Abstract:
A speaker is provided in which both audio signals and radio frequency (RF) signals are simultaneously fed to the coil of a speaker device causing the coil to drive the speaker&#39;s membrane producing sound and operate as an antenna for various electromagnetic frequencies. The speaker can be equipped with appropriate filter circuits to isolate the audio signals and RF signals within the speaker device.

Description:
TECHNICAL FIELD 
       [0001]    This application relates to speakers and, more specifically integrating antenna with speakers. 
       BACKGROUND OF THE INVENTION 
       [0002]    An antenna is a transducer that converts electrical signals on a device to radiated electromagnetic waves and vice-versa. It&#39;s dimensions, geometry, surrounding materials and the method of connections dictate the frequency range(s) (band(s)) in which the antenna works well (i.e. where the antenna resonates). 
         [0003]    Speakers and receivers are devices that convert electrical signals into sound energy. Generally speaking, a speaker or receiver receives an electrical signal and converts the electrical signal into sound energy for presentation to the listener. 
         [0004]    Speakers and receivers are often used in proximity to antennas in the same electronic device. For example, in cellular phones there is a speaker or receiver that presents sound to the ear of a listener. There are also antennas by which the cellular phone makes transmissions from the cellular phone to a cellular and/or other networks and vice versa (e.g., Bluetooth or WIFi networks). Personal computers, laptops, wearable device, and tablets also may have both speakers and antennas. 
         [0005]    Speakers and receivers have been viewed as a hindrance to antenna performance. To mitigate the effect on antenna performance, speakers/receivers have either been kept at a distance from antennas or have been electrically choked by the use of inductors in their audio paths. These inductors allow low frequency signals (such as audio signals) to pass through almost perfectly intact but block radio frequency (RF) signals from crossing over from the speaker/receiver to the printed circuit board (PCB) or vice-versa. From the antenna&#39;s point of view, the speaker/receiver thus appears to be disconnected from the rest of the PCB and this improves the antenna&#39;s performance. 
         [0006]    However, these approaches may increase system cost and result in larger devices. The problems of previous approaches have resulted in some user dissatisfaction with these previous approaches. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    For a more complete understanding of the disclosure, reference should be made to the following detailed description and accompanying drawings wherein: 
           [0008]      FIG. 1  comprises a side-cutaway view of a speaker according to various embodiments of the present invention; 
           [0009]      FIG. 2  comprises a bottom view of a speaker according to various embodiments of the present invention; 
           [0010]      FIG. 3  comprises a diagram of a speaker used with a printed circuit board (PCB), the PCB having additional circuitry according to various embodiments of the present invention; 
           [0011]      FIG. 4  comprises a diagram of a speaker used with a dielectric according to various embodiments of the present invention; 
           [0012]      FIG. 5  comprises a speaker used in a speaker box according to various embodiments of the present invention. 
       
    
    
       [0013]    Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity. It will further be appreciated that certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required. It will also be understood that the terms and expressions used herein have the ordinary meaning as is accorded to such terms and expressions with respect to their corresponding respective areas of inquiry and study except where specific meanings have otherwise been set forth herein. 
       DETAILED DESCRIPTION 
       [0014]    The present approaches utilize the coil in speakers/receivers as the antenna element. The speaker/receiver&#39;s coil may either form a part of a larger antenna or the entire antenna element itself. It may be used either in part or wholly as any type of antenna including but not limited to loop antennas, multi-turn loop antennas, helical antennas, or other examples of antennas. 
         [0015]    In the present approaches, the coil of the speaker or receiver acts simultaneously (at the same time) as both a part of an acoustic transducer (its movement enables the generation of sound waves) as well as an antenna (radiating electromagnetic signals). To avoid electromagnetic signals (generally at higher frequencies) from going to the audio circuits and to avoid audio signals (generally at lower frequencies) from going to the electromagnetic circuits, filtering in each path is implemented. 
         [0016]    In other aspects, various approaches are used to allow the coil of a speaker to resonate at any RF frequency range desired (such as those used in mobile phone communications—Bluetooth, WI-Fi, 3G, 2G, GSM, CDMA, LTE, to mention a few examples). Other examples are possible. 
         [0017]    In one approach, the receiver&#39;s metallic composition is changed (changing the permeability of the material can result in a change in the coil&#39;s resonant frequency). 
         [0018]    In another aspect, the size/shape/geometry of receiver coil is adjusted to make the receiver resonate at desired frequency. 
         [0019]    In still another example, electrical circuits (e.g., involving the use of inductors, capacitors, resistors, impedance matching circuits, to mention a few examples) are either embedded in the receiver coil or connected to it (e.g. on a PCB) to adjust the resonance frequency of the coil and/or its radiation performance (efficiency). 
         [0020]    In yet other aspects, switches (including but not limited to electronic, electrical, mechanical, MEMs switches), variable antenna matching circuits, or some combination of these may also be used to tune the resonant characteristics of the receiver to help it resonate across or within bands of interest. 
         [0021]    In still other approaches, the receiver is placed next to a dielectric material (including but not limited to different plastics, ceramics, to mention a few examples) may also be used to alter the frequencies at which the receiver antenna can radiate. In one example, the membrane is made of a dielectric material and this composition has an effect on the resonant frequency of the antenna. The receiver/speaker may also be disposed in an assembly (such as in an integrated speaker assembly/box or an integrated receiver assembly/box). 
         [0022]    In still other examples, the spatial location where the RF signal is fed onto the speaker/receiver coil and where a connection to ground is located are adjusted to adjust the frequency. 
         [0023]    As used herein, the terms speakers and receivers are henceforth used interchangeably. 
         [0024]    Referring now to  FIG. 1 , a speaker (or receiver)  100  includes a top plate  101 , a pot or yoke  102 , a speaker coil  104 , speaker coil leads  105  (where RF and audio signals are fed), a magnet  106 , a basket  107 , a membrane  108  including a torous  110  and a dome  112 , and a cover  120 . An audio circuit  132  is connected to a low pass filter  134 . An RF circuit  136  is connected to a high pass filter  138 . This RF circuit can supply RF signals to be radiated, receive and process RF signals captured by the antenna or both. 
         [0025]    The magnet  106  is used to produce a magnetic field. The top plate  101  is used to direct the magnetic flux. The coil is attached to a membrane  108  which is constructed of some flexible material. The pot  102  or yoke is constructed of a magnetic permeable material, for example, steel. The speaker coil  104  receives electrical signals via the speaker coil leads  105  including audio and RF signals. The basket  107  is used to enclose the other components. The cover  120  couples to the basket and further encloses the components. 
         [0026]    The audio circuit  132  produces audio signals in the audio frequency range, for example 20 to 20 kHz (it can be extended further to the ultrasonic or lower into the infrasonic range). The low pass filter  134  is used to pass low frequencies below a predetermined low cutoff frequency but prevents signals at higher frequencies above the low cut-off frequency from flowing through. 
         [0027]    The RF circuit  136  produces RF signals that are to be transmitted via an antenna to another entity, and also processes RF signals received via the antenna for example, in the cellular/WiFi/Bluetooth frequency range. The high pass filter  138  passes frequencies above a high cut-off frequency and prevents signals at frequencies below the high cut-off frequency from flowing through. 
         [0028]    The coil  104  acts simultaneously as both a part of an acoustic transducer (its movement enables the generation of sound waves) as well as an antenna (radiating electromagnetic signals). In these regards, the RF circuit  136  sends electrical signals that pass through the high pass filter  138  to the coil  104  via speaker coil leads  105 . Similarly, RF signals received by the coil  104  from an external source pass through the high pass filter  138  and get sent to the RF circuit  136 . At the same time, the audio circuit  132  transmits other electrical signals through the low pass filter  134  to the coil  104  via speaker coil leads  105 . Simultaneously, the electrical signals from the RF circuit  136  radiate from the coil  104 , and the electrical signals from the audio circuit  132  cause a changing magnetic field moving the coil  104 . The coil  104  is attached to the membrane  108  and consequently movement of the coil  104  moves the membrane  108  up and down in the direction of the arrow labeled  117 . Movement of the membrane  108  creates sound, which can be presented to a user. 
         [0029]    To avoid electromagnetic signals (generally at higher frequencies) from going to/reaching the audio circuit  132 , the low pass filter  134  filters out high frequency signals originating at the RF circuit  136  and blocks these signals from reaching the audio circuit  132 . To avoid audio signals (generally at lower frequencies) from going to/reaching the RF (electromagnetic) circuit  136 , the high pass filter  138  filters out low frequency signals originating at the audio circuit  132  and blocks these signals from reaching the RF circuit  136 . 
         [0030]    In other aspects, the metallic composition of the speaker  100  (e.g., any component of the speaker  100  such as the basket  107 ) is changed (e.g., changing the permeability of the material can result in a change in the resonant frequency of the coil  104 ). Using a higher permeability material can help lower the frequency at which the coil resonates efficiently as an antenna. 
         [0031]    In another aspect, the size/shape/geometry of the coil  104  is adjusted to make the receiver resonate at desired frequency. In general, using a coil with a larger perimeter will result in a lowering of its resonant frequency. 
         [0032]    In still another example, electrical circuits (e.g., involving the use of inductors, capacitors, resistors, impedance matching circuits, to mention a few examples) are either embedded in the receiver coil  104  or connected to it to adjust the resonance frequency of the coil  104  or to improve its radiation capability. 
         [0033]    Referring now to  FIG. 2 , the bottom of the speaker pot  102  is described. As shown a first coil speaker lead  202  and a second speaker coil lead  204  extend through openings in the pot  102 . The first coil speaker lead  202  may be an audio signal (from the audio circuit  132 ) and the RF feed from the RF circuit  136  after appropriate filtering. The second speaker coil lead  204  may be an audio signal (from the audio circuit  132 ) and RF ground after appropriate filtering. The signals over leads  202  and  204  may be swapped. 
         [0034]    In still other examples, the spatial location where the RF signal is fed onto the speaker/receiver coil and where a connection to ground is located are adjusted to adjust the frequency. 
         [0035]    Referring now to  FIG. 3 , one example of circuitry used on a PCB is described. A speaker  300  is coupled to an RF feed and audio lead or line  302  and an RF ground and audio lead or line  304 . The leads  302  and  304  connect to a printed circuit board (PCB)  306 . The speaker  300  operates as described above with respect to speaker  100  described with respect to  FIG. 1 . 
         [0036]    The PCB  306  includes two impedance matching circuits  308  and  310 , a switch  312  to switch between the two matching circuits, a filtered RF signal  314  (that has been filtered to include high frequencies above a high cut-off frequency), a filtered low pass audio signal  316  (that has been filtered to include high frequencies above a high cut-off frequency), and a high pass filter  318 . The signal  316  originates from an audio circuit (not shown) while the signal  314  originates from an RF circuit (not shown). The signal  314  is to be broadcast using the coil of the speaker  300  as an antenna, and simultaneously the signal  316  is used by the speaker  300  to produce audio sound for a listener. In some aspects, RF signals can also be received by the coil which converts them to electrical signals that can be processed by RF receivers. In such cases,  314  can also represent an RF receiver. 
         [0037]    The circuits  308  and  310  may include various combinations of fixed or variable inductors, capacitors, resistors, or other impedance matching components to mention a few examples. Other examples are possible. The switch  312  may be used to select from the impedance matching circuits  308  or  310  to make the antenna (coil) resonate at different frequencies. Any number of impedance matching circuits may be used. The various components can be used to provide various functions such as matching the impedance of the antenna with that of the RF circuitry. Other examples of functions are possible. 
         [0038]    Referring now to  FIG. 4 , one example of a speaker used as part of a speaker box is described. A speaker  400  is coupled to an RF feed and audio lead or line  402  and an RF ground and audio lead or line  404 . The leads  402  and  404  are connected to a printed circuit board (PCB)  406 . The speaker  400  operates as described above with respect to speaker  100  of  FIG. 1 . 
         [0039]    The speaker  400  is placed next to a dielectric material  408  (including but not limited to different plastics, ceramics, to mention a few examples) and this configuration is effective to alter the frequencies at which the receiver antenna (the coil of the speaker  400 ) can radiate effectively. 
         [0040]    Referring now to  FIG. 5 , one example of a speaker  500  in a speaker box  508  is described. The speaker  500  is disposed in a speaker box  508 . An RF feed and audio lead or line  502  and an RF ground and audio lead or line  504  couple to the speaker. The leads  502  and  504  are connected to a printed circuit board (PCB)  506 . The speaker  500  operates as described above with respect to speaker  100  of  FIG. 1 . 
         [0041]    The box  508  (or integrated assembly) may be used to hold other components such as antenna extensions. By integrated receiver assembly (or box), it is meant a receiver that is substantially integrated into an assembly or housing. The box  508  may be constructed in one example of plastic. Other examples of materials or combinations of materials may also be used. 
         [0042]    Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. It should be understood that the illustrated embodiments are exemplary only, and should not be taken as limiting the scope of the invention.