PATENT DOCUMENT

Publication Number: US-9866945-B2
Application Number: US-201614993548-A
Country: US
Kind Code: B2

Title: Antennas for wireless earbuds

Abstract:
An accessory such as a wireless earbud may have an antenna for transmitting and receiving wireless signals. A housing for the earbud may have a main body portion and an extended portion that forms a stalk protruding from the main body portion. The earbud may have a speaker aligned with a speaker port in the main body portion. The antenna may have an elongated shape and may extend along the stalk. The stalk may have a plastic housing wall portion. The antenna may be formed from first and second metal traces on opposing sides of a printed circuit substrate. The first metal trace may form an antenna resonating element arm and may lie between the substrate and the plastic housing wall portion. The second metal trace may be a ground trace. A feed for the antenna may be located at a juncture between the main body portion and the stalk.

Claims:
What is claimed is: 
     
       1. An earbud, comprising:
 a housing having a main body portion with a speaker port and having a stalk that extends from the main body portion; 
 a speaker mounted in the main body portion in alignment with the speaker port; 
 a printed circuit substrate; and 
 an antenna in the stalk, wherein the antenna comprises a metal trace on the printed circuit substrate, a transmission line is coupled to the metal trace through a via in the printed circuit substrate, the via is configured to pass antenna signals from a positive signal path of the transmission line to the metal trace, the positive signal path comprises a conductive line extending into the printed circuit substrate, the conductive line and the metal trace are formed in parallel planes, and the via is interposed between the conductive line and the metal trace. 
 
     
     
       2. The earbud defined in  claim 1  wherein the antenna has an elongated shape and extends along the stalk. 
     
     
       3. The earbud defined in  claim 2  wherein the antenna comprises an inverted-F antenna. 
     
     
       4. The earbud defined in  claim 3  wherein the stalk has a plastic housing wall portion, wherein the earbud further comprises a conductive component in the stalk, and wherein the antenna is interposed between the conductive component and the plastic housing wall portion. 
     
     
       5. The earbud defined in  claim 4  wherein the printed circuit substrate is adjacent to the plastic housing wall portion, and the antenna includes an additional metal trace on the printed circuit substrate that is adjacent to the conductive component. 
     
     
       6. The earbud defined in  claim 5  wherein the metal trace comprises a resonating element arm and wherein the additional metal trace comprises an antenna ground. 
     
     
       7. The earbud defined in  claim 6  wherein the antenna further comprises a return path via that passes through the printed circuit substrate between the resonating element arm and the antenna ground. 
     
     
       8. An electronic device, comprising:
 a dielectric housing having a main body portion with a port and having an elongated protruding portion that extends from the main body portion along a longitudinal axis; and 
 an electrical component aligned with the port; and 
 an antenna in the dielectric housing that extends along the longitudinal axis within the elongated protruding portion, wherein the antenna comprises an antenna ground and first and second ground feed terminals that are coupled to the antenna ground at respective first and second locations, wherein the elongated antenna comprises a substrate having first and second opposing surfaces, a first metal trace on the first surface, and a second metal trace on the second surface. 
 
     
     
       9. The electronic device defined in  claim 8  wherein the elongated protruding portion is characterized by a length, a width, and a length to width ratio of at least three. 
     
     
       10. The electronic device defined in  claim 9  wherein the electrical component comprises a speaker and wherein the main body portion is configured to be received within an ear of a user. 
     
     
       11. The electronic device defined in  claim 10  wherein the antenna comprises an inverted-F antenna having a resonating element arm that extends along the elongated protruding portion. 
     
     
       12. The electronic device defined in  claim 8  further comprising a return path via that extends through the substrate from the first metal trace to the second metal trace. 
     
     
       13. The electronic device defined in  claim 12  wherein the electrical component comprises a speaker and wherein the main body portion is configured to be received within an ear of a user. 
     
     
       14. A wireless earbud, comprising:
 a speaker; 
 an inverted-F antenna; and 
 a housing having a main body portion in which the speaker is mounted and having a stalk that protrudes from the main body portion in which the inverted-F antenna is mounted, wherein the inverted-F antenna includes a resonating element arm within the stalk and an antenna ground that includes a first portion within the stalk and a second portion within the main body portion of the housing. 
 
     
     
       15. The wireless earbud defined in  claim 14  wherein the inverted-F antenna comprises a dielectric substrate having first and second surfaces, a first metal trace on the first surface, and a second metal trace on the second surface. 
     
     
       16. The wireless earbud defined in  claim 15  further comprising a return path via that passes through the dielectric substrate from the first metal trace to the second metal trace. 
     
     
       17. The wireless earbud defined in  claim 16  further comprising a battery in the housing, wherein the stalk comprises a plastic wall that lies adjacent to the first metal trace. 
     
     
       18. The wireless earbud defined in  claim 14  wherein the main body portion is coupled to the stalk at a juncture in the housing and wherein the inverted-F antenna has a feed at the juncture.

Description:
BACKGROUND 
     This relates generally to electronic devices and, more particularly, to electronic devices with wireless circuitry. 
     Electronic devices such as electronic accessories for cellular telephones, computers, and other electronic equipment often include wireless circuitry. For example, earbuds are available that communicate wirelessly with cellular telephones and other equipment. 
     Challenges can arise in implementing wireless communications circuitry in a compact device such as an earbud. If care is not taken, antennas will not perform effectively. This can make it difficult or impossible to achieve desired levels of wireless communications performance. 
     It would therefore be desirable to be able to provide devices such as earbuds with improved wireless circuitry. 
     SUMMARY 
     An accessory such as a wireless earbud may have an antenna for transmitting and receiving wireless signals. The accessory may have a housing with a main body portion and an extended portion that protrudes outwardly from the main body portion. The main body portion may have a speaker port. A speaker for the earbud may be mounted in the main body portion in alignment with the speaker port. The extended portion may form a stalk that protrudes from the main body portion and that may be grasped by a user when inserting and removing the earbud from the user&#39;s ear. 
     The antenna of the earbud may have an elongated shape and may extend along the stalk. The stalk may have a plastic housing wall that surrounds the antenna. 
     The antenna may be formed from first and second metal traces on opposing sides of a printed circuit substrate. The first metal trace may form an antenna resonating element arm and may lie between the substrate and the plastic housing wall of the stalk. The second metal trace may be a ground trace. 
     The antenna may be an inverted-F antenna. A return path via may pass through the printed circuit substrate of the antenna from the first to the second metal trace. The antenna may have a feed that is coupled to a transmission line. The feed may be located at a juncture between the main body portion and the stalk. 
     Further features will be more apparent from the accompanying drawings and the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of an illustrative electronic device with wireless circuitry in accordance with an embodiment. 
         FIG. 2  is a diagram of an illustrative antenna of the type that may be used in an electronic device in accordance with an embodiment. 
         FIG. 3  is a front perspective view of an illustrative earbud in accordance with an embodiment. 
         FIG. 4  is a rear perspective view of the illustrative earbud of  FIG. 3  showing where an antenna may be located in the earbud accordance with an embodiment. 
         FIG. 5  is a top view of an illustrative printed circuit with traces that form an antenna in accordance with an embodiment. 
         FIG. 6  is a side view of the illustrative antenna of  FIG. 5  in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     An electronic device of the type that may be provided with wireless circuitry is shown in  FIG. 1 . Device  10  of  FIG. 1  may be a wireless accessory such as a wireless earbud or other small portable accessory of the type that is used in conjunction with another electronic device such as a cellular telephone, portable computer, watch, media player, or other host equipment. If desired, device  10  may be a different type of electronic equipment. Configurations in which device  10  is a wireless accessory may sometimes be described herein as an example. 
     Devices such as device  10  may communicate wirelessly with external electronic equipment over a wireless communications link. The wireless communications link may be a cellular telephone link (e.g., a wireless link at frequencies of 700 MHz to 2700 MHz or other suitable cellular telephone frequencies), may be a wireless local area network link operating at 2.4 GHz, 5 GHz, or other suitable wireless local area network frequencies, may be a Bluetooth® link operating at 2.4 GHz, may involve millimeter wave communications, may involve near-field communications, or may involve wireless communications in other communications bands. Configurations in which device  10  operates at 2.4 GHz to support short-range communications such as Bluetooth® communications may sometimes be described herein as an example. 
     As shown in  FIG. 1 , device  10  (e.g., an earbud or other accessory) may include control circuitry such as storage and processing circuitry  16 . Storage and processing circuitry  16  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  16  may be used to control the operation of device  10 . This processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processor integrated circuits, application specific integrated circuits, etc. 
     Storage and processing circuitry  16  may be used to run software on device  10 . 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  10 , to start or stop audio playback, etc.), and may handle other device operations. To support interactions with external equipment, storage and processing circuitry  16  may be used in implementing communications protocols. Communications protocols that may be implemented using storage and processing circuitry  30  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, etc. 
     Device  10  may include microphones, speakers, tone generators, and other audio components (see, e.g., speaker  20 ). Microphones may gather ambient noise signals for noise cancellation functions. Speakers may play back sound for a user. Tone generators and other sound output devices may generate other audible output. Sensors and other components  22  in device  10  may include proximity sensors (e.g., capacitive proximity sensors, light-based proximity sensors, etc.), force sensors, buttons, magnetic sensors, accelerometers and other components for measuring device orientation and/or motion, strain gauge sensors, vibrators, etc. Control circuitry  16  may use input-output circuitry such as speaker  20  and/or sensors and other components  22  to gather input from a user and/or the environment surrounding device  10 . In response, control circuitry  16  may transmit wireless signals to remove equipment and may provide a user with audible, visible, and tactile output 
     Device  10  may include battery  26  to provide power to the circuitry of device  10 . Battery  26  may be, for example, a rechargeable battery. Battery  26  may be recharged wirelessly (e.g., by providing device  10  with wireless power) or may be recharged via a wired connection between external equipment and device  10 . Configurations in which battery  26  is not rechargeable (e.g., in which battery  26  is a replaceable non-rechargeable battery) may also be used. 
     Electronic device  10  may include wireless circuitry for supporting wireless communications with external equipment. The wireless circuitry may include radio-frequency transceiver  24  and one or more antennas such as antenna  40 . Antenna  40  may have a feed that includes positive antenna feed terminal  98  and ground antenna feed terminal  100 . Transmission line  92  may be used to couple radio-frequency transceiver circuitry  24  to antenna  40 . Transmission line  92  may have a positive signal path such as line  94  and a ground signal path such as line  96 . Transmission lines in circuitry  10  such as transmission line  92  may include coaxial cable paths, microstrip transmission lines, stripline transmission lines, edge-coupled microstrip transmission lines, edge-coupled stripline 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. 
     Antenna  40  may be formed using any suitable antenna type. For example, antenna  40  may be an antenna with a resonating element that is formed from a loop antenna structure, a patch antenna structure, an inverted-F antenna structure, a slot antenna structure, a planar inverted-F antenna structure, a helical antenna structure, a monopole, a dipole, hybrids of these designs, etc. If desired, antenna  40  may include tunable circuitry and control circuitry  16  may be used to select an optimum setting for the tunable circuitry to tune antenna  40 . Antenna adjustments may be made to tune antenna  40  to perform in a desired frequency range or to otherwise optimize antenna performance. Sensors may be incorporated into antenna  40  or elsewhere in device  10  to gather sensor data in real time that is used in adjusting antenna  40 . Antenna  40  may also be implemented using a fixed (non-tunable) configuration. 
     An illustrative configuration for antenna  40  is shown in  FIG. 2 . In the example of  FIG. 2 , antenna  40  is an inverted-F antenna and has inverted-F antenna resonating element  100  and antenna ground  102 . Antenna  40  may be fed by coupling transmission line  92  ( FIG. 1 ) to antenna feed  108 . Antenna feed  108  has positive antenna feed terminal  98  coupled to resonating element arm  104  of antenna resonating element  100  and has ground antenna feed  100  coupled to ground  102 . Return path  106  (i.e., a short circuit path) may be coupled between antenna resonating element arm  104  and ground  102  in parallel with feed  108 . 
     Antenna ground  102  may be formed from ground traces in a printed circuit or other substrate, metal portions of a battery, metal housing structures, metal portions of internal device components, or other conductive ground structures in device  10 . Antenna resonating element  100  may be formed from metal printed circuit traces and/or other conductive structures in device  10  (e.g., metal foil, metal housing structures, portions of internal device components, etc.). 
     A perspective view of device  10  in an illustrative configuration in which device  10  is a wireless earbud is shown in  FIG. 3 . As shown in  FIG. 3 , earbud  10  may have a front  10 F and a rear  10 R. Housing  12  may have a main portion such as main body portion  12 B in which speaker port  122  is formed. Speaker port  122  may face the front of earbud  10  (i.e., port  122  may be formed in the surface of housing  12  at front  10 F of earbud  10 ). An elongated protruding portion such as housing stalk portion  12 T may extend outwardly from main housing portion  12 B. 
     Main body portion  12 B may have a shape that fits within the ear of a user. Speaker  20  may be mounted in main body portion  12 B and may be aligned with speaker port  122 . Speaker  20  may be used to provide sound to the ear of the user. Speaker port  122  may be formed from one or more openings in housing  12 . One or more plastic or metal mesh layers may be interposed between speaker  20  and the opening(s) in housing  12  (e.g., to help prevent the intrusion of dust and other contaminants into speaker  20 ). 
     Housing  12  may be formed from metal, plastic, carbon-fiber composite material or other fiber composites, glass, ceramic, other materials, or combinations of these materials. Stalk  12 T may be characterized by a length L and a diameter D (or other lateral dimension such as a width perpendicular to length L). The aspect ratio (L/D) of stalk  12 T may be high (e.g., at least three, at least four, at least five, at least ten, less than 20, etc.). The elongated shape of stalk  12 T may help allow a user to grasp earbud  10  when removing earbud  10  from the ear or when placing earbud  10  in the ear. Stalk  12 T may extend from main body portion  12 B at rear  10 R of housing  12  and may extend along longitudinal stalk axis  120 . If desired, stalk  12 T may have a curved shape. The illustrative straight shape of  FIG. 3  is merely illustrative. 
     A rear perspective view of earbud  10  of  FIG. 3  is shown in  FIG. 4 . As shown in  FIG. 4 , antenna  40  may have an elongated shape that runs along axis  120  parallel to the length of stalk  12 T. Antenna  40  may extend along stalk  12 T from feed  108  toward tip  12 T′ of stalk  12 T. 
     Antenna  40  may, if desired overlap structures such as battery  26  and other conductive components that are located in interior region  124  of housing  12 . These structures may contain conductive materials that tend to shield antenna  40 . To ensure that antenna  40  operates satisfactorily, antenna  40  may run under a plastic stalk wall or other dielectric wall in housing  12  (i.e., just under the surface of housing  12  in stalk  12 T), so that antenna resonating element arm  104  of antenna  40  is interposed between the battery and other conductive structures in region  124  and the dielectric housing wall. The battery and other conductive structures in region  124  may form part of antenna ground  102 . 
     Antenna feed  108  may be located at juncture  12 J of housing  12  between main body portion  12 B and stalk  12 T, rather than at a location that overlaps region  124  in main body portion  12 B. Locating the antenna feed in location  108  of  FIG. 4  at juncture  12 J rather than other locations such as location  108 ′ may help to minimize currents in battery  26  and other ground plane currents that might reduce antenna efficiency. 
     Antenna  40  may be formed from patterned metal traces on a printed circuit. The printed circuit may be a rigid printed circuit board (e.g., a printed circuit formed from a rigid printed circuit board substrate material such as fiberglass-filled epoxy) or may be a flexible printed circuit (e.g., a printed circuit formed from a flexible layer of polyimide or a sheet of other polymer substrate material). 
       FIG. 5  is a top view of an illustrative configuration for antenna  40  in which antenna  40  is formed from a printed circuit substrate. As shown in  FIG. 5 , antenna  40  may be formed from metal antenna traces on printed circuit substrate  130  such as metal traces that form antenna resonating element arm  104 . Antenna  40  may be fed using transmission line  92 . Transmission line  92  may include positive signal line structures such as conductive line  94 , which is coupled to positive feed terminal  98  of feed  108  and ground signal conductors such as conductor(s)  106 , coupled to ground feed terminal  100  of feed  108  (see, e.g., terminals  100 A and  100 B of  FIG. 5  or other suitable antenna ground feed structures). 
     Terminals  98  and  100  may be coupled respectively to antenna resonating element arm  104  and ground  102  (see, e.g.,  FIG. 2 ) using metal traces in the printed circuit from which antenna  40  is formed (e.g., vias in substrate  130  such as via  132 , metal traces on one or more dielectric layers in printed circuit substrate  130 , etc.). A return path such as return path  106  of  FIG. 2  may be formed using one or more vias in printed circuit substrate  130  such as illustrative return path vias  106 A and  106 B of  FIG. 5 . 
     A cross-sectional side view of antenna  40  of  FIG. 5  taken along line  134  and viewed in direction  136  is shown in  FIG. 6 . As shown in  FIG. 6 , antenna  40  may have a lower metal trace layer such as lower metal layer  102  that serves as antenna ground for antenna  40 . Antenna  40  may also have a metal trace such as upper metal trace  104  on the opposing surface of printed circuit substrate  130  (i.e., on the upper surface of printed circuit substrate  130 ). Metal trace  104  may serve as antenna resonating element arm  104  of antenna resonating element  100  of  FIG. 2 . If desired, arm  104  may have multiple branches, may have bent portions, may include embedded capacitors, inductors, switches, or other components, may be formed in one or more layers of printed circuit  130 , or may have other configurations. The illustrative configuration of  FIG. 6  in which arm  104  is formed from a strip of metal on one surface of substrate  130  that runs parallel a strip of metal that forms ground  102  on an opposing surface of substrate  130  is merely illustrative. 
     As shown in  FIG. 6 , antenna feed terminal  98  may be coupled to arm  104  by a via such as via  132 . Vias may also be used in forming return path  106  ( FIG. 2 ), as shown by return path via  106 A of  FIG. 6 . Vias such as illustrative return path via  106 A of  FIG. 6  may be shorted between the metal traces that form resonating element arm  104  and the traces that form antenna ground  102 . The traces on the lower surface of printed circuit substrate  130  may be adjacent to conductive structures in region  124  (e.g., battery  26 , etc.). The traces on the upper surface of printed circuit substrate  130  may be adjacent to inner surface  140  of housing  12  and may therefore be interposed between the wall of housing stalk portion  12 T and substrate  130 . In this configuration, housing  12  may have walls formed from a dielectric material such as plastic. During operation of antenna  40 , antenna signals may be transmitted through the plastic wall of housing  12  and may be received through the plastic housing wall. 
     The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20160112
Publication Date: 20180109
Grant Date: 20180109
Priority Date: 20160112
Inventors: McAuliffe Erin A.
DI NALLO CARLO
HUANG HUAN-CHU
Barrera Joel D.
PASCOLINI MATTIA
GUTERMAN JERZY S.
CHAWAN ARUN
COUSINS BENJAMIN
Panecki Lee M.
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q1/273", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1066", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1016", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1066", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/273", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/42", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/273", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/1016", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 57759415