PATENT DOCUMENT

Publication Number: US-9559425-B2
Application Number: US-201414221133-A
Country: US
Kind Code: B2

Title: Electronic device with slot antenna and proximity sensor

Abstract:
An electronic device may be provided with slot antennas. A slot antenna may be formed from metal structures that have a dielectric gap defining an antenna slot. The metal structures may include multiple metal layers that overlap a plastic antenna window and that serve as capacitive electrodes in a capacitive proximity sensor. The metal structures may also include a metal electronic device housing. The metal electronic device housing and the metal layers may be formed on opposing sides of the antenna slot. The metal layers may have a notch that locally widens the antenna slot at an open end of the antenna slot. One of the metal layers may be shorted to the metal electronic device housing at an opposing closed end of the antenna slot. The antenna slot may be indirectly fed using a near-field-coupled antenna feed structure such as a metal patch that overlaps the antenna slot.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 radio-frequency transceiver circuitry that generates radio-frequency signals at a given frequency; 
 a slot antenna that transmits the radio-frequency signals at the given frequency; 
 a metal housing; 
 a dielectric antenna window in the metal housing; 
 metal structures on the dielectric antenna window that are separated from the metal housing by a slot antenna resonating element in the slot antenna, wherein the metal structures and the metal housing define a shape of the slot antenna resonating element, and the slot antenna comprises a near-field-coupled antenna feed structure that is formed over and near-field coupled to the slot antenna resonating element. 
 
     
     
       2. The electronic device defined in  claim 1  wherein the slot antenna resonating element comprises an indirectly fed slot antenna resonating element. 
     
     
       3. The electronic device defined in  claim 2  wherein the near-field-coupled antenna feed structure has a planar metal structure that is near-field coupled to the indirectly fed slot antenna resonating element. 
     
     
       4. The electronic device defined in  claim 3  wherein the planar metal structure comprises a patch that overlaps the indirectly fed slot antenna resonating element. 
     
     
       5. The electronic device defined in  claim 4  wherein the metal structures comprise capacitive proximity sensor electrode structures. 
     
     
       6. The electronic device defined in  claim 5  wherein the capacitive proximity sensor electrode structures comprises a first metal layer and a second metal layer. 
     
     
       7. The electronic device defined in  claim 6  wherein the second metal layer is coupled to the metal housing through a capacitor. 
     
     
       8. The electronic device defined in  claim 7  further comprising a first inductor coupled to the first metal layer and a second inductor coupled to the second metal layer. 
     
     
       9. The electronic device defined in  claim 8  further comprising proximity sensor circuitry coupled to the first and second inductors. 
     
     
       10. The electronic device defined in  claim 9  wherein the second metal layer has a protruding portion that is shorted to the metal housing. 
     
     
       11. The electronic device defined in  claim 10  wherein the indirectly fed slot antenna resonating element has a closed end formed by the protruding portion and has an open end. 
     
     
       12. The electronic device defined in  claim 11  wherein the indirectly fed slot antenna resonating element has a locally widened portion at the open end. 
     
     
       13. The electronic device defined in  claim 12  wherein the first and second metal layers have a notch and wherein the locally widened portion is formed by the notch in the first and second metal layers. 
     
     
       14. The electronic device defined in  claim 1  wherein the slot antenna is an indirectly fed slot antenna having a near-field-coupled antenna feed structure that is near-field coupled to the slot antenna resonating element of the indirectly fed slot antenna and the radio-frequency transceiver circuitry is coupled to the near-field-coupled antenna feed structure, the electronic device further comprising:
 capacitive proximity sensor circuitry coupled to the metal structures. 
 
     
     
       15. The electronic device defined in  claim 14  further comprising inductors coupled between the capacitive proximity sensor circuitry and the metal structures. 
     
     
       16. The electronic device defined in  claim 15  wherein the metal structures comprise first and second metal layers, the electronic device further comprising a dielectric layer between the first and second metal layers. 
     
     
       17. An electronic device, comprising:
 a dielectric member; 
 first metal structures overlapping the dielectric member, wherein the first metal structures comprise first and second metal layers; 
 second metal structures separated from the first metal structures by an antenna slot, wherein the second metal structures comprise a metal electronic device housing and the second metal layer has a protruding portion that extends over the antenna slot and is shorted to the metal electronic device housing during operation of the antenna slot; and 
 a near-field-coupled antenna feed structure that is near-field coupled to and formed above the antenna slot, wherein the near-field-coupled antenna feed structure and the antenna slot form a slot antenna. 
 
     
     
       18. The electronic device defined in  claim 17  further comprising capacitive proximity sensor circuitry coupled to the first and second metal layers. 
     
     
       19. Apparatus, comprising:
 a metal electronic device housing; 
 a plastic antenna window in the metal electronic device housing; 
 first and second metal layers overlapping the plastic antenna window, wherein the first and second metal layers are separated from the metal electronic device housing by an antenna slot, the first metal layer is between the second metal layer and the plastic antenna window, the antenna slot has opposing open and closed ends, and the second metal layer is coupled to the metal electronic device housing at the closed end of the antenna slot; and 
 capacitive proximity sensor circuitry coupled to the first and second metal layers. 
 
     
     
       20. The apparatus defined in  claim 19  further comprising:
 a near-field-coupled antenna feed structure that is near-field coupled to the antenna slot, wherein the near-field-coupled antenna feed structure and the antenna slot form a slot antenna. 
 
     
     
       21. The apparatus defined in  claim 20  wherein the near-field-coupled antenna feed structure comprises a metal patch that overlaps the slot. 
     
     
       22. The apparatus defined in  claim 21  wherein the antenna slot has opposing open and closed ends, the apparatus further comprising:
 a radio-frequency transceiver coupled to the near-field-coupled antenna feed structure, wherein the first and second metal layers have a notch that locally widens the slot at the open end of the slot and wherein the second metal layer is coupled to the metal electronic device housing at the closed end of the slot. 
 
     
     
       23. An electronic device, comprising:
 radio-frequency transceiver circuitry that generates radio-frequency signals at a given frequency; 
 a slot antenna that transmits the radio-frequency signals at the given frequency; 
 a metal housing; 
 a plastic antenna window in the housing; and 
 metal structures on a surface of the plastic antenna window that are separated from the metal housing by a slot antenna resonating element in the slot antenna, wherein portions of the metal structures on the plastic antenna window and portions of the metal housing define a shape of the slot antenna resonating element in the slot antenna, the slot antenna resonating element has opposing open and closed ends, and the metal structures are coupled to the metal housing at the closed end of the antenna slot resonating element. 
 
     
     
       24. The electronic device defined in  claim 23  wherein the slot antenna comprises an indirectly fed slot antenna. 
     
     
       25. The electronic device defined in  claim 24  wherein the slot antenna comprises a first indirectly fed slot antenna and wherein the electronic device further comprises a second indirectly fed slot antenna formed from portions of the metal structures on the plastic antenna window and portions of the metal housing. 
     
     
       26. The electronic device defined in  claim 25  wherein the first and second indirectly fed slot antennas have open ends that face each other.

Description:
BACKGROUND 
     This relates generally to electronic devices and, more particularly, to electronic devices with antennas. 
     Electronic devices often include antennas. For example, cellular telephones, computers, and other devices often contain antennas for supporting wireless communications. 
     It can be challenging to form electronic device antenna structures with desired attributes. In some wireless devices, the presence of conductive housing structures can influence antenna performance. Antenna performance may not be satisfactory if the housing structures are not configured properly and interfere with antenna operation. Device size can also affect performance. It can be difficult to achieve desired performance levels in a compact device, particularly when the compact device has conductive housing structures. Challenges also arise when incorporating sensors into electronic devices with conductive housing structures. 
     It would therefore be desirable to be able to provide improved wireless circuitry for electronic devices such as electronic devices that include conductive housing structures. 
     SUMMARY 
     An electronic device may be provided with antennas. The antennas for the electronic device may be formed from slot antenna structures. A slot antenna structure may include portions of a metal housing for an electronic device. A dielectric antenna window may be formed in the metal housing. Metal structures on the dielectric antenna window and portions of the metal housing may be separated by an antenna slot that is used in forming a slot antenna. 
     The antenna slot in a slot antenna may be indirectly fed. Proximity sensor electrodes for a capacitive proximity sensor may be formed by first and second metal layers overlapping the dielectric antenna window. The first metal layer may be located between the second metal layer and the antenna window. A notch may be formed in the first and second metal layers to locally widen the antenna slot at an open end of the antenna slot. The second metal layer may be shorted to the metal electronic device housing at an opposing closed end of the antenna slot. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative electronic device such as a laptop computer in accordance with an embodiment. 
         FIG. 2  is a perspective view of an illustrative electronic device such as a handheld electronic device in accordance with an embodiment. 
         FIG. 3  is a perspective view of an illustrative electronic device such as a tablet computer in accordance with an embodiment. 
         FIG. 4  is a perspective view of an illustrative electronic device such as a display for a computer or television in accordance with an embodiment. 
         FIG. 5  is a schematic diagram of illustrative circuitry in an electronic device in accordance with an embodiment. 
         FIG. 6  is a schematic diagram of illustrative wireless circuitry in accordance with an embodiment. 
         FIG. 7  is a schematic diagram of illustrative wireless circuitry in which multiple antennas have been coupled to transceiver circuitry using switching circuitry in accordance with an embodiment. 
         FIG. 8  is a diagram of an illustrative inverted-F antenna in accordance with an embodiment. 
         FIG. 9  is a diagram of an illustrative antenna that is fed using near-field coupling in accordance with an embodiment. 
         FIG. 10  is a perspective view of a slot antenna being fed using near-field coupling in accordance with an embodiment. 
         FIG. 11  is a perspective view of an interior portion of an electronic device housing having a pair of slots and associated near-field coupling structures in accordance with an embodiment. 
         FIG. 12  is a perspective view of an illustrative interior portion of an electronic device having electronic device housing slots with multiple widths that are fed using near-field coupling structures and having a hybrid antenna that includes a planar inverted-F antenna structure and a slot antenna structure in accordance with an embodiment. 
         FIG. 13  is a perspective view of an illustrative interior portion of an electronic device having slot antennas formed from metal traces on a plastic antenna window in a metal housing for the electronic device in accordance with an embodiment. 
         FIG. 14  is a diagram showing how electrical components may be incorporated into a slot antenna to adjust antenna performance in accordance with an embodiment. 
         FIG. 15  is a diagram of illustrative wireless circuitry that includes capacitive proximity sensor electrode structures formed from metal antenna structures in accordance with an embodiment. 
         FIG. 16  is a perspective view of illustrative structures of the type that may be used in forming an indirectly fed slot antenna and capacitive proximity sensor electrodes in accordance with an embodiment. 
         FIG. 17  is a cross-sectional side view of a portion of an electronic device having structures that form an indirectly fed slot antenna and a capacitive proximity sensor in accordance with an embodiment. 
         FIG. 18  is a cross-sectional side view of an edge portion of an illustrative electronic device having a slot antenna and capacitive proximity sensor electrode structures in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices may be provided with antennas. The antennas may include slot antennas formed in device structures such as electronic device housing structures. Illustrative electronic devices that have housings that accommodate slot antennas are shown in  FIGS. 1, 2, 3 , and  4 . 
     Electronic device  10  of  FIG. 1  has the shape of a laptop computer and has upper housing  12 A and lower housing  12 B with components such as keyboard  16  and touchpad  18 . Device  10  has hinge structures  20  (sometimes referred to as a clutch barrel) to allow upper housing  12 A to rotate in directions  22  about rotational axis  24  relative to lower housing  12 B. Display  14  is mounted in housing  12 A. Upper housing  12 A, which may sometimes be referred to as a display housing or lid, is placed in a closed position by rotating upper housing  12 A towards lower housing  12 B about rotational axis  24 . 
       FIG. 2  shows an illustrative configuration for electronic device  10  based on a handheld device such as a cellular telephone, music player, gaming device, navigation unit, or other compact device. In this type of configuration for device  10 , device  10  has opposing front and rear surfaces. The rear surface of device  10  may be formed from a planar portion of housing  12 . Display  14  forms the front surface of device  10 . Display  14  may have an outermost layer that includes openings for components such as button  26  and speaker port  27 . 
     In the example of  FIG. 3 , electronic device  10  is a tablet computer. In electronic device  10  of  FIG. 3 , device  10  has opposing planar front and rear surfaces. The rear surface of device  10  is formed from a planar rear wall portion of housing  12 . Curved or planar sidewalls may run around the periphery of the planar rear wall and may extend vertically upwards. Display  14  is mounted on the front surface of device  10  in housing  12 . As shown in  FIG. 3 , display  14  has an outermost layer with an opening to accommodate button  26 . 
       FIG. 4  shows an illustrative configuration for electronic device  10  in which device  10  is a computer display, a computer that has an integrated computer display, or a television. Display  14  is mounted on a front face of device  10  in housing  12 . With this type of arrangement, housing  12  for device  10  may be mounted on a wall or may have an optional structure such as support stand  30  to support device  10  on a flat surface such as a tabletop or desk. 
     An electronic device such as electronic device  10  of  FIGS. 1, 2, 3, and 4 , may, in general, be a computing device such as a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wrist-watch device, a pendant device, a headphone or earpiece device, or other wearable or miniature device, a television, a computer display that does not contain an embedded computer, a gaming device, a navigation device, an embedded system such as a system in which electronic equipment with a display is mounted in a kiosk or automobile, equipment that implements the functionality of two or more of these devices, or other electronic equipment. The examples of  FIGS. 1, 2, 3, and 4  are merely illustrative. 
     Device  10  may include a display such as display  14 . Display  14  may be mounted in housing  12 . Housing  12 , which may sometimes be referred to as an enclosure or case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of any two or more of these materials. Housing  12  may be formed using a unibody configuration in which some or all of housing  12  is machined or molded as a single structure or may be formed using multiple structures (e.g., an internal frame structure, one or more structures that form exterior housing surfaces, etc.). 
     Display  14  may be a touch screen display that incorporates a layer of conductive capacitive touch sensor electrodes or other touch sensor components (e.g., resistive touch sensor components, acoustic touch sensor components, force-based touch sensor components, light-based touch sensor components, etc.) or may be a display that is not touch-sensitive. Capacitive touch screen electrodes may be formed from an array of indium tin oxide pads or other transparent conductive structures. 
     Display  14  may include an array of display pixels formed from liquid crystal display (LCD) components, an array of electrophoretic display pixels, an array of plasma display pixels, an array of organic light-emitting diode display pixels, an array of electrowetting display pixels, or display pixels based on other display technologies. 
     Display  14  may be protected using a display cover layer such as a layer of transparent glass or clear plastic. Openings may be formed in the display cover layer. For example, an opening may be formed in the display cover layer to accommodate a button, an opening may be formed in the display cover layer to accommodate a speaker port, etc. 
     Housing  12  may be formed from conductive materials and/or insulating materials. In configurations in which housing  12  is formed from plastic or other dielectric materials, antenna signals can pass through housing  12 . Antennas in this type of configuration can be mounted behind a portion of housing  12 . In configurations in which housing  12  is formed from a conductive material (e.g., metal), it may be desirable to provide one or more radio-transparent antenna windows in openings in the housing. As an example, a metal housing may have openings that are filled with plastic antenna windows. Antennas may be mounted behind the antenna windows and may transmit and/or receive antenna signals through the antenna windows. 
     A schematic diagram showing illustrative components that may be used in device  10  is shown in  FIG. 5 . As shown in  FIG. 5 , device  10  may include control circuitry such as storage and processing circuitry  28 . Storage and processing circuitry  28  may include storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid state drive), volatile memory (e.g., static or dynamic random-access-memory), etc. Processing circuitry in storage and processing circuitry  28  may be used to control the operation of device  10 . This processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, application specific integrated circuits, etc. 
     Storage and processing circuitry  28  may be used to run software on device  10 , such as internet browsing applications, voice-over-internet-protocol (VOIP) telephone call applications, email applications, media playback applications, operating system functions, etc. To support interactions with external equipment, storage and processing circuitry  28  may be used in implementing communications protocols. Communications protocols that may be implemented using storage and processing circuitry  28  include internet protocols, wireless local area network protocols (e.g., IEEE 802.11 protocols—sometimes referred to as WiFi®), protocols for other short-range wireless communications links such as the Bluetooth® protocol, cellular telephone protocols, MIMO protocols, antenna diversity protocols, etc. 
     Input-output circuitry  44  may include input-output devices  32 . Input-output devices  32  may be used to allow data to be supplied to device  10  and to allow data to be provided from device  10  to external devices. Input-output devices  32  may include user interface devices, data port devices, and other input-output components. For example, input-output devices may include touch screens, displays without touch sensor capabilities, buttons, joysticks, click wheels, scrolling wheels, touch pads, key pads, keyboards, microphones, cameras, buttons, speakers, status indicators, light sources, audio jacks and other audio port components, digital data port devices, light sensors, motion sensors (accelerometers), capacitance sensors, proximity sensors, etc. 
     Input-output circuitry  44  may include wireless communications circuitry  34  for communicating wirelessly with external equipment. Wireless communications circuitry  34  may include radio-frequency (RF) transceiver circuitry formed from one or more integrated circuits, power amplifier circuitry, low-noise input amplifiers, passive RF components, one or more antennas, transmission lines, and other circuitry for handling RF wireless signals. Wireless signals can also be sent using light (e.g., using infrared communications). 
     Wireless communications circuitry  34  may include radio-frequency transceiver circuitry  90  for handling various radio-frequency communications bands. For example, circuitry  34  may include transceiver circuitry  36 ,  38 , and  42 . Transceiver circuitry  36  may be wireless local area network transceiver circuitry that may handle 2.4 GHz and 5 GHz bands for WiFi® (IEEE 802.11) communications and that may handle the 2.4 GHz Bluetooth® communications band. Circuitry  34  may use cellular telephone transceiver circuitry  38  for handling wireless communications in frequency ranges such as a low communications band from 700 to 960 MHz, a midband from 1710 to 2170 MHz, and a high band from 2300 to 2700 MHz or other communications bands between 700 MHz and 2700 MHz or other suitable frequencies (as examples). Circuitry  38  may handle voice data and non-voice data. Wireless communications circuitry  34  can include circuitry for other short-range and long-range wireless links if desired. For example, wireless communications circuitry  34  may include 60 GHz transceiver circuitry, circuitry for receiving television and radio signals, paging system transceivers, near field communications (NFC) circuitry, etc. Wireless communications circuitry  34  may include satellite navigation system circuitry such as global positioning system (GPS) receiver circuitry  42  for receiving GPS signals at 1575 MHz or for handling other satellite positioning data. In WiFi® and Bluetooth® links and other short-range wireless links, wireless signals are typically used to convey data over tens or hundreds of feet. In cellular telephone links and other long-range links, wireless signals are typically used to convey data over thousands of feet or miles. 
     Wireless communications circuitry  34  may include antennas  40 . Antennas  40  may be formed using any suitable antenna types. For example, antennas  40  may include antennas with resonating elements that are formed from loop antenna structures, patch antenna structures, inverted-F antenna structures, slot antenna structures, planar inverted-F antenna structures, helical antenna structures, hybrids of these designs, etc. Different types of antennas may be used for different bands and combinations of bands. For example, one type of antenna may be used in forming a local wireless link antenna and another type of antenna may be used in forming a remote wireless link antenna. 
     As shown in  FIG. 6 , transceiver circuitry  90  in wireless circuitry  34  may be coupled to antenna structures  40  using paths such as path  92 . Wireless circuitry  34  may be coupled to control circuitry  28 . Control circuitry  28  may be coupled to input-output devices  32 . Input-output devices  32  may supply output from device  10  and may receive input from sources that are external to device  10 . 
     To provide antenna structures  40  with the ability to cover communications frequencies of interest, antenna structures  40  may be provided with circuitry such as filter circuitry (e.g., one or more passive filters and/or one or more tunable filter circuits). Discrete components such as capacitors, inductors, and resistors may be incorporated into the filter circuitry. Capacitive structures, inductive structures, and resistive structures may also be formed from patterned metal structures (e.g., part of an antenna). If desired, antenna structures  40  may be provided with adjustable circuits such as tunable components  102  to tune antennas over communications bands of interest. Tunable components  102  may include tunable inductors, tunable capacitors, or other tunable components. Tunable components such as these may be based on switches and networks of fixed components, distributed metal structures that produce associated distributed capacitances and inductances, variable solid state devices for producing variable capacitance and inductance values, tunable filters, or other suitable tunable structures. 
     During operation of device  10 , control circuitry  28  may issue control signals on one or more paths such as path  104  that adjust inductance values, capacitance values, or other parameters associated with tunable components  102 , thereby tuning antenna structures  40  to cover desired communications bands. 
     Path  92  may include one or more transmission lines. As an example, signal path  92  of  FIG. 6  may be a transmission line having a positive signal conductor such as line  94  and a ground signal conductor such as line  96 . Lines  94  and  96  may form parts of a coaxial cable or a microstrip transmission line (as examples). A matching network formed from components such as inductors, resistors, and capacitors may be used in matching the impedance of antenna structures  40  to the impedance of transmission line  92 . Matching network components may be provided as discrete components (e.g., surface mount technology components) or may be formed from housing structures, printed circuit board structures, traces on plastic supports, etc. Components such as these may also be used in forming filter circuitry in antenna structures  40 . 
     Transmission line  92  may be directly coupled to an antenna resonating element and ground for antenna  40  or may be coupled to near-field-coupled antenna feed structures that are used in indirectly feeding a resonating element for antenna  40 . As an example, antenna structures  40  may form an inverted-F antenna, a slot antenna, a hybrid inverted-F slot antenna or other antenna having an antenna feed with a positive antenna feed terminal such as terminal  98  and a ground antenna feed terminal such as ground antenna feed terminal  100 . Positive transmission line conductor  94  may be coupled to positive antenna feed terminal  98  and ground transmission line conductor  96  may be coupled to ground antenna feed terminal  100 . As another example, antenna structures  40  may include an antenna resonating element such as a slot antenna resonating element or other element that is indirectly fed using near-field coupling. In a nearfield coupling arrangement, transmission line  92  is coupled to a near-field-coupled antenna feed structure that is used to indirectly feed antenna structures such as an antenna slot or other element through near-field electromagnetic coupling. 
     As shown in  FIG. 7 , antenna structures  40  may include multiple antennas such as secondary antenna  40 A and primary antenna  40 B. Primary antenna  40 B may be used for transmitting and receiving wireless signals. Secondary antenna  40 A may be switched into use when antenna  40 B is blocked or otherwise degraded in performance (e.g., to receive and, if desired, to transmit wireless signals). Switching circuitry  200  may be used to select which of antennas  40 A and  40 B is coupled to transceiver circuitry  90 . If desired, primary antenna  40 B and/or secondary antenna  40 A may cover multiple frequency bands of interest (e.g., a low band cellular band, a midband cellular band including GPS coverage, and a high band cellular band that may cover 2.4 GHz communications, if desired). Other communications band may be covered using antennas  40 A and  40 B, if desired. 
       FIG. 8  is a diagram of illustrative inverted-F antenna structures that may be used in forming an antenna in device  10 . Inverted-F antenna  40  of  FIG. 8  has antenna resonating element  106  and antenna ground (ground plane)  104 . Antenna resonating element  106  may have a main resonating element arm such as arm  108 . The length of arm  108  may be selected so that antenna  40  resonates at desired operating frequencies. For example, if the length of arm  108  may be a quarter of a wavelength at a desired operating frequency for antenna  40 . Antenna  40  may also exhibit resonances at harmonic frequencies. 
     Main resonating element arm  108  may be coupled to ground  104  by return path  110 . Antenna feed  112  may include positive antenna feed terminal  98  and ground antenna feed terminal  100  and may run in parallel to return path  110  between arm  108  and ground  104 . If desired, inverted-F antennas such as illustrative antenna  40  of  FIG. 4  may have more than one resonating arm branch (e.g., to create multiple frequency resonances to support operations in multiple communications bands) or may have other antenna structures (e.g., parasitic antenna resonating elements, tunable components to support antenna tuning, etc.). A planar inverted-F antenna (PIFA) may be formed by implementing arm  108  using planar structures (e.g., a planar metal structure such as a metal patch or strip of metal that extends into the page of  FIG. 8 ). 
       FIG. 9  shows how antenna  40  may be indirectly fed using a near-field coupling arrangement. With this type of arrangement, transceiver  90  is connected to near-field-coupled antenna feed structure  202  by transmission line  92 . Antenna  40  may include a resonating element such as a slot or other antenna resonating element structure (antenna element  40 ′). Structure  202  may include a strip of metal, a patch of metal, planar metal members with other shapes, a loop of metal, or other structure that is near-field coupled to antenna resonating element  40 ′ by near-field coupled electromagnetic signals  204 . Structure  202  does not produce significant far-field radiation during operation (i.e., structure  202  does not itself form a far-field antenna but rather serves as a coupled feed for a slot antenna structure or other antenna resonating element structure for antenna  40 ). During operation, the indirect feeding of element  40 ′ by structure  202  allows antenna element  40 ′ and therefore antenna  40  to receive and/or transmit far-field wireless signals  205  (i.e., radio-frequency antenna signals for antenna  40 ). 
     A perspective view of an illustrative indirectly feed (coupled feed) configuration in which a slot-based antenna is being indirectly fed is shown in  FIG. 10 . With the arrangement of  FIG. 10 , antenna  40  is a slot-based antenna formed from antenna slot  206  in a ground plane structure such as metal housing  12  of device  10 . Slot  206  may be filled with plastic or other dielectric. In the example of  FIG. 10 , slot  206  has an open end such as end  218  and an opposing closed end such as closed end  208 . A slot antenna such as slot antenna  40  of  FIG. 10  that has an open end and a closed end may sometimes be referred to as an open slot antenna. If desired, slot antenna  40  may be a closed slot antenna (i.e., end  218  may be closed by providing a short circuit path across the slot opening at end  218  so that both ends of the slot are closed). Slot antenna  40  of  FIG. 10  is based on a slot that has bend  210 . If desired, slots for slot antennas such as slot  206  may be provided with two bends, three or more bends, etc. The example of  FIG. 10  is merely illustrative. 
     Slot antenna  40  may be near-field coupled to near-field-coupled antenna feed structure  202 . Structure  202  may be formed from a patch of metal such as patch  212  with a bent leg such as leg  214 . Leg  214  extends downwards towards ground plane  12 . Tip  216  of leg  214  is separated from ground plane  12  by air gap D (i.e., tip  216  is not directly connected to ground  12 ). 
     Transceiver circuitry  90  is coupled to antenna feed terminals such as terminals  98  and  100  by transmission line  92 . Terminal  98  may be connected to tip portion  216  of leg  214  of near-field-coupled antenna feed structure  202 . Terminal  100  may be connected to ground structure  12 . Positive signal line  94  may be coupled to terminal  98 . Ground signal line  96  may be coupled to terminal  100 . 
     Near-field-coupled antenna feed structure  202  is near-field coupled to slot antenna  40  by near-field electromagnetic signals and forms an indirect antenna feed for antenna  40 . During operation, transceiver circuitry  90  can transmit and receive wireless radio-frequency antenna signals with antenna  40  (i.e., with slot  206 ) using coupled feed structure  202 . 
       FIG. 11  is a perspective interior view of an illustrative configuration that may be used for housing  12 . Housing  12  of  FIG. 11  has a rear wall such as planar rear wall  12 - 1  and has flat or curved sidewalls  12 - 2  that run around the periphery of rear wall  12 - 1  and that extend vertically upwards to support display  14  (not shown in  FIG. 11 ). 
     Slots  206 A and  206 B are formed in housing walls  12 - 1  and  12 - 2 . Plastic or other dielectric may be used to fill slots  206 A and  206 B. Slots  206 A and  206 B may be open ended slots having closed ends  208  and open ends  218  or one or both of slots  206 A and  206 B may be closed slots. Slots  206 A and  206 B may have bends such as bends  210 - 1  and  210 - 2  that allow slots  206 A and  206 B to extend across portions of rear wall  12 - 1  and up side walls  12 - 2 . Openings  218  may be formed along upper edge  220  of housing sidewall  12 . Near-field-coupled antenna feed structure  202 A is electromagnetically coupled to slot  206 A and allows slot antenna  40 A to be indirectly feed by transceiver circuitry  90  using terminals  98 A and  100 A. Near-field-coupled antenna feed structure  202 B is electromagnetically coupled to slot  206 B and allows slot antenna  40 B to be indirectly feed by transceiver circuitry  90  using terminals  98 B and  100 B. Switching circuitry such as switching circuitry  200  of  FIG. 7  may be used to couple transceiver circuitry  90  to antennas  40 A and  40 B. Antenna  40 A may be a secondary antenna and antenna  40 B may be a primary antenna (or vice versa). Additional indirectly fed slot antennas  40  may be incorporated into housing  12 , if desired. The two-antenna configuration of  FIG. 11  is merely illustrative. 
       FIG. 12  is a perspective interior view of another illustrative configuration that may be used for providing slot antennas in housing  12 . Housing  12  of  FIG. 12  has a rear wall such as planar rear wall  12 - 1  and has flat or curved sidewalls  12 - 2  that extend upwards from the rear wall around the periphery of device  10 . Slots  206 A,  206 B, and  206 C may be formed in housing walls  12 - 1  and  12 - 2 . Plastic or other dielectric may be used to fill slots  206 A,  206 B, and  206 C. Slots  206 A,  206 B, and  206 C may be open ended slots having closed ends  208  and open ends  218  or one or more of slots  206 A,  206 B, and  206 C may be closed slots that are surrounded on all sides by metal (e.g., metal housing  12 ). 
     Slots  206 A,  206 B, and  206 C may have bends that allow slots  206 A,  206 B, and  206 C to extend across portions of rear wall  12 - 1  and up a given one of sidewalls  12 - 2 . Openings  218  may be formed along upper edge  220  of housing wall  12 . Slots  206 A and  206 B may have locally widened portions such as portions  222  (i.e., portions along the lengths of slots  206 A and  206 B where the widths of the slots have been widened relative to the widths of the slots elsewhere along their lengths). The locally widened slot portion of each slot may exhibit a reduced capacitance that improves low band antenna efficiency. 
     Antennas  40 A and  40 B may be indirectly fed slot antennas. Near-field-coupled antenna feed structure  202 A may be electromagnetically coupled to slot  206 A and may allow slot antenna  40 A to be indirectly feed by transceiver circuitry  90  using terminals  98 A and  100 A. Near-field-coupled antenna feed structure  202 B may be electromagnetically coupled to slot  206 B and may allow slot antenna  40 B to be indirectly feed by transceiver circuitry  90  using terminals  98 B and  100 B. Switching circuitry such as switching circuitry  200  of  FIG. 7  may be used to couple transceiver circuitry  90  to antennas  40 A and  40 B. Antenna  40 A may be a secondary antenna and antenna  40 B may be a primary antenna (or vice versa). 
     Antenna  40 C may be a hybrid antenna that incorporates a slot antenna and a planar inverted-F antenna. The slot antenna portion of antenna  40 C may be formed from slot  206 C. The planar inverted-F portion of antenna  40 C may be formed from a planar inverted-F antenna having main planar resonating element portion  108  (e.g., a rectangular metal patch or a planar metal structure with another suitable shape), a downward-extending leg forming feed path  112 , and another downward-extending leg forming return path  110 . Antenna  40 C may be fed using positive antenna feed terminal  98 C (i.e., a feed terminal on the tip of leg  112  that is separated from ground  12 - 1  by an air gap or other dielectric gap) and ground antenna feed terminal  100 C (e.g., a terminal directly shorted to ground  12  on an opposing side of slot  206 C from terminal  98 C or shorted to ground  12  elsewhere on rear wall  12 - 1 ). 
     Antenna  40 C may operate in one or more communications bands of interest. Both the slot antenna portion of antenna  40 C formed from slot  206 C and the planar inverted-F antenna portion of antenna  40 C may contribute to the antenna performance of antenna  40 C (i.e., both the slot antenna and planar inverted-F antenna may contribute to the antenna resonances of antenna  40 C). This allows the hybrid antenna to effectively cover communications frequencies of interest. With one suitable arrangement, antenna  40 C may operate in 2.4 GHz and 5 GHz communications bands (e.g., to support wireless local area network communications). 
     If desired, antennas for device  10  may be formed from antenna slots that are formed using both metal portions of housing  12  and metal structures on a plastic antenna window structure. This type of arrangement is shown in  FIG. 13 . The arrangement of  FIG. 13  includes antennas  40 A and  40 B. If desired, a third antenna (see, e.g., antenna  40 C of  FIG. 12 ) may be incorporated into device  10  of  FIG. 13 . The configuration of  FIG. 13  is merely illustrative. 
     As shown in  FIG. 13 , metal housing  12  may include metal rear wall  12 - 1  and metal sidewalls  12 - 2  (e.g., curved and/or planar sidewalls). Antenna window  230  may be formed from a plastic structure or other dielectric member mounted in an opening in device housing  12  at one of the ends of device  12  or elsewhere in housing  12 . Metal structures may be formed on the interior surface of antenna window  230  such as metal structure  232 A and metal structure  232 B. Metal structures  232 A and  232 B may be formed from patterned sheet metal (e.g., sheet metal attached to the inner surface of antenna window  230  by adhesive, heat stakes, or other fastening arrangements), metal in a flexible printed circuit (e.g., a flexible printed circuit that is attached to the inner surface of antenna window  230  by adhesive, heat stakes, or other fastening arrangements), metal traces that are globally deposited (e.g., using physical vapor deposition) and subsequently patterned (e.g., using photolithography), patterned metal traces that are deposited using screen printing, pad printing, ink-jet printing, laser-based processing, or other deposition techniques, or other patterned metal structures. 
     The shape of metal structures  232 A and  232 B and the shape of housing  12  are used to define the shapes of slots  206 A and  206 B. Metal structures  232 A and  232 B of  FIG. 13  run along one side of each slot, whereas portions of housing  12  run along the opposing side of each slot. In the illustrative configuration of  FIG. 13 , slots  206 A and  206 B have open ends  218  that face one another in the middle of antenna window  230 . Region  236  between antennas  40 A and  40 B may be used for components (e.g., a camera, a microphone, other input-output devices  32 , etc.). Portion  234 A of metal structure  232 A forms a closed end  208  for slot  206 A. Portion  234 B of metal structure  232 B forms a closed end  208  for slot  206 B. Slot  206 A may be indirectly fed using structure  202 A to form indirectly fed slot antenna  40 A. Slot  206 B may be indirectly fed using structure  202 B to form indirectly fed slot antenna  40 B. 
     If desired, slot antennas in housing  12  may be provided with electrical components such as inductors, capacitors, resistors, and more complex circuitry formed from multiple circuit elements such as these. The components may be packed in surface mount technology (SMT) packages or other packages. 
     The presence of additional electrical components in an antenna may be used to adjust antenna performance, so the antenna covers desired operating frequencies of interest. Consider, as an example, indirectly fed slot antenna  40  of  FIG. 14 . As shown in  FIG. 14 , antenna  40  may have a near-field-coupled antenna feed structure  202  that is used to provide an indirect feed arrangement for slot antenna  40 . Transceiver circuitry  90  may be coupled to feed terminals  98  and  100 , as described in connection with  FIG. 10 . Capacitor C and/or inductor L may be incorporated into antenna  40  using surface mount technology components or other electrical components. One or more capacitors such as capacitor C may, for example, bridge slot  206  at one or more locations along the length of slot  206 . Capacitor C may be implemented using a discrete capacitor or other capacitor structures. Inductor L may be used to form closed end  208  of slot  206  and may be formed from a discrete inductor and/or a length of metal with an associated inductance. The inclusion of capacitor C into antenna  40  may help reduce the size of antenna  40  (e.g., the length of slot  206 ) while ensuring that antenna  40  can continue to operate in desired communications bands. The inclusion of inductor L into antenna  40  may somewhat reduce low band antenna efficiency, but will also help reduce the size of antenna  40  (e.g., by minimizing slot length). Elements such as inductor L and capacitor C may, if desired, be tunable elements so that antenna  40  can be tuned to cover frequencies of interest, as described in connection with tunable components  102  of  FIG. 6 . The use of coupled (indirect) feeding arrangements for the slot antennas in device  10  may help increase antenna bandwidth while minimizing slot length requirements (e.g., by shifting maximum antenna currents towards the edge of housing  12  or via other mechanisms). Other types of feeding arrangements may be used, if desired. 
     It may be desirable to incorporate sensor circuitry into device  10 . For example, proximity sensor circuitry can be used to sense whether a user&#39;s body or other external object is in the vicinity of device  10 . A proximity sensor may be implemented using a capacitive proximity sensor configuration in which capacitance measurements are made using capacitor electrodes. The capacitance measurements may reveal whether or not an external object is within a given distance of the capacitive proximity sensor so that device  10  can take appropriate action. As an example, capacitive proximity sensor data can be used in controlling radio-frequency transmit powers to ensure that wireless circuitry in device  10  satisfies design constraints. 
     To minimize space within device  10 , one or more of the antennas in device  10  may be implemented using conductive structures that serve as both antenna resonating element structures and capacitive proximity sensor electrodes. For example, some or all of a slot antenna ground plane can serve as capacitive proximity sensor electrodes. 
     As shown in  FIG. 15 , conductive structures for forming an antenna in device  10  and for forming proximity sensor electrodes (i.e., antenna resonating element and proximity sensor capacitor electrode structures  312 ) may be coupled to a radio-frequency transceiver such as radio-frequency transceiver  300  in transceiver circuitry  90  to transmit and receive antenna signals. The conductive structures may also be coupled to proximity sensor processing circuitry in storage and processing circuitry  28  to make proximity sensor measurements. Proximity sensor signals (e.g., capacitance measurements) from the capacitor electrodes in structures  312  are gathered using the same conductive components that are serving as all or part of a slot antenna or other antenna structure, so these proximity sensor signals are representative of the distance between external objects such as external object  314  and the antenna. 
     Proximity measurements made using structures  312  may be used in controlling the power of the antenna signals that are transmitted by device  10  through structures  312 . Proximity sensor signals (capacitance measurements) may be conveyed to storage and processing circuitry  28  from structures  312  using path  310 . The proximity sensor signals (capacitance measurements) from structures  312  may be processed using a capacitance-to-digital converter and/or other sensor signal processing circuits in circuitry  28  to produce analog and/or digital proximity data. The proximity data may, for example, be Boolean data indicating that external object  314  (e.g., a user&#39;s body or other external object) is or is not within a given predetermined distance of structures  312  or may be continuous data representing a current distance value for separation distance DST between the antenna and external object  312 . 
     Storage and processing circuitry  28  may be coupled to transceiver circuitry  300  and power amplifier circuitry  302 . Dashed line  308  shows how received radio-frequency signals can be conveyed from the antenna that is formed using structures  312  to transceiver circuitry  300 . During data transmission operations, paths  304  may be used to convey control signals from storage and processing circuitry  28  to transceiver circuitry  300  and power amplifier circuitry  302  to adjust output powers in real time. For example, when data is being transmitted, transceiver  300  and/or power amplifier  302  can be directed to increase or decrease the power level of the radio-frequency signal that is being provided to the antenna over transmission line  306 . Power level adjustments may be made in response to transmit power commands from a wireless network, may be made to cap transmit powers to ensure that regulatory limits for electromagnetic radiation emission are satisfied, and/or may be made to ensure that other desired operating conditions are satisfied. 
     As an example, transmit power can be set to a relatively high level in response to situations in which the proximity sensor has not detected the presence of external object  314 . If, however, proximity sensor measurements indicate that the user&#39;s leg or other body part or other external object  314  is in the immediate vicinity of the antenna and proximity sensor formed from structures  312  (e.g., within 20 mm or less, within 15 mm or less, within 10 mm or less, etc.), storage and processing circuitry  28  can respond accordingly by directing transceiver circuitry  300  and/or power amplifier  302  to transmit radio-frequency signals through transmission line  306  and the antenna of structures  312  at reduced powers. 
     With one embodiment, structures  312  may be formed from metal structures in a slot antenna such as metal structures on one or both sides of slot  206 . As shown in  FIG. 16 , for example, slot antenna  40  may be formed from antenna slot  206  between metal housing  12  and metal structures  232  on the interior surface of dielectric antenna window  230 . Metal structures  232  may include a first layer of metal such as lower layer L 1 . Metal structures  232  may also include a second layer of metal such as upper layer L 2 . Layer L 1  may be interposed between layer L 2  and antenna window  230  (e.g., a plastic antenna window). 
     Layers L 1  and L 2  may have identical or similar shapes, as shown in  FIG. 16 . At high frequencies, layers L 1  and L 2  are effectively shorted together due to the capacitance between layers L 1  and L 2 . This allows layers L 1  and L 2  to form unitary antenna structures in slot antenna  40  (i.e., layers L 1  and L 2  are shorted together to form one half of the ground plane for slot antenna  40  while the portions of metal housing  12  on the opposing side of slot  206  form the other half of the ground plane for slot antenna  40 ). Capacitive proximity sensor measurements are generally made using alternating current (AC) signals at frequencies below the frequencies associated with the antenna signals in device  10 . Antenna signals may have frequencies above 700 MHz (as an example). The frequencies associated with operating a capacitive proximity sensor may be, for example, frequencies of 100 MHz or less, 10 MHz or less, or 1 MHz or less. At these lower frequencies, layers L 1  and L 2  are not shorted together and can serve as proximity sensor electrodes. 
     Layer L 2  may have a protruding portion such as tab  234  that extends across the dielectric of window  230  and forms end  208  of slot  206 . Tab  234  may be grounded to housing  12  and serves as a signal pathway for layer L 2  at end  208 . A capacitor of about 50 pF or other suitable value may be interposed in this path. The capacitor may be shorted at antenna frequencies so that L 1  and L 2  may serve as part of the ground plane for antenna  40 . The capacitor may be open at proximity sensor frequencies to ensure proper operation of the proximity sensor formed from layers L 1  and L 2 . 
     Tab  234  may be shorted to housing  12  by attaching tab  234  to housing  12  using solder, welds, fasteners, conductive adhesive, or other suitable attachment mechanisms. As shown in the example of  FIG. 16 , tab  234  may have an opening such as opening  332  that accommodates screw  234 . Housing  12  may have a threaded opening that receives screw  234 . Screw  234  may be formed from a conductive material such as metal. Using screw  234  and/or metal traces on a structure such as tab  234 , layer L 2  may be coupled to housing  12 . The ability to couple layer L 2  to housing  12  in this way helps to reduce noise in the proximity sensor. Layer L 2  serves as an internal shield layer whereas layer L 1 , which faces outwardly from device  10  through antenna window  230 , serves to gather capacitance measurements that reflect whether external object  314  is in the vicinity of device  10  and antenna  40 . 
     Slot antenna  40  may be near-field coupled to near-field-coupled antenna feed structure  202 . Structure  202  may be formed from metal patch  212 . Metal patch  212  may overlap slot  206 . Bent leg  214  of metal patch  212  may extend downwards towards ground plane  12 . Tip  216  of leg  214  is separated from ground plane  12  by air gap D. Transceiver circuitry  90  is coupled to antenna feed terminals such as terminals  98  and  100  by transmission line  92 . Terminal  98  may be connected to tip portion  216  of leg  214  of near-field-coupled antenna feed structure  202 . Terminal  100  may be connected to metal housing  12 , which forms part of the antenna ground plane for antenna  40 . 
     Near-field-coupled antenna feed structure  202  is near-field coupled to antenna slot  206  of slot antenna  40  by near-field electromagnetic signals and forms an indirect antenna feed for antenna  40 . During operation, transceiver circuitry  90  can transmit and receive wireless radio-frequency antenna signals with antenna  40  (i.e., with slot  206 ) using coupled feed structure  202 . 
     With a slot antenna structure such as slot antenna  40 , antenna currents are largest near closed slot end  208  and antenna voltages (and antenna electric field strengths) for antenna signals are lowest near end  208 . Antenna currents are minimized near open slot end  218 . Antenna voltages (and antenna electric field strengths) are maximized near open slot end  218 . To enhance antenna efficiency and antenna bandwidth, it may be desirable to provide slot antenna  40  with a locally widened slot width at end  218  (i.e., at the portion of slot antenna  40  where antenna signal voltages and electric fields are largest). As shown in  FIG. 16 , for example, a notch such as notch  330  may be formed in metal layers L 1  and L 2  at end  218  to locally widen slot  206 . 
     The metal traces that form layers L 1  and L 2  may be formed as metal layers on one or more flexible printed circuits or may be formed on other suitable substrates (e.g., plastic carriers, etc.). As an example, layer L 1  may be formed from metal traces on a first side of a flexible printed circuit and layer L 2  may be formed from metal traces on an opposing second side of the flexible printed circuit. As another example, layer L 1  may be formed from metal traces on the interior surface of antenna window  230  and layer L 2  may be formed on a dielectric support such as a flexible printed circuit. 
     A cross-sectional side view of antenna  40  of  FIG. 16  taken along line  336  and viewed in direction  338  of  FIG. 16  is shown in  FIG. 17 . As shown in  FIG. 17 , antenna  40  may include near-field-coupled antenna feed structure  202  having metal patch  212  and leg  214 . Antenna slot  206  may be indirectly fed using structure  202 . Patch  212  may overlap slot  206 . Slot  206  may be a dielectric gap formed between opposing antenna ground structures such as metal housing  12  and conductive structures  232 . Conductive structures  232  may be supported by antenna window  230  (e.g., a plastic antenna window) and may include lower metal layer L 1  and upper metal layer L 2  separated by dielectric layer  340  (e.g., a layer of polyimide or other flexible printed circuit substrate material, etc.). 
     Layers L 1  and L 2  serve as capacitive electrodes in a capacitive proximity sensor. Proximity sensor circuitry  320  may be coupled to layers L 1  and L 2  using inductors  344 ,  342 ,  343 , and  345 . The presence of inductors  344  and  342  prevents high frequency antenna signals from reaching proximity sensor circuitry  320 , so that proximity sensor circuitry  320  can make capacitive proximity sensor measurements without interference from antenna operations. Any suitable choke circuitry may be interposed in the paths coupling proximity sensor circuitry  320  to layers L 1  and L 2 . In the example of  FIG. 17 , inductors  342  and  343  are coupled in series between proximity sensor circuitry  320  and layer L 2 , whereas inductors  344  and  345  are coupled in series between proximity sensor circuitry  320  and layer L 1 . Inductors  342  and  344  may have smaller inductance values (e.g., about 200 nH) to choke high band antenna signals (e.g., signals from 1710-2700 MHz), whereas inductors  343  and  345  may have larger inductance values (e.g., about 300 nH) to chock low band antenna signals (e.g., 700-960 MHz). Additional filter circuitry may be used if desired (e.g., band stop filters including resistors, capacitors, inductors, and/or other circuitry). The example of  FIG. 17  is merely illustrative. 
     Capacitor  349  may be interposed in the path between layer L 2  and ground  347  (e.g., housing  12 ) to couple L 2  to ground  347 . For example, capacitor  349  may form part of a signal path on tab  234  of  FIG. 16  (as an example). Capacitor  349  may have a value of 50 pF or other suitable value. During proximity sensor operations, capacitor  349  forms an open circuit that prevents proximity sensor circuitry  320  from being improperly shorted. During antenna operations, capacitor  349  shorts layers L 1  and L 2  to ground  347  (i.e., to housing  12 ), so that layers L 1  and L 2  serve as part of the antenna ground plane for slot antenna  40 . Metal housing  12  on the opposing side of slot  206  serves as the other part of the antenna ground plane. Slot antenna  40  may have feed terminals  98  and  100 . Feed terminal  100  may be connected to metal housing  12 . Feed terminal  98  may be coupled to leg  214  of structure  202 . Transmission line  92  may have path  94  for coupling terminal  98  to transceiver circuitry  90  and may have path  96  for coupling feed terminal  100  to transceiver circuitry  90 . Transceiver circuitry  90  may include wireless circuitry such as transceiver  300  and power amplifier  302  of  FIG. 15 . 
       FIG. 18  is a cross-sectional side view of an edge portion of device  10  in the vicinity of an illustrative slot antenna. As shown in  FIG. 18 , slot antenna  40  may be formed from antenna slot  206  between metal housing  12  and conductive structures  232  overlapping antenna window  230 . Display  346  may overlap antenna structures  40 . Display  346  may include display structures such as a liquid crystal display module or an organic light-emitting display module and/or display cover layer structures such as a clear layer of glass or plastic. Antenna window  230  may have a shape with vertical sidewalls and a horizontal planar rear surface or may have a curved wall shape of the type shown in  FIG. 18 . Conductive structures  232  may have a curved shape to accommodate the curved surface on the interior of antenna window  230 . 
     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: 20140320
Publication Date: 20170131
Grant Date: 20170131
Priority Date: 20140320
Inventors: ZHU JIANG
GOMEZ ANGULO RODNEY A.
LI QINGXIANG
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/2266", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q13/10", "inventive": true, "first": true, "tree": "[]"}, {"code": "G01V3/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/2266", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1613", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q13/10", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q13/10", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/1613", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/2266", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1613", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01V3/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01V3/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1613", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/2266", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q13/10", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 52597314