Electronic Device with Charging-Coil Independent Rear-Facing Antenna

An electronic device may have conductive sidewalls and a rear wall. The rear wall may have a first portion mounted to the sidewalls and a second portion protruding away from the first portion to define a cavity. A sensor board may be mounted within the cavity. A coil structure may be mounted within the cavity and surrounding the sensor board. An antenna may have an antenna ground separated from a patch element by an antenna volume. The patch element may include a first conductive trace on the first portion of the rear wall, a second conductive trace on the sensor board, and a conductive interconnect structure that couples the first conductive trace to the second conductive trace. The coil structure may be disposed outside of the antenna to minimize impact of the coil structure on performance of the antenna.

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 be provided with a housing. The housing may include conductive sidewalls and a rear wall. A display may be mounted to the conductive sidewalls opposite the rear wall. The rear wall may have a first dielectric portion mounted to the conductive sidewalls. The rear wall may have a second dielectric portion that protrudes away from the first dielectric portion and that defines a cavity. A sensor board may be mounted within the cavity. A coil structure may be mounted within the cavity and may laterally surround the sensor board. The coil structure may be used to receive wireless charging signals through the rear wall.

The electronic device may include an antenna that radiates through the rear wall. The antenna may have an antenna ground that includes the conductive sidewalls. The antenna may have a radiating element such as a patch element. The patch element may be separated from the antenna ground by an antenna volume. The patch element may include a first conductive trace on the first dielectric portion of the rear wall. The patch element may include a second conductive trace on the sensor board. The patch element may include a conductive interconnect structure that couples the first conductive trace to the second conductive trace. The conductive interconnect structure may be a conductive bracket or clip. The coil structure may be disposed outside of the antenna volume. Disposing the patch element in this way may maximize the antenna volume and may minimize impact of the coil structure on performance of the antenna.

DETAILED DESCRIPTION

Electronic devices such as electronic device10ofFIG.1may 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, or other wireless communications bands.

The wireless circuitry may include one or more antennas. The antennas of the wireless circuitry can include patch antennas (e.g., shorted patch antennas), loop antennas, inverted-F antennas, strip antennas, planar inverted-F antennas, slot antennas, hybrid antennas that include antenna structures of more than one type, or other suitable antennas.

Electronic device10may 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'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 ofFIG.1, device10is a portable device such as a wristwatch (e.g., a smart watch). Other configurations may be used for device10if desired. The example ofFIG.1is merely illustrative.

In the example ofFIG.1, device10includes a display such as display14. Display14may be mounted in a housing such as housing12. Housing12, 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. Housing12may be formed using a unibody configuration in which some or all of housing12is 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.). Housing12may have metal sidewalls such as sidewalls12W or sidewalls formed from other materials. Examples of metal materials that may be used for forming sidewalls12W include stainless steel, aluminum, silver, gold, metal alloys, or any other desired conductive material. Sidewalls12W may sometimes be referred to herein as housing sidewalls12W or conductive housing sidewalls12W.

Display14may be formed at (e.g., mounted on) the front side (face) of device10. Housing12may have a rear housing wall on the rear side (face) of device10such as rear housing wall12R that opposes the front face of device10. Conductive housing sidewalls12W may surround the periphery of device10(e.g., conductive housing sidewalls12W may extend around peripheral edges of device10). Rear housing wall12R may be formed from conductive materials and/or dielectric materials. Examples of dielectric materials that may be used for forming rear housing wall12R include plastic, glass, sapphire, ceramic, wood, polymer, combinations of these materials, or any other desired dielectrics.

Rear housing wall12R and/or display14may extend across some or all of the length (e.g., parallel to the X-axis ofFIG.1) and width (e.g., parallel to the Y-axis) of device10. Conductive housing sidewalls12W may extend across some or all of the height of device10(e.g., parallel to Z-axis). Conductive housing sidewalls12W and/or rear housing wall12R may form one or more exterior surfaces of device10(e.g., surfaces that are visible to a user of device10) and/or may be implemented using internal structures that do not form exterior surfaces of device10(e.g., conductive or dielectric housing structures that are not visible to a user of device10such 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 device10and/or serve to hide housing walls12R and/or12W from view of the user).

If desired, housing12may include one or more dielectric-filled slots. The dielectric-filled slots, sometimes referred to herein as gaps, openings, or splits, may divide the conductive material in housing12into different conductive housing portions. The slots may be filled with dielectric material such as plastic, polymer, sapphire, glass, rubber, or ceramic. In one implementation that is described herein as an example, housing12may include a slot that extends along three of the four peripheral edges of device10and that separates conductive housing sidewalls12W from a conductive upper portion of housing12(sometimes referred to herein as a conductive turret, conductive top portion, conductive ring, or conductive bezel of housing12) along three sides of device10. The slot may be used to separate a radiating element in an antenna of device10from ground structures in the antenna. This may allow the radiating element to conduct antenna currents along its edges (e.g., at the slot) that produces electric fields associated with the transmission and/or reception of radio-frequency signals.

Display14may 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. Display14may also be force sensitive and may gather force input data associated with how strongly a user or object is pressing against display14.

Display14may 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. Display14may 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 device10, for example.

Device10may include buttons such as button18. There may be any suitable number of buttons in device10(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 housing12(e.g., openings in conductive housing sidewall12W or rear housing wall12R) or in an opening in display14(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 button18may be formed from metal, glass, plastic, or other materials. Button18may sometimes be referred to as a crown in scenarios where device10is a wristwatch device.

Device10may, if desired, be coupled to a strap such as strap16. Strap16may be used to hold device10against a user's wrist (as an example). Strap16may sometimes be referred to herein as wrist strap16. In the example ofFIG.1, wrist strap16is connected to opposing sides of device10. Conductive housing sidewalls12W may include attachment structures for securing wrist strap16to housing12(e.g., lugs or other attachment mechanisms that configure housing12to receive wrist strap16). Wrist strap16may be removable if desired. Configurations that do not include straps may also be used for device10.

A schematic diagram showing illustrative components that may be used in device10is shown inFIG.2. As shown inFIG.2, device10may include control circuitry28. Control circuitry28may include storage such as storage circuitry24. Storage circuitry24may 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 circuitry28may include processing circuitry such as processing circuitry26. Processing circuitry26may be used to control the operation of device10. Processing circuitry26may include on one or more microprocessors, microcontrollers, digital signal processors, host processors, baseband processor integrated circuits, application specific integrated circuits, central processing units (CPUs), graphics processing units, etc. Control circuitry28may be configured to perform operations in device10using hardware (e.g., dedicated hardware or circuitry), firmware, and/or software. Software code for performing operations in device10may be stored on storage circuitry24(e.g., storage circuitry24may 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 circuitry24may be executed by processing circuitry26.

Control circuitry28may be used to run software on device10such 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 circuitry28may be used in implementing communications protocols. Communications protocols that may be implemented using control circuitry28include internet protocols, wireless local area network protocols (e.g., IEEE 802.11 protocols—sometimes referred to as Wi-Fi®), protocols for other short-range wireless communications links such as the Bluetooth® protocol or other wireless personal area network (WPAN) protocols, IEEE 802.11ad protocols, cellular telephone protocols, MIMO protocols, antenna diversity protocols, satellite navigation system protocols (e.g., global positioning system (GPS) protocols, global navigation satellite system (GLONASS) protocols, etc.), IEEE 802.15.4 ultra-wideband communications protocols or other ultra-wideband communications protocols, etc. Each communications protocol may be associated with a corresponding radio access technology (RAT) that specifies the physical connection methodology used in implementing the protocol.

Device10may include input-output circuitry20. Input-output circuitry20may include input-output devices22. Input-output devices22may be used to allow data to be supplied to device10and to allow data to be provided from device10to external devices. Input-output devices22may include user interface devices, data port devices, and other input-output components. For example, input-output devices22may 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 circuitry22may include wireless circuitry34. Wireless circuitry34may include wireless power receiving coil structures such as coil structures44and wireless power receiver circuitry such as wireless power receiver circuitry42. Device10may use wireless power receiver circuitry42and coil structures44to 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 structures44(sometimes referred to herein as coil44) 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 structures44in device10. 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 structures44, corresponding alternating-current (AC) currents are induced in the coil structures. Wireless power receiver circuitry42may 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 structures44into a DC voltage for powering device10. The DC voltage produced by the rectifier circuitry in wireless power receiver circuitry42can be used in powering (charging) an energy storage device such as battery46and can be used in powering other components in device10.

To support wireless communications, wireless circuitry34may include baseband circuitry (e.g., one or more baseband processors or other circuitry that operates on baseband signals) and radio-frequency (RF) transceiver circuitry formed from one or more integrated circuits, power amplifier circuitry, low-noise input amplifiers, passive RF components, mixer circuitry, synthesizers, modulators, demodulators, upconverters, downconverters, etc. Wireless circuitry34may also include one or more antennas such as antennas40, transmission lines, and other circuitry for handling RF wireless signals. One or more radio-frequency front end modules may be disposed along the transmission lines if desired. Wireless signals can also be sent using light (e.g., using infrared communications).

Wireless circuitry34may include radio-frequency transceiver circuitry for handling transmission and/or reception of radio-frequency signals within corresponding frequency bands at radio frequencies (sometimes referred to herein as communications bands or simply as “bands”). For example, wireless circuitry34may include wireless local area network (WLAN) and wireless personal area network (WPAN) transceiver circuitry32. Transceiver circuitry32may handle a 2.4 GHz WLAN band (e.g., from 2400 to 2480 MHz), a 5 GHz WLAN band (e.g., from 5180 to 5825 MHz), a Wi-Fi® 6E band (e.g., from 5925-7125 MHz), and/or other Wi-Fi® bands (e.g., from 1875-5160 MHz). Transceiver circuitry32may sometimes be referred to herein as WLAN/WPAN transceiver circuitry32.

Wireless circuitry34may use cellular telephone transceiver circuitry36for 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, 2G bands, 3G bands, 4G LTE bands, 3GPP 5G New Radio Frequency Range 1 (FR1) bands below 10 GHz, 3GPP 5G New Radio (NR) Frequency Range 2 (FR2) bands between 20 and 60 GHz, or other centimeter or millimeter wave frequency bands between 10-300 GHz (as examples). Cellular telephone transceiver circuitry36may handle voice data and non-voice data.

Wireless circuitry34may include satellite navigation system circuitry such as Global Positioning System (GPS) receiver circuitry30. GPS receiver circuitry30may receive GPS signals in satellite navigation frequency bands such as the Global Positioning System (GPS) L1 band (e.g., at 1575 MHz), L2 band (e.g., at 1228 MHz), L3 band (e.g., at 1381 MHz), L4 band (e.g., at 1380 MHz), and/or L5 band (e.g., at 1176 MHz), a Global Navigation Satellite System (GLONASS) band, a BeiDou Navigation Satellite System (BDS) band, or other bands. Satellite navigation system signals for receiver circuitry30are received from a constellation of satellites orbiting the earth. Wireless circuitry34can include circuitry for other short-range and long-range wireless links if desired. For example, wireless circuitry34may include circuitry for receiving television and radio signals, paging system transceivers, near field communications (NFC) transceiver circuitry38(e.g., an NFC transceiver operating at 13.56 MHz or another suitable frequency), ultra-wideband transceiver circuitry (e.g., transceiver circuitry that operates at ultra-wideband (UWB) frequency bands under the IEEE 802.15.4 protocol and/or other ultra-wideband communications protocols (e.g., a first UWB communications band at 6.5 GHz and/or a second UWB communications band at 8.0 GHz)), transceiver circuitry that operates using communications bands under the family of 3GPP wireless communications standards, transceiver circuitry that operates using communications bands under the IEEE 802.XX family of standards, transceiver circuitry that operates using industrial, scientific, and medical (ISM) bands such as an ISM band between around 900 MHz and 950 MHz or other ISM bands below or above 1 GHz, transceiver circuitry that operates using one or more unlicensed bands, transceiver circuitry that operates using one or more bands reserved for emergency and/or public services, and/or any other desired frequency bands of interest. Wireless circuitry34may also be used to perform spatial ranging operations if desired.

In NFC links, wireless signals are typically conveyed over a few inches at most. In satellite navigation system links, cellular telephone links, and other long-range links, wireless signals are typically used to convey data over thousands of feet or miles. In WLAN and WPAN links at 2.4 and 5 GHz and other short-range wireless links, wireless signals are typically used to convey data over tens or hundreds of feet. Antenna diversity schemes may be used if desired to ensure that the antennas that have become blocked or that are otherwise degraded due to the operating environment of device10can be switched out of use and higher-performing antennas used in their place. Multiple-input and multiple-output (MIMO) schemes and/or carrier aggregation (CA) schemes may be used to boost data rates and wireless performance.

Wireless circuitry34may include antennas40. Antennas40may be formed using any suitable antenna types. For example, antennas40may include antennas with resonating elements that are formed from patch antenna structures (e.g., shorted patch antenna structures), slot antenna structures, loop 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 antennas40may be cavity-backed antennas. Two or more antennas40may be arranged in a phased antenna array if desired (e.g., for conveying centimeter and/or millimeter wave signals within a signal beam formed in a desired beam pointing direction that may be steered/adjusted over time).

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 device10by using a single antenna to handle two or more different communications bands. If desired, a combination of antennas for covering multiple frequency bands and dedicated antennas for covering a single frequency band may be used. For example, a first antenna40in device10may be used to handle communications in a WiFi® or Bluetooth® communication band at 2.4 GHz, a GPS L1 band at 1575 MHz, a GPS L5 band at 1176 MHz, and one or more cellular telephone communications bands such as a cellular midband (MB) from 1710 to 2170 MHz, a cellular high band (HB) from 2300 to 2700 MHz, whereas a second antenna40in device10is used to handle communications in a cellular low band (LB) and the cellular HB.

It may be desirable to implement at least some of the antennas in device10using 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 produce antenna currents in components such as display14(FIG.1), so that display14and/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 device10. Conductive portions of housing12(FIG.1) may be used to form part of an antenna ground for one or more antennas40.

While control circuitry28is shown separately from wireless circuitry34in the example ofFIG.1for the sake of clarity, wireless circuitry34may include processing circuitry (e.g., one or more processors) that forms a part of processing circuitry26and/or storage circuitry that forms a part of storage circuitry24of control circuitry28(e.g., portions of control circuitry28may be implemented on wireless circuitry34). As an example, control circuitry28may include baseband circuitry (e.g., one or more baseband processors), digital control circuitry, analog control circuitry, and/or other control circuitry that forms part of radio wireless circuitry34. The baseband circuitry may, for example, access a communication protocol stack on control circuitry28(e.g., storage circuitry24) to: perform user plane functions at a PHY layer, MAC layer, RLC layer, PDCP layer, SDAP layer, and/or PDU layer, and/or to perform control plane functions at the PHY layer, MAC layer, RLC layer, PDCP layer, RRC, layer, and/or non-access stratum layer. If desired, the PHY layer operations may additionally or alternatively be performed by radio-frequency (RF) interface circuitry in wireless circuitry34.

A schematic diagram of wireless circuitry34is shown inFIG.3. As shown inFIG.3, wireless circuitry34may include transceiver circuitry48(e.g., cellular telephone transceiver circuitry36ofFIG.2, WLAN/WPAN transceiver circuitry32, etc.) that is coupled to a given antenna40using a radio-frequency transmission line path such as radio-frequency transmission line path50.

To provide antenna structures such as antenna40with the ability to cover different frequencies of interest, antenna40may 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, antenna40may 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 path50may include one or more radio-frequency transmission lines (sometimes referred to herein simply as transmission lines). Radio-frequency transmission line path50(e.g., the transmission lines in radio-frequency transmission line path50) may include a positive signal conductor such as signal conductor52and a ground signal conductor such as ground conductor54.

The transmission lines in radio-frequency transmission line path50may, for example, include coaxial cable transmission lines (e.g., ground conductor54may be implemented as a grounded conductive braid surrounding signal conductor52along its length), stripline transmission lines (e.g., where ground conductor54extends along two sides of signal conductor52), a microstrip transmission line (e.g., where ground conductor54extends along one side of signal conductor52), 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 path50may be integrated into rigid and/or flexible printed circuit boards. In one suitable arrangement, radio-frequency transmission line path50may include transmission line conductors (e.g., signal conductors52and ground conductors54) 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 antenna40to the impedance of radio-frequency transmission line path50. 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)40and may be tunable and/or fixed components.

Radio-frequency transmission line path50may be coupled to antenna feed structures associated with antenna40. As an example, antenna40may form an inverted-F antenna, a planar inverted-F antenna, a patch antenna, a loop antenna, or other antenna having an antenna feed56with a positive antenna feed terminal such as terminal58and a ground antenna feed terminal such as terminal60. Positive antenna feed terminal58may be coupled to an antenna resonating (radiating) element within antenna40. Ground antenna feed terminal60may be coupled to an antenna ground in antenna40. Signal conductor52may be coupled to positive antenna feed terminal58and ground conductor54may be coupled to ground antenna feed terminal60.

Other types of antenna feed arrangements may be used if desired. For example, antenna40may be fed using multiple feeds each coupled to a respective port of transceiver circuitry48over a corresponding transmission line. If desired, signal conductor52may be coupled to multiple locations on antenna40(e.g., antenna40may include multiple positive antenna feed terminals coupled to signal conductor52of the same radio-frequency transmission line path50). Switches may be interposed on the signal conductor between transceiver circuitry48and 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 ofFIG.3is merely illustrative.

The term “convey radio-frequency signals” as used herein means the transmission and/or reception of the radio-frequency signals (e.g., for performing unidirectional and/or bidirectional wireless communications with external wireless communications equipment). Antennas40may transmit the radio-frequency signals by radiating the radio-frequency signals into free space (or to free space through intervening device structures such as a dielectric cover layer). Antennas40may additionally or alternatively receive the radio-frequency signals from free space (e.g., through intervening devices structures such as a dielectric cover layer). The transmission and reception of radio-frequency signals by antennas40each involve the excitation or resonance of antenna currents on an antenna resonating element in the antenna by the radio-frequency signals within the frequency band(s) of operation of the antenna.

Device10may include multiple antennas that convey radio-frequency signals through different sides of device10. For example, device10may include at least first antenna40that conveys radio-frequency signals through the front face of device10(e.g., display14ofFIG.1) and a second antenna40that conveys radio-frequency signals through the rear face of device10(e.g., rear housing wall12R ofFIG.1).

Any desired antenna structures may be used for implementing the antenna40that conveys radio-frequency signals through the rear face of device10. In one suitable arrangement that is sometimes described herein as an example, patch antenna structures may be used for implementing the antenna40that conveys radio-frequency signals through the rear face of device10. Antennas that are implemented using patch antenna structures may sometimes be referred to herein as patch antennas. An illustrative patch antenna that may be used to convey radio-frequency signals through the rear face of device10is shown inFIG.4.

As shown inFIG.4, antenna40may have a radiating patch element such as patch element66that is separated from and parallel to an antenna ground such as antenna ground62(sometimes referred to herein as ground plane62or ground structures62). Patch element66may lie within a plane such as the X-Y plane ofFIG.4(e.g., the lateral surface area of patch element66may lie in the X-Y plane). Patch element66may sometimes be referred to herein as patch antenna resonating element66, patch resonating element66, patch resonator66, shorted patch antenna resonating element66, patch66, patch radiating element66, patch antenna radiating element66, shorted patch antenna radiating element66, patch radiator66, antenna resonating element66, or antenna radiating element66.

Antenna ground62may lie within a plane that is parallel to the plane of patch element66. Patch element66and antenna ground62may therefore lie in separate parallel planes that are separated by a distance (height) H. Antenna ground62may be formed from conductive traces patterned on a dielectric substrate such as a rigid or flexible printed circuit board substrate, metal foil, stamped sheet metal, electronic device housing structures, or any other desired conductive structures (e.g., ground structures). Patch element66may be formed from conductive traces patterned on a dielectric housing wall, conductive traces patterned on a sensor board (e.g., a rigid or flexible printed circuit board), and from conductive interconnect structures (e.g., a conductive bracket) that couples the conductive traces together, as one example.

The length of the sides of patch element66may be selected so that antenna40resonates (radiates) at desired operating frequencies. For example, the sides of patch element66may each have a length that is approximately equal to half of the wavelength of the signals conveyed by antenna40(e.g., the effective wavelength given the dielectric properties of the materials surrounding patch element66). Positive antenna feed terminal58may be coupled to patch element66(e.g., at a feed edge of patch element66). Antenna current for antenna40may flow along the perimeter of patch element66, as shown by arrow68. The antenna current may be produced by positive antenna feed terminal58(e.g., during signal transmission) or by incident radio-frequency signals received by antenna40. During signal reception, the antenna current may pass the radio-frequency signals to transceiver circuitry on device10via positive antenna feed terminal58.

The example ofFIG.4is merely illustrative. Patch element66may have a square shape in which all of the sides of patch element66are the same length or may have a different rectangular shape. Patch element66may be formed in other shapes having any desired number of straight and/or curved edges (e.g., a round shape, an elliptical shape, a polygonal shape, etc.). Patch element66may be shorted to antenna ground62using one or more grounding structures. Antenna40may be implemented using other antenna architectures. Patch element66of antenna40may be formed from multiple conductive structures in device10in a manner that serves to integrate patch element66into device10in a way that allows antenna40to convey radio-frequency signals through the rear face of device10.

FIG.5is a cross-sectional side view showing how patch element66may be formed from multiple conductive structures and integrated into device10for conveying radio-frequency signals through the rear face of device10. As shown inFIG.5, display14may form the front face of device10whereas rear housing wall12R forms the rear face of device10. In the example ofFIG.5, rear housing wall12R is formed from a dielectric material such as glass, sapphire, zirconia, ceramic, or plastic. This is merely illustrative and, if desired, rear housing wall12R may also include conductive portions (e.g., a conductive frame surrounding one or more dielectric windows in rear housing wall12R, conductive cosmetic layers, etc.). Conductive housing sidewalls12W may extend from the rear face to the front face of device10(e.g., from rear housing wall12R to display14).

Display14may include a display module72(sometimes referred to herein as display stack72, display assembly72, display board72, or active area72of display14) and a display cover layer100. Display module72may, for example, form an active area or portion of display14that displays images and/or receives touch sensor input. The lateral portion of display14that does not include display module72(e.g., portions of display14formed from display cover layer100but without an underlying portion of display module72) may sometimes be referred to herein as the inactive area or portion of display14because this portion of display14does not display images or gather touch sensor input.

Display module72may 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 device10(e.g., an antenna having a radiating element such as a shorted patch element that includes display module72and conductive portions of housing12). Display cover layer100may be formed from an optically transparent dielectric such as glass, sapphire, ceramic, or plastic. Display module72may display images (e.g., emit image light) through display cover layer100for view by a user and/or may gather touch or force sensor inputs through display cover layer100. If desired, portions of display cover layer100may be provided with opaque masking layers (e.g., ink masking layers) and/or pigment to obscure the interior of device10from view of a user.

Substrates such as substrate74(e.g., a rigid or flexible printed circuit board, integrated circuit or chip, integrated circuit package, etc.) may be located within the interior of device10. Substrate74may be, for example, a main logic board (MLB) or other logic board for device10. Other components such as components70(e.g., components used in forming control circuitry28and/or input-output circuitry20ofFIG.2, battery46, etc.) may be mounted to substrate74and/or elsewhere within the interior of device10.

Rear housing wall12R may extend across substantially all of the length and width of device10(e.g., in the X-Y plane). Rear housing wall12R may be optically opaque or optically transparent or may include both optically opaque and optically transparent portions (e.g., rear housing wall12R may include optically transparent windows in an otherwise optically opaque member). In the example ofFIG.5, rear housing wall12R includes a first dielectric wall80and a dielectric protrusion formed from a second dielectric wall82that extends vertically downward from first dielectric wall80. First dielectric wall80and second dielectric wall82may sometimes also be referred to herein respectively as first and second portions of rear housing wall12R or first and second dielectric portions of rear housing wall12R.

First dielectric wall80may define part of the interior cavity of device10. Second dielectric wall82may define part of a sensor cavity84between first dielectric wall80and second dielectric wall82. First and second dielectric walls80and82may be formed from ceramic, plastic, glass, sapphire, and/or any other desired dielectric materials. First and second dielectric walls80and82may be formed from respective portions of a single integrated piece of dielectric material or may be formed from separate pieces of dielectric material that have been adhered, joined, fused, attached, secured, or otherwise affixed together at the rear face of device10. While the example ofFIG.5shows a portion of first dielectric wall80protruding over sensor cavity84, this is merely illustrative. If desired, first dielectric wall80may extend continuously into second dielectric wall82without extending over sensor cavity84. First dielectric wall80may substantially extend within a first plane. Second dielectric wall82may substantially extend within a second plane below the first plane (e.g., parallel to the first plane) and may include sidewalls that couple the portion of second dielectric wall82in the second plane to first dielectric wall80. This is merely illustrative and, in general, second dielectric wall82and thus sensor cavity84may have any desired shape.

The protrusion formed by second dielectric wall82(e.g., sensor cavity84) may accommodate one or more components for device10. For example, a sensor board such as sensor board88may be disposed within sensor cavity84(e.g., between the first and second planes). Device10may have a central axis98that extends (e.g., orthogonally) through a lateral surface of sensor board88. Sensor board88may be separated from second dielectric wall82, pressed against second dielectric wall82, or adhered to second dielectric wall82, etc. Sensor board88may be disposed entirely within sensor cavity84or, if desired, part of sensor board88may be disposed above sensor cavity84(e.g., within the interior cavity of device10at or above the first plane).

Sensor board88may 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 sensors94(e.g., one or more sensors94may be mounted to sensor board88). Sensors94may, for example, include sensors in input-output devices22ofFIG.2. Sensors94may include optical sensors such as one or more optical transmitters and one or more optical receivers. The optical transmitters may transmit optical signals (e.g., visible light, infrared light, etc.) through one or more optically transparent windows or portions of second dielectric wall82. The optical receivers may receive optical signals through the one or more optically transparent windows or portions of second dielectric wall82. The optical sensors may, for example, be used to measure a user's heart rate or blood oxygen level when the user is wearing device10on their body. If desired, sensors94may include sensor electrodes that protrude through second dielectric wall82such as electrocardiogram (ECG or EKG) electrodes. Sensor circuitry on sensor board88may sense the electrical activity of a user's heart using the sensor electrodes while the user wears device10, for example. Sensors94may also include one or more sensors such as a light sensor, proximity sensor, touch sensor, or other sensors.

Coil structures44may also be disposed within sensor cavity84(e.g., between the first and second planes). Coil structures44may laterally (circumferentially) surround sensor board88and central axis98. Coil structures44may include windings of wire that wrap around central axis98and sensor board88(e.g., in planes parallel to the X-Y plane), may include one or more windings of wire warped around a ferrite core that laterally extends around central axis98, or may include any other desired inductive coil structures for receiving wireless charging signals. Coil structures44may include a single conductive coil (e.g., an inductive coil) or more than one conductive coil. In one suitable arrangement, coil structures44may include a first coil with windings that coil (wind) around central axis98(e.g., in the direction of arrow106) and a second coil with windings that extend perpendicular to the windings in the first coil. The windings in the first and second coils may include conductive wire (e.g., copper wire), conductive traces, or any other desired conductive material. In general, coil structures44may include any desired number of windings of wire, any desired number of coils, any desired number of ferrite cores, etc. If desired, a ferrite shield structure (not shown) that helps to electromagnetically shield coil structures44from other components in device10may be layered over coil structures44. Coil structures44may receive wireless charging signals through second dielectric wall82(e.g., when device10is placed on a wireless power adapter or other wireless power transmitting device). The wireless charging signals may induce currents on coil structures44that are used by wireless power receiver circuitry42for charging battery46(FIG.2).

Antenna40may be disposed within device10for radiating through rear housing wall12R. In general, the volume of antenna40may be proportional to the efficiency bandwidth of the antenna. Antenna40may include a patch element66and an antenna ground (e.g., antenna ground62ofFIG.4) separated from patch element66by antenna volume86. Ground traces76may be formed on substrate74and may form part of the antenna ground for antenna40(e.g., antenna ground62ofFIG.4). Conductive housing sidewalls12W may also form part of the antenna ground for antenna40(e.g., ground traces76on substrate74may be electrically shorted to conductive housing sidewalls12W). Conductive portions of other components in device10may also form part of the antenna ground for antenna40(e.g., ground traces76on substrate74, conductive housing sidewalls12W, and/or conductive portions of other components in device10may be held at a ground or reference potential).

To maximize antenna volume86, patch element66may be distributed between multiple conductive structures and planes in device10. As shown inFIG.5, patch element66may include first conductive traces78, second conductive traces90, and a conductive interconnect structure such as conductive interconnect structure92(sometimes referred to herein simply as conductive interconnect92). First conductive traces78may sometimes be referred to herein in the singular as first conductive trace78. Similarly, second conductive traces90may sometimes be referred to herein in the singular as second conductive trace90. First conductive traces may be patterned onto the interior surface of first dielectric wall80(e.g., using a laser-direct-structuring (LDS) process). Second conductive traces90may be patterned onto a surface of sensor board88. In other implementations, first conductive traces78and/or second conductive traces90may be patterned onto one or more flexible printed circuits that are layered over first dielectric wall80and/or sensor board88.

Conductive interconnect structure92may couple first conductive traces78on first dielectric wall80to second conductive traces90on sensor board88. First conductive traces78may laterally extend around central axis98(e.g., in the direction of arrow106). To maximize the antenna volume86of antenna40, first conductive traces78may extend across all or substantially all of the interior surface of first dielectric wall80. Similarly, second conductive traces90may extend across all or substantially all of the lateral surface of sensor board88. If desired, a portion of first conductive traces78may overlap a portion of second conductive traces90(e.g., when viewed in the −Z direction).

Conductive interconnect structure92may include a conductive spring, a conductive pin, metal wire, stamped sheet metal, a conductive pin, conductive adhesive, solder, a weld, a conductive clip, a wire, conductive foam, conductive traces (e.g., on an underlying flexible printed circuit), a conductive bracket, conductive portions of the housing of device10, and/or any other desired conductive material that electrically couplers first conductive traces78to second conductive traces90. In one implementation that is described herein as an example, conductive interconnect structure92is a conductive bracket or clip (e.g., a bent piece of metal) that extends from first conductive traces78and that presses against second conductive traces90, thereby creating a robust and stable electrical connection between first conductive traces78and second conductive traces90.

Positive antenna feed terminal58may be coupled to first conductive traces78. Corresponding antenna currents may flow along first conductive traces78, through conductive interconnect structure92, and along second conductive traces90as shown by arrow96. In this way, first conductive traces78, second conductive traces90, and conductive interconnect structure92may collectively form the patch element66of antenna40. First conductive traces78, second conductive traces90, and conductive interconnect structure92may therefore resonate at radio frequencies to convey radio-frequency signals through rear housing wall12R. In general, only one conductive interconnect structure is needed to electrically integrate second conductive traces90into patch element66. However, this is merely illustrative. If desired, there may be more than one conductive interconnect structure92that couples first conductive traces78to second conductive traces90(e.g., at different points around central axis98).

Distributing patch element66across both the interior surface of first dielectric wall80and sensor board88within sensor cavity84in this way (e.g., using conductive interconnect structure92) may serve to maximize the antenna volume86of antenna40and thus its efficiency bandwidth. By disposing coil structures44within sensor cavity84below first conductive traces78, coil structures44are disposed within device10but outside (external to) antenna volume86. In other words, antenna currents may flow along patch element66(e.g., as shown by arrow96) without crossing the plane of coil structures44. This may prevent coil structures44from interfering with the transmission and/or reception of radio-frequency signals by antenna40while coil structures44receive wireless charging signals and/or while coil structures44are inactive, thereby maximizing the wireless performance of antenna40. This may also help to prevent antenna40from interfering with the reception of wireless charging signals by coil structures44, thereby maximizing wireless charging performance. By disposing antenna40at rear housing wall12R in this way, the vertical height of device10(e.g., parallel to the Z-axis ofFIG.4) may be shorter than would otherwise be possible in scenarios where the corresponding antenna resonating element is located elsewhere on device10(while still allowing antenna40to exhibit satisfactory antenna efficiency).

In practice, the wireless performance of antenna40may be optimized by the presence of an external object adjacent to rear housing wall12R. For example, the presence of the user's wrist102adjacent to rear housing wall12R when the user is wearing device10may enhance the wireless performance of antenna40. During operation, antenna40may transmit and/or receive radio-frequency signals having electric fields (E) that are oriented normal to the surfaces of rear housing wall12R and wrist102. These signals may sometimes be referred to as surface waves, which are then propagated along the surface of wrist102and outwards, as shown by paths104(e.g., patch element60and wrist102may serve as an electromagnetic waveguide that directs the surface waves outwards). This may allow the radio-frequency signals conveyed by antenna40to be properly received by external communications equipment (e.g., a wireless access point or base station) even though antenna40is located close to wrist102and typically pointed away from the external communications equipment.

FIG.6is a top-down view of patch element66in antenna40ofFIG.5(e.g., as viewed in the direction of arrow108ofFIG.5). The other portions of device10have been omitted fromFIG.6for the sake of clarity. As shown inFIG.6, patch element66may include first conductive traces78on first dielectric wall80(FIG.5), second conductive traces90on the underlying sensor board88, and conductive interconnect structure92that couples first conductive traces78to second conductive traces90. Central axis98may extend through second conductive traces90.

First conductive traces78may have an outer edge. First conductive traces78may also have an inner edge112opposite the outer edge. Second conductive traces90may have an (outer) edge110. First conductive traces78may laterally extend along a loop-shaped path extending around a central axis98(e.g., parallel to the Z-axis) and around second conductive traces90. Positive antenna terminal58may be coupled to first conductive traces78(e.g., at the outer edge of conductive traces78). Inner edge112of first conductive traces78may be laterally separated from edge110of second conductive traces90(as shown in the example ofFIG.6) or, if desired, first conductive traces78may at least partially overlap second conductive traces90(e.g., inner edge112of first conductive traces78may overlap second conductive traces90and/or edge110of second conductive traces90may overlap first conductive traces78). Conductive interconnect structure92may configure first conductive traces78, second conductive traces90, and the conductive interconnect structure to electrically form a single integrated patch element66for antenna40.

The example ofFIG.6is merely illustrative. The edges of conductive traces78and90may have other shapes (e.g., having any desired number of curved and/or straight segments). The shapes of conductive traces78and90may, for example, conform to the lateral shape of device10. If desired, additional conductive interconnect structures92may be disposed at other locations around central axis98to couple inner edge112of first conductive traces78to edge110of second conductive traces90at more than one point.

FIG.7is a plot of antenna performance (antenna efficiency) as a function of frequency showing how antenna40ofFIGS.2-6may exhibit improved wireless performance relative to scenarios where coil structures44are mounted within antenna volume86of antenna40(FIG.5). Curve114ofFIG.7plots the antenna efficiency of antenna40in implementations where coil structures44are mounted within antenna volume86of antenna40(e.g., in implementations where coil structures44are not disposed within sensor cavity84and laterally surrounding sensor board44). As shown by curve114, the antenna exhibits relatively low antenna efficiency within a frequency band between frequencies F1 and F2 in these implementations.

Curve116ofFIG.7plots the antenna efficiency of antenna40as shown inFIG.5. As shown by curve116, antenna40exhibits substantially higher efficiency in these implementations. Moving coil structures44out of antenna volume86and/or distributing patch element60between conductive traces78and90(e.g., as shown inFIGS.5and6) may serve to maximize the antenna efficiency between frequencies F1 and F2. Frequency F1 may be, for example, 500 MHz whereas frequency F2 is 3000 MHz. This may, for example, allow antenna40to cover the cellular LB and the cellular HB (as well as any bands between frequencies F1 and F2) with satisfactory levels of performance. The example ofFIG.7is merely illustrative. Curves114and116may have other shapes in practice and frequencies F1 and F2 may be any desired frequencies.