PATENT DOCUMENT

Publication Number: US-10193597-B1
Application Number: US-201815900407-A
Country: US
Kind Code: B1

Title: Electronic device having slots for handling near-field communications and non-near-field communications

Abstract:
An electronic device may be provided with a conductive wall. A gap in the wall may divide the wall into first and second segments. A ground may be separated from the wall by first, second, and third slots that form radiating elements for first, second, and third non-near-field communications antennas. First and second conductive structures may be coupled between the wall and the ground. A near-field communications antenna may include a first feed terminal coupled to the first segment and a second feed terminal coupled to the second segment. The antenna may convey signals over a conductive loop path that includes portions of the first and second segments, the antenna ground, and the first and second conductive structures. A differential or single-ended signal transmission line may be coupled to the terminals. Phase shifters may configure the signals to be out of phase at the feed terminals.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a housing having a peripheral conductive wall; 
 a dielectric-filled gap in the peripheral conductive wall that divides the peripheral conductive wall into first and second segments; 
 an antenna ground separated from the peripheral conductive wall by a slot; 
 a non-near-field communications antenna having an antenna feed coupled between the first segment and the antenna ground across the slot; 
 a near-field communications antenna having a first antenna feed terminal coupled to the first segment and a second antenna feed terminal coupled to the second segment; 
 a transmission line coupled to the first and second antenna feed terminals; and 
 near-field communications transceiver circuitry coupled to the transmission line, wherein the near-field communications transceiver circuitry is configured to convey near-field communications signals using the near-field communications antenna. 
 
     
     
       2. The electronic device defined in  claim 1 , further comprising:
 non-near-field communications transceiver circuitry coupled to the antenna feed and configured to convey non-near-field communications signals using the non-near-field communications antenna. 
 
     
     
       3. The electronic device defined in  claim 2 , further comprising:
 an additional non-near-field communications antenna having an additional antenna feed coupled between the second segment and the antenna ground, wherein the non-near-field communications transceiver circuitry is coupled to the additional antenna feed and configured to convey the non-near-field communications signals using the additional non-near-field communications antenna. 
 
     
     
       4. The electronic device defined in  claim 3 , wherein the non-near-field communications transceiver circuitry is configured to concurrently convey the non-near-field communications signals over the non-near-field communications antenna and the additional non-near-field communications antenna at a given frequency using a multiple-input and multiple-output (MIMO) scheme. 
     
     
       5. The electronic device defined in  claim 4 , wherein the given frequency comprises a cellular telephone frequency between 600 MHz and 4000 MHz. 
     
     
       6. The electronic device defined in  claim 2 , further comprising:
 a first conductive structure coupled between the first segment and the antenna ground; and 
 a second conductive structure coupled between the second segment and the antenna ground, wherein the near-field communications antenna comprises a conductive loop path that includes a portion of the first segment, a portion of the second segment, the first conductive structure, a portion of the antenna ground extending between the first and second conductive structures, and the second conductive structure, the antenna feed being coupled to the portion of the first segment. 
 
     
     
       7. The electronic device defined in  claim 6 , further comprising:
 a capacitive circuit coupled between the portion of the second segment and the portion of the antenna ground, wherein the capacitive circuit is configured to form an open circuit at a frequency of the near-field communications signals and the capacitive circuit is configured to form a short circuit path between the portion of the second segment and the portion of the antenna ground at a frequency of the non-near-field communications signals. 
 
     
     
       8. The electronic device defined in  claim 1 , wherein the transmission line comprises a ground conductor coupled to the first antenna feed terminal and a signal conductor coupled to the second antenna feed terminal, the electronic device further comprising:
 an inductor interposed on the signal conductor. 
 
     
     
       9. The electronic device defined in  claim 1 , wherein the transmission line comprises a differential signal transmission line having a first conductor coupled to the first antenna feed terminal and a second conductor coupled to the second antenna feed terminal, the near-field communications signals comprising a first differential signal of a differential signal pair conveyed over the first conductor and a second differential signal of the differential signal pair conveyed over the second conductor. 
     
     
       10. The electronic device defined in  claim 9 , wherein the first differential signal at the first antenna feed terminal is out of phase with respect to the second differential signal at the second antenna feed terminal. 
     
     
       11. The electronic device defined in  claim 1 , further comprising:
 a balun that couples the near-field communications transceiver circuitry to the transmission line, wherein the transmission line comprises a first conductor coupled between a circuit node and the first antenna feed terminal, a second conductor coupled between the circuit node and the second antenna feed terminal, and a third conductor coupled between the circuit node and the balun; 
 a first phase shifter interposed on the first conductor; and 
 a second phase shifter interposed on the second conductor. 
 
     
     
       12. The electronic device defined in  claim 11 , wherein the first and second phase shifters are configured to apply phase shifts to the near-field communication signals that configure the near-field communications signals at the first antenna feed terminal to be out of phase with respect to the near-field communications signals at the second antenna feed terminal. 
     
     
       13. An electronic device comprising:
 a housing having peripheral conductive structures; 
 first, second, and third dielectric-filled gaps in the peripheral conductive structures, wherein a first segment of the peripheral conductive structures extends between the first and third dielectric-filled gaps and a second segment of the peripheral conductive structures extends between the third and second dielectric-filled gaps; 
 an antenna ground, wherein the first dielectric-filled gap separates the first segment from the antenna ground and the second dielectric-filled gap separates the second segment from the antenna ground; 
 a transmission line having a first conductor coupled to a first antenna feed terminal on the first segment and a second conductor coupled to a second antenna feed terminal on the second segment; and 
 near-field communications transceiver circuitry coupled to the transmission line and configured to convey near-field communications signals over a conductive loop path that extends from the first antenna feed terminal to the second antenna feed terminal and that includes a portion of the first segment, a portion of the second segment, and a portion of the antenna ground. 
 
     
     
       14. The electronic device defined in  claim 13 , further comprising:
 a first conductive structure coupled between the first segment and the antenna ground, wherein the portion of the first segment extends from the first conductive structure to the first antenna feed terminal and the conductive loop path includes the first conductive structure. 
 
     
     
       15. The electronic device defined in  claim 14 , further comprising:
 a second conductive structure coupled between the second segment and the antenna ground, wherein the portion of the second segment extends from the second antenna feed terminal to the second conductive structure, the portion of the antenna ground extends between the first and second conductive structures, and the conductive loop path includes the second conductive structure. 
 
     
     
       16. The electronic device defined in  claim 15 , further comprising:
 a camera module, wherein the camera module comprises the second conductive structure. 
 
     
     
       17. The electronic device defined in  claim 15 , further comprising:
 phase shifter circuitry configured to apply a phase shift to the near-field communications signals, wherein the phase shift configures the near-field communications signals at the first antenna feed terminal to be out of phase with respect to the near-field communications signals at the second antenna feed terminal. 
 
     
     
       18. The electronic device defined in  claim 15 , further comprising:
 an antenna feed coupled between the portion of the first segment and the portion of the antenna ground; 
 an additional transmission line coupled to the antenna feed; and 
 non-near-field communications transceiver circuitry coupled to the additional transmission line, wherein the non-near-field communications circuitry is configured to convey non-near-field communications signals at a higher frequency than the near-field communications signal using an antenna that includes the portion of the first segment, the first conductive structures, the portion of the antenna ground, and the antenna feed. 
 
     
     
       19. An electronic device comprising:
 conductive structures; 
 first, second, and third slots in the conductive structures, wherein a first portion of the conductive structures separates the first slot from the second slot and a second portion of the conductive structures separates the second slot from the third slot; 
 a first antenna feed for a first non-near-field communications antenna coupled across the first slot; 
 a second antenna feed for a second non-near-field communications antenna coupled across the second slot; 
 a third antenna feed for a third non-near-field communications antenna coupled across the third slot; 
 non-near-field communications transceiver circuitry coupled to the first, second, and third antenna feeds and configured to convey non-near-field signals using the first, second, and third non-near-field communications antennas; and 
 near-field communications transceiver circuitry coupled to first and second antenna feed terminals on the conductive structures, wherein the near-field communications transceiver circuitry is configured to convey near-field communications signals over a conductive loop path that extends around the second slot and includes the first and second portions of the conductive structures. 
 
     
     
       20. The electronic device defined in  claim 19 , wherein the second slot comprises an open slot having an open end and the first and second antenna feed terminals are coupled to the conductive structures at opposing sides of the open end of the open slot.

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, it may be desirable for a wireless device to cover a near-field communications band while simultaneously covering additional non-near-field (far-field) bands. 
     Because antennas have the potential to interfere with each other and with components in a wireless device, care must be taken when incorporating antennas into an electronic device. Moreover, care must be taken to ensure that the antennas and wireless circuitry in a device are able to exhibit satisfactory performance over a range of operating frequencies and with a satisfactory efficiency bandwidth. 
     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 wireless circuitry and a housing having a peripheral conductive wall. The wireless circuitry may include non-near-field communications antennas coupled to non-near-field communications transceiver circuitry. The non-near-field communications antennas may handle non-near-field communications signals such as cellular telephone signals. The wireless circuitry may include a near-field communications antenna coupled to near-field communications circuitry. The near-field communications antenna may handle near-field communications signals such as radio-frequency signals at 13.56 MHz. 
     A dielectric-filled gap in the peripheral conductive wall may divide the peripheral conductive wall into first and second segments. The wireless circuitry may include an antenna ground separated from the peripheral conductive wall by first, second, and third slots. A first conductive structure may be coupled between the first segment and the antenna ground and may separate the first slot from the second slot. A second conductive structure may be coupled between the second segment and the antenna ground and may separate the second slot from the third slot. The first, second, and third slots may form radiating elements for respective first, second, and third non-near-field communications antennas. The first, second, and third non-near-field communications antennas may each include antenna feeds that are coupled across the respective first, second, and third slots and that are coupled to the non-near-field communications circuitry. 
     The near-field communications antenna may be formed from a conductive loop path extending between first and second antenna feed terminals. The first antenna feed terminal may be coupled to the first segment adjacent to the dielectric-filled gap. The second antenna feed terminal may be coupled to the second segment adjacent to the dielectric-filled gap. The conductive loop path may include a portion of the second segment extending from the second antenna feed terminal to the second conductive structure, the second conductive structure, a portion of the antenna ground extending between the first and second conductive structures, the first conductive structure, and a portion of the first segment extending from the first conductive structure to the first antenna feed terminal. The first and second antenna feed terminals may be coupled to the near-field communications transceiver circuitry over a transmission line path. 
     The transmission line path may include a single-ended signal transmission line path having a ground conductor coupled to the first antenna feed terminal and a signal conductor coupled to the second antenna feed terminal. An inductor may be interposed on the signal conductor. In another suitable arrangement, the transmission line path may include a differential signal transmission line path having a first conductor coupled to the first antenna feed terminal and a second conductor coupled to the second antenna feed terminal. Phase shifter circuitry may be formed within the near-field communications transceiver circuitry or on the transmission line path. The phase shifter circuitry may apply one or more phase shifts to the near-field communications signals so that the near-field communications signals at the first antenna feed terminal are out of phase with respect to the near-field communications signals at the second antenna feed terminal. This may, for example, minimize magnetic field cancellation associated with the near-field communications signals at opposing sides of the dielectric-filled gap, thereby optimizing antenna efficiency for the near-field communications antenna. 
    
    
     
       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 schematic diagram of illustrative wireless communications circuitry in accordance with an embodiment. 
         FIG. 4  is a diagram of illustrative slot antenna structures in accordance with an embodiment. 
         FIG. 5  is a top view of an illustrative electronic device having a slot for performing both near-field communications and non-near-field communications in accordance with an embodiment. 
         FIG. 6  is a top view of an illustrative electronic device having a slot fed using differential antenna signals for performing near-field communications in accordance with an embodiment. 
         FIG. 7  is a diagram showing how phase shifter circuitry may be used to feed antenna signals for a slot of the type shown in  FIGS. 6 and 7  in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices such as electronic device  10  of  FIG. 1  may be provided with wireless communications circuitry. The wireless communications circuitry may be used to support wireless communications in multiple wireless communications bands. 
     The wireless communications circuitry may include antenna structures. The antenna structures may include antennas for cellular telephone communications and/or other far-field (non-near-field) communications. Circuitry in the antenna structures may allow the antenna structures to form a near-field communications loop antenna to handle near-field communications. The antenna structures may include loop antenna structures, inverted-F antenna structures, strip antenna structures, planar inverted-F antenna structures, slot antenna structures, hybrid antenna structures that include antenna structures of more than one type, or other suitable antenna structures. Conductive structures for the antenna structures may, if desired, be formed from conductive electronic device structures. 
     The conductive electronic device structures may include conductive housing structures. The housing structures may include peripheral structures such as peripheral conductive structures that run around the periphery of the electronic device. The peripheral conductive structures may serve as a bezel for a planar structure such as a display, may serve as sidewall structures for a device housing, may have portions that extend upwards from an integral planar rear housing (e.g., to form vertical planar sidewalls or curved sidewalls), and/or may form other housing structures. 
     Gaps may be formed in the peripheral conductive structures that divide the peripheral conductive structures into peripheral segments. One or more of the segments may be used in forming one or more antennas for electronic device  10 . Antennas may also be formed using an antenna ground plane and/or an antenna resonating element formed from conductive housing structures (e.g., internal and/or external structures, support plate structures, etc.). 
     Electronic device  10  may be a portable electronic device or other suitable electronic device. For example, electronic device  10  may be a laptop computer, a tablet computer, a somewhat smaller device such as a wrist-watch device, pendant device, headphone device, earpiece device, or other wearable or miniature device, a handheld device such as a cellular telephone, a media player, or other small portable device. Device  10  may also be a set-top box, a desktop computer, a display into which a computer or other processing circuitry has been integrated, a display without an integrated computer, a wireless access point, wireless base station, an electronic device incorporated into a kiosk, building, or vehicle, or other suitable electronic equipment. 
     Device  10  may include a housing such as housing  12 . Housing  12 , which may sometimes be referred to as a case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of these materials. In some situations, parts of housing  12  may be formed from dielectric or other low-conductivity material (e.g., glass, ceramic, plastic, sapphire, etc.). In other situations, housing  12  or at least some of the structures that make up housing  12  may be formed from metal elements. 
     Device  10  may, if desired, have a display such as display  14 . Display  14  may be mounted on the front face of device  10 . Display  14  may be a touch screen that incorporates capacitive touch electrodes or may be insensitive to touch. The rear face of housing  12  (i.e., the face of device  10  opposing the front face of device  10 ) may have a substantially planar housing wall such as rear housing wall  12 R (e.g., a planar housing wall). Rear housing wall  12 R may have slots that pass entirely through the rear housing wall and that therefore separate portions of housing  12  from each other. Rear housing wall  12 R may include conductive portions and/or dielectric portions. If desired, rear housing wall  12 R may include a planar metal layer covered by a thin layer or coating of dielectric such as glass, plastic, sapphire, or ceramic. Housing  12  may also have shallow grooves that do not pass entirely through housing  12 . The slots and grooves may be filled with plastic or other dielectric. If desired, portions of housing  12  that have been separated from each other (e.g., by a through slot) may be joined by internal conductive structures (e.g., sheet metal or other metal members that bridge the slot). 
     Housing  12  may include peripheral housing structures such as peripheral structures  12 W. Peripheral structures  12 W and rear housing wall  12 R may sometimes be referred to herein collectively as conductive structures of housing  12 . Peripheral structures  12 W may run around the periphery of device  10  and display  14 . In configurations in which device  10  and display  14  have a rectangular shape with four edges, peripheral structures  12 W may be implemented using peripheral housing structures that have a rectangular ring shape with four corresponding edges and that extend from rear housing wall  12 R to the front face of device  10  (as an example). Peripheral structures  12 W or part of peripheral structures  12 W may serve as a bezel for display  14  (e.g., a cosmetic trim that surrounds all four sides of display  14  and/or that helps hold display  14  to device  10 ) if desired. Peripheral structures  12 W may, if desired, form sidewall structures for device  10  (e.g., by forming a metal band with vertical sidewalls, curved sidewalls, etc.). 
     Peripheral housing structures  12 W may be formed of a conductive material such as metal and may therefore sometimes be referred to as peripheral conductive housing structures, conductive housing structures, peripheral metal structures, peripheral conductive sidewalls, peripheral conductive sidewall structures, conductive housing sidewalls, peripheral conductive housing sidewalls, sidewalls, sidewall structures, or a peripheral conductive housing member (as examples). Peripheral conductive housing structures  12 W may be formed from a metal such as stainless steel, aluminum, or other suitable materials. One, two, or more than two separate structures may be used in forming peripheral conductive housing structures  12 W. 
     It is not necessary for peripheral conductive housing structures  12 W to have a uniform cross-section. For example, the top portion of peripheral conductive housing structures  12 W may, if desired, have an inwardly protruding lip that helps hold display  14  in place. The bottom portion of peripheral conductive housing structures  12 W may also have an enlarged lip (e.g., in the plane of the rear surface of device  10 ). Peripheral conductive housing structures  12 W may have substantially straight vertical sidewalls, may have sidewalls that are curved, or may have other suitable shapes. In some configurations (e.g., when peripheral conductive housing structures  12 W serve as a bezel for display  14 ), peripheral conductive housing structures  12 W may run around the lip of housing  12  (i.e., peripheral conductive housing structures  12 W may cover only the edge of housing  12  that surrounds display  14  and not the rest of the sidewalls of housing  12 ). 
     If desired, rear housing wall  12 R may be formed from a metal such as stainless steel or aluminum and may sometimes be referred to herein as conductive rear housing wall  12 R or conductive rear wall  12 R. Conductive rear housing wall  12 R may lie in a plane that is parallel to display  14 . In configurations for device  10  in which rear housing wall  12 R is formed from metal, it may be desirable to form parts of peripheral conductive housing structures  12 W as integral portions of the housing structures forming the conductive rear housing wall of housing  12 . For example, conductive rear housing wall  12 R of device  10  may be formed from a planar metal structure and portions of peripheral conductive housing structures  12 W on the sides of housing  12  may be formed as flat or curved vertically extending integral metal portions of the planar metal structure (e.g., housing structures  12 R and  12 W may be formed from a continuous piece of metal in a unibody configuration). Housing structures such as these may, if desired, be machined from a block of metal and/or may include multiple metal pieces that are assembled together to form housing  12 . Conductive rear housing wall  12 R may have one or more, two or more, or three or more portions. Peripheral conductive housing structures  12 W and/or the conductive rear housing wall  12 R may form one or more exterior surfaces of device  10  (e.g., surfaces that are visible to a user of device  10 ) and/or may be implemented using internal structures that do not form exterior surfaces of device  10  (e.g., conductive housing structures that are not visible to a user of device  10  such as conductive structures that are covered with layers such as thin cosmetic layers, protective coatings, and/or other coating layers that may include dielectric materials such as glass, ceramic, plastic, or other structures that form the exterior surfaces of device  10  and/or serve to hide structures  12 W and/or  12 R from view of the user). 
     Display  14  may have an array of pixels that form an active area AA that displays images for a user of device  10 . For example, active area AA may include an array of display pixels. The array of pixels may be formed from liquid crystal display (LCD) components, an array of electrophoretic pixels, an array of plasma display pixels, an array of organic light-emitting diode display pixels or other light-emitting diode pixels, an array of electrowetting display pixels, or display pixels based on other display technologies. If desired, active area AA may include touch sensors such as touch sensor capacitive electrodes, force sensors, or other sensors for gathering a user input. 
     Display  14  may have an inactive border region that runs along one or more of the edges of active area AA. Inactive area IA may be free of pixels for displaying images and may overlap circuitry and other internal device structures in housing  12 . To block these structures from view by a user of device  10 , the underside of the display cover layer or other layers in display  14  that overlaps inactive area IA may be coated with an opaque masking layer in inactive area IA. The opaque masking layer may have any suitable color. 
     Display  14  may be protected using a display cover layer such as a layer of transparent glass, clear plastic, transparent ceramic, sapphire, or other transparent crystalline material, or other transparent layer(s). The display cover layer may have a planar shape, a convex curved profile, a shape with planar and curved portions, a layout that includes a planar main area surrounded on one or more edges with a portion that is bent out of the plane of the planar main area, or other suitable shapes. The display cover layer may cover the entire front face of device  10 . In another suitable arrangement, the display cover layer may cover substantially all of the front face of device  10  or only a portion of the front face of device  10 . 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. An opening may also be formed in the display cover layer to accommodate ports such as speaker port  8  or a microphone port. Openings may be formed in housing  12  to form communications ports (e.g., an audio jack port, a digital data port, etc.) and/or audio ports for audio components such as a speaker and/or a microphone if desired. 
     Display  14  may include conductive structures such as an array of capacitive electrodes for a touch sensor, conductive lines for addressing pixels, driver circuits, etc. Housing  12  may include internal conductive structures such as metal frame members and a planar conductive housing member (sometimes referred to as a backplate) that spans the walls of housing  12  (i.e., a substantially rectangular sheet formed from one or more metal parts that is welded or otherwise connected between opposing sides of member  16 ). The backplate may form an exterior rear surface of device  10  or may be covered by layers such as thin cosmetic layers, protective coatings, and/or other coatings that may include dielectric materials such as glass, ceramic, plastic, or other structures that form the exterior surfaces of device  10  and/or serve to hide the backplate from view of the user. Device  10  may also include conductive structures such as printed circuit boards, components mounted on printed circuit boards, and other internal conductive structures. These conductive structures, which may be used in forming a ground plane in device  10 , may extend under active area AA of display  14 , for example. 
     In regions  22  and  20 , openings may be formed within the conductive structures of device  10  (e.g., between peripheral conductive housing structures  12 W and opposing conductive ground structures such as conductive portions of conductive rear housing wall  12 R, conductive traces on a printed circuit board, conductive electrical components in display  14 , etc.). These openings, which may sometimes be referred to as gaps, may be filled with air, plastic, and/or other dielectrics and may be used in forming slot antenna resonating elements for one or more antennas in device  10 , if desired. 
     Conductive housing structures and other conductive structures in device  10  may serve as a ground plane for the antennas in device  10 . The openings in regions  20  and  22  may serve as slots in open or closed slot antennas, may serve as a central dielectric region that is surrounded by a conductive path of materials in a loop antenna, may serve as a space that separates an antenna resonating element such as a strip antenna resonating element or an inverted-F antenna resonating element from the ground plane, may contribute to the performance of a parasitic antenna resonating element, or may otherwise serve as part of antenna structures formed in regions  20  and  22 . If desired, the ground plane that is under active area AA of display  14  and/or other metal structures in device  10  may have portions that extend into parts of the ends of device  10  (e.g., the ground may extend towards the dielectric-filled openings in regions  20  and  22 ), thereby narrowing the slots in regions  20  and  22 . 
     In general, device  10  may include any suitable number of antennas (e.g., one or more, two or more, three or more, four or more, etc.). The antennas in device  10  may be located at opposing first and second ends of an elongated device housing (e.g., at ends  20  and  22  of device  10  of  FIG. 1 ), along one or more edges of a device housing, in the center of a device housing, in other suitable locations, or in one or more of these locations. The arrangement of  FIG. 1  is merely illustrative. 
     Portions of peripheral conductive housing structures  12 W may be provided with peripheral gap structures. For example, peripheral conductive housing structures  12 W may be provided with one or more gaps such as gaps  18 , as shown in  FIG. 1 . The gaps in peripheral conductive housing structures  12 W may be filled with dielectric such as polymer, ceramic, glass, air, other dielectric materials, or combinations of these materials. Gaps  18  may divide peripheral conductive housing structures  12 W into one or more peripheral conductive segments. There may be, for example, two peripheral conductive segments in peripheral conductive housing structures  12 W (e.g., in an arrangement with two of gaps  18 ), three peripheral conductive segments (e.g., in an arrangement with three of gaps  18 ), four peripheral conductive segments (e.g., in an arrangement with four of gaps  18 ), six peripheral conductive segments (e.g., in an arrangement with six gaps  18 ), etc. The segments of peripheral conductive housing structures  12 W that are formed in this way may form parts of antennas in device  10 . 
     If desired, openings in housing  12  such as grooves that extend partway or completely through housing  12  may extend across the width of the rear wall of housing  12  and may penetrate through the rear wall of housing  12  to divide the rear wall into different portions. These grooves may also extend into peripheral conductive housing structures  12 W and may form antenna slots, gaps  18 , and other structures in device  10 . Polymer or other dielectric may fill these grooves and other housing openings. In some situations, housing openings that form antenna slots and other structure may be filled with a dielectric such as air. 
     In a typical scenario, device  10  may have one or more upper antennas and one or more lower antennas (as an example). An upper antenna may, for example, be formed at the upper end of device  10  in region  22 . A lower antenna may, for example, be formed at the lower end of device  10  in region  20 . The antennas may be used separately to cover identical communications bands, overlapping communications bands, or separate communications bands. The antennas may be used to implement an antenna diversity scheme or a multiple-input-multiple-output (MIMO) antenna scheme. 
     Antennas in device  10  may be used to support any communications bands of interest. For example, device  10  may include antenna structures for supporting local area network communications, voice and data cellular telephone communications, global positioning system (GPS) communications or other satellite navigation system communications, Bluetooth® communications, near-field communications, etc. 
     In order to provide an end user of device  10  with as large of a display as possible (e.g., to maximize an area of the device used for displaying media, running applications, etc.), it may be desirable to increase the amount of area at the front face of device  10  that is covered by active area AA of display  14 . Increasing the size of active area AA may reduce the size of inactive area IA within device  10 . This may reduce the area of regions  20  and  22  that is available for forming antennas within device  10 . In general, antennas that are provided with larger operating volumes or spaces may have higher bandwidth efficiency than antennas that are provided with smaller operating volumes or spaces. If care is not taken, increasing the size of active area AA may reduce the operating space available to the antennas, which can undesirably inhibit the efficiency bandwidth of the antennas (e.g., such that the antennas no longer exhibit satisfactory radio-frequency performance). It would therefore be desirable to be able to provide antennas that occupy a small amount of space within device  10  (e.g., to allow for as large of a display active area AA as possible) while still allowing the antennas to operate with optimal efficiency bandwidth. 
     A schematic diagram showing illustrative components that may be used in device  10  of  FIG. 1  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 Wi-Fi®), protocols for other short-range wireless communications links such as the Bluetooth® protocol or other wireless personal area network protocols, cellular telephone protocols, multiple-input and multiple-output (MIMO) protocols, antenna diversity protocols, near-field communications (NFC) protocols, etc. 
     Input-output circuitry  30  may include input-output devices  32 . Input-output devices  32  may be used to allow data to be supplied to device  10  and to allow data to be provided from device  10  to external devices. Input-output devices  32  may include user interface devices, data port devices, and other input-output components. For example, input-output devices  32  may include touch screens, displays without touch sensor capabilities, buttons, 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, position and orientation sensors (e.g., sensors such as accelerometers, gyroscopes, and compasses), capacitance sensors, proximity sensors (e.g., capacitive proximity sensors, light-based proximity sensors, etc.), fingerprint sensors (e.g., a fingerprint sensor integrated with a button), etc. 
     Input-output circuitry  30  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  24  for handling various radio-frequency communications bands. For example, circuitry  34  may include transceiver circuitry  36 ,  38 , and  42 . Transceiver circuitry  36  may handle wireless local area network (WLAN) bands such as 2.4 GHz and 5 GHz bands for WiFi® (IEEE 802.11) communications and/or wireless personal area network (WPAN) bands such as 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 low-midband from 960 to 1710 MHz, a midband from 1710 to 2170 MHz, a high band from 2300 to 2700 MHz, an ultra-high band from 3400 to 3700 MHz or other communications bands between 600 MHz and 4000 MHz or other suitable frequencies (as examples). 
     Circuitry  38  may handle voice data and non-voice 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. Wireless communications circuitry  34  may include global positioning system (GPS) receiver equipment such as GPS receiver circuitry  42  for receiving GPS signals at 1575 MHz or for handling other satellite positioning data (e.g., Global Navigation Satellite System (GLONASS) signals, etc.). In Wi-Fi® 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. 
     Wireless circuitry  34  may include near-field communications circuitry  44  (sometimes referred to herein as near-field communications transceiver circuitry  44 , near-field communications transceiver circuits  44 , near-field communications transceiver  44 , near-field circuitry  44 , near-field transceiver circuitry  44 , or near-field transceiver  44 ). Near-field communications transceiver circuitry  44  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 typically are 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, dipole antenna structures, monopole 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. The structures of antennas  40  may also be used in gathering proximity sensor signals (e.g., capacitive proximity sensor signals). 
     Radio-frequency transceiver circuitry  24  does not handle near-field communications signals and is therefore sometimes referred to as far-field communications circuitry, non-near-field communications circuitry, non-near-field circuitry, or non-near-field communications transceiver circuitry. Near-field communications transceiver circuitry  44  is 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 or other frequencies below 600 MHz. Other near-field communications bands may be supported using the structures of antennas  40  if desired. Frequencies handled by near-field communications transceiver circuitry  44  in performing near-field communications using wireless near-field communications signals may sometimes be referred to herein as near-field communications frequencies. Transceiver circuitry  90  may handle non-near-field communications frequencies (e.g., frequencies above 600 MHz or other suitable frequencies). 
     The structures forming antennas  40  may sometimes be collectively referred to herein as antenna structures  40 . As shown in  FIG. 3 , antenna structures  40  may be coupled to near-field communications circuitry such as near-field communications transceiver circuitry  44  and non-near-field communications circuitry such as non-near-field communications transceiver circuitry  24 . 
     Non-near-field communications transceiver circuitry  24  in wireless communications circuitry  34  may be coupled to antenna structures  40  using paths such as path  92 . Near-field communications transceiver circuitry  44  may be coupled to antenna structures  40  using paths such as path  110 . Paths such as path  104  may be used to allow control circuitry  28  to transmit near-field communications data and to receive near-field communications data using near-field transceiver circuitry  44  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 such as antenna(s)  40  with the ability to cover communications frequencies of interest, antenna(s)  40  may be provided with circuitry such as filter circuitry (e.g., one or more passive filters and/or one or more tunable filter circuits). Discrete components such as capacitors, inductors, and resistors may be incorporated into the filter circuitry. Capacitive structures, inductive structures, and resistive structures may also be formed from patterned metal structures (e.g., part of an antenna). If desired, antenna(s)  40  may be provided with adjustable circuits such as tunable components  102  to tune antennas over communications bands of interest. Tunable components  102  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. 
     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. During operation of device  10 , control circuitry  28  may issue control signals on one or more paths such as path  108  that adjust inductance values, capacitance values, or other parameters associated with tunable components  102 , thereby tuning antenna structures  40  to cover desired communications bands. 
     During operation of device  10 , control circuitry  28  may issue control signals on one or more paths such as path  108  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  24  and near-field communications transceiver circuitry  44 . Near-field communications and non-near-field communications may also be handled using two or more separate antennas, if desired. 
     Path  92  may include one or more transmission lines. As an example, path  92  of  FIG. 3  may be a radio-frequency transmission line having a positive signal conductor such as conductor  94  and a ground signal conductor such as conductor  96 . Transmission line structures used to form path  92  (sometimes referred to herein as transmission lines  92  or radio-frequency transmission lines  92 ) may include parts of a coaxial cable, a stripline transmission line, microstrip transmission line, coaxial probes realized by metalized vias, edge-coupled microstrip transmission lines, edge-coupled stripline transmission lines, waveguide structures, transmission lines formed from combinations of transmission lines of these types, etc. 
     Transmission lines in device  10  may be integrated into rigid and/or flexible printed circuit boards. In one suitable arrangement, transmission lines in device  10  may also include transmission line conductors (e.g., signal and ground conductors) 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) that may be folded or bent in multiple dimensions (e.g., two or three dimensions) and that 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 (e.g., an adjustable matching network formed using tunable components  102 ) may include components such as inductors, resistors, and capacitors used in matching the impedance of antenna(s)  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 in antenna(s)  40  and may be tunable and/or fixed components. 
     Transmission line  92  may be coupled to antenna feed structures associated with antenna structures  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  112  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  100 . Other types of antenna feed arrangements may be used if desired. For example, antenna structures  40  may be fed using multiple feeds. 
     Path  110  may include transmission line structures or other conductive lines that couple near-field communications transceiver circuitry  44  to near-field communications antenna feed terminals of a near-field communications antenna feed on antenna structures  40 . The near-field communications antenna feed may be formed using antenna feed  112  or may be formed separately from antenna feed  112 . Path  110  (sometimes referred to herein as radio-frequency transmission line  110 , transmission line  110 , or transmission line path  110 ) may, for example, include a single-ended signal path for conveying single-ended near-field communications antenna signals between near-field communications transceiver circuitry  44  and antenna structures  40 . In another suitable arrangement, path  110  may include a differential signal path for conveying differential near-field communications antenna signals between near-field communications transceiver circuitry  44  and antenna structures  40 . The illustrative feeding configuration of  FIG. 3  is merely illustrative. 
     If desired, control circuitry  28  may use an impedance measurement circuit to gather antenna impedance information. Control circuitry  28  may use information from a proximity sensor (see, e.g., sensors  32  of  FIG. 2 ), received signal strength information, device orientation information from an orientation sensor, information about a usage scenario of device  10 , information about whether audio is being played through speaker  8  ( FIG. 1 ), information from one or more antenna impedance sensors, or other information in determining when antenna structures  40  are being affected by the presence of nearby external objects or is otherwise in need of tuning. In response, control circuitry  28  may adjust an adjustable inductor, adjustable capacitor, switch, or other tunable component  102  to ensure that antenna structures  40  operate as desired. Adjustments to tunable components  102  may also be made to extend the coverage of antenna structures  40  (e.g., to cover desired communications bands that extend over a range of frequencies larger than the antenna structures would cover without tuning). 
     Antenna structures  40  may include resonating element structures (sometimes referred to herein as radiating element structures), antenna ground plane structures (sometimes referred to herein as ground plane structures, ground structures, or antenna ground structures), an antenna feed such as antenna feed  112  and a near-field communications antenna feed, and other components (e.g., tunable components  102 ). Antenna structures  40  may be configured to form any suitable types of antennas. With one suitable arrangement, which is sometimes described herein as an example, antenna structures  40  may be used to implement a slot antenna structure. 
     An illustrative slot antenna structure that may be used for forming antenna structures  40  is shown in  FIG. 4 . As shown in  FIG. 4 , antenna structures  40  may include a conductive structure such as structure  136  that has been provided with a dielectric-filled opening such as dielectric opening  140 . Openings such as opening  140  of  FIG. 4  are sometimes referred to as slots, slot elements, slot resonating elements, or slot antenna resonating elements of antenna structures  40 . In the configuration of  FIG. 4 , slot  140  is a closed slot, because portions of conductive structure  136  completely surround and enclose slot  140 . Open slot antenna structures may also be formed in conductive materials such as conductive structure  136  (e.g., by forming an opening in the right-hand or left-hand end of conductive structure  136  so that slot  140  protrudes through conductive structure  136 ). 
     Antenna feed  112  for antenna structures  40  may be formed using positive antenna feed terminal  98  and ground antenna feed terminal  100 . In general, the frequency response of an antenna is related to the size and shapes of the conductive structures in the antenna. Slot antenna structures of the type shown in  FIG. 4  tend to exhibit response peaks when slot perimeter P is equal to the wavelength of operation of the antenna (e.g. where perimeter P is equal to two times length L plus two times width W). Antenna currents may flow between feed terminals  98  and  100  around perimeter P of slot  140 . 
     Antenna feed  112  may be coupled across slot  140  at a location along length L. For example, antenna feed  112  may be located at a distance  134  from one side of slot  140 . Distance  134  may be adjusted to match the impedance of antenna structures  40  to the impedance of the corresponding transmission line (e.g., transmission line  92  of  FIG. 3 ). For example, the antenna current flowing around slot  140  may experience an impedance of zero at the left and right edges of slot  140  (e.g., a short circuit impedance) and an infinite (open circuit) impedance at the center of slot  140  (e.g., at a fundamental frequency of the slot). Location  134  may be located between the center of slot  140  and the left edge at a location where the antenna current experiences an impedance that matches the impedance of the corresponding transmission line, for example (e.g., distance  134  may be between 0 and ¼ of the wavelength of operation of antenna structures  40 ). Distance  134  may, for example, be 9 mm, between 5 mm and 10 mm, between 2 mm and 12 mm, or any other suitable distance. Slot  140  may have a width W perpendicular to length L. 
     In scenarios where slot  140  is a closed slot, length L may be approximately equal to (e.g., within 15% of) one half of a wavelength of operation of the antenna (e.g., a wavelength of a fundamental mode of the antenna). Harmonic modes of slot  140  may also be configured to cover desired frequency bands. In scenarios where slot  140  is an open slot, the length of slot element  140  may be approximately equal to one quarter of the wavelength of the antenna. The wavelength of operation may, for example, be an effective wavelength of operation based on the dielectric material within slot  140 . 
     The frequency response of slot  140  can be tuned using one or more tuning components (e.g., tunable components  102  of  FIG. 3 ). These components may have terminals that are coupled to opposing sides of slot  140  (i.e., the tunable components may bridge the slot). If desired, tunable components may have terminals that are coupled to respective locations along the length of one of the sides of slot  140 . Combinations of these arrangements may also be used. 
     The example of  FIG. 4  is merely illustrative. In general, slot  140  may have any desired shape (e.g., where the perimeter P of slot  140  defines radiating characteristics of the antenna). For example, slot  140  may have a meandering shape with different segments extending in different directions, may have straight and/or curved edges, may have more than one open end, etc. Conductive structure  136  may be formed from any desired conductive electronic device structures. For example, conductive structure  136  may include conductive traces on printed circuit boards or other substrates, sheet metal, metal foil, conductive structures associated with display  14  ( FIG. 1 ), conductive portions of housing  12  (e.g., conductive structures  12 W and/or  12 R of  FIG. 1 ), and/or other conductive structures within device  10 . In one suitable arrangement, different sides (edges) of slot  140  may be defined by different conductive structures. 
     In the example of  FIG. 4 , a single antenna is shown. When operating using a single antenna, a single stream of wireless data may be conveyed between device  10  and external communications equipment (e.g., one or more other wireless devices such as wireless base stations, access points, cellular telephones, computers, etc.). This may impose an upper limit on the data rate (data throughput) obtainable by wireless communications circuitry  34  in communicating with the external communications equipment. As software applications and other device operations increase in complexity over time, the amount of data that needs to be conveyed between device  10  and the external communications equipment typically increases, such that a single antenna may not be capable of providing sufficient data throughput for handling the desired device operations. 
     In order to increase the overall data throughput of wireless circuitry  34 , multiple antennas may be operated using a multiple-input and multiple-output (MIMO) scheme. When operating using a MIMO scheme, two or more antennas on device  10  may be used to convey multiple independent streams of wireless data at the same frequencies. This may significantly increase the overall data throughput between device  10  and the external communications equipment relative to scenarios where only a single antenna is used. In general, the greater the number of antennas that are used for conveying wireless data under the MIMO scheme, the greater the overall throughput of circuitry  34 . 
     A top interior view of an illustrative device  10  that contains multiple antennas (e.g., for performing communications under a MIMO scheme) is shown in  FIG. 5 . As shown in  FIG. 5 , device  10  may have peripheral conductive housing structures such as peripheral conductive housing structures  12 W (sometimes referred to herein as peripheral conductive housing sidewalls  12 W). In the example of  FIG. 5 , display  14  is not shown for the sake of clarity. 
     Peripheral conductive housing sidewalls  12 W may be segmented by dielectric-filled gaps (e.g., plastic gaps)  18  such as a first gap  18 - 1 , a second gap  18 - 2 , and a third gap  18 - 3 . Each of gaps  18 - 1 ,  18 - 2 , and  18 - 3  may be formed within peripheral conductive housing sidewalls  12 W along respective sides of device  10 . Gap  18 - 1  may separate segment  178  of peripheral conductive housing sidewalls  12 W from the segment of peripheral conductive housing sidewalls  12 W below gap  18 - 1 . Gap  18 - 2  may separate segment  176  of peripheral conductive housing sidewalls  12 W from the segment of peripheral conductive housing sidewalls  12 W below gap  18 - 2 . Gap  18 - 3  may separate segment  178  from segment  176  of peripheral conductive housing sidewalls  12 W. Gaps  18 - 1 ,  18 - 2 , and  18 - 3  may be filled with plastic, ceramic, sapphire, glass, epoxy, or other dielectric materials. The dielectric material in gaps  18 - 1 ,  18 - 2 , and  18 - 3  may lie flush with peripheral conductive housing sidewalls  12 W at the exterior surface of device  10  if desired. 
     A conductive structure such as conductive layer  150  may extend between opposing peripheral conductive housing sidewalls  12 W. Conductive layer  150  may be formed from conductive housing structures, conductive structures from electrical device components in device  10 , printed circuit board traces, strips of conductor such as strips of wire and metal foil, conductive components in a display (e.g., display  14  of  FIG. 1 ), and/or other conductive structures. In one suitable arrangement, conductive layer  150  is formed from conductive rear wall  12 R ( FIG. 1 ). 
     As shown in  FIG. 5 , conductive layer  150  (e.g., conductive rear housing wall  12 R) may extend between the opposing edges (e.g., the left and right edges) of device  10 . Conductive layer  150  may be formed from a separate metal structure from peripheral conductive housing sidewalls  12 W or conductive layer  150  and peripheral conductive housing sidewalls  12 W may be formed from the same, continuous, integral metal structure (e.g., in a unibody configuration). 
     In the example of  FIG. 5 , antenna structures  40  may include multiple antennas such as a first antenna  170 , a second antenna  172 , and a third antenna  174 . Antennas  170 ,  172 , and  174  may, for example, be non-near-field communications antennas for handling non-near-field communications. Antennas  170 ,  172 , and  174  may include an antenna ground (sometimes referred to herein as ground structures or an antenna ground plane) formed from conductive layer  150  and the segments of peripheral conductive housing walls  12 W below gaps  18 - 1  and  18 - 2 , for example. 
     Antenna  170  may include a first slot  140 - 1  between segment  178  of peripheral conductive housing sidewalls  12 W and conductive layer  150 . Antenna  172  may include a second slot  140 - 2 . Second slot  140 - 2  may have a first edge defined by portions of segments  178  and  176  of peripheral conductive housing sidewalls  12 W and gap  18 - 3  and may have a second opposing edge defined by conductive layer  150 . Antenna  174  may include a third slot  140 - 3  between segment  176  of peripheral conductive housing sidewalls  12 W and conductive layer  150  (e.g., conductive layer  150  and peripheral conductive housing sidewalls  12 W may form conductive structure  136  of  FIG. 4  for antennas  170 ,  172 , and  174 ). 
     Conductive bridging structures such as conductive structures  154  may be coupled between segment  178  of peripheral conductive housing sidewalls  12 W and conductive layer  150 . Conductive structures  154  may electrically isolate slot  140 - 1  from slot  140 - 2  (e.g., conductive structures  154  may define edges of slots  140 - 1  and  140 - 2 ). Conductive bridging structures such as conductive structures  156  may be coupled between segment  176  of peripheral conductive housing sidewalls  12 W and conductive layer  150 . Conductive structures  156  may electrically isolate slot  140 - 2  from slot  140 - 3  (e.g., conductive structures  154  may define edges of slots  140 - 2  and  140 - 3 ). 
     Conductive structures  154  and  156  may, as examples, be formed from metal traces on printed circuits, metal foil, metal members formed from a sheet of metal, conductive portions of housing  12  (e.g., integral portions of conductive rear housing wall  12 R and/or peripheral conductive housing sidewalls  12 W), conductive wires, conductive portions of input-output devices  32  of  FIG. 2  (e.g., conductive portions of display  14 , conductive portions of a camera module or light sensor module, conductive portions of a speaker module, etc.), conductive interconnect structures such as conductive pins, conductive brackets, conductive adhesive, solder, welds, conductive springs, conductive screws, or combinations of these and/or other conductive interconnect structures, conductive foam, switchable or fixed inductive paths, switchable or fixed capacitive paths, and/or any other desired conductive components or structures. Conductive structures  154  need not be formed from the same types of conductive components as conductive structures  156 . 
     Slots  140 - 1 ,  140 - 2 , and  140 - 3  may be filled with plastic, glass, sapphire, epoxy, ceramic, or other dielectric material. Slot  140 - 1  may be continuous with gap  18 - 1  in peripheral conductive housing sidewalls  12 W such that gap  18 - 1  forms an open end of slot  140 - 1  (e.g., a single piece of dielectric material may be used to fill both slot  140 - 1  and gap  18 - 1 ). Slot  140 - 1  may have an opposing closed end  140 - 1  defined by conductive structures  154 . Slot  140 - 2  may be continuous with gap  18 - 3  in peripheral conductive housing sidewalls  12 W such that gap  18 - 3  forms an open end of slot  140 - 2  (e.g., a single piece of dielectric material may be used to fill both slot  140 - 2  and gap  18 - 3 ). Slot  140 - 2  may have a closed end defined by conductive structures  154 . Slot  140 - 3  may be continuous with gap  18 - 2  in peripheral conductive housing sidewalls  12 W such that gap  18 - 2  forms an open end of slot  140 - 3  (e.g., a single piece of dielectric material may be used to fill both slot  140 - 3  and gap  18 - 2 ). Slot  140 - 3  may have an opposing closed end defined by conductive structures  156 . 
     In one suitable arrangement, slots  140 - 1 ,  140 - 2 , and  140 - 3  may be formed from a single continuous dielectric-filled slot at the exterior of device  10  (e.g., where a single continuous piece of dielectric material is used to fill slots  140 - 1 ,  140 - 2 ,  140 - 3 , gap  18 - 1 , gap  18 - 2 , and gap  18 - 3 ). In this scenario, conductive structures  154  and  156  may be formed at the interior of device  10  and serve to electrically divide the continuous dielectric-filled slot into separate slots  140 - 1 ,  140 - 2 , and  140 - 3  (e.g., at the interior of device  10 ). 
     Antenna  170  may be fed using a corresponding antenna feed  112  ( FIGS. 3 and 4 ) such as antenna feed  112 - 1  coupled across slot  140 - 1 . Antenna  172  may be fed using a corresponding antenna feed  112 - 2  coupled across slot  140 - 2 . Antenna  174  may be fed using a corresponding antenna feed  112 - 3  coupled across slot  140 - 3 . Antenna feeds  112 - 1 ,  112 - 2 , and  112 - 3  may be coupled to non-near-field communications transceiver circuitry  24  over corresponding transmission lines  92  ( FIG. 3 ). Antennas  170 ,  172 , and  174  and the corresponding antenna feeds  112 - 1 ,  112 - 2 , and  112 - 3  may handle wireless communications in non-near-field communications frequency bands such as a cellular low band LB, a cellular midband MB, a cellular high band HB, a cellular low-midband from 960 to 1710 MHz, a cellular ultra-high band from 3400 to 3700 MHz, 2.4 GHz and 5 GHz bands for Wi-Fi® (IEEE 802.11) communications, a 1575 MHz band for GPS signals, and/or other non-near-field communications bands. Antennas  170 ,  172 , and  174  may therefore sometimes be referred to herein as non-near-field communications antennas  170 ,  172 , and  174 . Antenna feeds  112 - 1 ,  112 - 2 , and  112 - 3  may sometimes be referred to herein as non-near-field communications antenna feeds. 
     The frequency response of non-near-field communications antenna  170  may be determined by the elongated length of slot  140 - 1  (e.g., the length of the portion of segment  178  of peripheral conductive housing sidewalls  12 W extending from gap  18 - 1  to conductive structures  154 ). For example, this elongated length may be approximately equal to one-quarter of the wavelength of operation of non-near-field communications antenna  170  (e.g., a non-near-field communications wavelength). The frequency response of non-near-field communications antenna  172  may be determined by the elongated length of slot  140 - 2 . 
     If desired, the electrical length of slot  140 - 2  may be adjusted using a filter or frequency-dependent component such as capacitive circuit  160  (e.g., a network of one or more capacitors coupled in series and/or in parallel). Capacitive circuit  160  may be coupled between segment  176  and conductive layer  150  across slot  140 - 2 . Capacitive circuit  160  may have a selected capacitance so that capacitive circuit  160  forms a short circuit between segment  176  and conductive layer  150  at relatively high frequencies such as non-near-field communications frequencies and so that capacitive circuit  160  forms an open circuit at relatively low frequencies such as near-field communications frequencies. In this way, capacitive circuit  160  may shorten the effective or electrical length of slot  140 - 2  at relatively high frequencies such as the non-near-field communications frequencies handled by antenna feed  112 - 2  of non-near-field communications antenna  172 . This may configure slot  140 - 2  to have has closed ends formed by conductive structures  154 , conductive layer  150 , and capacitive circuit  160  and an open end formed by gap  18 - 3  at non-near-field communications frequencies (e.g., so that the effective length of slot  140 - 2  extends from conductive structures  154  to the exterior surface of gap  18 - 3 ). This effective length may be selected to be approximately one-quarter of the wavelength of operation of non-near-field communications antenna  172 , for example. At the same time, capacitive circuit  160  may allow slot  140 - 2  to be as electrically large as possible at relatively low frequencies such as near-field communications frequencies. 
     The frequency response of non-near-field communications antenna  174  may be determined by the elongated length of slot  140 - 1  extending from conductive structures  156  to gap  18 - 2  (e.g., the length of segment  176  of peripheral conductive housing sidewalls  12 W extending from gap  18 - 3  to conductive structures  156 ). For example, this elongated length may be approximately equal to one-quarter of the wavelength of operation of non-near-field communications antenna  174  (e.g., a non-near-field communications wavelength). The elongated lengths of slot  140 - 1 ,  140 - 2 , and  140 - 3  (e.g., length L of  FIG. 4 ) may, if desired, include the vertical height of gaps  18 - 1 ,  18 - 3 , and  18 - 2 , respectively (e.g., the lengths of gaps  18 - 1 ,  18 - 3 , and  18 - 2  extending up the vertical height of peripheral conductive housing sidewalls  12 W from conductive rear housing wall  12 R to display  14  as shown by gaps  18  in  FIG. 1 ). 
     In the example of  FIG. 5 , slots  140 - 1  and  140 - 3  have meandering shapes that conform to the corners of device  10  whereas slot  140 - 2  has a rectangular shape that extends parallel to the top edge of device  10 ). This example is merely illustrative. In general, slots  140 - 1 ,  140 - 2 , and  140 - 3  may be straight or may have any desired shape having any desired number of segments and straight and/or curved edges. While the example of  FIG. 5  shows antenna structures  40  formed within region  22  at the upper end of device  10 , similar structures may additionally or alternatively be formed within region  20  at the lower end of device  10  if desired ( FIG. 1 ). 
     In order to enhance the data throughput of wireless circuitry  34 , non-near-field communications transceiver circuitry  24  ( FIG. 3 ) may perform communications at non-near-field communications frequencies under a MIMO scheme using non-near-field communications antennas  170 ,  172 , and/or  174 . In order to perform MIMO communications, non-near-field communications transceiver circuitry  24  may convey radio-frequency signals at the same frequencies (e.g., in the same frequency band) over non-near-field communications antennas  170 ,  172 , and/or  174 . Antenna tuning components (e.g., tunable components  102  of  FIG. 3 ) may be coupled across slots  140 - 1 ,  140 - 2 , and/or  140 - 3  for tuning the non-near-field communications frequency response of non-near-field communications antennas  170 ,  172 , and/or  174 , respectively. 
     To support near-field communications in device  10 , device  10  preferably includes a dedicated near-field communications antenna. Space can be conserved by using some or all of antenna structures  40  (e.g., non-near-field communications antennas  170 ,  172 , and/or  174 ) as both non-near-field communications antennas and as a near-field communications antenna. As an example, a near-field communications antenna for device  10  (e.g., an antenna that is used by near-field communications transceiver circuitry  44 ) may be formed using portions of antenna structures  40  such as portions of segments  178  and  176  of peripheral conductive housing sidewalls  12 W, conductive structures  154  and  156 , and conductive layer  150 . In the example of  FIG. 5 , antenna structures  40  include a near-field communications antenna as illustrated by conductive loop path  166  (sometimes referred to herein as near-field communications antenna  166 , near-field communications loop antenna  166 , or loop antenna  166 ). By sharing conductive antenna structures between both near-field and non-near-field communications antennas, duplicative conductive structures can be minimized and antenna volume can be conserved within device  10 . 
     As shown in  FIG. 5 , near-field communications antenna  166  for device  10  may be formed from a portion of non-near-field communications antenna  170  such as conductive structures  154 . Near-field communications antenna  166  may be formed from portions of non-near-field communications antenna  172  such as the portions of segments  178  and  176  defining edges of slot  140 - 2 , conductive structures  154 , conductive structures  156 , and the portion of conductive layer  150  defining edges of slot  140 - 2 . Near-field communications antenna  166  may be formed from a portion of non-near-field communications antenna  174  such as conductive structures  156 . 
     In order to support near-field communications using near-field communications antenna  166 , near-field communications transceiver circuitry  44  (NFC TX/RX) may transmit and/or receive near-field communications signals (e.g., radio-frequency signals in a near-field communications band such as a 13.56 MHz near-field communications band). Near-field communications transceiver circuitry  44  may be mounted to a substrate  152  such as a main logic board for device  10 . Near-field communications transceiver circuitry  44  may be coupled to near-field communications antenna  166  using a transmission line  110  ( FIG. 3 ) such as transmission line  110 S. In the example of  FIG. 5 , transmission line  110 S is a single-ended signal path (sometimes referred to herein as a single-ended signal transmission line) for conveying single-ended near-field communications signals between near-field communications antenna  166  and near-field communications transceiver circuitry  44 . 
     Near-field communications antenna  166  may include a single-ended antenna feed coupled to peripheral conductive housing sidewalls  12 W across gap  18 - 3 . The single-ended antenna feed may include a positive antenna feed terminal  164  (sometimes referred to herein as positive near-field communications antenna feed terminal  164 ) coupled to segment  176  and a ground antenna feed terminal  162  (sometimes referred to herein as ground near-field communications antenna feed terminal  162 ) coupled to segment  178 . Transmission line  110 S may include a ground conductor coupled to ground antenna feed terminal  162  and may include a single conductor coupled to positive antenna feed terminal  164 . In one suitable arrangement, transmission line  110 S may be a coaxial cable having a ground conductor formed from an outer conductive braid surrounding the signal conductor. 
     If desired, a filter such as a frequency-dependent circuit based on inductor  158  (e.g., an inductor having an inductance L) may be interposed on the signal conductor of transmission line  110 S. Inductance L of inductor  158  may be selected so that inductor  158  forms a short circuit path to antenna feed terminal  164  at relatively low frequencies such as near-field communications frequencies and so that inductor  158  forms an open circuit at relatively high frequencies such as non-near-field communications frequencies. In this way, inductor  158  may serve to isolate near-field communications transceiver circuitry  44  from radio-frequency signals at non-near-field communications frequencies handled by antennas  170 ,  172 , and/or  174 . In the example of  FIG. 5 , near-field communications transceiver circuitry  44  may, if desired, include balun circuitry or other circuitry for converting the single-ended signals into differential signals and for converting differential signals into the single-ended signals. 
     Near-field-communications transceiver circuitry  44  may convey near-field communications signals over near-field communications antenna  166  via transmission line  110 S. Corresponding antenna currents I 1  (e.g., currents at near-field communications frequencies) may flow over the conductive loop path extending between antenna feed terminals  164  and  162 . For example, antenna current I 1  may flow from positive antenna feed terminal  164  over the portion of segment  176  between positive antenna feed terminal  164  and conductive structures  156 , over conductive structures  156 , from conductive structures  156  to conductive structures  154  over conductive layer  150  (e.g., the antenna ground for non-near-field communications antenna  172 ), over conductive structures  154 , and then over the portion of segment  178  from conductive structures  154  to ground antenna feed terminal  162 . 
     Capacitive circuit  160  may form an open circuit at the near-field communications frequency of antenna current I 1 . Antenna current I 1  may therefore flow over segment  176  without being shorted to conductive layer  150  through capacitive circuit  160 . This may serve to increase the overall size (area) of near-field communications antenna  166  relative to scenarios where a short circuit path is formed in place of capacitive circuit  160  (without affecting the path of antenna currents handled by non-near-field communications antenna  172  at higher non-near-field communications frequencies). Increasing the size of near-field communications antenna  166  in this way may, for example, facilitate the use of device  10  for a user who is using device  10  to communicate with external near-field communications equipment such as an RFID reader (e.g., so that the user does not have to focus on precisely placing device  10  over the RFID reader so that the antenna volume is aligned with the RFID reader). 
     In the example of  FIG. 5 , antenna current I 1  may exhibit a greater strength over segment  176 , conductive structures  156 , and conductive layer  150  than over conductive structures  154  and segment  178  (e.g., relatively strong antenna current I 1  is illustrated by a solid line in  FIG. 5  whereas relatively weak current I 1  is illustrated by a dashed line). This may, for example, limit the reliability of near-field communications antenna  166  when communicating with an external device such as an RFID reader held towards the left of near-field communications antenna  166  as shown in  FIG. 5 . If desired, near-field communications antenna  166  may be fed using differential signals to provide a more uniform antenna current across the entire area of near-field communications antenna  166 . 
       FIG. 6  is a top interior view of device  10  showing how near-field communications antenna  166  may be fed using differential signals. As shown in  FIG. 6 , near-field communications transceiver circuitry  44  may have a differential output having terminals  210  and  206 . Terminals  210  and  206  of near-field communications transceiver circuitry  44  may form a pair of differential signal terminals. Near-field communications antenna  166  may be fed using a differential pair of antenna feed terminals such as antenna feed terminals  212  and  214 . Antenna feed terminal  212  (sometimes referred to herein as first differential antenna feed terminal  212 ) may be coupled to segment  178  of peripheral conductive housing sidewalls  12 W at or adjacent to gap  18 - 3 . Antenna feed terminal  214  (sometimes referred to herein as second differential antenna feed terminal  214 ) may be coupled to segment  176  of peripheral conductive housing sidewalls  12 W at or adjacent to gap  18 - 3 . 
     The differential output of near-field communications transceiver circuitry  44  may be coupled to near-field communications antenna  166  over transmission line  110 D. Transmission line  110 D may be a differential signal path (sometimes referred to herein as a differential signal transmission line). Transmission line  110 D may include a first conductor  200  coupled between antenna feed terminal  212  of near-field communications antenna  166  and terminal  210  on near-field communications transceiver circuitry  44 . Transmission line  110 D may include a second conductor  202  coupled between antenna feed terminal  214  of near-field communications antenna  166  and terminal  206  on near-field communications transceiver circuitry  44 . Near-field communications transceiver circuitry  44  may be coupled to ground via ground terminal  204 . 
     During operation of near-field communications transceiver circuitry  44 , differential signals across terminals  210  and  206  are transmitted and received by near-field communications antenna  166 . The differential signals may include a differential signal pair S+/S−. Differential signal S+ of the differential signal pair may be conveyed over terminal  210 , conductor  200 , and antenna feed terminal  212 . Differential signal S− of the differential signal pair may be conveyed over terminal  206 , conductor  202 , and antenna feed terminal  214 . Antenna currents I 2  (e.g., loop currents) corresponding to the differential signals may flow between antenna feed terminals  212  and  214  (e.g., over a conductive loop signal path formed from segment  76 , conductive structures  156 , conductive layer  150 , conductive structures  154 , and segment  178 ). 
     Feeding near-field communications antenna  166  using differential signal pair S+/S− at antenna feed terminals  212  and  214  may generate electromagnetic hotspots on either side of gap  18 - 3 . If care is not taken, the differential signals in the differential signal pair (i.e., corresponding antenna currents) may arrive at antenna feed terminals  212  and  214  in phase with each other. Because antenna currents at antenna feed terminals  212  and  214  are conveyed in opposite directions (i.e., to the left and to the right of the page in  FIG. 6 , respectively), this may cause the magnetic fields associated with each differential signal to cancel out, reducing the strength of current I 2  and the overall antenna efficiency of near-field communications antenna  166 . In order to mitigate this cancellation, near-field communications transceiver circuitry  44  may include phase shifter circuitry that provides a phase shift to differential signals S+ and/or S− so that differential signal S+ at antenna feed terminal  212  is out of phase with respect to differential signal S− at antenna feed terminal  214  (e.g., 180 degrees out of phase or another angle between 150 degrees and 210 out of phase). Providing differential signals S+ and S− out of phase with each other in this manner may minimize magnetic field cancellations in the vicinity of gap  18 - 3 , thereby maximizing antenna efficiency for near-field communications antenna  166 . This may maximize the strength of antenna current I 2  across the entire conductive loop path of near-field communications antenna  166  (e.g., so that near-field communications antenna  166  may reliably communicate with an external device such as an RFID reader held towards any part of near-field communications antenna  166 ). 
     The example of  FIG. 6  in which phase shifter circuitry is formed within near-field communications transceiver circuitry  44  is merely illustrative. If desired, phase shifter circuitry may be interposed on transmission line  110 D external to near-field communications transceiver circuitry  44 . 
       FIG. 7  is a diagram showing how phase shifter circuitry may be interposed on transmission line  110 D external to near-field communications transceiver circuitry  44 . As shown in  FIG. 7 , near-field communications transceiver circuitry  44  may be mounted to substrate  152 . Near-field communications transceiver circuitry  44  may be coupled to conductive path  110 D using balun  246 . Differential signal terminals  210  and  206  of near-field communications transceiver circuitry  44  may be coupled to balun  246 . 
     Balun  246  may contain coupled inductors  245  and  247 . Inductors  245  and  247  may be coupled by near-field electromagnetic coupling (i.e., inductors  245  and  247  form a transformer and are magnetically coupled). Inductor  245  may have a first terminal coupled to terminal  210  of near-field communications transceiver circuitry  44  and may have a second terminal coupled to terminal  206  of near-field communications transceiver circuitry  44 . Inductor  247  may have a first terminal such as terminal  242  that is coupled to ground. Inductor  247  may also have a second terminal that is coupled to conductor  250  of conductive path  110 D. 
     During operation of near-field communications transceiver circuitry  44 , differential signals may be provided across terminals  210  and  206 . Balun  246  serves as a differential-to-single-ended converter that converts differential signal pair S+/S− appearing across differential terminals  210  and  206  to single-ended signals S at conductor  250  of conductive path  110 D. 
     Conductor  250  be coupled to node  259 . Node  259  may be coupled to conductor  262  and conductor  252  (e.g., conductor  250  may branch into two separate paths at node  259 ). A first phase shifting circuit such as phase shifter  258  may be interposed on conductor  254 . A second phase shifting circuit such as phase shifter  260  may be interposed on conductor  252 . Single-ended signals S may be provided to both phase shifters  258  and  260 . Phase shifter  258  may apply a first phase shift to single-ended signal S and may output the phase-shifted signal to antenna feed terminal  212  on near-field communications antenna  166  ( FIG. 6 ). Phase shifter  260  may apply a second phase shift to single-ended signal S and may output the phase-shifted signal to antenna feed terminal  214  on near-field communications antenna  166 . 
     The first and second phase shifts may have any desired value (e.g., where the signals at antenna feed terminal  212  are approximately 180 degrees out of phase with the signals at antenna feed terminal  214 ). As one example, phase shifter  258  may apply a −90 degree phase shift whereas phase shifter  260  applies a +90 degree phase shift. This example is merely illustrative and, in general, any desired phase shifts may be used. One of phase shifters  258  and  260  may be omitted if desired. 
     As shown in  FIG. 7 , conductor  250 , conductor  254 , conductor  252 , phase shifters  258 , and phase shifter  260  may be formed on a shared substrate such as flexible printed circuit  256 . For example, conductor  254  and phase shifter  258  may be formed on a first branch  262  of flexible printed circuit  256  whereas conductor  252  and phase shifter  260  are formed on a second branch  264  of flexible printed circuit  256 . One or more of these components may be formed on a different substrate if desired. In another suitable arrangement, one or more of these components (e.g., all of these components) may be formed on the same substrate  152  as near-field communications transceiver circuitry  44 . Balun  246  is formed external to near-field communications transceiver circuitry  44 . Balun  246  may be formed on substrate  152  (as shown in  FIG. 7 ), may be formed on flexible printed circuit  256 , or may be formed on a separate substrate if desired. Forming phase shifters  258  and  260  external to near-field communications transceiver circuitry  44  in this way may, for example, simplify manufacturing cost and complexity for near-field communications transceiver circuitry  44 . 
     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: 20180220
Publication Date: 20190129
Grant Date: 20190129
Priority Date: 20180220
Inventors: Garrido Lopez, David
AZAD, Umar
RAJAGOPALAN, HARISH
ATMATZAKIS, GEORGIOS
GOMEZ ANGULO, RODNEY A.
PASCOLINI, MATTIA
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q1/50", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/44", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/38", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q7/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/48", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/36", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/0006", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W88/02", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04B7/0413", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04B1/38", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/0081", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B7/0413", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W88/02", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04B1/38", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/263", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04B5/263", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01Q1/22", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B5/26", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B5/70", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/24", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/24", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/70", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/72", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 65032221