and includes the exact stated value or range.

[0018] The term “substantially” as used herein refers to a majority of, or mostly, as in at least about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, or at least about 99.999% or more, or 100%.

[0019] Many different audio frequencies exist for transmitting sound from a source to a receiver. While AM and FM frequencies are both well known, Digital Audio Broadcasting (DAB) is a digital radio standard that is becoming more common. When compared to analog FM, for example, DAB is more efficient with respect to its spectrum use, allowing for more radio services for a given bandwidth. DAB can also be more robust with regard to noise and multipath fading. However, while FM operates around the 100 MHz range, DAB operates around 174-280 MHz. DAB receiving chips typically have an antenna and matching system different from those used in conventional RF interfaces. Some DAB chips have a high impedance input with a tunable varactor. Therefore, a matching circuit should resonant the capacitive behavior of the antenna with a fixed inductor. Resonance can then be tuned by tuning the internal varactor. The capacitive behavior of the antenna is key for addressing tuning the modified behavior director within the matching circuit. Resonance occurs when the voltage is high, and tuning is required to get the maximum voltage output. Without this behavior, then resonance is not possible, and the voltage output will not maximize. Higher voltage, the better signal quality of received signals.

[0020] An antenna for a DAB receiving personal protective equipment (PPE) system, therefore, needs to have different behavior than traditional antennas which are often tuned to 50 Ohms and have a zero imaginary part of the impedance. In contrast, an antenna for a DAB receiving system must have a high negative imaginary part and a low real part of the impedance. Additionally, the antenna should be mechanically robust. [0021] FIG. 1 illustrates an environment in which embodiments of the present invention may be useful. An individual 10, wearing personal protective equipment 20, can receive signals in the DAB 40 and/or FM 50 wavelength ranges. While not drawn to scale, FIG. 1 does illustrate that FM signal wavelengths 52 are longer than DAB signal wavelengths 42, often many times longer than a mechanical length of an antenna 30.

[0022] Personal Protective Equipment (PPE) often includes a headset with a set of over- the-ear hearing protection devices, often referred to as ear muffs. However, while a headset is illustrated and described, it is explicitly contemplated that other configurations may be possible. For example, FIG. 1 illustrates a headset with a headband connecting two earmuffs, 22R and 22L. However, while an over-the-head connection is illustrated, two earmuffs could also be connected using a neckband, or other suitable connection mechanisms. Each ear muff 22L, R is configured to dampen ambient environmental sounds, but also includes electronic circuitry configured to pick up ambient sounds and reproduce them, through internal speakers, at a sound level safe for a user. However, it is important that received containing at least sound information received and transmitted through electronic means be reproduced as close to nature as possible. In order to do this, an antenna for a hearing protection device needs to have an omnidirectional radiation pattern with little gain deviation. This allows the hearing protection device to be part of a Natural Interaction Behavior (NIB) communication system. Omnidirectional behavior is also important for a DAB antenna which is omni-receiving, and needs to be well-received in any direction the user’s head is pointing.

[0023] A NIB communication system uses the receiving signal strength to determine the distance between users wearing different headsets. Using the determined distance, a volume level may be derived, so that users moving apart will perceive the sound level being attenuated with increasing distance.

[0024] In one preferred embodiment, the antenna is integrated into one of the headset’s cups only. This can reduce the cost of manufacturing the headset, but increases the difficulty of providing natural-sounding reproduced sound as the antenna needs to receive signals in a 360° range around a user’s head. This requires the antenna to work properly with a human head blocking a portion of the range. While a single antenna is contemplated in many embodiments described herein, in other embodiments it is contemplated that a second antenna is present in a second earmuff. [0025] FIG. 2 illustrates an example hearing protection device in accordance with an embodiment of the present invention. Headset 100 includes two over-the-ear hearing protection devices 102 and 104 connected by a headband 114. Hearing protector devices 102, 104 are mechanically connected by headband 114, which may also include padding 112 for user comfort. The mechanical connection may include one or more metallic spring wires 103 to keep hearing protection devices 102 in place by applying a certain pressure to the human head. The spring wires can be supported by a sheet of metal or plastic encased in a soft material which also acts like a cushion to enhance comfort for the user while wearing headset 100.

[0026] Each hearing protector device 102 may include a microphone (not shown), which in a preferred embodiment may be configured such that wind noise is reduced. Additionally, each hearing protector device 102 may in a preferred embodiment also include cushioning 116 which may be configured to both increase user comfort and dampen ambient sounds. [0027] FIG. 3 illustrates a schematic of an example hearing protection device in accordance with an embodiment of the present invention. Hearing protection device 300 may in a preferred embodiment be similar to hearing protection device 100 of FIG. 2. Device 300 may also include control circuitry such as storage and processing circuitry. Storage and processing circuitry may include storage such as nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid-state drive), volatile memory (e.g., static or dynamic random-access-memory), etc. Processing circuitry in storage and processing circuitry may be used to control the operation of device 300. This processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processor integrated circuits, application specific integrated circuits, or other such devices as known to those practiced in the art.

[0028] Storage and processing circuitry may be used to run software on device 300. The software may handle communications, may process sensor signals and take appropriate action based on the processed sensor signals (e.g., to turn on or off functions in device 300, to start or stop audio playback, etc.), and may handle other device operations. To support interactions with other PPE equipment, storage and processing circuitry may be used in implementing communications protocols. Communications protocols that may be implemented using storage and processing circuitry include wireless local area network protocols (e.g., IEEE 802.11 protocols — sometimes referred to as WiFi® and WiGig), protocols for other short-range wireless communications links such as the Bluetooth® protocol, cellular telephone protocols, as well as others known to those practiced in the art. For example, the protocol described in WO 2016/200950, published on December 15, 2016, which is incorporated herein by reference, may be used in some embodiments.

[0029] Device 300 includes a pair of earmuffs 310 connected by an earmuff connector 318. Earmuffs 310 include cushioning 312, a speaker 314, and other features 316. For example, PCB board may be located within earmuff 310.

[0030] Device 300 also has an antenna 340 configured to receive wireless radio signals, such as DAB or FM signals, using receivers 354, 352, respectively. In addition to antenna 340, device 300 also has a PCB board 370. PCB board 370 may include a ground plane 372 and / or a reference plane 374. PCB board may also include other components 376. Power to components of device 300 is provided by power source 320.

[0031] Device 300 may include microphones, speakers, tone generators, and other audio components (see, e.g., one or more speakers 314). Microphones 330 may gather voice signals and/or ambient noise signals. Speakers may play back sound for a user either at ambient levels or after being processed by control circuitry.

[0032] Device 300 may also include a power source 320, such as a battery, for example, to provide power to the circuitry of device 300. A battery 320 may be a rechargeable battery, chargeable either in a wired or wireless configuration. In another embodiment, battery 320 is not be a rechargeable battery.

[0033] Earmuff connector 318 may be a simple headband, including some cushioning 320 for comfort of a user. Earmuff connector 318 also includes one or more metal springs 322 that extend the length of earmuff connector 318 and connect to earmuffs 310 at earmuff connections 324. Springs 322 provide a biasing force that urges earmuffs 310 toward a user’s head, keeping hearing protection device 300 in place.

[0034] Personal protective device 300 may also include an antenna 340, located within ear muff connector 318. Antenna 340 may be a direct radiator 352, or an indirect radiator 354. In embodiments where antenna 340 is a direct radiator, springs 322 act as antenna 340, fed by a feed point 388. In embodiments where antenna 340 is an indirect radiator 358, separate conducting elements are present, each with a length 344, and a shape 380. The shape may include curvature 382. In some embodiments, the conducting elements extend at least partially parallel to springs 322. Coupling between feeding shapes and indirect radiator can occur either capacitively, inductively or with a combination of both.

[0035] Antenna 340 may also be a planar antenna, with a length 344 that is significantly longer than a length of earmuff connector 318. Planar antenna may have a repeating element 384 that repeats at least partially along a length of ear muff connector 318.

[0036] Antenna 340 is fed at a feed point 388. In some embodiments, a feed point is located at a topmost part of ear muff connector 318. However, feed point 388, in other embodiments, is positioned at ear muff connection 324. Feed point 388 can also be positioned elsewhere along ear muff connector 318. Antenna 340 may also include other features 357.

[0037] Antenna 340 has an impedance 390 that can be characterized as having a real portion 394 and an imaginary portion 392. Antenna 340 has a large, negative imaginary portion and a reduced real portion when compared to a standard resonant-receiving antenna. It is important that the imaginary portion be at least -50 to have good signal reception. In some embodiments, the imaginary portion is in a range of -50 to -1400.

[0038] Hearing protection device 300 also includes a printed circuit board (PCB) 370 which has aground plane 372 and a reference plane 374 which are separate from the internal portion 342 of antenna 340. However, in some embodiments, internal portion 342 is connected to PCB 370. In some embodiments, PCB 370 also includes a conducting trace 376. PCB 370 may also have other features or functionality 378. In one embodiment, PCB is a rigid material configured to be fixed in place within an earmuff housing. The rigid PCB material may be fire-retardant, such as an FR-4 grade glass fiber and resin laminate.

[0039] In some embodiments, an antenna may have a feed that includes a positive antenna feed terminal and a ground antenna feed terminal. The transmission line may be used to couple radio-frequency transceiver circuitry to the antenna. The transmission line may have a positive signal path such as a line and a ground signal path. The transmission lines may include coaxial cable paths, microstrip transmission lines, stripline transmission lines, edge-coupled microstrip transmission lines, edge-coupled stripline transmission lines, twisted-pair transmission lines, transmission lines formed from combinations of transmission lines of these types, etc. Filter circuitry, switching circuitry, impedance matching circuitry, and other circuitry may be interposed within the transmission lines, if desired. The connections to the antenna or to a plurality of antennas may use an unbalanced transmission line for each antenna the transmission line may include filter circuitry, switching circuitry, impedance matching networks and other items known to those practiced in the art.

[0040] Device 300 includes an FM receiver 352 configured to receive wireless signals in the FM bandwidth. Additionally, device 300 includes a DAB receiver 354, configured to receive wireless signals in the DAB bandwidth. Receiver 352, 354 may be located externally or internally within antenna 340. Antenna 340 may also include other features 358.

[0041] In some embodiments, while a portion of an antenna, e.g. antenna 340, is located within earmuff connector 318, an external antenna portion 350 is also present.

[0042] An external antenna portion 350, can be described as having a length 362, a diameter and a tum-by-tum distance 364. It may also have other features 366. Because the wavelength of a DAB signal is longer than a mechanical end-to-end length of antenna 340 (e.g. a length 122 of antenna 120 illustrated in FIG. 2), it is desired to increase an overall electrical material length 362 of antenna 340. As described in greater detail in FIG. 9C, the tum-by-tum radius 364 and the diameter may be consistent for antenna portion 350, or it may vary along the length of external portion 350. Other mechanical properties my also vary along the length of the antenna.

[0043] FIGS. 4A-4E illustrate an antenna in accordance with an embodiment of the present invention. A hearing protection device, such as device 100, includes a connector that extends between two earmuff units. The connector typically consists of a mechanical connection within a headband. The headband typically includes one or more metallic springs that keep the earmuff units in place over a user’s head by applying a biasing force that urges the earmuff toward the user’s head. As discussed below, in some embodiments, metallic springs can be realized as spring wires. The external components of the hearing protection device, such as the headband housing, as well as the earmuffs themselves, have been removed for ease of understanding.

[0044] Antenna 400 utilizes metallic springs 402 and 404 as direct radiators for a DAB/FM public broadcast receiving antenna. Feeding wires 422, illustrated in FIG. 4F, extend from a printed circuit board (outlined as PCB 410), are connected directly to headband springs 402, 404. [0045] Both springs 402, 404 are fed differentially, which generates a maximum voltage difference, resulting in an electric field 460 that can radiate. Because of reciprocity, the receiving path behaves similar. When receiving, both springs 402, 404 can be considered as two arms of a dipole which capture the electromagnetic fields 460. The feeding point 412 then supplies a differential signal, in one embodiment, signal to the receiving network on the PCB. In another embodiment, the feeding point provides a quasi-differential signal.

[0046] FIGS. 4B and 4C illustrate simulated results of electric fields produced when springs 402, 404 are fed with a differential signal. The directional pattern of this example is shown in FIG. 4C. FIGS. 4D and 4E illustrate the absolute value of the imaginary and real portions, respectively, of the impedance resulting from the simulation.

[0047] FIG. 4A illustrates an embodiment where feeding point 412 is at substantially the topmost location of springs 402, 404, and substantially centered with regard to a human head. However, other positions are expressly contemplated. For example, a feed point could be located at either end of either spring 402 or 404. Alternatively, feed point 412 could be located in an asymmetric position, closer to, or further from, the PCB board than from an opposite earmuff. Depending on the specification of a given headset, another feeding point 412 may be more suitable. However, placing antenna 400 on a topmost position may cause it to be more exposed to EM fields and the pattern may be more omnidirectional.

[0048] Antenna 400 utilizes the existing spring headband wires of a hearing protection headset as active receiving elements for a DAB/FM public broadcast receiving system, reducing the need for an external antenna or additional components. Additionally, the antenna is protected against mechanical stress, but is still sufficiently exposed. For compact devices, such as hearing protectors, often worn in conjunction with helmets, using existing components for dual purposes reduces the footprint of the device. The spring wires are galvanically coupled to a feeding point 412, which can be positioned according to the needs of a given headset design. Additionally, the design of antenna 400 allows for flexibility in directional pattern and impedance by selecting a different feeding point.

[0049] Additionally, as illustrated in FIGS. 4D and 4E, there is a low real part of the impedance and a negative imaginary part. There are low ohmic losses, resulting in high performance. Additionally, there is no resonance in the frequency bands of interest, making it useful for a DAB/FM receiving chip system. [0050] FIGS. 5A-5E illustrate another antenna configuration in an embodiment of the present invention.

[0051] While antenna 400 uses metallic springs 402, 404 as direct radiators, antenna 500 utilizes a spring system 510 as indirect or parasitic radiators. Unlike the system illustrated in FIGS. 4A-4E, there is no galvanic connection between the feeding network 520 and the headband springs 510. The received (or transmitting) energy is transferred from (or to) the headband springs by magnetic- and electrical-field coupling mechanisms that extend between, and beyond, network 520 and springs 510. The currents inside feeding structure and headband springs are illustrated by the arrows in FIG 5B generating a magnetic field illustrated by the arrows in FIG. 5C.

[0052] Feed network 520 is connected to a feed port 530. As illustrated in FIG. 5A, the feeding point 530 of antenna 500 is located at a point on the top of the structure. Other configurations are illustrated in FIGS. 6-7. In addition to the three variants shown, other versions of the feeding and coupling network to feed energy from or to the metallic headband springs are expressly contemplated. The power transfer from feeding network 520 to the headband springs 510 is done by using electric- and/or magnetic -coupling. The potential on the long arms 522 of the coupling network generates mainly an electric field. This field influences the parallel running headband springs 512 and mainly capacitively couples the electric energy into the spring SYSTEM 510. For example, at one point in time, the negative charge on the coupling arm attracts a positive charge on the spring wire. The received energy is alternating over time so the charges get moved with the frequency of operation. These moving charges create an alternating current inside the spring (or, alternatively, from the spring wire to the coupling network).

[0053] The alternating potential difference on the arms 522 of the coupling network also create alternating currents which again create a changing magnetic field. This field also extends around the headband spring wire and induces an electric voltage.

[0054] Simulations of the coupling mechanism are shown in FIGS. 5B-5C. FIG. 5B illustrates currents on the conductors and FIG. 5C illustrates magnetic fields surrounding the conductors. The simulation was performed with state of the art commercial software using time-domain solving mechanisms.

[0055] FIGS. 5D and 5E illustrate the impedance of the variant illustrated in FIG. 5A. [0056] An indirect radiator system, such as that illustrated in FIGS. 5-7, utilizes existing spring headband wires of a hearing protection headset as passive or parasitic receiving elements for a DAB/FM public broadcast receiving system. The feeding can be galvanically isolated. Additionally, as described with respect to the embodiment of FIGS. 4A-4E, the feeding and coupling network can be adapted to the needs of a given product, as illustrated in the differences between current, magnetic fields and impedance between antenna systems 500 and 600.

[0057] FIGS. 6A-6E illustrate a second indirect radiation antenna configuration in an embodiment of the present invention. The feeding position 630 of conducting system 620 is asymmetrically located above an earmuff. Antenna 600 operates in a differential-mode and generates opposite alternating currents and opposite potentials on the two headband springs 612, 614 of spring system 610, in a dipole-like manner.

[0058] Simulations of the coupling mechanism are shown in FIGS. 6B-6C. FIG. 6B illustrates currents on the conductors and FIG. 6C illustrates magnetic fields surrounding the conductors.

[0059] FIGS. 6D and 6E illustrate the impedance of the variant illustrated in FIG. 5A. [0060] FIG. 7 illustrates a third indirect antenna configuration 700 in an embodiment of the present invention. The feeding can also be being adapted to support common mode feeding, as illustrated in FIG. 7. As illustrated in FIG. 7, only two arms 722 are present, in contrast to the 4-arm configuration of antennas 500. Feeding system 720 extends from a first arm 722, at a feed point 730, to a second arm 724. Arms 722 and 724, as illustrated in FIG. 7, are on opposing springs.

[0061] Similar to the system of FIGS. 4A-4E, the various embodiments of FIGS. 5-7 allow for re-use of mechanical parts that are already present in a hearing protection device. Additionally, the hearing protection device can be constructed such that the entire antenna is enclosed within the headband, so no external antenna, such as a whip antenna, is required. This protects the antenna from mechanical stress while still keeping the antenna sufficiently exposed. Additionally, there is flexibility available in choosing a different feeding point, allowing for different directional patterns and impedance.

[0062] Additionally, there is a low real part of the impedance and a negative imaginary part. There are low ohmic losses, resulting in high performance. Additionally, there is no resonance in the frequency bands of interest, making it useful for a DAB/FM receiving chip system.

[0063] In contrast to antenna 400, embodiments 500, 600 and 700 provide additional benefits. Galvanically isolated the feeding system protects the receiver against electrostatic discharge (ESD). Additionally, said systems do not require attachment of wires to the moving headband springs, which presents mechanical difficulties. Additionally, the active electronics can be better encapsulated for mechanical robustness.

[0064] FIGS 8A-8E illustrate a planar antenna within a headband connector in an embodiment of the present invention. FIG. 8A illustrates a hearing protection device 800 with a connector 810 between two earmuffs. The housing of connector 810 is removed in FIG. 8B to illustrate planar antenna 820 more clearly. As used herein, the term “planar” refers to the geometry of antenna 820 prior to installation within headband 810. Due to the geometry of headband 810, antenna 820 takes on curvature so that its placement is substantially imperceptible to a user of the hearing protection device 800.

[0065] Planar antenna 820 can be placed on or inside a headband 810, for example within a cushioning layer, within a structural layer, etc. In some embodiments, planar antenna is placed on the most exposed top position to improve omnidirectional reception of radio energy. In one embodiment, antenna 820 is a meander type dipole antenna with the feeding point 826 in the middle of the structure, as illustrated in FIG. 8B. However, other planar antenna types are also expressly contemplated, such as, for example, any of dipole, loop, folded dipole, fractal, log -periodic, Y agi. It is also expressly contemplated that antenna 820 may use multiple planar layers like patch antennas. Additionally, in some embodiments, antenna 820 is an integral part of the headband, e.g. it could be printed on or adhered to the inside of the housing of 810 with conducting ink. Additionally, antenna 820 could be a 3D- printed part consisting of plastic material and conducting material.

[0066] A structure of antenna 820 can for example consist of a flex-printed-circuit- board with one or multiple structured conducting layers. The structured conducting layers may include copper, silver, aluminum or another conducting material. Non-conducting materials may also be present in some layers, such as thin polyimide, PET, PTFE or another suitable material. FIG. 8B illustrates only one conductive layer and one non-conductive layer. However, it is expressly contemplated that additional layers could also be present. For example, the antenna could be similar to the construction illustrated in PCT Application IB2020/055912, filed on June 23, 2020. In one embodiment, antenna 820 includes a copper layer on a polyimide substrate, similar to those used in standard flex-PCB applications. In one embodiment, the substrate is an electrically low-loss type. As illustrated in FIG. 8B, the antenna 820 can then be placed inside the plastic headband supporting portion, such that it is substantially imperceptible to a user.

[0067] In one embodiment, meandered dipole antenna element 820 can also be made of a structured conducting sheet made of, for example, copper or aluminum. Antenna element 820 and can be integrated directly inside the plastic headband supporting part, in one embodiment, such that the substrate is the headband supporting plastic part itself.

[0068] Feeding of antenna 820 can be done, in one embodiment, by a thin coaxial cable which connects the main PCB with the antenna element 820 at feeding point 826.

[0069] Because of the dipole style type of this exemplary antenna, the directional pattern will look as illustrated in FIG. 8C.

[0070] In an embodiment where the antenna is placed on the most top location of the hearing protection device, where it is most exposed, the performance of the antenna is good, as illustrated in FIG. 8C. The directional pattern covers nearly the whole upper hemisphere and also covers the front and the back very well. While there are two nulls in the lower hemisphere in direction of the cups, this is due to the dipole style shape of the antenna and can be further optimized by modifying the geometry of the antenna 820, particularly at the ends.

[0071] Special care should be taken when designing the antenna to keep enough distance to the metallic conducting headband springs of the headset. Because the antenna element is right between both headband springs, a certain distance must be kept to the antenna element to minimize influence of the metallic parts on the antenna. If the distance is too low, the metal springs of the headband may ‘short circuit’ the meanders of the antenna structure by building a capacitively coupled bridge for high frequencies. The right distance can depend on the specific design. However, in some embodiments here, the distance is between about 5-10 mm.

[0072] FIGS 8D and 8E illustrate the antenna impedance. Antenna 820 is pure capacitively (Zim<0) with low ohmic losses (Zre). This means that this antenna is perfectly usable for the FM/DAB receiving chip. [0073] As illustrated in FIG. 8B, antenna 820 has a device length that is based on a winding length 822 and a number of winding structures 824. Each winding 822 is necessarily shorter than a width of connector 810. In one embodiment, as illustrated in FIG. 8B, windings 824 include sharp comers, however curvature may be present in some embodiments. The repeating portion 824 may be sinusoidal, or otherwise shaped. In some embodiments, repeating portion 824 is only repeated partway across a length of connector 810. For example, as illustrated in FIG. 8B, at an inflection point 826, repeating portions 824’ are mirrored versions of repeating portions 824.

[0074] Additionally, while a repeating portion 824 is illustrated with meander structures with a longer portion 822 perpendicular to a length of headband connector 810, it is also expressly contemplating that meander structures could have the longer portions 822 parallel to the length of headband connector 810. As illustrated in FIG. 8B, the number of meanders 824, in some embodiments, is at least 8, or at least 10, or at least 12, or at least 14, or at least 16, or at least 18, or at least 20.

[0075] Antenna 820 utilizes the existing headband supporting provision as a shell or support for a planar antenna element for a DAB/FM public broadcast receiving system. The feeding is galvanically coupled. The antenna element may occupy nearly the whole space between both headband springs (not called out in FIG. 8B) and can be completely sealed against environmental influences like dust or water. In addition, having the very exposed position on the very top of the hearing-protector is beneficial for good reception.

[0076] Antenna 820 is beneficial over prior art antennas in that it allows for re-use of mechanical parts already present in hearing protection devices, without the need for an external visible antenna portion. Antenna 820 is sufficiently protected against mechanical stress but still exposed to EM-fields. Additionally, antenna 820 is protected against environmental influences like dust or water as antenna may be sealed inside the headband supporting plastic. Additionally, while only one planar antenna structure is illustrated in FIG. 8B, there are many different planar antenna styles suitable for other embodiments, depending on the available space and layout of a headband housing 810. Antenna 820 also provides manufacturing benefits as a standard flex-PCB may be used.

[0077] FIGS. 9A-9D illustrate an antenna for a hearing protection device in an embodiment of the present invention. Described herein and illustrated in are several embodiments of antenna that are enclosed within, or placed on a connector between two earmuffs of a hearing protection device. In FIGS. 9A-9D, a hybrid antenna 900 is presented that incorporates both an internal component 910 and an external component 920. The external portion 920 (often referred to as a helical whip), in combination with the headband spring 910, form a dipole antenna structure 900. However, while the rear headband spring 910 is illustrated, it is expressly contemplated that other internal structures may be used, in other embodiments, such as a front headband spring (not shown), and / or a planar antenna construction such as that of FIGS. 8A-8E.

[0078] When using a monopole antenna, there is always the need for a “counter pole” for the helix to work properly. As described in greater detail in U.S. Provisional Patent Application Ser. No. 63/008120, filed on April 10, 2020, this can be accomplished by using a ground plane on the PCB, a ground trace on the PCB, or using a metallic sheet on the bottom of the monopole. Depending on the structure of the selected counter pole, it is always the goal to generate a dipole-like structure by either using a conducting plane to generate a mirror of the monopole or a second arm with opposite polarity with a trace or wire-like structure. As illustrated in FIG. 9A, one of the existing conducting headband springs 910 serves as a second arm of the dipole.

[0079] The differential feeding point 912 is illustrated as between the bottom of the helix 920 and the neighboring end of the headband spring 910. However, other placements are also possible.

[0080] FIG. 9B illustrates electric fields and how they span between both helix 920 and spring 910. FIGS. 9C-9D illustrate the antenna impedance, showing a resonance (Zim=0) at 250MHz, outside of the required frequency band forFM/DAB reception. The resonance can also be further shifted towards higher frequencies by altering the length and the turn-ratio of the helix. The imaginary part Z(im) falls below zero in the frequency bands of interest which are between 87,5MHz and 108MHz for FM and 174,16MHz and 239,968MHz for DAB. The real part shows higher values at higher frequencies, which can be adjusted by altering the design of helix 920.

[0081] Many options for altering the design of helix 920 are available, as described in the context of FIG. 9E.

[0082] Helix 950 includes conducting spring wire, in one embodiment, wound tightly. A material length of the conducting spring wire, in one embodiment, is longer than length 960. In one embodiment, the material length is at least twice, or at least three times as long as length 960. Helix should be formed from a conductive element, but also be mechanically stable. In one embodiment, helix 950 is made of steel, such as a heat-treated steel.

[0083] FIG. 9E illustrates an external portion of an antenna with a variable tum-to-tum distance over the whole length 960 of helix 950, as illustrated in a first tum-to-tum distance 962 compared with a second tum-to-tum distance 964. One turn of wire 952 itself can be considered as a combination of an inductive part (wire 952) and a capacitive part (coupling between neighboring turns 962, 964). The inductive part can be influenced by the length (the circumference, measured as n multiplied by diameter 954) and the thickness of wire 952. The capacitive part is influenced by the distance of one turn to another, e.g. distances 962, 964 as well as the thickness and turn-length of the wire. The whole antenna acts as multiple LC circuits in serial configuration, generating the overall impedance of helix 950. [0084] It is expressly contemplated that a helix portion of an antenna can have a constant turn diameter, as illustrated in FIG. 9A. Additionally, while FIG. 9E illustrates a shrinking tum-by-tum distance extending from a feed point 912 upwards, it is also expressly contemplated that the tum-by-tum distance could increase from the feed point 912, or could increase, then decrease; or could decrease, then increase. Other combinations are also expressly contemplated. While FIG. 9E illustrates a gradual increase in tum-by-tum distance, it is also expressly contemplated that tum-by-tum distance could increase in a stepwise fashion, e.g. a first tum-by-tum distance for ten turns and then a second tum-by- tum distance for another ten turns. In another embodiment, more than two tum-by-tum distances are present, for example three, four, five or more distinct turn distances are present along length 960. In another embodiment, the tum-by-tum distances are varied for different numbers of turns, for example a first tum-by-tum distance for four turns, a second tum-by- tum distance for an additional six turns, and a third tum-by-tum distance for another ten turns.

[0085] Varying a tum-to-tum distance can increases mechanical stability for the antenna, for example by having a smaller tum-by-tum distance positioned at the base of the antenna. It can also generate denser electrical fields where the tum-by-tum distance is smaller, for example near reference number 964, which can raise overall capacitance of the antenna impedance.

[0086] Using the approach of FIG. 9E, the impedance of the antenna can be very precisely modified without changing length 960 or diameter 954 of the helix. [0087] Additionally, while FIG. 9E illustrates an embodiment where diameter 954 remains substantially constant and tum-by-tum length changes, it is also expressly contemplated that diameter 954 could vary along length 960 instead of, or in addition to, tum-by-tum length. For example, helix 950 could have a bigger diameter (e.g. 8mm) on the bottom and a small diameter (e.g. 4.73mm) on the top. Alternatively, helix could have a small diameter on the bottom and a larger diameter on the top. In addition to tum-by-tum length and diameter, it is also envisioned that the thickness of conductor 954 could vary along length 960.

[0088] Changing the turn distance, the helix diameter and thickness of the conductor can also be combined to gain maximal flexibility for impedance and mechanical constrains. The change of the turn distance and/or the change in helix diameter and/or the change in thickness of the conductor can follow a certain mathematical function or can be freely defined. Possible mathematical functions can be a linear function or any other function like e.g. hyperbolic, rectangular or e-function or a combination of those.

[0089] Additionally, in one embodiment, to add top-loading to the previously described antenna solution, one possibility is to add a conducting cylindric solid or shell 970 to the top of helix 950. This can also be a conducting solid cylinder, which is placed inside or outside of the upper part of the existing helix, and which may short the upper windings.

[0090] With top-loading, the imaginary part is more negative as before, also preventing the resonance to occur. Top-loading also improves the ohmic losses in the antenna at higher frequencies as can be observed in the real part. Reduced ohmic losses and higher negative imaginary part of the impedance result in better performance of the antenna.

[0091] FIGS. 4-7 illustrate antenna constructions that utilize an existing headband spring as a counter pole for the whip helical antenna for a DAB/FM public broadcast receiving system. In the illustrated embodiment, the feeding is galvanically coupled and differential. Using the metallic headband spring saves space inside the cup and on the PCB for the electronic components. It eliminates the necessity for big GND structures to make the whip-antenna work.

[0092] The type of DAB receiving chip used in the new generation of public broadcast receiving hearing protectors uses an antenna and matching system which is quite different to usual RF interfaces. The chip offers a high impedance input with a tunable varactor. The matching circuit must be designed to resonant the capacitive behavior of the antenna with a fixed inductor. The chip is then able to tune the resonance to the desired frequency by tuning the internal varactor.

[0093] This brings with it, that the antenna must have different behavior than “usual” antennas which are tuned to 50 Ohms and, in the optimal case, already have zero imaginary part of impedance. In comparison to these antennas, the antenna in the DAB receiving system must to have high negative imaginary part of impedance and low real part of the impedance. There is also the requirement for increased mechanical robustness and some mechanical constraints given by the existing design of the housing of the hearing protector. [0094] The embodiment illustrated herein result in an enlarged negative imaginary part and the reduced real part of the antenna impedance. These designs also avoid a zero imaginary part, which would result in self resonance, in the frequency bands of interest. Self resonances are problematic for the intended matching circuit as it voids the chance of generating a variable LC-resonance in combination with the matching circuit and the varactor inside the receiver IC.

[0095] FIG. 10 illustrates a method of using a headset antenna in accordance with an embodiment of the present invention. Method 1000 may be useful for a headset antenna within a hearing protection device. A hearing protection device is designed to dampen ambient sound for a user. Microphones are configured to receive ambient sound, and the hearing protection device is configured to process the ambient sound to a safe level for a user. An antenna, such as the antennae described with respect to FIGS. 4-9, can be used for receiving Radio frequency (RF) signals, such as those in the FM or DAB wavelength spectrums and processing them to reproduce sound for a user.

[0096] In block 1010, ambient sound is received. Ambient sound may be received by a microphone, in one embodiment. A microphone may be located in one earpiece, as indicated in block 1002, or in both earpieces ofa headset, as indicated in block 1004. Sounds from the user are also captured by microphone 1005. Sound from another user of a similar hearing protection device may be demodulated by a transceiver after being picked up by an antenna.

[0097] In block 1020, reproduced sound is provided to a user. Sound may be reproduced in only one earmuff, as indicated in block 1012, or in both earmuffs, as indicated in block 1014. If a suitable antenna is present that is capable of allowing a headset to detect distance and direction of a sound, reproduced sound may also be provided such that it sounds omnidirectional, instead of from only two speakers. Other features may also be present, in other embodiments.

[0098] The reproduced sound may be provided such that it is not altered, as indicated in block 1022. In another embodiment, the sound is processed, as indicated in block 1024, for example to reduce the sound to a safe level for a user to hear. The reproduced sound may also have other features.

[0099] A hearing protection device is presented that includes a first earmuff and a second earmuff. The hearing protection device also includes a connector that connects the first earmuff to the second earmuff. The connector includes a first mechanical spring that connects to the first earmuff on a first spring first end and connects to the second earmuff on a first spring second end. The first mechanical spring has a length extending from the first spring first end to the first spring second end. The connector also includes a second mechanical spring that connects to the first earmuff on a second spring first end and connects to the second earmuff on a second spring second end. The first and second mechanical springs provide a biasing force urging the first and second earmuffs toward a wearer’s head. The hearing protection device also includes an antenna element with an antenna length of conductive material and a feed point connecting the antenna to a receiver. The antenna element is wholly enclosed within a housing of the connector. The antenna is configured to receive a radio signal in the 87.5-280 MHz range.

[00100] The hearing protection device may be implemented such that the antenna element includes the first and second mechanical springs.

[00101] The hearing protection device may be implemented such that the antenna element runs parallel to at least a portion of the first mechanical spring.

[00102] The hearing protection device may be implemented such that the antenna element includes a first conductive element, running parallel to the first mechanical spring, and a second conductive element, running parallel to the second mechanical spring.

[00103] The hearing protection device may be implemented such that the feed point is substantially at the highest point of the connector.

[00104] The hearing protection device may be implemented such that the feed point is asymmetrically located with respect to the antenna.

[00105] The hearing protection device may be implemented such that the feed point is located at a connection between the first mechanical spring and the first earmuff. [00106] The hearing protection device may be implemented such that the first and second earmuffs are configured to receive an ambient sound and provide a dampened sound through a speaker.

[00107] The hearing protection device may be implemented such that the antenna element is a planar antenna element.

[00108] The hearing protection device may be implemented such that the planar antenna element includes a plurality of windings.

[00109] The hearing protection device may be implemented such that the plurality of windings are perpendicular to the length.

[00110] The hearing protection device may be implemented such that the antenna element is a first antenna element. A second antenna element is external to the first antenna element.

[00111] The hearing protection device may be implemented such that the first antenna element is the first or second mechanical spring, and a second antenna element is a conducting element is wound helically within an external portion housing.

[00112] The hearing protection device may be implemented such that a length of the conducting element is longer than a length of the external portion housing.

[00113] The hearing protection device may be implemented such that the length of the conducting element is at least twice the length of the external portion housing.

[00114] The hearing protection device may be implemented such that the conducting element includes copper.

[00115] The hearing protection device may be implemented such that the conducting element includes a coating.

[00116] The hearing protection device of may be implemented such that the helical structure includes a plurality of turns. Each of the plurality of turns have substantially the same diameter.

[00117] The hearing protection device may be implemented such that the helical structure includes at least a first turn and a second turn. A first diameter of the first turn differs from a second diameter of the second turn.

[00118] The hearing protection device may be implemented such that the helical structure includes a plurality of turns, each turn having a diameter. The diameter of each turn increases from a first end of the helical structure to a second end of the helical structure. fool 19] The hearing protection device may be implemented such that the external portion includes a top-loading feature.

[00120] The hearing protection device may be implemented such that the top-loading feature includes a cylindrical feature.

[00121] The hearing protection device may be implemented such that the hearing protection device includes a microphone configured to receive the ambient sound, and a speaker within the earmuff to provide the dampened ambient sound.

[00122] The hearing protection device may be implemented such that the antenna element is an integral part of the connector.

[00123] The hearing protection device may be implemented such that the connector includes a cushion.

[00124] A headband for a hearing protection device is presented that includes a housing. The headband also includes an earmuff connection configured to couple the headband to an earmuff. The earmuff includes a printed circuit board. The headband also includes a mechanical spring within the housing configured to provide a biasing force to urge the earmuff toward a wearer’s head. The headband also includes a feed point configured to, when connected to the printed circuit board, provide a received current through an antenna element. The antenna element has an impedance with a real portion and an imaginary portion. The imaginary portion is negative. The magnitude of the imaginary portion is greater than a magnitude of the real portion.

[00125] The headband may be implemented such that the antenna element is wholly located within the housing.

[00126] The headband may be implemented such that the antenna element is integrated into the headband.

[00127] The headband may be implemented such that the mechanical spring is a first mechanical spring. The headband includes a second mechanical spring, and the antenna element is a direct radiator comprising the first or second mechanical springs coupled to the feed point.

[00128] The headband may be implemented such that the mechanical spring is a first mechanical spring. The headband includes a second mechanical spring. The antenna element is an indirect radiator. f l [00129] The headband may be implemented such that the antenna element includes a first length of conducting material that runs parallel to the first mechanical spring.

[00130] The headband may be implemented such that the antenna element includes a second length of conducting material that runs parallel to the second mechanical spring.

[00131] The headband may be implemented such that the antenna element is a planar antenna.

[00132] The headband may be implemented such that the planar antenna is integrated into the housing.

[00133] The headband may be implemented such that the planar antenna includes a length of conducting material at least twice as long as a length of the housing.

[00134] The headband may be implemented such that the feed point is located at a topmost point of the housing.

[00135] The headband may be implemented such that the feed point is located at the earmuff connection.

[00136] The headband may be implemented such that the antenna element is an internal antenna element configured to couple to an external antenna element to form a dipole antenna.

[00137] The headband may be implemented such that it includes a cushion element.

[00138] The headband may be implemented such that the antenna element is configured to receive radio wave signals around 87.5-280 MHz.