PATENT DOCUMENT

Publication Number: US-10224602-B2
Application Number: US-201514693274-A
Country: US
Kind Code: B2

Title: Electronic device with housing slots for antennas

Abstract:
An electronic device housing may have a rear housing wall that forms a metal ground plane. A slot may be formed in the metal ground plane. The slot may have one or more open ends along an edge of the ground plane. A near-field communications loop antenna may overlap the slot. The near-field communications loop antenna may have one or more turns. A current path through the metal ground plane may form one of the turns in the near-field communications loop antenna. The slot may form portions of non-near-field-communications antennas in addition to the near-field communications loop antenna. The slot in the non-near-field-communications antennas may be fed using an indirect antenna feed structure. Components such as a capacitor and inductor may help allow non-near-field communications antenna and the near-field communications antenna to be formed from common portions of the metal ground plane.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a housing having a metal rear wall that forms a ground plane; 
 a slot in the ground plane, wherein the slot is divided into first and second portions by a conductive structure that bridges the slot and wherein the first and second portions form respective first and second slot antenna resonating elements for indirectly fed non-near-field communications antennas; and 
 a near-field communications loop antenna that overlaps the slot, wherein the near-field communications loop antenna has an antenna feed with a first terminal coupled to a first portion of the metal rear wall on one side of the slot and a second terminal coupled to a second portion of the metal rear wall on another side of the slot and wherein a current path for the near-field communications loop antenna is formed at least from a conductive path through the first and second portions of the metal rear wall. 
 
     
     
       2. The electronic device defined in  claim 1  wherein the near-field communications loop antenna has at least one turn that is formed from the current path. 
     
     
       3. The electronic device defined in  claim 1  wherein the slot has a U-shaped outline. 
     
     
       4. The electronic device defined in  claim 1  wherein the current path is formed on a first portion of the ground plane and around the first portion of the slot and an additional current path for the near-field communications loop antenna is formed on a second portion of the ground plane and around the second portion of the slot. 
     
     
       5. The electronic device defined in  claim 4  wherein the antenna feed of the near-field communications loop antenna is coupled to the current path and a second near-field communications antenna feed is coupled to the additional current path. 
     
     
       6. The electronic device defined in  claim 5  further comprising:
 a near-field-communications transceiver; 
 a coupler coupled to the near-field-communications transceiver; 
 a phase shifter; 
 a first signal path that couples the near-field-communications transceiver to the antenna feed of the near-field communications loop antenna through the coupler and the phase shifter; and 
 a second signal path that couples the near-field-communications transceiver to the second near-field communications antenna feed through the coupler. 
 
     
     
       7. An electronic device, comprising:
 a housing having a rear face that forms a metal ground plane, wherein the metal ground plane has an edge; 
 a slot in the metal ground plane, wherein the slot has at least one open end along the edge, a first slot portion of the slot extends from the open end into the metal ground plane to divide the metal ground plane into first and second portions on first and second respective sides of the first slot portion, and a second slot portion of the slot extends perpendicularly from the first slot portion; and 
 a near-field communications loop antenna having a plurality of turns, wherein one of the turns is formed from a current path around the second slot portion, along first and second sides of the first slot portion, and through the metal ground plane, and the current path begins at a connection point on the first side of the first slot portion and ends at an antenna feed terminal on the second side of the first slot portion. 
 
     
     
       8. The electronic device defined in  claim 7  wherein the slot has a U-shaped outline with an additional open end along the edge. 
     
     
       9. The electronic device defined in  claim 7  further comprising a display mounted on the housing. 
     
     
       10. The electronic device defined in  claim 1  wherein the conductive path is formed through the conductive structure.

Description:
BACKGROUND 
     This relates to electronic devices, and more particularly, to antennas for electronic devices with wireless communications circuitry. 
     Electronic devices such as portable computers and cellular telephones are often provided with wireless communications capabilities. For example, electronic devices may use long-range wireless communications circuitry such as cellular telephone circuitry to communicate using cellular telephone bands. Electronic devices may use short-range wireless communications circuitry such as wireless local area network communications circuitry to handle communications with nearby equipment. Electronic devices may also be provided with satellite navigation system receivers and other wireless circuitry such as near-field communications circuitry. Near-field communications schemes involve electromagnetically coupled communications over short distances, typically 20 cm or less. 
     To satisfy consumer demand for small form factor wireless devices, manufacturers are continually striving to implement wireless communications circuitry such as antenna components using compact structures. At the same time, there is a desire for wireless devices to cover a growing number of communications bands. For example, in addition to covering local area network bands, a satellite navigation system band, and/or cellular telephone bands, it may be desirable for a wireless device to handle near-field communications. 
     Because antennas have the potential to interfere with each other and with components in a wireless device, care must be taken when incorporating antennas into an electronic device. Moreover, care must be taken to ensure that the antennas and wireless circuitry in a device are able to exhibit satisfactory performance over a range of operating frequencies. 
     It would therefore be desirable to be able to provide improved wireless communications circuitry for wireless electronic devices. 
     SUMMARY 
     An electronic device may be provided with a housing. A portion of the housing such as a metal rear housing wall may be used in forming a ground plane. A slot may be formed in the ground plane. The ground plane may have an edge. The slot may have one or more open ends along the edge. 
     A near-field communications loop antenna may overlap the slot. The slot may disrupt eddy currents in the ground plane to enhance antenna performance for the near-field communications loop antenna and may allow near-field communications signals to pass through the rear of the electronic device. 
     The near-field communications loop antenna may have one or more turns. A current path through the ground plane may form one of the turns in the near-field communications loop antenna. The near-field communications loop antenna may have antenna feed terminals that are coupled to the ground plane on opposing sides of the slot. 
     The slot and ground plane may be used in forming non-near-field-communications antennas in addition to the near-field communications loop antenna. For example, the slots may form slot antenna resonating elements. The slot elements of the non-near-field communications antennas may be fed using indirect antenna feed structures such as planar inverted-F antenna feed structures. Components such as a capacitor and inductor may help the non-near-field communications antenna and the near-field communications antenna to operate using shared portions of the ground plane. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative electronic device in accordance with an embodiment. 
         FIG. 2  is a schematic diagram of illustrative circuitry in an electronic device in accordance with an embodiment. 
         FIG. 3  is a diagram of illustrative wireless circuitry in an electronic device in accordance with an embodiment. 
         FIG. 4  is an interior view of an illustrative electronic device with a housing slot and a near-field communications antenna that overlaps the slot in accordance with an embodiment. 
         FIG. 5  is an interior view of an illustrative electronic device with a rectangular dielectric window overlapped by a near-field communications antenna in accordance with an embodiment. 
         FIG. 6  is an interior view of an illustrative electronic device having a slot with a rectangular ring and a straight segment that is joined to the ring and having a near-field communications structure that overlaps the slot in accordance with an embodiment. 
         FIG. 7  is an interior view of an illustrative electronic device having a slot with a rectangular ring and a straight segment that is joined to the ring and having a near-field communications structure that overlaps the slot and is partly formed using portions of a conductive housing in accordance with an embodiment. 
         FIG. 8  is an interior view of an illustrative electronic device having a U-shaped slot that is overlapped by a near-field communications antenna in accordance with an embodiment. 
         FIG. 9  is a perspective view of an illustrative planar-inverted-F antenna resonating element that may be used to indirectly feed a slot antenna in accordance with an embodiment. 
         FIG. 10  is an interior view of an illustrative electronic device having a pair of antennas formed from slots in a conductive housing and having a near-field communications antenna that is formed using the conductive housing in accordance with an embodiment. 
         FIG. 11  is an interior view of an illustrative electronic device in which a near-field communications antenna has been formed from two portions of a conductive housing that are driven out-of-phase in accordance with an embodiment. 
         FIG. 12  is an interior view of an illustrative electronic device having a slot bridged by a capacitor that forms a short circuit during high frequency antenna operation associated with non-near-field-communications antenna operation and that forms an open circuit at frequencies associated with use of a near-field communications antenna in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     An electronic device such as electronic device  10  of  FIG. 1  may be provided with wireless circuitry that includes antenna structures. The antenna structures may include a near-field communications antenna. The electronic device may have ground plane structures such as conductive housing structures that are configured to facilitate near-field communications using the near-field communications antenna by blocking eddy currents and by permitting near-field communications signals to pass through the rear of the electronic device. The ground plane structures such as the conductive housing structures may also form portions of the near-field communications antenna (e.g., by forming a current path that serves as one of the turns in a near-field communications loop antenna). In some configurations, the ground plane structures may be shared with non-near-field-communications antennas. For example, the ground plane structures such as the conductive housing structures may be used in forming antennas for cellular telephone communications and/or other far-field (non-near-field) communications in addition to forming a current path for a near-field communications loop antenna. 
     The wireless circuitry of device  10  may handles one or more communications bands. For example, the wireless circuitry of device  10  may include a Global Position System (GPS) receiver that handles GPS satellite navigation system signals at 1575 MHz or a GLONASS receiver that handles GLONASS signals at 1609 MHz. Device  10  may also contain wireless communications circuitry that operates in communications bands such as cellular telephone bands and wireless circuitry that operates in communications bands such as the 2.4 GHz Bluetooth® band and the 2.4 GHz and 5 GHz WiFi® wireless local area network bands (sometimes referred to as IEEE 802.11 bands or wireless local area network communications bands). Device  10  may also contain wireless communications circuitry for implementing near-field communications at 13.56 MHz or other near-field communications frequencies. If desired, device  10  may include wireless communications circuitry for communicating at 60 GHz, circuitry for supporting light-based wireless communications, or other wireless communications. 
     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 wrist-watch 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 cellular telephone, media player, tablet computer, or other portable computing device. 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  has been 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.). 
     Display  14  may be a touch screen display that incorporates a layer of conductive capacitive touch sensor electrodes or other touch sensor components (e.g., resistive touch sensor components, acoustic touch sensor components, force-based touch sensor components, light-based touch sensor components, etc.) or may be a display that is not touch-sensitive. Capacitive touch screen electrodes may be formed from an array of indium tin oxide pads or other transparent conductive structures. 
     Display  14  may include an array of display pixels formed from liquid crystal display (LCD) components, an array of electrophoretic display pixels, an array of plasma display pixels, an array of organic light-emitting diode display pixels, an array of electrowetting display pixels, or display pixels based on other display technologies. 
     Display  14  may be protected using a display cover layer such as a layer of transparent glass or clear plastic. Openings may be formed in the display cover layer. For example, an opening may be formed in the display cover layer to accommodate a button such as button  16 . An opening may also be formed in the display cover layer to accommodate ports such as a speaker port. Openings may be formed in housing  12  to form communications ports (e.g., an audio jack port, a digital data port, etc.). Openings in housing  12  may also be formed for audio components such as a speaker and/or a microphone. 
     Antennas may be mounted in housing  12 . For example, housing  12  may have four peripheral edges as shown in  FIG. 1  and one or more antennas may be located along one or more of these edges. As shown in the illustrative configuration of  FIG. 1 , antennas may, if desired, be mounted in regions  20  along opposing peripheral edges of housing  12  (as an example). Antennas may also be mounted in other portions of device  10 , if desired. The configuration of  FIG. 1  is merely illustrative. 
     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 such as storage and processing circuitry  28 . Storage and processing circuitry  28  may include storage such as 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. Processing circuitry in storage and processing circuitry  28  may be used to control the operation of device  10 . This processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, application specific integrated circuits, etc. 
     Storage and processing circuitry  28  may be used to run software on device  10 , such as 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, storage and processing circuitry  28  may be used in implementing communications protocols. Communications protocols that may be implemented using storage and processing circuitry  28  include internet protocols, wireless local area network protocols (e.g., IEEE 802.11 protocols—sometimes referred to as WiFi®), protocols for other short-range wireless communications links such as the Bluetooth® protocol, cellular telephone protocols, near-field communications protocols, MIMO protocols, antenna diversity protocols, etc. 
     Input-output circuitry  44  may include input-output devices  32 . Input-output devices  32  may be used to allow data to be supplied to device  10  and to allow data to be provided from device  10  to external devices. Input-output devices  32  may include user interface devices, data port devices, and other input-output components. For example, input-output devices may include touch screens, displays without touch sensor capabilities, buttons, joysticks, scrolling wheels, touch pads, key pads, keyboards, microphones, cameras, buttons, speakers, status indicators, light sources, audio jacks and other audio port components, digital data port devices, light sensors, motion sensors (accelerometers), capacitance sensors, proximity sensors, etc. 
     Input-output circuitry  44  may include wireless communications circuitry  34  for communicating wirelessly with external equipment. Wireless communications 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, transmission lines, and other circuitry for handling RF wireless signals. Wireless signals can also be sent using light (e.g., using infrared communications). 
     Wireless communications circuitry  34  may include radio-frequency transceiver circuitry  90  for handling various radio-frequency communications bands. For example, circuitry  34  may include transceiver circuitry  36 ,  38 , and  42 . Transceiver circuitry  36  may be wireless local area network transceiver circuitry that may handle 2.4 GHz and 5 GHz bands for WiFi® (IEEE 802.11) communications and that may handle the 2.4 GHz Bluetooth® communications band. Circuitry  34  may use cellular telephone transceiver circuitry  38  for handling wireless communications in frequency ranges such as a low communications band from 700 to 960 MHz, a midband from 1710 to 2170 MHz, and a high band from 2300 to 2700 MHz or other communications bands between 700 MHz and 2700 MHz or other suitable frequencies (as examples). Circuitry  38  may handle voice data and non-voice data. Wireless communications circuitry  34  may include satellite navigation system circuitry such as global positioning system (GPS) receiver circuitry  42  for receiving GPS signals at 1575 MHz or for handling other satellite positioning data. Wireless communications circuitry  34  can include circuitry for other short-range and long-range wireless links if desired. For example, wireless communications circuitry  34  may include 60 GHz transceiver circuitry, circuitry for receiving television and radio signals, paging system transceivers, etc. In WiFi® and Bluetooth® links and other short-range wireless links, wireless signals are typically used to convey data over tens or hundreds of feet. In cellular telephone links and other long-range links, wireless signals are typically used to convey data over thousands of feet or miles. 
     In addition to non-near-field communications circuitry such as circuitry  90 , wireless circuitry  34  may include near-field communications circuitry  120 . Near-field communications circuitry  120  may produce and receive near-field communications signals to support communications between device  10  and a near-field communications reader or other external near-field communications equipment. Near-field communications may be supported using loop antennas (e.g., to support inductive near-field communications in which a loop antenna in device  10  is electromagnetically near-field coupled to a corresponding loop antenna in a near-field communications reader). Near-field communications links are generally formed over distances of 20 cm or less (i.e., device  10  must be placed in the vicinity of the near-field communications reader for effective communications). 
     Wireless communications 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 loop antenna structures, patch antenna structures, inverted-F antenna structures, slot antenna structures, planar inverted-F antenna structures, helical antenna structures, hybrids of these designs, etc. 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 and another type of antenna may be used in forming a remote wireless link antenna. In addition to supporting cellular telephone communications, wireless local area network communications, and other far-field wireless communications, the structures of antennas  40  may be used in supporting near-field communications for near-field communications transceiver  120 . The structures of antennas  40  may also be used in gathering proximity sensor signals (e.g., capacitive proximity sensor signals), if desired. 
     Radio-frequency transceiver circuitry  90  does not handle near-field communications signals and is therefore sometimes referred to as far field communications circuitry or non-near-field communications circuitry. Transceiver circuitry  90  may handle non-near-field communications frequencies such as frequencies above 700 MHz or other suitable frequencies. Near-field communications transceiver circuitry  120  may be used in handling near-field communications. With one suitable arrangement, near-field communications can be supported using signals at a frequency of 13.56 MHz. Other near-field communications bands may be supported using the structures of antennas  40  if desired. 
     As shown in  FIG. 3 , non-near-field transceiver circuitry  90  in wireless circuitry  34  may be coupled to antenna structures  40  using paths such as path  92 . Near-field communications transceiver circuitry  120  may be coupled to antenna structures  40  using paths such as path  132 . Paths such as path  134  may be used to allow control circuitry  28  to transmit near-field communications data and to receive near-field communications data using transceiver  120  and a near-field communications antenna formed from structures  40 . 
     Control circuitry  28  may be coupled to input-output devices  32 . Input-output devices  32  may supply output from device  10  and may receive input from sources that are external to device  10 . 
     To provide antenna structures  40  with the ability to cover communications frequencies of interest, antenna structures  40  may be provided with impedance matching circuitry, filters, and other antenna circuitry. This circuitry may include fixed and tunable circuits. Discrete components such as capacitors, inductors, and resistors may be incorporated into the antenna 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 structures  40  may be provided with adjustable circuits such as tunable components  102  to tune antennas over communications bands of interest. Tunable components  102  may include tunable inductors, tunable capacitors, or other tunable components. Tunable components such as these may be based on switches and networks of fixed components, distributed metal structures that produce associated distributed capacitances and inductances, variable solid state devices for producing variable capacitance and inductance values, tunable filters, or other suitable tunable structures. For example, tunable components  102  may include one or more adjustable capacitors (e.g., a programmable capacitor that can produce one of multiple different capacitance values by adjusting switching circuitry), one or more adjustable inductors (e.g., an adjustable inductor circuit having a multiplexer or other adjustable switching circuitry that allows a desired inductor value to be selected from multiple different available inductor values), or other adjustable components. 
     During operation of device  10 , control circuitry  28  may issue control signals on one or more paths such as path  103  that adjust inductance values, capacitance values, or other parameters associated with tunable components  102 , thereby tuning antenna structures  40  to cover desired communications bands. Active and/or passive components may also be used to allow antenna structures  40  to be shared between non-near-field-communications transceiver circuitry  90  and near-field communications transceiver circuitry  120  and/or separate antenna structures may be used in forming non-near-field communications antennas and near-field communications antennas. 
     Path  92  may include one or more transmission lines. As an example, signal path  92  of  FIG. 2  may be a transmission line having a positive signal conductor such as line  94  and a ground signal conductor such as line  96 . Lines  94  and  96  may form parts of a coaxial cable or a microstrip transmission line (as examples). A matching network formed from components such as inductors, resistors, and capacitors may be used in matching the impedance of antenna structures  40  to the impedance of transmission line  92 . 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 and other antenna circuitry in antenna structures  40 . 
     Transmission line  92  may be directly coupled to an antenna resonating element and ground for antenna  40  or may be coupled to indirect-feed antenna feed structures that are used in indirectly feeding a resonating element for antenna  40 . As an example, antenna structures  40  may form an inverted-F antenna, a slot antenna, a hybrid inverted-F slot antenna or other antenna having an antenna feed with a positive antenna feed terminal such as terminal  98  and a ground antenna feed terminal such as ground antenna feed terminal  100 . Positive transmission line conductor  94  may be coupled to positive antenna feed terminal  98  and ground transmission line conductor  96  may be coupled to ground antenna feed terminal  92 . Antenna structures  40  may include an antenna resonating element such as a slot antenna resonating element or other element that is indirectly fed. In indirect feeding arrangements, transmission line  92  is coupled to an antenna feed structure that is used to indirectly feed antenna structures such as an antenna slot or other element through electromagnetic near-field coupling. 
     Antennas  40  may include slot antenna structures, inverted-F antenna structures (e.g., planar and non-planar inverted-F antenna structures), loop antenna structures, or other antenna structures. 
     Device  10  may include a ground plane that serves as antenna ground in a slot antenna, an inverted-F antenna, or other suitable antenna(s). The ground plane may be formed from metal traces on a printed circuit or other substrate, conductive components in device  10  (e.g., components containing metal), and/or conductive housing structures (e.g., housing  12  or parts of housing  12  may be formed from metal and may be used in forming an antenna ground). An illustrative ground plane (sometimes referred to as ground or antenna ground) is shown in  FIG. 4 . As shown in  FIG. 4 , ground plane  140  may have a rectangular shape (e.g., a rectangular shape with four edges that run parallel to each of the four edges of device  10  of  FIG. 1 ). 
     Ground plane  140  may be formed from a metal housing (e.g. the rear wall and sidewalls of housing  12  of  FIG. 1 ), may be formed from metal traces on one or more printed circuits, may be formed from conductive electronic components (e.g., metal shield cans, etc.), and/or may be formed from other conductive structures in device  10 . If desired, multiple ground structures may overlap one another within device  10 . Configurations in which ground  140  includes the rear metal housing wall of housing  12  are sometimes described herein as an example. Device  10  may have conductive housing sidewalls that extend upwards from the rear metal housing wall (e.g., as curved or straight extensions of the rear housing wall), may have a display bezel or peripheral housing band that is formed from a separate metal member that is shorted to the rear housing wall or may, in some scenarios, be formed form a non-conductive material such as plastic. 
     In scenarios in which the sidewalls or portions of the sidewalls of housing  12  are formed from dielectric, the ground plane for device  10  can be formed from the metal rear housing wall (and/or internal conductive structures). In scenarios in which the sidewalls or portions of the sidewalls are formed from a conductive material such as metal, these sidewall structures may form part of the ground plane for device  10 . Ground plane  140  may have a flat shape (i.e., a planar shape associated with the rear face of device  10  which may or may not include short vertically extending sidewall portions), may have a curved shape (e.g., when device  10  has a convex or concave rear face), or may have other suitable shapes. 
     In configurations in which ground  140  is formed from a portion of a conductive housing such as metal housing  12 , it may be desirable to form one or more openings in the metal of the housing. The openings may have elongated shapes and may therefore sometimes be referred to as slots. The slots may be straight slots (i.e., slots without bends when viewing housing  12  from above), may be L-shaped slots (slots with one bend), may be U-shaped slots (slots with two bends), or may have other suitable shapes. 
     Plastic, glass, ceramic, or other dielectric materials may fill the openings in the metal housing. As shown in  FIG. 4 , for example, ground plane  140  may have a slot such as slot  142  that runs inwardly toward the center of housing  12  from upper housing edge  12 E. This slot (and the other illustrative slots in ground  14 ) may be filled with plastic or other dielectric. 
     In configurations for device  10  in which housing  12  has metal sidewalls that extend upwardly from the rear face of housing  12 , slots such as slot  142  of  FIG. 4  may extend through the metal sidewalls (i.e., edge  12 E may be associated with the upper surface of the metal sidewalls where the metal sidewalls meet the display cover layer of display  14  or other display structures). In configurations for device  10  in which housing  12  has dielectric sidewalls and a metal rear housing wall, edge  12 E may be associated with the periphery of the metal rear wall. 
     In the example of  FIG. 4 , slot  142  has a straight outline (when viewed from above as in  FIG. 4 ) with opposing ends  142 - 1  and  142 - 2 . Slot end  142 - 1  may be open to the air surrounding device  10  and/or a dielectric display cover layer and may therefore be referred to as an open end of slot  142 . Slot end  142 - 2  may be surrounded by portions of ground  140  and may therefore be referred to as a closed end of slot  142 . Slots of the type shown in  FIG. 4  that have opposing open and closed ends are sometimes referred to as open slots. If desired, housing  12  may contain closed slots (i.e., slots with two opposing closed ends). 
     Near-field communications antenna  144  may be formed in device  10  in a location that overlaps slot  142  (i.e., a location where the footprint of antenna  144  covers some or all of slot  142 ). Antenna  144  may be a loop antenna. and may contain one or more loops of conductor (e.g., one or more loops of wire, one or more loops of metal traces on a printed circuit, or other suitable conductive loops). In the example of  FIG. 4 , antenna  144  has two loop-shaped conductive paths  146  (i.e., antenna  144  has two turns formed from conductive paths  146 ). In general, antenna  144  may be a loop antenna with 5-50 turns, 20-25 turns, more than 20 turns, fewer than 25 turns, more than 2 turns, fewer than 30 turns, or any other suitable number of turns. The outline of the loop of antenna  144  (i.e., the footprint of antenna  144  when viewed from above as shown in  FIG. 4 ) preferably overlaps at least some of slot  142 . In the example of  FIG. 4 , slot  142  is sufficiently long to bisect antenna  144 . 
     The presence of slot  142  helps antenna  144  operate satisfactorily within conductive housing  12 . In particular, the presence of slot  142  may disrupt eddy currents that might otherwise develop within housing  12  under antenna  144 . This disruption of eddy currents helps improve antenna efficiency when antenna  144  is operated in the upwards direction (i.e., out of the page of  FIG. 4  and through a portion of the front face of device  10  such as through inactive edge portions of display  14 ). When operated in the opposite direction (i.e., into the page of  FIG. 4  and out of the rear face of device  10 ), the dielectric opening formed by slot  142  may allow near-field communications electromagnetic signals to exit device  10  through the rear housing wall. These signals might otherwise be blocked by the metal of the rear housing wall if antenna  144  were completely covered with the metal of the rear housing wall. The size of slot  142  may be larger to enhance near-field communications antenna efficiency or the size of slot  142  may be smaller to enhance device aesthetics. With one suitable arrangement, the width of slot  142  may be less than 5 mm, less than 3 mm, less than 2 mm, less than 1 mm, greater than 0.1 mm, 0.1-2 mm, 0.1-0.7 mm, or other suitable size. 
     Antenna  144  has an antenna feed formed from positive antenna feed terminal  148  and ground antenna feed terminal  150 . The antenna feed for antenna  144  may be coupled to near-field communications transceiver  120  ( FIG. 3 ) by signal lines in path  132  to allow antenna  144  to transmit and receive near-field communications signals. 
     In the illustrative configuration of  FIG. 5 , dielectric opening  142  has a shape that matches the outline of near-field communications antenna  144  (i.e., the size of opening  142  matches the size of antenna  144 ). In particular, opening  142  may have a main rectangular window portion such as portion  142 R to allow near-field communications signals to pass through the rear wall of device  10 . Opening  142  may also have a segment such as segment  142 ′ that extends from opening  142 R to upper housing edge  12 E to help block eddy currents that might be induced in housing  12  during operation of antenna  144 . 
     Dielectric-filled opening  142  of  FIG. 5  may consume more area than desired. An arrangement for opening  142  that consumes a relatively small amount of area and which is therefore less visible when viewing the rear of device  10  is shown in  FIG. 6 . In the example of  FIG. 6 , dielectric opening  142  in housing  12  has a ring portion (rectangular ring  142 RR) that is joined to segment  142 ′. Central portion  12 H of metal housing  12 , which forms an inner portion of ground plane  140 , may be surrounded by rectangular ring  142 RR. As with the configuration of  FIG. 4 , the configuration of  FIG. 6  may help block eddy currents (and thereby enhance operation of antenna  144  out of the front of device  10  and may create a dielectric gap that allows antenna  144  to operate out of the rear of device  10 . Openings  142  such as illustrative ring  142 RR of  FIG. 5  may have curved segments, straight segments, combinations of curved and straight segments, or other suitable shapes. The configuration of  FIG. 6  in which ring  142 RR has a rectangular outline surrounding a rectangular metal portion  12 H of housing  12  is merely illustrative. 
     If desired, a portion or all of loop antenna  144  may be formed using current paths that pass through conductive housing structures such as portions of a rear wall (and, if desired, sidewall portions) in metal housing  12 . This type of configuration is shown in  FIG. 7 . As shown in  FIG. 7 , opening  142  in housing  12  may have a slot that forms rectangular ring  142 RR and slot segment  142 ′, as described in connection with  FIG. 6 . Some of the turns of loop antenna  144  may be formed by conductive paths  146  (e.g., metal traces on a printed circuit, turns of wire, etc.). In the example of  FIG. 7 , an additional turn of loop antenna  144  has been formed by conductive path  146 ′ through metal housing  12 . Path  146 ′ starts at node  152 , where the conductor of one of paths  146  is shorted to metal housing  12  and continues around the periphery of opening  142 RR to ground terminal  150  on metal housing  12 . 
     In the illustrative configuration of  FIG. 8 , the turns of loop antenna  144  include conductive paths  146  (e.g., wires, traces on a printed circuit, etc.) and conductive housing path  146 ′. Antenna  144  overlaps slot  142 . Slot  142  has a U-shape with a pair of opposing open ends  142 - 1  in edge  12 E of housing  12 . The presence of slot  142  may help disrupt eddy currents that might otherwise adversely affect antenna performance and may allow near-field communications antenna signals to be transmitted and received through the rear of housing  12 . The width of slot  142  may be about 0.1-0.9 mm, may be less than 1.5 mm, may be more than 0.1 mm, or may have other suitable sizes. Lateral dimension D 2  of antenna  144  may be about 15-28 mm, more than 10 mm, less than 35 mm, or other suitable sizes. Perpendicular lateral dimension D 1  of antenna  144  may be about 8-14 mm, more than 5 mm, less than 25 mm, or other suitable size. 
     Near-field communications loop antenna  144  may, if desired, be formed using housing structures that form a common ground (ground  140 ) with non-near-field communications antennas (e.g., wireless local area network antennas, satellite navigation system antennas, cellular telephone antennas, other antennas that operate at frequencies of 700 MHz to 5 GHz, etc.). Non-near-field antennas in device  10  may be fed using a direct feeding arrangement or an indirect feeding arrangement. As an example, device  10  may contain an antenna that includes a slot antenna resonating element. The slot antenna resonating element may be formed from some or all of slot  142  in ground  140  (e.g., portions of metal housing  12  such as a rear housing wall). The slot antenna resonating element may form a slot antenna or may form a slot portion of a hybrid antenna such as a planar-inverted-F-slot antenna or an inverted-F-slot antenna. 
     With a direct feeding arrangement, the slot antenna resonating element formed from slot  142  may be fed using terminals that are coupled to ground  140  on opposing sides of the slot. With an indirect feeding arrangement, an antenna feed structure such as illustrative planar-inverted-F element  154  of  FIG. 9  may serve as an indirect antenna feed structure for the antenna. Element  154  may be near-field coupled to the slot antenna resonating element formed from slot  142 . 
     Element  154  may have a planar resonating element portion such as planar member  156  that overlaps slot  142 . Return path  158  may be shorted between member  156  and ground  140 . Feed  160  may be coupled between member  156  and ground  140  in parallel with return path  158 . Feed  160  may include positive antenna feed terminal  98  and ground antenna feed terminal  100 . If desired, other arrangements may be used to feed the slot antenna resonating element formed from slot  142 . Planar-inverted-F feed structure  154  of  FIG. 9  is merely illustrative. 
     An interior view of a portion of electronic device  10  in an illustrative configuration in which there are two independently fed antennas formed from left and right branches of slot  142  are is shown in  FIG. 10 . As shown in  FIG. 10 , slot  142  in ground  140  (i.e., metal housing  12 ) has left segment  142 L and right segment  142 R, each with an open end  142 - 1  along edge  12 E. Conductive structure  164  (e.g., metal traces in a printed circuit, metal foil, a metal member formed from a sheet of metal, a portion of housing  12 , or other conductive structures) may bridge the middle of slot  142  and thereby short housing  12  on opposing sides of slot  142 . The presence of conductive structure  164  bisects slot  142  into left and right portions  142 L and  142 R and may form closed slot ends for the resulting left and right slots formed from slot  142 . 
     Left slot  142 L may form a slot antenna resonating element for non-near-field communications antenna  162 L. Antenna  162 L may be indirectly fed using indirect antenna feed structure  154 L (i.e., a structure with planar portion  156 L, return path  158 L, and feed  160 L, as described in connection with  FIG. 9 ). Right slot  142 R may form a slot antenna resonating element for non-near-field communications antenna  162 R. Antenna  162 R may be indirectly fed using indirect antenna feed structure  154 R (i.e., a structure with planar portion  156 R, return path  158 R, and feed  160 R, as described in connection with  FIG. 9 ). Antennas  162 L and  162 R may be wireless local area network antennas, satellite navigation system antennas, cellular telephone antennas, or other antennas for supporting non-near-field communications. 
     Near-field communications loop antenna  144  has feed terminals  148  and  150 . Terminal  148  is shorted to housing portion  12 H of ground  140 . Terminal  150  is shorted to housing portion  12 ′ of housing  12 . Near-field communications loop antenna  144  is formed from a loop-shaped conductive path (path  146 ′) that forms a turn in loop antenna  144  that passes from terminal  148  to terminal  150  through the metal of housing portion  12 H, the metal of conductive structure  164 , and the metal of housing  12 ′, as shown in  FIG. 10 . With this type of arrangement, antenna  144  is formed at least partly from the same ground plane  140  that is used in forming a non-near-field antenna in device  10 . 
     In the arrangement of  FIG. 11 , current loops  146 ′ are formed in portions of ground plane  140  associated with both left antenna  162 L and right antenna  162 R. Current loop  146 ′- 1 , passes through the portion of ground plane  140  associated with antenna  162 L and carries current I 1 . Current loop  146 ′- 2  passes through the portion of ground plane  140  associated with antenna  162 R and carries current I 2 . Current loop path  146 ′- 1  and current loop path  146 ′- 2  form first and second respective portions  144 - 1  and  144 - 2  of near-field communications antenna  144 . 
     Near-field communications transceiver  120  may be coupled to terminals  148 - 1  and  150 - 1  at the feed of antenna portion  144 - 1  through coupler  170 , phase shifter  172  (e.g., a 180° phase shifter), and path  132 - 1 . Near-field communications transceiver  120  may be coupled to terminals  148 - 2  and  150 - 2  at the feed of antenna portion  144 - 2  through coupler  170  and path  132 - 2 . In the absence of phase shifter  172 , current I 1  will induce a magnetic field B 1  that is oriented into the page of  FIG. 11  (as indicated by field  174 ) at the same time that current I 2  induces a magnetic field B 2  that is oriented out of the page (as indicate by field  176 ). By virtue of phase shifter  172 , the out-of-phase version of magnetic field B 1  is converted to in-phase magnetic field B 1 ′. As indicated by the parallel direction of field  178  of B 1 ′ and field  176  of B 2 , the use of phase shifter  172  ensures that the near-field signals produced by near-field communications antenna portions  144 - 1  and  144 - 2  will add constructively, thereby allowing portions  144 - 1  and  144 - 2  to form near-field communications loop antenna  144 . 
     If desired, a component such as capacitor  180  of  FIG. 12  may be used to bridge slot  142  in the middle of slot  142 . Inductor  182  may have a first terminal (terminal  184 ) coupled to housing portion  12 H on one side of slot  142  and a second terminal (terminal  186 ) coupled to housing portion  12 ″ on the other side of slot  142 . At near-field communications frequencies (e.g., 13.56 MHz), inductor  182  is a short circuit. As a result, current loop  146 ′ for near-field communications loop antenna  144  may be established between antenna feed terminal  148  on housing portion  12 H and antenna feed terminal  150 . The path of current loop  146 ′ may be formed using a segment of housing  12 H, inductor  182 , and the portion of housing  12  that runs along the lower edge of slot  142  and back to antenna feed terminal  150 . At near-field communications frequencies, capacitor  180  is an open circuit, so current  146 ′ will not be diverted across the middle of slot  142  and will flow in a loop that surrounds slot  142 . At non-near-field communications frequencies (e.g., frequencies above 13.56 MHz such as frequencies at 700 MHz and above), capacitor  180  is a short circuit and inductor  182  is an open circuit. The short circuit of capacitor  180  divides slot  142  into left and right portions for non-near-field-communications antennas  162 L and  162 R. The open circuit of inductor  182  ensures that slot  142  will have two open ends  142 - 1  along edge  12 E. The middle of slot  142  will be a short circuit (and therefore will form closed ends for the left and right portions of the slot) at non-near-field-communications frequencies. 
     The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20150422
Publication Date: 20190305
Grant Date: 20190305
Priority Date: 20150422
Inventors: AZAD, Umar
RAJAGOPALAN, HARISH
PASCOLINI, MATTIA
GOMEZ ANGULO, RODNEY A.
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q1/243", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q7/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/48", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q13/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q13/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q13/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q7/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/48", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q7/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/48", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 57148177