PATENT DOCUMENT

Publication Number: US-7688267-B2
Application Number: US-59375206-A
Country: US
Kind Code: B2

Title: Broadband antenna with coupled feed for handheld electronic devices

Abstract:
Broadband antennas and handheld electronic devices with broadband antennas are provided. A handheld electronic device may have a housing in which electrical components such as integrated circuits and a broadband antenna are mounted. The broadband antenna may have a ground element and a resonating element. The resonating element may have two arms of unequal length and may have a self-resonant element. The antenna may have a feed terminal connected to the self-resonant element and a ground terminal connected to the ground element. The self-resonant element may be near-field coupled to one of the arms of the resonating element. With one suitable arrangement, the self-resonant element may be formed using a conductive rectangular element that is not electrically shorted to the ground element or the arms of the resonating element. The antenna may operate over first and second frequency ranges of interest.

Claims:
1. A handheld electronic device antenna, comprising:
 a ground element; 
 a resonating element comprising a first arm having a first length, a second arm having a second length that is different than the first length, and a self-resonant element that is near-field coupled to the second arm, wherein the self-resonant element is not electrically shorted to the ground element; 
 an antenna ground terminal connected to the ground element; and 
 an antenna feed terminal connected to the self-resonant element. 
 
   
   
     2. The handheld electronic device antenna defined in  claim 1  further comprising:
 a flex circuit mounting structure on which the resonating element is formed. 
 
   
   
     3. The handheld electronic device antenna defined in  claim 1  further comprising:
 a planar mounting structure on which the ground element and the resonating element are formed. 
 
   
   
     4. The handheld electronic device antenna defined in  claim 1  further comprising:
 a mounting structure on which the resonating element and at least part of the ground element are formed; 
 ground extension portions on the mounting structure that surround the resonating element on at least three sides. 
 
   
   
     5. The handheld electronic device antenna defined in  claim 1  further comprising:
 a mounting structure on which the resonating element and at least part of the ground element are formed; 
 ground extension portions on the mounting structure that surround the resonating element on at least three sides; and 
 a conductive handheld electronic device housing in which the mounting structure is mounted. 
 
   
   
     6. A portable electronic device comprising:
 a housing; 
 at least one integrated circuit mounted in the housing that generates data for wireless transmission, and that processes data that is wirelessly received by the electronic device; and 
 wireless communications circuitry mounted in the housing that communicates with the integrated circuit, wherein the wireless communications circuitry comprises an antenna comprising a ground element formed at least partly from conductive shielding that surrounds the integrated circuit and a resonating element, wherein the resonating element comprises a first arm having a first length, a second arm having a second length that is different than the first length, and a self-resonant element that is near-field coupled to the second arm, and wherein the ground element surrounds the resonating element on at least three sides. 
 
   
   
     7. The portable electronic device defined in  claim 6  wherein a ground terminal is connected to the ground element, wherein a feed terminal is connected to the self-resonant element, wherein the self-resonant element comprises a conductive material that is not electrically shorted to the ground element, and wherein the portable electronic device is a wearable portable electronic device. 
   
   
     8. The portable electronic device defined in  claim 6  wherein a ground terminal is connected to the ground element, wherein a feed terminal is connected to the self-resonant element, and wherein the antenna comprises a shorting conductive portion that electrically connects the self-resonant element to the ground so that the self-resonant element is parallel fed. 
   
   
     9. The portable electronic device defined in  claim 6  wherein the housing has a planar face, wherein a portion of the ground element is mounted to the planar face, and wherein the portable electronic device is a miniature electronic device. 
   
   
     10. The portable electronic device defined in  claim 6  wherein the housing has a planar face, wherein a portion of the ground element is mounted to the planar face, and wherein the resonating element is separated from the portion of the ground element that is mounted to the planar face by at least 5 mm in a dimension that is perpendicular to the planar face, the portable electronic device further comprising a microphone located between the planar rear face and the resonating element, wherein the portable electronic device comprises at least a media player. 
   
   
     11. A handheld electronic device comprising:
 a housing; 
 a broadband antenna comprising a ground element and a resonating element, wherein at least a portion of the ground element and the resonating element lie in a common plane, the resonating element comprising a first arm having a first length, a second arm having a second length that is different than the first length, and a self-resonant element that is near-field coupled to the second arm, wherein the self-resonant element is not electrically shorted to the ground element; and 
 at least one integrated circuit that is located within the housing adjacent to the portion of the ground element that lies in the common plane, wherein an antenna ground terminal is connected to the ground element and wherein an antenna feed terminal is connected to the self-resonant element. 
 
   
   
     12. The handheld electronic device defined in  claim 11  wherein the housing comprises:
 a conductive portion; 
 a plastic cap adjacent to the resonating element. 
 
   
   
     13. The handheld electronic device defined in  claim 11  further comprising a flexible circuit substrate on which the resonating element and at least a portion of the ground element are formed. 
   
   
     14. The handheld electronic device defined in  claim 11  further comprising a coaxial cable having a center conductor that is connected to the self-resonant element and having an outer conductor that is connected to the ground element. 
   
   
     15. The handheld electronic device defined in  claim 11  wherein the first and second arms comprise metal, wherein the first length is shorter than the second length, and wherein the self-resonant element is located adjacent to the second arm and is separated from the second arm by a gap of at least 1 mm. 
   
   
     16. A handheld electronic device comprising:
 a housing; 
 an integrated circuit; 
 an antenna comprising a ground element, and a resonating element, an antenna ground terminal, and an antenna feed terminal, wherein the resonating element comprises an F-shaped element and a self-resonant element, wherein the F-shaped element and the self-resonant element are near-field coupled, wherein the self-resonant element is rectangular and is separated from the F-shaped element by a gap, wherein the antenna ground terminal is connected to the ground element, wherein the antenna feed terminal is connected to the self-resonant element, and wherein the self-resonant element comprises a conductive material that is not electrically shorted to the ground element. 
 
   
   
     17. The handheld electronic device defined in  claim 16  further comprising a radio-frequency path that connects the integrated circuit to the antenna, wherein the radio-frequency path comprises a first conductor connected to the self-resonant element and a second conductor connected to the ground element. 
   
   
     18. The handheld electronic device defined in  claim 16  further comprising conductive radio-frequency shielding surrounding the integrated circuit, wherein the ground element is formed at least partly from the radio-frequency shielding. 
   
   
     19. The handheld electronic device defined in  claim 16  wherein the conductive material comprises metal. 
   
   
     20. A broadband antenna in a handheld electronic device that has a planar front surface, comprising:
 a ground element comprising a planar portion that is parallel to the planar front surface; and 
 a resonating element comprising first and second arms of unequal length and comprising a rectangular element that is not electrically shorted to the ground element, that is not electrically shorted to the first and second arms, and that is near-field coupled to the second arm of the resonating element, wherein the ground element comprises three rectangular ground extension portions that together surround the resonating element on three sides. 
 
   
   
     21. The broadband antenna defined in  claim 20  wherein the three rectangular ground extension portions and the planar portion of the ground element surround the resonating element on four sides. 
   
   
     22. The broadband antenna defined in  claim 20  wherein the resonating element comprises metal and wherein the integrated circuit generates data that is transmitted through the antenna in a first frequency range that includes an 850 MHz communications band and a 900 MHz communications band and a second frequency range that includes a 1800 MHz communications band, a 1900 MHz communications band, a 2170 MHz communications band, and a 2400 MHz communications band. 
   
   
     23. The broadband antenna defined in  claim 20  further comprising an antenna feed terminal that is connected to the rectangular element, wherein the integrated circuit generates data that is transmitted through the antenna in first and second non-overlapping frequency ranges. 
   
   
     24. An antenna in a handheld electronic device having a housing, comprising:
 a ground element comprising at least one planar portion; and 
 a resonating element comprising a first arm having a first length, a second arm having a second length that is longer than the first length, and a self-resonant element that is near-field coupled to the second arm, wherein the second arm and the self-resonant element are substantially rectangular and are separated by a gap, wherein an antenna feed terminal is connected to the self-resonant element, wherein an antenna ground terminal is connected to the planar portion of the ground element, wherein the ground element comprises ground extension portions, and wherein the planar portion and the ground extension portions surround the first arm, the second arm, and the self-resonant element. 
 
   
   
     25. The antenna defined in  claim 24  wherein the first arm, the second arm, and the self-resonant element are located in a common plane on a mounting structure formed from dielectric. 
   
   
     26. The antenna defined in  claim 24  further comprising a mounting structure comprising printed circuit board materials on which at least part of the ground element is formed. 
   
   
     27. The antenna defined in  claim 24  wherein the resonating element comprises metal and wherein the first arm, the second arm, and the self-resonant element each have a length and a height, wherein the lengths are each less than 10 cm and wherein the heights are between 3 mm and 10 mm.

Description:
BACKGROUND 
   This invention relates generally to antennas, and more particularly, to broadband antennas in wireless handheld electronic devices. 
   Handheld electronic devices are often provided with wireless capabilities. Handheld electronic devices with wireless capabilities use antennas to transmit and receive radio-frequency signals. For example, cellular telephones contain antennas that are used to handle radio-frequency communications with cellular base stations. Handheld computers often contain short-range antennas for handling wireless connections with wireless access points. Global positioning system (GPS) devices typically contain antennas that are designed to operate at GPS frequencies. 
   As technology advances, it is becoming possible to combine multiple functions into a single device and to expand the number of communications bands a single device can handle. For example, it is possible to incorporate a short-range wireless capability into a cellular telephone. It is also possible to design cellular telephones that cover multiple cellular telephone bands. 
   The desire to cover a wide range of radio frequencies presents challenges to antenna designers. It is typically difficult to design antennas that cover a wide range of communications bands while exhibiting superior radio-frequency performance. This is particularly true when designing antennas for handheld electronic devices where antenna size and shape can be particularly important. 
   As a result of these challenges, conventional handheld devices that need to cover a large number of communications bands tend to use multiple antennas, antennas that are undesirably large, antennas that have awkward shapes, or antennas that exhibit poor efficiency. 
   It would therefore be desirable to be able to provide an improved broadband antenna for a handheld electronic device. 
   SUMMARY 
   In accordance with the present invention, broadband antennas and handheld electronic devices with broadband antennas are provided. A handheld electronic device with a broadband antenna may be cellular telephone with integrated music player capabilities, a personal digital assistant, or any other suitable handheld electronic device. The handheld device may include components such as integrated circuits. The integrated circuits may be encased in conductive materials, such as metal radio-frequency shielding. 
   A broadband antenna may include a resonating element and a ground element. The resonating element may have two conductive arms and a self-resonant element. An antenna feed terminal may be connected to the self-resonant element and an antenna ground terminal may be connected to the ground element. The self-resonant element may be electromagnetically coupled to at least one of the two conductive arms in the resonating element through near-field interactions. The self-resonant element may be separated from the rest of the resonating element by dielectric gaps. With one suitable arrangement, the self-resonant element is not electrically shorted to the ground element or the two conductive arms. If desired, the self-resonant element may be parallel fed by connecting one end of the self-resonant element to the ground element with a strip of conductor. 
   The ground element may be formed at least partly from the radio-frequency shielding or other conductive portion that surrounds the integrated circuits. If desired, the resonating element may be formed on a flex circuit or other suitable flexible or rigid substrate. The flex circuit may be mounted on or within a support structure and may be mechanically and electrically attached to a grounded circuit board. 
   The broadband antenna and other components in the handheld electronic device may be mounted within a housing. The housing may be formed from dielectric materials, conductive materials, or a combination of dielectric and conductive materials. With one suitable arrangement, the housing is formed partially from metal and has a plastic cap in the vicinity of the resonating element. 
   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 handheld electronic device with a broadband antenna in accordance with an embodiment of the present invention. 
       FIG. 2  is a schematic diagram of an illustrative handheld electronic device and illustrative equipment with which the handheld electronic device may interact wirelessly in accordance with an embodiment of the present invention. 
       FIG. 3  is a schematic diagram of illustrative wireless circuitry for a handheld electronic device in accordance with an embodiment of the present invention. 
       FIG. 4  is a plan view of an illustrative broadband antenna in accordance with an embodiment of the present invention. 
       FIG. 5  is a perspective view of an illustrative broadband antenna in accordance with an embodiment of the present invention. 
       FIG. 6  is a cross-sectional side view of an illustrative handheld electronic device containing electronic components and an illustrative broadband antenna in accordance with an embodiment of the present invention. 
       FIG. 7  is a diagram of an illustrative asymmetrical dipole antenna in accordance with an embodiment of the present invention. 
       FIG. 8  is a diagram of an illustrative efficiency versus frequency characteristic for an asymmetrical dipole antenna of the type shown in  FIG. 7  in accordance with an embodiment of the present invention. 
       FIG. 9  is a diagram of an illustrative asymmetric dipole antenna having parallel antenna elements in accordance with an embodiment of the present invention. 
       FIG. 10  is a diagram of an illustrative parallel-fed asymmetric dipole antenna in accordance with an embodiment of the present invention. 
       FIG. 11  is a diagram of an illustrative asymmetric dipole antenna having a larger ground plane. 
       FIG. 12  is a diagram of an illustrative asymmetric dipole antenna having two resonating element arms of unequal length in accordance with an embodiment of the present invention. 
       FIG. 13  is a diagram of another illustrative asymmetric dipole antenna having two resonating element arms of unequal length in accordance with an embodiment of the present invention. 
       FIG. 14  is a diagram of an illustrative antenna with a center-fed resonating element in accordance with an embodiment of the present invention. 
       FIG. 15  is a graph of an illustrative efficiency versus frequency characteristic for an antenna of the type shown in  FIG. 14  in accordance with an embodiment of the present invention. 
       FIG. 16  is a diagram illustrating how two conductive elements can be near-field coupled. 
       FIG. 17  is a graph of an illustrative efficiency versus frequency characteristic for an asymmetric dipole antenna of the type shown in  FIG. 11  in accordance with an embodiment of the present invention. 
       FIG. 18  is a graph of an illustrative efficiency versus frequency characteristic for an asymmetric dipole antenna of the types shown in  FIGS. 12 and 13  in accordance with an embodiment of the present invention. 
       FIG. 19  is a graph of an illustrative efficiency versus frequency characteristic for a broadband antenna with a coupled feed in accordance with an embodiment of the present invention. 
       FIG. 20  is a graph of measured standing-wave-ratio values versus frequency for a broadband antenna of the type shown in  FIG. 4  in accordance with an embodiment of the present invention. 
       FIGS. 21 ,  22 , and  23  are graphs of measured antenna efficiency versus frequency for a broadband antenna of the type shown in  FIG. 4  in accordance with an embodiment of the present invention. 
       FIG. 24  is a diagram of an illustrative broadband antenna with a coupled feed in accordance with an embodiment of the present invention. 
       FIG. 25  is a diagram of another illustrative broadband antenna with a coupled feed in accordance with an embodiment of the present invention. 
       FIG. 26  is a cross-sectional side view of an illustrative handheld electronic device having an illustrative three-dimensional broadband antenna with a coupled feed in accordance with an embodiment of the present invention. 
   

   DETAILED DESCRIPTION 
   An illustrative portable electronic device in accordance with the present invention is shown in  FIG. 1 . Portable electronic devices such as illustrative portable electronic device  10  may be small portable computers such as those sometimes referred to as ultraportables. Portable devices may also be somewhat smaller devices. Examples of smaller portable devices include wrist-watch devices, pendant devices, headphone and earpiece devices, and other wearable and miniature devices. With one particularly suitable arrangement, the portable electronic devices are handheld electronic devices. The use of handheld devices is generally described herein as an example, although any suitable electronic device may be used 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. The handheld devices of the invention may also be hybrid devices that combine the functionality of multiple conventional devices. Examples of hybrid handheld devices include a cellular telephone that includes media player functionality, a gaming device that includes a wireless communications capability, a cellular telephone that includes game and email functions, and a handheld device that receives email, supports mobile telephone calls, and supports web browsing. These are merely illustrative examples. Device  10  may be any suitable portable or handheld electronic device. 
   Device  10  includes housing  12  and includes at least one antenna of a type that is sometime referred to as a broadband antenna. Housing  12 , which is sometimes referred to as a case, may be formed of any suitable materials including, plastic, wood, glass, ceramics, metal, or other suitable materials, or a combination of these materials. In some situations, all or part of case  12  may be formed from dielectric or other low-conductivity material, so that the operation of conductive antenna elements that are located in proximity to case  12  is not disrupted. In other situations, case  12  may be formed from metal elements that serve as ground for the broadband antenna. 
   The broadband antenna in device  10  has a resonating element (sometimes referred to as a radiating element or a positive element) and has a ground element (sometimes referred to as a negative element or ground). The ground and the resonating element of the antenna are coupled to a corresponding ground terminal and feed terminal associated with a radio-frequency transceiver in handheld device  10 . 
   Handheld electronic device  10  may have input-output devices such as a display screen  16 , buttons such as button  23 , user input control devices  18  such as button  19 , and input-output components such as port  20  and input-output jack  21 . Display screen  16  may be, for example, a liquid crystal display (LCD), an organic light-emitting diode (OLED) display, a plasma display, or multiple displays that use one or more different display technologies. As shown in the example of  FIG. 1 , display screens such as display screen  16  can be mounted on front face  22  of handheld electronic device  10 . Front face  22  and the rear face of device  10  may be planar. If desired, displays such as display  16  can be mounted on the rear face of handheld electronic device  10 , on a side of device  10 , on a flip-up portion of device  10  that is attached to a main body portion of device  10  by a hinge (for example), or using any other suitable mounting arrangement. 
   A user of handheld device  10  may supply input commands using user input interface  18 . User input interface  18  may include buttons (e.g., alphanumeric keys, power on-off, power-on, power-off, and other specialized buttons, etc.), a touch pad, pointing stick, or other cursor control device, a touch screen (e.g., a touch screen implemented as part of screen  16 ), or any other suitable interface for controlling device  10 . Although shown schematically as being formed on the top face  22  of handheld electronic device  10  in the example of  FIG. 1 , user input interface  18  may generally be formed on any suitable portion of handheld electronic device  10 . For example, a button such as button  23  (which may be considered to be part of input interface  18 ) or other user interface control may be formed on the side of handheld electronic device  10 . Buttons and other user interface controls can also be located on the top face, rear face, or other portion of device  10 . If desired, device  10  can be controlled remotely (e.g., using an infrared remote control, a radio-frequency remote control such as a Bluetooth remote control, etc.). 
   Handheld device  10  may have ports such as bus connector  20  and jack  21  that allow device  10  to interface with external components. Typical ports include power jacks to recharge a battery within device  10  or to operate device  10  from a direct current (DC) power supply, data ports to exchange data with external components such as a personal computer or peripheral, audio-visual jacks to drive headphones, a monitor, or other external audio-video equipment, etc. The functions of some or all of these devices and the internal circuitry of handheld electronic device can be controlled using input interface  18 . 
   Components, such as display  16  and user input interface  18 , may cover most of the available surface area on the front face  22  of device  10  (as shown in the example of  FIG. 1 ) or may occupy only a small portion of the front face  22 . Because electronic components such as display  16  often contain large amounts of metal (e.g., metal used as radio-frequency shielding), the location of these components relative to the antenna elements in device  10  should generally be taken into consideration. Suitably chosen locations for the antenna elements and electronic components of the device will allow the antenna of handheld electronic device  10  to function properly without being disrupted by the electronic components. 
   A schematic diagram of an illustrative handheld electronic device of the type that may contain a broadband antenna is shown in  FIG. 2 . Handheld device  10  may be 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 portable electronic device. 
   As shown in  FIG. 2 , handheld device  10  may include storage  34 . Storage  34  may include one or more different types of storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or electrically-programmable-read-only memory), volatile memory (e.g., battery-based static or dynamic random-access-memory), etc. 
   Processing circuitry  36  may be used to control the operation of device  10 . Processing circuitry  36  may be based on a processor such as a microprocessor and other suitable integrated circuits. 
   Input-output devices  38  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. Display screen  16  and user input interface  18  of  FIG. 1  are examples of input-output devices  38 . 
   Input-output devices  38  can include user input-output devices  40  such as buttons, touch screens, 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 user input devices  40 . Display and audio devices  42  may include liquid-crystal display (LCD) screens, light-emitting diodes (LEDs), and other components that present visual information and status data. Display and audio devices  42  may also include audio equipment such as speakers and other devices for creating sound. Display and audio devices  42  may contain audio-video interface equipment such as jacks and other connectors for external headphones and monitors. 
   Wireless communications devices  44  may include communications circuitry such as radio-frequency (RF) transceiver circuitry formed from one or more integrated circuits, power amplifier circuitry, passive RF components, antennas, such as a broadband antenna of the type described in connection with  FIG. 1 , and, if desired, additional antennas, and other circuitry for handling RF wireless signals. Wireless signals can also be sent using light (e.g., using infrared communications). 
   Device  10  can communicate with external devices, such as accessories  46  and computing equipment  48 , as shown by paths  50 . Paths  50  may include wired and wireless paths. Accessories  46  may include headphones (e.g., a wireless cellular headset or audio headphones) and audio-video equipment (e.g., wireless speakers, a game controller, or other equipment that receives and plays audio and video content). Computing equipment  48  may be a server from which songs, videos, or other media are downloaded over a cellular telephone link or other wireless link. Computing equipment  48  may also be a local host (e.g., a user&#39;s own personal computer), from which the user obtains a wireless download of music or other media files. 
   Wireless communications devices  44  may be used to cover communications frequency bands such as the cellular telephone bands at 850 MHz, 900 MHz, 1800 MHz, and 1900 MHz, data service bands such as the 3G data communications band at 2170 MHz band (commonly referred to as UMTS or Universal Mobile Telecommunications System), the WiFi® (IEEE 802.11) band at 2.4 GHz, and the Bluetooth® band at 2.4 GHz. These are merely illustrative communications bands over which wireless devices  44  may operate. Additional bands are expected to be deployed in the future as new wireless services are made available. Wireless devices  44  may be configured to operate over any suitable band or bands to cover any existing or new services of interest. If desired, multiple antennas may be provided in wireless devices  44  to cover more bands or one or more antennas may be provided with wide-bandwidth resonating elements to cover multiple communications bands of interest. An advantage of using a broadband antenna design that covers multiple communications bands of interest is that this type of approach makes it possible to reduce device complexity and cost and to minimize the amount of a handheld device that is allocated towards antenna structures. 
   A broadband design may be used for one or more antennas in wireless devices  44  when it is desired to cover a relatively larger range of frequencies without providing numerous individual antennas or using a tunable antenna arrangement. If desired, a broadband antenna design may be made tunable to expand its bandwidth coverage or may be used in combination with additional antennas. In general, however, broadband designs tend to reduce or eliminate the need for multiple antennas and tunable configurations. 
   Illustrative wireless communications devices  44  that are based on a broadband antenna arrangement are shown in  FIG. 3 . As shown in  FIG. 3 , wireless communications devices  44  include at least one broadband antenna  62 . Data signals that are to be transmitted by device  10  may be provided to baseband module  52  (e.g., from processing circuitry  36  of  FIG. 2 ). Baseband module  52  may provide data to be transmitted to transmitter circuitry within transceiver circuits  54 . The transmitter circuitry may be coupled to power amplifier circuitry  56  via path  55 . 
   During data transmission, power amplifier circuitry  56  may boost the output power of transmitted signals to a sufficiently high level to ensure adequate signal transmission. Radio-frequency (RF) output stage  57  may contain radio-frequency switches and passive elements such as duplexers and diplexers. The switches in the RF output stage  57  may, if desired, be used to switch devices  44  between a transmitting mode and a receiving mode. Duplexer and diplexer circuits and other passive components in RF output stage may be used to route input and output signals based on their frequency. 
   Matching circuit  60  may include a network of passive components such as resistors, inductors, and capacitors and ensures that broadband antenna  62  is impedance matched to the rest of the circuitry  44 . Wireless signals that are received by antenna  62  are passed to receiver circuitry in transceiver circuitry  54  over a path such as path  64 . 
   An illustrative arrangement that may be used for broadband antenna  62  is shown in  FIG. 4 . As shown in  FIG. 4 , antenna  62  may include ground element  66  and resonating element  68 . Signals may be conveyed between electrical components in device  10  and antenna  62  using a coaxial cable or other suitable radio-frequency (RF) signal path. With one illustrative arrangement, a coaxial cable center conductor can be connected to antenna feed terminal connection point  80  and a coaxial cable outer conductor can be connected to antenna ground terminal connection point  78 . This is merely illustrative. In general, signals may be provided to antenna  62  and may be received from antenna  62  using any suitable antenna terminal arrangement. 
   Resonating element  68  of  FIG. 4  can have two arms  70  and  72  of unequal length and a self-resonant antenna element  74 . Arms  70  and  72  can form an “F” shape and may sometimes be referred to collectively as a F-shaped resonating element or an F-shaped antenna element. Feed terminal  80  can be connected to self-resonant antenna element  74 , so antenna element  74  (and more generally resonating element  68 ) may sometimes be referred to as an antenna feed element or feed. 
   As shown in the example of  FIG. 4 , ground  66  can have a rectangular ground plane portion, as indicated by rectangular dotted-line box  82 . Additional ground portions can extend the ground around the periphery of the resonating element and surround three sides of the resonating element. The additional ground portions can include two side ground extension portions and a top ground extension portion. The locations of the side ground extension portions are indicated by dotted-line boxes  84  and  88 . The location of the top ground extension portion is indicated by dotted-line box  86 . In the example of  FIG. 4 , ground portions  82 ,  84 ,  86 , and  88  of ground  66  surround all four sides of resonating element  68 . This creates an overall substantially rectangular shape for antenna  62  that has ground portions on all four of its edges. An advantage of this type of grounding arrangement is that it reduces, or even avoids, undesirable antenna-housing interactions that might otherwise arise when antenna  62  is installed in conductive housings  12  (e.g., a grounded metal housing). 
   As shown in  FIG. 5 , when antenna  62  is installed in housing  12 , antenna edge  90  can be adjacent to housing side  92 , antenna edge  94  can be adjacent to housing side  96 , antenna edge  98  can be adjacent to housing side  100 , and antenna edge  102  can be adjacent to housing side  104 . If sides  92 ,  96 ,  100 , and  104  are conductive, it may be desirable to use a grounding arrangement for antenna  62  in which portions of ground  66  surround the periphery of the antenna  62  as described in connection with  FIG. 4 , thereby avoiding undesirable conditions in which portions of the resonating element directly abut the housing. The arrangement of  FIGS. 4 and 5  is, however, merely illustrative. Any suitable grounding arrangement may be used for antenna  62  if desired. 
   Illustrative antenna  62  of  FIGS. 4 and 5  uses a planar form factor. This is merely illustrative. Antenna  62  may, if desired, be formed using three-dimensional antenna structures, such as structures in which ground  66  is located in a different plane than resonating element  68 . When a three-dimensional antenna structure is used, device  10  can sometimes be configured to house a greater number of electronic components. When more electronic components are included in device  10 , device  10  can provide more functionality to a user. 
   In the example of  FIG. 5 , antenna  62  can be formed from patterned conductor attached to a mounting structure  106 . The patterned conductor can be formed on the top of mounting structure  106  or on both sides of mounting structure  106  (e.g., using an arrangement in which a mirror image of the top-side patterned conductor is formed on the bottom side of the mounting structure). If a double-sided arrangement is desired, conductive vias may be used to electrically connect the conductors on the top and bottom surfaces of mounting structure  106 . 
   Mounting structure  106  may be any suitable mounting structure for proving physical support for elements  66  and  68 . Suitable mounting structures include mounting structures formed from circuit board materials, ceramics, glass, plastic, or other dielectrics. The mounting structure  70  may, if desired, be formed from part of housing  12  ( FIG. 1 ). Antenna components such as ground  66  may also be formed using conductive elements in device  10 , such as conductive radio-frequency conductive shielding that surrounds electronic components in device  10 . When such components are used to form ground  66 , a mounting structure such as mounting structure  106  can be used to provide physical support for resonating element  66 . 
   Suitable circuit board materials for mounting structure  106  include, for example, paper impregnated with phonolic resin, resins reinforced with glass fibers such as fiberglass mat impregnated with epoxy resin (sometimes referred to as FR-4), plastics, polytetrafluoroethylene, polystyrene, polyimide, and ceramics. Mounting structure  106  may be formed from a combination of any number of these materials or other suitable materials. Mounting structure  106  may be flexible or rigid or may have both flexible and rigid portions. Ground  66  and resonating element  68  may be formed from any suitable conductors such as silver, gold, copper, brass, other metals, or other conductive materials. These are merely illustrative examples. In general, antenna components, such as resonating element  68  and ground element  66 , may be formed using any suitable conductive antenna materials and mounting structures. 
   Ground element  66  and resonating element  68  may be mounted so that they lie in substantially the same plane, as shown in  FIGS. 4 and 5 . In three-dimensional antenna arrangements, some or all of ground  66  may also be extended into other planes. In the two-dimensional example of  FIGS. 4 and 5 , ground element  66  and resonating element  68  can lie in a common plane that contains the surface of mounting structure  106 , as shown in  FIG. 5 . 
   The dimensions of the components of antenna  62  may be selected based on the desired frequency ranges of operation for antenna  62 . Self-resonant element  74  has peak efficiency at the frequency at which its length corresponds to about a quarter of a wavelength. The size of ground element  66  may be selected so as to provide sufficient space in device  10  for mounting electronic components. 
   As shown in  FIG. 4 , the lengths of the antenna elements may be measured along a dimension parallel to axis  108 , while the heights of the antenna elements may be measured along a dimension parallel to axis  110 . In one illustrative arrangement, arm  70  has a height of about 5 mm and a length of about 4 cm, arm  72  has a height of about 1 cm and a length of about 5 cm, self-resonant element  74  has a height of about 4 mm and a length of about 4.5 cm. The gaps between the long edges of the conductive portions of resonating element  68  may be about 1-3 mm (e.g., at least 1 mm, at least 2 mm, at least 3 mm, etc.). These gaps are made up of air, circuit board material, or other suitable dielectric materials. 
   Although a range of possible dimensions may be used for arm  70 , arm  72 , and self-resonant element  74 , the constraints imposed by convenient sizes for handheld device  10  and the desired frequency bands for antenna operation generally lead to the lengths of these antenna components being less than 10 cm and the heights of these antenna elements being between about 3 mm and 10 mm. 
   It is generally desirable to avoid locating large amounts of grounded conductor too close to resonating element  68 . This consideration affects the layout used for device  10 . A cross-sectional view of an illustrative arrangement that may be used for device  10  without disturbing the proper operation of device  10  is shown in  FIG. 6 . In the example of  FIG. 6 , electrical components  112  can be located near front face  22  of device  10  and antenna  62  can be located near back face  114  of device  10 . Electrical components  112  typically include components, such as speakers, cameras, microphones, batteries, integrated circuits, keypads and other user control interfaces, connectors such as input-output jacks and power jacks, status indicators such as light-emitting diodes, displays such as liquid crystal displays, etc. 
   To avoid radio-frequency interference, some or all of components  112  may be surrounded with radio-frequency shielding. For example, integrated circuits in device  10  may be surrounded by copper ground conductors. Other components may contain large conductive portions (e.g., for grounding). Components  112  with radio-frequency shielding conductor or other large amounts of conductor are preferably mounted away from resonating element  68  (e.g., adjacent to ground  66 ), so as not to interfere with proper operation of antenna  62 . Components  112  with less conductive material or which need to be at end  69  of device  10  for proper operation (e.g., a microphone) can be located in the vicinity of resonating element  68 . If desired, the region under resonating element  68  (in the orientation of  FIG. 6 ) may be left empty. With this type of arrangement, air fills the region under resonating element  68 . 
   Antenna  62  may provide coverage over at least two frequency ranges of interest. The two frequency ranges may be non-overlapping. With one suitable arrangement, antenna  62  operates over a first frequency range of interest that covers cellular telephone bands such as the 850 MHz and 900 MHz bands and operates over a second frequency range of interest that covers cellular telephone bands such as the 1800 MHz and 1900 MHz bands, and data bands including the 2170 MHz data band (used for 3G data services) and the 2.4 GHz data band (used for WiFi and Bluetooth). These are merely examples of suitable frequency ranges in which antenna  62  may operate. Antenna  62  may operate in other suitable frequency ranges if desired (e.g., by modifying the sizes and relative spacing of the antenna elements in antenna  62 ). 
   The way in which the components of antenna  62  work with each other to provide satisfactory operation over the first and second frequency ranges is described in connection with  FIGS. 7-19 . 
     FIG. 7  shows an asymmetric dipole antenna  116 . Antenna  116  can have ground element  120  and resonating element  118 . Antenna  116  can have feed terminal  122  and ground terminal  124 . 
   Asymmetric dipole antennas of the type shown in  FIG. 7  exhibit efficiency versus frequency characteristics of the type shown in  FIG. 8 . As shown in  FIG. 8 , antenna  116  can operate satisfactorily in two frequency ranges—a first frequency range centered about a frequency f 0  and a second frequency range centered about a frequency 2f 0 . 
   As shown in  FIG. 9 , antenna  116  can continue to function, even if the resonating element  118  and ground element  120  are arranged to be parallel to each other. In the arrangement of  FIG. 9 , terminals  122  and  124  can provide signals to the ends of elements  118  and  120 . This type of arrangement is therefore sometimes referred to as an “end fed” antenna. Because elements  118  and  120  are not shorted together, this type of arrangement is also sometimes referred to as a “series fed” antenna. 
   In practice, it can be difficult to construct satisfactory antennas using a series-fed end-fed architecture. As a result, antennas sometimes use a parallel feed architecture of the type shown in  FIG. 10 . The antenna  116  of  FIG. 10  is shorted with shorting conductor  126  at the ends of elements  118  and  120  and is parallel fed through terminals  122  and  124  that are located a distance X from the antenna&#39;s shorted end. Use of the parallel-fed end-fed antenna arrangement of  FIG. 10  can allow an antenna designer to more easily satisfy antenna design criteria. For example, an antenna designer can match the antenna&#39;s impedance to the impedance of the coaxial cable or other radio-frequency (RF) signal path that is used to connect the antenna to an associated transceiver by appropriate selection of the distance X. Parallel-fed end-fed antennas are also more tolerant of large mismatches between the lengths of elements  118  and  120  than series-fed end-fed antennas, which provides an antenna designer with greater leeway when designing an antenna to cover certain desired frequency ranges. Conventional cellular telephones are sometimes constructed using an arrangement of the type shown in  FIG. 10  in which elements  118  and  120  form conductive sheets that extend along a dimension that is into the page in the orientation of  FIG. 10 . 
   As shown in  FIG. 11 , the size of ground element  120  in antenna  116  can be enlarged to form a rectangle while the size of resonating element  118  is maintained the same. The theory of operation for antenna  116  of  FIG. 11  is basically the same as antenna  116  in  FIG. 10 . 
     FIG. 12  shows an arrangement in which resonating element  118  of antenna  116  has been provided with two arms  126  and  128 . Because there are two “lengths” associated with the resonating element  118 , antenna  116  of  FIG. 12  can cover a wider frequency range than antenna  116  of the type shown in  FIG. 11 . Arm  126  can cause antenna  116  to resonate in first and second frequency ranges centered about f 0  and 2f 0 , respectively. Arm  128  causes antenna  116  to resonate in first and second frequency ranges centered about f 0 ′ and 2f 0 ′, respectively. Because both arm  126  and arm  128  contribute to the performance of antenna  116 , in practice, antenna  116  can exhibit a frequency response that is a superposition of the response contributed by arm  126  and the response contributed by arm  128 . The first frequency range covered by antenna  116  therefore encompasses both the range centered about f 0  and the range centered about f 0 ′. Similarly, the second frequency range of operation can cover the ranges centered about 2f 0  and 2f 0 ′. 
   In antenna  116  of  FIG. 12 , resonating element  118  is not surrounded by ground  120 . This type of arrangement may be satisfactory in some mounting arrangements (e.g., those in which the walls of a device housing are not formed from grounded metal or other such conductive structures). 
   In the arrangement of  FIG. 13 , resonating element  118  is surrounded by ground  120 , which makes antenna  116  suitable for installation in devices that have grounded side walls that abut the antenna. 
   Antenna  130  of  FIG. 14  can have ground  132  and resonating element  134 . Signals can be provided to antenna  130  using feed terminal  136  and ground terminal  138 . Because feed terminal  136  can be connected to the center of resonating element  134 , antennas such as antenna  130  are sometimes referred to as center-fed antennas. Elements such as element  134  may sometimes be referred to as self-resonant antenna elements. 
   Center-fed antennas of the type shown in  FIG. 14  exhibit efficiency versus frequency characteristics of the type shown in  FIG. 15 . As shown in  FIG. 15 , antenna  130  operates satisfactorily in a single frequency range centered about frequency f a . Frequency f a  is related to the length of self-resonant element  134  (i.e., the length of element  134  is about a quarter of a wavelength at frequency f a ). 
   As shown in  FIG. 4 , the resonating element of antenna  62  of the present invention has multiple arms  70  and  72  that operate in accordance with the principles discussed in connection with the operation of antenna  116  of  FIG. 13  and self-resonant element  74  that operates in accordance with the principles discussed in connection with the operation of antenna  130  of  FIG. 14 . However, unlike antenna  116  of  FIG. 13 , which has feed terminal  122  connected to arm  128 , antenna  62  of the present invention can have a feed terminal that is not directly electrically connected to arms  70  and  72 . Rather, antenna  62  can have feed terminal  80 , which is electrically connected to self-resonant element  74 . In the illustrative arrangement of  FIG. 4 , self-resonant element  74  may not be electrically shorted to arms  70  and  72  and ground  66  (i.e., there is an open circuit between element  74  and arms  70  and  72  and ground  66  in the  FIG. 4  configuration). 
   Self-resonant element  74  can serve as an antenna (as described in connection with antenna  130  of  FIG. 14 ) and be near-field coupled to arms  72  and  70  (or at least to arm  72 ). Through this near-field coupling arrangement, signals at terminal  80  of self-resonant element  74  can be passed to (or from) the rest of resonating element  68 , so that the behavior of the rest of resonating element  68  contributes to the performance of antenna  68 . 
   The electromagnetic interactions that underlie the principle of near-field coupling are illustrated in  FIG. 16 . In  FIG. 16 , conductors  140  and  142  are electromagnetically coupled through near field interactions. Conductors  140  and  142  are not electrically connected to each other, because gap  144  separates conductors  140  and  142 . As a result, direct current (DC) signals cannot pass from conductor  140  to conductor  142 . Through near-field coupling, however, signals on one of conductors  140  and  142  can be passed to the other. 
   Near field coupling can involve both electric-field coupling and magnetic-field coupling. As shown by arrows  146 , when the voltages on conductors  140  and  142  differ, an electric field E is established across gap  144 . As a result, when a voltage signal is generated on one conductor, a corresponding electric field spans gap  144  and induces currents in the other conductor. As shown by arrows  150 , when a current I flows in direction  148  in one of the conductors  140  and  142 , a magnetic field B is created. The magnetic field induces a similar current I in the other conductor. Signals can therefore be transmitted across gap  144  by near-field coupling, even though conductors  140  and  142  are not electrically connected by a DC path. 
   A near-field coupling mechanism is used in antenna  62  to couple signals into and out of resonating element  68 . Signals are applied to (and, in receive mode, are received from) feed terminal  80  and ground terminal  78  ( FIG. 4 ). Feed terminal  80  is connected to self-resonant element  74 . Self-resonant element  74  forms an antenna that resonates at a range of frequencies centered around a single peak, as described in connection with  FIGS. 14 and 15 . Through near-field coupling, the rest of resonating element  68  is coupled to self-resonant element  74  and positive terminal  80 , so that arms  70 ,  72 , and  74  each provide contributions to the overall performance of resonating element  68 . In particular, arm  72  can be near-field coupled to self-resonant element  74  by the relatively close proximity of element  74  and element  72  (e.g., a gap of about 1-3 mm between these elements). Although arm  70  can be located farther from element  74 , arm  70  may also be somewhat near-field coupled to element  74  and can be, in any event, electrically coupled to arm  72  by conductive portion  71 . The near-field coupling arrangement of antenna  62  may be referred to as a near-field-coupled feed arrangement, because the antenna&#39;s feed terminal is connected to near-field coupling element  74 . 
   The different resonating element portions of antenna  62  work together to provide broad frequency coverage. With one suitable arrangement antenna  62  can cover six communications bands of interest. The contributions of the different parts of antenna  62  to its overall frequency characteristic can be understood with reference to  FIGS. 15 ,  17 ,  18 , and  19 . 
   As described in connection with antenna  120  of  FIG. 11 , resonating element arm  72  and ground  66  of antenna  62  exhibit a response of the type shown in  FIG. 17 . As shown in  FIG. 17 , the antenna resonates (and therefore may be used for transmission and reception of radio-frequency signals) at fundamental frequency f 0  and at harmonic frequency 2f 0 . The contribution of arm  72  therefore allows antenna  62  to cover frequency bands at f 1 =f 0  and at f 3 =2f 0 , as shown in  FIG. 17 . 
   Arm  70  of antenna  62  can contribute resonance peaks at slightly higher frequency f 0 ′ and at slightly higher frequency 2f 0 ′, corresponding to respective communications bands frequencies f 2  and f 4 . The combined contributions of arms  70  and  72  are shown in the performance characteristic of  FIG. 18 . As shown in  FIG. 18 , when contributions from both arm  72  and arm  70  are taken into consideration, the antenna&#39;s response can include a first operative frequency range that covers communications bands centered around f 1  and f 2  and a second operative frequency range that covers communications bands centered around f 3  and f 4 . 
   Self-resonant antenna element  74  can make another contribution to the performance of antenna  62 . As shown in  FIG. 15  and as described in connection with  FIG. 14 , the contribution of element  74  is characterized by a single peak centered about a frequency f a . The size of self-resonant element  74  may be selected (as an example) so that the frequency f a  lies between two further communications bands of interest f 5  and f 6 . By including element  74  in resonating element  68  and antenna  62 , the overall performance of antenna  62  can be boosted in the vicinity of frequency f a . 
   An illustrative overall performance characteristic for antenna  62  is shown in  FIG. 19 . As shown in  FIG. 19 , antenna  62  operates in a first (lower) frequency range that covers bands f 1  and f 2  and in a second (higher) frequency range that covers communications bands f 3 , f 4 , f 5 , and f 6 . The contribution from element  74  boosts the frequency response of antenna  62  in the second frequency range around the frequency f a  and ensures that the second frequency range covers the communications bands centered at f 5  and f 6 . With one suitable arrangement, antenna  62  may be used to cover communications frequency bands, such as the cellular telephone bands at 850 MHz, 900 MHz, 1800 MHz, and 1900 MHz, data service bands, such as the 3G data communications band at 2170 MHz band (commonly referred to as UMTS or Universal Mobile Telecommunications System), the WiFi® (IEEE 802.11) band at 2.4 GHz, and the Bluetooth® band at 2.4 GHz. With this type of arrangement, f 1 =850 MHz, f 2 =900 MHz, f 3 =1800 MHz, f 4 =1900 MHz, f 5 =2170 MHz, and f 6 =2.4 GHz, for example. 
   One way to characterize the performance of broadband antenna  62  involves the use of a standing-wave-ratio plot. The standing-wave ratio (SWR) of an antenna is a measure of the antenna&#39;s ability to efficiently transmit radio waves. Standing wave ratios R of less than about three are generally acceptable. A graph plotting the measured standing-wave-ratio versus frequency characteristic for an illustrative broadband antenna of the type shown in  FIG. 4  is shown in  FIG. 20 . In the example of  FIG. 20 , the SWR value for the antenna is three or less in the vicinity of all bands of interest such as the 850 MHz, 900 MHz, 1800 MHz, and 1900 MHz cellular telephone bands, and the 2170 MHz and 2400 MHz data bands (in this example). 
   The performance of broadband antenna  62  has also been characterized by measuring its efficiency in several frequency ranges of interest. The graphs of  FIGS. 21 ,  22 , and  23  demonstrate how broadband antenna  62  has been measured to have good efficiency characteristics from 824-960 MHz ( FIG. 21 ), 1710-1990 MHz ( FIG. 22 ), and 2400-2485 MHz ( FIG. 23 ). Based on the SWR results of  FIG. 19 , antenna  62  is also expected to have good efficiency characteristics at 2170 MHz. 
   As shown in  FIG. 24 , antenna  62  can be formed in a configuration in which resonating element  68  is not surrounded with ground  66 . If desired, arms such as arms  70  and  72  and self-resonant element  74  may have different sizes and shapes. The arrangement of  FIG. 24  is merely illustrative. 
   As shown in  FIG. 25 , antenna  62  may be formed in a configuration that uses a parallel-fed self-resonant element  74 , where strip-shaped shorting conductive portion  75  is used to electrically connect element  74  to ground  66 . In this configuration, element  74  is electrically connected to ground  66  through conductor  75 , but due to the near-field coupling between element  74  and arm  72  and due to the connection of arms  70  and  72  through conductor  71 , arms  70  and  72  and element  74  serve as the antenna&#39;s resonating element. 
   If desired, antenna  62  may be formed using a three-dimensional arrangement. A cross-sectional view of antenna  62  in a three-dimensional configuration in handheld device  10  is shown in  FIG. 26 . As shown in  FIG. 26 , handheld electronic device  10  has a case  12 . Case  12  may be used to house electrical components  112 - 1  and  112 - 2  such as speakers, cameras, microphones, batteries, integrated circuits, keypads and other user control interfaces, connectors such as input-output jacks and power jacks, status indicators such as light-emitting diodes, displays such as liquid crystal displays, etc. 
   Case  12  may, as an example, be formed from metal or other conductive materials. Case  12  may also have a non-conductive portion such as cap  13 . Cap  13  may be formed from plastic or other suitable dielectric and may be located adjacent to resonating element  68  of antenna  62 . Ground  66  of antenna  62  may be formed from metal or other suitable conductors formed on one or both sides of circuit board  154  or other suitable mounting structures. Ground  66  may also be formed by metal or other suitable conductors that are used to encase the electrical components in device  10 . For example, some or all of components  112 - 1  may be encased in a conductive shielding layer  155  (e.g., copper RF shielding). Ground  66  may be formed at least partly using this conductive shielding as shown in  FIG. 26 . The conductive shielding may be electrically connected to conductive case  12  (e.g., using screws, brackets, and other connecting structures in device  10 ), which further extends ground  66 . 
   Connector  157  (e.g., a connector such as a mini UFL connector) or other suitable attachment structures may be used to connect coaxial cable  152  or other suitable radio-frequency signal path structures to components  66 . In the example of  FIG. 26 , connector  154  is shown schematically as being connected to components  112 - 1 . This is merely illustrative. Connector  154  may, for example, be connected to circuit board  154 , may be part of a transceiver module that makes up one of components  112 - 1 , or may be connected to electrical components in device  10  using any other suitable technique. 
   Coaxial cable center conductor  158  may be electrically connected to resonating element  68  using solder  160  (as an example). Outer conductive braid  161  of coaxial cable  152  may be soldered to ground  66  (e.g., metal shielding surrounding components  112 - 1 ) using solder  156 . Solder  160  may be used to connect conductor  158  to self-resonant element  74  at feed terminal  80  of  FIG. 4 . Solder  156  may be used to connect outer conductive portion  161  of cable  152  to ground  66  at ground terminal  78  of  FIG. 4 . 
   Resonating element  68  may be formed on a flexible substrate (e.g., a flexible polyimide-backed circuit substrate sometimes referred to as a flex circuit). A plastic support or other suitable structure  162  may be used to support the flex circuit from either side of the flex circuit. Ground extension portions such as portions  84 ,  86 , and  88  of  FIG. 4  may be electrically connected to ground  66  on circuit board  154  using solder, spring-loaded pins, or other suitable electrical connection structures  164 . 
   To ensure that antenna  62  works properly, it may be desirable to locate components that contain large amounts of conductor in components region  112 - 1  and to locate other components in components region  112 - 2 . For example, integrated circuits such as a transceiver integrated circuit, microprocessor, and memory, may be encased in conductive shielding. Due to the presence of the conductive shielding, which is shorted to ground  66 , these components may be best located in components region  112 - 1 , adjacent to metal case  12 . Other components may be located in region  112 - 2 . With one suitable arrangement, certain components (e.g., a microphone and speaker) are located in region  112 - 2 . If desired, there may be few or no components in components region  112 - 2 , so that resonating element  68  is surrounded by air. 
   Circuit board  154  and portions of ground element  66  that are formed from metal or other conductive materials located on one or both sides of circuit board  154  may be mounted to planar front face  22  of housing  12  and device  10  (as an example). To provide sufficient clearance between resonating element  68  and portions of ground  66  that are associated with components  112 - 2  and lie on circuit board  154  in region  166 , case  12  and support  162  may be constructed to ensure that there is at least 5-10 mm of vertical spacing between circuit board  154  and resonating element  68  along dimension  168 , which is perpendicular to the plane containing circuit board  154  and planar housing face  22 . 
   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: 20061106
Publication Date: 20100330
Grant Date: 20100330
Priority Date: 20061106
Inventors: HILL ROBERT J.
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q5/392", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/42", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q9/42", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q9/0421", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/38", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q5/392", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/38", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/0421", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 39232922