PATENT DOCUMENT

Publication Number: US-9147932-B2
Application Number: US-201213647106-A
Country: US
Kind Code: B2

Title: Tunable multiband antenna with dielectric carrier

Abstract:
Antenna structures for an antenna may be formed from a dielectric carrier with metal structures. The metal structures may be patterned to cover all sides of the dielectric carrier. The dielectric carrier may have a shape with six sides or other shape that creates a three-dimensional layout for the antenna structures. The antenna structures may have a tunable circuit that allows the antenna to be tuned. The tunable circuit may have first and second terminals coupled to one of the sides of the carrier. The metal structures may be configured to form an inverted-F antenna resonating element. Portions of the metal structures may form a first arm for an inverted-F antenna and portions of the metal structures may form a second arm for the inverted-F antenna. The antenna may operate in multiple communications bands. The tunable circuit may tune one band without significantly tuning other bands.

Claims:
What is claimed is: 
     
       1. An antenna, comprising:
 a dielectric carrier having at least five sides; 
 a conductor on the at least five sides that forms an antenna resonating element, wherein the conductor covers at least the five sides; and 
 positive and ground antenna feed terminals connected to the conductor. 
 
     
     
       2. The antenna defined in  claim 1  wherein the antenna resonating element has a first arm that is configured to exhibit a resonance in a first frequency band and a second arm that is longer than the first arm and that is configured to exhibit a resonance in a second frequency band that is lower than the first frequency band. 
     
     
       3. The antenna defined in  claim 2  further comprising tunable circuitry that is configured to tune the antenna. 
     
     
       4. The antenna defined in  claim 3  wherein the tunable circuitry is configured to tune the resonance in the second frequency band without tuning the resonance in the first frequency band. 
     
     
       5. The antenna defined in  claim 4  wherein the dielectric carrier has six sides and wherein the conductor covers at least part of each of the six sides. 
     
     
       6. The antenna defined in  claim 5  wherein the dielectric carrier is hollow. 
     
     
       7. The antenna defined in  claim 6  wherein the dielectric carrier has a body with cavities and a lid that is configured to attach to the body. 
     
     
       8. The antenna defined in  claim 1  wherein the first and second frequency bands comprise bands selected from the group consisting of: cellular telephone frequency bands and satellite navigation system bands. 
     
     
       9. The antenna defined in  claim 1  wherein the antenna resonating element comprises a dual-band inverted-F antenna resonating element. 
     
     
       10. The antenna defined in  claim 9  wherein the dielectric carrier comprises a plastic box. 
     
     
       11. The antenna defined in  claim 10  wherein the dielectric carrier has six sides. 
     
     
       12. The antenna defined in  claim 11  further comprising tuning circuitry having first and second terminals that are both coupled to the conductive traces on one of the six sides. 
     
     
       13. The antenna defined in  claim 12  wherein the tuning circuitry comprises a plurality of inductors and switches. 
     
     
       14. The antenna defined in  claim 1 , wherein the positive and ground antenna feed terminals are directly connected to the conductor at a given one of the at least five sides. 
     
     
       15. The antenna defined in  claim 1 , wherein the conductor completely covers at least four sides of the dielectric carrier. 
     
     
       16. The antenna defined in  claim 1 , wherein the conductor comprises a slot at a given side of the dielectric carrier. 
     
     
       17. The antenna defined in  claim 16 , wherein the conductor comprises an additional slot at the given side of the dielectric carrier. 
     
     
       18. The antenna defined in  claim 16 , wherein the conductor comprises an additional slot at an additional side of the dielectric carrier. 
     
     
       19. The antenna defined in  claim 1 , wherein the conductor comprises an electrically continuous conductor that covers at least five of the sides. 
     
     
       20. The antenna defined in  claim 1 , wherein the antenna is formed within an electronic device having a conductive housing and a dielectric window in the conductive housing, and the antenna is configured to radiate radio-frequency signals through the dielectric window in the conductive housing.

Description:
BACKGROUND 
     This relates generally to electronic devices, and, more particularly, to antennas in electronic devices. 
     Electronic devices such as portable computers and handheld electronic devices are becoming increasingly popular. Devices such as these are often provided with wireless communications capabilities. For example, electronic devices may have wireless communications circuitry to communicate using cellular telephone bands and to support communications with satellite navigation systems and local wireless area networks. 
     It can be difficult to incorporate antennas and other electrical components successfully into an electronic device. Some electronic devices are manufactured with small form factors, so space for components is limited. In many electronic devices, the presence of conductive structures can influence the performance of electronic components, further restricting potential mounting arrangements for components such as antennas. 
     It would therefore be desirable to be able to provide improved electronic device antennas. 
     SUMMARY 
     An electronic device may have an antenna. Antenna structures for the antenna may be formed from a dielectric carrier such as a hollow plastic carrier covered with metal structures. The metal structures may be patterned to cover the plastic carrier. 
     The plastic carrier may have a shape such as a box shape with sides that create a three-dimensional layout for the antenna structures. The carrier may be provided with cavities. 
     The antenna structures may be provided with a tunable circuit to allow the antenna to be tuned. The tunable circuit may include components such as capacitors or inductors and may be tuned by controlling the operation of switches or other adjustable circuitry. The tunable circuit may have first and second terminals coupled to one of the sides of the plastic carrier. 
     The metal structures may be configured to form an antenna resonating element for an inverted-F antenna. Portions of the metal structures may form a first arm for the inverted-F antenna and portions of the metal structures may form a second arm for the inverted-F antenna. The antenna may operate in multiple communications bands. The tunable circuit may tune one band without significantly tuning other bands. 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front perspective view of an illustrative electronic device of the type that may be provided with antenna structures in accordance with an embodiment of the present invention. 
         FIG. 2  is a rear perspective view of an illustrative electronic device such as the electronic device of  FIG. 1  in accordance with an embodiment of the present invention. 
         FIG. 3  is a diagram of antenna structures and associated circuitry in an electronic device in accordance with an embodiment of the present invention. 
         FIG. 4  is a circuit diagram of an illustrative tunable component based on a series-connected inductor and switch in accordance with an embodiment of the present invention. 
         FIG. 5  is a circuit diagram of an illustrative tunable component based on a series-connected capacitor and switch in accordance with an embodiment of the present invention. 
         FIG. 6  is a circuit diagram of an illustrative tunable component based on a parallel inductor and bypass switch in accordance with an embodiment of the present invention. 
         FIG. 7  is a circuit diagram of an illustrative tunable component based on a parallel capacitor and bypass switch in accordance with an embodiment of the present invention. 
         FIG. 8  is a circuit diagram of an illustrative tunable component based on a variable capacitor in accordance with an embodiment of the present invention. 
         FIG. 9  is a circuit diagram of an illustrative tunable component based on a variable inductor in accordance with an embodiment of the present invention. 
         FIG. 10  is a circuit diagram of an illustrative tunable component based on multiple components such as fixed and tunable components coupled in series and in parallel in accordance with an embodiment of the present invention. 
         FIG. 11  is a plot of antenna performance (standing-wave ratio) as a function of operating frequency for an illustrative tunable antenna having a tunable low band resonance and a fixed high band resonance in accordance with an embodiment of the present invention. 
         FIG. 12  is a cross-sectional side view of a portion of the electronic device of  FIGS. 1 and 2  in accordance with an embodiment of the present invention. 
         FIG. 13  is a diagram of an illustrative dual arm inverted-F antenna in accordance with an embodiment of the present invention. 
         FIG. 14  is a perspective view of an illustrative dual arm inverted-F antenna that has been implemented using traces on a three-dimensional dielectric carrier such as a box-shaped carrier with six sides in accordance with an embodiment of the present invention. 
         FIG. 15  is a top view of unwrapped metal structures from the illustrative antenna of  FIG. 14  in accordance with an embodiment of the present invention. 
         FIG. 16  is a perspective view of a dielectric carrier with air-filled cavities sealed by a lid in accordance with an embodiment of the present invention. 
         FIG. 17  is a cross-sectional side view of an illustrative antenna having a dielectric carrier coated with metal traces in accordance with an embodiment of the present invention. 
         FIG. 18  is a cross-sectional side view of an illustrative antenna having a dielectric carrier partly coated with metal traces and partly covered with traces in a flexible printed circuit in accordance with an embodiment of the present invention. 
         FIG. 19  is a cross-sectional side view of an illustrative antenna having a dielectric carrier wrapped in a flexible printed circuit in accordance with an embodiment of the present invention. 
         FIG. 20  is a cross-sectional side view of an illustrative antenna having a dielectric carrier partly coated with stamped metal foil structures in accordance with an embodiment of the present invention. 
         FIG. 21  is a cross-sectional side view of an illustrative antenna having a dielectric carrier with metal structures and a tunable circuit in accordance with an embodiment of the present invention. 
         FIG. 22  is a cross-sectional side view of a portion of an illustrative antenna having a dielectric carrier formed from multiple shots of plastic in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices may be provided with antennas, and other electronic components. An illustrative electronic device in which electronic components such as antenna structures may be used is shown in  FIG. 1 . As shown in  FIG. 1 , device  10  may have a display such as display  50 . Display  50  may be mounted on a front (top) surface of device  10  or may be mounted elsewhere in device  10 . Device  10  may have a housing such as housing  12 . Housing  12  may have curved, angled, or vertical sidewall portions that form the edges of device  10  and a relatively planar portion that forms the rear surface of device  10  (as an example). Housing  12  may also have other shapes, if desired. 
     Housing  12  may be formed from conductive materials such as metal (e.g., aluminum, stainless steel, etc.), carbon-fiber composite material or other fiber-based composites, glass, ceramic, plastic, or other materials. A radio-frequency-transparent window such as window  58  may be formed in housing  12  (e.g., in a configuration in which the rest of housing  12  is formed from conductive structures). Window  58  may be formed from plastic, glass, ceramic, or other dielectric material. Antenna structures, and, if desired, proximity sensor structures for use in determining whether external objects are present in the vicinity of the antenna structures may be formed in the vicinity of window  58  or may be covered with dielectric portions of housing  12 . 
     Device  10  may have user input-output devices such as button  59 . Display  50  may be a touch screen display that is used in gathering user touch input. The surface of display  50  may be covered using a display cover layer such as a planar cover glass member or a clear layer of plastic. The central portion of display  50  (shown as region  56  in  FIG. 1 ) may be an active region that displays images and that is sensitive to touch input. Peripheral portions of display  50  such as region  54  may form an inactive region that is free from touch sensor electrodes and that does not display images. 
     An opaque masking layer such as opaque ink or plastic may be placed on the underside of display  50  in peripheral region  54  (e.g., on the underside of the cover glass). This layer may be transparent to radio-frequency signals. The conductive touch sensor electrodes in region  56  may tend to block radio-frequency signals. However, radio-frequency signals may pass through the display cover layer (e.g., through a cover glass layer) and may pass through the opaque masking layer in inactive display region (as an example). Radio-frequency signals may also pass through antenna window  58  or dielectric housing walls in housing formed from dielectric material. Lower-frequency electromagnetic fields may also pass through window  58  or other dielectric housing structures, so capacitance measurements for a proximity sensor may be made through antenna window  58  or other dielectric housing structures, if desired. 
     With one suitable arrangement, housing  12  may be formed from a metal such as aluminum. Portions of housing  12  in the vicinity of antenna window  58  may be used as antenna ground. Antenna window  58  may be formed from a dielectric material such as polycarbonate (PC), acrylonitrile butadiene styrene (ABS), a PC/ABS blend, or other plastics (as examples). Window  58  may be attached to housing  12  using adhesive, fasteners, or other suitable attachment mechanisms. To ensure that device  10  has an attractive appearance, it may be desirable to form window  58  so that the exterior surfaces of window  58  conform to the edge profile exhibited by housing  12  in other portions of device  10 . For example, if housing  12  has straight edges  12 A and a flat bottom surface, window  58  may be formed with a right-angle bend and vertical sidewalls. If housing  12  has curved edges  12 A, window  58  may have a similarly curved exterior surface along the edge of device  10 . 
       FIG. 2  is a rear perspective view of device  10  of  FIG. 1  showing how device  10  may have a relatively planar rear surface  12 B and showing how antenna window  58  may be rectangular in shape with curved portions that match the shape of curved housing edges  12 A. Antenna window  58  may also have planar walls, if desired. 
     A schematic diagram of an illustrative configuration that may be used for electronic device  10  is shown in  FIG. 3 . As shown in  FIG. 3 , electronic device  10  may include control circuitry  29 . Control circuitry  29  may include storage and processing circuitry for controlling the operation of device  10 . Control circuitry  29  may, for example, 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. Control circuitry  29  may include processing circuitry based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors, power management units, audio codec chips, application specific integrated circuits, etc. 
     Control circuitry  29  may be used to run software on device  10 , such as operating system software and application software. Using this software, control circuitry  29  may, for example, transmit and receive wireless data, tune antennas to cover communications bands of interest, and perform other functions related to the operation of device  10 . 
     Input-output devices  30  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 circuitry  30  may include communications circuitry such as wired communications circuitry. Device  10  may also use wireless circuitry such as transceiver circuitry  206  and antenna structures  204  to communicate over one or more wireless communications bands. 
     Input-output devices  30  may also include input-output components with which a user can control the operation of device  10 . A user may, for example, supply commands through input-output devices  30  and may receive status information and other output from device  10  using the output resources of input-output devices  30 . 
     Input-output devices  30  may include sensors and status indicators such as an ambient light sensor, a proximity sensor, a temperature sensor, a pressure sensor, a magnetic sensor, an accelerometer, and light-emitting diodes and other components for gathering information about the environment in which device  10  is operating and providing information to a user of device  10  about the status of device  10 . Audio components in devices  30  may include speakers and tone generators for presenting sound to a user of device  10  and microphones for gathering user audio input. Devices  30  may include one or more displays. Displays may be used to present images for a user such as text, video, and still images. Sensors in devices  30  may include a touch sensor array that is formed as one of the layers in display  14 . During operation, user input may be gathered using buttons and other input-output components in devices  30  such as touch pad sensors, buttons, joysticks, click wheels, scrolling wheels, touch sensors such as a touch sensor array in a touch screen display or a touch pad, key pads, keyboards, vibrators, cameras, and other input-output components. 
     Wireless communications circuitry  34  may include radio-frequency (RF) transceiver circuitry such as transceiver circuitry  206  that is formed from one or more integrated circuits, power amplifier circuitry, low-noise input amplifiers, passive RF components, one or more antennas such as antenna structures  204 , 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 circuits for handling multiple radio-frequency communications bands. For example, circuitry  34  may include transceiver circuitry  206  for handling cellular telephone communications, wireless local area network signals, and satellite navigation system signals such as signals at 1575 MHz from satellites associated with the Global Positioning System. Transceiver circuitry  206  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  206  may use cellular telephone transceiver circuitry  38  for handling wireless communications in cellular telephone bands such as the bands in the range of 700 MHz to 2.7 GHz (as examples). 
     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 wireless circuitry for receiving radio and television signals, paging circuits, etc. In WiFi® and Bluetooth° links and other short-range wireless links, wireless signals are typically used to convey data over tens or hundreds of feet. In cellular telephone links and other long-range links, wireless signals are typically used to convey data over thousands of feet or miles. 
     Wireless communications circuitry  34  may include antenna structures  204 . Antenna structures  204  may include one or more antennas. Antenna structures  204  may include inverted-F antennas, patch antennas, loop antennas, monopoles, dipoles, single-band antennas, dual-band antennas, antennas that cover more than two bands, or other suitable antennas. Configurations in which at least one antenna in device  10  is formed from an inverted-F antenna structure such as a dual band inverted-F antenna are sometimes described herein as an example. 
     To provide antenna structures  204  with the ability to cover communications frequencies of interest, antenna structures  204  may be provided with tunable circuitry  208 . Tunable circuitry  208  may be controlled by control signals from control circuitry  29 . For example, control circuitry  29  may supply control signals to tunable circuitry  208  via control path  210  during operation of device  10  whenever it is desired to tune antenna structures  204  to cover a desired communications band. Path  222  may be used to convey data between control circuitry  29  and wireless communications circuitry  34  (e.g., when transmitting wireless data or when receiving and processing wireless data). 
     Transceiver circuitry  206  may be coupled to antenna structures  204  by signal paths such as signal path  212 . Signal path  212  may include one or more transmission lines. As an example, signal path  212  of  FIG. 3  may be a transmission line having a positive signal conductor such as line  214  and a ground signal conductor such as line  216 . Lines  214  and  216  may form parts of a coaxial cable or a microstrip transmission line having an impedance of 50 ohms (as an example). A matching network formed from components such as inductors, resistors, and capacitors may be used in matching the impedance of antenna structures  204  to the impedance of transmission line  212 . 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. 
     Transmission line  212  may be coupled to antenna feed structures associated with antenna structures  204 . As an example, antenna structures  204  may form an inverted-F antenna having an antenna feed with a positive antenna feed terminal such as terminal  218  and a ground antenna feed terminal such as ground antenna feed terminal  220 . Positive transmission line conductor  214  may be coupled to positive antenna feed terminal  218  and ground transmission line conductor  216  may be coupled to ground antenna feed terminal  220 . Other types of antenna feed arrangements may be used if desired. The illustrative feeding configuration of  FIG. 3  is merely illustrative. 
     Tunable circuitry  208  may be formed from one or more tunable circuits such as circuits based on capacitors, resistors, inductors, and switches. Tunable circuitry  208  may be implemented using discrete components mounted to a printed circuit such as a rigid printed circuit board (e.g., a printed circuit board formed from glass-filled epoxy), a flexible printed circuit formed from a sheet of polyimide or a layer of other flexible polymer, a plastic carrier, a glass carrier, a ceramic carrier, or other dielectric substrate. As an example, tunable circuitry  208  may be coupled to a dielectric carrier of the type that may be used in supporting antenna resonating element traces for antenna structures  204  ( FIG. 3 ). 
       FIGS. 4 ,  5 ,  6 ,  7 ,  8 ,  9 , and  10  are diagrams of illustrative tunable circuits of the types that may be used in implementing some or all of tunable antenna circuitry  208  of  FIG. 3 . Tunable antenna circuits  208  may have two or more terminals. For example, tunable antenna components  208  may each have respective first and second terminals  228  and  230 . Terminals  228  and  230  may be coupled to conductive structures at different respective locations within antenna structures  204 . During operation of device  10 , control circuitry  29  may issue commands on path  210  to adjust switches, variable components, and other adjustable circuitry in tunable circuitry  208 , thereby tuning antenna structures  204 . 
     As shown  FIG. 4 , tunable circuitry  208  may include a series-coupled inductor and switch such as inductor  224  and switch  226 . Inductor  224  and switch  226  may be connected in series between terminals  228  and  230 . Switch  226  may be closed to switch inductor  224  into use and may be opened when it is desired to remove inductor  224  from use in antenna structures  204 . 
     As shown in  FIG. 5 , tunable circuitry  208  may include a series-coupled capacitor and switch such as capacitor  232  and switch  234 . Capacitor  232  and switch  234  may be connected in series between terminals  228  and  230 . Switch  234  may be closed to switch capacitor  232  into use and may be opened when it is desired to remove capacitor  232  from use in antenna structures  204 . 
     Tunable components  208  may, if desired, use bypassable components. As shown in  FIG. 6 , for example, tunable circuit  208  may include an inductor such as inductor  236  that is coupled in parallel with a switch such as switch  238  between terminals  228  and  230 . Switch  238  may be closed when it is desired to bypass inductor  236 . As shown in  FIG. 7 , tunable circuit  208  may include a capacitor such as capacitor  240  that is coupled in parallel with a switch such as switch  242  between terminals  228  and  230 . Switch  242  may be closed when it is desired to bypass capacitor  240 . 
     Variable components such as varactors, variable inductors, and variable resistors may be used in tunable circuitry  208  to provide continuously adjustable component values.  FIG. 8  is a diagram of tunable circuitry  208  in a configuration based on varactors  244 .  FIG. 9  shows how variable inductor  246  may be used to form tunable circuitry  208 . Variable components may, if desired, be coupled in series or parallel with switches. 
     Switches in tunable circuitry  208  may be based on diodes, transistors, microelectromechanical systems (MEMS) devices, or other switching circuitry. 
     As shown in  FIG. 10 , tunable circuitry  208  may include multiple components  248 . Components  248  may be coupled in series and/or in parallel between terminals  228  and  230 . Each component  248  in  FIG. 10  may be implemented using one or more of the circuits of  FIGS. 4 ,  5 ,  6 ,  7 ,  8 , and  9 , switches, variable components, bypassable components, or other tunable components. As an example, tunable component  208  may be implemented using two or more or three or more series-connected adjustable inductors (e.g., inductors implemented using circuit  208  of  FIG. 4 , circuit  208  of  FIG. 6 , or circuit  208  of  FIG. 9 ). 
     As shown in  FIG. 11 , antenna structures  204  may be configured to exhibit multiple resonance peaks. In the graph of  FIG. 11 , antenna performance (standing-wave ratio) has been plotted as a function of antenna operating frequency f. In the  FIG. 11  example, antenna structures  204  have been configured for dual band operation, so antenna performance curve  249  exhibits two resonance peaks—a first resonance peak at lower frequencies (i.e., low band frequency band LB) and a second resonance peak at higher frequencies (i.e., high band frequency band HB). Low band frequencies LB and high band frequencies HB may, as an example, be associated with low band cellular telephone frequencies and high band cellular telephone frequencies and/or frequencies associated with satellite navigation system signals. If desired, low band frequencies LB and high band frequencies HB may be associated with other types of communications (e.g., wireless local area network communications, etc.). 
     With one suitable arrangement, low band LB may be associated with cellular telephone frequencies such as frequencies between 700 MHz and 960 MHz. High band HB may cover satellite navigation system frequency fg (e.g., a 1575 MHz frequency associated with use of Global Positioning System signals for satellite navigation) and cellular telephone signals up to about 2170 MHz (as an example). 
     During tuning operations, control circuitry  29  of  FIG. 3  may issue commands on control path  210  that adjust tunable circuitry  208 . The impact of adjusting tunable circuitry  208  on antenna performance depends on the configuration of tunable circuitry  208  and the conductive antenna structures in antenna structures  204 . With one suitable arrangement, tuning adjustments tend to alter low band performance more than high band performance. For example, low band tuning adjustments may leave high band HB unchanged, so that signals such as satellite navigation system signals at frequency fg can be received in high band HB regardless of whether or not tuning adjustments to low band LB are being made. 
     In the configuration of  FIG. 11 , dashed line  250  corresponds to the performance of antenna structures  204  following antenna tuning operations. As shown in the example of  FIG. 11 , the impact of the tuning components may be negligible in the high band (i.e., the upper frequency resonance peak at frequencies associated with high band HB may not change during tuning) and significant in the low band (i.e., the lower frequency resonance peak at frequencies associated with low band LB may shift). The lower frequency resonance peak of  FIG. 11  may, for example, move from position  252  (e.g., a frequency band covering 820 to 960 MHz or other suitable frequency band) to position  254  (e.g., a frequency band covering 700 to 780 MHz) as tunable circuitry  208  is adjusted. If desired, antenna structures  204  may exhibit different numbers of resonant peaks (one or more, two or more, three or more, or four or more) and different peaks may be adjustable through adjustment of tuning circuitry  208  (e.g., one of the peaks, two of the peaks, three of the peaks, or four or more of the peaks may be tuned). 
     A cross-sectional view of device  10  taken along line  1300  of  FIG. 2  and viewed in direction  1302  is shown in  FIG. 12 . As shown in  FIG. 12 , antenna structures  204  may be mounted within device  10  in the vicinity of antenna window  58 . Structures  204  may include conductive material that serves as an antenna resonating element for an antenna. The antenna may be fed using transmission line  212 . 
     Transmission line  212  may have a positive signal conductor that is coupled to a positive antenna feed terminal such as positive antenna feed terminal  218  of  FIG. 3  and a ground signal conductor that is coupled to a ground antenna feed terminal such as ground antenna feed terminal  220  of  FIG. 3  (i.e., antenna ground formed from conductive ground traces on a dielectric carrier in antenna structures  204  and/or grounded structures such as grounded portions of housing  12 ). 
     The antenna resonating element formed from structures  204  may be based on any suitable antenna resonating element design (e.g., structures  204  may form a patch antenna resonating element, a single arm inverted-F antenna structure, a dual-arm inverted-F antenna structure, other suitable multi-arm or single arm inverted-F antenna structures, a closed and/or open slot antenna structure, a loop antenna structure, a monopole, a dipole, a planar inverted-F antenna structure, a hybrid of any two or more of these designs, etc.). Housing  12  may serve as antenna ground for an antenna formed from structure  204  and/or other conductive structures within device  10  and antenna structures  204  may serve as ground (e.g., conductive components, traces on printed circuits, etc.). 
     Structures  204  may include patterned conductive structures such as patterned metal structures. The patterned conductive structures may, if desired, be supported by a dielectric carrier. The conductive structures may be formed from a coating, from metal traces on a flexible printed circuit, or from metal traces formed on a plastic carrier using laser-processing techniques or other patterning techniques. Structures  204  may also be formed from stamped metal foil or other metal structures. In configurations for antenna structures  204  that include a dielectric carrier, metal layers may be formed directly on the surface of the dielectric carrier and/or a flexible printed circuit that includes patterned metal traces may be attached to the surface of the dielectric carrier. If desired, conductive material in structures  204  may also form one or more proximity sensor capacitor electrodes. 
     During operation of the antenna formed from structures  204 , radio-frequency antenna signals can be conveyed through dielectric window  58 . Radio-frequency antenna signals associated with structures  204  may also be conveyed through a display cover member such as cover layer  60 . Display cover layer  60  may be formed from one or more clear layers of glass, plastic, or other materials. Display  50  may have an active region such as region  56  in which cover layer  60  has underlying conductive structure such as display panel module  64 . The structures in display panel  64  such as touch sensor electrodes and active display pixel circuitry may be conductive and may therefore attenuate radio-frequency signals. In region  54 , however, display  50  may be inactive (i.e., panel  64  may be absent). An opaque masking layer such as plastic or ink  62  may be formed on the underside of transparent cover glass  60  in region  54  to block antenna structures  204  from view by a user of device  10 . Opaque material  62  and the dielectric material of cover layer  60  in region  54  may be sufficiently transparent to radio-frequency signals that radio-frequency signals can be conveyed through these structures during operation of device  10 . 
     Device  10  may include one or more internal electrical components such as components  23 . Components  23  may include storage and processing circuitry such as microprocessors, digital signal processors, application specific integrated circuits, memory chips, and other control circuitry such as control circuitry  29  of  FIG. 3 . Components  23  may be mounted on one or more substrates such as substrate  79  (e.g., rigid printed circuit boards such as boards formed from fiberglass-filled epoxy, flexible printed circuits, molded plastic substrates, etc.). Components  23  may include input-output circuitry such as sensor circuitry (e.g., capacitive proximity sensor circuitry), wireless circuitry such as radio-frequency transceiver circuitry  206  of  FIG. 3  (e.g., circuitry for cellular telephone communications, wireless local area network communications, satellite navigation system communications, near field communications, and other wireless communications), amplifier circuitry, and other circuits. Connectors such as connector  81  may be used in interconnecting circuitry  23  to communications paths such as transmission line path  212 . 
       FIG. 13  is a diagram of an illustrative dual-band antenna of the type that may be formed using antenna structures  204 . As shown in  FIG. 13 , antenna structures  204  may include antenna resonating element  256  and antenna ground  258 . Antenna ground  258  may be formed from conductive portions of antenna structures  204  on a dielectric carrier and/or ground structures such as portions of metal housing  12  that serve as antenna ground. Antenna resonating element  256  may have a resonating element arm structure having a low band arm  264  for resonating in low band LB and high band arm  266  for resonating in high band HB. Short circuit path  262  may couple resonating element arms  264  and  266  to ground  258 . Antenna feed  260 , which may be formed in parallel with short circuit branch  262 , may have a positive antenna feed terminal such as positive antenna feed terminal  218  and a ground antenna feed terminal such as ground antenna feed terminal  220 . 
     During operation, low band arm  264  may give rise to an antenna resonance such as resonance LB in  FIG. 11  and high band arm  266  may give rise to an antenna resonance such as resonance HB in  FIG. 11 . Optional tunable circuitry  208  may be used to tune antenna structures  204  (e.g., to move LB peak  252  to peak position  254 . Tunable circuitry  208  may be coupled between any two conductive points on antenna structures  204 . The locations of terminals  228  and  230  in  FIG. 13  are merely illustrative. 
       FIG. 14  shows how conductive structures for antenna structures  204  may be supported by a dielectric carrier. As shown in  FIG. 14 , antenna structures  204  may have conductive structures  270  such as metal structures that are supported by dielectric carrier  268 . Conductive structures  270  may be metal traces that are formed on the surface of dielectric carrier  268 , may be metal traces on a flexible printed circuit that is mounted on dielectric carrier  268 , may be other metal structures supported by carrier  268  (e.g., patterned metal foil), or may be other conductive structures. 
     Dielectric carrier  268  may be formed from a dielectric material such as glass, ceramic, or plastic. As an example, dielectric carrier  268  may be formed from plastic parts that are molded and/or machined into a desired shape such as the illustrative rectangular prism shape (rectangular box shape) of  FIG. 14 . If desired, other dielectric carrier shapes (e.g., box or prism shapes with different numbers of sides or other three-dimensional carrier shapes) may be used for antenna structures  204 . The example of  FIG. 14  is merely illustrative. 
     As shown in the  FIG. 14  configuration, dielectric carrier  268  may have six sides: side I, side II, side III, side IV, side V, and side VI. Metal traces  270  may cover at least some of each of the six sides of carrier  268 . Forming antenna structures  204  in this way allows antenna structures  204  to efficiently use a limited volume within device  10  to form an antenna with resonances at desired frequencies. Openings in metal traces  270  (e.g., slot-shaped openings, etc.) may be used to help control the flow of currents in metal traces  270  and thereby adjust antenna performance. If desired, carrier  268  may have other numbers of sides (e.g., four sides, five sides, more than two sides, less than six sides, four or more sides, five or more sides, etc.). The use of six planar sides for carrier  268  is merely illustrative. 
       FIG. 15  is a diagram showing an illustrative pattern that may be used for metal structures  270 . In the arrangement of  FIG. 15 , structures  270  have been unwrapped from carrier  268  and laid out flat. Dashed lines  274  represent fold lines (i.e., axes along which structures  270  are folded when wrapped around carrier  268  to form antenna structures  204  of  FIG. 14 ). Openings such as openings  272  are used to form a desired pattern for conductive structures  270 . Metal strip portion  262  of metal structures  270  may serve as short circuit path  262  of  FIG. 13 . Dotted line path  266  in metal structures  270  shows how portions of metal structures  270  may serve as high band resonating element arm  266  of  FIG. 13 . Dashed-and-dotted lines  264  in metal structures  270  show how portions of metal structures  270  may also serve as low band resonating element arm  264  of  FIG. 13 . Transmission line  212  ( FIG. 3 ) may be coupled to antenna feed terminals  218  and  220 . Other patterns may be used for metal structures  270  if desired. The configuration of  FIG. 15  in which metal structures  270  form a three-dimensional wrapped metal sheet surrounding carrier  268  to implement a dual-band (dual-arm) inverted-F antenna of the type shown in  FIG. 13  is merely illustrative. 
     To provide antenna structures  204  with the ability to be tuned to cover different desired communications bands during use, antenna structures  204  may be provided with tunable circuitry  208 . As an example, terminal  228  of tunable circuitry  208  may be coupled to a first location on conductive structures  270  such as one of locations  265  of  FIG. 15  and terminal  230  of tunable circuitry  208  may be coupled to a second location on conductive structures  270  such as another one of locations  265  of  FIG. 15 . In general, locations  265  may be positioned at any points on metal structures  270  that provide a desired amount of antenna response tuning. Locations  265  of  FIG. 15  are merely illustrative. 
     As shown in  FIG. 16 , dielectric carrier  268  may be formed from a structure that contains one or more cavities (i.e., dielectric carrier  268  may be hollow). In the illustrative configuration shown in  FIG. 16 , dielectric carrier  268  has three cavities  276 . Cavities  276  may, for example, be filled with air, porous material with a low dielectric constant, foam, or other materials. Dielectric carrier  268  may have a body such as portion  278  and a lid portion such as lid  280 . Structures  280  and  278  may be attached by adhesive, welds, screws, solder, or other fasteners and attachment mechanisms. As an example, lid  280  may be attached to body  278  using adhesive to seal cavities  276 . 
     Conductive structures  270  may be formed from patterned metal traces formed directly on the surface of dielectric carrier  268 , as shown in the cross-sectional side view of  FIG. 17 . The pattern of metal used in forming structures  270  may be created by photolithographic patterning, using laser direct structuring (LDS) techniques in which applied laser light (or other activation mechanism) is used to selectively activate desired surface regions on a plastic carrier that are subsequently electroplated or otherwise coated with metal to form patterned metal structures  270 , or molded interconnect device (MID) techniques in which multiple shots of plastic (some metal-attracting and some metal-repelling) are used to create desired metal patterns  270  following electroplating or other metal coating operations. 
       FIG. 18  shows how a flexible printed circuit such as flexible printed circuit  282  may be provided with metal traces such as metal traces  270 B. Adhesive  286 , solder, welds, screws, or other fastening arrangements may be used to attach flexible printed circuit  282  to dielectric carrier  268 . Metal traces  270 A may be formed on the surface of dielectric carrier  268 . Metal traces  270 A and  270 B may form metal structures  270  for antenna structures  204 . 
       FIG. 19  shows how a flexible printed circuit such as flexible printed circuit  284  may be wrapped around carrier  268  (e.g., on six sides of carrier  268 ). Traces  270  on flexible printed circuit  284  may be used to form the conductive structures of antenna structures  204 . 
     In the illustrative configuration of  FIG. 20 , antenna structures  204  have been formed from metal foil  270  that has been stamped or otherwise formed into a shape that is wrapped around dielectric carrier  268  (e.g., on six sides of carrier  268 ). Adhesive, screws, or other attachment mechanisms may be used in attaching foil  270  to carrier  268 . 
       FIG. 21  is a perspective view of antenna structures  204  in a configuration in which conductive structures  270  on dielectric carrier  268  have been provided with tunable circuitry  208 . Tunable circuitry  208  may be implemented using one or more components such as components  302 . Components  302  may be surface mount technology (SMT) components or other circuits for implementing circuitry of the type described in connection with  FIGS. 4 ,  5 ,  6 ,  7 ,  8 ,  9 , and  10 . Components  302  may be mounted on a substrate such as flexible printed circuit substrate  300  (e.g., using solder). Substrate  300  may have traces that couple the circuitry of components  302  to locations on structures  270  such as locations  265  of  FIG. 15 , thereby coupling tunable circuitry  208  into the conductive structures of antenna structures  204 . Tunable circuitry  208  may be used to adjust the performance of antenna structures  204  as described in connection with  FIG. 11  during operation of electronic device  10 . 
       FIG. 22  is a cross-sectional side view of a portion of antenna structures  204  in a configuration in which layers of plastic (e.g., multiple shots of injection molded plastic) have been used in forming layers of structures  204 . First plastic shot  304  may form the main body of dielectric carrier  268 . Metal structures  270 - 1  may be patterned metal traces that are deposited directly on the surface of plastic structure  304 . Second plastic shot  308  may be formed on top of metal layer  270 - 1 . Vias may be formed and filled with metal  270 - 3 . Metal traces  270 - 2  may then be deposited and patterned on top of second plastic structures  308 . Components such as component  306  or other structures may be coupled to metal traces  270 - 2  (e.g., to implement tunable circuitry  208 ). Structures  270 - 1 ,  270 - 2 , and  270 - 3  of  FIG. 22  may serve as conductive structures  270  of antenna structures  204  (see, e.g.,  FIG. 15 ). 
     The foregoing is merely illustrative of the principles of this invention and various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention.

Metadata:
Filing Date: 20121008
Publication Date: 20150929
Grant Date: 20150929
Priority Date: 20121008
Inventors: YARGA SALIH
LI QINGXIANG
MOW MATTHEW A.
SCHLUB ROBERT W.
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q1/38", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q9/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/38", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q9/06", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 50433097