PATENT DOCUMENT

Publication Number: US-10742250-B1
Application Number: US-201916584156-A
Country: US
Kind Code: B1

Title: Electronic devices having integrated antenna structures

Abstract:
An electronic device may include a display formed at a front face and a backside circuitry module formed at a rear face that opposes the front face. The backside circuitry module may be surrounded by coil structures and may be aligned with a protrusion in a rear wall housing at the rear face. The backside circuitry module may include a substrate to which sensor components or other components may be mounted. In particular, sensor circuitry, sensors, transceiver circuitry, connector circuitry, etc. may be mounted to the substrate. Antenna structures may be embedded within the substrate along with conductive paths for the sensor components and other components mounted to the substrate. Support structures in the backside circuitry module may support the substrate, sensor components, and other components. If desired, antenna structures may be formed on the support structures.

Claims:
What is claimed is: 
     
       1. An electronic device comprising:
 a dielectric housing member; 
 a substrate that overlaps the dielectric housing member; 
 a sensor component; 
 a support structure interposed between the substrate and the dielectric housing member, the substrate and the sensor component being mounted to the support structure; and 
 an antenna resonating element for an antenna, the antenna resonating element being embedded within the substrate, aligned with an opening at least partly defined by the support structure, and operable to convey radio-frequency signals through the opening. 
 
     
     
       2. The electronic device defined in  claim 1 , wherein the substrate has first and second opposing surfaces, the electronic device further comprising:
 an electronic component mounted to the first surface of the substrate; and 
 a plurality of layers formed in the substrate and stacked from the second surface of the substrate towards the first surface of the substrate, one layer in the plurality of layers at least partly forming the antenna resonating element. 
 
     
     
       3. The electronic device defined in  claim 2 , further comprising:
 an additional plurality of layers formed in the substrate and interposed between the plurality of layers and the first surface of the substrate, one layer in the additional plurality of layers at least partly forming a radio-frequency transmission line coupled to the antenna resonating element. 
 
     
     
       4. The electronic device defined in  claim 3 , wherein the plurality of layers comprises a metal layer and a dielectric layer, the metal layer at least partly forming the antenna resonating element, and the additional plurality of layers comprises an additional metal layer and an additional dielectric layer, the additional metal layer at least partly forming the radio-frequency transmission line. 
     
     
       5. The electronic device defined in  claim 3 , further comprising:
 a conductive path in the substrate, the conductive path configured to route signals to and from the electronic component, the additional plurality of layers being interposed between the conductive path and the plurality of layers. 
 
     
     
       6. The electronic device defined in  claim 2 , wherein the electronic component comprises radio-frequency transceiver circuitry mounted on the first surface of the substrate, coupled to the antenna resonating element, and operable to convey the radio-frequency signals at a frequency greater than 10 GHz using the antenna resonating element. 
     
     
       7. The electronic device defined in  claim 6 , wherein the radio-frequency transceiver circuitry comprises near-field communications circuitry operable to convey the radio-frequency signals at the frequency greater than 10 GHz using the antenna resonating element. 
     
     
       8. The electronic device defined in  claim 1 , further comprising:
 an additional antenna resonating element for the antenna, the additional antenna resonating element being embedded within the substrate, aligned with an additional opening at least partly defined by the support structure, and operable to convey additional radio-frequency signals through the additional opening, and the antenna resonating element and the additional antenna resonating element being formed on opposing sides of the substrate. 
 
     
     
       9. The electronic device defined in  claim 8 , further comprising:
 coil structures configured to receive wireless power signals, the coil structures surrounding the substrate and at least partly defining the opening and the additional opening. 
 
     
     
       10. The electronic device defined in  claim 8 , wherein the dielectric housing member comprises a rear housing wall, the antenna resonating element and the additional antenna resonating element are configured to convey radio-frequency signals through the rear housing wall, the sensor component is configured to receive signals through the rear housing wall. 
     
     
       11. An electronic device comprising:
 a dielectric rear housing wall; 
 sensor circuitry that overlaps the dielectric rear housing wall; 
 a dielectric support structure configured to mount the sensor circuitry to the dielectric rear housing wall, the dielectric support structure having an opening aligned with the sensor circuitry, the opening having first and second opposing sides; 
 a first antenna resonating element for an antenna, the first antenna resonating element being formed on the first side of the opening; and 
 a second antenna resonating element for the antenna, the second antenna resonating element being formed on the second side of the opening, the first and second antenna resonating elements being operable to convey radio-frequency signals through the dielectric rear housing wall. 
 
     
     
       12. The electronic device defined in  claim 11 , wherein the dielectric support structure includes first and second protruding portions that extend away from the sensor circuitry, the first antenna resonating element being formed on the first protruding portion and separated from the dielectric rear housing wall by a gap and the second antenna resonating element being formed on the second protruding portion and separated from the dielectric rear housing wall by an additional gap. 
     
     
       13. The electronic device defined in  claim 12 , wherein the first and second antenna resonating elements are formed on a first surface of the protruding portion that opposes a second surface of the dielectric support structure, the first surface being interposed between the second surface and the dielectric rear housing wall. 
     
     
       14. The electronic device defined in  claim 13 , wherein the dielectric support structure has a third surface that opposes the second surface, the third surface being coupled to the dielectric rear housing wall. 
     
     
       15. The electronic device defined in  claim 11 , further comprising:
 radio-frequency transceiver circuitry operable to use the first and second antenna resonating elements to convey radio-frequency antenna signals above 10 GHz through the dielectric rear housing wall. 
 
     
     
       16. A wristwatch having a first face and a second face opposite the first face, the wristwatch comprising:
 a display at the first face; 
 a dielectric housing wall at the second face; 
 an antenna resonating element for an antenna, the antenna resonating element overlapping the dielectric housing wall; and 
 radio-frequency transceiver circuitry coupled to the antenna resonating element and operable to use the antenna to convey radio-frequency signals greater than 10 GHz through the dielectric housing wall. 
 
     
     
       17. The wristwatch defined in  claim 16 , further comprising:
 an additional antenna resonating element for an additional antenna, the additional antenna resonating element overlapping the dielectric housing wall; and 
 additional radio-frequency transceiver circuitry coupled to the additional antenna resonating element and operable to use the additional antenna to convey additional radio-frequency signals less than 10 GHz through the dielectric housing wall. 
 
     
     
       18. The wristwatch defined in  claim 16 , further comprising:
 an additional antenna resonating element for the antenna, the additional antenna resonating element overlapping the dielectric housing wall, wherein the radio-frequency transceiver circuitry is coupled to the additional antenna resonating element and is operable to use the antenna resonating element and the additional antenna resonating element to convey the radio-frequency signals greater than 10 GHz through the dielectric housing wall. 
 
     
     
       19. The wristwatch defined in  claim 18 , wherein the radio-frequency signals are associated with debug data, test data, or software data. 
     
     
       20. The wristwatch defined in  claim 16 , wherein the radio-frequency transceiver circuitry is operable to use the antenna to convey the radio-frequency signals at data rates greater than 100 Mbps.

Description:
BACKGROUND 
     This relates to electronic devices, and more particularly, to electronic devices with wireless circuitry. 
     Electronic devices are often provided with wireless communications capabilities. To satisfy consumer demand for small form factor electronic devices, manufacturers are continually striving to implement wireless circuitry such as antenna components using compact structures. 
     At the same time, larger antenna volumes generally allow antennas to exhibit greater efficiency bandwidth. In addition, because antennas have the potential to interfere with each other and with other components in a wireless device, care must be taken when incorporating antennas into an electronic device to ensure that the antennas and wireless circuitry are able to exhibit satisfactory performance over a wide range of operating frequencies. 
     It would therefore be desirable to be able to provide improved wireless circuitry for electronic devices. 
     SUMMARY 
     An electronic device such as a wristwatch may have a front face and rear face. A display may be disposed at the front face and a dielectric rear housing wall (member) may be disposed at the rear face. A backside circuitry module may be formed over the rear housing wall. The backside circuitry module may include a (printed circuit) substrate, sensor components, sensor circuitry and other components. Support structures may be interposed between the substrate and the dielectric housing member. The substrate, sensor components, and sensor circuitry may be mounted to the support structures. Coil structures may surround the backside circuitry module. The substrate may include an opening that accommodates for and/or is aligned with the sensor components and sensor circuitry. The support structures may have one or more openings that accommodates for and/or is aligned with the sensor components and sensor circuitry. 
     In some configurations, an antenna may include a first antenna resonating element embedded within the substrate and a second antenna resonating element embedded within the substrate. The first and second antenna resonating elements may be formed on opposing sides of the substrate (e.g., on opposing sides of the opening in the substrate). The first and second antenna maybe aligned with respective first and second antenna apertures defined by the support structures and the coil structures. The first and second antenna resonating element may be coupled to radio-frequency transceiver circuitry such as near-field communications transceiver circuitry operable to convey radio-frequency antenna signals above 10 GHz through the first and second antenna apertures and the rear housing wall using the first and second antenna resonating elements. 
     The radio-frequency transceiver circuitry may be mounted on a top surface of the substrate. A first plurality of (metal and dielectric) layers may be formed in the substrate and may be stacked from a bottom surface of the substrate towards the top surface of the substrate. The plurality of layers may form the antenna resonating element. A second plurality of (metal and dielectric) layers may be formed in the substrate and interposed between the plurality of layers and the top surface of the substrate. The additional plurality of layers forming a radio-frequency transmission line coupled to the antenna resonating element. 
     In some configurations, an antenna may include a first and second antenna resonating elements formed on opposing sides of a dielectric support structure and/or formed on opposing sides of an opening in the dielectric support structure. The opening in the dielectric support structure may accommodate, surround, and/or be aligned with sensor components and sensor circuitry. The dielectric support structure may include first and second protruding portions that extend away from the opening (e.g., away from the sensor components and sensor circuitry). The first and second antenna resonating elements may be formed on respective bottom surfaces of the first and second protruding portions of the dielectric support structure and may be separated from the rear housing wall by corresponding first and second gaps. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a 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 cross-sectional side view of an illustrative electronic device having antenna elements and sensor circuitry overlapping a rear housing wall in accordance with some embodiments. 
         FIG. 5  is a cross-sectional side view of an illustrative electronic device having antenna elements embedded in a substrate and overlapping a rear housing wall in accordance with some embodiments. 
         FIG. 6  is a perspective view of a substrate such as the substrate shown in  FIG. 5  having embedded antenna elements in accordance with some embodiments. 
         FIG. 7  is a cross-sectional side view of a substrate such as the substrate shown in  FIG. 6  having embedded antenna elements in accordance with some embodiments. 
         FIG. 8  is a cross-sectional side view of an illustrative electronic device having antenna elements formed on a support structure mounted to a rear housing wall in accordance with some embodiments. 
         FIG. 9  is a bottom-up view of a support structure, such as the support structure shown in  FIG. 8  on which antenna elements are formed, in accordance with some embodiments. 
         FIG. 10  is a top-down view of a support structure, such as the support structure shown in  FIG. 8  on which antenna elements are formed, in accordance with some embodiments. 
         FIG. 11  is a plot of antenna performance (antenna efficiency) as a function of frequency showing how an antenna formed from antenna elements in  FIGS. 4-10  may improve antenna efficiency especially at relatively high frequencies in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices such as electronic device  10  of  FIG. 1  may be provided with wireless circuitry (sometimes referred to herein as wireless communications circuitry). The wireless circuitry may be used to support wireless communications in multiple wireless communications bands. Communications bands (sometimes referred to herein as frequency bands) handled by the wireless circuitry can include satellite navigation system communications bands, cellular telephone communications bands, wireless local area network communications bands, wireless personal area network communications bands, near-field communications bands, ultra-wideband communications bands, millimeter wave communications bands, or other wireless communications bands. 
     The wireless circuitry may include one or more antennas. The antennas of the wireless circuitry can include loop antennas, inverted-F antennas, strip antennas, planar inverted-F antennas, patch antennas, slot antennas, monopole antennas, dipole antennas, hybrid antennas that include antenna structures of more than one type, or other suitable antennas. 
     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 housing 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 housing sidewalls  12 W may surround the periphery of device  10  (e.g., conductive housing 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 housing sidewalls  12 W may extend across some or all of the height of device  10  (e.g., parallel to the Z-axis of  FIG. 1 ). Conductive housing sidewalls  12 W and/or 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 layers 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 also be force sensitive and may gather force input data associated with how strongly a user or object is pressing against display  14 . 
     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 (OLED) 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 housing 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. 
     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 of device  10 . Conductive housing sidewalls  12 W 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  24 . Storage circuitry  24  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 include processing circuitry such as processing circuitry  26 . Processing circuitry  26  may be used to control the operation of device  10 . Processing circuitry  26  may include on 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 storage circuitry  24  (e.g., storage circuitry  24  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 storage circuitry  24  may be executed by processing circuitry  26 . 
     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, data transfer 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. 
     Data transfer protocols handled by control circuitry  28  (sometimes referred to herein as data bus protocols) may be used to perform high data rate data transfer operations (e.g., data transfer operations at speeds of 100 Megabits per second (Mbps) or more, at 500 Mbps or more, 1 bit per second or more, etc.). Data transfer protocols that may be implemented by control circuitry  28  may include Universal Serial Bus (USB) protocols, universal asynchronous receiver/transmitter (UART) protocols, Peripheral Component Interconnect (PCI) protocols, Peripheral Component Interconnect Express (PCIe) protocols, Accelerated Graphics Port (AGP) protocols, or any other desired data transfer protocols capable of data speeds (i.e., data rates) of greater than or equal to approximately 100 Mbps. 
     Device  10  may include input-output circuitry  20 . Input-output circuitry  20  may include input-output devices  22 . Input-output devices  22  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  22  may include user interface devices, data port devices (e.g., test port devices), and other input-output components. For example, input-output devices  22  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  22  may include wireless circuitry  34 . Wireless circuitry  34  may include wireless power receiving coil structures such as coil structures  44  and wireless power receiver circuitry such as wireless power receiver circuitry  42 . Device  10  may use wireless power receiver circuitry  42  and coil structures  44  to receive wirelessly transmitted power (e.g., wireless charging signals) from a wireless power adapter (e.g., a wireless power transmitting device such as a wireless charging mat or other device). Coil structures  44  may include one or more inductive coils that use resonant inductive coupling (near field electromagnetic coupling) with a wireless power transmitting coil on the wireless power adapter. 
     The wireless power adapter may pass AC currents through the wireless power transmitting coil to produce a time varying electromagnetic (e.g., magnetic) field that is received as wireless power (wireless charging signals) by coil structures  44  in device  10 . An illustrative frequency for the wireless charging signals is 200 kHz. Other frequencies may be used, if desired (e.g., frequencies in the kHz range, the MHz range, or in the GHz range, frequencies of 1 kHz to 1 MHz, frequencies of 1 kHz to 100 MHz, frequencies less than 100 MHz, frequencies less than 1 MHz, etc.). When the time varying electromagnetic field is received by coil structures  44 , corresponding alternating-current (AC) currents are induced in the coil structures. Wireless power receiver circuitry  42  may include converter circuitry such as rectifier circuitry. The rectifier circuitry may include rectifying components such as synchronous rectification metal-oxide-semiconductor transistors arranged in a bridge network, and may convert these currents from coil structures  44  into a DC voltage for powering device  10 . The DC voltage produced by the rectifier circuitry in wireless power receiver circuitry  42  can be used in powering (charging) an energy storage device such as battery  46  and can be used in powering other components in device  10 . 
     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 antenna(s)  40 , transmission lines, and other circuitry for handling RF wireless signals. Wireless signals can also be sent using light (e.g., using infrared communications). 
     Wireless circuitry  34  may include radio-frequency transceiver circuitry for handling various radio-frequency communications bands. For example, wireless circuitry  34  may include wireless local area network (WLAN) and wireless personal area network (WPAN) transceiver circuitry  32 . Transceiver circuitry  32  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  32  may sometimes be referred to herein as WLAN/WPAN transceiver circuitry  32 . 
     Wireless circuitry  34  may use cellular telephone transceiver circuitry  36  for handling wireless communications in frequency ranges (communications bands) such as a cellular low band (LB) from 600 to 960 MHz, a cellular low-midband (LMB) from 1410 to 1510 MHz, a cellular midband (MB) from 1710 to 2170 MHz, a cellular high band (HB) from 2300 to 2700 MHz, a cellular ultra-high band (UHB) from 3300 to 5000 MHz, or other communications bands between 600 MHz and 5000 MHz or other suitable frequencies (as examples). Cellular telephone transceiver circuitry  36  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  30  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 circuitry  30  are received from a constellation of satellites orbiting the earth. 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  38  (e.g., an NFC transceiver operating at 13.56 MHz or another suitable frequency), etc. 
     In some configurations that are sometimes described herein as an example, near-field communications circuitry  38  may include transceiver circuitry operable at frequencies above about 10 GHz (e.g., at frequencies between about 10 GHz and 300 GHz), and may therefore are sometimes be referred to herein as millimeter/centimeter wave transceiver circuitry. For example, the millimeter/centimeter wave transceiver circuitry may support communications in Extremely High Frequency (EHF) or millimeter wave communications bands between about 30 GHz and 300 GHz and/or in centimeter wave communications bands between about 10 GHz and 30 GHz (sometimes referred to as Super High Frequency (SHF) bands). As an example, near-field communications circuitry  38  may include millimeter/centimeter wave transceiver circuitry operable at about 60 GHz (or any frequency in a millimeter/centimeter wave frequency band) to establish a wireless link useable for data transfer (e.g., between device  10  as a wristwatch and a computer, between device  10  as a wristwatch and another electronic device, between device  10  as a first electronic device and a second electronic device, etc.). If desired, near-field communications circuitry  38  include radio-frequency transceiver circuitry operable at a frequency lower than 10 GHz to establish a wireless link usable for data transfer. In some configurations, non-near-field communications circuitry may be used to support communications in Extremely High Frequency (EHF) or millimeter wave communications bands between about 30 GHz and 300 GHz and/or in centimeter wave communications bands between about 10 GHz and 30 GHz. Wireless data transfer protocols may be used by transceiver circuitry  38  to bidirectionally transfer data at these frequencies. 
     In NFC links, wireless signals are typically conveyed over a few inches at most (e.g., less than five inches, less than four inches, less than three inches, etc.). 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® or Bluetooth® communications band at 5.0 GHz, and one or more cellular telephone communications bands such as a cellular low band between about 600 MHz and 960 MHz and/or a cellular midband between about 1700 MHz and 2200 MHz. 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 electrical 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 electrical 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, and/or other frequencies without the need to incorporate separate bulky antenna structures in device  10 . Conductive portions of housing  12  ( FIG. 1 ) may be used to form part of an antenna ground for one or more antennas  40 . 
     A schematic diagram of wireless circuitry  34  is shown in  FIG. 3 . As shown in  FIG. 3 , wireless circuitry  34  may include transceiver circuitry  48  (e.g., cellular telephone transceiver circuitry  36  of  FIG. 2 , WLAN/WPAN transceiver circuitry  32 , etc.) that is coupled to a given antenna  40  using a radio-frequency transmission line path such as radio-frequency transmission line path  50 . 
     To provide antenna structures such as antenna  40  with the ability to cover different 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 that tune the antenna over communications (frequency) bands of interest. The tunable components may be part of a tunable filter or tunable impedance matching network, may be part of an antenna resonating element, may span a gap between an antenna resonating element and antenna ground, etc. 
     Radio-frequency transmission line path  50  may include one or more radio-frequency transmission lines (sometimes referred to herein simply as transmission lines). Radio-frequency transmission line path  50  (e.g., the transmission lines in radio-frequency transmission line path  50 ) may include a positive signal conductor such as signal conductor  52  and a ground signal conductor such as ground conductor  54 . 
     The transmission lines in radio-frequency transmission line path  50  may, for example, include coaxial cable transmission lines (e.g., ground conductor  54  may be implemented as a grounded conductive braid surrounding signal conductor  52  along its length), stripline transmission lines (e.g., where ground conductor  54  extends along two sides of signal conductor  52 ), a microstrip transmission line (e.g., where ground conductor  54  extends along one side of signal conductor  52 ), coaxial probes realized by a metalized via, edge-coupled microstrip transmission lines, edge-coupled stripline transmission lines, waveguide structures (e.g., coplanar waveguides or grounded coplanar waveguides), combinations of these types of transmission lines and/or other transmission line structures, etc. 
     Transmission lines in radio-frequency transmission line path  50  may be integrated into rigid and/or flexible printed circuit boards. In one suitable arrangement, radio-frequency transmission line path  50  may include transmission line conductors (e.g., signal conductors  52  and ground conductors  54 ) 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 may include components such as inductors, resistors, and capacitors used in matching the impedance of antenna  40  to the impedance of radio-frequency transmission line path  50 . 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. Components such as these may also be used in forming filter circuitry in antenna(s)  40  and may be tunable and/or fixed components. 
     Radio-frequency transmission line path  50  may be coupled to antenna feed structures associated with antenna  40 . As an example, antenna  40  may form an inverted-F antenna, a planar inverted-F antenna, a patch antenna, a loop antenna, or other antenna having an antenna feed  56  with a positive antenna feed terminal such as terminal  58  and a ground antenna feed terminal such as terminal  60 . Positive antenna feed terminal  58  may be coupled to an antenna resonating (radiating) element within antenna  40 . Ground antenna feed terminal  60  may be coupled to an antenna ground in antenna  40 . Signal conductor  52  may be coupled to positive antenna feed terminal  58  and ground conductor  54  may be coupled to ground antenna feed terminal  60 . 
     Other types of antenna feed arrangements may be used if desired. For example, antenna  40  may be fed using multiple feeds each coupled to a respective port of transceiver circuitry  48  over a corresponding transmission line. If desired, signal conductor  52  may be coupled to multiple locations on antenna  40  (e.g., antenna  40  may include multiple positive antenna feed terminals coupled to signal conductor  52  of the same radio-frequency transmission line path  50 ). Switches may be interposed on the signal conductor between transceiver circuitry  48  and the positive antenna feed terminals if desired (e.g., to selectively activate one or more positive antenna feed terminals at any given time). The illustrative feeding configuration of  FIG. 3  is merely illustrative. 
     Device  10  may include multiple antennas that convey radio-frequency signals through different sides of device  10 . For example, device  10  may include at least first antenna that conveys radio-frequency signals through the front face of device  10  (e.g., display  14  of  FIG. 1 ) and a second antenna that conveys radio-frequency signals through the rear face of device  10  (e.g., rear housing wall  12 R of  FIG. 1 ). 
       FIG. 4  is a cross-sectional side view of electronic device  10  showing how a given (first) antenna  40 - 1  may be mounted within device  10  for conveying (radiating) radio-frequency signals through rear housing wall  12 R. As shown in  FIG. 4 , display  14  may form the front face of device  10  whereas rear housing wall  12 R forms the rear face of device  10 . In the example of  FIG. 4 , rear housing wall  12 R is formed from a dielectric material such as glass, sapphire, ceramic, or plastic. This is merely illustrative and, if desired, rear housing wall  12 R may also include conductive portions (e.g., a conductive frame surrounding one or more dielectric windows in rear housing wall  12 R, conductive cosmetic layers, etc.). Conductive housing sidewalls  12 W may extend from the rear face to the front face of device  10  (e.g., from rear housing wall  12 R to display  14 ). 
     Strap  16  may be secured to conductive housing sidewalls  12 W using corresponding attachment structures  70 . Attachment structures  70  may include lugs, spring structures, clasp structures, adhesive structures, or any other desired attachment mechanisms. Strap  16  may be formed using any desired materials (e.g., metal materials, dielectric materials, or combinations of metal and dielectric materials). If desired, strap  16  may be removed from attachment structures  70  (e.g., so that a user of device  10  can swap in different straps having similar or different materials). 
     Display  14  may include a display module  64  (sometimes referred to herein as display stack  64 , display assembly  64 , or active area  64  of display  14 ) and a display cover layer  62 . Display module  64  may, for example, form an active area or portion of display  14  that displays images and/or receives touch sensor input. The lateral portion of display  14  that does not include display module  64  (e.g., portions of display  14  formed from display cover layer  62  but without an underlying portion of display module  64 ) may sometimes be referred to herein as the inactive area or portion of display  14  because this portion of display  14  does not display images or gather touch sensor input. 
     Display module  64  may include conductive components (sometimes referred to herein as conductive display structures) that are used in forming portions of an antenna that radiates through the front face of device  10  (e.g., an antenna having a radiating element such as a radiating slot element defined by display module  64  and/or conductive housing sidewalls  12 W). The conductive display structures in display module  64  may, for example, have planar shapes (e.g., planar rectangular shapes, planar circular shapes, etc.) and may be formed from metal and/or other conductive material that carries antenna currents for a front-facing antenna in device  10 . The conductive display structures may include a frame for display module  64 , pixel circuitry, touch sensor electrodes, an embedded near-field communications antenna, etc. 
     Display cover layer  62  may be formed from an optically transparent dielectric such as glass, sapphire, ceramic, or plastic. Display module  64  may display images (e.g., emit image light) through display cover layer  62  for view by a user and/or may gather touch or force sensor inputs through display cover layer  62 . If desired, portions of display cover layer  62  may be provided with opaque masking layers (e.g., ink masking layers) and/or pigment to obscure the interior of device  10  from view of a user. 
     Substrates such as substrate  66  (e.g., a rigid or flexible printed circuit board, integrated circuit or chip, integrated circuit package, etc.) may be located within the interior of device  10 . Substrate  66  may be, for example, a main logic board (MLB) or other logic board for device  10 . Other components such as components  68  (e.g., components used in forming control circuitry  28  and/or input-output circuitry  20  of  FIG. 2 , battery  46 , etc.) may be mounted to substrate  66  and/or elsewhere within the interior of device  10 . 
     As shown in  FIG. 4 , a given (first) antenna  40 - 1  may be mounted within device  10  for radiating through rear housing wall  12 R. Ground traces  67  may be formed on substrate  66  and may form part of the antenna ground for antenna  40 - 1 . Conductive housing sidewalls  12 W may also form part of the antenna ground for antenna  40 - 1  (e.g., ground traces  67  on substrate  66  may be electrically shorted to conductive housing sidewalls  12 W). Conductive portions of other components in device  10  may also form part of the antenna ground for antenna  40 - 1  (e.g., ground traces  67  on substrate  66 , conductive housing sidewalls  12 W, and/or conductive portions of other components in device  10  may be held at a ground or reference potential). 
     Antenna  40 - 1  may include an antenna resonating element  82  formed from conductive traces on a substrate such as substrate  84 . Substrate  84  may be a plastic substrate, a flexible printed circuit substrate, a rigid printed circuit substrate, a ceramic substrate, or any other desired dielectric substrate. The conductive traces in antenna resonating element  82  (sometimes referred to herein as antenna radiating element  82 , resonating element  82 , radiating element  82 , or antenna element  82 ) may, for example, be patterned onto substrate  84  using a laser direct structuring (LDS) process. In another suitable arrangement, antenna resonating element  82  may be formed from metal foil, layers of sheet metal, conductive portions of the housing for device  10 , etc. 
     Antenna resonating element  82  may be a patch antenna resonating element, an inverted-F antenna resonating element, a planar inverted-F antenna resonating element, a monopole resonating element, a dipole resonating element, a loop resonating element, another type of antenna resonating element, and/or a combination of these types of antenna resonating elements. If desired, antenna resonating element  82  and/or substrate  84  may laterally extend circumferentially around central axis  94  (e.g., antenna resonating element  82  may lie within a given plane or surface and may have a loop shape that extends around an opening, where central axis  94  runs orthogonally through the opening). Positive antenna feed terminal  58  for antenna  40 - 1  may be coupled to antenna resonating element  82 . The ground antenna feed terminal for antenna  40 - 1  (not shown in  FIG. 4  for the sake of clarity) may be coupled to conductive housing sidewalls  12 W, ground traces  67  on substrate  66 , or any other desired portion of the antenna ground for antenna  40 - 1 . 
     Rear housing wall  12 R may extend across substantially all of the length and width of device  10  (e.g., in the X-Y plane). Rear housing wall  12 R may be optically opaque or optically transparent or may include both optically opaque and optically transparent portions (e.g., rear housing wall  12 R may include optically transparent windows in an otherwise optically opaque member). Antenna resonating element  82  may overlap rear housing wall  12 R and may, if desired, be spaced apart from rear housing wall  12 R, pressed against rear housing wall  12 R, adhered to rear housing wall  12 R, etc. In this way, antenna  40 - 1  may be formed at or adjacent to the rear face of device  10  for radiating through rear housing wall  12 R. If desired, antenna resonating element  82  may conform to the shape of the interior surface of rear housing wall  12 R (e.g., antenna resonating element  82  need not be planar). In the example of  FIG. 4 , the interior surface of rear housing wall  12 R has a slightly curved or concave shape (e.g., to form a protruding portion  72  that increases the total volume for components within device  10  relative to scenarios where the interior surface of rear housing wall  12 R is flat). 
     Antenna  40 - 1  may transmit and receive radio-frequency signals (e.g., in at least the cellular low band, the cellular low-midband, the cellular midband, and/or the cellular high band) through rear housing wall  12 R. The radio-frequency signals transmitted by antenna  40 - 1  may be shielded from electrical components  68  and the antenna at the front face of device  10  by ground traces  67  on substrate  66 , for example. Similarly, ground traces  67  and substrate  66  may shield antenna  40 - 1  from components  68  and the antenna at the front face of device  10 , thereby maximizing isolation between the antennas in device  10  despite the relatively small size of device  10 . 
     By forming antenna  40 - 1  at rear housing wall  12 R, the vertical height of device  10  (e.g., parallel to the Z-axis of  FIG. 4 ) may be shorter than would otherwise be possible in scenarios where the corresponding antenna resonating element is located elsewhere on device  10  (while still allowing antenna  40 - 1  to exhibit satisfactory antenna efficiency). As an example, the vertical height of device  10  may be less than or equal to 11.4 mm, less than 15 mm, between 8 and 11.4 mm, or any other desired height while still allowing antenna  40 - 1  to operate with satisfactory antenna efficiency. 
     In practice, the wireless performance of antenna  40 - 1  may be optimized by the presence of an external object adjacent to rear housing wall  12 R. For example, the presence of the user&#39;s wrist  80  adjacent to rear housing wall  12 R when the user is wearing device  10  may enhance the wireless performance of antenna  40 - 1 . During operation, antenna  40 - 1  may transmit and/or receive radio-frequency signals having electric fields (E) that are oriented normal to the surfaces of rear housing wall  12 R and wrist  80 . These signals may sometimes be referred to as surface waves, which are then propagated along the surface of wrist  80  and outwards, as shown by paths  76  (e.g., antenna resonating element  82  and wrist  80  may serve as a waveguide that directs the surface waves outwards). This may allow the radio-frequency signals conveyed by antenna  40 - 1  to be properly received by external communications equipment (e.g., a wireless base station) even though antenna  40 - 1  is located close to wrist  80  and typically pointed away from the external communications equipment. 
     Coil structures  44  may also be mounted within device  10  at or adjacent to rear housing wall  12 R. Coil structures  44  may be spaced apart from rear housing wall  12 R, pressed against rear housing wall  12 R, adhered to rear housing wall  12 R, etc. As shown in  FIG. 4 , antenna  40 - 1  (e.g., antenna resonating element  82 ) may laterally extend around (surround) coil structures  44  (e.g., coil structures  44  may lie within an opening in antenna resonating element  82 ). Coil structures  44  may also circumferentially surround central axis  94  (e.g., coil structures  44  may laterally extend around central axis  94  within the X-Y plane or another surface). In this way, coil structures  44  and antenna  40 - 1  may extend concentrically around central axis  94 . Coil structures  44  may laterally surround module  88  and/or an opening that overlaps module  88 . 
     Coil structures  44  may receive wireless charging signals through rear housing wall  12 R (e.g., when device  10  is placed on a wireless power adapter or other wireless power transmitting device). The wireless charging signals may induce currents on coil structures  44  that are used by wireless power receiver circuitry  42  for charging battery  46  ( FIG. 2 ). Coil structures  44  may include a single conductive coil (e.g., an inductive coil) or more than one conductive coil. In one suitable arrangement, coil structures  44  may include a first coil with windings that coil (wind) around central axis  94  and a second coil with windings that extend perpendicular to the windings in the first coil. The second coil may, for example, include windings that coil (wind) around axis  96  (e.g., a ring-shaped axis that loops around central axis  94  and lies within the X-Y plane). The windings in the first and second coils may include conductive wire (e.g., copper wire), conductive traces, or any other desired conductive material. 
     Coil structures  44  may include ferrite structures such as ferrite structures  86 . Ferrite structures  86  may include ferrite shield structures that help to electromagnetically shield coil structures  44  from other components in device  10 . If desired, ferrite structures  96  may be omitted for one or more portions of coil structures  44 . If desired, ferrite structures  86  may additionally or alternatively include one or more ferrite cores for the windings in coil structures  44  (e.g., the windings in coil structures  44  may be wound around the ferrite core(s)). Ferrite cores in coil structures  44  may help to maximize the wireless charging efficiency for device  10 . 
     Device  10  may include module  88  (sometimes referred to as backside circuitry module  88  or backside control module  88 ) that is mounted on or adjacent to rear housing wall  12 R. Backside circuitry module  88  may include sensor circuitry and may therefore sometimes be referred to herein as sensor module  88 . Central axis  94  may extend (e.g., orthogonally) through a lateral surface of sensor module  88 . Sensor module  88  may be separated from rear housing wall  12 R, pressed against rear housing wall  12 R, adhered to rear housing wall  12 R, etc. Sensor module  88  may overlap protruding portion  72  of rear housing wall  12 R and may be partially or completely located within protruding portion  72  (e.g., defined between the portions of rear housing wall  12 R between dashed lines in  FIG. 4 ). Sensor module  88  may include a rigid printed circuit board, flexible printed circuit, integrated circuit chip, integrated circuit package, plastic substrate, or other substrates for supporting one or more sensors  92  (e.g., one or more sensors  92  may be mounted to a sensor board or a support structure). Sensors  92  may, for example, include sensors in input-output devices  22  of  FIG. 2 . 
     If desired, sensor electrodes may be formed, within, at, or on rear housing wall  12 R (e.g., the sensor electrodes may be at least partially embedded within the dielectric material of rear housing wall  12 R). In this example, the sensor electrodes may be coupled to sensor circuitry in sensor module  88  using one or more conductive paths (not shown in  FIG. 4  for the sake of clarity). The sensor electrodes may, for example, be electrocardiogram (ECG or EKG) electrodes. Sensor circuitry in sensor module  88  may sense the electrical activity of a user&#39;s heart using the sensor electrodes formed within, at, or on rear housing wall  12 R while the user wears device  10 , for example. In another suitable arrangement, the sensor electrodes may be mounted within sensor module  88 . 
     Sensor module  88  may include ground traces (e.g., ground traces in a printed circuit board for sensor circuitry) that are held at a ground or reference potential. If desired, the ground traces in sensor module  88  may be shorted to conductive housing sidewalls  12 W, ground traces  67 , or other ground structures in device  10 . Printed circuit  91  such as a flexible printed circuit may connect to substrate  66  (using connector  78 ) and may connect to sensor module  88  (using connector  90 ). As an example, sensor module  88  may convey sensor signals or other signals to components on substrate  66  (e.g., components  68  such as control circuitry  28  in  FIG. 2 ) via printed circuit  91  and may receive control signals or other signals from the components on substrate  66 . If desired, circuitry other than sensor circuitry in backside circuitry module  88  may also convey and receive data signals or other signals to and from the components on substrate  66 . 
     In general, it may be desirable to remove wired connections or links from device  10  (e.g., connector components in device  10 ) to provide a seamless exterior device surface, to improve device waterproofing, and to optimize useable device interior space by removing bulky connector components, etc. As an example, ports and connectors for receiving wired connections (e.g., configured to convey debug data for debugging various functionalities of device  10 , test data for testing various functionalities of device  10 , and/or other data) may be located at sidewalls  12 W such as at a location near or at where attachment structure  70  is disposed. It may be desirable to remove these ports and connectors for wired connections. 
     It may similar be desirable to migrate from wired connections (e.g., implemented using connector components) to wireless connections or links (e.g., implemented using wireless circuitry  34  in  FIG. 2 ) to maintain and/or improve existing applications of the wired connections. In the above example, it may be desirable to not only remove the ports and connectors for wired connections, but also replace them with wireless connections for conveying debug, test, and/or other data. To maintain and/or improve existing applications of wired connection with wireless connections, the wireless connections may transmit and/or receive data using high data rates in a bidirectional data link (or unidirectional data link) in the near-field domain (e.g., across a distance of less than five inches, less than four inches, less than three inches, etc., rather than in a far-field domain across a distance of greater than five inches, greater than four inches, etc.). As examples, the wireless connections may transmit and receive data using high data rate data transfer operations at speeds of 100 Kilobit per second or more, 1 Megabit per second (Mbps) or more, 100 Mbps or more, at 500 Mbps or more, 1 Gigabit bit per second or more, etc. to satisfactorily replace some wired connections (e.g., wired connection for conveying debug, test, and/or other data). 
     The examples of removing and/or replacing ports and connectors at sidewalls  12 W and replacing wired connections for conveying debug and/or test data are merely illustrative. If desired, it may be similarly desirable to remove and/or replace other wired connections such as USB wired connections or wired connections based on other protocols, or wired connections for conveying other types of signals with wireless connections (e.g., high data rate, bidirectional, and/or near-field wireless connections). 
     Additionally, by providing these wireless connections, device  10  (as an example) may be more easily accessible (e.g., without physical attachment) than in scenarios where device  10  includes the wired counterparts that require physical attachment for access. As examples, by using these wireless connections, device  10  may be configured to receive software updates and debug and test data while still sealed inside a device package or with other member surrounding or enclosing the device, may be configured to transmit and receive debug and test data without concerns for wire misalignment with respect to the debug and test circuitry, etc. 
     Given the limited device interior space, incorporating additional wireless circuitry (e.g., antennas) to implement these wireless connections may require compact and well-integrated antenna element implementations. 
     Still referring to  FIG. 4 , additional wireless circuitry such as a second antenna  40 - 2 , related components for antenna  40 - 2 , and/or other antenna elements may be formed from and/or integrated with components within backside circuitry module  88 . By integrating the additional wireless circuitry within backside circuitry module  88 , device  10  may implement wireless connections in a compact and well-integrated manner. As an example, the additional wireless circuitry within backside circuitry module  88  may be configured to transmit and receive debug and/or test data using high data rate, bidirectional, and/or near-field wireless connections. This is merely illustrative. If desired, the additional wireless circuitry within backside circuitry module  88  (or implemented elsewhere) may be used to provide any suitable wireless connection or link that is useable to transmit and/or convey any suitable type of data. 
       FIG. 5  is a cross-sectional view of electronic device  10  showing how components in backside circuitry module  88  may be disposed within device  10  at rear housing wall  12 R. In the example of  FIG. 5 , a given (second) antenna  40 - 2  may be integrated within backside circuitry module  88  to form an illustrative compact and well-integrated antenna implementation (as described in connection with  FIG. 4 ) and may convey (radiate) radio-frequency signals through rear housing wall  12 R. 
     Backside circuitry module  88  may include a substrate such as substrate  102  (e.g., a rigid or flexible printed circuit board, integrated circuit or chip, integrated circuit package, etc.). Substrate  102  may be a logic board for device  10  such as a sensor logic board. Substrate  102  may have components  104 , which are mounted to a top surface of substrate  102 . Components  104  may include active circuitry such as processing circuitry, sensor circuitry, radio-frequency transceiver circuitry, etc., passive circuitry such as resistors, capacitors, or other passive components, connector structures such as connector  106 , or other components. Components  104  may be implemented as integrated circuit dies or chips, integrated circuit die packages, standalone components, surface mount components, etc. 
     Substrate  102  may include conductive traces formed at surfaces of substrate  102  such as top, bottom, and/or (peripheral and interior) side surfaces and/or conductive traces embedded within substrate  102 . Conductive traces of substrate  102  may (electrically) connect some components on substrate  102  to other components on substrate  102 , may connect components on substrate  102  to components not mounted on substrate  102  (e.g., components mounted on substrate  66 , device housing  12 , other components within backside circuitry module  88 , etc.), or may serve any other suitable interconnect functions. 
     One or more components  104  mounted on substrate  102  may be electrically connected to connector  106  to send and/or receive control signals, data signals, etc. to and/or from circuitry external to backside circuitry module  88 . Connector  106  on substrate  102  may mate with connector  90  on printed circuit  91 . Printed circuit  91  may provide connections between substrate  102  and  66  ( FIG. 4 ). Printed circuit  91  may therefore convey signals between components  104  on substrate  102  and components  68  on substrate  66 . As an example, component  104  may include wireless circuitry such as radio-frequency transceiver circuitry  48  ( FIG. 3 ). Printed circuit  91  may provide connections between radio-frequency transceiver circuitry  48  and a baseband processor on substrate  66 . The baseband processor may convey and/or receive baseband signals from the wireless circuitry (e.g., radio-frequency transceiver circuitry) on substrate  66  within backside circuitry module  88  through printed circuit  91  (and through conductive traces on and/or in substrate  102 ). 
     Substrate  102  may also circumferentially surround central axis  94  (e.g., substrate  102  may laterally extend around central axis  94  within the X-Y plane or another surface). In this way, substrate  102  and coil structures  44  may extend concentrically around central axis  94 . Substrate  102  may laterally surround sensor circuitry  108  (sometimes referred to herein as sensor components  108 ). In other words, substrate  102  may have or define a central opening, in which sensor circuitry  108  is disposed. Sensor circuitry  108  and substrate  102  may be mounted on support structures such as planar support structure  110  (e.g., axis  94  may be perpendicular to support structure  110 ). 
     Vertical support structures  112  (referring to support structures  112 - 1 ,  112 - 2 ,  112 - 3 , and  112 - 4 , collectively) may support planar support structure  110  and may extend parallel to axis  94 . Vertical support structures  112  (sometimes referred to herein as support posts  112 ) may be attached to rear housing wall  12 R via attachment structures such as (pressure-sensitive) adhesive  111 . Support structures  110  and  112  may be formed from dielectric material, conductive material, ceramic material, any suitable material, or any suitable combination of materials. Adhesive  111  may be omitted if desired. 
     If desired, support structure  112 - 1  may be integral with support structure  112 - 4  (e.g., support structure  112 - 1  may be connected to support structure  112 - 4  to form a ring-shaped support structure that circumferentially surround central axis  94 ). The ring-shaped support structure formed from support structures  112 - 1  and  112 - 4  may laterally extend around central axis  94  within the X-Y plane or another surface. Similarly, support structure  112 - 2  may be integral with support structure  112 - 3  (e.g., support structure  112 - 2  may be connected to support structure  112 - 3  to form a ring-shaped structure that circumferentially surround central axis  94 ). The ring-shaped support structure formed from support structures  112 - 2  and  112 - 3  may laterally extend around central axis  94  within the X-Y plane or another surface. The ring-shaped support structure formed form support structures  112 - 1  and  112 - 4  may surround the ring-shaped support structure formed from support structures  112 - 2  and  112 - 3 . If desired, one or more of vertical support structures  112  may be integral with planar support structure  110 . If desired, one or more support structures  112  and/or support structures  110  may be omitted. 
     Support structures  110  and  112  may define chambers in which sensors  92  (referring to sensor  92 - 1 ,  92 - 2 , and  92 - 3 , collectively) are disposed. In particular, support structures  110  and  112  may isolate one sensor from another (e.g., sensor  92 - 1  from sensor  92 - 2 , sensor  92 - 1  from sensor  92 - 3 ). Sensors  92  may also be mounted to support structure  110  (e.g., on an opposing surface from the surface on which substrate  102  and sensor circuitry  108  is mounted). If desired, support structure  110  may include and/or accommodate conductive lines, through which circuitry such as sensor circuitry  108  may be coupled to sensors  92  or through which any suitable interconnection may be provided between components mounted to support structure  110  (e.g., between components mounted on opposing sides of support structure  110 ). 
     Sensors  92  may include one or more sensors such as a light sensor, proximity sensor, touch sensor, or other sensors. As one example, sensor  92 - 1  may include at least one (infrared) light emitter, and sensors  92 - 2  and  92 - 3  may include at least one (infrared) light sensor (e.g., may each include a light sensor). Light emitter  92 - 1  may emit light through rear housing wall  12 R (e.g., through an optically-transparent and/or infrared-transparent window in rear housing wall  12 R). Light sensors  92 - 2  and  92 - 3  may receive a reflected version of the emitted light that has been reflected off of an external object in the vicinity of device  10  such as wrist  80  ( FIG. 4 ) of a user (e.g., a user who is wearing device  10  on their wrist in scenarios where device  10  is a wristwatch). 
     In this example, lens structure  117  may be formed at or on rear housing wall  12 R through which light emitted from light emitter  92 - 1  may travel. Lens structure  117  may be configured to focus the light emitted from light emitter  92 - 1 . Filter structure  118  may be formed at or on rear housing wall  12 R through which reflected light may travel to reach light sensors  92 - 2  and  92 - 3 . Filter structure  118  may be used to pass only light received from selected angles to light sensors  92 - 2  and  92 - 3  to provide optical isolation and to prevent crosstalk from light directed emitted from light emitter  92 - 1 . This example is merely illustrative and, if desired, one or more of sensors  92  may include any other desired components or may be omitted. 
     To form a compact and well-integrated antenna in backside circuitry module  88 , wireless circuitry such as antenna structures may be formed within substrate  102 . As shown in  FIG. 5 , antennas  40 - 2  may include antenna structures  120 - 1  formed in (e.g., embedded within) one lateral side of substrate  102  and antenna structures  120 - 2  formed in (e.g., embedded within) an opposing lateral side of substrate  102 . Antenna structures  120  (referring to antenna structures  120 - 1  and/or  120 - 2 ) embedded within substrate  102  may include antenna resonating elements, parasitic antenna elements, antenna ground structures, antenna feed terminals, antenna short circuit paths, radio-frequency transmission line structures, antenna tuning components, and/or any other suitable antenna elements. 
     Antenna resonating elements embedded in substrate  102  (implemented as antenna structures  120 ) may include dipole antennas, monopole antennas, loop antennas, inverted-F antennas, strip antennas, planar inverted-F antennas, patch antennas, slot antennas, hybrid antennas that include antenna structures of more than one type, or other suitable antennas. In some configurations, the antenna resonating elements embedded in substrate  102  may be backed by antenna ground structures embedded in substrate  102 . The antenna ground structures may be coupled to other antenna ground structures in device  10  (e.g., an antenna ground formed from traces in substrate  66 , conductive housing structures, etc.) if desired. 
     In the example of  FIG. 5 , substrate  102  may have a first (top) surface to which components  104  and connector  106  may be mounted and a second opposing (bottom) surface which is supported by (e.g., mounted on) support structure  110 . The bottom surface of substrate  102  may be interposed between the top surface of substrate  102  and rear housing wall  12 R. Antenna structures  120  may be formed at the bottom surface of substrate  102  such that antenna elements in antenna structures  120  may more easily convey radio-frequency signals through rear housing wall  12 R without interference. In other words, this antenna placement may be more advantageous compared to scenarios in which antenna structures  120  are formed at the top surface of substrate  102  as, in such a scenario, the bottom layers of substrate  102  may include conductive structures that may interfere with antenna operations through rear housing wall  12 R. Additionally, the shorter distance to rear housing wall  12 R from antenna structures  120  implemented at the bottom surface of substrate  120  may also be beneficial in more efficiently conveying antenna signals through rear housing wall  12 R. 
     In some configurations, antenna structures  120 - 1  and antenna structures  120 - 2  may be implemented based on the same type of antenna elements (e.g., have the same number of antenna elements, have the same type of antenna elements, have antenna elements configured in the same manner, have completely mirrored antenna structures, etc.). As an example, antenna structures  120 - 1  and  120 - 2  may both implement the same type of antenna resonating element (e.g., a dipole antenna resonating element, a patch antenna resonating element, etc.), may both implement the same type of parasitic antenna element, and/or may both implement the same embedded antenna ground structure that backs the antenna resonating element. In other configurations, antenna structures  120 - 1  and antenna structures  120 - 2  may be implemented based on different types of antenna elements (e.g., have different numbers of antenna elements, have different types of antenna elements, have antenna elements configured in different manners, have complementary elements that are different from each other, etc.). 
     Antenna structures  120 - 1  for antenna  40 - 2  may transmit and receive radio-frequency signals in direction  116 - 1  through rear housing wall  12 R. Antenna structures  120 - 1  may be aligned with aperture  114 - 1 , which is sometimes referred to herein as opening  114 - 1 , gap  114 - 1 , or slot  114 - 1 . Aperture  114 - 1  may be defined by coil structures  44  on one side and support structures  110  and  112 - 1  on the opposing side, may be defined by other components in backside circuitry module  88 , or may be defined any other components. Similarly, antenna structures  120 - 2  for antenna  40 - 2  may transmit and receive radio-frequency signals in direction  116 - 2  through rear housing wall  12 R. Antenna structures  120 - 2  may be aligned with aperture  114 - 2 , which is sometimes referred to herein as opening  114 - 2 , gap  114 - 2 , or slot  114 - 2 . Aperture  114 - 2  may be defined by coil structures  44  on one side and support structures  110  and  112 - 4  on the opposing side, may be defined by other components in backside circuitry module  88 , or may be defined any other components. 
     Substrate  102  may have inner and outer opposing edges. Inner edges of substrate  102  may be adjacent to and/or may oppose sensor circuitry  108  (e.g., may define an opening in which sensor circuitry  108  is disposed). Outer edges of substrate  102  may be adjacent to and/or may oppose coil structures  40 . Substrate  102  may have a portion adjacent to the outer edges of substrate  102  that overhangs planar support structure  110 . To better align antenna structures  120 - 1  to aperture  114 - 1 , antenna structures  120 - 1  may be embedded in the overhanging portion of substrate  102  and/or may be embedded in a portion of substrate adjacent to a (first) outer edge. To better align antenna structures  120 - 2  to aperture  114 - 2 , antenna structures  120 - 2  may be embedded in the overhanging portion of substrate  102  and/or may be embedded in a portion of substrate adjacent to a (second) outer edge (e.g., opposing the first outer edge). 
       FIG. 6  is a perspective view of substrate  102  in which antenna structures  120 - 1  and  120 - 2  for antenna  40 - 2  may be formed and on which wireless circuitry such as radio-frequency transceiver circuitry  132  (radio-frequency transceiver circuitry  48  in  FIG. 3 ) may be mounted. Other components  104  that may be mounted on substrate  102  are omitted from  FIG. 6  for the sake of clarity. As shown in  FIG. 6 , substrate  102  may have two curved outer edges and two straight outer edges defining an outer outline that accommodates for adjacent structures in device  10  such as coil structures  44  ( FIG. 5 ). Substrate  102  may have four straight inner edge defining an inner opening (e.g., opening  130 ) that accommodates for other adjacent structures in device  10  such as sensor circuitry  108  ( FIG. 5 ). Central axis  94  for electric device  10  may extend through opening  130 . The shape and outline of substrate  102  described in  FIG. 6  is merely illustrative. If desired, substrate  102  may have any suitable shape and/or outline. 
     Antenna structures  120 - 1  and  120 - 2  may be embedded in substrate  102  on opposing sides of opening  130 . In the example of  FIG. 6 , opening  130  may be defined by first and second opposing inner edges of substrate  102  that are substantially parallel to each other, and third and fourth opposing inner edges of substrate  102  that are that substantially parallel to each other that connect the first inner edge to the second inner edge. Antenna structure  120 - 1  may be closest to the first inner edges (on a first side of substrate  102 ), and antenna structures  120 - 2  may be closest to the second inner edges (on a second opposing side of substrate  102 ). Antenna structures  120 - 1  and  120 - 2  may therefore be formed on opposing sides of substrate  102  separated by opening  130 . 
     Additionally, in the example of  FIG. 6 , antenna structures  120 - 1  may be formed at an outer edge (and at a bottom surface of substrate  102 ) on the first side of substrate  102 . Antenna structures  120 - 2  may be formed at an opposing outer edge (and the same bottom surface of substrate  102 ) on the second side of substrate  102 . Antenna structures  120 - 1  and  120 - 2  do not extend to the inner edges of substrate  102  or the top surface of substrate  102  in the example of  FIG. 6 . 
     These examples of the placement of antenna structures  120 - 1  and  120 - 2  are merely illustrative. If desired, antenna structures  120 - 1  and  120 - 2  may be located at any suitable portion of substrate  102 . If desired, one of antenna structures  120 - 1  and  120 - 2  may be omitted and/or additional sets of antenna structures may be embedded in substrate  102 . 
     In some configurations, radio-frequency transceiver circuitry  132  may be mounted on a top surface of substrate  102 . Radio-frequency transceiver circuitry  132  may be any suitable type of transceiver circuitry such as GPS receiver circuitry, WLAN/WPAN transceiver circuitry, cellular telephone transceiver circuitry, near-field communications transceiver circuitry, centimeter and millimeter wave transceiver circuitry, etc. As an example, radio-frequency transceiver circuitry  132  may implement near-field communications transceiver circuitry  38  ( FIG. 2 ) operable at about 60 GHz (or at any other millimeter/centimeter wave frequency or other suitable frequency) or may implement any other types of centimeter and millimeter wave transceiver circuitry. Radio-frequency transceiver circuitry  132  may use antenna structures  120 - 1  and  120 - 2  to transmit and receive debug, test, and/or other signals based on a high data rate, bidirectional, and/or near-field wireless connections for efficient two-way data transfer. 
     One or more conductive paths  134 - 1  may couple radio-frequency transceiver circuitry  132  to antenna structures  120 - 1 . Conductive paths  134 - 1  may form radio-frequency transmission line structures that provide feeding to antenna feed structures in antenna structures  120 - 1 . One or more conductive paths  134 - 2  may couple radio-frequency transceiver circuitry  132  to antenna structures  120 - 2 . Conductive paths  134 - 2  may form radio-frequency transmission line structures (radio-frequency transmission line path  50  in  FIG. 3 ) that provide feeding to antenna feed structures in antenna structures  120 - 2 . Conductive paths  134 - 1  and  134 - 2  may include conductive traces on one or more exterior surfaces of substrate  102 , conductive traces embedded within substrate  102  such as metal layers, vias, or other conductive structures embedded within substrate  102 , wires, conductive fasteners, and/or other conductive structures. 
     Radio-frequency transceiver circuitry  132  may convey radio-frequency antenna signals over conductive paths  134 - 1  and  134 - 2  to antenna structures  120 - 1  and  120 - 2  for antenna  40 - 2 , respectively. If desired, radio-frequency transceiver circuitry  132  coupled to antenna  40 - 2  may implement a half-duplex system by using both of antenna structures  120 - 1  and  120 - 2  to simultaneously receive or simultaneously transmit radio-frequency antenna signals. As an example, the half-duplex system may use both of antenna structures  120 - 1  and  120 - 2  to simultaneously receive large amounts of data (e.g., software, firmware, test data, debug data, etc.), and may thereafter use both of antenna structures  120 - 1  and  120 - 2  to transmit large amounts of data (e.g., acknowledgement data, test data such as test results, etc.). If desired, radio-frequency transceiver circuitry  132  coupled to antenna  40 - 2  may implement a full-duplex system by using one of antenna structures  120 - 1  and  120 - 2  to continually serve a transmit function and by using the other one of antenna structures  120 - 1  and  120 - 2  to continually serve a receive function. As an example, the full-duplex system may use antenna structure  120 - 1  to receive data such as software, firmware, test data, debug data from a transmitting device and simultaneously interact with the transmitting device by using antenna structures  120 - 2  to transmit data (e.g., test results, response or acknowledgement data) back to the transmitting device. 
     In the example of  FIG. 6 , radio-frequency transceiver circuitry  132  may be disposed on as a third side of substrate  102  (between the third inner edge of substrate  102  and a corresponding outer edge of substrate  102 ). The configuration of wireless circuitry (e.g., radio-frequency transceiver circuitry  132  with respect to antenna structures  120 - 1  and  120 - 2 ) in  FIG. 6  is merely illustrative. If desired, radio-frequency transceiver circuitry  132  may be disposed any suitable location on substrate  102 . If desired, radio-frequency transceiver circuitry  132  may be mounted on another substrate other than substrate  102  (e.g., substrate  66  in  FIG. 4 ). If desired, antenna structures  120 - 1  and  120 - 2  may be coupled to two separate transceiver circuitry instead of providing and receiving radio-frequency antenna signals from the same radio-frequency transceiver circuitry  132 . 
       FIG. 7  is a cross-sectional side view of substrate  102  (e.g., as taken across line A-A′ in  FIG. 6 ). Antenna structures  120  may refer to antenna structures  120 - 1  in this cross-sectional view of  FIG. 7 . However, the description for antenna structures  120  in  FIG. 7  may analogously refer to antenna structures  120 - 2  in a corresponding cross-sectional view. Antenna structures  120  may include one or more antenna layers forming antenna resonating (radiating) elements  150  and one or more radio-frequency transmission line layers forming radio-frequency transmission line  152 . 
     The antenna layers may be formed from one or more metal layers (forming one or more antenna resonating elements, parasitic antenna resonating elements, antenna ground structures, antenna feed terminals, etc.), dielectric layers (interposed between and separating the one or more metal layers), vias (connecting some metal layers to other metal layers through the dielectric layers and/or forming one or more antenna resonating elements, parasitic antenna resonating elements, antenna ground structures, antenna feed terminals, etc.) and/or other layers or structures formed from other types of materials. The antenna layers may be formed at a corner of substrate  102  (e.g., the antenna layers are adjacent to a peripheral side surface of substrate  102  and a bottom surface of substrate  102 ). 
     The radio-frequency transmission line layers may be similarly formed from one or more metal layers (forming one or more positive antenna signal paths, ground signal paths, waveguide structures, etc.), dielectric layers (interposed between the separating the one or more metal layers), vias (connecting some metal layers to other metal layers through the dielectric layers, forming one or more positive antenna signal paths, ground signal paths, waveguide structures, etc.) and/or other layers or structures formed from other types of materials. the radio-frequency transmission line layers may be formed adjacent to the peripheral side surface of substrate  102  and may formed over the antenna layers. 
     One or more conductive vias or other conductive structures may couple radio-frequency transmission line  152  to antenna resonating element  150  at one end of radio-frequency transmission line  152 . Radio-frequency transmission line  152  may be coupled to radio-frequency transceiver circuitry  132  at the other end of radio-frequency transmission line (via conductive path  134 ). If desired, the one or more radio-frequency transmission line layers may extend to radio-frequency transceiver circuitry  132  (e.g., to underneath transceiver circuitry  132  and may be connected to radio-frequency transceiver circuitry  132  through one or more via structures). In such a configuration, conductive path  134  may be formed from the one or more radio-frequency transmission line layers in radio-frequency transmission line  152 . 
     A given component  104  may be mounted on a top surface of substrate  102  and disposed over (e.g., on top of) antenna structures  120 . Routing layers  154  directly underneath components  104  may form routing paths  153  for component  104  (that provide signal routing for component  104  to and from other components mounted on substrate  102 ). The radio-frequency transmission line layers for radio-frequency transmission line  152  may be interposed between routing layers  154  and the antenna layers for antenna resonating element  150 . If desired, one or more metal layers (formed as part of the transmission line layers, formed as part of the antenna layers, formed separately from the transmission line layers and the antenna layers, etc.) may be interposed between routing layers  154  and antenna resonating element  150  to provide shielding for antenna resonating element  150  from routing layers  154 . 
     The configuration of the antenna layers for antenna resonating element  150  and transmission line layers for radio-frequency transmission line  152  in  FIG. 7  is merely illustrative. If desired, the antenna layers and the transmission line layers may be instead formed in a vertical direction in substrate  102  (e.g., perpendicular to the horizontal layers shown in  FIG. 7 , instead of the horizontal layers shown in  FIG. 7 ). If desired, via structures may form antenna resonating element  150  and radio-frequency transmission line  152  instead of or in addition to metal layers in substrate  102 . If desired, antenna elements  120  may be embedded within substrate  102  in any suitable manner. 
     By configuring antenna  40 - 2  in the manner described in connection with  FIGS. 5-7 , antenna  40 - 2  may be integrated within backside circuitry module  88  to form compact antenna structures. Antenna structures  120  being embedded within substrate  102  may take up less useable space than in implementations where antenna structures  120 - 1  are formed from separate dedicated antenna structures. Additionally, by aligning antenna structures  120  for antenna  40 - 2  with corresponding apertures and radiating radio-frequency antenna signals through rear housing wall  12 R, satisfactory antenna performance can be achieved. 
       FIG. 8  is a cross-sectional view of electronic device  10  showing how another given (third) antenna  40 - 3  (e.g., as an alternative to antenna  40 - 2  in  FIG. 5 , or if suitable, in addition to antenna  40 - 2  in  FIG. 5 ) may be mounted within device  10  for conveying (radiating) radio-frequency signals through rear housing wall  12 R. In particular, antenna  40 - 3  may be incorporated within backside circuitry module  88 , which includes substrate  102 , components on substrate  102  (e.g., components  104 ), sensor circuitry  108 , sensors  92 , support structures for substrate  102  and sensor circuitry  108 , etc. 
     As shown in  FIG. 8 , antenna  40 - 3  may be formed conductive traces  162 - 1  and  162  on support structure  160 . Support structure  160  (sometimes referred to herein as antenna support structure  160  or dielectric support structure  160 ) may have a ring shape having a central opening in which sensors  92 - 1 ,  9 - 2 , and  92 - 3 , support structures  112 - 2  and  112 - 3 , and other sensor components lie. Support structure  160  may be interposed between planar support structure  110  and rear housing wall  12 R. As such, support structure  160  may support and be attached to support structure  110  on one side and may be attached to rear housing wall  12 R (e.g., via adhesive  164  or any other type of attachment structure) on the opposing side. Support structure  160  may be placed at a similar location as support structures  112 - 1  and  112 - 4  in  FIG. 5  (e.g., may replace support structures  112 - 1  and  112 - 4 , may be incorporated into and/or be formed from portions of support structures  112 - 1  and  112 - 4 ). 
     Support structure  160  may be formed from dielectric material, conductive material, ceramic material, any suitable material, or any suitable combination of materials. As an example, support structure  160  may be formed from a laser direct structuring (LDS) process compatible plastic (sometimes referred to herein as an LDS plastic). Support structure  160  may have a bottom surface  172  that opposes a top surface to which planar support structure  110  is mounted. Adhesive  164  may be applied to bottom surface  172  to attach support structure  160  to rear housing wall  12 R, as an example. Support structure  160  may include a ledge or protruding portion that extends laterally away from axis  94 . The ledge portion may have bottom surface  170  that opposes the top surface to which planar support structure  110  is mounted and that is formed in a different plane (e.g., a different X-Y plane) than bottom surface  172 . If desired, support structure  160  may include two separate ledge portions (or a single continuous ledge portion) on which antenna elements  162 - 1  and  16 - 2  are formed. As such, antenna elements  162 - 1  and  162 - 2  may be separated from rear housing wall  12 R by respective dielectric gaps such as air gaps. 
     Antenna elements such as antenna elements  162 - 1  and  162 - 2  may be formed from conductive material such as conductive metal traces. The metal traces may be pattern onto support structures  160 . As an example, in scenarios where support structure  160  is an LDS plastic, antenna elements  162  may include conductive material formed by the LDS process. If desired, conductive traces for antenna elements  162 - 1  and  162 - 1  may be formed from metal elements mounted to or attached to support structure  160 , may be formed from brackets or other retaining members for supporting backside circuitry module  88 , or may be formed in any other suitable manner. 
     Antenna elements  162 - 1  and  162 - 2  may include antenna resonating elements, parasitic antenna resonating elements, antenna ground elements, antenna feed elements, antenna tuning elements, antenna conductive paths such as short circuit paths, etc. Antenna resonating elements for antenna elements  162 - 1  and  162 - 2  may include dipole antennas, monopole antennas, loop antennas, inverted-F antennas, strip antennas, planar inverted-F antennas, patch antennas, slot antennas, hybrid antennas that include antenna structures of more than one type, or other suitable antennas. 
     If desired, additional antenna elements for antenna  40 - 3  may be formed on other surfaces of support structure  160  (e.g., on surfaces other than surface  170 ). As examples, antenna elements  162 - 1  and  162 - 2  may be formed on a portion of the top surface of support structure  160  that directly opposes (e.g., directly on top of) bottom surface  170 , on a (peripheral) side surface of support structure  160  that connects the top surface to bottom surface  170 , on bottom surface  172  (e.g., adjacent to adhesive  164  and/or forming portions of the attachment structure to rear housing wall  12 R), etc. 
     Antenna elements  162 - 1  and antenna elements  162 - 2  may be formed on opposing sides of support structure  160 . In the example of  FIG. 8 , antenna elements  162 - 1  may be formed at a left peripheral edge of support structure  160  (e.g., on a bottom surface  170  of the ledge portion at the left peripheral edge of support structure  160 ), and antenna elements  162 - 2  may be formed at a right peripheral edge (e.g., on a bottom surface  170  of the ledge portion at the right peripheral edge of support structure  160 ). If desired, surface  170  for the left ledge portion and surface  170  for the right ledge portion may be a continuous planar surface or may be a discontinuous surface. 
     Radio-frequency transceiver circuitry for antenna  40 - 3  may be formed as one of components  104  formed on substrate  102  (or may be formed from components on substrate  66  in  FIG. 4  or formed at any suitable location). The radio-frequency transceiver circuitry for antenna  40 - 3  may be coupled to antenna feeds for antenna  40 - 3 . As an example, antenna  40 - 3  may include a first antenna feed for (e.g., coupled to) antenna elements  162 - 1  and a second antenna feed for (e.g., coupled to) antenna elements  162 - 2 . 
     The radio-frequency transceiver circuitry for antenna  40 - 3  may be any suitable type of transceiver circuitry such as GPS receiver circuitry, WLAN/WPAN transceiver circuitry, cellular telephone transceiver circuitry, near-field communications transceiver circuitry, centimeter and millimeter wave transceiver circuitry, etc. As an example, the radio-frequency transceiver circuitry may implement near-field communications transceiver circuitry  38  ( FIG. 2 ) operable at about 60 GHz (or at any other millimeter/centimeter wave frequency or other suitable frequency) or may implement any other types of centimeter and millimeter wave transceiver circuitry. The radio-frequency transceiver circuitry may use antenna elements  162 - 1  and  162 - 2  to transmit and receive debug, test, and/or other signals based on a high data rate, bidirectional, and/or near-field wireless connections for efficient two-way data transfer. 
     The radio-frequency transceiver circuitry for antenna  40 - 3  may convey radio-frequency antenna signals to antenna elements  162 - 1  and  162 - 1 . If desired, the radio-frequency transceiver circuitry may convey radio-frequency antenna signals over a first set of conductive paths such as radio-frequency transmission lines to antenna elements  162 - 1  and over a second set of conductive paths such as radio-frequency transmission lines to antenna elements  162 - 2 . Antenna elements  162 - 1  may convey and receive radio-frequency antenna signals through a dielectric gap and through rear housing wall  12 R in direction  166 - 1 . The dielectric gap may be defined by a portion of support structure  160 , coil structures  44 , and/or other structures. Antenna elements  162 - 2  may convey and receive radio-frequency antenna signals through another dielectric gap and through rear housing wall  12 R in direction  166 - 2 . The additional dielectric gap may be defined by a portion of support structure  160 , coil structures  44 , and/or other structures. 
     If desired, the radio-frequency transceiver circuitry coupled to antenna  40 - 3  may implement a half-duplex system by using both of antenna structures  162 - 1  and  162 - 2  to simultaneously receive or simultaneously transmit radio-frequency antenna signals. As an example, the half-duplex system may use both of antenna structures  162 - 1  and  162 - 2  to simultaneously receive large amounts of data (e.g., software, firmware, test data, debug data, etc.), and may thereafter use both of antenna structures  162 - 1  and  162 - 2  to transmit large amounts of data (e.g., acknowledgement data, test data such as test results, etc.). If desired, the radio-frequency transceiver circuitry coupled to antenna  40 - 3  may implement a full-duplex system by using one of antenna structures  162 - 1  and  162 - 2  to continually serve a transmit function and by using the other one of antenna structures  162 - 1  and  162 - 2  to continually serve a receive function. As an example, the full-duplex system may use antenna structure  162 - 1  to receive data such as software, firmware, test data, debug data from a transmitting device and simultaneously interact with the transmitting device by using antenna structures  162 - 2  to transmit data (e.g., test results, response or acknowledgement data) back to the transmitting device. 
       FIG. 9  shows a bottom-up view of a support structure on which antenna elements may be formed such as support structure  160  (in  FIG. 8 ). In particular,  FIG. 9  shows a bottom surface of support structure  160  to which rear housing wall  12 R ( FIG. 8 ) is attached when support structure  160  is assembled within device  10 . As shown in  FIG. 9 , dielectric support structure  160  may have ring shape (e.g., may have a shape with a fully enclosed central opening such as opening  161 ). Dielectric support structure  160  may have straight outer (peripheral) edges, curved outer (peripheral) edges, or a combination of straight and curved outer (peripheral) edges. The peripheral edges may define a peripheral outline of support structure  160 . Dielectric support structure  160  may similarly have straight inner (interior) edges, curved inner (interior) edges, or a combination of straight and curved inner (interior) edges surrounding opening  161  in support structure  160 . 
     Adhesive  164  such as pressure-sensitive adhesive may be formed on a portion of the bottom surface of support structure  160 . The portion of the bottom surface of support structure  160  may rest (lie) on rear housing wall  12 R ( FIG. 8 ) when support structure  160  is disposed within device  10 . Support structure  160  may include additional portions of the bottom surface on which antenna elements  162 - 1  and  162 - 2  are formed. 
     As an example, a first additional portion of the bottom surface may be a bottom surface for a ledge portion of support structure  160  (surface  170  in  FIG. 8 ). Antenna elements  162 - 1  may be formed on the first additional portion of the bottom surface. In the example of  FIG. 9 , antenna elements  162 - 1  may include a dipole antenna resonating element formed from conductive structures  180 - 1  and  180 - 2 . As another example, a second additional portion of the bottom surface may be a bottom surface for an additional ledge portion of support structure  160  (surface  170  in  FIG. 8 ). Antenna elements  162 - 2  may be formed on the second additional portion of the bottom surface. In the example of  FIG. 9 , antenna elements  162 - 2  may include a dipole antenna resonating element formed from conductive structures  180 - 3  and  180 - 4 . 
     The two ledge portions of support structure  160  may be separated by opening  161  in support structure  160  (and by the portion of support structure  160  at which adhesive  164  is formed). As such, antenna elements  160 - 1  and  160 - 2  may be formed on opposing sides of support structure  160  separated by opening  161 . If desired, the center of opening  94  may be aligned with a central axis of device  10  (e.g., central axis  94 ) when assembled. The opening may accommodate components within backside circuitry module  88  ( FIG. 8 ) such as sensors  92 , filter structures  118 , lens structures such as lens  117 , or other optical components, other components within backside circuitry module  88 , or other components in device  10 . 
     These examples for forming antenna elements  162 - 1  and  162 - 2  are merely illustrative. If desired, antenna elements  162 - 1  and  162 - 2  may be formed from any suitable types of antenna resonating elements or other antenna elements may be formed. As examples, one or both of antenna elements  162 - 1  and  162 - 2  may be formed from any other suitable antennas. If desired, one of antenna elements  162 - 1  and  162 - 2  may be omitted or additional antenna elements such as additional antenna resonating elements may be formed on support structure  160 . If desired, antenna elements for antenna  40 - 3  may be formed at any suitable location on support structure  160  and/or within backside circuitry module  88  ( FIG. 8 ). As examples, antenna elements may be formed only on one side of the opening in support structure  160  (e.g., one of antenna elements  162 - 1  and  162 - 2  may be omitted, antenna elements may be formed on all four sides of the opening in support structure  160  (e.g., antenna  40 - 3  may include four sets of antenna elements  162  instead of two as shown in  FIG. 9 ). 
       FIG. 10  shows a top-down view of a support structure on which antenna elements may be formed such as support structure  160  (in  FIGS. 8 and 9 ). In particular,  FIG. 10  shows a top surface of support structure  160  on which planar support structure  110  ( FIG. 8 ) and other structures such substrate  102  rests (lies) when support structure  160  is assembled within device  10 . Conductive structures such as conductive structure  182 - 1 ,  182 - 2 ,  182 - 3 , and  182 - 4  may be formed on the top surface of structure  160 . 
     Conductive structure  182 - 1  on the top surface may be coupled to conductive structure  180 - 1  on the (ledge) bottom surface ( FIG. 9 ) using any suitable conductive paths such as a via structure, conductive material on a side surface of support structure  160 , etc. Conductive structure  182 - 2  on the top surface may be coupled to conductive structure  180 - 2  on the (ledge) bottom surface ( FIG. 9 ) using any suitable conductive paths such as a via structure, conductive material on a side surface of support structure  160 , etc. Conductive structures  182 - 1  and  182 - 2  may form antenna respective positive and ground antenna feed terminals for antenna elements  162 - 1  of antenna  40 - 3 . 
     Conductive structure  182 - 3  on the top surface may be coupled to conductive structure  180 - 3  on the (ledge) bottom surface ( FIG. 9 ) using any suitable conductive paths such as a via structure, conductive material on a side surface of support structure  160 , etc. Conductive structure  182 - 4  on the top surface may be coupled to conductive structure  180 - 4  on the (ledge) bottom surface ( FIG. 9 ) using any suitable conductive paths such as a via structure, conductive material on a side surface of support structure  160 , etc. Conductive structures  182 - 3  and  182 - 4  may form antenna respective antenna positive and ground antenna feed terminals for antenna elements  162 - 2  of antenna  40 - 3 . 
     Transmission line structures such as a radio-frequency transmission line (e.g., radio-frequency transmission line  50  in  FIG. 3 ) may be coupled to an antenna feed for antenna  40 - 3  that includes the positive and ground feed terminals formed from conductive structures  182 - 1  and  182 - 2 . Transmission line structures such as an additional radio-frequency transmission line (e.g., radio-frequency transmission line  50  in  FIG. 3 ) may be coupled to an additional antenna feed for antenna  40 - 3  that includes the positive and ground feed terminals formed from conductive structures  182 - 3  and  180 - 4 . Radio-frequency transceiver circuitry such as near-field communications transceiver circuitry  38  or centimeter and millimeter wave transceiver circuitry may be coupled to the transmission line structures to feed the two antenna feeds for antenna  40 - 3 . 
     By forming antenna  40 - 2  ( FIGS. 4-7 ) and/or antenna  40 - 3  ( FIGS. 8-10 ) within backside circuitry module  88  ( FIG. 5  and  FIG. 8 ), compact additional antenna structures may be implemented within device  10  (e.g., to extend the wireless capabilities of device  10 , to replace capabilities of wired connections from device  10 , etc.). Because antennas  40 - 2  and  40 - 3  are integrated into existing structures of backside circuitry module  88 , these additional wireless capabilities are implemented without using much more space within device  10  (e.g., allowing for additional space for other components such as a battery). Additionally, these additional antenna structures (e.g., additional wireless circuitry as implemented by antennas  40 - 2  and  40 - 3 ) may be used to establish high data rate, bidirectional, and/or near-field wireless connections and convey debug data, test data, software data, or other data. 
       FIG. 11  is a plot of antenna efficiency as a function of frequency for antennas  40  in device  10  (e.g., a combination of antennas  40 - 1  in  FIG. 4, 40-2  in  FIGS. 4-7, 40-3  in  FIGS. 8-10 , and/or other antennas  40  in device  10 ). Curve  192  of  FIG. 11  plots the antenna efficiency of antennas  40  without antennas  40 - 2  and  40 - 3 . As shown by curve  192 , antennas  40  without antennas  40 - 2  and  40 - 3  may exhibit a relatively high efficiency within communications band  190  (e.g., between a lower frequency F 1  such as 600 MHz and a higher frequency F 2  such as 10 GHz). At the same time, antennas  40  may exhibit a relatively low antenna efficiency at frequencies greater than frequency F 2  (e.g., within the centimeter and millimeter wave frequency bands, at about the 60 GHz frequency). 
     Curve  194  plots the antenna efficiency of antenna  40  in the presence of antennas  40 - 2  and/or  40 - 3  in  FIGS. 4-10 . As shown by curve  194 , antenna  40 - 2 , antenna  40 - 3 , or a combination of antennas  40 - 2  and  40 - 3  may be operable in the centimeter and millimeter wave frequency bands (e.g., at about the 60 GHz frequency) to increase antenna efficiency at frequencies greater than frequency F 2  (e.g., within the centimeter and millimeter wave frequency bands) relative to scenarios where both antennas  40 - 2  and  40 - 3  are omitted. This may allow antennas  40  in device  10  to convey radio-frequency signals with satisfactory antenna efficiency over a relatively wide range of frequencies (e.g., across the cellular frequency bands, WLAN/WPAN frequency bands, centimeter and millimeter wave frequency bands). 
     The example of  FIG. 11  is merely illustrative. Curves  192  and  194  may have any desired shapes and may exhibit one or more efficiency peaks in any desired number of communications bands at any desired frequencies. As an example, in the presence of antennas  40 - 2  and/or  40 - 3  curve  194  may have a local peak at about 60 GHz in applications where antennas  40 - 2  and  40 - 3  may be used high speed data transfer between device  10  and other devices using near-field communications. 
     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: 20200811
Grant Date: 20200811
Priority Date: 20190926
Inventors: HIEMSTRA, DANIEL J.
NATH, JAYESH
OGILVIE, TIMOTHY B.
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q21/28", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/273", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/385", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/273", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/38", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/40", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q7/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/385", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/38", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/385", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q7/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/40", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/0081", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/273", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/26", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B5/48", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/26", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/48", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 71994033