PATENT DOCUMENT

Publication Number: US-9160056-B2
Application Number: US-75296610-A
Country: US
Kind Code: B2

Title: Multiband antennas formed from bezel bands with gaps

Abstract:
Electronic devices are provided that contain wireless communications circuitry. The wireless communications circuitry may include radio-frequency transceiver circuitry and antenna structures. An inverted-F antenna may have first and second short circuit legs and a feed leg. The first and second short circuit legs and the feed leg may be connected to a folded antenna resonating element arm. The antenna resonating element arm and the first short circuit leg may be formed from portions of a conductive electronic device bezel. The folded antenna resonating element arm may have a bend. The bezel may have a gap that is located at the bend. Part of the folded resonating element arm may be formed from a conductive trace on a dielectric member. A spring may be used in connecting the conductive trace to the electronic device bezel portion of the antenna resonating element arm.

Claims:
What is claimed is: 
     
       1. An inverted-F antenna in an electronic device having a periphery and an exterior surface, a length, a width that is less than the length, and a height that is less than the width, comprising:
 a resonating element arm formed at least partly from conductive structures on the periphery at the exterior surface of the electronic device, wherein the conductive structures comprise a conductive bezel that surrounds the periphery of the electronic device; 
 a feed leg that contacts the resonating element arm; 
 a ground; 
 a short circuit leg that connects an end of the resonating element arm to the ground; 
 a first antenna feed terminal that is connected to the feed leg; 
 a second antenna feed terminal that is coupled to the ground; and 
 an additional short circuit leg connected between the resonating element arm and the ground in parallel with the short circuit leg, wherein the short circuit leg is formed at least partly from a first segment of the conductive bezel that extends across the height of the electronic device, the resonating element arm is formed at least partly from a second segment of the conductive bezel that extends across the height of the electronic device, and the first and second segments extend respectively along first and second perpendicular exterior surfaces of the electronic device. 
 
     
     
       2. The antenna defined in  claim 1  wherein the conductive bezel is interrupted by at least one gap. 
     
     
       3. The inverted-F antenna defined in  claim 2 , wherein the second segment of the conductive bezel has a first end and an opposing second end, the first segment of the conductive bezel that forms the short circuit leg is directly connected to the first end, the gap is formed at the second end, and the additional short circuit leg is connected to the second segment of the conductive bezel between the first and second ends of the second segment. 
     
     
       4. The inverted-F antenna defined in  claim 3 , wherein the ground comprises a ground plane that substantially extends across the width of the electronic device, wherein the first segment of the conductive bezel, the second segment of the conductive bezel, and the ground plane define a dielectric-filled opening, and the additional short circuit leg bridges the dielectric-filled opening to connect the second segment of the conductive bezel to the ground plane. 
     
     
       5. The antenna defined in  claim 2  further comprising a dielectric member and a conductive trace on the dielectric member, wherein the resonating element arm is formed partly from the second segment of the conductive bezel and partly from the conductive trace on the dielectric member. 
     
     
       6. The antenna defined in  claim 5  further comprising a spring that forms part of the resonating element arm. 
     
     
       7. The antenna defined in  claim 6  wherein the spring has a first end connected to the second segment of the conductive bezel and a second end connected to the conductive trace on the dielectric member. 
     
     
       8. The antenna defined in  claim 7  wherein the spring is welded to the second segment of the conductive bezel. 
     
     
       9. The antenna defined in  claim 1  further comprising a dielectric member and a conductive trace on the dielectric member, wherein the resonating element arm is formed partly from the second segment of the conductive bezel and partly from the conductive trace on the dielectric member. 
     
     
       10. The antenna defined in  claim 9  further comprising a spring connected between the second segment of the conductive bezel and the conductive trace. 
     
     
       11. An inverted-F antenna in an electronic device that has peripheral edges, an interior, and an exterior, comprising:
 a resonating element arm formed at least partly from a segment of conductive housing structure that lies along one of the edges, wherein the segment of conductive housing structure is separated from an additional segment of the conductive housing structure by a dielectric-filled gap and the segment conductive housing structure includes a portion that extends towards the interior of the electronic device adjacent to the dielectric-filled gap; 
 a ground; 
 a short circuit leg that connects the resonating element arm to the ground; 
 a dielectric member; and 
 a conductive trace on the dielectric member, wherein the conductive trace is connected to the portion of the segment of conductive housing structure, and the resonating element arm comprises a first portion that is formed from the segment of conductive housing structure and a second portion that is formed from the conductive trace. 
 
     
     
       12. The inverted-F antenna defined in  claim 11  wherein the segment of conductive housing structure comprises part of a conductive bezel that surrounds substantially all of the peripheral edges of the electronic device, the inverted-F antenna further comprising a feed leg that is connected to the resonating element arm. 
     
     
       13. The inverted-F antenna defined in  claim 12  wherein the short circuit leg is formed from part of the conductive bezel. 
     
     
       14. The inverted-F antenna defined in  claim 13  further comprising an additional short circuit leg that connects the resonating element arm to the ground. 
     
     
       15. The inverted-F antenna defined in  claim 14  wherein the resonating element arm comprises at least one 180° bend. 
     
     
       16. The inverted-F antenna defined in  claim 11  wherein the conductive housing structure comprises part of a conductive bezel that surrounds the peripheral edges of the electronic device, wherein the resonating element arm has a bend, and wherein the conductive bezel has a gap at the bend of the resonating element arm. 
     
     
       17. The inverted-F antenna defined in  claim 11 , further comprising:
 a feed leg that contacts the resonating element arm; 
 a first antenna feed terminal that is connected to the feed leg; and 
 a transmission line structure having a signal conductor coupled between radio-frequency transceiver circuitry and the first antenna feed terminal, wherein the short circuit leg is connected to a first end of the segment of the conductive housing structure that forms the first portion of the resonating element arm, the conductive trace that forms the second portion of the resonating element arm is connected to a second end of the segment of the conductive housing structure that forms the first portion of the resonating element arm, and the feed leg is connected to the segment of the conductive housing structure that forms the first portion of the resonating element arm at an intermediate location between the first and second ends of the segment of the conductive housing structure that forms the first portion of the resonating element arm. 
 
     
     
       18. A handheld electronic device having front and rear surfaces, four edges, a length, and a width, comprising:
 a conductive bezel having four side walls that each substantially extends along a respective edge of the handheld electronic device at an exterior of the handheld electronic device, wherein the four sidewalls have a height that is substantially less than the length and the width of the handheld electronic device, the conductive bezel has at least one gap, and the gap extends from the rear surface to the front surface of the handheld electronic device; 
 an inverted-F antenna having an antenna resonating element that is formed from a segment of the conductive bezel adjacent to the gap and having a short circuit leg that is separate from the conductive bezel; and 
 a ground plane for the inverted-F antenna that extends across the width of the handheld electronic device, wherein a dielectric-filled opening is formed between the ground plane and the conductive bezel, and the short circuit leg extends from the ground plane to the conductive bezel across the dielectric-filled opening. 
 
     
     
       19. The handheld electronic device defined in  claim 18  wherein the inverted-F antenna comprises:
 an additional short circuit leg that connects an end of the antenna resonating element to the ground, wherein the additional short circuit leg is formed from an additional segment of the conductive bezel. 
 
     
     
       20. The handheld electronic device defined in  claim 19  further comprising:
 a first antenna feed terminal connected to the ground; 
 a second antenna feed terminal; 
 a feed leg connected between the antenna resonating element and the second antenna feed terminal, wherein the antenna resonating element arm includes conductive structures that are separate from the conductive bezel.

Description:
BACKGROUND 
     This relates generally to wireless communications circuitry, and more particularly, to electronic devices that have wireless communications circuitry. 
     Electronic devices such as 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 use long-range wireless communications circuitry such as cellular telephone circuitry to communicate using cellular telephone bands. Electronic devices may use short-range wireless communications links to handle communications with nearby equipment. For example, electronic devices may communicate using the WiFi® (IEEE 802.11) bands at 2.4 GHz and 5 GHz and the Bluetooth® band at 2.4 GHz. Some devices incorporate wireless circuitry for receiving Global Positioning System (GPS) signals at 1575 MHz. 
     To satisfy consumer demand for small form factor wireless devices, manufacturers are continually striving to implement wireless communications circuitry such as antenna components using compact structures. At the same time, it may be desirable to include conductive structures in an electronic device such as metal device housing components. Because conductive components can affect radio-frequency performance, care must be taken when incorporating antennas into an electronic device that includes conductive structures. 
     It would therefore be desirable to be able to provide improved wireless communications circuitry for wireless electronic devices. 
     SUMMARY 
     Electronic devices may be provided that include antenna structures. An inverted-F antenna may be configured to operate in first and second communications bands. An electronic device may contain radio-frequency transceiver circuitry that is coupled to the antenna using a transmission line. The transmission line may have a positive conductor and a ground conductor. The antenna may have a positive antenna feed terminal and a ground antenna feed terminal to which the positive and ground conductors of the transmission line are respectively coupled. 
     The electronic device may have a rectangular periphery. A rectangular display may be mounted on a front face of the electronic device. Conductive sidewall structures may run around the periphery of the electronic device housing and display. The conductive sidewall structures may serve as a bezel for the display. 
     The bezel may include at least one gap. The gap may be filled with a solid dielectric such as plastic. The antenna may have a main resonating element arm. The resonating element arm may be folded at a bend. A first segment of the resonating element arm may be formed from a portion of the bezel. A second segment of the resonating element arm may be formed from a conductive trace on a dielectric member. A spring in the vicinity of the bend may be used in connecting the first and second segments of the resonating element arm. The bend may be located at the gap in the bezel. 
     First and second parallel short circuit legs may connect the antenna resonating element arm to a ground. A feed leg may be connected between the antenna resonating element and a first antenna feed terminal. A second antenna feed terminal may be connected to the ground. The first short circuit leg may be formed from a portion of the bezel. 
     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 perspective view of an illustrative electronic device with wireless communications circuitry in accordance with an embodiment of the present invention. 
         FIG. 2  is a schematic diagram of an illustrative electronic device with wireless communications circuitry in accordance with an embodiment of the present invention. 
         FIG. 3  is a cross-sectional view of an illustrative electronic device with wireless communications circuitry in accordance with an embodiment of the present invention. 
         FIG. 4  is a diagram of an illustrative inverted-F antenna in accordance with an embodiment of the present invention. 
         FIG. 5  is a schematic diagram of an illustrative folded inverted-F antenna in accordance with an embodiment of the present invention. 
         FIG. 6  is a top view of an electronic device showing how the electronic device may be provided with a folded inverted-F antenna having a shorting leg in accordance with an embodiment of the present invention. 
         FIG. 7  is a Smith chart illustrating the performance of an antenna of the type shown in  FIG. 6  in accordance with an embodiment of the present invention. 
         FIG. 8  is a graph showing the performance of an antenna of the type shown in  FIG. 6  in the absence of the shorting leg in accordance with an embodiment of the present invention. 
         FIG. 9  is a graph showing the performance of an antenna of the type shown in  FIG. 6  in the presence of the shorting leg in accordance with an embodiment of the present invention. 
         FIG. 10  is a top view of an illustrative electronic device that includes an antenna of the type shown in  FIG. 6  that has been formed using part of a conductive bezel that surrounds the periphery of the electronic device in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices 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 or more antennas. 
     The antennas can include inverted-F antennas. An inverted-F antenna for an electronic device may include a folded arm. The use of a folded arm may help minimize the size of the antenna. A shorting structure in the inverted-F antenna may enhance the performance of the antenna by allowing the antenna to operate efficiently in multiple communications bands. 
     Conductive structures for an inverted-F antenna 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 a conductive structure that surrounds the periphery of the device. This structure may take the form of a conductive metal band that surrounds all four edges of the device. A display and other components may be mounted to the device within the confines of the metal band. In this respect, the metal band may serve as a bezel and may therefore sometimes be referred to herein as a bezel or conductive bezel structure. 
     Gap structures may be formed in the bezel. The presence of a gap may, for example, help define the location of a fold in a folded inverted-F antenna resonating element arm. 
     Any suitable electronic devices may be provided with wireless circuitry that includes inverted-F antenna structures that are based on conductive device structures such as device bezels. As an example, inverted-F antenna structures of this type may be used in electronic devices such as desktop computers, game consoles, routers, laptop computers, etc. With one suitable configuration, bezel-based inverted-F antenna structures are provided in relatively compact electronic devices in which interior space is relatively valuable such as portable electronic devices. 
     An illustrative portable electronic device in accordance with an embodiment of the present invention is shown in  FIG. 1 . Portable electronic devices such as illustrative portable electronic device  10  of  FIG. 1  may be laptop computers or small portable computers such as ultraportable computers, netbook computers, and tablet computers. Portable electronic devices may also be somewhat smaller devices. Examples of smaller portable electronic devices include wrist-watch devices, pendant devices, headphone and earpiece devices, and other wearable and miniature devices. With one suitable arrangement, the portable electronic devices are handheld electronic devices such as cellular telephones. 
     Space is at a premium in portable electronic devices. Conductive structures are also typically present, which can make efficient antenna operation challenging. For example, conductive housing structures may be present around some or all of the periphery of a portable electronic device housing. 
     In portable electronic device housing arrangements such as these, it may be particularly advantageous to use an inverted-F antenna in which some of the antenna is formed using conductive housing structures. The use of portable devices such as handheld devices is therefore sometimes described herein as an example, although any suitable electronic device may be provided with inverted-F antenna structures, if desired. 
     Handheld devices may be, for example, cellular telephones, media players with wireless communications capabilities, handheld computers (also sometimes called personal digital assistants), remote controllers, global positioning system (GPS) devices, and handheld gaming devices. Handheld devices and other portable devices may, if desired, include the functionality of multiple conventional devices. Examples of multi-functional devices include cellular telephones that include media player functionality, gaming devices that include wireless communications capabilities, cellular telephones that include game and email functions, and handheld devices that receive email, support mobile telephone calls, and support web browsing. These are merely illustrative examples. Device  10  of  FIG. 1  may be any suitable portable or handheld electronic device. 
     Device  10  includes housing  12  and includes at least one antenna for handling wireless communications. Housing  12 , which is sometimes referred to as a case, may be formed of any suitable materials including, plastic, glass, ceramics, carbon-fiber composites and other composites, metal, 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, so that the operation of conductive antenna elements that are located within housing  12  is not disrupted. In other situations, housing  12  may be formed from metal elements. 
     Device  10  may, if desired, have a display such as display  14 . Display  14  may, for example, be a touch screen that incorporates capacitive touch electrodes. Display  14  may include image pixels formed form light-emitting diodes (LEDs), organic LEDs (OLEDs), plasma cells, electronic ink elements, liquid crystal display (LCD) components, or other suitable image pixel structures. A cover glass member may cover the surface of display  14 . Buttons such as button  19  may pass through openings in the cover glass. 
     Housing  12  may include sidewall structures such as housing sidewall structures  16 . Structures  16  may be implemented using conductive materials. For example, structures  16  may be implemented using a conductive ring-shaped member that substantially surrounds the rectangular periphery of display  14 . Structures of this type are sometimes said to form a band around the periphery of device  10 , so sidewall structures  16  may sometimes be referred to as band structures, a band member, or a band. 
     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 structures  16 . Structures  16  may serve as a bezel that holds display  14  to the front (top) face of device  10 . Structures  16  are therefore sometimes referred to herein as bezel structures  16  or bezel  16 . 
     Bezel  16  runs around the rectangular periphery of device  10  and display  14 . Bezel  16  may be confined to the upper portions of device  10  (i.e., peripheral regions that lie near the surface of display  14 ) or may cover the entire vertical height of the sidewalls of device  10  (e.g., as shown in the example of  FIG. 1 ). Other configurations are also possible such as configurations in which bezel  16  or other sidewall structures are partly or fully integrated with the rear wall of housing  12  (e.g., in a unibody-type construction). 
     Bezel (band)  16  may have a thickness (dimension TT) of about 0.1 mm to 3 mm (as an example). The sidewall portions of bezel  16  may be substantially vertical (parallel to vertical axis V) or may be curved. In the example of  FIG. 1 , bezel  16  has relatively planar exterior surfaces. Parallel to axis V, bezel  16  may have a dimension TZ of about 1 mm to 2 cm (as an example). The aspect ratio R of bezel  16  (i.e., the ratio R of TZ to TT) is typically more than 1 (i.e., R may be greater than or equal to 1, greater than or equal to 2, greater than or equal to 4, greater than or equal to 10, etc.). 
     It is not necessary for bezel  16  to have a uniform cross-section. For example, the top portion of bezel  16  may, if desired, have an inwardly protruding lip that helps hold display  14  in place. If desired, the bottom portion of bezel  16  may also have an enlarged lip (e.g., in the plane of the rear surface of device  10 ). In the example of  FIG. 1 , bezel  16  has substantially straight vertical sidewalls. This is merely illustrative. The interior and exterior surfaces of bezel  16  may be curved or may have any other suitable shapes. 
     Display  14  includes conductive structures. The conductive structures may include an array of capacitive electrodes, conductive lines for addressing pixel elements, driver circuits, etc. These conductive structures tend to block radio-frequency signals. It may therefore be desirable to form some or all of the rear planar surface of device from a dielectric material such as glass or plastic, so that antenna signals are not blocked. If desired, the rear of housing  12  may be formed from metal and other portions of device  10  may be formed from dielectric. For example, antenna structures may be located under dielectric portions of display  14  such as portions of display  14  that are covered with cover glass and that do not contain conductive components. 
     Portions of bezel  16  may be provided with gap structures. For example, bezel  16  may be provided with one or more gaps such as gap  18 , as shown in  FIG. 1 . Gap  18  lies along the periphery of the housing of device  10  and display  12  and is therefore sometimes referred to as a peripheral gap. Gap  18  divides bezel  16  (i.e., there is generally no conductive portion of bezel  16  in gap  18 ). Gap  18  therefore interrupts bezel  16  as bezel  16  runs around the periphery of device  10 . Because gap  18  is interposed within bezel  16  in this way, the electrical continuity of bezel  16  is broken (i.e., there is an open circuit in bezel  16  across gap  18 ). 
     As shown in  FIG. 1 , gap  18  may be filled with dielectric. For example, gap  18  may be filled with air. To help provide device  10  with a smooth uninterrupted appearance and to ensure that bezel  16  is aesthetically appealing, gap  18  may be filled with a solid (non-air) dielectric such as plastic. Bezel  16  and gaps such as gap (and its associated plastic filler structure) may form part of one or more antennas in device  10 . For example, portions of bezel  16  and gaps such as gap  18  may, in conjunction with internal conductive structures, form one or more inverted-F antennas. The internal conductive structures may include printed circuit board structures, frame members or other support structures, conductive traces formed on the surface of plastic supports, fasteners such as screws, springs, strips of metal, wires, and other suitable conductive structures. 
     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 upper antenna may, for example, be formed partly from the portions of bezel  16  in the vicinity of gap  18 . The lower antenna may likewise be formed from portions of bezel  16  and a corresponding bezel gap. 
     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, Bluetooth® communications, etc. As an example, the lower antenna in region  20  of device  10  may be used in handling voice and data communications in one or more cellular telephone bands, whereas the upper antenna in region  22  of device  10  may provide coverage in a first band for handling Global Positioning System (GPS) signals at 1575 MHz and a second band for handling Bluetooth® and IEEE 802.11 (wireless local area network) signals at 2.4 GHz (as examples). The lower antenna (in this example) may be implemented using a loop antenna design and the upper antenna may be implemented using an inverted-F antenna design. 
     A schematic diagram of an illustrative electronic device is shown in  FIG. 2 . Device  10  of  FIG. 2  may be a portable computer such as a portable tablet computer, a mobile telephone, a mobile telephone with media player capabilities, a handheld computer, a remote control, a game player, a global positioning system (GPS) device, a combination of such devices, or any other suitable electronic device. 
     As shown in  FIG. 2 , device  10  may include 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, applications specific integrated circuits, etc. 
     Storage and processing circuitry  28  may be used to run software on device  10 , such as internet browsing applications, voice-over-internet-protocol (VoIP) telephone call applications, email applications, media playback applications, operating system functions, etc. To support interactions with external equipment, storage and processing circuitry  28  may be used in implementing communications protocols. Communications protocols that may be implemented using storage and processing circuitry  28  include internet protocols, wireless local area network protocols (e.g., IEEE 802.11 protocols—sometimes referred to as WiFi®), protocols for other short-range wireless communications links such as the Bluetooth® protocol, cellular telephone protocols, etc. 
     Input-output circuitry  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 devices  32  such as touch screens and other user input interface are examples of input-output circuitry  32 . Input-output devices  32  may also include user input-output devices such as buttons, joysticks, click wheels, scrolling wheels, touch pads, key pads, keyboards, microphones, cameras, etc. A user can control the operation of device  10  by supplying commands through such user input devices. Display and audio devices such as display  14  ( FIG. 1 ) and other components that present visual information and status data may be included in devices  32 . Display and audio components in input-output devices  32  may also include audio equipment such as speakers and other devices for creating sound. If desired, input-output devices  32  may contain audio-video interface equipment such as jacks and other connectors for external headphones and monitors. 
     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, 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  36  and  38 . 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 cellular telephone bands such as the GSM bands at 850 MHz, 900 MHz, 1800 MHz, and 1900 MHz, and the 2100 MHz data band (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 global positioning system (GPS) receiver equipment such as GPS receiver circuitry  37  for receiving GPS signals at 1575 MHz or for handling other satellite positioning data, 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 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 structure, 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. 
     With one suitable arrangement, which is sometimes described herein as an example, the upper antenna in device (i.e., an antenna  40  located in region  22  of device  10  of  FIG. 1 ) may be formed using an inverted-F antenna design in which some of the antenna includes conductive device structures such as portions of bezel  16 . Gap  18  may help define the shape and size of the portion of bezel  16  that operates as part of the antenna. 
     A cross-sectional side view of an illustrative device  10  is shown in  FIG. 3 . As shown in  FIG. 3 , display  14  may be mounted to the front surface of device  10  using bezel  16 . Housing  12  may include sidewalls formed from bezel  16  and one or more rear walls formed from structures such as planar rear housing structure  42 . Structure  42  may be formed from a dielectric such as glass, ceramic, composites, plastic or other suitable materials. Snaps, clips, screws, adhesive, and other structures may be used in mounting display  14 , bezel  16 , and rear housing wall structure  42  within device  10 . 
     Device  10  may contain printed circuit boards such as printed circuit board  46 . Printed circuit board  46  and the other printed circuit boards in device  10  may be formed from rigid printed circuit board material (e.g., fiberglass-filled epoxy) or flexible sheets of material such as polymers. Flexible printed circuit boards (“flex circuits”) may, for example, be formed from flexible sheets of polyimide. 
     Printed circuit board  46  may contain interconnects such as interconnects  48 . Interconnects  48  may be formed from conductive traces (e.g., traces of gold-plated copper or other metals). Connectors such as connector  50  may be connected to interconnects  48  using solder or conductive adhesive (as examples). Integrated circuits, discrete components such as resistors, capacitors, and inductors, and other electronic components may be mounted to printed circuit board  46 . 
     Antenna  40  may have antenna feed terminals. For example, antenna  40  may have a positive antenna feed terminal such as positive antenna feed terminal  58  and a ground antenna feed terminal such as ground antenna feed terminal  54 . In the illustrative arrangement of  FIG. 3 , a transmission line path such as coaxial cable  52  may be coupled between the antenna feed formed from terminals  58  and  54  and transceiver circuitry in components  44  via connector  50  and interconnects  48 . This is merely illustrative. Radio-frequency antenna signals may be conveyed between antenna  40  and transceiver circuits on device  10  using any suitable arrangement (e.g., transmission lines formed from traces on a printed circuit board, etc.). 
     Components  44  may include one or more integrated circuits for implementing transceiver (receiver) circuitry  37  and transceiver circuits  36  and  38  of  FIG. 2 . Connector  50  may be, for example, a coaxial cable connector that is connected to printed circuit board  46 . Cable  52  may be a coaxial cable or other transmission line. Terminal  58  may be coupled to a positive conductor in transmission line  52  (e.g., a coaxial cable center connector  56 ). Terminal  54  may be connected to a ground conductor in transmission line  52  (e.g., a conductive outer braid conductor in a coaxial cable). Other arrangements may be used for coupling transceivers in device  10  to antenna  40  if desired (e.g., using transmission lines formed on printed circuits). The arrangement of  FIG. 3  is merely illustrative. 
     Antenna  40  (i.e., the upper antenna of device  10  that is located in region  22  of  FIG. 1 ) may be formed using an inverted-F design. An illustrative inverted-F antenna arrangement is shown in  FIG. 4 . As shown in  FIG. 4 , inverted-F antenna  40  may include a ground such as ground  60  and an antenna resonating element such as antenna resonating element  66 . 
     Ground  60 , which may sometimes be referred to as a ground plane or ground plane element, may be formed from one or more conductive structures (e.g., planar conductive traces on printed circuit board  46 , internal structural members in device  10 , electrical components  44  on board  46 , radio-frequency shielding cans mounted on board  46 , housing structures such as portions of bezel  16 , etc.). 
     Antenna resonating element  66  may be have a main resonating element arm such as arm  62 , a feed leg such as leg F, and a short circuit leg such as leg S 1 . Legs S 1  and F may sometimes referred to as arms or branches of resonating element  66 . Short circuit leg S 1  may form a short circuit between antenna resonating element main arm  62  and ground  60 . Antenna  40  may be fed by coupling a radio-frequency transceiver circuit between positive antenna feed terminal  58  on antenna feed leg F and ground antenna feed terminal  54 . 
     In some device environments, an inverted-F antenna of the type shown in  FIG. 4  may consume more space than is desired. As shown in  FIG. 5 , space consumption may be minimized by providing antenna  40  with an antenna resonating element that has one or more bends. As shown in  FIG. 5 , antenna  40  may include a ground such as ground  60  and an antenna resonating element such as antenna resonating element  66 . Short circuit leg S 1  may connect arm  62  to ground  60 . Feed leg F may connect arm  62  to antenna feed terminal  58 . Main resonating element arm  62  may have a bend such as bend  64 . 
     Bend  64  may have any suitable angle (e.g., a right angle, an acute angle, an oblique angle, etc.). In the example of  FIG. 5 , bend  64  has a 180° angle (i.e., bend  64  makes a fold in arm  62 ). Due to the presence of bend  64 , arm  62  has two parallel segments  62 A and  62 B. 
     Arm portion  62 A and arm portion  62 B run parallel to each other in the example of  FIG. 5 , but this is merely illustrative. Antenna resonating element arm  62  may, in general, be provided with bends of different angles and with different numbers of bends. Accordingly, there may be two or more resonating element arm segments in arm  62  and one, two, or more than two corresponding bends in arm  62 . Arm  62  may also be provided with one or more separate branches, regions of locally increased or decreased width, or other features. These features may be used to improve the geometry of antenna  40  to accommodate design goals, to modify the frequency response of antenna  40 , etc. 
     It may be desirable for antenna  40  to exhibit satisfactory performance over multiple frequency bands. For example, it may be desirable for antenna  40  to handle a first communications band at 1575 MHz (e.g., for handling GPS signals) at a second communications band at 2.4 GHz (e.g., for handling Bluetooth® and IEEE 802.11 signals). An illustrative antenna configuration that may be used in device  10  to support multiband operation is shown in  FIG. 6 . 
     As shown in  FIG. 6 , antenna  40  may have an inverted-F configuration in which resonating element arm  62  is folded back on itself at bend  64 . Because of the presence of bend  64 , arm segments  62 A and  62 B run parallel to each other. Feed leg F may connect resonating element arm  62  to positive antenna feed terminal  58 . Antenna  40  may be fed using positive antenna feed terminal  58  and ground antenna feed terminal  54 . For example, a positive conductor in transmission line  52  may be coupled to positive antenna feed terminal  58  and a ground conductor in transmission line  52  may be coupled to ground antenna feed terminal  54  (and thereby to the conductive portions of ground  60  that are connected to ground antenna feed terminal  54 ). 
     Housing structures  16  may be used in forming some of antenna  40 . As shown in  FIG. 6 , housing structures  16  may include bezel segments  16 A- 1  and  16 A- 2  along the left edge of device  10 , bezel segment  16 C along the right edge of device  10 , bezel segment  16 B along the lower edge of device  10 , and bezel segments  16 D- 1  and  16 D- 2  along the upper edge of device  10 . 
     Short circuit leg S 1  may be formed using bezel segment  16 A- 1 . Segments  16 A- 1  and  16 A- 2  may be electrically connected at node  72  (i.e., segments  16 A- 1  and  16 A- 2  may be parts of an uninterrupted length of bezel  16 . Bezel segment  16 D- 1  may be used in forming main resonating element arm segment  62 A. Segment  62 B may be formed from a conductive metal trace formed on a dielectric member in the interior of housing  12  (as an example). Springs, welds, and other conductive members may be interposed at one or more locations along the length of arm  62  if desired. Gap  18  may separate bezel segment  16 D- 1  and bezel segment  16 D- 2 . The location of gap  18  may therefore define the length of  16 D- 1  and resonating arm segment  62 A. The length of resonating element arm segment  62 B may be defined by the size and shape of the conductive trace or other conductive structures that form segment  62 B. If desired, some or all of bezel segments  16 A- 2 ,  16 D- 2 ,  16 C, and  16 B may shorted to ground plane  60 . Some of all of these segments may also be used in forming additional antennas (e.g., a lower antenna for device  10 ). Ground plane  60  may be formed from traces on a printed circuit board, from conductive structures such as the structures associated with input-output port connectors, shielding cans, integrated circuits, traces on printed circuit boards, housing frame members, and other conductive materials. 
     The presence of short circuit leg S 2  in parallel with short circuit leg S 1  may help antenna  40  handle signals in multiple bands. The impact of short circuit leg S 2  may be understood with reference to the Smith chart of  FIG. 7 , which corresponds to antenna  40  in configurations with and without leg S 2 . In the Smith chart of  FIG. 7 , point  74  represents a 50 Ohm impedance (i.e., an impedance that is suitable for matching to a transmission line such as transmission line  52  of  FIG. 3 ). At frequencies in which there are substantial deviations from point  74 , antenna performance may be reduced due to impedance mismatches. At frequencies of antenna operation in which the distance to point  74  is minimized, impedance matching is generally satisfactory (i.e., the antenna will exhibit a resonance). 
     Curve  76  corresponds to the performance of antenna  40  in the absence of short circuit leg S 2 . Low band segment LB of curve  76  lies in a first communications band of interest (e.g., the 1575 MHz GPS band). High band segment HB lies in a second communications band of interest (e.g., the 2.4 GHz band that is associated with Bluetooth® and WiFi® signals). 
     In the absence of short circuit leg S 2 , low band segment LB may lie at a distance from point  74  that is larger than desired, while high band segment HB may be within an acceptably short distance from point  74 . To tune the impedance of antenna  40  so that both low band and high band performance are simultaneously satisfactory, short circuit leg S 2  may be included in antenna  40 . In the presence of short circuit leg S 2  there is an additional shunt inductance from arm  62  to ground  60  that lies in parallel with short circuit leg S 1 . This additional shunt inductance moves the position of low band segment LB to the location occupied by low band segment LB′ in the chart of  FIG. 7 . Segment LB′ is acceptably close to point  74 , so antenna  40  will exhibit satisfactory low band (GPS) performance when short circuit leg S 2  is present. Inclusion of short circuit leg S 2  will tend to alter the position of high band segment HB somewhat, but any impact on high band performance in antenna  40  is generally minimal in comparison to the improved low band performance associated with segment LB′. 
     Graphs showing how antenna  40  may perform both with and without short circuit leg S 2  are presented in  FIGS. 8 and 9 . In the graph of  FIG. 8 , standing wave ratio (SWR) values are plotted as a function of frequency for an antenna without short circuit leg S 2  (i.e., antenna  40  of  FIG. 5 ). In the graph of  FIG. 9 , standing wave ratio values are plotted as a function of frequency for an antenna in which short circuit leg S 2  is present (i.e., antenna  40  of  FIG. 6 ). 
     As shown in the graph of  FIG. 8 , an antenna without short circuit leg S 2  may exhibit a resonance in a second wireless communications band (i.e., a second band at frequency f 2  such as a Bluetooth®/WiFi® band at 2.4 GHz), but may exhibit no significant resonance in a first frequency band (i.e., a first band at a frequency f 1  such as a GPS frequency of 1575 Mz). Antennas of this type may be used to handle wireless communications in the second frequency band. 
     As shown in the graph of  FIG. 9 , an antenna with short circuit leg S 2  such as antenna  40  of  FIG. 6  may exhibit resonances in both a first band (i.e., a first band at a frequency f 1  such as a GPS frequency of 1575 Mz) and a second band (i.e., a second band at frequency f 2  such as a Bluetooth®/WiFi® band at 2.4 GHz). Because an antenna with a frequency response of the type shown in  FIG. 9  can handle radio-frequency signals in two bands, an antenna of this type is sometimes referred to as a multiband antenna or a dual band antenna. The use of an antenna that covers more than one band may avoid the need to provide multiple separate antenna structures, thereby minimizing the amount of space consumed within electronic device  10 . If desired, antenna  40  may be configured to handle more than two bands (e.g., three or more). The dual band example of  FIG. 9  is merely illustrative. 
     An illustrative arrangement that may be used in implementing antenna  40  of  FIG. 6  is shown in  FIG. 10 . As shown in  FIG. 10 , antenna  40  of  FIG. 10  may include a main antenna resonating element arm formed from resonating element arm segments  62 A and  62 B. Arm  62 A may be formed from bezel segment  16 D- 1 . Arm  62 B may be formed from a conductive trace on dielectric member  88 . Member  88  may be formed from plastic, glass, ceramic, composites, other materials, or combinations of these materials. One or more structures may be combined to form member  88 . The conductive material that forms arm segment  62 B on member  88  may be formed from a metal such as copper, copper plated with gold, etc. The metal may be formed directly on member  88  or may be fabricated as part of a flex circuit or other part that is attached to member  88  (e.g., using adhesive). 
     A conductive structure such as spring  78  may be used to electrically connect end  82  of the conductive trace on member  88  to end  84  of bezel segment  16 D- 1 . Spring  78  may be formed from metal and may be attached to end  84  of bezel segment  16 D- 1  using weld  80 . End  86  of spring  78  (i.e., the opposite end of spring  78  from the end at weld  80 ) may press against the conductive trace on member  88  to form an electrical connection. If desired, other connection arrangements may be used (e.g., involving solder, additional welds, fasteners, etc.). 
     In the  FIG. 10  arrangement, short circuit leg S 2  and feed leg F pass over or under resonating element arm segment  62 B without forming a direct electrical connection with resonating element arm segment  62 B (as shown schematically in  FIG. 6 ). Legs S 2  and F may be formed using screws, springs, or other suitable conductive structures. Short circuit leg S 1  may be formed from part of bezel  16  (i.e., bezel segment  16 A). Ground  60  may be formed using printed circuit board structures, parts of bezel  16 , other parts of the housing of device  10 , or other suitable conductive structures, as described in connection with  FIG. 6 . 
     Gap  18  may be filled with dielectric material  82  such as plastic, ceramic, epoxy, composites, glass, other dielectrics, or combinations of these materials. 
     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. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20100401
Publication Date: 20151013
Grant Date: 20151013
Priority Date: 20100401
Inventors: NICKEL JOSH
ZAVALA JUAN
ZHOU YIJUN
PASCOLINI MATTIA
SCHLUB ROBERT W.
CABALLERO RUBEN
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q1/243", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q9/0421", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/0421", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q5/364", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/48", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q5/364", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/0421", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q5/364", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q5/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/24", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q9/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/42", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 43614012