PATENT DOCUMENT

Publication Number: US-10950932-B1
Application Number: US-201916584159-A
Country: US
Kind Code: B1

Title: Electronic device wide band antennas

Abstract:
An electronic device may have a housing with metal sidewalls. One of the metal sidewalls may have an opening. The electronic device may have a speaker module that has a speaker housing member. Conductive structures on the speaker housing member may have an opening that forms a slot element. The opening of the metal sidewall may be aligned with slot element. The slot element and an interior cavity of the speaker housing member may form a cavity-backed slot antenna. An antenna feed structure may be disposed at the opening of the speaker housing member. An antenna feed may be directly coupled to the antenna feed structure. The antenna feed structure may indirectly feed the slot antenna resonating element by capacitive coupling. A sealing member may be disposed at the opening of the metal sidewall.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a speaker box having an interior surface that defines a cavity and having conductive structures formed on an exterior surface of the speaker box, the conductive structures having an opening that serves as an open end for the cavity; and 
 an antenna that comprises:
 a slot antenna radiating element formed from the opening, the opening being partially defined by first and second opposing edges of the conductive structures; and 
 an antenna feed structure that is configured to indirectly feed the slot antenna radiating element and that has third and fourth opposing edges, the third edge being capacitively coupled to the first edge and the fourth edge being capacitively coupled to the second edge. 
 
 
     
     
       2. The electronic device defined in  claim 1 , wherein the third edge of the antenna feed structure is configured to induce an antenna current at the first edge of the conductive structures and the fourth edge of the antenna feed structure is configured to induce an antenna current at the second edge of the conductive structures. 
     
     
       3. The electronic device defined in  claim 2 , wherein the antenna further comprises an antenna feed having a positive antenna feed terminal coupled to the antenna feed structure and a ground antenna feed terminal coupled to the first edge of the conductive structures. 
     
     
       4. The electronic device defined in  claim 3 , wherein the opening is elongated along a dimension, the antenna feed structure is elongated along the dimension, and the first, second, third, and fourth edges extend along the dimension. 
     
     
       5. The electronic device defined in  claim 3 , wherein the antenna feed structure is disposed in the opening and the antenna feed is coupled across a gap between the first edge of the conductive structures and the third edge of the antenna feed structure. 
     
     
       6. The electronic device defined in  claim 1 , wherein the conductive structures surround the cavity and are coupled to a grounding structure, the slot antenna radiating element is backed by the cavity, and the antenna comprises a cavity-backed indirectly-fed slot antenna. 
     
     
       7. The electronic device defined in  claim 6 , further comprising:
 transceiver circuitry coupled to the antenna feed structure using a transmission line structure and configured to operate the cavity-backed indirectly-fed slot antenna in an ultra-wideband communications band comprising a frequency between 5 GHz and 8.5 GHz. 
 
     
     
       8. An electronic device, comprising:
 a peripheral housing structure having an aperture; 
 an electronic component module that includes a module housing member with a conductive surface, the conductive surface having an opening aligned with the aperture; 
 a slot antenna radiating element for an antenna, the slot antenna radiating element being formed from the opening; 
 an antenna element disposed in the opening and configured to indirectly feed the slot antenna radiating element; and 
 a liquid barrier interposed between the aperture and the opening. 
 
     
     
       9. The electronic device defined in  claim 8 , wherein the module housing member has a cavity defined by an interior surface of the module housing member and the cavity has an open end at the opening. 
     
     
       10. The electronic device defined in  claim 9 , wherein the electronic component module comprises a speaker system having speaker components in the cavity, the speaker components being coupled to the interior surface of the module housing member. 
     
     
       11. The electronic device defined in  claim 10 , wherein the antenna has an antenna feed that is directly coupled to the antenna element and the antenna element is configured to induce current to flow around a perimeter of the opening that forms the slot antenna radiating element. 
     
     
       12. The electronic device defined in  claim 10 , wherein the module housing member has first and second opposing walls, and additional walls that connect the first wall to the second wall, the conductive surface comprising an exterior surface of the first wall and respective exterior surfaces of the additional walls, and the second wall has a dielectric exterior surface. 
     
     
       13. The electronic device defined in  claim 8 , wherein the liquid barrier is aligned with the aperture and the opening and serves as a water seal configured to prevent water from entering an interior of the electronic device. 
     
     
       14. The electronic device defined in  claim 13 , wherein the module housing member is mounted to the peripheral housing structure using an attachment structure and is held in place using a retaining member. 
     
     
       15. The electronic device defined in  claim 14 , wherein the attachment structure is conductive and electrically connects the module housing member to the peripheral housing structure. 
     
     
       16. A wristwatch device, comprising:
 conductive peripheral sidewalls defining an interior and an exterior of the wristwatch device, wherein a given conductive peripheral sidewall of the conductive peripheral sidewalls has an elongated slot; 
 a component housing member at the interior and having a cavity that extends to an elongated opening in the component housing member, the elongated opening coupling the cavity to the exterior through the elongated slot; 
 a slot antenna radiating element formed from the opening in the component housing member; and 
 an antenna feed structure aligned with the elongated opening and configured to indirectly feed the slot antenna radiating element. 
 
     
     
       17. The wristwatch device defined in  claim 16 , wherein the cavity is surrounded by conductive structures of the component housing member, an elongated opening in the conductive structures forms the elongated opening in the component housing member, and the antenna feed structure is indirectly coupled to the conductive structures across a gap. 
     
     
       18. The wristwatch device defined in  claim 17 , further comprising:
 a display cover glass attached to the conductive peripheral sidewalls; 
 display circuitry mounted to the display cover glass; 
 a dielectric rear housing wall attached to the conductive peripheral sidewalls; and 
 antenna circuitry coupled to the dielectric rear housing wall, wherein the slot antenna radiating element, the antenna feed structure, and the cavity form a cavity-backed indirectly-fed slot antenna that is isolated from the display circuitry and the antenna circuitry. 
 
     
     
       19. The wristwatch device defined in  claim 16 , wherein the conductive peripheral sidewalls include an additional sidewall that opposes the given conductive peripheral sidewall, the additional sidewall being configured to receive a button member. 
     
     
       20. The wristwatch device defined in  claim 16 , wherein the conductive peripheral sidewalls include first and second additional sidewalls configured to receive a wrist strap, and the given conductive peripheral sidewall connects the first additional sidewall to the second additional sidewall.

Description:
BACKGROUND 
     This relates to electronic devices and, more particularly, to electronic devices with wireless communications circuitry. 
     Electronic devices are often provided with wireless communications capabilities. To satisfy consumer demand for small form factor wireless devices, manufacturers are continually striving to implement wireless communications circuitry such as antenna components using compact structures. At the same time, there is a desire for wireless devices to cover a growing number of communications bands. 
     Because antennas have the potential to interfere with each other and with components in a wireless device, care must be taken when incorporating antennas into an electronic device. Moreover, care must be taken to ensure that the antennas and wireless circuitry in a device are able to exhibit satisfactory performance over a range of operating frequencies. 
     It would therefore be desirable to be able to provide improved wireless communications circuitry for wireless electronic devices. 
     SUMMARY 
     An electronic device such as a wristwatch device may have a housing with metal portions such as metal sidewalls. A metal sidewall may have an elongated slot. The electronic device may include an electronic component module such as a speaker module having a (speaker) module housing member with (speaker) module housing walls. One or more speaker housing walls may have conductive structures formed on respective external surfaces of the speaker housing walls. The conductive structures may have an elongated opening that is aligned with the elongated slot in the metal sidewall. The speaker housing member may have a cavity defined by an interior surface of the speaker housing member and extending to an open end at the opening. The conductive structure may surround the cavity. The conductive structure may be grounded to the metal sidewall. The opening in the conductive structures may form a slot antenna resonating element for an antenna. An antenna feed structure may be disposed in the opening. The slot antenna resonating element may be backed by the cavity. The antenna formed from the slot antenna resonating element, the antenna feed structure, and the cavity, may be a cavity-backed indirectly-fed slot antenna. 
     The antenna may include an antenna feed having a positive antenna feed terminal coupled to the antenna feed structure and a ground antenna feed terminal coupled to the conductive structures. Transceiver circuitry may be coupled to antenna feed using a transmission line structure and may be configured to operate the antenna in an ultra-wideband communications (frequency) band between a frequency of 5 GHz and a frequency of 8.5 GHz. The antenna feed structure may directly receive antenna signals and may be configured to induce current to flow around a perimeter of the opening in the conductive structures. The antenna feed structure may have first and second opposing edges that are respectively coupled indirectly (capacitively) to first and second opposing edges of the opening in the conductive structure. 
     The electronic device may include a liquid barrier interposed between and aligned with the elongated slot in the metal sidewall and the elongated opening in the conductive structures. The liquid barrier may serve as a water seal (sealant) configured to prevent water from entering an interior of the electronic device. The speaker housing member may be mounted to the metal sidewall using an attachment structure such as conductive tape and may be held in place using a retaining member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front perspective view of an illustrative electronic device with wireless circuitry in accordance with some embodiments. 
         FIG. 2  is a schematic diagram of an illustrative electronic device with wireless circuitry in accordance with some embodiments. 
         FIG. 3  is a diagram of illustrative wireless circuitry in an electronic device in accordance with some embodiments. 
         FIG. 4  is a schematic diagram of an illustrative slot antenna in accordance with some embodiments. 
         FIG. 5  is a schematic diagram of an illustrative indirectly-fed slot antenna in accordance with some embodiments. 
         FIG. 6  is a front perspective view of an illustrative electronic component module having conductive walls and a cavity that are used to form an antenna in accordance with some embodiments. 
         FIG. 7  is a cross-sectional side view of an illustrative electronic device having an antenna of the type shown in  FIG. 6  in accordance with some embodiments. 
         FIG. 8  is a graph of antenna performance (antenna efficiency) for illustrative antenna structures of the types shown in  FIGS. 5-7  in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     An electronic device such as electronic device  10  of  FIG. 1  may be provided with wireless circuitry. The wireless circuitry may be used to support wireless communications in multiple wireless communications (frequency) bands. The wireless circuitry may include antennas. Antennas may be formed from electronic components such as displays, touch sensors, near-field communications antennas, wireless power coils, peripheral antenna resonating elements, conductive traces, and device housing structures, electronic component modules, as examples. 
     Electronic device  10  may be a computing device such as a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wristwatch device, a pendant device, a headphone or earpiece device, a device embedded in eyeglasses or other equipment worn on a user&#39;s head, or other wearable or miniature device, a television, a computer display that does not contain an embedded computer, a gaming device, a navigation device, an embedded system such as a system in which electronic equipment with a display is mounted in a kiosk or automobile, equipment that implements the functionality of two or more of these devices, or other electronic equipment. In the illustrative configuration of  FIG. 1 , device  10  is a portable device such as a wristwatch (e.g., a smart watch). Other configurations may be used for device  10  if desired. The example of  FIG. 1  is merely illustrative. 
     In the example of  FIG. 1 , device  10  includes a display such as display  14 . Display  14  may be mounted in a housing such as housing  12 . Housing  12 , which may sometimes be referred to as an enclosure or case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of any two or more of these materials. Housing  12  may be formed using a unibody configuration in which some or all of housing  12  is machined or molded as a single structure or may be formed using multiple structures (e.g., an internal frame structure, one or more structures that form exterior housing surfaces, etc.). Housing  12  may have metal sidewalls such as sidewalls  12 W or sidewalls formed from other materials. Examples of metal materials that may be used for forming sidewalls  12 W include stainless steel, aluminum, silver, gold, metal alloys, or any other desired conductive material. Sidewalls  12 W may sometimes be referred to herein as conductive sidewalls  12 W or conductive housing sidewalls  12 W. 
     Display  14  may be formed at (e.g., mounted on) the front side (face) of device  10 . Housing  12  may have a rear housing wall on the rear side (face) of device  10  such as rear housing wall  12 R that opposes the front face of device  10 . Conductive sidewalls  12 W may surround the periphery of device  10  (e.g., conductive sidewalls  12 W may extend around peripheral edges of device  10 ). Rear housing wall  12 R may be formed from conductive materials and/or dielectric materials. Examples of dielectric materials that may be used for forming rear housing wall  12 R include plastic, glass, sapphire, ceramic, wood, polymer, combinations of these materials, or any other desired dielectrics. 
     Rear housing wall  12 R and/or display  14  may extend across some or all of the length (e.g., parallel to the X-axis of  FIG. 1 ) and width (e.g., parallel to the Y-axis) of device  10 . Conductive sidewalls  12 W may extend across some or all of the height of device  10  (e.g., parallel to Z-axis). Conductive sidewalls  12 W and/or the rear housing wall  12 R may form one or more exterior surfaces of device  10  (e.g., surfaces that are visible to a user of device  10 ) and/or may be implemented using internal structures that do not form exterior surfaces of device  10  (e.g., conductive or dielectric housing structures that are not visible to a user of device  10  such as conductive structures that are covered with lavers such as thin cosmetic layers, protective coatings, and/or other coating layers that may include dielectric materials such as glass, ceramic, plastic, or other structures that form the exterior surfaces of device  10  and/or serve to hide housing walls  12 R and/or  12 W from view of the user). 
     Display  14  may be a touch screen display that incorporates a layer of conductive capacitive touch sensor electrodes or other touch sensor components (e.g., resistive touch sensor components, acoustic touch sensor components, force-based touch sensor components, light-based touch sensor components, etc.) or may be a display that is not touch-sensitive. Capacitive touch screen electrodes may be formed from an array of indium tin oxide pads or other transparent conductive structures. 
     Display  14  may include an array of display pixels formed from liquid crystal display (LCD) components, an array of electrophoretic display pixels, an array of plasma display pixels, an array of organic light-emitting diode display pixels, an array of electrowetting display pixels, or display pixels based on other display technologies. 
     Display  14  may be protected using a display cover layer. The display cover layer may be formed from a transparent material such as glass, plastic, sapphire or other crystalline dielectric materials, ceramic, or other clear materials. The display cover layer may extend across substantially all of the length and width of device  10 , for example. 
     Device  10  may include buttons such as button  18 . There may be any suitable number of buttons in device  10  (e.g., a single button, more than one button, two or more buttons, five or more buttons, etc.). Buttons may be located in openings in housing  12  (e.g., openings in conductive sidewall  12 W or rear housing wall  12 R) or in an opening in display  14  (as examples). Buttons may be rotary buttons, sliding buttons, buttons that are actuated by pressing on a movable button member, etc. Button members for buttons such as button  18  may be formed from metal, glass, plastic, or other materials. Button  18  may sometimes be referred to as a crown in scenarios where device  10  is a wristwatch device. 
     Housing  12  may include additional openings, such as opening  24 . Opening  24  may sometimes be referred to as a slot, cavity, hole, aperture, or port. Opening  24  may be a single continuous and elongated opening formed on a corresponding conductive sidewall  12 W. As shown in  FIG. 1 , opening  24  may be formed along the sidewall  12 W opposite to the sidewall  12 W at which button  18  is disposed. In other words, button  18  and opening  24  may be located on opposing sides of device  10 . 
     This configuration for opening  24  is merely illustrative. If desired, opening  24  may be formed in any portion of housing  12 . As examples, opening  24  may be formed in rear housing wall  12 R, in the same sidewall  12 W as button  18 , in any other sidewall  12 W, etc. 
     In some configurations, opening  24  may serve as an audio port or speaker port (e.g., a speaker opening or a speaker hole) through which audio signals generated from speaker components within device  10  pass to the exterior of device  10 . In such configurations, opening  24  may be aligned with a speaker box or a speaker cavity at the interior of device  10 . As an example, the speaker box may include a speaker driver and/or other speaker components for producing sound that passes through opening  24 . 
     Configurations in which opening  24  serves as an audio or speaker port are merely illustrative. If desired, opening  24  may serve as an opening for other purposes (e.g., for cosmetic purposes, for sensor purposes, for attachment purposes, etc.). Additionally, opening  24  may have any desired shape: a rectangular shape, an elliptical shape, shapes with curved edges, shapes with straight edges, shapes with curved and straight edges, etc. If desired, opening  24  may be filed with a dielectric material such as rubber, plastic, ceramic, polymer, glass, sapphire, fabric, mesh materials, air, or other dielectrics. 
     Device  10  may, if desired, be coupled to a strap such as strap  16 . Strap  16  may be used to hold device  10  against a user&#39;s wrist (as an example). Strap  16  may sometimes be referred to herein as wrist strap  16 . In the example of  FIG. 1 , wrist strap  16  is connected to opposing sides  8  of device  10 . Conductive sidewalls  12 W on sides  8  of device  10  may include attachment structures for securing wrist strap  16  to housing  12  (e.g., lugs or other attachment mechanisms that configure housing  12  to receive wrist strap  16 ). Configurations that do not include straps may also be used for device  10 . 
     A schematic diagram showing illustrative components that may be used in device  10  is shown in  FIG. 2 . As shown in  FIG. 2 , device  10  may include control circuitry  28 . Control circuitry  28  may include storage such as storage circuitry. The storage circuitry may include hard disk drive storage, 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. 
     Control circuitry  28  may also include processing circuitry. The processing circuitry may be used to control the operation of device  10 . The processing circuitry may include one or more microprocessors, microcontrollers, digital signal processors, host processors, baseband processor integrated circuits, application specific integrated circuits, central processing units (CPUs), etc. Control circuitry  28  may be configured to perform operations in device  10  using hardware (e.g., dedicated hardware or circuitry), firmware, and/or software. Software code for performing operations in device  10  may be stored on the storage circuitry of control circuitry  28  (e.g., the storage circuitry may include non-transitory (tangible) computer readable storage media that stores the software code). The software code may sometimes be referred to as program instructions, software, data, instructions, or code. Software code stored on the storage circuitry of control circuitry  28  may be executed by the processing circuitry of control circuitry  28 . 
     Control circuitry  28  may be used to run software on device  10  such as external node location applications, satellite navigation applications, internet browsing applications, voice-over-internet-protocol (VOIP) telephone call applications, email applications, media playback applications, operating system functions, etc. To support interactions with external equipment, control circuitry  28  may be used in implementing communications protocols. Communications protocols that may be implemented using control circuitry  28  include internet protocols, wireless local area network protocols (e.g., IEEE 802.11 protocols—sometimes referred to as Wi-Fi®), protocols for other short-range wireless communications links such as the Bluetooth® protocol or other wireless personal area network (WPAN) protocols, IEEE 802.11ad protocols, cellular telephone protocols, MIMO protocols, antenna diversity protocols, satellite navigation system protocols (e.g., global positioning system (GPS) protocols, global navigation satellite system (GLONASS) protocols, etc.), IEEE 802.15.4 ultra-wideband communications protocols or other ultra-wideband communications protocols, etc. Each communications protocol may be associated with a corresponding radio access technology (RAT) that specifies the physical connection methodology used in implementing the protocol. 
     Input-output circuitry  44  may include input-output devices  32 . Input-output devices  32  may be used to allow data to be supplied to device  10  and to allow data to be provided from device  10  to external devices. Input-output devices  32  may include user interface devices, data port devices, and other input-output components. For example, input-output devices  32  may include touch screens, displays without touch sensor capabilities, buttons, scrolling wheels, touch pads, key pads, keyboards, microphones, cameras, buttons, speakers, status indicators, light sources, audio jacks and other audio port components, vibrators or other haptic feedback engines, digital data port devices, light sensors (e.g., infrared light sensors, visible light sensors, etc.), light-emitting diodes, motion sensors (accelerometers), capacitance sensors, proximity sensors, magnetic sensors, force sensors (e.g., force sensors coupled to a display to detect pressure applied to the display), etc. 
     Input-output circuitry  44  may include wireless circuitry  34  (sometimes referred to herein as wireless communications circuitry  34 ). Wireless circuitry  34  may include coil  50  and wireless power receiver  48  for receiving wirelessly transmitted power from a wireless power adapter. Wireless power receiver  48  may include, for example, rectifier circuitry and other circuitry for powering or charging a battery on device  10  using wireless power received by coil  50 . Coil  50  may, as an example, receive wireless power through rear housing wall  12 R ( FIG. 1 ) when mounted to a wireless power adapter. To support wireless communications, wireless circuitry  34  may include radio-frequency (RF) transceiver circuitry formed from one or more integrated circuits, power amplifier circuitry, low-noise input amplifiers, passive RF components, one or more antennas such as antennas  40 , transmission lines, and other circuitry for handling RF wireless signals. Wireless signals may also be sent using light (e.g., using infrared communications). 
     Wireless circuitry  34  may include radio-frequency transceiver circuitry  52  for handling various radio-frequency communications bands. For example, radio-frequency transceiver circuitry  52  may include Bluetooth® and WiFi® transceiver circuitry  36 , cellular telephone transceiver circuitry  38 , Global Positioning System (GPS) receiver circuitry  42 , near-field communications circuitry  46 , and ultra-wideband (UWB) transceiver circuitry  54 . Bluetooth® and WiFi® Transceiver circuitry  36  may be wireless local area network (WLAN) and/or wireless personal area network (WPAN) transceiver circuitry. Bluetooth® and WiFi® Transceiver circuitry  36  may handle 2.4 GHz and 5 GHz bands for WiFi® (IEEE 802.11) communications or other WLAN bands and may handle the 2.4 GHz Bluetooth® communications band or other WPAN bands. Transceiver circuitry  36  may sometimes be referred to herein as WLAN transceiver circuitry  36 . 
     Wireless circuitry  34  may use cellular telephone transceiver circuitry  38  (sometimes referred to herein as cellular transceiver circuitry  38 ) for handling wireless communications in frequency ranges (communications bands) such as a low band (sometimes referred to herein as a cellular low band LB) from 600 to 960 MHz, a midband (sometimes referred to herein as a cellular midband MB) from 1400 or 1700 MHz to 2170 or 2200 MHz, and a high band (sometimes referred to herein as a cellular high band HB) from 2200 or 2300 MHz to 2700 MHz (e.g., a high band with a peak at 2400 MHz) or other communications bands between 600 MHz and 4000 MHz or other suitable frequencies (as examples). Cellular transceiver circuitry  38  may handle voice data and non-voice data. 
     Wireless circuitry  34  may include satellite navigation system circuitry such as Global Positioning System (GPS) receiver circuitry  42  for receiving GPS signals at 1575 MHz or for handling other satellite positioning data (e.g., GLONASS signals at 1609 MHz). Satellite navigation system signals for receiver  42  are received from a constellation of satellites orbiting the earth. 
     Wireless circuitry  34  may include ultra-wideband (UWB) transceiver circuitry  54  that supports communications using the IEEE 802.15.4 protocol and/or other wireless communications protocols (e.g., ultra-wideband communications protocols). Ultra-wideband wireless signals may be based on an impulse radio signaling scheme that uses band-limited data pulses. Ultra-wideband signals may have any desired bandwidths such as bandwidths between 499 MHz and 1331 MHz, bandwidths greater than 500 MHz, etc. The presence of lower frequencies in the baseband may sometimes allow ultra-wideband signals to penetrate through objects such as walls. In an IEEE 802.15.4 system, a pair of electronic devices may exchange wireless time stamped messages. Time stamps in the messages may be analyzed to determine the time of flight of the messages and thereby determine the distance (range) between the devices and/or an angle between the devices (e.g., an angle of arrival of incoming radio-frequency signals). Transceiver circuitry  54  may operate (i.e., convey radio-frequency signals) in frequency bands such as an ultra-wideband frequency band (i.e., an ultra-wideband communications band) between about 5 GHz and about 8.5 GHz (e.g., a 6.5 GHz frequency band, an 8 GHz frequency band, and/or at other suitable frequencies). 
     Wireless circuitry  34  can include circuitry for other short-range and long-range wireless links if desired. For example, wireless circuitry  34  may include circuitry for receiving television and radio signals, paging system transceivers, near field communications (NFC) transceiver circuitry  46  (e.g., an NFC transceiver operating at 13.56 MHz or another suitable frequency), etc. 
     In NFC links, wireless signals are typically conveyed over a few inches at most. In satellite navigation system links, cellular telephone links, and other long-range links, wireless signals are typically used to convey data over thousands of feet or miles. In WLAN and WPAN links at 2.4 and 5 GHz and other short-range wireless links, wireless signals are typically used to convey data over tens or hundreds of feet. Antenna diversity schemes may be used if desired to ensure that the antennas that have become blocked or that are otherwise degraded due to the operating environment of device  10  can be switched out of use and higher-performing antennas used in their place. 
     Wireless circuitry  34  may include antennas  40 . Antennas  40  may be formed using any suitable antenna types. For example, antennas  40  may include antennas with resonating elements that are formed from slot antenna structures, loop antenna structures, patch antenna structures, stacked patch antenna structures, antenna structures having parasitic elements, inverted-F antenna structures, planar inverted-F antenna structures, helical antenna structures, monopole antennas, dipole antenna structures, Yagi (Yagi-Uda) antenna structures, surface integrated waveguide structures, hybrids of these designs, etc. If desired, one or more of antennas  40  may be cavity-backed antennas. 
     Different types of antennas may be used for different bands and combinations of bands. For example, one type of antenna may be used in forming a local wireless link antenna whereas another type of antenna is used in forming a remote wireless link antenna. If desired, space may be conserved within device  10  by using a single antenna to handle two or more different communications bands. For example, a single antenna  40  in device  10  may be used to handle communications in a WiFi® or Bluetooth® communication band at 2.4 GHz, a GPS communications band at 1575 MHz, a WiFi® communications band at 5.0 GHz, one or more cellular telephone communications bands such as a cellular midband between about 1700 MHz and 2200 MHz and a cellular high band between about 2200 and 2700 MHz, and UWB communications band between about 5 GHz and 8.3 GHz. If desired, a combination of antennas for covering multiple frequency bands and dedicated antennas for covering a single frequency band may be used. 
     It may be desirable to implement at least some of the antennas in device  10  using portions of electronic components that would otherwise not be used as antennas and that support additional device functions. As an example, it may be desirable to induce antenna currents in components such as display  14  ( FIG. 1 ), so that display  14  and/or other electronic components (e.g., a touch sensor, near-field communications loop antenna, conductive display assembly or housing, conductive shielding structures, etc.) can serve as part of an antenna for Wi-Fi, Bluetooth, GPS, cellular frequencies, UWB, and/or other frequencies without the need to incorporate separate bulky antenna structures in device  10 . 
       FIG. 3  is a diagram showing how transceiver circuitry  52  in wireless circuitry  34  may be coupled to antenna structures of a corresponding antenna  40  using signal paths such as radio-frequency transmission line  60 . Wireless circuitry  34  may be coupled to control circuitry  28  over data and control path  56 . Control circuitry  28  may be coupled to input-output devices  32 . Input-output devices  32  may supply output from device  10  and may receive input from sources that are external to device  10 . 
     To provide antenna  40  with the ability to cover communications bands (frequencies) of interest, antenna  40  may be provided with circuitry such as filter circuitry (e.g., one or more passive filters and/or one or more tunable filter circuits). Discrete components such as capacitors, inductors, and resistors may be incorporated into the filter circuitry. Capacitive structures, inductive structures, and resistive structures may also be formed from patterned metal structures (e.g., part of an antenna). If desired, antenna  40  may be provided with adjustable circuits such as tunable components  58  to tune the antenna over communications bands of interest. Tunable components  58  may include tunable inductors, tunable capacitors, or other tunable components. Tunable components such as these may be based on switches and networks of fixed components, distributed metal structures that produce associated distributed capacitances and inductances, variable solid-state devices for producing variable capacitance and inductance values, tunable filters, or other suitable tunable structures. 
     During operation of device  10 , control circuitry  28  may issue control signals on one or more paths such as path  64  that adjust inductance values, capacitance values, or other parameters associated with tunable components  58 , thereby tuning antenna  40  to cover desired communications bands. 
     Radio-frequency transmission line  60  may include a positive signal line such as signal conductor  66  and a ground signal line such as ground conductor  68 . Radio-frequency transmission line  60  may include a coaxial cable, stripline transmission line, microstrip transmission line, edge-coupled microstrip transmission line, edge-coupled stripline transmission line, waveguide structure, combinations of these, etc. 
     Transmission lines in device  10  such as radio-frequency transmission line  60  may be integrated into rigid and/or flexible printed circuit boards if desired. In one suitable arrangement, transmission lines such as radio-frequency transmission line  60  may also include transmission line conductors (e.g., signal conductor  66  and ground conductor  68 ) integrated within multilayer laminated structures (e.g., layers of a conductive material such as copper and a dielectric material such as a resin that are laminated together without intervening adhesive). The multilayer laminated structures may, if desired, be folded or bent in multiple dimensions (e.g., two or three dimensions) and may maintain a bent or folded shape after bending (e.g., the multilayer laminated structures may be folded into a particular three-dimensional shape to route around other device components and may be rigid enough to hold its shape after folding without being held in place by stiffeners or other structures). All of the multiple layers of the laminated structures may be batch laminated together (e.g., in a single pressing process) without adhesive (e.g., as opposed to performing multiple pressing processes to laminate multiple layers together with adhesive). 
     A matching network formed from components such as inductors, resistors, and capacitors may be used in matching the impedance of antenna  40  to the impedance of radio-frequency transmission line  60 . Matching network components may be provided as discrete components (e.g., surface mount technology components) or may be formed from housing structures, printed circuit board structures, traces on plastic supports, etc. Matching network components may, for example, be interposed on radio-frequency transmission line  60 . The matching network components may be adjusted using control signals received from control circuitry  28  if desired. Components such as these may also be used in forming filter circuitry in antenna  40  (e.g., tunable components  58 ). 
     Radio-frequency transmission line  60  may be directly connected to an antenna resonating element and antenna ground for antenna  40  or may be coupled to antenna feed structures that are used in indirectly feeding an antenna resonating element for antenna  40 . As an example, antenna  40  may be a slot antenna, an inverted-F antenna, a loop antenna, a patch antenna, or other antenna having an antenna feed  62  with a positive antenna feed terminal such as positive antenna feed terminal  70  and a ground antenna feed terminal such as ground antenna feed terminal  72 . Signal conductor  66  may be coupled to positive antenna feed terminal  70  and ground conductor  68  may be coupled to ground antenna feed terminal  72 . 
     If desired, antenna  40  may include an antenna resonating element that is indirectly fed using near-field coupling. In an indirect feeding arrangement, radio-frequency transmission line  60  may be coupled to an antenna feed structure that indirectly feeds antenna structures such as an antenna resonating element via near-field electromagnetic coupling. This example is merely illustrative and, in general, any desired antenna feeding arrangement may be used. 
     Antenna  40  may be formed using any desired antenna structures. In one suitable arrangement, antenna  40  may be formed using a slot antenna structure. An illustrative slot antenna structure that may be used for forming antenna  40  is shown in  FIG. 4 . As shown in  FIG. 4 , antenna  40  may include a conductive structure such as conductor  82  that has been provided with a dielectric opening such as dielectric opening  74 . Opening  74  may sometimes be referred to herein as slot  74 , slot antenna resonating element  74 , slot element  74 , or slot radiating element  74 . In the configuration of  FIG. 4 , slot element  74  is a closed slot, because portions of conductor  82  completely surround and enclose slot element  74 . 
     Antenna feed  62  for antenna  40  may be formed using positive antenna feed terminal  70  and ground antenna feed terminal  72 . In general, the frequency response of an antenna is related to the sizes and shapes of the conductive structures in the antenna. Slot antennas of the type shown in  FIG. 4  tend to exhibit response peaks when slot perimeter P is equal to the effective wavelength of operation of antenna  40  (e.g. where perimeter P is equal to two times length L plus two times width W). The effective wavelength of operation may be equal to a freespace wavelength multiplied by a constant value that is determined by the dielectric materials in and surrounding slot element  74 . Antenna currents may flow between antenna feed terminals  70  and  72  around perimeter P of slot element  74 . In the example where slot length L is much greater than slot width W, the length of antenna  40  will tend to be about half of the length of other types of antennas such as inverted-F antennas configured to handle signals at the same frequency. Given equal antenna volumes, antenna  40  may therefore be able to handle signals at approximately twice the frequency of other antennas such as inverted-F antennas, for example. 
     Antenna feed  62  may be coupled across slot element  74  at a location between opposing edges  76  and  78  of slot element  74 . For example, antenna feed  62  may be located at a distance  80  from edge  76  of slot element  74 . Distance  80  may be adjusted to match the impedance of antenna  40  to the impedance of radio-frequency transmission line  60  ( FIG. 3 ). For example, the antenna current flowing around slot element  74  may experience an impedance of zero at edges  76  and  78  of slot element  74  (e.g., a short circuit impedance) and an infinite (open circuit) impedance at the center of slot element  74  (e.g., at a fundamental frequency of the slot). Antenna feed  62  may be located between the center of slot element  74  and edge  76  at a location where the antenna current experiences an impedance that matches the impedance of radio-frequency transmission line  60 , for example (e.g., distance  80  may be between 0 and ¼ of the effective wavelength of operation of antenna  40 ). 
     The example of  FIG. 4  is merely illustrative. In general, slot element  74  may have any desired shape (e.g., where the perimeter P of slot element  74  defines radiating characteristics of antenna  40 ). For example, slot element  74  may have a meandering shape with different segments extending in different directions, may have straight and/or curved edges, etc. Conductor  82  may be formed from any desired conductive electronic device structures. For example, conductor  82  may include conductive traces on printed circuit boards or other substrates, sheet metals, metal foils, conductive structures associated with display  14  ( FIG. 1 ), conductive portions of housing  12  (e.g., conductive sidewalls  12 W of  FIG. 1 ), or other conductive structures within device  10 . In one suitable arrangement, different sides (edges) of slot element  74  are defined by different conductive structures. For example, one side of slot element  74  may be formed from conductive sidewalls  12 W whereas the other side of slot element  74  is formed from conductive structures associated with display  14 . 
     In some applications, it may be desirable to improve the antenna performance of an electronic device to provide increased bandwidth and to cover additional frequencies of interest such as frequencies in an ultra-wideband communications band between about 5 GHz and about 8.5 GHz. To at least partly meet performance requirements and provide additional antenna frequency coverage especially in an ultra-wideband communications band, antenna  40  may be formed from a slot element that is indirectly fed by an antenna feed structure within the slot element. 
       FIG. 5  is a diagram showing how antenna  40  may be formed from a slot element that is indirectly fed by an antenna feed structure within the slot element. As shown in  FIG. 5 , antenna  40  may include an antenna feed structure such as antenna feed structure  90  (sometimes referred to as antenna feed element  90  or antenna element  90 ) disposed within slot element  74 . Antenna feed  62  may be coupled between antenna feed structure  90  and conductor  82  (e.g., positive antenna feed terminal  70  may be coupled to antenna feed structure  90  whereas ground antenna feed terminal  72  is coupled to conductor  82 ). Antenna feed structure  90  may be formed from a strip of conductive material (e.g., a conductive trace patterned on a dielectric substrate within slot element  74 ). 
     When antenna feed  62  is transmitting radio-frequency signals, corresponding antenna currents may flow along the perimeter of antenna feed structure  90 . These antenna currents may excite antenna current I to flow along the perimeter of slot element  74  via near-field electromagnetic (e.g., capacitive) coupling  96 . Antenna current I may produce wireless radio-frequency signals that are radiated by antenna  40  (e.g., antenna feed structure  90  may serve as an indirect feed element that excites antenna  40  to radiate radio-frequency signals). Similarly, when antenna  40  is receiving radio-frequency signals, the received radio-frequency signals may produce antenna currents I on slot element  74 . Antenna currents I may produce corresponding antenna currents on antenna feed structure  90  (e.g., via near-field electromagnetic coupling  96 ) that are received by antenna feed  62 . 
     As shown in  FIG. 5 , antenna feed structure  90  may be an elongated conductive element that extends along a longitudinal axis (e.g., the longest dimension) running parallel to the longitudinal axis of slot element  74 . For example, slot element  74  may have a length L 1  whereas antenna feed structure  90  has a smaller length L 2  that runs parallel to length L 1  of slot element  74 . In the illustrative example of  FIG. 5 , antenna feed structure  90  is disposed at the left side of slot element  74 . For example, the gap between the left edge of antenna feed structure  90  and the left edge of conductor  82  defining slot element  74  may be smaller than the gap between the right edge of antenna feed structure  90  and the right edge of conductor  82  defining slot element  74 . However, this is merely illustrative. If desired, antenna feed structure  90  may be disposed at the right side of slot element  74 , at the center of slot element  74 , or may disposed at any suitable location within slot element  74 . 
     The radio-frequency performance of antenna  40  may be tuned by adjusting the length and/or placement of antenna feed structure  90  within slot element  74 . As an example, by extending the length of antenna feed structure  90 , antenna  40  may exhibit a change in frequency response (e.g., an increase in antenna efficiency at some frequencies and a decrease in antenna efficiency at other frequencies) because of the change in capacitive coupling between antenna feed structure  90  and conductor  82 . As another example, by moving antenna feed structure  90  within slot element  74 , the feed location for slot antenna resonating element  74  may be changed. Changing the feed location for antenna feed  62  may adjust the impedance of antenna  40  (e.g., to have better impedance matching characteristics with a radio-frequency transmission line coupled to antenna feed  62 ). As such, the antenna performance of antenna  40  may be altered by adjusting the length and/or position of antenna feed structure  90  without requiring adjustment to the dimensions of slot element  74  and/or conductor  82 , which may be bound by more stringent device space constraints and other manufacturing constraints. 
     In the example of  FIG. 5 , antenna feed structure  90  is formed within the same plane as conductor  82  (e.g., the plane of the page for  FIG. 5 ). If desired, antenna feed structure  90  may be formed in a parallel plane that is different from the plane on which conductor  82  is formed. More generally, antenna feed structure  90  and conductor  82  may be configured in any desirable manner, such that one or more edges of antenna feed structure  90  are indirectly (near-field) coupled to one or more corresponding opposing edges of conductor  82 . 
     As an example, antenna feed structure  90  may be provided with opposing upper and lower edges that are respectively located equidistant from the upper and lower opposing edges of slot element  74  (e.g., where slot element  74  forms an upper gap between the upper edge of antenna feed structure  90  and the upper edge of slot element  74  and where slot element  74  forms a lower gap between the lower edge of antenna feed structure  90  and the lower edge of slot element  74 ). Antenna feed  62  is coupled across the upper gap, and the upper gap is the same size as the lower gap in the example of  FIG. 5 . This is merely illustrative. If desired, antenna feed  62  may be coupled across the lower gap and/or the lower gap may be larger or smaller than the upper gap. Antenna feed  62  may be coupled between the left edge of antenna feed structure  90  and the left edge of slot element  74 , if desired. 
       FIG. 6  shows a perspective view of an illustrative system  100  that may implement an indirectly-fed slot antenna of the type shown in  FIG. 5 . In particular, system  100  may be a speaker module, an electronic component module having a cavity, a cavity system used to house components, or any other suitable system implemented in device  10  ( FIG. 1 ). The illustrative example where system  100  is a speaker module is described herein as an example. As such, system  100  may be referred to herein as speaker system  100  or speaker module  100 . However, system  100  may be implemented as a non-speaker system and/or using other components or structures as desirable. 
     As an example, speaker module  100  may include a speaker housing member (e.g., a speaker box) such as speaker housing member  102 . In scenarios where system  100  is more generally an electronic component module, housing member  102  may generally be referred to as module housing member  102  or component housing member  102 . Speaker housing member  102  may have a cuboid shape with six sides (faces) formed from six rectangles placed at right angles with respect to each other. As shown in  FIG. 6 , for example, speaker housing member  102  may have front and back speaker housing walls  102 F and  102 R parallel to the X-Z plane. Speaker housing member  102  may have top and bottom speaker housing walls  102 T and  102 B parallel to the X-Y plane. Speaker housing member  102  may have two left and right speaker housing walls  102 S (sometimes referred as the two side speaker housing walls  102 S) parallel to the Y-Z plane. 
     Front speaker housing wall  102 F may have an opening  104  (sometimes referred to herein as slot  104 , aperture  104 , or slot element  104 ). Speaker housing member  102  may define an interior cavity such as cavity  106 . The six speaker housing walls may define cavity  106 , such that cavity  106  has edges defined by the speaker housing walls. As an example, cavity  106  may be fully enclosed at speaker housing walls  102 T,  102 B,  102 R, and  102 S (both left and right housing walls) and may only be partially enclosed at speaker housing wall  102 F. Cavity  106  may have an open end at opening  104 . In other words, speaker housing member  102  may have cavity  106  that connects to the exterior of speaker housing member  102  via an opening at speaker housing wall  102 F (e.g., opening  104 ). 
     Speaker housing member  102  may be formed from materials such as plastic, fiber-based composites, conductive materials (e.g., metal), other materials, or a combination of these materials. As an example, speaker housing member  102  may be formed from a hollow dielectric support structure such as a hollow box-shaped structure or any other structure surrounding cavity  106 . Conductive structures may be formed on one or more of the exterior surfaces of the hollow dielectric support structure to provide a conductive exterior to speaker housing member  102 . If desired, conductive structures may also be formed on one or more interior surfaces of the hollow dielectric support structure. The conductive structures of speaker housing member  102  may be electrically connected to one or more grounding structure such as one or more conductive portions of housing  12  ( FIG. 1 ). 
     In some configurations, the external surface of each speaker housing wall may be patterned with conductive material such as metal (e.g., metal traces). For example, front speaker housing wall  102 F, back speaker housing wall  102 B, top speaker housing wall  102 T, bottom speaker housing wall  102 B, and the two side speaker housing walls  102 S may each include dielectric walls (e.g., dielectric walls of a hollow dielectric support structure) that are covered with a layer of conductive material (e.g., that are patterned with conductive traces, covered with metal foil, etc.). If desired, conductive material may only cover some of each or a subset of these speaker housing walls. For example, the conductive material on front speaker housing wall  102 F may have an opening that aligns with opening  104 . If desired, all of the speaker housing walls except rear speaker housing wall  102 R may have a conductive layer at its exterior surface, such that rear wall  102  has a dielectric exterior surface. 
     The conductive structures on speaker module  100  may be used to implement an indirectly-fed slot antenna of the type shown in  FIG. 5 . For example, conductive material on front speaker housing wall  102 F may define the edges of opening  104 . Opening  104  may therefore form a slot element for antenna  40  (e.g., a slot antenna resonating element or a slot antenna radiating element for antenna  40  such as conductor  82  and slot element  74  of  FIG. 5 ). The conductive material on top speaker housing wall  102 T, front speaker housing wall  102 F, bottom speaker housing wall  102 B, the two side speaker housing walls  102 S, and optionally rear speaker housing wall  102 R may define conductive edges of cavity  106 , which thereby serves as an antenna cavity that backs antenna  40  (e.g., backs opening  104  forming a slot antenna resonating element for antenna  40 , sometimes referred to as slot element  104  or slot resonating element  104 ). More specifically, conductive structures on top speaker housing wall  102 T, bottom speaker housing wall  102 B, the two side speaker housing walls  102 S, and optionally  102 R may define a grounded cavity for slot antenna resonating element  104 . 
     Antenna  40  may therefore sometimes be referred to as a cavity-backed antenna, a cavity-backed slot antenna, or a cavity-backed indirectly-fed slot antenna. In scenarios where antenna  40  is formed as a cavity-backed antenna, antenna elements (e.g., slot element  74  and antenna feed structure  90 ) for antenna  40  may be isolated from their surrounding environment such as surrounding electronic components in electronic device  10  ( FIG. 1 ). This allows for more predictable and well-controlled antenna performance without interference from the surrounding environment. The cavity may also contribute to antenna bandwidth and/or radiation directionality for antenna  40 . 
     As shown in  FIG. 6 , antenna feed structure  90  may be disposed in slot element  104  at front speaker housing wall  102 F. Antenna feed structure  90  may have an upper edge that opposes an upper edge of slot element  104 , thereby defining a gap. Antenna feed  62  may be coupled across the gap. A first antenna feed terminal (e.g., positive antenna feed terminal  70 ) may be coupled to antenna feed structure  90  on one side of the gap. A second antenna feed terminal (e.g., ground antenna feed terminal  72 ) may be coupled to the conductive structure on front speaker housing wall  102 F on the opposing side of the gap. 
     A transmission line structure such transmission line  108  (e.g., a radio-frequency transmission line such as radio-frequency transmission line  60  of  FIG. 3 ) may be coupled to antenna feed  62 , thereby directly feeding antenna feed structure  90 . Transmission line  108  may be coupled to antenna feed  62  from within cavity  106  or from the exterior of speaker module  100 . Antenna feed structure  90  may be indirectly coupled (e.g., near-field-coupled or capacitively coupled) to the conductive structure on front speaker housing wall  102 F surrounding slot element  104 . 
     As an example, this indirect coupling may occur between the corresponding elongated edges of the antenna feed structure  90  and the parallel elongated edges of the conductive structure on front speaker housing wall  102 F surrounding slot element  104  (e.g., between opposing upper edges of antenna feed structure  90  and the conductive structure surrounding slot element  104 , between opposing lower edges of antenna feed structure  90  and the conductive structure surrounding slot element  104 ). Antenna feed structure  90  may thereby indirectly feed slot antenna resonating element  104  at front speaker housing wall  102 F (e.g., through a coupling similar to coupling  96  in  FIG. 5 ). 
     Front speaker housing wall  102 F, top speaker housing wall  102 T, and/or other walls of speaker housing member  102  may have depressions, indentations, or other recesses along their exterior surfaces to accommodate for transmission line  108  at the exterior surface of speaker housing member  102 . If desired, a transmission line may be coupled to antenna feed  62  in other manners such as a transmission line provided through holes in speaker housing member  102 , or in any suitable other manners. 
     In the example of system  100  being a speaker module, speaker components for the speaker module may be disposed within cavity  106 . As shown in  FIG. 6 , speaker components  110  such as speakers or speaker drivers may be mounted to one or more interior surfaces of one or more speaker housing walls (e.g., to an interior surface of bottom speaker housing wall  102 B). A speaker may have speaker drivers that have coils, magnets, and other electromagnetic structure that can move diaphragms in response to signals received over acoustic signal lines (e.g., through rear speaker housing wall  102 R). One or more of these components for the speaker may be provided within cavity  106 . Speaker components, when operated, may produce sound that is emitted through opening  104  at front wall  102 F. Opening  104  at front wall  102  may include a mesh structure or other acoustically transparent speaker port material through which the sound travels. 
     While  FIG. 6  shows a single piece of circuitry adjacent to the bottom, side, and back speaker housing walls, this is merely illustrative. If desired, other speaker components as well as non-speaker components (e.g., components in addition to or instead of components  110  in  FIG. 6 ) may also be disposed within cavity  106  and mounted to an interior surface of speaker housing member  102 . 
     By forming antenna  40  using one or more structures for other electronic device components such as speaker module  100 , antenna  40  may implemented in a space-efficient manner, which is especially desirable in a small compact device such as a wristwatch, where space for components is at a premium. Additionally, the dimensions of a speaker box in a small compact device such as a wristwatch, when used to implement antenna  40 , may be appropriately sized to offer frequency coverage at higher frequencies such as frequencies in an ultra-wideband communications band between about 5 GHz and about 8.5 GHz (e.g., a 6.5 GHz frequency band, an 8 GHz frequency band, and/or at other suitable frequencies). 
       FIG. 7  shows a cross-sectional view of electronic device  10  (taken across the central Y-Z plane of device  10  in  FIG. 1 ) that may be provided with a speaker module of the type shown in  FIG. 6 . As shown in  FIG. 7 , electronic device  10  may have device housing sidewall  12 W, device rear housing wall  12 R, and cover glass  120  (e.g., a display cover glass). As an illustrative example, sidewall  12 W may be formed from a conductive material, while rear housing wall  12 R and cover glass  120  may be formed from one or more dielectric materials (e.g., sapphire, ceramic, plastic, glass, zirconia, etc.). Cover glass  120  may be mounted to sidewall  12 W and may be secured to sidewall  12 W using latches, screws, adhesive, or other attachment structures. Similarly, rear housing wall  12 R may be attached to sidewall  12 W using any suitable attachment structures (e.g., latches, screws, adhesive, etc.). This configuration for sidewall  12 W, rear housing wall  12 R, and cover glass  120  is merely illustrative. In general, any desirable materials configured in any desirable manner may be used to implement the cover glass and housing structures of device  10 . 
     The housing sidewalls  12 W as shown in  FIG. 1  may include a four-sided peripheral conductive structure defining a rectangular perimeter. Two of the side (e.g., opposing sides  8  in  FIG. 1 ) may be configured to receive wrist straps (e.g., straps  16  in  FIG. 1 ). Referring to  FIG. 7 , the sidewall  12 W shown in  FIG. 7  may be a sidewall  12 W that joins (and is perpendicular to) the two sides of the sidewalls  12 W to which wrist straps may be configured to be attached. This configuration may be described herein as an example. However, if desired, device  10  may be configured to have wrist straps (and/or) buttons be coupled to the sidewall  12 W shown in  FIG. 7 . 
     As shown in  FIG. 7 , speaker module  100  may be coupled (e.g., attached or mounted) to sidewall  12 W. As an example, conductive adhesive  112  (e.g., conductive tape, conductive foam, a conductive gasket, etc.) may couple speaker housing wall  102 F of speaker housing member  102  to sidewall  12 W. As such, conductive adhesive  112  may mechanically attach speaker module  100  to sidewall  12 W. Conductive adhesive  112  may also electrically conductive structure on the wall of speaker housing member  102  (e.g., conductive structures on the exterior surface of front speaker housing wall  102 F, conductive structures on speaker housing member  102  that define slot element  104  and/or cavity  106 ) to sidewall  12 W (e.g., serving as an electrical ground or an antenna ground). The use of a conductive adhesive is merely illustrative. If desired, speaker housing member  102  be attached to sidewall  12 W using any other suitable conductive attachment structures such as screw-based attachment structures, latch-based attachment structures, clip-based attachment structures, combinations of these structures, etc. If desired, mechanical attachment members may be separate from electrical connection members when coupling sidewall  12 W to speaker housing member  102 . 
     Sidewall  12 W as shown in  FIG. 7  may include opening  24  (e.g., an opening elongated in the dimension of X). Speaker housing member  102  of speaker module  100  may have an opening at front speaker housing wall  102 F (e.g., opening  104 , the opening at which antenna feed structure  90  is disposed) that is aligned with opening  24 . Opening  104  may have a matching profile or outline to opening  24  (e.g., may have the same size and/or the same shape as opening  24 ). In the example of  FIG. 7 , antenna feed structure  90  is illustratively isolated from other structures and floating within opening  104 . This is merely illustrative. If desired, antenna feed structure  90  may be formed on a dielectric support structure disposed at opening  104 , may be coupled to a dielectric portion of speaker housing member  102 , may be coupled to a portion of speaker module  100 , may be disposed at a suitable location using any other means. As an example, in the configuration of speaker housing member  102  being formed from a dielectric frame that is coated with conductive material at its external surface, the dielectric frame may have an extension that is coupled to and supports antenna feed structure  90 . 
     A sealing member such as sealing member  114  (e.g., a sealant for liquids and/or other substances such as dust, a liquid barrier) may be placed at opening  24  (e.g., on the interior side of device  10 ). Sealing member  114  may provide a water-tight seal and/or a moisture seal that prevents water and/or moisture from entering into the interior of device  10  from the exterior of device  10  through opening  24 . In particular, sealing member  114  may be interposed between opening  24  in sidewall  12 W and opening  104  at speaker housing wall  102 F. If desired, sealing member  114  may be attached to speaker housing wall  102 F or any other support structure instead of sidewall  12 W. 
     If desired, opening  24  and/or opening  104  at speaker housing wall  102 F may include other sealing members or structures that prevention others materials (e.g., other than water) from entering the interior of device  10  from the exterior of device  10 . As an example, opening  24  and/or opening  104  at speaker housing wall  102 F may include mesh structures that prevent dust and other contaminants from entering an interior of device  10  (e.g., from entering an interior of speaker housing member  102 ). If desired, antenna feed structure  90  may be formed on one or more of sealing member  114 , mesh structures, or other (dielectric) support structures disposed in opening  24 , in opening  104 , in cavity  106 , and/or between opening  24  and opening  104 . 
     If desired, device  10  may include a retaining member such as retaining member  116  such as a retaining bracket or other mechanical support structure. Retaining member  116  may surround, fully or only partially, the exterior of one or more speaker housing walls to ensure that speaker module  100  remains in place. For example, retaining member  116  may ensure the opening  24  remains aligned with opening  104 , may ensure that conductive adhesive  112 , sealing member  114 , and/or antenna feed structure  90  remain in place to properly perform their respective functions. Retaining member  116  may be attached to a housing structure such as housing sidewall  12 W by any suitable attachment structures (e.g., screw-based structures, adhesive, etc.). 
     The shape of speaker housing member  102  as described in connection with  FIGS. 6 and 7  is merely illustrative. If desired, speaker housing member  102  may have any other desirable shape (e.g., a shape that is not a cuboid) such as an irregular cuboid shape, a shape having less than six faces, a shape having more than six faces, a shape having any desirable number of straight edges and any number of curved edges, and/or an irregular shape having extension and depressions to accommodate for other components in device  10  (e.g., to accommodate for a shape of housing components in device  10 , to accommodate for internal components of device  10 ) and/or to tune the acoustic frequency response of speaker module  100 . 
     As shown in  FIG. 7 , device  10  may include circuitry  130  at the front face of device  10  and circuitry  140  at the rear face of device  10 . Device  10  may also include other circuitry in the interior of device  10 . As examples, circuitries  130  and  140  may include display circuitry, touch sensor circuitry, antenna circuitry, wireless power circuitry, conductive traces, electronic component modules, and/or any other circuitry for any other functions in device  10  as disclosed in connection with  FIG. 2 . As device  10  may be a small compact device, circuitries  130  and  140  and other internal circuitry may be formed in close proximity to the antenna structures shown in  FIG. 7  such as opening  104  and antenna feed structure  94 . However, because opening  104  (e.g., the slot antenna resonating element for the antenna such as slot element  74  of  FIG. 5 ), antenna feed  62 , and antenna feed structure  90  are formed as part of speaker module  100  and surrounded by the grounded conductive speaker housing walls (to form cavity-backed antenna  40 ), these antenna structures may be isolated from internal components of device  10  (e.g., circuitries  130  and  140 ). 
     By forming antenna  40  based on a cavity-backed and indirectly fed slot antenna resonating element, the cavity-backed and indirectly fed slot antenna is placed in a well-controlled (e.g., well-isolated) location that is shielded from other internal components of device  10 , may have an easy and flexible configuration for tuning the antenna (e.g., by changing the configuration of antenna feeding structure  90 ), and may have a linear polarization in a peak gain direction. Additionally, by providing the cavity-backed and indirectly fed slot antenna as described herein in a compact device such as a wristwatch device, the antenna structures may be appropriately sized (e.g., single continuous opening  24  on one side of sidewall  12 W may be appropriately sized when tuned using antenna feed structure  90 ) to offer frequency coverage at higher frequencies such as frequencies in an ultra-wideband communications band between about 5 GHz and about 8.5 GHz. 
       FIG. 8  is a graph in which antenna performance (antenna efficiency) has been plotted as a function of operating frequency for antennas  40  in device  10  ( FIG. 2 ). As shown in  FIG. 8 , curve  200  plots the antenna efficiency of antennas  40  in device  10  in the absence of the cavity-backed and indirectly fed slot antenna as shown and described in connection with  FIGS. 6 and 7 . As shown by curve  200 , other antenna structures for antennas  40  (e.g., antenna structures formed from display circuitry, formed on rear housing antenna structures, formed from peripheral conductive structures, etc.) may support reasonable antenna efficiencies at relatively low frequencies such as frequencies in the GPS band at 1.5 GHz, the cellular midband from 1.4 GHz to 2.2 GHz, the cellular high band at 2.2 GHz, the 2.4 GHz WLAN/WPAN band, and any other relatively low frequency bands. However, these antenna structures may be unable to provide increased bandwidth to cover relatively high frequencies such as the frequencies in the UWB communications band from about 5.0 GHz to about 8.5 GHz. 
     Curve  202  plots the antenna efficiency of antennas  40  in device  10  in scenarios where the cavity-backed and indirectly fed slot antenna as shown and described in connection with  FIGS. 6 and 7  are present. As shown by curve  202 , the other antenna structures for antennas  40  may still support reasonable antenna efficiencies at relatively low frequencies such as frequencies in the GPS band at 1.5 GHz, the cellular midband from 1.4 GHz to 2.2 GHz, the cellular high band at 2.2 GHz, the 2.4 GHz WLAN/WPAN band, and any other relatively low frequency bands. At the same time, the cavity-backed and indirectly fed slot antenna as shown and described in connection with  FIGS. 6 and 7  may support efficiency peaks at higher frequencies such as frequencies in the UWB communications band from about 5.0 GHz to about 8.5 GHz. In this way, antennas  40  for device  10  may exhibit satisfactory antenna efficiency across each of these bands despite the constrained form factor of device  10 . The example of  FIG. 8  is merely illustrative. In general, efficiency curve  202  may have other shapes. Curve  202  (i.e., antenna  40 ) may exhibit efficiency peaks in any desired number of frequency bands and across any desired frequencies. 
     The foregoing is merely illustrative and various modifications can be made to the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20190926
Publication Date: 20210316
Grant Date: 20210316
Priority Date: 20190926
Inventors: Ruaro, Andrea
DA COSTA BRAS LIMA, EDUARDO JORGE
Martinis, Mario
PAPANTONIS, DIMITRIOS
NATH, JAYESH
PASCOLINI, MATTIA
Assignee: APPLE INC
CPC Classifications: [{"code": "H04M1/035", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04M1/026", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/385", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/2807", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/028", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01Q13/18", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q5/25", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/273", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/44", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q13/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/48", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/273", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/025", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/521", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B1/385", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/385", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/48", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/273", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/025", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q13/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/521", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 74870450