PATENT DOCUMENT

Publication Number: US-9768491-B2
Application Number: US-201514691304-A
Country: US
Kind Code: B2

Title: Electronic device with peripheral hybrid antenna

Abstract:
An electronic device may have wireless circuitry with antennas. An antenna resonating element arm for an antenna may be formed from peripheral conductive structures running along the edges of a device housing. Elongated conductive members may longitudinally divide openings between the peripheral conductive housing structures and the ground. The elongated conductive members may extend from an internal ground to outer ends of the elongated conductive members that are located adjacent to the gaps. Transmission lines may extend along the elongated conductive members to antenna feeds at the outer ends. The elongated conductive members may form open slots that serve as slot antenna resonating elements for the antenna.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a housing having peripheral conductive structures; 
 an antenna that has an antenna resonating element arm formed from the peripheral conductive structures, that has an antenna ground that is separated from the antenna resonating element arm by an elongated opening that runs along at least one edge of the housing, and that has an elongated conductive member within the elongated opening that forms an open slot between the elongated conductive member and the antenna ground; 
 a first pair of antenna feed terminals and a first transmission line that are coupled to the antenna and that convey radio-frequency signals for the open slot and a first portion of the antenna resonating element arm; and 
 a second pair of antenna feed terminals and a second transmission line that are coupled to the antenna and that convey radio-frequency signals for a second portion of the antenna resonating element arm. 
 
     
     
       2. The electronic device defined in  claim 1  wherein the elongated conductive member has opposing first and second ends, the antenna ground has a portion from which the first end of the elongated conductive member extends and that forms a closed end for the open slot, and the open slot has an opposing open end at the second end of the elongated conductive member. 
     
     
       3. The electronic device defined in  claim 2  wherein the first pair of antenna feed terminals is located at the second end of the elongated conductive member. 
     
     
       4. The electronic device defined in  claim 3  wherein the peripheral conductive structures have at least one gap that separates the first portion of the antenna resonating element arm from the antenna ground and the antenna resonating element arm has an end at the gap. 
     
     
       5. The electronic device defined in  claim 4  wherein the first pair of antenna feed terminals includes a ground antenna feed terminal on the second end of the elongated conductive member. 
     
     
       6. The electronic device defined in  claim 5  wherein the first pair of antenna feed terminals includes a positive antenna feed terminal on the end of the antenna resonating element arm adjacent to the gap. 
     
     
       7. The electronic device defined in  claim 6  further comprising:
 radio-frequency transceiver circuitry, wherein the first transmission line extends along the elongated conductive member between the radio-frequency transceiver circuitry and the first pair of antenna feed terminals. 
 
     
     
       8. The electronic device defined in  claim 7  further comprising at least one electrical component that is coupled to the antenna resonating element arm. 
     
     
       9. The electronic device defined in  claim 8  wherein the elongated conductive member is separated from the antenna resonating element arm by a slot-shaped opening and the electrical component is coupled across the slot-shaped opening. 
     
     
       10. The electronic device defined in  claim 9  wherein the electrical component comprises a tunable inductor. 
     
     
       11. The electronic device defined in  claim 10  further comprising a fixed inductor that is coupled across the slot-shaped opening. 
     
     
       12. The electronic device defined in  claim 11  further comprising:
 an additional gap in the peripheral conductive structures, wherein the second portion of the antenna resonating element arm is separated from the antenna ground by an additional elongated opening; and 
 an additional elongated conductive member that longitudinally divides the additional elongated opening and that forms an additional open slot for the antenna. 
 
     
     
       13. The electronic device defined in  claim 12  wherein the second transmission line extends along the additional elongated conductive member from the transceiver circuitry to the second pair of antenna feed terminals, and the second pair of antenna feed terminals is coupled between the additional elongated conductive member and an end of the second portion of the antenna resonating element arm that is adjacent to the additional gap. 
     
     
       14. An electronic device, comprising:
 a rectangular housing having four edges and peripheral conductive structures that run along at least some of the edges; 
 first and second gaps in the peripheral conductive structures that define an antenna resonating element arm for an antenna; 
 an antenna ground for the antenna; 
 first and second elongated conductive members that extend respectively within first and second elongated openings that are formed between the antenna ground and the antenna resonating element arm, wherein the first and second elongated conductive members have respective outer ends; 
 a first antenna feed that is coupled between the outer end of the first elongated conductive member and the antenna resonating element arm adjacent to the first gap; and 
 a second antenna feed that is coupled between the outer end of the second elongated conductive member and the antenna resonating element arm adjacent to the second gap. 
 
     
     
       15. The electronic device defined in  claim 14  wherein the first and second elongated openings form part of a U-shaped opening that extends around three of the edges. 
     
     
       16. The electronic device defined in  claim 15  wherein the three edges include a lower edge of the housing and the antenna ground has a protruding portion adjacent to the lower edge from which the first and second elongated conductive members extend. 
     
     
       17. The electronic device defined in  claim 16  further comprising:
 radio-frequency transceiver circuitry; and 
 first and second transmission lines coupled to the radio-frequency transceiver circuitry and respectively extending along the first and second elongated conductive members to the first and second antenna feeds. 
 
     
     
       18. The electronic device defined in  claim 17  wherein a first open slot for the antenna is formed between the first elongated conductive member and the antenna ground and a second open slot for the antenna is formed between the second elongated conductive member and the antenna ground. 
     
     
       19. The electronic device defined in  claim 18  wherein the antenna is configured to exhibit a first resonance associated with the first open slot, a second resonance associated with the second open slot, a third antenna resonance associated with a first portion of the antenna resonating element arm, and a fourth resonance associated with a second portion of the antenna resonating element arm. 
     
     
       20. A cellular telephone, comprising:
 a housing having peripheral conductive structures that are separated from a ground by a U-shaped opening, wherein the ground forms part of an antenna; 
 first and second gaps in the peripheral conductive structures at opposing ends of the U-shaped opening, wherein a portion of the peripheral conductive structures forms an antenna resonating element arm for the antenna and the first and second gaps form first and second respective ends of the antenna resonating element arm; and 
 first and second elongated conductive structures that longitudinally bisect respective first and second portions of the U-shaped opening, wherein the first and second elongated conductive structures and the antenna ground form first and second respective open slots that serve as first and second slot antenna resonating elements for the antenna; 
 an antenna feed coupled between an end of the first elongated conductive structure and the antenna resonating element arm; and 
 a transmission line that extends along the first elongated conductive structure to the antenna feed. 
 
     
     
       21. The cellular telephone defined in  claim 20  further comprising:
 an additional antenna feed coupled between an end of the second elongated conductive structure and the antenna resonating element arm; 
 an additional transmission line that extends along the second elongated conductive member to the second antenna feed.

Description:
BACKGROUND 
     This relates generally to electronic devices and more particularly, to electronic devices with wireless communications circuitry. 
     Electronic devices often include wireless circuitry with 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 structures such as 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. 
     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 have wireless circuitry with antennas. The device may have a housing such as a rectangular housing with four edges. The housing may have conductive structures such as peripheral conductive structures that run along the edges of the housing. 
     Antennas may be formed from openings between peripheral conductive housing structures and an internal ground. The openings may extend along one or more of the edges of the housing. For example, an antenna may be formed using a U-shaped opening that runs along the edges of one of the ends of a rectangular device housing. 
     An antenna resonating element arm for an antenna may be formed from a portion of the peripheral conductive structures that extends between gaps in the peripheral conductive structures. Elongated conductive members may longitudinally divide portions of the U-shaped opening between the peripheral conductive housing structures and the ground. The elongated conductive members may extend from a portion of the ground to outer ends located adjacent to the gaps. 
     Transmission lines may extend along the elongated conductive members to antenna feeds at the outer ends. The antenna feeds may each have a ground terminal coupled to one of the outer ends and a positive terminal coupled to a portion of the antenna resonating element arm adjacent to one of the gaps. The elongated conductive members may form open slots that serve as slot antenna resonating elements for the antenna. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative electronic device in accordance with an embodiment. 
         FIG. 2  is a schematic diagram of illustrative circuitry in an electronic device in accordance with an embodiment. 
         FIG. 3  is a schematic diagram of illustrative wireless circuitry in accordance with an embodiment. 
         FIG. 4  is a schematic diagram of an illustrative inverted-F antenna in accordance with an embodiment. 
         FIG. 5  is a schematic diagram of an illustrative slot antenna in accordance with an embodiment of the present invention. 
         FIG. 6  is a diagram of illustrative antenna structures and antenna feeds in accordance with an embodiment. 
         FIG. 7  is a diagram of an illustrative hybrid inverted-F slot antenna in accordance with an embodiment. 
         FIG. 8  is a diagram of an illustrative matching circuit and antenna feed configuration of the type that may be used in feeding an antenna of the type shown in  FIG. 7  in accordance with an embodiment. 
         FIG. 9  is a graph in which antenna performance (standing-wave ratio) has been plotted as a function of operating frequency for an illustrative electronic device antenna in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices such as electronic device  10  of  FIG. 1  may be provided with wireless communications circuitry. The wireless communications circuitry may be used to support wireless communications in multiple wireless communications bands. 
     The wireless communications circuitry may include one more antennas. The antennas of the wireless communications circuitry can include loop antennas, inverted-F antennas, strip antennas, planar inverted-F antennas, slot antennas, hybrid antennas that include antenna structures of more than one type, or other suitable antennas. Conductive structures for the antennas may, if desired, be formed from conductive electronic device structures. 
     The conductive electronic device structures may include conductive housing, structures. The housing structures may include peripheral structures such as peripheral conductive structures that run around the periphery of an electronic device. The peripheral conductive structure may serve as a bezel for a planar structure such as a display, may serve as sidewall structures for a device housing may have portions that extend upwards from an integral planar rear housing (e.g., to form vertical planar sidewalls or curved sidewalls), and/or may form other housing structures. 
     Gaps may be formed in the peripheral conductive structures that divide the peripheral conductive structures into peripheral segments. One or more of the segments may be used in forming one or more antennas for electronic device  10 . Antennas may also be formed using an antenna ground plane formed from conductive housing structures such as metal housing midplate structures and other internal device structures. Rear housing wall structures may be used in forming antenna structures such as an antenna ground. 
     Electronic device  10  may be a portable electronic device or other suitable electronic device. For example, electronic device  10  may be a laptop computer, a tablet computer, a somewhat smaller device such as a wrist-watch device, pendant device, headphone device, earpiece device, or other wearable or miniature device, a handheld device such as a cellular telephone, a media player, or other small portable device. Device  10  may also be a television, a set-top box, a desktop computer, a computer monitor into which a computer has been integrated, 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. 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 . The rear face of housing  12  may have a planar housing wall. The rear housing wall may be separated into first and second portions by a gap that is filled with plastic or other dielectric. Conductive structures may electrically couple the first and second portions together. Display  14  may be mounted on the opposing front face of device  10  from the rear housing wall. Display  14  may be a touch screen that incorporates capacitive touch electrodes or may be insensitive to touch. 
     Display  14  may include pixels formed from light-emitting diodes (LEDs) organic LEDs (OLEDs), plasma cells, electrowetting pixels electrophoretic pixels, liquid crystal display (LCD) components, or other suitable pixel structures. A display cover layer such as a layer of clear glass or plastic May cover the surface of display  14  or the outermost layer of display  14  may be formed from a color filter layer, thin-film transistor layer or other display layer. Buttons such as button  24  may pass through openings in the cover layer. The cover layer May also have other openings such as an opening, for speaker port  26 . 
     Housing  12  may include peripheral housing structures such as structures  16 . Structures  16  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 structures  16  may be implemented using peripheral housing structures that have a rectangular ring shape with four corresponding edges (as an example). Peripheral structures  16  or part of peripheral structures  16  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 ). Peripheral structures  16  may also if desired form sidewall structures for device  10  (e.g., by forming a metal band with vertical sidewalls, curved sidewalls, etc.). 
     Peripheral housing structures  16  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, or a peripheral conductive housing member (as examples). Peripheral housing structures  16  may be formed from a metal such as stainless steel, aluminum, or other suitable materials. One two, or more than two separate structures may be used in forming peripheral housing structures  16 . 
     It is not necessary for peripheral housing structures  16  to have a uniform cross-section. For example, the top portion of peripheral housing structures  16  may, if desired, have an inwardly protruding lip that helps hold display  14  in place. The bottom portion of peripheral housing structures  16  may also have an enlarged lip (e.g., in the plane of the rear surface of device  10 ). Peripheral housing structures  16  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 housing structures  16  serve as a bezel for display  14 ), peripheral housing structures  16  may run around the lip of housing  12  (i.e., peripheral housing structures  16  may cover only the edge of housing  12  that surrounds display  14  and not the rest of the sidewalls of housing  12 ). 
     If desired, housing  12  may have a conductive rear surface. For example, housing  12  may be formed from a metal such as stainless steel or aluminum. The rear surface of housing  12  may lie in a plane that is parallel to display  14 . In configurations for device  10  in which the rear surface of housing  12  is formed from metal, it may be desirable to form parts of peripheral conductive housing structures  1  as integral, portions of the housing structures forming the rear surface of housing  12 . For example, a rear housing wall of device  10  may be formed from a planar metal structure and portions of peripheral housing structures  16  on the sides of housing  12  may be formed as vertically extending integral metal portions of the planar metal structure. 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 . The planar rear wall of housing  12  may have one or more two or more, or three or more portions. 
     Display  14  may have an array of pixels that form an active area AA that displays images for a user of device  10 . An inactive border region such as inactive area  1 A may run along one or more of the peripheral edges of active area AA. 
     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 midplate) that spans the walls of housing  12  (i.e., a substantially rectangular sheet formed from one or more parts that is welded or otherwise connected between opposing sides of member  16 ). Device  10  may also include conductive structures such as printed circuit boards, components mounted on printed circuit hoards, and other internal conductive structures. These conductive structures, which may be used in forming a ground plane in device  10 , may be located in the center of housing  12  and may extend under active area AA of display  14 . 
     In regions  22  and  20 , openings may be formed within the conductive structures of device  10  (e.g., between peripheral conductive housing structures  16  and opposing conductive ground structures such as conductive housing midplate or rear housing wall structures, a printed circuit board, and conductive electrical components in display  14  and device  10 ). These openings, which may sometimes be referred to as gaps, may be filled with air plastic, and other dielectrics and may be used in forming slot antenna resonating elements for one or more antennas in device  10 . 
     Conductive housing structures and other conductive structures in device  10  such as a midplate, traces on a printed circuit board, display  14 , and conductive electronic components may serve as a ground plane for the antennas in device  10 . The openings in regions  20  and  22  may serve as slots in open or closed slot antennas, may serve as a central dielectric region that is surrounded by a conductive path of materials in a loop antenna, may serve as a space that separates an antenna resonating element such as a strip antenna resonating element or an inverted-F antenna resonating element from the ground plane, may contribute to the performance of a parasitic antenna resonating element, or may otherwise serve as part of antenna structures formed in regions  20  and  22 . If desired the ground plane that is under active area AA of display  14  and/or other metal structures in device  10  may have portions that extend into parts of the ends of device  10  (e.g., the ground may extend towards the dielectric-filled openings in regions  20  and  22 ), thereby narrowing the slots in regions  20  and  22 . In configurations for device  10  with narrow U-shaped openings or other openings that run along the edges of device  10 , the ground plane of device  10  can be enlarged to accommodate additional electrical components (integrated circuits, sensors, etc.) 
     In general, device  10  may include any suitable number of antennas (e.g., one or more, two or more, three or more, four or more, etc.). The antennas in device  10  may be located at opposing first and second ends of an elongated device housing (e.g., at ends  20  and  22  of device  10  of  FIG. 1 ), along one or more edges of a device housing, in the center of a device housing, in other suitable locations, or in one or more of these locations. The arrangement of  FIG. 1  is merely illustrative. 
     Portions of peripheral housing structures  16  may be provided with peripheral gap structures. For example, peripheral conductive housing structures  16  may be provided with one or more gaps such as gaps  18 , as shown in  FIG. 1 . The gaps in peripheral housing structures  16  may be filled with dielectric such as polymer, ceramic, glass, air, other dielectric materials, or combinations of these materials. Gaps  18  may divide peripheral housing structures  16  into one or more peripheral conductive segments. There may be, for example two peripheral conductive segments in peripheral housing structures  16  (e.g., in an arrangement with two of gaps  18 ), three peripheral conductive segments (e.g., in an arrangement with three of gaps  18 ), four peripheral conductive segments (e.g., in an arrangement with four gaps  18 , etc.). The segments of peripheral conductive housing structures  16  that are formed in this way may form parts of antennas in device  10 . 
     If desired, openings in housing  12  such as grooves that extend partway or completely through housing  12  may extend across the width of the rear wall of housing  12  and may penetrate through the rear wall of housing  12  to divide the rear wall into different portions. These grooves may also extend into peripheral housing structures  16  and may form antenna slots gaps  18 , and other structures in device  10 . Polymer or other dielectric may fill these grooves and other housing openings. In some situations, housing openings that form antenna slots and other structure may be filled with a dielectric such as air. 
     In a typical scenario, device  10  may have upper and lower antennas as an example). An upper antenna may for example, be formed at the upper end of device  10  in region  22 . A lower antenna may for example be formed at the lower end of device  10  in region  20 . The antennas may be used separately to cover identical communications bands, overlapping communications bands, or separate communications bands. The antennas may be used to implement an antenna diversity scheme or a multiple-input-multiple-output (MIMO) antenna scheme. 
     Antennas in device  10  may be used to support any communications bands of interest. For example, device  10  may include antenna structures for supporting local area network communications, voice and data cellular telephone communications, global positioning system (GPS) communications or other satellite navigation system communications, Bluetooth® communications, etc. 
     A schematic diagram showing illustrative components that may be used in device  10  of  FIG. 1  is shown in  FIG. 2 . As shown in  FIG. 2  device  10  may include control circuitry such as storage and processing circuitry  28 . Storage and processing circuitry  28  may include storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid state drive) volatile memory (e.g., static or dynamic random-access-memory), etc. Processing circuitry in storage and processing circuitry  28  may be used to control the operation of device  10 . This processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors application specific integrated circuits, etc. 
     Storage and processing circuitry  28  may be used to run software on device  10  such a 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 protocols for other short-range wireless communications links such as the Bluetooth® protocol, cellular telephone protocols, multiple-input and multiple-output (MIMO) protocols, antenna diversity protocols, etc. 
     Input-output circuitry  30  may include input-output devices  32 . Input-output devices  32  may be used to allow data to be supplied to device  10  and to allow data to be provided from device  10  to external devices. Input-output devices  32  may include use interface devices, data port devices, and other input-output components. For example, input-output devices  32  may include touch screens, displays without touch sensor capabilities, buttons joysticks, scrolling wheels, touch pads, key pads, keyboards, microphones, cameras, buttons, speakers, status indicators, light sources, audio jacks and other audio port components, digital data port devices, light sensors, motion sensors accelerometers), capacitance sensors, proximity sensors, fingerprint sensors (e.g., a fingerprint sensor integrated with a button such as button  24  of  FIG. 1  or a fingerprint sensor that takes the place of button  24 ), etc. 
     Input-output circuitry  30  may include wireless communications circuitry  34  for communicating wirelessly with external equipment. Wireless communications circuitry  34  may include radio-frequency (RF) transceiver circuitry formed from one or more integrated circuits, power amplifier circuitry, low-noise input amplifiers, passive RF components, one or more antennas, transmission lines, and other circuitry for handling RF wireless signals. Wireless signals can also be sent using light (e.g., using infrared communications). 
     Wireless communications circuitry  34  may include radio-frequency transceiver circuitry  90  for handling various radio-frequency communications bands. For example, circuitry  34  may include transceiver circuitry  36 ,  38 , and  42 . Transceiver circuitry  36  may handle 2.4 GHz and 5 GHz bands for WiFi® (IEEE 802.11) communications and 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 low-midband from 1400-1520 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 (NEC) circuitry, etc. Wireless communications circuitry  34  may include global positioning system ((GPS) receiver equipment such as GPS receiver circuitry  42  for receiving GPS signals at 1575 MHz or for handling other satellite positioning data. 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. 3 , 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 such as antenna(s)  40  with the ability to cover communications frequencies of interest, antenna(s)  40  may be provided with circuitry such as filter circuitry (e.g., one or more passive filters and/or one or more tunable filter circuits). Discrete components such as capacitors, inductors, and resistors may be incorporated into the filter circuitry. Capacitive structures, inductive structures, and resistive structures may also be formed from patterned metal structures (e.g., part of an antenna). If desired, antennas)  40  may be provided with adjustable circuits such as tunable components  102  to tune antennas over communications bands of interest. Tunable components  102  may be part of a tunable filter or tunable impedance matching network, may be part of an antenna resonating element, may span a gap between an antenna resonating element and antenna ground, etc. Tunable components  102  may include tunable inductors tunable capacitors, or other tunable components. Tunable components such as these may be based on switches and networks of fixed components, distributed metal structures that produce associated distributed capacitances and inductances, variable solid state devices for producing variable capacitance and inductance values, tunable filters, or other suitable tunable structures. During operation of device  10 , control circuitry  28  may issue control signals on one or more paths such as path  120  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. 3  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(s)  40  to the impedance of transmission line  92 . Matching network components may be provided as discrete components (e.g., surface mount technology components) or may membered from housing structures, printed circuit hoard structures, traces on plastic supports, etc. Components such as these may also be used in forming filter circuitry in antenna(s)  40  and may be tunable and/or fixed components. 
     Transmission line  92  may be coupled to antenna feed structures associated with antenna structures  40 . As an example, antenna structures  40  may form an inverted-F antenna a slot antenna, a hybrid inverted-F slot antenna or other antenna having an antenna feed with a positive antenna feed terminal such as terminal  98  and a ground antenna feed terminal such as ground antenna feed terminal  100 . Positive transmission line conductor  94  may be coupled to positive antenna feed terminal  98  and ground, transmission line conductor  96  may be coupled to ground antenna feed terminal  92 . Other types of antenna feed arrangements may be used if desired. For example, antenna structures  40  may be fed using multiple feeds. The illustrative feeding configuration of  FIG. 3  is merely illustrative. 
     Control circuitry  28  may use an impedance measurement circuit to gather antenna impedance information. Control circuitry  28  may use information from a proximity sensor (see, e.g., sensors  32  of  FIG. 2 ), received signal strength information, information from one or more antenna impedance sensors, or other information in determining when antenna  40  is being affected by the presence of nearby external objects or is otherwise in need of tuning. In response, control circuitry  28  may adjust an adjustable inductor or other tunable component  102  to ensure that antenna  40  operates as desired. Adjustments to component  102  may also be made to extend the coverage of antenna  40  (e.g., to cover desired communications bands that extend over a range of frequencies larger than antenna  40  would cover without tuning). 
       FIG. 4  is a diagram of illustrative inverted-F antenna structures that may be used in implementing antenna  40  for device  10 . Inverted-F antenna  40  of  FIG. 4  has antenna resonating element  106  and antenna around (ground plane)  104 . Antenna resonating element  106  may have a main resonating element arm such as arm  108 . The length of arm  108  and/or portions 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 around  104  by return path  110 . An inductor or other component may be interposed in path  110  and/or tunable components  102  may be interposed in path  110  and/or coupled in parallel with path  110  between arm  108  and around  104 . 
     Antenna  40  may be fed using one or more antenna feeds. For example, antenna  40  may be fed using antenna feed  112 . Antenna feed  112  may include positive antenna feed terminal  98  and around antenna feed terminal  100  and may run in parallel to return path  110  between arm  108  and around  104 . Antenna  40  may also be feed by a feed that is located at the end of arm  108  such as feed  112 ′. Feed  112 ′ include positive antenna feed terminal  98 ′ coupled to arm  108  and round antenna feed  100 ′ coupled around  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.). For example arm  108  may have left and right branches that extend outwardly from feed  112  and return path  110 . Multiple feeds may be used to feed antennas such as antenna  40 . 
     Antenna  40  may be a hybrid antenna that includes one or more slot antenna resonating elements. As shown in  FIG. 5  for example antenna  40  may be based on a slot antenna configuration having an opening such as slot  114  that is formed within antenna ground  104 . Slot  114  may be filled with air, plastic, and/or other dielectric. The shape of slot  114  may be straight or may have one or more bends (i.e., slot  114  may have an elongated shape following a meandering path). The antenna feed for antenna  40  may include positive antenna feed terminal  98  and around antenna feed terminal  100 . Feed terminals  98  and  100  may for example, be located on opposing sides of slot  114  (e.g., on opposing long sides). Slot-based antenna resonating elements such as slot antenna resonating element  114  of  FIG. 5  may give rise to an antenna resonance at frequencies in which the wavelength of the antenna signals is equal to the perimeter of the slot. In narrow slots, the resonant frequency of a slot antenna resonating element is associated with signal frequencies at which the slot length is equal to a half of as wavelength. Slot antenna frequency response can be tuned using one or more tunable components such as tunable inductors or tunable capacitors. These components may have terminals that are coupled to opposing sides of the slot (i.e., the tunable components may bridge the slot). If desired, tunable components may have terminals that are coupled to respective locations along the length of one of the sides of slot  114 . Combinations of these arrangements may also be used. 
     Antenna  40  may be a hybrid slot-inverted-F antenna that includes resonating elements of the type shown in both  FIG. 4  and  FIG. 5 . An illustrative feeding arrangement for a hybrid antenna of this type is shown in  FIG. 6 . As shown in  FIG. 6 , hybrid antenna  40  (e.g., a hybrid slot-inverted-F antenna) may be fed by transceiver circuitry  90  using a first feed such as feed F 1  and a second feed such as feed F 2 . Transceiver circuitry  90  may have a first port that is coupled to feed F 1  using transmission line  92 - 1  and a second port that is coupled to feed F 2  using transmission line  92 - 2 . If desired tunable and/or fixed impedance matching circuits such as matching circuits M 1  and M 2  may be interposed in paths  92 - 1  and  92 - 2 . Additional antenna structures such as antenna  40  (e.g., example elements or other types of antennas) may be fed using transceiver circuitry  90  and may help enhance the frequency coverage of antenna  40 . In the example of  FIG. 6 , antenna  40 ′ is feed at feed F 3  by coupling a third port of circuitry  90  to antenna  40  using transmission line  92 - 3 , but other feeding arrangements may be used if desired (e.g., a feeding arrangement in which one of feeds F 1  and F 2  is used in feeding, element  40 ). A matching circuit may be interposed in path  92 - 3 , if desired. Antenna  40 ′ may be used to provide local wireless local area network coverage at 2.4 and/or 5 GHz while antenna  40  is used to cover satellite navigation and cellular bands and/or antenna  40 ′ may be used to provide coverage in other suitable frequency bands. If desired, additional antenna element  40 ′ may be omitted or more than one additional element such as element  40 ′ may be included in device  10 . Antenna elements such as antenna element  40 ′ may be located at ends  20  and/or  22  or elsewhere in device  10 . 
     An interior view of device  10  showing an illustrative configuration that may be used for a dual-feed hybrid antenna is shown in  FIG. 7 . As shown in  FIG. 7 , antenna  40  may have an inverted-F antenna resonating element arm such as arm  108  formed from peripheral conductive structures  16 . Arm  108  has a first end that is separated from ground plane  104  at gap  18 - 1  and a second end that is separated, from ground plane  104  at gap  18 - 2 . An elongated, opening may separate arm  108  from ground plane  104 . The elongated opening may have a U-shape that runs along three peripheral edges of device  10  or may have other shapes. Antenna arm  108  may have a first branch such as branch A 1  and a second branch such as branch A 2 . The end of branch A 1  at feed F 1  may be fed using positive antenna feed terminal  98 - 1  and ground antenna feed terminal  100 - 1 . The end of branch A 2  (i.e., the opposing end of arm  108 ) at feed F 2  may be fed using positive antenna feed terminal  98 - 2  and ground antenna feed terminal  100 - 2 . 
     A central portion of ground plane  104  may extend downwards to form ground plane protrusion  104 ′. Ground plane protrusion  104 ′ may branch out to form two opposing elongated (strip-shaped) conductive members: conductive member  142 - 1  and conductive member  142 - 2 . Conductive members  142 - 1  and  142 - 2  may be formed from machined metal portions of housing  12 , metal traces on a plastic support structures (e.g., traces patterned using laser direct structuring techniques in which portions of a plastic support are selectively activated by exposure to laser light to promote localized metal plating during subsequent electroplating operations) stamped metal foil, wire, or other elongated conductive structures. Structures such as conductive members  142 - 1  and  142 - 2  may be supported by plastic that is molded into the opening between arm  108  and ground plane  104 , may be supported on a printed circuit or other substrate, or may be partly or full) suspended in an between arm  108  and ground plane  104 . 
     Radio-frequency transceiver circuitry  90  may be coupled to antenna feeds F 1  and  12  at the outer ends of elongated conductive members  142 - 1  and  142 - 2  using respective transmission lines such as transmission lines  92 - 1  and  92 - 2 . Transmission line  92 - 1  may include positive signal path  94 - 1  and associated ground signal conductor  96 - 1 . Transmission line  92 - 2  may include positive signal path  94 - 2  and ground signal path  96 - 2 . Transmission lines  92 - 1  and  92 - 1  extend along respective elongated members  142 - 1  and  142 - 2  and couple transceiver circuitry  90  to respective feeds F 1  and F 2 . If desired, coaxial cables, flexible printed circuit cables, or other cables may be used in forming transmission lines  92 - 1  and  92 - 2 . For example, a first coaxial cable may run along member  142 - 1  and a second coaxial cable may run along member  142 - 2 . The center conductors of the first and second coaxial cables may form positive signal paths  94 - 1  and  94 - 2 . The outer conductors of the first and second coaxial cables may form ground signal paths  96 - 1  and  96 - 2  and may be shorted to respective ground feed terminals  100 - 1  and  100 - 2  at the ends of members  142 - 1  and  142 - 2 . If desired, the outer conductors of the cables may also be shorted to members  142 - 1  and  142 - 2  at one or more positions along the lengths of members  142 - 1  and  142 - 2 . Members  142 - 1  and  142 - 2  may be separate from the ground conductors in transmission lines  92 - 1  and  92 - 1  (i.e., members  142 - 1  and  142 - 2  may be separate from the outer ground conductor in the first and second coaxial cables) or members  142 - 1  and  142 - 2  may form some or all of ground signal paths  96 - 1  and  96 - 2 . 
     The opening between arm  108  and ground  104  may have a shape that runs along one or more edges of device  10 . In the example of  FIG. 7 , the opening between arm  108  and ground  104  has a U-shape that runs along a portion of the lower left edge of device  10 , the bottom edge of device  10 , and a portion of the lower right edge of device  10 . Ground protrusion  104 ′ laterally bisects this opening into left and right halves. The left half of the opening is bisected along its length the left opening is longitudinally divided) by member  142 - 1  to form openings  130 - 1 A and  130 - 1 B. The right half of the opening is bisected along its length the right opening is longitudinally divided) by member  142 - 2  to form openings  130 - 2 A and  130 - 2 B. Openings  130 - 1 A,  130 - 1 B,  130 - 2 A, and  130 - 2 B may have the shape of elongated strips and may sometimes be referred to as slot-shaped openings or slots. Slots such as open slots  130 - 1 A and  130 - 2 A may form slot antenna resonating elements that contribute to the frequency coverage of antenna  40 . The lengths of openings  130 - 1 A,  130 - 1 B,  130 - 2 A, and  130 - 2 B may be 1-20 cm, more than 3 cm, more than 7 cm, less than 30 cm, less than 20 cm, less than 10 cm, or other suitable lengths. The widths of openings  130 - 1 A,  130 - 1 B,  130 - 2 A, and  130 - 2 B  1  may be 0.5-5 mm, may be 1-3 mm, may be more than 0.2 mm, may be more than 1 mm, may be less than 3 mm, may be less than 6 mm, or may be any other suitable width. 
     Opening  130 - 1 A may have a closed end at the left side a ground protrusion  104 ′ and an opposing open end such as open end  144 - 1 . Opening  130 - 2 A may have a closed end at the right side of ground protrusion  104 ′ and an opposing open end such as open end  144 - 2 . Openings  130 - 1 A and  130 - 2 A may form first and second respective open-ended slots S 1  and S 2  (sometimes referred to as open slots or open slot resonating elements). In the illustrative configuration of  FIG. 7 , the open ends of slots S 1  and S 2  are not bridged by positive signal conductors  94 - 1  and  94 - 2 , because conductors  94 - 1  and  94 - 2  run along members  142 - 1  and  142 - 2  from ground protrusion  104 ′ and terminate at respective positive antenna feed terminals  98 - 1  and  98 - 2  on the opposing ends of arm  108 . 
     As shown in  FIG. 7 , components such as inductor  132  and tunable inductor  134  (or other tunable component  102 ) may span the gap ( 130 - 1 B and/or  130 - 2 B) between arm  108  and ground protrusion  104 ′ of ground  104 . Arm  108  may have branches such as arm A 1  and arm A 2 . Arm A 1  may extend between gap  18 - 1  at feed F 1  and components  132  and  134 . Arm A 2  may extend between gap  18 - 2  at feed F 2  and components  132  and  134 . Slots S 1  and S 2  and arms A 1  and A 2  form portions of a hybrid inverted-F slot antenna (antenna  40 ). The lengths of open slots S 1  and S 2  and the lengths of respective branches (arms) A 1  and A 2  of resonating element (arm)  108  may form antenna resonance peaks that help ensure that antenna  40  will operate it desired communications bands. 
       FIG. 8  shows how a cable such as coaxial cable  140  may run along member  142 - 2  (the arrangement for member  142 - 1  may be similar). In the example of  FIG. 8 , cable  140  has a center conductor that forms positive transmission line path  94 - 2  and an outer ground conductor that from ground transmission line path  96 - 2  (i.e., cable  140  of  FIG. 8  may form transmission line  92 - 2 ). At feed F 2 , positive transmission line path  94 - 2  extends across opening  130 - 2 B and is shorted to positive antenna feed terminal  98 - 2  at the end of arm A 2 . Impedance matching circuitry for feed F 2  (matching circuit M 2 ) may be formed from electrical components  148  mounted on substrate  146  (as an example). The impedance matching circuitry may be interposed in transmission line  92 - 2  and may be coupled to positive feed terminal  98 - 2  and ground feed terminal  100 - 2  (which is formed by terminating the ground conductor of path  92 - 2  at the outer end of member  142 - 2 ). Structures of the type shown in  FIG. 8  may be used for both feed F 2  and feed F 1 . The impedance matching circuitry may be fixed or may be tunable (see, e.g., tunable components  102 ). 
       FIG. 9  is a graph in which antenna performance (standing-wave ratio SWR) has been plotted as a function of operating frequency f for an illustrative antenna such as antenna  40  of  FIG. 7 . As shown in  FIG. 9 , antenna  40  may exhibit resonances in a low band LB, low-middle band LMB, midband MB, and high band HB. Low band LB may extend from 700 MHz to 960 MHz, low midband LMB may extend from 1400 MHz to 1520 MHz, midband MB may extend from 1700 MHz to 2200 MHz, and high band HB may extend from 2300 MHz to 2700 MHz (as examples). The resonance at low band LB may be associated with the length of arm A 2 . The resonance at low mid-band LMB may arise from the length of slot S 2 . The length of arm A 1  may give rise to the resonance at mid-band MB. The resonance at high band HB may be generated from the length of slot. S 1 . Higher-order resonances associated with the length of slot S 1  may support an antenna response at higher frequencies such as 5 GHz. If desired, an additional antenna structure such as antenna structure  40 ′ of  FIG. 6  (e.g., a monopole, etc.) may be used in supporting coverage at 5 GHz. 
     Antennas such as antenna  40  of  FIG. 7  may be formed at the lower end of device  10 , at the upper end of device  10 , at both the upper and lower ends of device  10 , or elsewhere in device  10 . Different ranges of frequencies may be covered by adjusting components  132  and  134  and/or the shapes of arms A 1  and A 2  and slots S 1  and S 2 . Slots S 1  and S 2  and arms A 1  and A 2  may be formed along one edge of device  10 , along two edges of device  10 , along three edges of device  10  (as shown in  FIG. 7 ), or along four edge of device  10  (as examples). The configuration of  FIG. 7  is merely illustrative. 
     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: 20150420
Publication Date: 20170919
Grant Date: 20170919
Priority Date: 20150420
Inventors: JIN NANBO
LAKSHMANAN ANAND
AYALA VAZQUEZ ENRIQUE
TONG ERICA J.
HU HONGFEI
MOW MATTHEW A.
PASCOLINI MATTIA
TSAI MING-JU
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q13/103", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/3888", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/50", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/48", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/28", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/28", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q13/103", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/3888", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/48", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/50", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 56027616