PATENT DOCUMENT

Publication Number: US-11228345-B1
Application Number: US-202017028877-A
Country: US
Kind Code: B1

Title: Electronic devices having differential-fed near-field communications antennas

Abstract:
A device with near-field communications (NFC) capabilities is provided. A housing may include first and second segments and a support plate separated from the segments by a slot. A first inductor may be coupled between the first segment and the plate. A second inductor may be coupled between the second segment and the plate. A transceiver may have a first signal terminal coupled to the first segment over a first path and a second signal terminal coupled to the second segment over a second path. The transceiver may convey differential signals in an NFC band over a loop path for an NFC antenna that includes the first conductive path, the first segment, the first inductor, a portion of the plate between the first and second inductors, the second inductor, the second segment, and the second conductive path. This may optimize wireless performance and volume for the NFC antenna.

Claims:
What is claimed is: 
     
       1. An electronic device comprising:
 a housing having peripheral conductive structures; 
 first, second, and third dielectric-filled gaps in the peripheral conductive structures, wherein the first dielectric-filled gap separates first and second segments of the peripheral conductive structures, the second dielectric-filled gap separates the second segment from a third segment of the peripheral conductive structures, and the third dielectric-filled gap separates the third segment from a fourth segment of the peripheral conductive structures; 
 a conductive support plate coupled to the first and fourth segments, wherein the conductive support plate is separated from the second and third segments by a slot; 
 a first inductor coupled across the slot, wherein the first inductor has a first terminal coupled to the second segment and a second terminal coupled to the conductive support plate; 
 a second inductor coupled across the slot, wherein the second inductor has a third terminal coupled to the third segment and a fourth terminal coupled to the conductive support plate; and 
 near-field communications (NFC) transceiver circuitry coupled to the second and third segments and configured to convey NFC signals over a conductive loop path that includes a portion of the second segment, the first inductor, a portion of the conductive support plate extending between the second and fourth terminals, the second inductor, and a portion of the third segment. 
 
     
     
       2. The electronic device of  claim 1 , further comprising:
 a first conductive path that couples a first signal terminal of the NFC transceiver circuitry to the second segment; and 
 a second conductive path that couples a second signal terminal of the NFC transceiver circuitry to the third segment. 
 
     
     
       3. The electronic device of  claim 2 , further comprising:
 a third inductor interposed on the first conductive path; and 
 a fourth inductor interposed on the second conductive path. 
 
     
     
       4. The electronic device of  claim 3 , wherein the NFC signals comprise differential signals and the first and second signal terminals form a differential feed for the conductive loop path. 
     
     
       5. The electronic device of  claim 3 , further comprising:
 a flexible printed circuit, wherein a portion of the first conductive path, a portion of the second conductive path, the third inductor, and the fourth inductor are formed on the flexible printed circuit. 
 
     
     
       6. The electronic device of  claim 5 , further comprising:
 a logic board, wherein the NFC transceiver circuitry is mounted to the logic board; and 
 impedance matching circuitry on the logic board, wherein the matching circuitry is interposed on the first and second conductive paths. 
 
     
     
       7. The electronic device of  claim 6 , further comprising:
 a first impedance matching circuit on the flexible printed circuit and interposed on the first conductive path between the third inductor and the impedance matching circuitry; and 
 a second impedance matching circuit on the flexible printed circuit and interposed on the second conductive path between the fourth inductor and the impedance matching circuitry. 
 
     
     
       8. The electronic device of  claim 1 , further comprising:
 a far-field antenna feed coupled between a first point on the second segment and the conductive support plate, wherein the NFC transceiver circuitry is coupled to a second point on the second segment and to a third point on the third segment, the second point is interposed on the second segment between the first point and the first dielectric-filled gap, the first point is interposed on the second segment between the second point and first terminal of the first inductor, and the third terminal of the second inductor is interposed on the third segment between the second dielectric-filled gap and the third point. 
 
     
     
       9. The electronic device of  claim 8 , wherein the second segment comprises a knuckle at the second dielectric-filled gap, the first terminal of the first inductor being interposed on the second segment between the first point and the knuckle. 
     
     
       10. The electronic device of  claim 8 , wherein the second segment comprises a knuckle at the second dielectric-filled gap, the first terminal of the first inductor being coupled to the knuckle. 
     
     
       11. The electronic device of  claim 10 , wherein the far-field antenna feed is configured to convey radio-frequency signals in a far-field frequency band, the second segment is configured to radiate the radio-frequency signals in the far-field frequency band, and the electronic device further comprises:
 an antenna tuning component coupled between a fourth point on the second segment and the conductive support plate, wherein the antenna tuning component is configured to tune a frequency response of the second segment in the far-field frequency band, the fourth point being interposed on the second segment between the first point and the knuckle. 
 
     
     
       12. The electronic device of  claim 8 , wherein the third terminal of the second inductor is coupled to the third segment at the second dielectric-filled gap. 
     
     
       13. The electronic device of  claim 12 , further comprising:
 an additional far-field antenna feed coupled between a fourth point on the third segment and the conductive support plate, wherein fourth point is interposed on the second segment between the third point and the third terminal of the second inductor. 
 
     
     
       14. 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 second dielectric-filled gaps and a second segment of the peripheral conductive structures extends between the second and third dielectric-filled gaps; 
 an antenna ground, wherein the first dielectric-filled gap separates the first segment from the antenna ground and the third dielectric-filled gap separates the second segment from the antenna ground; 
 a first far-field antenna feed coupled to a first point on the first segment; 
 a second far-field antenna feed coupled to a second point on the second segment; and 
 near-field communications (NFC) transceiver circuitry having a differential signal feed coupled to a third point on the first segment and a fourth point on the second segment, wherein the third point is interposed on the first segment between the first point and the first dielectric-filled gap, the fourth point is interposed on the second segment between the second point and the third dielectric-filled gap, and the NFC transceiver circuitry is configured to convey differential signals in an NFC frequency band using a conductive loop path that includes a portion of the first segment, a portion of the second segment, and a portion of the antenna ground. 
 
     
     
       15. The electronic device of  claim 14 , wherein the conductive loop path comprises:
 a first inductor coupled between the first segment and the antenna ground; and 
 a second inductor coupled between the second segment and the antenna ground, wherein the portion of the antenna ground extends from the first inductor to the second inductor, the first and second segments are configured to radiate in at least one far-field frequency band, and the first and second inductors are configured to block radio-frequency signals in the at least one far-field frequency band. 
 
     
     
       16. The electronic device of  claim 15 , further comprising:
 an antenna tuning component coupled between the first segment and the antenna ground, wherein the antenna tuning component is configured to tune a frequency response of the first segment in the at least one far-field frequency band and is configured to perform impedance matching for the NFC transceiver circuitry in the NFC frequency band. 
 
     
     
       17. The electronic device of  claim 15 , wherein the first inductor is coupled to a fifth point on the first segment, the second inductor is coupled to a sixth point on the second segment, the first point is interposed on the first segment between the fifth point and the third point, and the second point is interposed on the second segment between the sixth point and the fourth point. 
     
     
       18. An electronic device comprising:
 a conductive housing wall having a dielectric-filled gap that divides the conductive housing wall into first and second segments; 
 a logic board; 
 a flexible printed circuit coupled to the logic board and the first and second segments; 
 NFC transceiver circuitry mounted to the logic board, wherein the NFC transceiver circuitry has first and second differential signal terminals and is configured to convey differential signals in an NFC frequency band over the first and second differential signal terminals; 
 a first conductive path on the logic board and the flexible printed circuit, wherein the first conductive path couples the first differential signal terminal to the first segment; 
 a second conductive path on the logic board and the flexible printed circuit, wherein the second conductive path couples the second differential signal terminal to the second segment; and 
 impedance matching circuitry on the logic board and interposed on the first and second conductive paths, wherein the impedance matching circuitry is configured to match an impedance of the NFC transceiver circuitry to an impedance of the first and second segments. 
 
     
     
       19. The electronic device of  claim 18 , further comprising:
 a first impedance matching circuit on the flexible printed circuit and interposed on the first conductive path between the impedance matching circuitry and the first segment; and 
 a second impedance matching circuit on the flexible printed circuit and interposed on the second conductive path between the impedance matching circuitry and the second segment, wherein the first and second impedance matching circuits are configured to match the impedance of the NFC transceiver circuitry to the impedance of the first and second segments. 
 
     
     
       20. The electronic device of  claim 18 , further comprising:
 an antenna ground; 
 a first inductor coupled between the first segment and the antenna ground; and 
 a second inductor coupled between the second segment and the antenna ground, wherein a portion of the first segment, the first inductor, a portion of the antenna ground extending between the first and second inductors, the second inductor, and a portion of the second segment form part of an NFC loop antenna resonating element.

Description:
BACKGROUND 
     This relates generally to electronic devices and, more particularly, to electronic devices with wireless communications capabilities. 
     Electronic devices with wireless communications capabilities include wireless circuitry with one or more antennas. To satisfy consumer demand for small form factor electronic devices, manufacturers are continually striving to implement wireless circuitry such as antenna components using compact structures. At the same time, 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 also covering additional non-near-field (far-field) bands. Because antennas have the potential to interfere with each other and with other components in a wireless device, it can be difficult to provide wireless circuitry that handles both near-field and non-near-field communications bands with satisfactory levels of wireless performance. 
     It would therefore be desirable to be able to provide improved wireless circuitry for electronic devices. 
     SUMMARY 
     An electronic device may be provided with wireless circuitry and a housing having peripheral conductive housing structures and a conductive support plate. 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 housing structures may divide the structures into first and second segments. The conductive support plate may be separated from the first and second segments by a slot. A first inductor may be coupled between a first terminal on the first segment and a second terminal on the conductive support plate. A second inductor may be coupled between a third terminal on the second segment and a fourth terminal on the conductive support plate. A portion of the conductive support plate may extend from the second terminal to the fourth terminal. Far-field antenna feeds may be coupled to the first and second segments at locations between the first and third terminals, respectively, and additional dielectric-filled gaps in the peripheral conductive housing structures. 
     The NFC transceiver circuitry may have first and second differential signal terminals. The first differential signal terminal may be coupled to the first segment over a first conductive path. The second differential signal terminal may be coupled to the second segment over a second conductive path. Additional inductors may be interposed on the first and second conductive paths. The NFC transceiver circuitry may convey differential signals in an NFC band over a conductive loop path for an NFC antenna in the device. The conductive loop path may include at least a portion of the first conductive path, at least a portion of the first segment, the first inductor, the portion of the conductive support plate, the second inductor, at least a portion of the second segment, and at least a portion of the second conductive path. This may serve to optimize the wireless performance of the NFC antenna while also maximizing the volume of the NFC antenna. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative electronic device in accordance with some embodiments. 
         FIG. 2  is a schematic diagram of illustrative circuitry in an electronic device in accordance with some embodiments. 
         FIG. 3  is a schematic diagram of illustrative wireless circuitry in accordance with some embodiments. 
         FIG. 4  is a cross-sectional side view of an electronic device having housing structures that may be used in forming antenna structures in accordance with some embodiments. 
         FIG. 5  is a top view of an illustrative electronic device having a differential-fed near-field communications antenna formed at least in part from non-near-field antenna structures in accordance with some embodiments. 
         FIG. 6  is a top view of an illustrative differential-fed near-field communications antenna having an inductor coupled between an end of an antenna resonating element arm for a non-near-field-communications antenna and a conductive support plate in accordance with some embodiments. 
         FIG. 7  is a schematic diagram showing how illustrative impedance matching circuitry may be coupled between near-field communications transceiver circuitry and a near-field communications antenna in accordance with some embodiments. 
         FIG. 8  is a schematic diagram showing how illustrative impedance matching circuitry for a near-field communications antenna may be distributed between a main logic board and flexible printed circuit structures in accordance with some embodiments. 
         FIG. 9  is a circuit diagram of an illustrative antenna tuning component for a non-near-field communications antenna that also performs impedance matching for a near-field communications antenna in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices such as 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. For example, the wireless communications circuitry may be used to support wireless communications in near-field communications (NFC) and non-near-field communications (non-NFC) bands. 
     Device  10  may be a portable electronic device or other suitable electronic device. For example, 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, headset 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, a 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 (e.g., a dielectric cover layer). 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 materials. 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. Conductive portions of peripheral structures  12 W and conductive portions of 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). In other words, device  10  may have a length (e.g., measured parallel to the Y-axis), a width that is less than the length (e.g., measured parallel to the X-axis), and a height (e.g., measured parallel to the Z-axis) that is less than the width. 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 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, alloys, 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 ledge 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 ). 
     Rear housing wall  12 R may lie in a plane that is parallel to display  14 . In configurations for device  10  in which some or all of 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 rear housing wall  12 R. For example, rear housing wall  12 R of device  10  may include 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 . 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 conductive portions of 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/cover 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 peripheral conductive housing structures  12 W and/or conductive portions of rear housing wall  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 of display  14  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 overlap inactive area IA may be coated with an opaque masking layer in inactive area IA. The opaque masking layer may have any suitable color. Inactive area IA may include a recessed region such as notch  8  that extends into active area AA. Active area AA may, for example, be defined by the lateral area of a display module for display  14  (e.g., a display module that includes pixel circuitry, touch sensor circuitry, etc.). The display module may have a recess or notch in upper region  20  of device  10  that is free from active display circuitry (i.e., that forms notch  8  of inactive area IA). Notch  8  may be a substantially rectangular region that is surrounded (defined) on three sides by active area AA and on a fourth side by peripheral conductive housing structures  12 W. 
     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  16  in notch  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 conductive support plate or backplate) that spans the walls of housing  12  (e.g., a substantially rectangular sheet formed from one or more metal parts that is welded or otherwise connected between opposing sides of peripheral conductive housing structures  12 W). The conductive support plate may form an exterior rear surface of device  10  or may be covered by a dielectric cover layer such as a thin cosmetic layer, protective coating, 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 conductive support plate from view of the user (e.g., the conductive support plate may form part of rear housing wall  12 R). 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 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  22  and  20  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  22  and  20 . 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  22  and  20 ), thereby narrowing the slots in regions  22  and  20 . Region  22  may sometimes be referred to herein as lower region  22  or lower end  22  of device  10 . Region  20  may sometimes be referred to herein as upper region  20  or upper end  20  of device  10 . 
     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 lower region  22  and/or upper region  20  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. The conductive segments that are formed in this way may form parts of antennas in device  10  if desired. Other dielectric openings may be formed in peripheral conductive housing structures  12 W (e.g., dielectric openings other than gaps  18 ) and may serve as dielectric antenna windows for antennas mounted within the interior of device  10 . Antennas within device  10  may be aligned with the dielectric antenna windows for conveying radio-frequency signals through peripheral conductive housing structures  12 W. Antennas within device  10  may also be aligned with inactive area IA of display  14  for conveying radio-frequency signals through display  14 . 
     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 behind display  14  that is available for antennas within device  10 . For example, active area AA of display  14  may include conductive structures that serve to block radio-frequency signals handled by antennas mounted behind active area AA from radiating through the front face of device  10 . 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 communicate with wireless equipment external to device  10  with satisfactory efficiency bandwidth. 
     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 in upper region  20  of device  10 . A lower antenna may, for example, be formed in lower region  22  of device  10 . Additional antennas may be formed along the edges of housing  12  extending between regions  20  and  22  if desired. 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. Other antennas for covering any other desired frequencies may also be mounted at any desired locations within the interior of device  10 . The example of  FIG. 1  is merely illustrative. If desired, housing  12  may have other shapes (e.g., a square shape, cylindrical shape, spherical shape, combinations of these and/or different shapes, etc.). 
     A schematic diagram of illustrative components that may be used in device  10  is shown in  FIG. 2 . As shown in  FIG. 2 , device  10  may include control circuitry  28 . Control circuitry  28  may include storage such as storage circuitry  30 . Storage circuitry  30  may include hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid-state drive), volatile memory (e.g., static or dynamic random-access-memory), etc. 
     Control circuitry  28  may include processing circuitry such as processing circuitry  32 . 
     Processing circuitry  32  may be used to control the operation of device  10 . Processing circuitry  32  may include on one or more microprocessors, microcontrollers, digital signal processors, host processors, baseband processor integrated circuits, application specific integrated circuits, central processing units (CPUs), etc. Control circuitry  28  may be configured to perform operations in device  10  using hardware (e.g., dedicated hardware or circuitry), firmware, and/or software. Software code for performing operations in device  10  may be stored on storage circuitry  30  (e.g., storage circuitry  30  may include non-transitory (tangible) computer readable storage media that stores the software code). The software code may sometimes be referred to as program instructions, software, data, instructions, or code. Software code stored on storage circuitry  30  may be executed by processing circuitry  32 . 
     Control 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, control circuitry  28  may be used in implementing communications protocols. Communications protocols that may be implemented using control circuitry  28  include internet protocols, wireless local area network protocols (e.g., IEEE 802.11 protocols—sometimes referred to as WiFi®), protocols for other short-range wireless communications links such as the Bluetooth® protocol or other WPAN protocols, IEEE 802.11ad protocols, cellular telephone protocols, MIMO protocols, antenna diversity protocols, satellite navigation system protocols, antenna-based spatial ranging protocols (e.g., radio detection and ranging (RADAR) protocols or other desired range detection protocols for signals conveyed at millimeter and centimeter wave frequencies), etc. Each communication protocol may be associated with a corresponding radio access technology (RAT) that specifies the physical connection methodology used in implementing the protocol. 
     Device  10  may include input-output circuitry  24 . Input-output circuitry  24  may include input-output devices  26 . Input-output devices  26  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  26  may include user interface devices, data port devices, sensors, and other input-output components. For example, input-output devices may include touch screens, displays without touch sensor capabilities, buttons, joysticks, scrolling wheels, touch pads, key pads, keyboards, microphones, cameras, speakers, status indicators, light sources, audio jacks and other audio port components, digital data port devices, light sensors, gyroscopes, accelerometers or other components that can detect motion and device orientation relative to the Earth, capacitance sensors, proximity sensors (e.g., a capacitive proximity sensor and/or an infrared proximity sensor), magnetic sensors, and other sensors and input-output components. 
     Input-output circuitry  24  may include wireless circuitry such as wireless circuitry  34  for wirelessly conveying radio-frequency signals. While control circuitry  28  is shown separately from wireless circuitry  34  in the example of  FIG. 2  for the sake of clarity, wireless circuitry  34  may include processing circuitry that forms a part of processing circuitry  32  and/or storage circuitry that forms a part of storage circuitry  30  of control circuitry  28  (e.g., portions of control circuitry  28  may be implemented on wireless circuitry  34 ). As an example, control circuitry  28  may include baseband processor circuitry or other control components that form a part of wireless circuitry  34 . 
     Wireless circuitry  34  may include non-near-field communications (non-NFC) transceiver circuitry  36  (sometimes referred to herein as far-field transceiver circuitry  36 ). Non-NFC transceiver circuitry  36  may include transceiver circuitry for handling non-NFC communications (e.g., far-field communications using radio-frequency signals conveyed in non-NFC frequency bands). Frequency bands may sometimes be referred to herein as communications bands or simply as “bands” and may span corresponding ranges of frequencies. 
     The transceiver circuitry in non-NFC transceiver circuitry  36  may include, for example, wireless local area network (WLAN) transceiver circuitry that handles 2.4 GHz and 5 GHz bands for Wi-Fi® (IEEE 802.11) communications, wireless personal area network (WPAN) transceiver circuitry that handles the 2.4 GHz Bluetooth® communications band, cellular telephone transceiver circuitry that handles cellular telephone bands (e.g., bands from about 600 MHz to about 5 GHz, 3G bands, 4G LTE bands, 5G New Radio Frequency Range 1 (FR1) bands below 10 GHz, 5G New Radio Frequency Range 2 (FR2) bands between 20 and 60 GHz, etc.), satellite navigation receiver circuitry that handles satellite navigation bands (e.g., a GPS band from 1565 to 1610 MHz, a Global Navigation Satellite System (GLONASS) band, a BeiDou Navigation Satellite System (BDS) band, etc.), ultra-wideband (UWB) transceiver circuitry that handles communications using the IEEE 802.15.4 protocol and/or other ultra-wideband communications protocols, and/or any other desired radio-frequency transceiver circuitry for covering any other desired non-NFC bands of interest. The radio-frequency signals handled by non-NFC transceiver circuitry  36  may propagate in the electromagnetic far-field domain (e.g., over a distance of several feet, several meters, tens of meters, hundreds of meters, thousands of meters, miles, hundreds of miles, etc.). The radio-frequency signals handled by non-NFC transceiver circuitry  36  may sometimes be referred to herein as non-NFC signals or far-field signals. 
     Wireless circuitry  34  may also include near-field communications (NFC) transceiver circuitry  38  (sometimes referred to herein as NFC circuitry  38 , NFC transceiver circuits  38 , NFC transceiver  38 , near-field circuitry  38 , near-field transceiver circuitry  38 , or near-field transceiver  38 ). NFC transceiver circuitry  38  may generate and/or receive radio-frequency signals in an NFC frequency band (e.g., at 13.56 MHz). These radio-frequency signals may sometimes be referred to herein as NFC signals. 
     The NFC signals may be used to support communications between device  10  and an NFC reader or other external NFC equipment. The NFC signals handled by NFC transceiver circuitry  38  may propagate in the electromagnetic near-field domain (e.g., via electromagnetic near-field coupling over a distance of less than a foot, 20 cm or less, etc.). Near-field communications may, for example, 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 an overlapping or adjacent NFC reader). NFC links typically are formed over distances of 20 cm or less (e.g., device  10  must be placed in the vicinity of the near-field communications reader for effective communications). 
     Non-NFC transceiver circuitry  36  and NFC transceiver circuitry  38  may each include one or more integrated circuits (chips), integrated circuit packages (e.g., multiple integrated circuits mounted on a common printed circuit in a system-in-package device, one or more integrated circuits mounted on different substrates, etc.), power amplifier circuitry, up-conversion circuitry, down-conversion circuitry, low-noise input amplifiers, passive radio-frequency components, switching circuitry, transmission line structures, and other circuitry for handling radio-frequency signals and/or for converting signals between radio-frequencies, intermediate frequencies, and/or baseband frequencies. Non-NFC transceiver circuitry  36  may be omitted if desired. 
     As shown in  FIG. 2 , wireless circuitry  34  may include antennas  40 . Non-NFC transceiver circuitry  36  may convey non-NFC signals at frequencies greater than 100 MHz using one or more antennas  40 . NFC transceiver circuitry  38  may convey NFC signals below 100 MHz (e.g., in an NFC frequency band at 13.56 MHz) using one or more antennas  40 . In general, transceiver circuitry  36  and  38  may be configured to cover (handle) any suitable communications (frequency) bands of interest. The transceiver circuitry may convey radio-frequency signals using antennas  40  (e.g., antennas  40  may convey the radio-frequency signals for the transceiver circuitry). The term “convey radio-frequency signals” as used herein means the transmission and/or reception of the radio-frequency signals (e.g., for performing unidirectional and/or bidirectional wireless communications with external wireless communications equipment). Antennas  40  may transmit the radio-frequency signals by radiating the radio-frequency signals into free space (or to freespace through intervening device structures such as a dielectric cover layer). Antennas  40  may additionally or alternatively receive the radio-frequency signals from free space (e.g., through intervening devices structures such as a dielectric cover layer). The transmission and reception of radio-frequency signals by antennas  40  each involve the excitation or resonance of antenna currents on an antenna resonating element in the antenna by the radio-frequency signals within the frequency band(s) of operation of the antenna. 
     Antennas  40  in wireless circuitry  34  may be formed using any suitable antenna types. For example, antennas  40  may include antennas with resonating elements that are formed from stacked patch antenna structures, loop antenna structures, patch antenna structures, inverted-F antenna structures, slot antenna structures, planar inverted-F antenna structures, waveguide structures, monopole antenna structures, dipole antenna structures, helical antenna structures, Yagi (Yagi-Uda) antenna structures, hybrids of these designs, etc. In another suitable arrangement, antennas  40  may include antennas with dielectric resonating elements such as dielectric resonator antennas. If desired, one or more of antennas  40  may be cavity-backed antennas. Two or more antennas  40  may be arranged in a phased antenna array if desired (e.g., for conveying centimeter and/or millimeter wave signals). Different types of antennas may be used for different bands and combinations of bands. Antennas  40  that are used to convey non-NFC signals may sometimes be referred to herein as non-NFC antennas or far-field antennas. Antennas  40  that are used to convey NFC signals may sometimes be referred to herein as NFC antennas. 
     In one suitable arrangement that is sometimes described herein as an example, antennas  40  may include an NFC antenna that includes a conductive loop path (e.g., a conductive loop path that forms a loop antenna resonating element that is used to convey NFC signals for NFC transceiver circuitry  38 ). The conductive loop path may run through the antenna resonating element of one or more of the non-NFC antennas that are used to convey non-NFC signals for non-NFC transceiver circuitry  36  (e.g., the loop antenna resonating element for the NFC antenna may include portions of the antenna resonating element of one or more non-NFC antennas). 
       FIG. 3  is a schematic diagram showing how a given antenna  40  may be fed by corresponding transceiver circuitry. As shown in  FIG. 3 , antenna  40  may be coupled to transceiver circuitry  42  (e.g., transceiver circuitry such as NFC transceiver circuitry  38  or non-NFC transceiver circuitry  36  of  FIG. 2 ). Transceiver circuitry  42  may be coupled to antenna feed  50  of antenna  40  using a transmission line path that includes radio-frequency transmission line  44 . Radio-frequency transmission line  44  may include a first signal conductor such as signal conductor  46  (e.g., a positive signal conductor) and may include a second signal conductor such as signal conductor  48  (e.g., a ground signal conductor). Conductor  48  may, for example, be coupled to the antenna ground for antenna  40  (e.g., over a ground antenna feed terminal of antenna feed  50  located at the antenna ground). Conductor  46  may, for example, be coupled to the antenna resonating element for antenna  40  (e.g., over a positive antenna feed terminal of antenna feed  50  located at the antenna resonating element). 
     In scenarios where antenna  40  is used to convey NFC signals, antenna  40  may sometimes be referred to herein as NFC antenna  40 NFC. In some scenarios, the NFC antenna is fed single-ended NFC signals using a single-ended radio-frequency transmission line (e.g., antenna feed  50  may be a single-ended antenna feed). In one suitable arrangement that is described herein as an example, the NFC antenna is fed differential NFC signals using a differential radio-frequency transmission line (e.g., antenna feed  50  may be a differential antenna feed having differential antenna feed terminals and the NFC antenna may be a differential-fed NFC antenna). 
     Radio-frequency transmission line  44  may include a stripline transmission line (sometimes referred to herein simply as a stripline), a coaxial cable, a coaxial probe realized by metalized vias, a microstrip transmission line, an edge-coupled microstrip transmission line, an edge-coupled stripline transmission lines, a waveguide structure, combinations of these, etc. Multiple types of transmission lines may be used to form the transmission line path that couples transceiver circuitry  42  to antenna feed  50 . Filter circuitry, switching circuitry, impedance matching circuitry, phase shifter circuitry, balun circuitry, amplifier circuitry, and/or other circuitry may be interposed on radio-frequency transmission line  44 , if desired. 
     Radio-frequency transmission lines in device  10  may be integrated into ceramic substrates, rigid printed circuit boards, and/or flexible printed circuits. In one suitable arrangement, radio-frequency transmission lines in device  10  may be 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). 
     If desired, conductive electronic device structures such as conductive portions of housing  12  ( FIG. 1 ) may be used to form part of one or more of the antennas  40  in device  10 .  FIG. 4  is a cross-sectional side view of upper region  20  of device  10 , showing illustrative conductive electronic device structures that may be used in forming one or more of the antennas  40  in device  10 . 
     As shown in  FIG. 4 , peripheral conductive housing structures  12 W may extend around the lateral periphery of device  10  (e.g., as measured in the X-Y plane) and may extend from rear housing wall  12 R (e.g., at the rear face of device  10 ) to display  14  (e.g., at the front face of device  10 ). In other words, peripheral conductive housing structures  12 W may form conductive sidewalls for device  10 , a first of which is shown in the cross-sectional side view of  FIG. 4  (e.g., a top sidewall that runs along the top edge of device  10  and that extends across the width of device  10  within upper region  20 , as shown in  FIG. 1 ). 
     Display  14  may have a display module such as display module  54  (sometimes referred to as a display panel). Display module  54  may include pixel circuitry, touch sensor circuitry, force sensor circuitry, and/or any other desired circuitry for forming active area AA of display  14 . Display  14  may include a dielectric cover layer such as display cover layer  52  that overlaps display module  54 . Display cover layer  52  may include plastic, glass, sapphire, ceramic, and/or any other desired dielectric materials. Display module  54  may emit image light and may receive sensor input (e.g., touch and/or force sensor input) through display cover layer  52 . Display cover layer  52  and display  14  may be mounted to peripheral conductive housing structures  12 W. The lateral area of display  14  that does not overlap display module  54  may form inactive area IA of display  14 . 
     As shown in  FIG. 4 , rear housing wall  12 R may be mounted to peripheral conductive housing structures  12 W (e.g., opposite display  14 ). Rear housing wall  12 R may include a conductive layer such as conductive support plate  58 . Conductive support plate  58  may extend across an entirety of the width of device  10  (e.g., between the left and right edges of device  10  as shown in  FIG. 1  and parallel to the X-axis of  FIG. 4 ). Conductive support plate  58  may have an edge  59  that is separated from peripheral conductive housing structures  12 W by dielectric-filled slot  60  (sometimes referred to herein as opening  60 , gap  60 , or aperture  60 ). Slot  60  may be filled with air, plastic, ceramic, or other dielectric materials. Conductive support plate  58  may, if desired, provide structural and mechanical support for device  10 . 
     If desired, rear housing wall  12 R may include a dielectric cover layer such as dielectric cover layer  56 . Dielectric cover layer  56  may include glass, plastic, sapphire, ceramic, one or more dielectric coatings, or other dielectric materials. Dielectric cover layer  56  may be layered under conductive support plate  58  (e.g., conductive support plate  58  may be coupled to an interior surface of dielectric cover layer  56 ). If desired, dielectric cover layer  56  may extend across an entirety of the width of device  10  and/or an entirety of the length of device  10  (e.g., between the upper and lower edges of device  10  as shown in  FIG. 1  and parallel to the Y-axis of  FIG. 4 ). Dielectric cover layer  56  may overlap slot  60 . If desired, dielectric cover layer  56  be provided with pigmentation and/or an opaque masking layer (e.g., an ink layer) that helps to hide the interior of device  10  from view. In another suitable arrangement, dielectric cover layer  56  may be omitted and slot  60  may be filled with a solid dielectric material. 
     Conductive housing structures such as conductive support plate  58  and/or peripheral conductive housing structures  12 W (e.g., the portion of peripheral conductive housing structures  12 W opposite conductive support plate  58  at slot  60 ) may be used to form antenna structures for one or more of the antennas  40  in device  10 . For example, conductive support plate  58  may be used to form the ground plane for one or more of the NFC antennas in device  10  and/or to form one or more edges of a slot antenna resonating element (e.g., a slot antenna resonating element formed from a portion of slot  60 ) for a non-NFC antenna. Peripheral conductive housing structures  12 W may form an antenna resonating element arm for one or more of the non-NFC antennas in device  10 . A portion of peripheral conductive housing structures  12 W and/or a portion of conductive support plate  58  (e.g., at edge  59  of slot  60 ) may form part of a conductive loop path used to form a loop antenna resonating element for an NFC antenna in device  10 . 
       FIG. 5  is a top interior view showing how upper region  20  of device  10  may include an NFC antenna and one or more non-NFC antennas. Display  14  has been removed from the view shown in  FIG. 5  for the sake of clarity. While  FIG. 5  illustrates antenna structures in upper region  20  of device  10 , the structures of  FIG. 5  may additionally or alternatively be formed in lower region  22  ( FIG. 1 ) or other portions of device  10 . 
     As shown in  FIG. 5 , peripheral conductive housing structures  12 W may include a first conductive sidewall at the left edge of device  10 , a second conductive sidewall at the top edge of device  10  (e.g., as shown in the cross-sectional side view of  FIG. 4 ), and a third conductive sidewall at the right edge of device  10 . Peripheral conductive housing structures  12 W may be segmented by dielectric-filled gaps  18  such as a first gap  18 - 1 , a second gap  18 - 2 , and a third gap  18 - 3 . 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. 
     Gap  18 - 1  may divide the first conductive sidewall to separate segment  82  of peripheral conductive housing structures  12 W from segment  78  of peripheral conductive housing structures  12 W. Gap  18 - 2  may divide the second conductive sidewall to separate segment  78  from segment  80  of peripheral conductive housing structures  12 W. Gap  18 - 3  may divide the third conductive sidewall to separate segment  80  from segment  84  of peripheral conductive housing structures  12 W. Segment  78  may form the top-left corner of device  10  and may be formed from the first and second conductive sidewalls of peripheral conductive housing structures  12 W. Segment  80  may form the top-right corner of device  10  and may be formed from the second and third conductive sidewalls of peripheral conductive housing structures  12 W. Segment  78  may include a gap support structure for (at) gap  18 - 2  such as knuckle  118 . Knuckle  118  may provide mechanical support to peripheral conductive housing structures  12 W at gap  18 - 2 , may help to secure dielectric material in place within slot  60 , and/or may be used to help hold electronic components in place within device  10 . 
     Conductive support plate  58  may extend between opposing sidewalls of peripheral conductive housing structures  12 W. For example, conductive support plate  58  may extend from segment  82  to segment  84  of peripheral conductive housing structures  12 W (e.g., across the width of device  10 ). Conductive support plate  58  may be welded or otherwise affixed to segments  82  and  84 . In another suitable arrangement, conductive support plate  58 , segment  84 , and segment  82  may be formed from a single, integral (continuous) piece of machined metal (e.g., in a unibody configuration). Conductive support plate  58  may include one or more openings such as opening  122 . Openings such as opening  122  may be used to accommodate other components in device  10 , may be used to reduce the cost or weight of device  10 , may be used to form antenna windows for other antennas mounted within device  10  (e.g., for radiating through rear housing wall  12 R of  FIG. 4 ), etc. 
     Edge  59  of conductive support plate  58  may be separated from segment  78  and segment  80  of peripheral conductive housing structures  12 W by slot  60 . Knuckle  118  at gap  18 - 2  may, for example, include conductive material from segment  78  that extends into and/or over slot  60 . If desired, slot  60  may include an extended portion  92  that is interposed between edge  59  of conductive support plate  58  and segment  82  of peripheral conductive housing structures  12 W. One or more antennas such as a one-dimensional phased antenna array for conveying millimeter and centimeter wave signals and a planar inverted-F antenna for conveying other signals may at least partially overlap slot  60  (not shown in  FIG. 5  for the sake of clarity). Slot  60  may be filled with air, plastic, glass, sapphire, epoxy, ceramic, or other dielectric material. Slot  60  may be continuous with gaps  18 - 1 ,  18 - 2 , and  18 - 3  in peripheral conductive housing structures  12 W if desired (e.g., a single piece of dielectric material may be used to fill both slot  60  and gaps  18 - 1 ,  18 - 2 , and  18 - 3 ). 
     As shown in  FIG. 5 , upper region  20  of device  10  may include at least a first non-NFC antenna  40 - 1 , a second non-NFC antenna  40 - 2 , and a third non-NFC antenna  40 - 3 . Non-NFC antennas  40 - 1 ,  40 - 2 , and  40 - 3  may include an antenna ground (sometimes referred to herein as antenna ground structures or an antenna ground plane) formed from conductive support plate  58  and segments  82  and  84  of peripheral conductive housing structures  12 W, as an example. Additional conductive components such as conductive housing structures, conductive structures from electronic components, printed circuit board traces, strips of conductor such as strips of wire or metal foil, conductive display components, and/or other conductive structures may also form part of the antenna ground. 
     Non-NFC transceiver (TX/RX) circuitry  36  may feed non-NFC signals for non-NFC antennas  40 - 1 ,  40 - 2 , and  40 - 3  over one or more respective radio-frequency transmission lines  116  (e.g., radio-frequency transmission lines such as radio-frequency transmission line  44  of  FIG. 4 ). Each non-NFC antenna may have a corresponding antenna feed  50  coupled to a respective radio-frequency transmission line  116  (e.g., non-NFC antenna  40 - 1  may include (far-field) antenna feed  50 - 1 , non-NFC antenna  40 - 2  may include (far-field) antenna feed  50 - 2 , and non-NFC antenna  40 - 3  may include (far-field) antenna feed  50 - 3 ). This example is merely illustrative and, if desired, each non-NFC antenna may include multiple antenna feeds or other feeding arrangements may be used. 
     As shown in  FIG. 5 , non-NFC antenna  40 - 1  may have an open slot antenna resonating element formed from extended portion  92  of slot  60 . Antenna feed  50 - 1  for non-NFC antenna  40 - 1  may be coupled to segment  82  of peripheral conductive housing structures  12 W and conductive support plate  58  (e.g., across extended portion  92  of slot  60 ). Corresponding antenna currents for non-NFC antenna  40 - 1  may flow around the perimeter of extended portion  92  of slot  60  (e.g., in one or more non-NFC frequency bands). If desired, one or more antenna tuning components (e.g., components having fixed and/or adjustable inductors, capacitors, resistors, filters, and/or switches coupled together in any desired arrangement) may be coupled across extended portion  92  of slot  60 . The frequency response of non-NFC antenna  40 - 1  may be determined by the length of the perimeter of extended portion  92  of slot  60 , one or more harmonic modes of extended portion  92 , contribution from one or more parasitic elements, and/or antenna tuning components coupled across extended portion  92  of slot  60 , for example. 
     Non-NFC antenna  40 - 2  may have an antenna resonating element arm (e.g., an inverted-F antenna resonating element arm) formed from segment  78  of peripheral conductive housing structures  12 W. Antenna feed  50 - 2  for non-NFC antenna  40 - 2  may be coupled to segment  78  and conductive support plate  58  (e.g., across slot  60 ). Corresponding antenna currents for non-NFC antenna  40 - 2  may flow along segment  78  (e.g., in one or more non-NFC frequency bands). Non-NFC antenna  40 - 2  may include one or more return paths coupled between segment  78  and the antenna ground (not shown in  FIG. 5  for the sake of clarity). The return paths may include corresponding antenna tuning components for adjusting the frequency response of non-NFC antenna  40 - 2  in one or more of the non-NFC frequency bands (sometimes referred to herein as far-field frequency bands). The frequency response of non-NFC antenna  40 - 2  may be determined by the length of the segment  78 , one or more resonant modes of slot  60 , harmonic modes of segment  78  and/or slot  60 , contribution from one or more parasitic elements, and/or antenna tuning components coupled across slot  60 , for example. 
     Non-NFC antenna  40 - 3  may have an antenna resonating element arm (e.g., an inverted-F antenna resonating element arm) formed from segment  80  of peripheral conductive housing structures  12 W. Antenna feed  50 - 3  for non-NFC antenna  40 - 3  may be coupled to segment  80  and conductive support plate  58  (e.g., across slot  60 ). Corresponding antenna currents for non-NFC antenna  40 - 3  may flow along segment  80  (e.g., in one or more non-NFC frequency bands). 
     Non-NFC antenna  40 - 3  may include one or more return paths coupled between segment  80  and the antenna ground (not shown in  FIG. 5  for the sake of clarity). The return paths may include corresponding antenna tuning components for adjusting the frequency response of non-NFC antenna  40 - 3  in one or more of the non-NFC frequency bands. The frequency response of non-NFC antenna  40 - 3  may be determined by the length of the segment  80 , one or more resonant modes of slot  60 , harmonic modes of segment  80  and/or slot  60 , contribution from one or more parasitic elements, and/or antenna tuning components coupled across slot  60 , for example. Antenna feeds  50 - 1 ,  50 - 2 , and  50 - 3  may sometimes be referred to herein as non-NFC antenna feeds or far-field antenna feeds. 
     When operating using a single non-NFC 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 circuitry  34  ( FIG. 2 ) 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 , two or more of non-NFC antennas  40 - 1 ,  40 - 2 , and  40 - 3 , and/or additional non-NFC antennas in device  10  may be operated using a multiple-input and multiple-output (MIMO) scheme in one or more of the non-NFC frequency bands. When operating using a MIMO scheme, two or more of the non-NFC antennas 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 some scenarios, to support near-field communications in device  10 , device  10  may include a dedicated NFC antenna. However, as space is at a premium in devices such as device  10 , forming a dedicated NFC antenna may occupy an excessive amount of space in device  10  that could otherwise be occupied by other device components. Space can be conserved by using portions of non-NFC antenna  40 - 2  and non-NFC antenna  40 - 3  to form part of an NFC antenna for device  10 . As an example, device  10  may include an NFC antenna  40 NFC that is formed from portions of segment  78 , segment  80 , and conductive support plate  58 . 
     As shown in  FIG. 5 , NFC antenna  40 NFC may include a conductive loop path  114  that conveys antenna current I in an NFC frequency band (e.g., for transmission and/or reception of corresponding NFC signals). Conductive loop path  114  form a loop antenna resonating element for NFC antenna  40 NFC. Conductive loop path  114  may include segment  78  and segment  80  of peripheral conductive housing structures  12 W. By sharing conductive antenna structures between both NFC antenna  40 NFC and non-NFC antennas  40 - 2  and  40 - 3 , duplicative conductive structures can be minimized and antenna volume can be conserved within device  10 . At the same time, conductive loop path  114  may extend across substantially all of the width of device  10  (e.g., across the lengths of both non-NFC antennas  40 - 2  and  40 - 3 ). This may, for example, facilitate the use of device  10  for a user who is using device  10  to communicate with external NFC equipment such as an NFC (e.g., RFID) reader (e.g., so that the user does not have to focus on precisely placing device  10  over the NFC reader so that the volume of NFC antenna  40 NFC is aligned with the NFC reader). 
     NFC transceiver circuitry  38  may transmit and/or receive NFC signals using NFC antenna  40 NFC. NFC transceiver circuitry  38  may be mounted to a dedicated substrate (e.g., a rigid printed circuit board or flexible printed circuit), may be mounted to the main logic board for device  10 , or may be mounted to flexible printed circuit structures  72 . Flexible printed circuit structures  72  may include a single flexible printed circuit or multiple flexible printed circuits coupled together (e.g., using a surface mount technology (SMT) process). 
     In order to optimize the wireless performance of NFC antenna  40 NFC, NFC transceiver circuitry  38  may feed NFC antenna  40 NFC using differential signals in an NFC frequency band. For example, as shown in  FIG. 5 , NFC transceiver circuitry  38  may have a differential output that includes signal terminals  62  and  66  (e.g., a pair of differential signal terminals). signal terminals  62  and  66  may, for example, form a differential pair of antenna feed terminals (sometimes referred to collectively herein as differential antenna feed  50 D) for NFC antenna  40 NFC. Signal terminal  62  (sometimes referred to herein as first differential antenna feed terminal  62 ) may be coupled to point  76  on segment  78  of peripheral conductive housing structures  12 W via conductive path  68 . Signal terminal  66  (sometimes referred to herein as second differential antenna feed terminal  66 ) may be coupled to point  102  on segment  80  of peripheral conductive housing structures  12 W via conductive path  70 . Conductive paths  68  and  70  may, for example, form a differential signal path (sometimes referred to herein as a differential signal transmission line). NFC transceiver circuitry  38  may be coupled to ground (e.g., conductive support plate  58 ) via ground terminal  64 . 
     During operation of NFC transceiver circuitry  38 , differential signals across signal terminals  62  and  66  are transmitted and/or received by conductive loop path  114  of NFC antenna  40 NFC (e.g., the loop antenna resonating element for NFC antenna  40 NFC). The differential signals may include a differential signal pair S+/S−. Differential signal S+ of the differential signal pair may be conveyed over signal terminal  62 , conductive path  68 , and point (terminal)  76  on segment  78  of peripheral conductive housing structures  12 W. Differential signal S− of the differential signal pair may be conveyed over signal terminal  66 , conductive path  70 , and point (terminal)  102  on segment  80  of peripheral conductive housing structures  12 W. Antenna currents I (e.g., loop currents) corresponding to the differential signals may flow between signal terminals  62  and  66  (e.g., over conductive loop path  114 ). 
     The conductive loop path  114  for antenna currents I may extend from signal terminal  62  to signal terminal  66  through conductive path  68 , conductive path  70 , and portions of non-NFC antennas  40 - 2  and  40 - 3 . For example, as shown in  FIG. 5 , conductive loop path  114  may include conductive path  68 , at least a portion of segment  78  of peripheral conductive housing structures  12 W, a conductive path coupled between segment  78  and conductive support plate  58  such as a conductive path that includes inductor  86 , a conductive path coupled between conductive support plate  58  and segment  80  of peripheral conductive housing structures  12 W (e.g., at gap  18 - 2 ) such as a conductive path that includes inductor  88 , a conductive path extending between inductors  86  and  88  such as conductive path  115 , at least a portion of segment  80  of peripheral conductive housing structures  12 W, and conductive path  70 . This may configure conductive loop path  114  to extend across an entirety of the width of device  10 . 
     Inductor  86  may have a first terminal  94  coupled to segment  78  at a location on segment  78  that is interposed between knuckle  118  and antenna feed  50 - 2  (e.g., terminal  94  may be interposed on segment  78  between antenna feed  50 - 2  and knuckle  118  whereas point  76  is interposed on segment  78  between antenna feed  50 - 2  and gap  18 - 1 ). Inductor  86  may have a second terminal  96  coupled to conductive support plate  58 . Antenna feed  50 - 2  may be coupled to segment  78  at a location that is interposed between point  76  and terminal  94 . Inductor  88  may have a first terminal  100  coupled to an end of segment  80  (e.g., at gap  18 - 2 ) and a second terminal  98  coupled to conductive support plate  58 . Antenna feed  50 - 3  may be coupled to segment  80  at a location that is interposed between point  102  and terminal  100  (e.g., terminal  100  may be interposed on segment  80  between antenna feed  50 - 3  and gap  18 - 2  whereas point  102  is interposed on segment  80  between antenna feed  50 - 3  and gap  18 - 3 ). Conductive path  115  may extend from terminal  96  to terminal  98  and may form a portion of conductive loop path  114 . Conductive path  115  may be formed from the portion of conductive support plate  58  extending between terminals  96  and  98  (e.g., at edge  59 ) and/or may include conductive traces on a substrate such as flexible printed circuit  108 . Flexible printed circuit  108  may be formed as a part of flexible printed circuit structures  72  or may be separate from flexible printed circuit structures  72 . Flexible printed circuit  108  may be omitted if desired. 
     If desired, inductor  86  may be formed as a part of interconnect structures  104 . Interconnect structures  104  may include a conductive clip, a conductive pin, a conductive spring, conductive adhesive, solder, welds, conductive foam, a conductive bracket, a conductive screw, a conductive fastener, a conductive screw boss, a conductive (e.g., radio-frequency) connector, conductive traces, strips of metal, sheet metal, a flexible printed circuit (e.g., a flexible printed circuit that is separate from flexible printed circuit  108  or that forms a part of flexible printed circuit  108  in scenarios where flexible printed circuit  108  is used to form a substrate for conductive traces in conductive path  115 ), and/or any other desired structures that couple segment  78  to conductive support plate  58  between antenna feed  50 - 2  and knuckle  118 . 
     In scenarios where interconnect structures  104  include a flexible printed circuit, inductor  86  may include an SMT inductor mounted to the flexible printed circuit. In scenarios where interconnect structures  104  do not include a flexible printed circuit, inductor  86  may be formed from an elongated conductive member that is configured to exhibit a selected inductance, as an example. If desired, an antenna tuning component for non-NFC antenna  40 - 2  may also be mounted to or formed from interconnect structures  104  (e.g., interconnect structures  104  may include inductors, capacitors, switches, resistors, and/or any other components arranged in any desired manner for tuning the frequency response of antenna  40 - 2  in one or more non-NFC frequency bands such as within a cellular low band). 
     If desired, inductor  88  may be formed as a part of interconnect structures  106 . Interconnect structures  106  may include a conductive clip, a conductive pin, a conductive spring, conductive adhesive, solder, welds, conductive foam, a conductive bracket (e.g., a mounting bracket for a camera overlapping conductive support plate  58  that optionally couples conductive structures on the camera sensor to ground), a conductive screw, a conductive fastener, a conductive screw boss, a conductive (e.g., radio-frequency) connector, conductive traces, strips of metal, sheet metal, a flexible printed circuit (e.g., a flexible printed circuit that is separate from flexible printed circuit  108  or that forms a part of flexible printed circuit  108  in scenarios where flexible printed circuit  108  is used to form a substrate for conductive traces in conductive path  115 ), and/or any other desired structures that couple terminal  100  on segment  80  to terminal  98  on conductive support plate  58 . In scenarios where interconnect structures  106  include a flexible printed circuit, inductor  88  may include an SMT inductor mounted to the flexible printed circuit. In scenarios where interconnect structures  106  do not include a flexible printed circuit, inductor  88  may be formed from an elongated conductive member that is configured to exhibit a selected inductance, as an example. If desired, an antenna tuning component for non-NFC antenna  40 - 3  may also be mounted to or formed from interconnect structure  106  (e.g., for tuning the frequency response of non-NFC antenna  40 - 3  in one or more non-NFC frequency bands). 
     As shown in  FIG. 5 , an inductor such as inductor  74  may be interposed on conductive path  68 . Inductor  74  may have a terminal coupled to point  76  on segment  78  and a second terminal coupled to signal terminal  62 . Inductor  74  may be mounted to flexible printed circuit structures  72  or may be separate from flexible printed circuit structures  72 . If desired, antenna tuning components for non-NFC antenna  40 - 2  and/or non-NFC antenna  40 - 1  may also be mounted to flexible printed circuit structures  72  (e.g., for tuning the frequency response of non-NFC antennas  40 - 1  and  40 - 2  in one or more non-NFC frequency bands). 
     Similarly, an inductor such as inductor  90  may be interposed on conductive path  70 . Inductor  90  may have a first terminal coupled to point  102  on segment  80  and a second terminal coupled to signal terminal  66 . Inductor  90  may be mounted to flexible printed circuit structures  72  or may be separate from flexible printed circuit structures  72 . If desired, antenna tuning components for non-NFC antenna  40 - 3  may also be mounted to flexible printed circuit structures  72  (e.g., for tuning the frequency response of non-NFC antenna  40 - 3  in one or more non-NFC frequency bands). Inductors  74 ,  86 ,  88 , and/or  90  may each partially or entirely overlap slot  60  if desired. 
     Conductive path  68  may, for example, include conductive traces on flexible printed circuit structures  72  (e.g., the same flexible printed circuit used as a substrate for inductor  74  or a different flexible printed circuit). Conductive path  70  may, for example, include conductive traces on flexible printed circuit structures  72  (e.g., the same flexible printed circuit used as a substrate for inductor  74  or a different flexible printed circuit, the same flexible printed circuit used as a substrate for conductive path  68  or a different flexible printed circuit, etc.). 
     If desired, a high-pass filter such as capacitor  110  may be coupled between antenna feed  50 - 2  and segment  78 . Capacitor  110  may form a short circuit impedance or a very low impedance (e.g., an impedance less than a threshold impedance) in the non-NFC frequency bands handled by non-NFC antenna  40 - 2 . When non-NFC antenna  40 - 2  is transmitting non-NFC signals, antenna feed  50 - 2  may produce antenna currents (e.g., currents at frequencies in the non-NFC frequency bands handled by non-NFC antenna  40 - 2 ) that flow along segment  78  of peripheral conductive housing structures  12 W. The antenna currents may produce corresponding non-NFC signals that are radiated into free space. When non-NFC antenna  40 - 2  is receiving non-NFC signals, the received non-NFC signals may produce antenna currents on segment  78 . The corresponding non-NFC signals may be provided to non-NFC transceiver circuitry  36  over antenna feed  50 - 2 . Inductor  74  and inductor  86  may have inductances that configure the inductors to form low-pass filters that block antenna currents in the non-NFC frequency bands from passing from segment  78  onto conductive support plate  58  or conductive path  68  (e.g., inductors  74  and  86  may form open circuit impedances or very high impedances such as impedances that are greater than a threshold impedance in the non-NFC frequency bands handled by non-NFC antenna  40 - 2 ). This may, for example, prevent the non-NFC signals handled by non-NFC antenna  40 - 2  from interfering with the operation of NFC transceiver circuitry  38 . 
     If desired, a high-pass filter such as capacitor  112  may be coupled between antenna feed  50 - 3  and segment  80 . Capacitor  112  may form a short circuit impedance or a very low impedance (e.g., an impedance less than a threshold impedance) in the non-NFC frequency bands handled by non-NFC antenna  40 - 3 . When non-NFC antenna  40 - 3  is transmitting non-NFC signals, antenna feed  50 - 3  may produce antenna currents (e.g., currents at frequencies in the non-NFC frequency bands handled by non-NFC antenna  40 - 3 ) that flow along segment  80  of peripheral conductive housing structures  12 W. The antenna currents may produce corresponding non-NFC signals that are radiated into free space. When non-NFC antenna  40 - 3  is receiving non-NFC signals, the received non-NFC signals may produce antenna currents on segment  80 . The corresponding non-NFC signals may be provided to non-NFC transceiver circuitry  36  over antenna feed  50 - 3 . Inductor  88  and inductor  90  may have inductances that configure the inductors to form low-pass filters that block antenna currents in the non-NFC frequency bands from passing from segment  80  onto conductive support plate  58  or conductive path  70  (e.g., inductors  88  and  90  may form open circuit impedances or very high impedances such as impedances that are greater than a threshold impedance in the non-NFC frequency bands handled by non-NFC antenna  40 - 3 ). This may, for example, prevent the non-NFC signals handled by non-NFC antenna  40 - 3  from interfering with the operation of NFC transceiver circuitry  38 . 
     The low-pass filters formed from inductors  74 ,  86 ,  88 , and  90  pass the NFC signals handled by NFC transceiver circuitry  38  (e.g., inductors  74 ,  86 ,  88 , and  90  may form short circuit impedances or very low impedances that are less than a threshold impedance in the NFC frequency band). Capacitors  110  and  112  may block relatively low frequency current such as antenna current I from passing onto antenna feeds  50 - 2  and  50 - 3  and interfering with the operation of non-NFC transceiver circuitry  36 . When NFC antenna  40 NFC is transmitting NFC signals, differential antenna feed  50 D may produce antenna current I at frequencies in the NFC frequency band. Antenna current I may flow along conductive loop path  114 . For example, antenna current I may flow through signal terminal  62 , through conductive path  68 , through inductor  74 , through segment  78  (e.g., through the portion of segment  78  extending between point  76  and terminal  94  of inductor  86 ), through inductor  86 , through conductive path  115 , through inductor  88 , through segment  80  (e.g., between terminal  100  of inductor  88  and point  102 ), through inductor  90 , through conductive path  70 , and through signal terminal  66 . Corresponding NFC signals may be radiated into free space. Similarly, when NFC antenna  40 NFC is receiving NFC signals, the received signals may produce antenna currents I on conductive loop path  114 . The corresponding NFC signals may be provided to NFC transceiver circuitry  38  over differential antenna feed  50 D. 
     The example of  FIG. 5  is merely illustrative. Inductors  75 ,  86 ,  88 , and  90  may each include any desired number of fixed or adjustable inductive components (e.g., discrete or continuous inductors) coupled together in any desired manner. Slot  60 , segment  78 , segment  80 , and conductive loop path  114  may have other shapes (e.g., shapes having any desired number of straight and/or curved portions and any desired number of straight and/or curved edges). 
     When configured using the arrangement of  FIG. 5 , antenna current I may run between segment  78  and conductive support plate  58  at a location that is relatively far from segment  80  and point  102  (e.g., at a location that is near to the central longitudinal axis of device  10 ). In scenarios where flexible printed circuit  108  is omitted (e.g., scenarios where conductive path  115  of conductive loop path  114  runs through conductive support plate  58 ), if care is not taken, this relatively large distance may cause some of the antenna current I along conductive path  115  to leak around the edges of opening  122 , as shown by path  120 . This current leakage between terminals  96  and  98  may undesirably limit the overall field strength and/or effective volume of NFC antenna  40 NFC. In order to mitigate these issues, inductor  86  may be coupled between knuckle  118  and conductive support plate  58 . 
       FIG. 6  is a diagram showing how inductor  86  may be coupled between knuckle  118  and conductive support plate  58 . As shown in  FIG. 6 , terminal  94  of inductor  86  may be coupled to knuckle  118  (e.g., terminal  94  may be coupled to the end of segment  78  and thus the end of the antenna resonating element arm of non-NFC antenna  40 - 2  at gap  18 - 2 ). Interconnect structures  104  may remain coupled between segment  78  (e.g., at terminal  124 ) and conductive support plate  58  (e.g., at terminal  126 ). Interconnect structures  104  may, for example, include an antenna tuning component for tuning the frequency response of non-NFC antenna  40 - 2  in one or more non-NFC frequency bands (e.g., the cellular low band). If desired, interconnect structures  104  may include a high pass filter such as capacitor  128  coupled between terminals  124  and  126 . The high pass filter (e.g., capacitor  128 ) may pass antenna currents in the non-NFC frequency bands handled by non-NFC antenna  40 - 2  while blocking antenna currents I in the NFC frequency band (e.g., capacitor  128  may prevent antenna current I from shorting to terminal  126 ). 
     Terminal  124  may be interposed on segment  78  between knuckle  118  (terminal  94 ) and antenna feed  50 - 2 . Terminal  126  may be interposed on conductive support plate  58  (e.g., at edge  59 ) between antenna feed  50 - 2  and terminal  96  of inductor  86  (e.g., terminal  96  may be located farther away from the central longitudinal axis of device  10  than in the arrangement of  FIG. 5  such that terminal  96  is interposed between terminal  126  and terminal  98  of inductor  88 ). Conductive loop path  114  may include conductive path  115 ′ on conductive support plate  58 , extending between terminals  96  and  98  (e.g., conductive path  115 ′ of  FIG. 6  may be shorter than conductive path  115  of  FIG. 5 ). Coupling inductor  86  to segment  78  at or adjacent to gap  18 - 2  (e.g., at knuckle  118 ) may prevent the formation of leakage current around opening  122  as the current passes between terminals  96  and  98 . This may serve to maximize the overall field strength (e.g., by as much as 1.3 dB or more) and the effective volume of NFC antenna  40 NFC (e.g., by as much as 50% or more). 
     If desired, impedance matching circuitry may be coupled between NFC transceiver circuitry  38  and NFC antenna  40 NFC to help match the impedance of NFC transceiver circuitry  38  with the impedance of NFC antenna  40 NFC.  FIG. 7  is a schematic diagram showing how impedance matching circuitry may be coupled between NFC transceiver circuitry  38  and NFC antenna  40 NFC in one suitable arrangement. 
     As shown in  FIG. 7 , wireless circuitry  34  may include NFC transceiver circuitry  38  mounted to an underlying substrate  130  (e.g., a main logic board for device  10 ). Signal terminals  62  and  66  of NFC transceiver circuitry  38  may be coupled to conductive paths  68  and  70 , respectively, via impedance matching circuitry  132  (e.g., an impedance matching network formed on substrate  130 ). Conductive paths  68  and  70  may pass through flexible printed circuit structures  72  to opposing ends of conductive loop path  114  of NFC antenna  40 NFC. 
     Impedance matching circuitry  132  may include a network of inductive, capacitive, and/or resistive components that help to match the impedance of NFC transceiver circuitry  38  to the impedance of NFC antenna  40 NFC. However, because impedance matching circuitry  132  is relatively far from conductive loop path  114  in this example, a relatively high amount of radio-frequency energy provided to NFC antenna  40 NFC (e.g., by differential signal pair S+/S−) may be reflected back towards NFC transceiver circuitry  38 , as shown by arrows  134 . This may limit the overall antenna efficiency and performance of NFC antenna  40 NFC. 
     In order to further optimize impedance matching for NFC antenna  40 NFC, additional impedance matching circuits may be formed on flexible printed circuit structures  72 .  FIG. 8  is a schematic diagram showing how additional impedance matching circuits may be formed on flexible printed circuit structures  72 . 
     As shown in  FIG. 8 , flexible printed circuit structures  72  may include additional impedance matching circuits such as impedance matching circuit  136  and impedance matching circuit  138 . Impedance matching circuit  136  may be interposed on conductive path  68  (e.g., at NFC antenna  40 NFC and interposed between inductor  74  ( FIGS. 5 and 6 ) and impedance matching circuitry  132 ). Impedance matching circuit  136  may include a network of inductive, capacitive, and/or resistive components that help to match the impedance of conductive path  68  to the impedance of NFC antenna  40 NFC. Similarly, impedance matching circuit  138  may be interposed on conductive path  70  (e.g., at NFC antenna  40 NFC and interposed between inductor  90  ( FIGS. 5 and 6 ) and impedance matching circuitry  132 ). Impedance matching circuit  138  may include a network of inductive, capacitive, and/or resistive components that help to match the impedance of conductive path  70  to the impedance of NFC antenna  40 NFC. 
     Impedance matching circuits  136  and  138  may help improve the impedance match between NFC transceiver circuitry  38  and NFC antenna  40 NFC relative to arrangements in which impedance matching circuits  136  and  138  are omitted. As one example, in the arrangement of  FIG. 7 , impedance matching circuitry  132  may exhibit a capacitance of 3300 pF while conductive paths  68  and  70  and/or other structures on flexible printed circuit structures  72  exhibit a capacitance of 47 pF to create a peak coupling efficiency of −16.9 dB. However, in the arrangement of  FIG. 8 , impedance matching circuits  136  and  138  may exhibit a capacitance of 3300 pF while impedance matching circuitry  132  exhibits a capacitance of 200 pF, as just one example. Redistributing the impedance matching components for NFC antenna  40 NFC in this way may increase peak coupling efficiency to −15.2 dB while also increasing the effective operational volume of NFC antenna  40 NFC by as much as 2 dB or greater. 
     In one suitable arrangement, the impedance matching scheme of  FIG. 7  may be used when NFC antenna  40 NFC includes an inductor  86  in interconnect structures  104  (e.g., as shown in  FIG. 5 ) whereas the impedance matching scheme of  FIG. 8  is used when NFC antenna  40 NFC includes an inductor  86  coupled to knuckle  118  (e.g., as shown in  FIG. 6 ). This is merely illustrative and, in general, the impedance matching schemes of  FIG. 7 or 8  may be used in either of the arrangements of  FIGS. 5 and 6 . Other impedance matching schemes may be used if desired. 
     Additionally or alternatively, one or more antenna tuning components for non-NFC antenna  40 - 2  and/or non-NFC antenna  40 - 3  may also be used to perform impedance matching in the NFC frequency band for NFC antenna  40 NFC.  FIG. 9  is a circuit diagram of one illustrative antenna tuning component for non-NFC antenna  40 - 2  or non-NFC antenna  40 - 3  that may also be used to perform impedance matching for NFC antenna  40 NFC. 
     As shown in  FIG. 9 , antenna tuning component  140  may include a short pin clip  142 , a capacitor  146 , an inductor  150 , and a capacitor  154 . Capacitor  146 , inductor  150 , and capacitor  154  may be formed on flexible printed circuit structures  72  of  FIGS. 5-8 , for example. Short pin clip  142  may be coupled to circuit node  144  and to segment  78  or segment  80  ( FIGS. 5 and 6 ) to form a return path for non-NFC antennas  40 - 2  or  40 - 3 . Capacitor  146  may be coupled between circuit node  144  and terminal  148 . Terminal  148  may, for example, be coupled to conductive traces on the flexible printed circuit structures, the conductive support plate, or elsewhere. Inductor  150  may be coupled between circuit node  144  and NFC input terminal  152 . NFC input terminal  152  may be coupled to conductive path  68  (signal terminal  62 ) or conductive path  70  (signal terminal  66 ) of  FIGS. 5-8 . Capacitor  154  may be coupled between NFC input terminal  152  and ground terminal  156 . 
     Inductor  150  may have an inductance that configures inductor  150  to block radio-frequency signals in the non-NFC frequency bands handled by the non-NFC antenna. The inductance of inductor  150  may also configure inductor  150  to pass radio-frequency signals in the NFC frequency band. Capacitor  146  may have a capacitance that configures capacitor  146  to block radio-frequency signals in the NFC frequency band. The capacitance of capacitor  146  may also configure capacitor  146  to pass radio-frequency signals in the non-NFC frequency bands. This may cause the radio-frequency signals in the non-NFC frequency bands to pass from short pin clip  142  to ground through capacitor  146  and terminal  148 , as shown by arrow  158 . This may also cause the radio-frequency signals in the NFC frequency band to pass from NFC input terminal  152  to the antenna resonating element arm of the non-NFC antenna (e.g., segment  78  or segment  80  of  FIGS. 5 and 6 ) through inductor  150  and short pin clip  142 , as shown by arrow  160 . Capacitor  154  may have a capacitance that is selected to perform impedance matching in the NFC frequency band for the NFC antenna. If desired, inductor  150  and/or capacitor  154  may help to tune the frequency response of the non-NFC antenna coupled to short pin clip  142 . As one example, inductor  150  may have an inductance between 5-10 nH and capacitor  154  may have a capacitance of 40-60 pF. This is example is merely illustrative. Antenna tuning component  140  may have other circuit configurations if desired. 
     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: 20200922
Publication Date: 20220118
Grant Date: 20220118
Priority Date: 20200922
Inventors: WANG, Yiren
Zhang, Daisong
IRCI, Erdinc
WANG, HAN
HU, HONGFEI
ZHONG, JINGNI
HAN, LIANG
PASCOLINI, MATTIA
CHEN, MING
JIN, NANBO
YU, TIEJUN
ZHOU, YIJUN
TAO, YUAN
XU, YUANCHENG
Assignee: APPLE INC
CPC Classifications: [{"code": "H04B1/40", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/40", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/0075", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/02", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B1/40", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/48", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B5/48", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B5/24", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B5/24", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 79293985