Patent Description:
Hearing devices, such as hearing aids, earphones, and earbuds, for example, are tiny, delicate devices comprising many electronic and metallic components contained in a housing small enough to fit at least partially in the ear canal of a human or behind the outer ear. Several electronic and metallic components in combination with a small size of the hearing device housing impose several design constraints on radio frequency antennas to be used in hearing aids possessing wireless communication capabilities. Further, the antenna in the hearing device has to be designed to achieve a satisfactory antenna gain despite the size limitation and other design constraints.

An antenna converts electric power into radio waves and vice versa. To be resonant, it is desirable for an antenna to have a physical length and/or electrical length related to the wavelength of a radio wave to be transmitted over the antenna (or a multiple of that length). However, in compact devices such as hearing aids, length of an antenna conductor is limited by the size and shape of the hearing aid device. Further, antenna gain requirements of the hearing aid device also need to be accounted when designing an antenna for the hearing aid to meet the specifications.

<CIT> relates to a hearing aid including a frame containing a transmitting and/or receiving unit, and an antenna containing two parts each configured as an open loop. First ends of the antenna loops, which are arranged at the same longitudinal end of the frame, are electrically shorted to each other via an electrical cross-connection or bridge, and second ends are in contact with the transmitting and/or receiving unit. The antenna loops can be additionally connected by a second bridge, wherein the first bridge is arranged at the front of the frame, and the second bridge is positioned at the rear of the frame. Each antenna loop has a length which corresponds with good approximation to a quarter or an eighth of the wavelength for which the transmitting and/or receiving unit <NUM> is designed.

<CIT> relates an antenna device for a radio communication device comprising two half loop radiating elements configured for multiple operation frequency bands and having a length of a half of an operating wavelength and being mirrored over a ground plane device, such as a component of a mobile phone, making the antenna function as a loop antenna. The two half loops each having a length of a half of the wavelength thus sum up to a total physical length equal to the wavelength.

<CIT> discloses an antenna assembly for a cellular phone configured to be operated with reduced near-field radiation by a first electrically-conductive loop in a first plane and a second electrically-conductive loop in a second plane orthogonal to the first plane, which loops are connected in series with a common feed point connection at a front end of the antenna. Each of the two loops can either be equal to one-half of the wavelength or to one-quarter of the wavelength. The antenna can be matched to a wireless communication equipment with a characteristic impedance by providing a balancing capacitor, a tuning capacitor, and a matching capacitor at the common feed point connection.

<CIT> discloses a wireless electronic device operating in a cell network and comprising physically connected first and second half-loop antennas coupled to a transceiver unit and switchable ground connection configured to switchably couple a ground plane and one of the first and second antennas to adjust a length of the one of the first and second antennas for antenna tuning.

The invention relates to a hearing device component as defined in claim <NUM>.

Preferred embodiments are defined in the set of dependent claims <NUM> - <NUM>.

The foregoing and other aspects of the present disclosure will become apparent to those skilled in the art to which the present disclosure relates upon reading the following description with reference to the accompanying drawings, in which:.

Example embodiments that incorporate one or more aspects of the apparatus and methodology are described and illustrated in the drawings. These illustrated examples are not intended to be a limitation on the present disclosure. For example, one or more aspects of the disclosed embodiments can be utilized in other embodiments and even other types of devices. Moreover, certain terminology is used herein for convenience only and is not to be taken as a limitation. "Approximately" and "substantially", as used herein, means within a range that does not alter performance to an undesirable degree and may facilitate manufacturing within constraints of the parts of the hearing device.

<FIG> is exploded view illustrating several parts of a hearing device component. The illustrated hearing device is a behind-the-ear (BTE) component <NUM> of a hearing aid. Other hearing device components may include, for example, an in-the-ear (ITE) component of a hearing aid, an earbud, or an earphone. The hearing device component can be part of an audio system that wirelessly receives audio or other signals from another device, component or system, such as a hearing aid controller, a mobile phone, a hearing loop system, an audio link device, or streaming device. Audio is transmitted to the user, for example, by a speaker in the hearing device component, a speaker connected to the hearing device component, or a cochlear implant connected to the hearing device component. The illustrated hearing aid component <NUM> can include a top housing <NUM>, a microphone cover <NUM>, an antenna substrate, such as a printed circuit board (PCB) assembly <NUM>, an antenna holder <NUM>, a hearing aid internal structure <NUM>, one or more adhesive tapes <NUM>, a bottom housing <NUM>, battery <NUM>, one or more microphones <NUM>, a signal processor <NUM>, and a sound tube <NUM> for outputting sound from a speaker (also known as a "receiver") <NUM> to a tubing <NUM>. The top housing <NUM> forms the top cover of the hearing aid. The top housing <NUM> may be made of a single material or composition of plural materials. In one example, the top housing <NUM> is made of plastic. In one example, the top housing forms a behind-the-ear hearing aid hook that covers the outside of a user's ear. The top housing <NUM> can connect the hearing aid component <NUM> to the tubing <NUM>, which can be connected to an ear mold.

The hearing aid component <NUM> can include the microphone cover <NUM> that forms a protective covering for the microphone <NUM> of the hearing aid component <NUM>. In one example, the microphone cover <NUM> provides noise isolation to the microphone of the hearing aid component <NUM> to reduce or prevent ambient noise at the input of the microphone of the hearing aid component <NUM>. The antenna PCB assembly <NUM> includes the two-half loop antenna <NUM> of the present invention as described further below with reference to <FIG>, <FIG>. In one implementation, the antenna PCB assembly <NUM> includes a flexible PCB structure. In one example, the antenna holder <NUM> is used as a frame structure for the PCB structure. In one example, the adhesive tape <NUM> is used to fix the antenna PCB assembly <NUM> to an internal structure of hearing aid component <NUM>.

The hearing aid component <NUM> can include the internal structure <NUM>. The internal structure <NUM> can hold one or more components and sub-components of the hearing aid component <NUM> necessary to support the functioning of the hearing aid component <NUM>. For example, the internal structure <NUM> can hold the microphone <NUM>, which may by a system including more than one microphone. The microphone may be directional i.e., pick up most sounds in front a person wearing the microphone, or omnidirectional i.e., pick up sounds from all directions. The internal structure <NUM> may further include a signal processor <NUM>, which receives electric signals received from the microphone and converts them into digital signals that can be processed further. The signal processor may comprise more than one processor. The signal processor <NUM> may be adapted to differentiate sounds, such as speech and background noise, and process the sounds differently for a seamless hearing experience. The signal processor in the internal structure <NUM> also supports cancellation of feedback or noise from wind, ambient disturbances, etc. The signal processor in the internal structure <NUM> also supports conversion of digital signals to analog signals, which are transmitted to the speaker <NUM> or a transducer of the cochlear implant. In some configurations, the speaker is in a component, such as a component to be worn in the ear, that is separate from the hearing aid component <NUM> and electrically connected to the hearing aid component. The internal structure <NUM> may also hold a wireless communication unit, such as a radio frequency (RF) transceiver <NUM>, that receives and optionally transmits wireless signals. The RF transceiver <NUM> may receive wireless audio signals and/or control signals from a remote device and convey them to the signal processor <NUM> or other part of the hearing aid component <NUM>. The RF transceiver <NUM> may also transmit wireless audio signals and/or control signals from the signal processor <NUM> or other part of the hearing aid component <NUM> to a remote device. The RF transceiver may be a transmitter only or a receiver only. The remote device may include a hearing aid controller, a mobile phone, a hearing loop system, an audio link device, a streaming device, or another hearing aid component, for example. Further, the internal structure <NUM> may hold other parts such as the battery <NUM>, etc. For simplification, components on the internal structure <NUM> that support the functionality of the hearing aid component <NUM> are not described in detail. The hearing aid component <NUM> also includes the bottom housing <NUM> that may form the outer cover and provide any needed support to the hearing aid component <NUM>. The top cover <NUM> and bottom housing <NUM> cooperate to form a housing enclosing the parts of the hearing aid component. Other housing configurations with one, two, or more housing parts can be used.

<FIG> is a schematic diagram illustrating the antenna substrate shown as the antenna printed circuit board (PCB) <NUM>. An antenna assembly can include the substrate and a conductor configured as an antenna. <FIG> illustrates the layout of the two-half loop antenna <NUM> as the conductor formed as a conductive trace on the antenna PCB <NUM>. For example, the conductor may be a <NUM> wide copper track formed on a <NUM> polyimide substrate. In another implementation, the two-half loop antenna may be implemented through MID (Molded Interconnect Devices) or LDS (Laser Direct Structuring) on parts of an internal frame or an external housing of the hearing aid or other known techniques of applying a conductor on a substrate or otherwise forming an antenna. The two-half loop antenna <NUM> includes a feeding point <NUM>, a first end section of the first half loop <NUM>, a second end section of the second half loop <NUM>, a mid-point <NUM>, and tuning elements <NUM>. <FIG> also shows a coupling point <NUM> and feeding lines <NUM> that can be used to connect the antenna <NUM> to the RF transceiver <NUM> via the feeding point <NUM>. The RF transceiver <NUM> can be installed at other locations. For example, the RF transceiver can be located at the feeding point <NUM> such that the feeding lines are very short or feeding lines are simply the output terminals of the RF transceiver and the end sections <NUM>, <NUM> of the first and second half loops are connected directly to the RF transceiver. The RF transceiver <NUM> can communicate a radio frequency signal (RF signal) to be received or transmitted over the two-half loop antenna <NUM>. The feeding lines <NUM> may be metallic wires, or channels of metallic conductors that carry the RF signal to or from the feeding point <NUM> of the two-half loop antenna <NUM> without loss or with minimal loss. The feeding lines <NUM> can include two parallel conductors that are laid out on the antenna PCB assembly <NUM> at a small separation distance. For example, the separation distance between the two parallel conducting channels of the feeding lines <NUM> is small enough that the currents (i.e., the current in the conductors corresponding to the signal carried by the feeding lines <NUM>) through the two parallel conductors effectively cancel any resulting magnetic flux due to current transmission through the two parallel conducting channels and there is little or no radiation of power from the feeding lines <NUM>. The feeding lines <NUM> can communicate the RF signal to be transmitted or received through the two-half loop antenna <NUM> via the feeding point <NUM>. In one implementation, a first conductor of the feeding lines <NUM> connects the RF transceiver to the first end section of the first half loop <NUM>, and a second conductor of the feeding lines <NUM> connects the RF transceiver to the second end section of the second half loop <NUM>. The connections of first end section of the first half loop <NUM> and the second end section of the second half loop <NUM> to the feeding lines <NUM> together comprise the feeding point <NUM>.

The feeding point <NUM> of the two-half loop antenna <NUM> marks the beginning of the two-half loop antenna <NUM> for the purpose of measuring a physical length of the two-half loop antenna <NUM>. The feeding point <NUM> is also the beginning point of the two-half loop antenna <NUM> where the two-half loop antenna <NUM> begins to transmit (that is, radiate) or receive the RF signal that is communicated from or to the RF transceiver <NUM>. At the feeding point <NUM>, the first end section of the first half loop <NUM> and the second end section of the second half loop <NUM> are in proximity to each other and conductors forming antenna segments of the first half loop and the second half loop of the two-half loop antenna <NUM> leading from the feeding lines may be parallel similar to the feeding lines. The feeding point <NUM> defines a point at which the conductors forming a first half loop <NUM> and a second half loop <NUM> become sufficiently separate from each other so that they can radiate or receive the RF signal. At opposite ends of the first and second half loops <NUM>, <NUM> from the end sections <NUM>, <NUM>, the first half loop and the second half loop of the two-half loop antenna <NUM> can have transverse segments <NUM> that join each other at a mid-point <NUM> of the two-half loop antenna.

<FIG> illustrates the geometry of the two-half loop antenna design with two rectangular loops. <FIG> includes the two-half loop antenna <NUM> with the feeding point <NUM>, the mid-point <NUM>, the first half loop <NUM>, the second half loop <NUM>, a first distal point <NUM> on the first half loop <NUM>, a first inversion point <NUM> on the first half loop <NUM>, a second distal point <NUM> on the second half loop <NUM>, a second inversion point <NUM> on the second half loop <NUM>, and tuning elements <NUM>. The configuration of the second half loop <NUM> is a mirror image of the configuration of the first half loop <NUM>. In the illustrated example, the first half loop <NUM> and the second half loop <NUM> can form individual half loops defining a substantially rectangular area each extending symmetrically and approximately parallel to each other along side faces of the hearing aid device <NUM> in a saddle-like manner. Although referred to as "half loops" the first half loop <NUM> and second half loop <NUM> can be asymmetrical with respect to each other in length and/or configuration. For simplification, and to focus on the geometry of the two-half loop antenna <NUM>, an RF transceiver, feeding lines, and a coupling point are not shown in <FIG>. The length of the first half loop <NUM> of the two-half loop antenna <NUM> is the length of the conductor of the two-half loop antenna <NUM> from the first end section of the first half loop <NUM> to the mid-point <NUM>, and the length of the second half loop <NUM> of the two-half loop antenna <NUM> is the length of the conductor of the two-half loop antenna <NUM> from the second end section of the second half loop <NUM> to the mid-point <NUM>. The sum of the lengths of the first half loop and the second half loop comprises the physical antenna length of the two-half loop antenna. The mid-point is approximately halfway along the physical length of the conductor of the two-half loop antenna <NUM>.

Referring to <FIG>, the hearing aid component includes a farthest point <NUM> illustrated, as an example, between the first half loop <NUM> and second half loop <NUM> of the two-half loop antenna <NUM>. An axial line <NUM> passes through the feeding point <NUM> and the mid-point <NUM>. A transverse plane <NUM> is perpendicular to the axial line <NUM> and intersects a point on the two-half loop antenna <NUM> that is farthest from the feeding point <NUM>. The intersection of the axial line <NUM> and the transverse plane <NUM> defines the farthest point <NUM>. As shown in <FIG>, there are two points <NUM>, <NUM> on the two-half loop antenna <NUM> that are equidistant and farthest from the feeding point <NUM>. In this example, the transverse plane intersects both of these points <NUM>, <NUM>. In one implementation, the configuration of the two-half loop antenna <NUM> is such that the distance between the feeding point <NUM> and the mid-point <NUM> is in the range of <NUM> to <NUM>/<NUM> of the distance between the feeding point <NUM> and the farthest point <NUM>.

The two-half loop antenna <NUM> can utilize lumped-impedance matching and/or loading to obtain a desired effective electrical length of the two-half loop antenna <NUM>. For example, an antenna having a physical length shorter than a quarter of the wavelength of the radio frequency signal to be transmitted over the antenna presents capacitive reactance, and some of the applied power is reflected back into the transmission line which travels back toward the transmitter. Therefore, to increase the effective electrical length of the antenna and to make the antenna resonant at the transmission frequency, a loading coil can be inserted in series with the antenna. The inductive reactance of the loading coil is approximately equal and opposite to, and cancels, the capacitive reactance of the antenna, so the loaded antenna presents a pure resistance to the transmission line and thereby prevents energy from being reflected. In the two-half loop antenna <NUM>, impedance loading can be achieved by use of one or more tuning elements <NUM>, <NUM> connected to the two-half loop antenna <NUM>. That is, the tuning elements <NUM>, <NUM> are interconnected with the conductor of the two-half loop antenna <NUM> In some embodiments, the tuning elements <NUM> may be one or more capacitors, as described further in description of <FIG>. In some embodiments, the tuning elements <NUM> may be inductors, as described further in description of <FIG>.

The tuning elements <NUM> can be connected in series with the two-half loop antenna <NUM>. In one implementation, the tuning elements <NUM> are approximately equally distributed across the first half loop <NUM> and the second half loop <NUM> of the two-half loop antenna <NUM>. In another implementation, the first half loop and the second half loop may be unequally loaded (for example by an adding an unequal number of tuning elements in the first half loop and the second half loop, or by using the same number of tuning elements in the first and second half loops but with unequal impedance values). Further, in yet another implementation the number of the tuning elements <NUM> in the first half loop and the second half loop may be different, however, the impedance value added to the first half loop and the second half loop may be approximately equal (by using tuning elements of different values in the first and second half loops). The number of tuning elements <NUM> and their respective values can be chosen based on the wavelength (λ) of the radio frequency signal to be transmitted or received through the two-half loop antenna <NUM>. Combinations of capacitors and/or inductors may be used as tuning elements with respective values selected to achieve a desired impedance. In one implementation, the tuning elements may be selected to achieve equal current distribution between the two half loops.

The total physical length of the two-half loop antenna <NUM> (i.e., the sum of the length of the first half loop and the second half loop) is less than (<NUM>/<NUM>)λ, i.e., less than three-fourths of the wavelength of the radio signal to be transmitted or received through the two-half loop antenna. The total electrical length of the two-half loop antenna <NUM> is one wavelength (λ). Therefore, from the perspective of the functioning of the two-half loop antenna <NUM>, the two-half loop antenna <NUM> antenna is equivalent to two half-wave loops fed in series with the radio frequency signal to be transmitted or received.

In some implementations, the tuning elements <NUM> are coils which are used to increase the electrical length of the two-half loop antenna <NUM> up to one wavelength (λ). In other implementations, the two-half loop antenna <NUM> may be loaded by a nearby dielectric structure, such as the PCB <NUM> or antenna holder <NUM>, inside the hearing aid component <NUM>, and the dielectric structure in combination with a loading due to a user's head, can contribute to increase in the electrical length of the two-half loop antenna <NUM> up to one wavelength (λ). For this reason, in certain situations the two-half loop antenna <NUM> may become electrically longer than one wavelength (λ). Therefore, in some implementations, due to such constraints, one or more capacitors may be used as the tuning elements <NUM>, as described further in <FIG>.

In one implementation, the physical antenna length of the two-half loop antenna <NUM> is less than one-half of the wavelength (λ) of the radio frequency signal to be transmitted or received through the two-half loop antenna <NUM>. The electrical length of the two-half loop antenna <NUM> in such implementation can be achieved to be approximately equal to the wavelength (λ) of the radio frequency signal to be transmitted through use of one or more tuning elements <NUM>.

In another implementation, the physical antenna length of the two-half loop antenna <NUM> is less than one-quarter of the wavelength (λ) of the radio frequency signal to be transmitted or received through the two-half loop antenna <NUM>. The electrical length of the two-half loop antenna <NUM> in such implementation can be achieved to be approximately equal to the wavelength (λ) of the radio frequency signal to be transmitted through use of one or more tuning elements <NUM>.

In yet another implementation, the physical antenna length of the two-half loop antenna <NUM> is less than three-quarters of the wavelength (λ) of the radio frequency signal to be transmitted or received through the two-half loop antenna <NUM>. For example, when the frequency of the radio signal to be transmitted or received through the two-half loop antenna <NUM> is <NUM>, the physical antenna length of the two-half loop antenna <NUM> can be less than <NUM>, and preferably in the range of <NUM> to <NUM>. The electrical length of the two-half loop antenna <NUM> in such implementation is achieved to be approximately equal to the wavelength (λ) of the radio frequency signal to be transmitted or received through use of one or more tuning elements <NUM>.

In one implementation, the choice of the tuning elements <NUM> with one or more desired values can be used to steer the radiation pattern of the two-half loop antenna <NUM>. For example, the choice of the value of the tuning elements <NUM> could be selected such that the first half loop is slightly more compensated than the second half loop of the two-half loop antenna <NUM> thereby allowing a slight steering of the radiation pattern. The steering of the radiation pattern is due to the slight mismatch of the input impedance of the first half loop and the second half loop of the two-half loop antenna <NUM>. Such steering of the radiation pattern of the two-half loop antenna <NUM> can be used to optimize the two-half loop antenna <NUM> for a certain architecture of the hearing aid component <NUM> (for example, design of the hearing aid component <NUM> with the two-half loop antenna <NUM> having a radiation pattern which is not symmetrical on the transverse plane).

In one implementation, the mid-point <NUM> and the feeding point <NUM> of the two-half loop antenna <NUM> are located on conductor segments which are orthogonal to a skin surface on which the hearing aid component <NUM> that includes the two-half loop antenna <NUM> is to be worn. The orthogonality of the conductor segments to the skin surface over which the two-half antenna <NUM> is to be worn allows communication between hearing aids placed at left and right sides of the head of a user. This allows the two-half loop antenna <NUM> to achieve a higher antenna gain and which could help in implementing solutions to reduce power consumption of the hearing aid component <NUM> due to a link with another device. In one implementation, the two-half loop antenna <NUM> has a radiation pattern such that the power radiated by the two-half loop antenna <NUM> is maximal on a horizontal plane radiating away from a user's head when worn by a user in an upright position.

In some implementations, the feeding point <NUM> of the two-half loop antenna <NUM> may not be exactly in the lateral center of the antenna PCB assembly <NUM>, but the feeding point <NUM> may be slightly shifted to the left or to the right of the antenna PCB assembly <NUM> to accommodate one or more design considerations of the hearing aid component <NUM>. The term "slightly shifted" signifies that the difference in location of the feeding point <NUM> is not significant enough to impact the operation of the two-half loop antenna <NUM>. The results obtained through simulations with the feeding point <NUM> "slightly shifted" resemble antenna radiation patterns with a design in which the feeding point <NUM> is in exact lateral center of the antenna PCB assembly <NUM>.

The two-half loop antenna <NUM> as described above provides several distinct advantages over traditional antenna design including requirement of reduced number of the tuning elements <NUM> in the two-half loop antenna <NUM> for tuning with respect to magnetic loop antennas. Further, an additional tuning element can be placed in parallel with the antenna <NUM> or one of the loops <NUM>, <NUM> to compensate for possible impedance mismatch in the two-half loop antenna <NUM> design. As illustrated, for example, the tuning element <NUM> is connected in parallel between the two half loops <NUM>, <NUM> and may comprise one or more capacitors. Additional series tuning elements can also be added, for example, in the transverse segments <NUM> of the first half loop and second half loop. The tuning elements <NUM>, <NUM> are further described below with reference to <FIG>.

Referring to <FIG>, the two-half loop antenna <NUM> comprises two loops fed in series with an RF signal as described above. The first half loop <NUM> of the two-half loop antenna <NUM> is a rectangular loop beginning at the feeding point <NUM> of the two-half loop antenna <NUM> and ending at the mid-point <NUM>. The second half loop <NUM> of the two-half loop antenna <NUM> is a rectangular loop beginning at the feeding point <NUM> of the two-half loop antenna <NUM> and ending at the mid-point <NUM>. The first half loop <NUM> and the second half loop <NUM> are in a lateral arrangement facing each other. Further, the first half loop <NUM> includes the first distal point <NUM> which lies between the coupling point <NUM> and the first inversion point <NUM>. The second half loop <NUM> includes the second distal point <NUM> which lies between the feeding point <NUM> and the second inversion point <NUM>.

The first distal point <NUM> and the second distal point <NUM> are separated by a separation distance such that magnetic flux generated due to current flowing through the first half loop <NUM> and magnetic flux generated due to current flowing through the second half loop <NUM> do not cancel the effect of each other. Current flowing through the first half loop <NUM> and the second half loop <NUM> refers to the current resulting from a radio frequency signal in the two-half loop antenna <NUM>. In a similar manner, the first inversion point <NUM> on the first half loop <NUM> and the second inversion point <NUM> on the second half loop <NUM> are separated by a separation distance such that the magnetic flux generated due to the current flowing through the first half loop <NUM> and the magnetic flux generated due to the current flowing through the second half loop <NUM> do not cancel the effect of each other.

In some embodiments, the first half loop <NUM> and the second half loop <NUM> may not necessarily be rectangular in shape, and may comprise another geometrical shape forming a loop, such as a square shape, circular shape, or oval shape. These shapes can include rounded corners and/or straight sides (as shown in the examples of <FIG>) such that they are not strictly rectangular, square, circular, or oval, but form a loop substantially conforming to such a shape. A diameter of the loop is a transverse dimension that does not necessarily imply that the shape is circular. The diameter of the first half loop <NUM> and the diameter of the second half loop <NUM> are approximately equal to one-half of the physical length of the two-half loop antenna <NUM>. The first half loop <NUM> and the second half loop <NUM> can be placed in a lateral arrangement on opposite sides of the hearing aid component <NUM>. The first half loop <NUM> and the second half loop <NUM> can be positioned opposite to each other such that each side of the first half loop <NUM> and each corresponding side of the second half loop <NUM> are laterally opposite to each other and are separated by a predetermined separation distance. In one implementation, the predetermined separation distance is at least the distance such that the magnetic flux generated due to the current flowing through the first half loop <NUM> and the magnetic flux generated due to the current flowing through the second half loop <NUM>, do not cancel the effect of each other.

<FIG> illustrates a current flow across the two-half loop antenna when a radio frequency signal is transmitted over the two-half loop antenna. <FIG> includes the two-half loop antenna <NUM> with the feeding point <NUM>, the mid-point <NUM>, the first half loop <NUM>, the first end section <NUM> of the first half loop, the second half loop <NUM>, the first end section <NUM> of the second half loop, the first inversion point <NUM> on the first half loop <NUM>, the second inversion point <NUM> on the second half loop <NUM>.

<FIG> illustrates a current flow through the first half loop <NUM> and the second half loop <NUM> of the two-half loop antenna <NUM>. A current flow occurs in the two-half loop antenna <NUM> when a radio frequency signal is coupled to the two-half loop antenna <NUM> through the feeding point <NUM> of the two-half loop antenna <NUM>. The current flow through the first half loop <NUM> and the second half loop <NUM> is illustrated with the help of solid arrows within the first half loop <NUM> and the second half loop <NUM>. The current flow in a segment of the first half loop <NUM> as compared to the current flow in a corresponding segment of the second half loop that faces the segment of the first half loop is in opposite direction as illustrated in <FIG>. The current distribution across the two-half loop antenna <NUM> can be analysed as a current profile with a half positive and half negative over the entire physical length of the two-half loop antenna <NUM>. The two-half loop antenna <NUM> also includes two inversion points, i.e., the first inversion point <NUM> in the first half loop <NUM>, and the second inversion point <NUM> in the second half loop <NUM>. The first inversion point <NUM> is at the farthest distance or diagonally across from the first end section <NUM> of the first half loop <NUM>. Similarly, the second inversion point <NUM> is at the farthest distance or diagonally across from the first end section <NUM> of the second half loop <NUM>. The first inversion point <NUM> and the second inversion point <NUM> correspond to zero-crossing points of current in a one full-wavelength of a radio-frequency signal that exists over the two-half loop antenna <NUM>, when the radio-frequency signal is transmitted over the two-half loop antenna <NUM>. The antenna segments of the two-half loop antenna <NUM> that have the highest amplitude of current (corresponding to the radio frequency signal being transmitted through the two-half loop antenna <NUM>) are the transverse segments <NUM> of the first half loop and the second half loop.

The above described geometry of the two-half loop antenna <NUM> allows the antenna impedance to be relatively small. In one implementation, the antenna impedance is less than 200Ω. Further, the radiation pattern of the two-half loop antenna <NUM> is a direct consequence of the geometry of the two-half loop antenna <NUM> as described above. The radiation pattern of the two-half loop antenna <NUM> is very similar to a half-wave loop rather than to a full-wave antenna. Such radiation pattern is a result of the transverse segments of the first half loop <NUM> and the second half loop <NUM> being close to the feeding point <NUM>. Radiating nulls in the radiation pattern of the two-half loop antenna <NUM> are smoother than radiation pattern of similar traditional antennas. The radiation pattern of the two-half loop antenna <NUM> renders an important advantage to keep the efficiency of the two-half loop antenna <NUM> high when the structure of the two-half loop antenna <NUM> is integrated into the hearing aid component <NUM> and worn on an ear.

In one implementation, with a <NUM> width, <NUM> long copper track of the two-half loop antenna <NUM>, onto a <NUM> polyimide substrate a natural resonance around <NUM> in free space was obtained with a low impedance at feeding = (<NUM> + j*<NUM>) Ω. In this implementation, the radiation pattern of two-half loop antenna <NUM> in free space includes multiple roots. The radiation pattern is partly defined by the half-wave loops, and partly by the two-half loop antenna <NUM> seen as a folded dipole. This gives an almost isotropic radiation pattern to the two-half loop antenna <NUM>, with the main lobe at <NUM> dBi and the radiation nulls at -<NUM> dBi.

As compared to currently used magnetic loop antennas, the two-half loop antenna <NUM> shows a <NUM> dB improvement in efficiency as per simulation results. In the polar cuts a gain of more than <NUM> dB is visible towards the backside (i.e., towards a user's ear). Further, the radiation pattern around a user's head as per simulation results indicates that more energy is obtained as compared to other similar hearing devices in case of binaural communication.

<FIG> illustrates a circuit diagram of the two-half loop antenna with tuning elements added to compensate the physical length of the two-half loop antenna <NUM> to be approximately equal to the wavelength of the radio frequency signal is transmitted over the two-half loop antenna <NUM>. <FIG> includes the radio frequency transceiver <NUM>, capacitors <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, the feeding lines <NUM>, the feeding point <NUM>, and the two-half loop antenna <NUM>. The capacitors <NUM>, <NUM> (at the mid-point), <NUM>, <NUM>, and <NUM> illustrate one implementation of the tuning elements <NUM> (described above in <FIG>). The tuning element <NUM> connected in parallel at the feeding point between the two half loops illustrates one implementation of the tuning element <NUM> (described above in <FIG>). <FIG> illustrates a schematic top view of the two-half loop antenna <NUM> and also illustrates the physical antenna length of the two-half loop antenna <NUM> as described above.

In one implementation, the two-half loop antenna <NUM> may be loaded by the nearby dielectric structure inside the hearing aid component <NUM> or by the dielectric structure in combination with a loading due to a user's head on which the hearing aid component is to be worn. The loading of the two-half loop antenna <NUM> by the combination of the dielectric structure along with the user's head may result in an increase in the electrical antenna length of the two-half loop antenna <NUM> greater than one wavelength (λ) of the radio frequency signal to be transmitted through the two-half loop antenna <NUM>. Therefore, in order to compensate the electrical length of the two-half loop antenna <NUM>, capacitors <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may be used to decrease the electrical length of the two-half loop antenna <NUM> to match up to the wavelength (λ) of the radio frequency signal to be transmitted through the two-half loop antenna <NUM>, as illustrated in <FIG>.

One or more tuning elements (i.e., the capacitors <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM> in <FIG>) are used to adjust the antenna impedance of the two-half loop antenna <NUM> to match the impedance set up by the radio frequency transceiver <NUM>. Further, <FIG> illustrates the two-half loop antenna <NUM> being tuned with one parallel component (capacitor <NUM>) and five series components (i.e., capacitors <NUM>, <NUM>, <NUM>, <NUM> and <NUM>). In some implementations, fewer or greater number of capacitors may be utilized for adjusting the impedance of the two-half loop antenna <NUM>.

<FIG> illustrates a circuit diagram of the two-half loop antenna with tuning elements added to compensate the physical length of the two-half loop antenna <NUM> to be approximately equal to the wavelength of the radio frequency signal is transmitted over the two-half loop antenna <NUM>. <FIG> includes the radio frequency transceiver <NUM>, inductors <NUM>, <NUM> (at the mid-point), <NUM>, <NUM>, <NUM> and <NUM>, the feeding lines <NUM>, the feeding point <NUM>, and the two-half loop antenna <NUM>. The inductors <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM> illustrate one implementation of the tuning elements <NUM> (described above in <FIG>). The tuning element <NUM> connected in parallel at the feeding point between the two half loops illustrates one implementation of the tuning element <NUM> (described above in <FIG>). <FIG> illustrates a schematic top view of the two-half loop antenna <NUM> and also illustrates the physical antenna length of the two-half loop antenna <NUM> as described above.

In one implementation, the two-half loop antenna <NUM> has a physical length with a value smaller than one-half of the wavelength (λ) of the radio frequency signal to be transmitted over the two-half loop antenna <NUM>. Therefore, in order to make the electrical length of the two-half loop antenna <NUM> approximately equal to the wavelength (λ) of the radio frequency signal to be transmitted, inductors <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may be used to increase the electrical length of the two-half loop antenna <NUM> to match up to the wavelength (λ) of the radio frequency signal to be transmitted through the two-half loop antenna <NUM>, as illustrated in <FIG>.

Claim 1:
A hearing device component comprising:
a wireless communication unit (<NUM>); and
an antenna including a two-half loop antenna (<NUM>), wherein the two-half loop antenna comprises:
a conductor and one or more interconnected tuning elements (<NUM>) defining a first half loop (<NUM>) and a second half loop (<NUM>) configured to be fed in series with a wireless signal from the wireless communication unit, wherein the first half loop and the second half loop comprise respective half loops of the two-half loop antenna;
the first half loop comprising a first end section (<NUM>) of the first half loop, wherein
the first end section of the first half loop is coupled to the wireless communication unit;
the second half loop comprising a second end section (<NUM>) of the second half loop,
wherein the second end section of the second half loop is coupled to the wireless communication unit;
respective transverse segments (<NUM>) of the first half loop and second half loop join the first half loop and the second half loop at a mid-point (<NUM>) of the two-half loop antenna;
wherein a physical antenna length of the two-half loop antenna is less than ¾ of a wavelength of the wireless signal to be transmitted or received through the two-half loop antenna and wherein an electrical length of the two-half loop antenna is approximately equal to the wavelength of the wireless signal to be transmitted or received;
wherein the hearing device component further comprises feeding lines (<NUM>, <NUM>) connecting the wireless communication unit to a feeding point (<NUM>) at the first end section (<NUM>) of the first half loop (<NUM>) and the second end section (<NUM>) of the second half loop (<NUM>);
wherein a distance between the feeding point (<NUM>) of the two-half loop antenna (<NUM>) and the mid-point (<NUM>) of the two-half loop antenna is in a range of <NUM> to ¼ of a distance between the feeding point and a farthest point (<NUM>) defined by a point at which an axial line (<NUM>) through the feeding point and the mid-point intersects a plane (<NUM>) perpendicular to the axial line and intersecting a point on the two-half loop antenna farthest from the feeding point, and
wherein the mid-point is located between the feeding point and the farthest point.