Patent Publication Number: US-7911387-B2

Title: Handheld electronic device antennas

Description:
BACKGROUND 
     This invention relates generally to wireless communications, and more particularly, to wireless communications circuitry for handheld electronic devices. 
     Handheld electronic devices are becoming increasingly popular. Examples of handheld devices include handheld computers, cellular telephones, media players, and hybrid devices that include the functionality of multiple devices of this type. 
     Due in part to their mobile nature, handheld electronic devices are often provided with wireless communications capabilities. Handheld electronic devices may use wireless communications to communicate with wireless base stations. For example, cellular telephones may communicate using cellular telephone bands at 850 MHz, 900 MHz, 1800 MHz, and 1900 MHz (e.g., the main Global System for Mobile Communications or GSM cellular telephone bands). Handheld electronic devices may also use other types of communications links. For example, handheld electronic devices may communicate using the WiFi® (IEEE 802.11) band at 2.4 GHz and the Bluetooth® band at 2.4 GHz. Communications are also possible in data service bands such as the 3G data communications band at 2170 MHz band (commonly referred to as UMTS or Universal Mobile Telecommunications System). 
     To satisfy consumer demand for small form factor wireless devices, manufacturers are continually striving to reduce the size of components that are used in these devices. For example, manufacturers have made attempts to miniaturize the antennas used in handheld electronic devices. 
     A typical antenna may be fabricated by patterning a metal layer on a circuit board substrate or may be formed from a sheet of thin metal using a foil stamping process. Many devices use planar inverted-F antennas (PIFAs). Planar inverted-F antennas are formed by locating a planar resonating element above a ground plane. These techniques can be used to produce antennas that fit within the tight confines of a compact handheld device. With conventional handheld electronic devices, however, design compromises are made to accommodate compact antennas. These design compromises may include, for example, compromises related to antenna height above the ground plane, antenna efficiency, and antenna bandwidth. Moreover, constraints are often placed on the amount of metal that can be used in a handheld device and on the location of metal parts. These constraints can adversely affect device operation and device appearance. 
     It would therefore be desirable to be able to provide improved handheld electronic devices and antennas for handheld electronic devices. 
     SUMMARY 
     In accordance with an embodiment of the present invention, a handheld electronic device with wireless communications circuitry is provided. The handheld electronic device may have cellular telephone, music player, or handheld computer functionality. The wireless communications circuitry may have one or more antennas. The antennas may be used to support wireless communications over data communications bands and cellular telephone communications bands. 
     The handheld electronic device may have a housing. The front face of the housing may have a display. The display may be a liquid crystal diode (LCD) display or other suitable display. A touch sensor may be integrated into the display to make the display touch sensitive. 
     A bezel may be used to attach the display to the housing. The bezel may surround the periphery of the front face of the housing and may hold the display against the housing. 
     The bezel and at least a portion of the housing may be formed from metal or other conductive materials. Electrical components, such as the display, printed circuit boards, integrated circuits, and a housing frame may be grounded together to form an antenna ground plane. 
     An antenna slot may be formed in the ground plane between the bezel and the conductive portion of the housing. The slot may have a rectangular shape or other suitable shapes. Components such as a dock connector and a flex circuit can be configured so that they overlap somewhat with the rectangular slot shape, thereby altering the inner perimeter of the slot. With one suitable arrangement, the dock connector and flex circuit are configured so that slot perimeter length increases due to the presence of the overlapping dock connector are balanced and substantially canceled by perimeter length decreases due to the overlapping flex circuit. The flex circuit may be used to route signals from the dock connector to processing circuitry on the handheld electronic device. 
     The handheld electronic device may have transceiver circuitry for handling wireless communications signals. With one illustrative arrangement, the handheld electronic device may have first and second radio-frequency transceivers and first and second corresponding antenna resonating elements. The first antenna resonating element may be used with the antenna ground plane to form a cellular telephone antenna. The second antenna resonating element may be used with the antenna ground plane to form a data band antenna (e.g., at 2.4 GHz). The antenna resonating elements may be located over the slot in the ground plane. 
     The antenna slot may have an associated resonant frequency peak. The perimeter of the slot may be adjusted so that the resonant frequency peak for the slot coincides with at least one communications band associated with the cellular telephone antenna. 
     Electrical components such as a menu button or other user interface control, a speaker module, and a microphone module, may be placed in an overlapping relationship with the antenna slot and one or more of the antenna resonating elements. To prevent interference between the antennas and these overlapping electrical components, the overlapping electrical components may be isolated using isolation elements. Inductors or resistors may be used for the isolation elements. 
     Radio-frequency signals may be routed between the transceiver circuits and the antennas using transmission lines such as coaxial cables. For example, in a handheld electronic device arrangement having two transceivers and two antennas, two coaxial cables may be used to route radio-frequency signals to and from the antennas. To ensure proper grounding of the coaxial cables and to prevent reflected signals from radiating out of the coaxial cables instead of the antennas, the coaxial cables may be electrically shorted to the conductive housing of the handheld electronic device and other portions of the antenna ground plane. 
     With one suitable arrangement, at least some segments of the coaxial cables have exposed outer ground connectors. Conductive fasteners may be attached to the exposed ground connector portions of the coaxial cables. For example, metal ferrules may be crimped to the coaxial cables at the exposed ground conductor locations along their lengths, thereby electrically shorting the metal ferrules to the coaxial cables. In turn, the metal ferrules or other conductive fasteners may be connected to the conductive housing and other portions of the antenna ground plane in the handheld electronic device. 
     A J-clip or other suitable conductive member may be used to structurally and electrically connect the metal ferrules to a metal frame in the device housing and other portions of the antenna ground plane. The conductive member may have bendable extensions and a base that is welded to the frame. The extensions on the conductive member may be crimped over the ferrules during assembly. In the event that the handheld electronic device needs to be reworked or recycled, the extensions may be bent open to release the coaxial cables. Releasably fastening the coaxial cable ground conductors to the antenna ground in this way may therefore facilitate both rework and recycling, while ensuring good antenna performance by properly grounding the coaxial cables. 
     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 in accordance with an embodiment of the present invention. 
         FIG. 2  is a schematic diagram of an illustrative handheld electronic device in accordance with an embodiment of the present invention. 
         FIG. 3  is a partly schematic top view of an illustrative handheld electronic device containing two radio-frequency transceivers that are coupled to two associated antenna resonating elements by respective transmission lines in accordance with an embodiment of the present invention. 
         FIG. 4  is a perspective view of an illustrative planar inverted-F antenna (PIFA) in accordance with an embodiment of the present invention. 
         FIG. 5  is a cross-sectional side view of an illustrative planar inverted-F antenna of the type shown in  FIG. 4  in accordance with an embodiment of the present invention. 
         FIG. 6  is an illustrative antenna performance graph for an antenna of the type shown in  FIGS. 4 and 5  in which standing-wave-ratio (SWR) values are plotted as a function of operating frequency in accordance with an embodiment of the present invention. 
         FIG. 7  is a perspective view of an illustrative planar inverted-F antenna in which a portion of the antenna&#39;s ground plane underneath the antenna&#39;s resonating element has been removed to form a slot in accordance with an embodiment of the present invention. 
         FIG. 8  is a top view of an illustrative slot antenna in accordance with an embodiment of the present invention. 
         FIG. 9  is an illustrative antenna performance graph for an antenna of the type shown in  FIG. 8  in which standing-wave-ratio (SWR) values are plotted as a function of operating frequency in accordance with an embodiment of the present invention. 
         FIG. 10  is a perspective view of an illustrative hybrid PIFA/slot antenna formed by combining a planar inverted-F antenna with a slot antenna in which the antenna is being fed by two coaxial cable feeds in accordance with an embodiment of the present invention. 
         FIG. 11  is an illustrative wireless coverage graph in which antenna standing-wave-ratio (SWR) values are plotted as a function of operating frequency for a handheld device that contains a hybrid PIFA/slot antenna and a strip antenna in accordance with an embodiment of the present invention. 
         FIG. 12  is a perspective view of an illustrative handheld electronic device antenna arrangement in which a first of two handheld electronic device antennas has an associated isolation element that serves to reduce interference with from a second of the two handheld electronic device antennas in accordance with an embodiment of the present invention. 
         FIG. 13  is a cross-sectional view of an illustrative handheld electronic device in accordance with an embodiment of the present invention. 
         FIG. 14  is a somewhat simplified interior perspective view of an illustrative handheld electronic device with a conductive bezel in accordance with an embodiment of the present invention. 
         FIG. 15  is an exploded top perspective view of an illustrative handheld electronic device in accordance with an embodiment of the present invention. 
         FIG. 16  is an exploded bottom perspective view of an illustrative handheld electronic device in accordance with an embodiment of the present invention. 
         FIG. 17  is an exploded perspective bottom interior view of an illustrative handheld electronic device showing how a handheld electronic device may have coaxial cable transmission lines and flex circuit antenna resonating elements in accordance with an embodiment of the present invention. 
         FIG. 18  is a perspective interior view of an illustrative rear housing portion in accordance with an embodiment of the present invention. 
         FIG. 19  is a top view of an illustrative handheld electronic device in which a cosmetic plastic cap has been removed to expose antenna resonating elements in accordance with an embodiment of the present invention. 
         FIG. 20  is a perspective view of a portion of an illustrative antenna coaxial cable to which a conductive fastener such as a ferule has been attached in accordance with an embodiment of the present invention. 
         FIG. 21  is a perspective interior view of a portion of an illustrative handheld electronic device showing how a data channel antenna may be connected to a coaxial cable transmission line in accordance with an embodiment of the present invention. 
         FIG. 22  is a perspective view of a portion of an illustrative handheld electronic device in which two antenna coaxial cables have been routed together along the edge of the device in accordance with an embodiment of the present invention. 
         FIG. 23  is a perspective view of an interior end portion of an illustrative handheld electronic device showing how a coaxial cable antenna transmission line may be connected to an antenna in accordance with an embodiment of the present invention. 
         FIG. 24  is a perspective view of a portion of the interior of an illustrative handheld electronic device showing how a flex circuit may be used to route connector signals around the edge of the handheld electronic device and showing the location of components such as a microphone, menu button, and speaker module in accordance with an embodiment of the present invention. 
         FIG. 25  is a partially sectional perspective view of a portion of the interior of an illustrative handheld electronic device showing the location of an antenna grounding bracket that may be used to make contact between antenna flex circuit traces and a bezel on the handheld electronic device in accordance with an embodiment of the present invention. 
         FIG. 26  is a perspective view of an end portion of an illustrative handheld electronic device showing the location of components such as a dock connector and menu button in the handheld electronic device in accordance with an embodiment of the present invention. 
         FIG. 27  is a perspective view of a portion of the interior of an illustrative handheld electronic device showing an illustrative flex circuit antenna configuration in accordance with an embodiment of the present invention. 
         FIGS. 28 and 29  are perspective bottom views of the interior of an illustrative handheld electronic device in accordance with an embodiment of the present invention. 
         FIG. 30  is a rear view of an upper interior portion of an illustrative handheld electronic device in accordance with an embodiment of the present invention. 
         FIG. 31  is a cross-sectional view of an interior portion of an illustrative handheld electronic device showing how a spring may be used to help electrically connect a housing frame to a housing in accordance with an embodiment of the present invention. 
         FIG. 32  is a rear view of a middle interior portion of an illustrative handheld electronic device in accordance with an embodiment of the present invention. 
         FIG. 33  is a perspective view of an end portion of an illustrative handheld electronic device in accordance with an embodiment of the present invention. 
         FIG. 34  is a cross-sectional view of an interior portion of an illustrative handheld electronic device in accordance with an embodiment of the present invention. 
         FIG. 35  is a partially cross-sectional perspective view of a middle interior portion of an illustrative handheld electronic device in accordance with an embodiment of the present invention. 
         FIG. 36  is a cross-sectional view of a portion of a housing and a bezel in an illustrative handheld electronic device in accordance with an embodiment of the present invention. 
         FIG. 37  is a top view of an antenna slot with overlapping electrical components in an illustrative handheld electronic device in accordance with an embodiment of the present invention. 
         FIG. 38  is circuit diagram showing how isolation elements may be used to interconnect a menu button with control circuitry in an illustrative handheld electronic device in accordance with an embodiment of the present invention. 
         FIG. 39  is a top view of an illustrative handheld electronic device showing overlap between an electronic component and antenna resonating elements in accordance with an embodiment of the present invention. 
         FIG. 40  is a perspective view of a section of coaxial cable with exposed segments and insulated segments in accordance with an embodiment of the present invention. 
         FIG. 41  is an antenna performance graph showing how the resonance peak of a handheld electronic device antenna having a ground plane with a slot can be adjusted by positioning electronic components to change the inner perimeter of the slot in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention relates generally to wireless communications, and more particularly, to wireless electronic devices and antennas for wireless electronic devices. 
     The wireless electronic devices may be portable electronic devices such as laptop computers or small portable computers of the type that are sometimes referred to as ultraportables. 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, which is sometimes described herein as an example, the portable electronic devices are handheld electronic devices. 
     The 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 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. 
     An illustrative handheld electronic device in accordance with an embodiment of the present invention is shown in  FIG. 1 . Device  10  may be any suitable portable or handheld electronic device. 
     Device  10  may have housing  12 . Device  10  may include one or more antennas for handling wireless communications. Embodiments of device  10  that contain one antenna and embodiments of device  10  that contain two antennas are sometimes described herein as examples. 
     Device  10  may handle communications over one or more communications bands. For example, in a device  10  with two antennas, a first of the two antennas may be used to handle cellular telephone communications in one or more frequency bands, whereas a second of the two antennas may be used to handle data communications in a separate communications band. With one suitable arrangement, which is sometimes described herein as an example, the second antenna is configured to handle data communications in a communications band centered at 2.4 GHz (e.g., WiFi and/or Bluetooth frequencies). In configurations with multiple antennas, the antennas may be designed to reduce interference so as to allow the two antennas to operate in relatively close proximity to each other. 
     Housing  12 , which is sometimes referred to as a case, may be formed of any suitable materials including, plastic, glass, ceramics, metal, or other suitable materials, or a combination of these materials. In some situations, housing  12  or portions of housing  12  may be formed from a dielectric or other low-conductivity material, so that the operation of conductive antenna elements that are located in proximity to housing  12  is not disrupted. Housing  12  or portions of housing  12  may also be formed from conductive materials such as metal. An illustrative housing material that may be used is anodized aluminum. Aluminum is relatively light in weight and, when anodized, has an attractive insulating and scratch-resistant surface. If desired, other metals can be used for the housing of device  10 , such as stainless steel, magnesium, titanium, alloys of these metals and other metals, etc. In scenarios in which housing  12  is formed from metal elements, one or more of the metal elements may be used as part of the antennas in device  10 . For example, metal portions of housing  12  may be shorted to an internal ground plane in device  10  to create a larger ground plane element for that device  10 . To facilitate electrical contact between an anodized aluminum housing and other metal components in device  10 , portions of the anodized surface layer of the anodized aluminum housing may be selectively removed during the manufacturing process (e.g., by laser etching). 
     Housing  12  may have a bezel  14 . The bezel  14  may be formed from a conductive material. The conductive material may be a metal (e.g., an elemental metal or an alloy) or other suitable conductive materials. With one suitable arrangement, which is sometimes described herein as an example, bezel  14  may be formed from stainless steel. Stainless steel can be manufactured so that it has an attractive shiny appearance, is structurally strong, and does not corrode easily. If desired, other structures may be used to form bezel  14 . For example, bezel  14  may be formed from plastic that is coated with a shiny coating of metal or other suitable substances. Arrangements in which bezel  14  is formed from a conductive metal such as stainless steel are often described herein as an example. 
     Bezel  14  may serve to hold a display or other device with a planar surface in place on device  10 . As shown in  FIG. 1 , for example, bezel  14  may be used to hold display  16  in place by attaching display  16  to housing  12 . Device  10  may have front and rear planar surfaces. In the example of  FIG. 1 , display  16  is shown as being formed as part of the planar front surface of device  10 . The periphery of the front surface may be surrounded by a bezel, such as bezel  14 . If desired, the periphery of the rear surface may be surrounded by a bezel (e.g., in a device with both front and rear displays). 
     Display  16  may be a liquid crystal diode (LCD) display, an organic light emitting diode (OLED) display, or any other suitable display. The outermost surface of display  16  may be formed from one or more plastic or glass layers. If desired, touch screen functionality may be integrated into display  16  or may be provided using a separate touch pad device. An advantage of integrating a touch screen into display  16  to make display  16  touch sensitive is that this type of arrangement can save space and reduce visual clutter. 
     In a typical arrangement, bezel  14  may have prongs that are used to secure bezel  14  to housing  12  and that are used to electrically connect bezel  14  to housing  12  and other conductive elements in device  10 . The housing and other conductive elements form a ground plane for the antenna(s) in the handheld electronic device. A gasket (e.g., an o-ring formed from silicone or other compliant material, a polyester film gasket, etc.) may be placed between the underside of bezel  14  and the outermost surface of display  16 . The gasket may help to relieve pressure from localized pressure points that might otherwise place stress on the glass or plastic cover of display  16 . The gasket may also help to visually hide portions of the interior of device  10  and may help to prevent debris from entering device  10 . 
     In addition to serving as a retaining structure for display  16 , bezel  14  may serve as a rigid frame for device  10 . In this capacity, bezel  14  may enhance the structural integrity of device  10 . For example, bezel  14  may make device  10  more rigid along its length than would be possible if no bezel were used. Bezel  14  may also be used to improve the appearance of device  10 . In configurations such as the one shown in  FIG. 1  in which bezel  14  is formed around the periphery of a surface of device  10  (e.g., the periphery of the front face of device  10 ), bezel  14  may help to prevent damage to display  16  (e.g., by shielding display  16  from impact in the event that device  10  is dropped, etc.). 
     Display screen  16  (e.g., a touch screen) is merely one example of an input-output device that may be used with handheld electronic device  10 . If desired, handheld electronic device  10  may have other input-output devices. For example, handheld electronic device  10  may have user input control devices such as button  19 , and input-output components such as port  20  and one or more input-output jacks (e.g., for audio and/or video). Button  19  may be, for example, a menu button. Port  20  may contain a 30-pin data connector (as an example). Openings  24  and  22  may, if desired, form microphone and speaker ports. 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. In the example of  FIG. 1 , display screen  16  is shown as being mounted on the front face of handheld electronic device  10 , but display screen  16  may, if desired, 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. Bezels such as bezel  14  of  FIG. 1  may be used to mount display  16  or any other device with a planar surface to housing  12  in any of these locations. 
     A user of handheld device  10  may supply input commands using user input interface devices such as button  19  and touch screen  16 . Suitable user input interface devices for handheld electronic device  10  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 microphone for supplying voice commands, or any other suitable interface for controlling device  10 . Although shown schematically as being formed on the top face of handheld electronic device  10  in the example of  FIG. 1 , buttons such as button  19  and other user input interface devices may generally be formed on any suitable portion of handheld electronic device  10 . For example, a button such as button  19  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 port  20 . Port  20 , which may sometimes be referred to as a dock connector, 30-pin data port connector, input-output port, or bus connector, may be used as an input-output port (e.g., when connecting device  10  to a mating dock connected to a computer or other electronic device. Device  10  may also have audio and video jacks 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, a subscriber identity module (SIM) card port to authorize cellular telephone service, a memory card slot, etc. The functions of some or all of these devices and the internal circuitry of handheld electronic device  10  can be controlled using input interface devices such as touch screen display  16 . 
     Components such as display  16  and other user input interface devices may cover most of the available surface area on the front face of device  10  (as shown in the example of  FIG. 1 ) or may occupy only a small portion of the front face of device  10 . Because electronic components such as display  16  often contain large amounts of metal (e.g., 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 antennas of handheld electronic device  10  to function properly without being disrupted by the electronic components. 
     With one suitable arrangement, the antennas of device  10  are located in the lower end  18  of device  10 , in the proximity of port  20 . An advantage of locating antennas in the lower portion of housing  12  and device  10  is that this places the antennas away from the user&#39;s head when the device  10  is held to the head (e.g., when talking into a microphone and listening to a speaker in the handheld device as with a cellular telephone). This reduces the amount of radio-frequency radiation that is emitted in the vicinity of the user and minimizes proximity effects. 
     A schematic diagram of an embodiment of an illustrative handheld electronic device 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 other 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. With one suitable arrangement, processing circuitry  36  and storage  34  are 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. Processing circuitry  36  and storage  34  may be used in implementing suitable communications protocols. Communications protocols that may be implemented using processing circuitry  36  and storage  34  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, etc.). 
     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 , button  19 , microphone port  24 , speaker port  22 , and dock connector port  20  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 or other 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, 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). 
     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 any suitable computer. With one suitable arrangement, computing equipment  48  is a computer that has an associated wireless access point (router) or an internal or external wireless card that establishes a wireless connection with device  10 . The computer may be a server (e.g., an internet server), a local area network computer with or without internet access, a user&#39;s own personal computer, a peer device (e.g., another handheld electronic device  10 ), or any other suitable computing equipment. 
     The antennas and wireless communications devices of device  10  may support communications over any suitable wireless communications bands. For example, 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) bands at 2.4 GHz and 5.0 GHz, the Bluetooth® band at 2.4 GHz, and the global positioning system (GPS) band at 1550 MHz. These are merely illustrative communications bands over which devices  44  may operate. Additional local and remote communications 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. Device  10  may use one antenna, two antennas, or more than two antennas to provide wireless coverage over all communications bands of interest. 
     A top view of an illustrative device  10  in accordance with an embodiment of the present invention is shown in  FIG. 3 . As shown in  FIG. 3 , transceiver circuitry such as transceiver  52 A and transceiver  52 B may be interconnected with antenna resonating elements  54 - 1 A and  54 - 1 B over respective transmission lines  56 A and  56 B. In the example of  FIG. 3 , there are two transceivers, two corresponding transmission lines, and two corresponding antenna resonating elements. This is merely illustrative. For example, device  10  may have one transceiver, one corresponding transmission line, and one corresponding antenna resonating element or device  10  may have more than two transceivers, transmission lines, and antenna resonating elements. 
     Portions of device  10  may form a ground for the antennas formed by resonating elements  54 - 1 A and  54 - 1 B. The antenna ground, which is sometimes referred to as the antenna ground plane or antenna ground plane element, may be formed of conductive device structures such as printed circuit boards, transceiver shielding cans, integrated circuits, batteries, displays, buttons, screws, clamps, brackets, flex circuits, and portions of housing  12 . Components  52  of this type are shown schematically in  FIG. 3  as transceivers  52 A and  52 B and as battery and other components  52 C. With one suitable arrangement, which is sometimes described herein as an example, such grounded conductive structures are located in region  170 , above dotted line  23  in  FIG. 3 . 
     Bezel  14  may surround device  10  and may be electrically connected to antenna ground (e.g., by shorting bezel  14  to the conductive structures in region  170  of device  10 ). When bezel  14  is connected to the ground structures, bezel  14  forms part of the ground for the antenna(s) of device  10  (i.e., bezel  14  becomes part of antenna ground plane  54 - 2 ). 
     Ground plane  54 - 2  may have a substantially rectangular shape (i.e., the lateral dimensions of ground plane  54 - 2  may match those of device  10  and the periphery of ground plane  54 - 2  may be substantially rectangular) and may contain an opening beneath resonating elements  54 - 1 A and  54 - 1 B. The opening in ground plane  54 - 2  is sometimes referred to as a hole or slot and is generally filed with air and other dielectrics and components that do not significantly affect radio-frequency antenna signals. The opening may be of any suitable shape. For example, the opening may be rectangular in shape. In this type of scenario, bezel  14  may define right, left, and lower sides of the opening (in the orientation of  FIG. 3 ), whereas the conductive device structures above line  23  (e.g., printed circuit board, conductive housing surfaces, conductive display components, and other conductive electrical components) may form a top side of the opening (in the orientation of  FIG. 3 ). In some embodiments of device  10 , one or more conductive structures such as dock connector  20  ( FIG. 1 ) may overlap at least partly with the otherwise rectangular opening defined by the ground structures above line  23  and bezel  14 . In this type of arrangement, the opening in ground plane  54 - 2  may have a non-rectangular shape. Non-rectangular shapes for the opening may include, for example, polygons, squares, ovals, shapes with both flat and curved sides, etc. 
     When operated in conjunction with antenna ground  54 - 2 , antenna resonating elements such as resonating elements  54 - 1 A and  54 - 1 B form antennas  54  for device  10 . In the example of  FIG. 3 , there are two antennas in device  10 , one of which is associated with antenna resonating element  54 - 1 A and one of which is associated with antenna resonating element  54 - 1 B. This is, however, merely illustrative. There may, in general, be one antenna, two antennas, or three or more antennas in device  10 . 
     Antenna resonating elements in device  10  may be formed in any suitable shape. With one illustrative arrangement, one of antennas  54  (i.e., the antenna formed from resonating element  54 - 1 A) is based at least partly on a planar inverted-F antenna (PIFA) structure and the other antenna (i.e., the antenna formed from resonating element  54 - 1 B) is based on a planar strip configuration. Although this embodiment may be described herein as an example, any other suitable shapes may be used for resonating elements  54 - 1 A and  54 - 1 B if desired. 
     To permit antennas  54  to function properly, part of the housing of device  10  (i.e., portions in region  18 ) may be formed from plastic or another suitable dielectric material. With one suitable arrangement, which is described herein as an example, antenna resonating elements  54 - 1 A and  54 - 1 B may be formed from conductive copper traces on a flex circuit. The flex circuit may be mounted to a plastic supporting piece that is sometimes referred to as an antenna cap or antenna support. A plastic cover, which is sometimes referred to as a cosmetic cap or housing cap, may be used to enclose the antennas. The cosmetic cap may form a portion of the housing of device  10  in region  18 . The cosmetic cap may be formed from a plastic based on acrylonitrile-butadiene-styrene copolymers (sometimes referred to as ABS plastic). If desired, plastic portions of the housing of device  10  may be formed from low dielectric constant materials. An example of this type of plastic is the low dielectric constant plastic that is sold under the trade name IXEF® by Solvay Advanced Polymers, L.L.C. of Alpharetta, Ga. This plastic, which is a polyarylamide, has a satisfactory structural strength for forming parts of the housing of device  10 . 
     Components such as components  52  may be mounted on one or more circuit boards in device  10 . Typical components  52  include integrated circuits, LCD screens, and user input interface buttons. Device  10  also typically includes a battery such as a lithium-ion battery, which may be mounted along the rear face of housing  12  (as an example). One or more transceiver circuits such as transceiver circuits  52 A and  52 B may be mounted to one or more circuit boards in device  10 . With one suitable arrangement, two printed circuit boards may be stacked on top of each other in the housing of device  10 . In a configuration for device  10  in which there are two antenna resonating elements and two transceivers, each transceiver may be used to transmit radio-frequency signals through a respective one of two respective antenna resonating elements and may be used to receive radio-frequency signals through a respective one of two antenna resonating elements. A common ground  54 - 2  may be used with each of the two antenna resonating elements. 
     With one illustrative arrangement, transceiver  52 A may be used to transmit and receive cellular telephone radio-frequency signals and transceiver  52 B may be used to transmit signals in a communications band 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) bands at 2.4 GHz and 5.0 GHz, the Bluetooth® band at 2.4 GHz, or the global positioning system (GPS) band at 1550 MHz. 
     The circuit board(s) in device  10  may be formed from any suitable materials. With one illustrative arrangement, the circuit board or boards of device  10  may be provided using multilayer printed circuit board material. At least one of the layers may have large planar regions of conductor that form part of ground plane  54 - 2 . In a typical scenario, ground plane  54 - 2  is a rectangle that conforms to the generally rectangular shape of housing  12  and device  10  and matches the rectangular lateral dimensions of housing  12 . Circuit boards in ground plane  54 - 2  may, if desired, be electrically connected to conductive housing portions using shorting brackets, springs, screws, and other conductive structures. 
     Suitable circuit board materials for a multilayer printed circuit board in device  10  include 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. Circuit boards fabricated from materials such as FR-4 are commonly available, are not cost-prohibitive, and can be fabricated with multiple layers of metal (e.g., four layers). So-called flex circuits, which are formed using flexible circuit board materials such as polyimide, may also be used in device  10 . For example, flex circuits may be used to form the antenna resonating elements for antenna(s)  54 . In a typical flex circuit, antenna resonating elements may be formed from copper traces (e.g., on one side of the flex circuit substrate). 
     In the illustrative configuration of  FIG. 3 , ground plane element  54 - 2  and antenna resonating element  54 - 1 A may form a first antenna for device  10 . Ground plane element  54 - 2  and antenna resonating element  54 - 1 B may form a second antenna for device  10 . These two antennas form a multiband antenna having multiple resonating elements. If desired, other antenna structures can be provided. For example, additional resonating elements may be used to provide additional gain for an overlapping frequency band of interest (i.e., a band at which one of these antennas  54  is operating) or may be used to provide coverage in a different frequency band of interest (i.e., a band outside of the range of antennas  54 ). Bezel  14  is typically connected to antenna ground to form part of the ground  54 - 2  and thereby serve as a portion of antenna  54 . 
     Any suitable conductive materials may be used to form ground plane element  54 - 2  and resonating elements such as resonating element  54 - 1 A and  54 - 1 B. Examples of suitable conductive antenna materials include metals, such as copper, brass, silver, gold, and stainless steel (e.g., for bezel  14 ). Conductors other than metals may also be used, if desired. The planar conductive elements in antennas  54  are typically thin (e.g., about 0.2 mm). 
     Transceiver circuits  52 A and  52 B (i.e., transceiver circuitry  44  of  FIG. 2 ) may be provided in the form of one or more integrated circuits and associated discrete components (e.g., filtering components). These transceiver circuits may include one or more transmitter integrated circuits, one or more receiver integrated circuits, switching circuitry, amplifiers, etc. Transceiver circuits  52 A and  52 B may operate simultaneously (e.g., one can transmit while the other receives, both can transmit at the same time, or both can receive simultaneously). 
     Each transceiver may have an associated coaxial cable or other transmission line over which transmitted and received radio frequency signals are conveyed. As shown in the example of  FIG. 3 , transmission line  56 A (e.g., a coaxial cable) may be used to interconnect transceiver  52 A and antenna resonating element  54 - 1 A and transmission line  56 B (e.g., a coaxial cable) may be used to interconnect transceiver  52 B and antenna resonating element  54 - 1 B. With this type of configuration, transceiver  52 B may handle WiFi transmissions over an antenna formed from resonating element  54 - 1 B and ground plane  54 - 2 , while transceiver  52 A may handle cellular telephone transmission over an antenna formed from resonating element  54 - 1 A and ground plane  54 - 2 . 
     An illustrative planar inverted-F antenna (PIFA) structure is shown in  FIG. 4 . As shown in  FIG. 4 , PIFA structure  54  may have a ground plane portion  54 - 2  and a planar resonating element portion  54 - 1 A. Antennas are fed using positive signals and ground signals. The portion of an antenna to which the positive signal is provided is sometimes referred to as the antenna&#39;s positive terminal or feed terminal. This terminal is also sometimes referred to as the signal terminal or the center-conductor terminal of the antenna. The portion of an antenna to which the ground signal is provided may be referred to as the antenna&#39;s ground, the antenna&#39;s ground terminal, the antenna&#39;s ground plane, etc. In antenna  54  of  FIG. 4 , feed conductor  58  is used to route positive antenna signals from signal terminal  60  into antenna resonating element  54 - 1 A. Ground terminal  62  is shorted to ground plane  54 - 2 , which forms the antenna&#39;s ground. 
     The dimensions of the ground plane in a PIFA antenna such as antenna  54  of  FIG. 4  are generally sized to conform to the maximum size allowed by housing  12  of device  10 . Antenna ground plane  54 - 2  may be rectangular in shape having width W in lateral dimension  68  and length L in lateral dimension  66 . The length of antenna  54  in dimension  66  affects its frequency of operation. Dimensions  68  and  66  are sometimes referred to as horizontal dimensions. Resonating element  54 - 1 A is typically spaced several millimeters above ground plane  54 - 2  along vertical dimension  64 . The size of antenna  54  in dimension  64  is sometimes referred to as height H of antenna  54 . 
     A cross-sectional view of PIFA antenna  54  of  FIG. 4  is shown in  FIG. 5 . As shown in  FIG. 5 , radio-frequency signals may be fed to antenna  54  (when transmitting) and may be received from antenna  54  (when receiving) using signal terminal  60  and ground terminal  62 . In a typical arrangement, a coaxial cable or other transmission line has its center conductor electrically connected to point  60  and its ground conductor electrically connected to point  62 . 
     A graph of the expected performance of an antenna of the type represented by illustrative antenna  54  of  FIGS. 4 and 5  is shown in  FIG. 6 . Expected standing wave ratio (SWR) values are plotted as a function of frequency. The performance of antenna  54  of  FIGS. 4 and 5  is given by solid line  63 . As shown, there is a reduced SWR value at frequency f 1 , indicating that the antenna performs well in the frequency band centered at frequency f 1 . PIFA antenna  54  also operates at harmonic frequencies such as frequency f 2 . Frequency f 2  represents the second harmonic of PIFA antenna  54  (i.e., f 2 =2f 1 ). The dimensions of antenna  54  may be selected so that frequencies f 1  and f 2  are aligned with communication bands of interest. The frequency f 1  (and harmonic frequency 2f 1 ) are related to the length L of antenna  54  in dimension  66  (L is approximately equal to one quarter of a wavelength at frequency f 1 ). 
     In some configurations, the height H of antenna  54  of  FIGS. 4 and 5  in dimension  64  may be limited by the amount of near-field coupling between resonating element  54 - 1 A and ground plane  54 - 2 . For a specified antenna bandwidth and gain, it may not be possible to reduce the height H without adversely affecting performance. All other variables being equal, reducing height H will generally cause the bandwidth and gain of antenna  54  to be reduced. 
     As shown in  FIG. 7 , the minimum vertical dimension of the PIFA antenna can be reduced while still satisfying minimum bandwidth and gain constraints by introducing a dielectric region  70  in the form of an opening (slot) under antenna resonating element  54 - 1 A. Slot  70  may be filled with electrical parts with radio-frequency isolation, air, plastic, or other suitable dielectric and represents a cut-away or removed portion of ground plane  54 - 2 . With one suitable arrangement, which is shown in  FIG. 7 , the removed region  70  forms a rectangular slot. Slots of other shapes (oval, meandering, curved sides, straight sides, etc.) may also be formed. 
     The slot in ground plane  54 - 2  may be any suitable size. For example, the slot may be slightly smaller than the outermost rectangular outline of resonating elements  54 - 1 A and  54 - 2  as viewed from the top view orientation of  FIG. 3 . Typical resonating element lateral dimensions are on the order of 0.5 cm to 10 cm. 
     The presence of slot  70  reduces near-field electromagnetic coupling between resonating element  54 - 1 A and ground plane  54 - 2  and allows height H in vertical dimension  64  to be made smaller than would otherwise be possible while satisfying a given set of bandwidth and gain constraints. For example, height H may be in the range of 1-5 mm, may be in the range of 2-5 mm, may be in the range of 2-4 mm, may be in the range of 1-3 mm, may be in the range of 1-4 mm, may be in the range of 1-10 mm, may be lower than 10 mm, may be lower than 4 mm, may be lower than 3 mm, may be lower than 2 mm, or may be in any other suitable range of vertical displacements above ground plane element  54 - 2 . 
     If desired, the portion of ground plane  54 - 2  that contains slot  70  may be used to form a slot antenna. The slot antenna structure may be used alone to form an antenna for device  10  or the slot antenna structure may be used in conjunction with one or more resonating elements to form a hybrid antenna  54 . For example, one or more PIFA resonating elements may be used with the slot antenna structure to form a hybrid antenna. By operating antenna  54  so that it exhibits both PIFA operating characteristics and slot antenna operating characteristics, antenna performance can be improved. 
     A top view of an illustrative slot antenna is shown in  FIG. 8 . Antenna  72  of  FIG. 8  is typically thin in the dimension into the page (i.e., antenna  72  is planar with its plane lying in the page). Slot  70  may be formed in the center of antenna conductor  76 . A coaxial cable such as cable  56 A or other transmission line path may be used to feed antenna  72 . In the example of  FIG. 8 , antenna  72  is fed so that center conductor  82  of coaxial cable  56 A is connected to signal terminal  80  (i.e., the positive or feed terminal of antenna  72 ) and the outer braid of coaxial cable  56 A, which forms the ground conductor for cable  56 A, is connected to ground terminal  78 . 
     When antenna  72  is fed using the arrangement of  FIG. 8 , the antenna&#39;s performance is given by the graph of  FIG. 9 . As shown in  FIG. 9 , antenna  72  operates in a frequency band that is centered about center frequency f 2 . The center frequency f 2  is determined by the dimensions of slot  70 . Slot  70  has an inner perimeter P that is equal to two times dimension X plus two times dimension Y (i.e., P=2X+2Y). At center frequency f 2 , perimeter P is equal to one wavelength. 
     Because the center frequency f 2  can be tuned by proper selection of perimeter P, the slot antenna of  FIG. 8  can be configured so that frequency f 2  of the graph in  FIG. 9  coincides with frequency f 2  of the graph in  FIG. 6 . In an antenna design of this type in which slot  70  is combined with a PIFA structure, the presence of slot  70  increases the gain of the antenna at frequency f 2 . In the vicinity of frequency f 2 , the increase in performance from using slot  70  results in the antenna performance plot given by dotted line  79  in  FIG. 6 . 
     If desired, the value of perimeter P may be selected to resonate at a frequency that is different from frequency f 2  (i.e., out-of-band). In this scenario, the presence of slot  70  does not increase the performance of the antenna at resonant frequency f 2 . Nevertheless, the removal of the conductive material from the region of slot  70  reduces near-field electromagnetic coupling between resonating elements such as resonating element  54 - 1 A and ground plane  54 - 2  and allows height H in vertical dimension  64  to be made smaller than would otherwise be possible while satisfying a given set of bandwidth and gain constraints. 
     The position of terminals  80  and  78  may be selected for impedance matching. If desired, terminals such as terminals  84  and  86 , which extend around one of the corners of slot  70  may be used to feed antenna  72 . In this situation, the distance between terminals  84  and  86  may be chosen to properly adjust the impedance of antenna  72 . In the illustrative arrangement of  FIG. 8 , terminals  84  and  86  are shown as being respectively configured as a slot antenna ground terminal and a slot antenna signal terminal, as an example. If desired, terminal  84  could be used as a ground terminal and terminal  86  could be used as a signal terminal. Slot  70  is typically air-filled, but may, in general, be filled with any suitable dielectric. 
     By using slot  70  in combination with a PIFA-type resonating element such as resonating element  54 - 1 A, a hybrid PIFA/slot antenna is formed (sometimes referred to herein as a hybrid antenna). Handheld electronic device  10  may, if desired, have a PIFA/slot hybrid antenna of this type (e.g., for cellular telephone communications) and a strip antenna (e.g., for WiFi/Bluetooth communications). 
     An illustrative configuration in which the hybrid PIFA/slot antenna formed by resonating element  54 - 1 A, slot  70 , and ground plane  54 - 2  is fed using two coaxial cables (or other transmission lines) is shown in  FIG. 10 . When the antenna is fed as shown in  FIG. 10 , both the PIFA and slot antenna portions of the antenna are active. As a result, antenna  54  of  FIG. 10  operates in a hybrid PIFA/slot mode. Coaxial cables  56 A- 1  and  56 A- 2  have inner conductors  82 - 1  and  82 - 2 , respectively. Coaxial cables  56 A- 1  and  56 A- 2  also each have a conductive outer braid ground conductor. The outer braid conductor of coaxial cable  56 A- 1  is electrically shorted to ground plane  54 - 2  at ground terminal  88 . The ground portion of cable  56 A- 2  is shorted to ground plane  54 - 2  at ground terminal  92 . The signal connections from coaxial cables  56 A- 1  and  56 A- 2  are made at signal terminals  90  and  94 , respectively. 
     With the arrangement of  FIG. 10 , two separate sets of antenna terminals are used. Coaxial cable  56 A- 1  feeds the PIFA portion of the hybrid PIFA/slot antenna using ground terminal  88  and signal terminal  90  and coaxial cable  56 A- 2  feeds the slot antenna portion of the hybrid PIFA/slot antenna using ground terminal  92  and signal terminal  94 . Each set of antenna terminals therefore operates as a separate feed for the hybrid PIFA/slot antenna. Signal terminal  90  and ground terminal  88  serve as antenna terminals for the PIFA portion of the antenna, whereas signal terminal  94  and ground terminal  92  serve as antenna feed points for the slot portion of antenna  54 . These two separate antenna feeds allow the antenna to function simultaneously using both its PIFA and its slot characteristics. If desired, the orientation of the feeds can be changed. For example, coaxial cable  56 A- 2  may be connected to slot  70  using point  94  as a ground terminal and point  92  as a signal terminal or using ground and signal terminals located at other points along the periphery of slot  70 . 
     When multiple transmission lines such as transmission lines  56 A- 1  and  56 A- 2  are used for the hybrid PIFA/slot antenna, each transmission line may be associated with a respective transceiver circuit (e.g., two corresponding transceiver circuits such as transceiver circuit  52 A of  FIG. 3 ). 
     In operation in handheld device  10 , a hybrid PIFA/slot antenna formed from resonating element  54 - 1 A of  FIG. 3  and a corresponding slot that is located beneath element  54 - 1 A in ground plane  54 - 2  can be used to cover the GSM cellular telephone bands at 850 and 900 MHz and at 1800 and 1900 MHz (or other suitable frequency bands), whereas a strip antenna (or other suitable antenna structure) can be used to cover an additional band centered at frequency f n  (or another suitable frequency band or bands). By adjusting the size of the strip antenna or other antenna structure formed from resonating element  54 - 1 B, the frequency f n  may be controlled so that it coincides with any suitable frequency band of interest (e.g., 2.4 GHz for Bluetooth/WiFi, 2170 MHz for UMTS, or 1550 MHz for GPS). 
     A graph showing the wireless performance of device  10  when using two antennas (e.g., a hybrid PIFA/slot antenna formed from resonating element  54 - 1 A and a corresponding slot and an antenna formed from resonating element  54 - 2 ) is shown in  FIG. 11 . In the example of  FIG. 11 , the PIFA operating characteristics of the hybrid PIFA/slot antenna are used to cover the 850/900 MHz and the 1800/1900 MHz GSM cellular telephone bands, the slot antenna operating characteristics of the hybrid PIFA/slot antenna are used to provide additional gain and bandwidth in the 1800/1900 MHz range, and the antenna formed from resonating element  54 - 1 B is used to cover the frequency band centered at f n  (e.g., 2.4 GHz for Bluetooth/WiFi, 2170 MHz for UMTS, or 1550 MHz for GPS). This arrangement provides coverage for four cellular telephone bands and a data band. 
     If desired, the hybrid PIFA/slot antenna formed from resonating element  54 - 1 A and slot  70  may be fed using a single coaxial cable or other such transmission line. An illustrative configuration in which a single transmission line is used to simultaneously feed both the PIFA portion and the slot portion of the hybrid PIFA/slot antenna and in which a strip antenna formed from resonating element  54 - 1 B is used to provide additional frequency coverage for device  10  is shown in  FIG. 12 . Ground plane  54 - 2  may be formed from metal components in housing  10  including a metal frame coated with plastic (as an example) that has conductive edges  96  that are electrically connected to bezel  14  ( FIG. 1 ). 
     As shown in the somewhat schematic representation of  FIG. 12 , resonating element  54 - 1 B may have an L-shaped conductive strip formed from conductive branch  122  and conductive branch  120 . Branches  120  and  122  may be formed from metal that is supported by dielectric support structure  102 . With one suitable arrangement, the resonating element structures of  FIG. 12  are formed as part of a patterned flex circuit that is attached to antenna cap support structure  102  (e.g., by adhesive). 
     Coaxial cable  56 B or other suitable transmission line has a ground conductor connected to ground terminal  132  and a signal conductor connected to signal terminal  124 . Any suitable mechanism may be used for attaching the transmission line to the antenna. In the example of  FIG. 12 , the outer braid ground conductor of coaxial cable  56 B is connected to ground terminal  132  using metal tab  130 . Metal tab  130  may be shorted to housing  12 . Transmission line connection structure  126  may be, for example, a mini UFL coaxial cable connector. The ground of connector  126  may be shorted to terminal  132  and the center conductor of connector  126  may be shorted to conductive path  124 . Conductive path  124  may include circuit components (e.g., a capacitor) for impedance matching. 
     When feeding antenna  54 - 1 B, terminal  132  may be considered to form the antenna&#39;s ground terminal and the center conductor of connector  126  and/or conductive path  124  may be considered to form the antenna&#39;s signal terminal. The location along dimension  128  at which conductive path  124  meets conductive strip  120  can be adjusted for impedance matching. 
     Planar antenna resonating element  54 - 1 A of the illustrative hybrid PIFA/slot antenna of  FIG. 12  may have an F-shaped structure with shorter arm  98  and longer arm  100 . The lengths of arms  98  and  100  and the dimensions of other structures such as slot  70  in ground plane  54 - 2  may be adjusted to tune the frequency coverage and antenna isolation properties of device  10 . For example, length L of ground plane  54 - 2  may be configured so that the PIFA portion of the hybrid PIFA/slot antenna formed with resonating element  54 - 1 A resonates at the 850/900 MHz GSM bands, thereby providing coverage at frequency f 1  of  FIG. 11 . The length of arm  100  may be selected to resonate at the 1800/1900 MHz bands, thereby helping the PIFA/slot antenna to provide coverage at frequency f 2  of  FIG. 11 . The perimeter of slot  70  may be configured to resonate at the 1800/1900 MHz bands, thereby reinforcing the resonance of arm  100  and further helping the PIFA/slot antenna to provide coverage at frequency f 2  of  FIG. 11  (i.e., by improving performance from the solid line  63  to the dotted line  79  in the vicinity of frequency f 2 , as shown in  FIG. 6 ). If desired, the perimeter of slot  70  may be configured to resonate away from the 1800/1900 MHz bands (i.e., out-of-band). Slot  70  may also be used without the PIFA structures of  FIG. 12  (i.e., as a pure slot antenna). 
     In a PIFA/slot configuration, arm  98  can serve as an isolation element that reduces interference between the hybrid PIFA/slot antenna formed from resonating element  54 - 1 A and the L-shaped strip antenna formed from resonating element  54 - 1 B. The dimensions of arm  98  can be configured to introduce an isolation maximum at a desired frequency, which is not present without the arm. It is believed that configuring the dimensions of arm  98  allows manipulation of the currents induced on the ground plane  54 - 2  from resonating element  54 - 1 A. This manipulation can minimize induced currents around the signal and ground areas of resonating element  54 - 1 B. Minimizing these currents in turn may reduce the signal coupling between the two antenna feeds. With this arrangement, arm  98  can be configured to resonate at a frequency that minimizes currents induced by arm  100  at the feed of the antenna formed from resonating element  54 - 1 B (i.e., in the vicinity of paths  122  and  124 ). 
     Additionally, arm  98  can act as a radiating arm for element  54 - 1 A. Its resonance can add to the bandwidth of element  54 - 1 A and can improve in-band efficiency, even though its resonance may be different than that defined by slot  70  and arm  100 . Typically an increase in bandwidth of radiating element  51 - 1 A that reduces its frequency separation from element  51 - 1 B would be detrimental to isolation. However, extra isolation afforded by arm  98  removes this negative effect and, moreover, provides significant improvement with respect to the isolation between elements  54 - 1 A and  54 - 1 B without arm  98 . 
     As shown in  FIG. 12 , arms  98  and  100  of resonating element  54 - 1 A and resonating element  54 - 1 B may be mounted on support structure  102  (sometimes referred to as an antenna cap). Support structure  102  may be formed from plastic (e.g., ABS plastic) or other suitable dielectric. The surfaces of structure  102  may be flat or curved. The resonating elements  54 - 1 A and  54 - 1 B may be formed directly on support structure  102  or may be formed on a separate structure such as a flex circuit substrate that is attached to support structure  102  (as examples). 
     Resonating elements  54 - 1 A and  54 -B may be formed by any suitable antenna fabrication technique such as metal stamping, cutting, etching, or milling of conductive tape or other flexible structures, etching metal that has been sputter-deposited on plastic or other suitable substrates, printing from a conducive slurry (e.g., by screen printing techniques), patterning metal such as copper that makes up part of a flex circuit substrate that is attached to support  102  by adhesive, screws, or other suitable fastening mechanisms, etc. 
     A conductive path such as conductive strip  104  may be used to electrically connect the resonating element  54 - 1 A to ground plane  54 - 2  at terminal  106 . A screw or other fastener at terminal  106  may be used to electrically and mechanically connect strip  104  (and therefore resonating element  54 - 1 A) to edge  96  of ground plane  54 - 2  (bezel  14 ). Conductive structures such as strip  104  and other such structures in the antennas may also be electrically connected to each other using conductive adhesive. 
     A coaxial cable such as cable  56 A or other transmission line may be connected to the hybrid PIFA/slot antenna to transmit and receive radio-frequency signals. The coaxial cable or other transmission line may be connected to the structures of the hybrid PIFA/slot antenna using any suitable electrical and mechanical attachment mechanism. As shown in the illustrative arrangement of  FIG. 12 , mini UFL coaxial cable connector  110  may be used to connect coaxial cable  56 A or other transmission lines to antenna conductor  112 . A center conductor of the coaxial cable or other transmission line is connected to center connector  108  of connector  110 . An outer braid ground conductor of the coaxial cable is electrically connected to ground plane  54 - 2  via connector  110  at point  115  (and, if desired, may be shorted to ground plane  54 - 2  at other attachment points upstream of connector  110 ). A bracket may be used to ground connector  110  to bezel  14  at this portion of the ground plane. 
     Conductor  108  may be electrically connected to antenna conductor  112 . Conductor  112  may be formed from a conductive element such as a strip of metal (e.g., a copper trace) formed on a sidewall surface of support structure  102  (e.g., as part of the flex circuit that contains resonating elements  54 - 1 A and  54 - 1 B.). Conductor  112  may be directly electrically connected to resonating element  54 - 1 A (e.g., at portion  116 ) or may be electrically connected to resonating element  54 - 1 A through tuning capacitor  114  or other suitable electrical components. The size of tuning capacitor  114  can be selected to tune antenna  54  and ensure that antenna  54  covers the frequency bands of interest for device  10 . 
     Slot  70  may lie beneath resonating element  54 - 1 A of  FIG. 12 . The signal from center conductor  108  may be routed to point  106  on ground plane  54 - 2  in the vicinity of slot  70  using a conductive path formed from antenna conductor  112 , optional capacitor  114  or other such tuning components, antenna conductor  117 , and antenna conductor  104 . 
     The configuration of  FIG. 12  allows a single coaxial cable or other transmission line path to simultaneously feed both the PIFA portion and the slot portion of the hybrid PIFA/slot antenna. 
     Grounding point  115  functions as the ground terminal for the slot antenna portion of the hybrid PIFA/slot antenna that is formed by slot  70  in ground plane  54 - 2 . Point  106  serves as the signal terminal for the slot antenna portion of the hybrid PIFA/slot antenna. Signals are fed to point  106  via the path formed by conductive path  112 , tuning element  114 , path  117 , and path  104 . 
     For the PIFA portion of the hybrid PIFA/slot antenna, point  115  serves as antenna ground. Center conductor  108  and its attachment point to conductor  112  serve as the signal terminal for the PIFA. Conductor  112  serves as a feed conductor and feeds signals from signal terminal  108  to PIFA resonating element  54 - 1 A. 
     In operation, both the PIFA portion and slot antenna portion of the hybrid PIFA/slot antenna contribute to the performance of the hybrid PIFA/slot antenna. 
     The PIFA functions of the hybrid PIFA/slot antenna are obtained by using point  115  as the PIFA ground terminal (as with terminal  62  of  FIG. 7 ), using point  108  at which the coaxial center conductor connects to conductive structure  112  as the PIFA signal terminal (as with terminal  60  of  FIG. 7 ), and using conductive structure  112  as the PIFA feed conductor (as with feed conductor  58  of  FIG. 7 ). During operation, antenna conductor  112  serves to route radio-frequency signals from terminal  108  to resonating element  54 - 1 A in the same way that conductor  58  routes radio-frequency signal from terminal  60  to resonating element  54 - 1 A in  FIGS. 4 and 5 , whereas conductive line  104  serves to terminate the resonating element  54 - 1 A to ground plane  54 - 2 , as with grounding portion  61  of  FIGS. 4 and 5 . 
     The slot antenna functions of the hybrid PIFA/slot antenna are obtained by using grounding point  115  as the slot antenna ground terminal (as with terminal  86  of  FIG. 8 ), using the conductive path formed of antenna conductor  112 , tuning element  114 , antenna conductor  117 , and antenna conductor  104  as conductor  82  of  FIG. 8  or conductor  82 - 2  of  FIG. 10 , and by using terminal  106  as the slot antenna signal terminal (as with terminal  84  of  FIG. 8 ). 
     The illustrative configuration of  FIG. 10  demonstrates how slot antenna ground terminal  92  and PIFA antenna ground terminal  88  may be formed at separate locations on ground plane  54 - 2 . In the configuration of  FIG. 12 , a single coaxial cable may be used to feed both the PIFA portion of the antenna and the slot portion of the hybrid PIFA/slot antenna. This is because terminal  115  serves as both a PIFA ground terminal for the PIFA portion of the hybrid antenna and a slot antenna ground terminal for the slot antenna portion of the hybrid antenna. Because the ground terminals of the PIFA and slot antenna portions of the hybrid antenna are provided by a common ground terminal structure and because conductive paths  112 ,  117 , and  104  serve to distribute radio-frequency signals to and from the resonating element  54 - 1 A and ground plane  54 - 2  as needed for PIFA and slot antenna operations, a single transmission line (e.g., coaxial cable  56 A) may be used to send and receive radio-frequency signals that are transmitted and received using both the PIFA and slot portions of the hybrid PIFA/slot antenna. 
     If desired, other antenna configurations may be used that support hybrid PIFA/slot operation. For example, the radio-frequency tuning capabilities of tuning capacitor  114  may be provided by a network of other suitable tuning components, such as one or more inductors, one or more resistors, direct shorting metal strip(s), capacitors, or combinations of such components. One or more tuning networks may also be connected to the hybrid antenna at different locations in the antenna structure. These configurations may be used with single-feed and multiple-feed transmission line arrangements. 
     Moreover, the location of the signal terminal and ground terminal in the hybrid PIFA/slot antenna may be different from that shown in  FIG. 12 . For example, terminals  115 / 108  and terminal  106  can be moved relative to the locations shown in  FIG. 12 , provided that the connecting conductors  112 ,  117 , and  104  are suitably modified. 
     The PIFA portion of the hybrid PIFA/slot antenna can be provided using a substantially F-shaped conductive element having one or more arms such as arms  98  and  100  of  FIG. 12  or using other arrangements (e.g., arms that are straight, serpentine, curved, have 90° bends, have 180° bends, etc.). The strip antenna formed with resonating element  54 - 1 B can also be formed from conductors of other shapes. Use of different shapes for the arms or other portions of resonating elements  54 - 1 A and  54 - 1 B helps antenna designers to tailor the frequency response of antenna  54  to its desired frequencies of operation and maximize isolation. The sizes of the structures in resonating elements  54 - 1 A and  54 - 1 B can be adjusted as needed (e.g., to increase or decrease gain and/or bandwidth for a particular operating band, to improve isolation at a particular frequency, etc.). 
     A somewhat schematic cross-sectional view of an illustrative handheld electronic device  10  in accordance with an embodiment of the present invention is shown in  FIG. 13 . As shown in  FIG. 13 , ground plane  54 - 2  may include bezel  14 , display  16 , housing  12 , and other conductive components  52  in region  170  of device  10 . Housing  12  in region  18  may be made up of a plastic cosmetic cap, which allows antenna resonating elements (e.g., elements  54 - 1 A and  54 - 1 B of  FIG. 12 ) to be placed in region  171 . Bezel  14  may be used to mount display  16  to housing  12 . Electrical components  52  such as printed circuit boards, flex circuits, integrated circuits, batteries, and other devices may be mounted within portion  170  of device  10 . The conductive structures within portion  170  can be electrically connected to one another so that they serve as ground for the antenna(s) in device  10 . Bezel  14  can also be electrically connected to portion  170  (e.g., through welds, metal screws, metal clips, press-fit contact between adjacent metal parts, wires, etc.). 
     As a result of these electrical connections, bezel  14  and conductive portions of device  10  in region  170  form conductive ground plane  54 - 2 , as shown in  FIG. 14 . The conductive portions of device  10  in region  170  may lie on one side of dotted line  23 , whereas at least some of the conductive portions of bezel  14  may extend outwards from portions  170  and may lie on the other side of dotted line  23 , thereby defining slot  70 . 
     With one suitable configuration, slot  70  may have an area equal to the opening between bezel  14  and the conductive portions of device  10  that lie on the opposite side of dotted line  23 . With other suitable configurations, one or more electrical components may overlap with the otherwise rectangular opening formed between bezel  14  and region  170  to form slot with smaller dimensions (rectangular or non-rectangular). 
     An exploded perspective view of an illustrative handheld electronic device  10  in accordance with an embodiment of the present invention is shown in  FIG. 15 . As shown in  FIG. 15 , handheld electronic device  10  may have a conductive bezel such as conductive bezel  14  for securing display  16  or other such planar components to lower housing portion  12 . A gasket such as gasket  150  may be interposed between bezel  14  and the exposed surface of display  16 . Gasket  150  may be formed of silicone, polyester film, or other soft plastic (as an example). Gasket  150  may have any suitable cross-sectional shape. For example, gasket  150  may have a circular cross section (i.e., gasket  150  may be an o-ring having, for example, a 0.6 mm diameter), gasket  150  may have a rectangular cross-section, etc. Gasket  150  may help to seal the surface of display  16  to prevent debris from entering device  10 , may help to center the display within bezel  14 , and may help to hide potentially unsightly portions of display  16  from view. Display  16  may have one or more holes or cut-away portions. For example, display  16  may have hole  152  to accommodate button  19  and hole  182  to accommodate sound from a speaker. 
     If desired, display  16  may be touch sensitive. In touch sensitive arrangements, display  16  may have a touch sensor such as touch sensor  154  that is mounted below the uppermost surface of display screen  16  just above the liquid crystal display (LCD) element. Frame subassembly  180  may receive the display and touch sensor components associated with display  16 . Antenna structures may be housed behind cosmetic plastic cap  212 . Cosmetic plastic cap  212  may also cover components such as a microphone and speaker. Additional components (e.g., an additional speaker, audio jacks, a SIM card tray, buttons such as a hold button, volume button, ringer select button, and camera module, etc.) may be housed in region  158  at the opposite end of device  10 . 
     Bezel  14  may be secured using any suitable technique (e.g., with prongs that mate with holes in a spring fastened to housing  12 , with fasteners, with snaps, with adhesive, using welding techniques, using a combination of these approaches, etc.). As shown in  FIG. 15 , bezel  14  may have portions  160  that extend downwards. Portions  160  may take the form of prongs, rails, and other protruding features. Portions  160  may be configured so that the outer perimeter of portions  160  mates with structures along the inner perimeter of housing  12  when frame subassembly  180  is mounted in housing  12  and when bezel  14  is used to attach display  16  to device  10 . 
     Portions  160  may have screw holes  162  through which screws may mate with corresponding threaded standoffs when attaching bezel  14  to housing subassembly  180 . The screws and other conductive structures (e.g., welds, wires, springs, brackets, etc.) may be used to electrically connect bezel  14  to grounded elements within device  10 . For ease of assembly, frame subassembly  180  may have tabs, snaps, or other attachment structures. For example, frame subassembly  180  may have holes  164  that receive mating fingers on display  16 . Prongs (ears)  186  may receive screws that are used in securing and grounding bezel  14  to dock connector  20 . 
     Frame subassembly  180  may include a frame that is based on a thin (e.g., 0.3 mm) stainless steel layer onto which plastic features have been overmolded and attached (e.g., with a heat staking process) or other suitable structural components. Frame top  156  may be recessed within frame subassembly  180  to accommodate the touch sensor and other portions  154  of display  16 . Sensors such as an ambient light sensor and a proximity sensor may be mounted in region  184 . 
     An exploded perspective rear view of the illustrative device of  FIG. 15  is shown in  FIG. 16 . As shown in  FIG. 16 , housing  12  may have ground tab  190 . Tab  190  may be used to help ground antenna resonating element  54 - 1 A to conductive housing  12 . To ensure that tab  190  makes good electrical contact to housing  12 , anodized portions of housing  12  may be removed using laser etching. 
     Logo  192  may be formed of a metal such as stainless steel (as an example). Logo  192  may be attached to housing  12  using adhesive or other suitable attachment mechanisms. Buttons such as a volume button, hold button, and ringer mode select button may be located in region  194 . 
     Camera module  196  may be attached to frame subassembly  180 . Transceivers, such as transceiver  52 A and  52 B of  FIG. 3  may also be attached to frame subassembly  180 . As shown in  FIG. 16 , transceiver  52 B may be housed in conductive can  198  and transceiver  52 A may be housed in conductive can  200 . Cans such as cans  198  and  200  serve as radio-frequency shielding enclosures that reduce electromagnetic interference (EMI). SIM tray  202  on frame subassembly  180  may be used to receive SIM cards. 
     Cosmetic cap  212  may have a recess such as recess  204  that accommodates dock connector  20  when cap  212  is attached to device  10 . Cap  212  may have inwardly protruding snap keys (plastic beams) that are guided through holes in the frame during assembly and that snap into bezel  14 , thereby preventing cap  212  from becoming detached from device  10  during use. Bezel  14  may have rails  208  that guide cosmetic cap  212  during assembly and that help to retain cap  212  on device  10 . 
     Antenna resonating elements such as antenna resonating elements  54 - 1 A and  54 - 1 B may be formed from conductive traces on flex circuit  210 . Flex circuit  210  may be mounted on a plastic antenna cap (as an example). 
     The exploded view of device  10  in  FIG. 17  shows an illustrative arrangement for coaxial cables  56 A and  56 B and shows an illustrative shape for flex circuit  210 . Flex circuit  210  may have slots  227  and other features to help flex circuit  210  conform to the curved surface of antenna cap  102 . Screw  218  and clip  248  (also sometimes referred to as a bracket or spring) may be used to ground coaxial cable connector  110  to bezel  14  at location  222 . Screw  220  and clip  246  (also sometimes referred to as a bracket or spring) may be used to ground bezel  14  to dock connector  20  at location  224 . Clip  246  may also be electrically connected to conductive strip  104  ( FIG. 12 ). 
     Cables  56 A and  56 B may have exposed portions at which their outer ground conductors (e.g., braid conductors or other outer conductors) are exposed (i.e., not covered by plastic or other insulating materials). These exposed portions allow cables  56 A and  56 B to be grounded to bezel  14  and the rest of ground plane  52 - 4  along their length. This provides good grounding for cables  56 A and  56 B and prevents cables  56 A and  56 B from acting as antenna elements. Without grounding along their lengths, cables  56 A and  56 B might radiate radio-frequency signals reflected back from antenna resonating elements  52 - 1 A and  52 - 1 B. 
     The exposed conductive portions of cables  56 A and  56 B form electrical connections between the ground conductors of the cables and ground plane  54 - 2 . Cables  56 A and  56 B may be bare of insulator along their entire lengths or along only certain isolated segments. For example, cables  56 A and  56 B may have no insulator directly under ferrules  226 . Ferrules  226  (or other suitable conductive fasteners) may be connected to the conductive braid in the exposed segments of cables  56 A and  56 B by crimping. One or more brackets or other suitable conductive fastening members (sometimes referred to as J-brackets) may be used to structurally and electrically connect ferrules  226  to ground plane  54 - 2  (i.e., by shorting ferrules  226  to conductive portions of device  10  such as the metal portions of frame subassembly  180  and bezel  14 ). 
     An interior perspective view of a conductive housing portion  12  is shown in  FIG. 18 . As shown in  FIG. 18  ground tab  190  may be part of a ground bracket  228 . Ground bracket  228  may have a tab under region  230  that slides into a mating channel in housing  12 . The anodized surface of housing  12  in this region may be stripped using laser etching, thereby allowing the tab in region  230  to make good electrical contact between bracket  228  (and its tab  190 ) and housing  12 . 
     Metal strips such as strip  234 , which are sometimes referred to as brackets or rails, may be formed of cast magnesium and may be attached to housing  12  using adhesive (as an example). For example, a rubbery glue may be used to attached strips such as strip  234  to housing  12 . Metal strips such as strip  234  may be spaced apart from the sidewalls of housing  12  to form channels such as channel  232 . A spring in each channel may have holes that engage mating hooks on bezel  14 . 
     Bracket  242  may be used to hold an audio jack, vibrator, and a button wire flex circuit. Bracket  242  may be formed from a metal such as cast magnesium. 
     Top ground bracket  240  may have fingers that engage housing  12 . The anodized surface of housing  12  may be removed by laser etching in the finger contact region to ensure that ground bracket  240  makes good electrical contact to housing  12 . Ground plane components in device  10  that are placed on top of ground bracket  240  may make contact to housing  12  through ground bracket  240 . 
     Logo  192  may be shorted to housing  12  to ensure that logo  192  does not electrically float relative to housing  12 . Laser etching may be used to remove a portion of the anodized surface of housing  12  under region  236  to ensure a good electrical contact between logo  192  and housing  12 . Logo  192  may be adhesively bonded to housing  12 . In one embodiment, logo  192  may be bonded to housing  12  using a thermal bonding agent and an epoxy resin bonding agent. 
     Pin  238  may serve as a pivot for a SIM card ejection tray arm. 
     A top view of the end of an illustrative device  10  with its cosmetic end cap removed is shown in  FIG. 19 . Microphone rubber boot  244  may form a seal between the cosmetic cap and microphone inlet port  260 . Microphone inlet port  260  may be used to channel sound to a microphone in device  10 . Electrical connections may be made at locations  254 . A screw may be used at each location  254 . The screws may engage threaded portions of a dock flange associated with dock connector  20 . The screws pass through bezel tabs  186  on bezel  14 . On the left size of dock connector  20  (in the orientation of  FIG. 19 ), the screw also passes through spring  246  and flex circuit  210 . Spring  246  may be formed from a metal such as stainless steel. A conductive trace (conductive strip  104  of  FIG. 12 ) is located adjacent to spring  246 . When the screw is screwed into the frame, the spring  246  presses outwards between the flex circuit trace and bezel tab  186 , thereby making good electrical contact at point  106  ( FIG. 12 ) between bezel  14  and conductive strip  104  ( FIG. 12 ). 
     Coaxial cable connector  110  may be snapped into a mating connector on flex circuit  210 . Ground clip or bracket  248  (which is shown in a partially uncompressed state in  FIG. 19 ) may be used to help hold connector  110  in place and may be used to form an electrical contact to bezel  14  (see point  115  of  FIG. 12 ). 
     Frame portion  253  may be used to support cosmetic cap  212  in the event that external pressure is placed on cosmetic cap  212  (i.e., in the event that device  10  is inadvertently dropped). 
     Brackets  250  may be connected to or formed as part of brackets  234  of  FIG. 18  and may be screwed into the frame of device  10  (e.g., frame portions  252 ) using screws  254 . 
     Capacitor  258  may form part of path  124  ( FIG. 12 ). Epoxy  256  may be used to provide capacitor  258  with structural support (i.e., to protect capacitor  258  from cracking during assembly). Capacitor  114  may also be protected using epoxy. 
     Flex circuit  210  may be mounted to antenna cap  102  using pressure sensitive adhesive. Slots  227  allow the conductive traces of resonating element such as resonating element  54 - 1 A to conform to the curved surface of cap  102 . The conductive traces may be formed of copper or other suitable conductive material. 
     At location  262 , coaxial cable  56 A may be routed away from the antenna traces, so that cable  56 A may be maintained closer to ground plane  54 - 2  (e.g., bezel  14 ) and further away from resonating element  54 - 1 B. 
     Grounding clip  190  may engage ferrule  226  to ensure that ferrule  226  and coaxial cable  56 B are grounded to housing  12 . Screw  276  may be used to hold down grounding clip  190  on antenna cap  102 . Trace  264  may form part of the ground for antenna resonating element  54 - 1 B in conjunction with ground tab  190 . Conductive branches  120  and  122  may form part of antenna resonating element  54 - 1 B. 
     Alignment posts  266  may mate with corresponding holes in flex circuit  212 . This helps to align flex circuit  210  to antenna cap  102  during assembly. 
     Ferrule  226  of  FIG. 19  is shown in more detail in  FIG. 20 . As shown in  FIG. 20 , a biasing member such as spring  268  may be located between part of antenna cap  102  and underside  274  of ferrule  226  adjacent to frame cross member  280 . Spring  268  may be formed of urethane or other suitable resilient material. During assembly, ferrule  226  may be pushed downwards against spring  268 , causing arms  270  and  272  to splay outwards away from each other. When under tension in this way, spring  268  biases ferrule  226  upwards in direction  278  against tab  190  of bracket  228  ( FIG. 19 ), so that ferrule  226  (i.e., the ground conductor of coaxial cable  56 B) is shorted to ground plane  54 - 2  (e.g., housing  12 ). 
     Spring  268  is also shown (behind frame cross member  280 ) in the perspective view of  FIG. 21 . Polyester film  282  may be used to protect flex circuit  288  from damage. Adhesive  284  may be used to mount battery  204  to frame  290 . Polyester film  286  may be used to protect battery  204  (e.g., by preventing puncture damage to the relatively thin battery case). 
     As shown in  FIG. 22 , coaxial cable  56 A may be connected to printed circuit board  292  of transceiver  52 A using coaxial cable connector  296 . Electromagnetic shielding cases  200  and  294  may be used to provide radio-frequency EMI shielding for the circuitry of transceiver  52 A. For example, shield  294  may be a metal shield that is soldered to printed circuit board  292  to shield one or more transceiver integrated circuits, whereas shield  200  may be a metal shield that is attached by snaps to shield discrete components associated with transceiver  52 A. 
     Frame  290  may have a sheet metal core (e.g., a stainless steel sheet of 0.3 mm thickness) that is surrounded by a plastic overmold. The overmolded plastic parts that make up frame  290  may provide detailed structures that would be difficult to fabricate from stainless steel. Metal screws  297  may be used to secure conductive bezel  14  to exposed sheet metal portions  298  of frame  290 , thereby shorting bezel  14  to frame  290  and ensuring that both bezel  14  and frame  290  form part of ground plane  54 - 2 . 
     Ferrules  226  or other suitable conductive fasteners may be electrically connected to frame  290  and bezel  14  using a bracket (e.g., a J-bracket) or other suitable conductive member. The bracket may be connected to ferrules  226  by soldering, welding, or by physical contact (i.e., by crimping the bracket to ferrules  226  with or without soldering or welding). With one suitable arrangement, the conductive member is formed of metal (e.g., magnesium or aluminum) and has bendable extensions (i.e., fingers). The bendable extensions may be crimped over the ferrules or other conductive fasteners during assembly to attach the conductive member to the ferrules and the coaxial cables. If device  10  needs to be reworked or recycled, the coaxial cables may be released from the conductive member and device  10  by bending the extensions away from the conductive fasteners on the cables. 
     A detailed view of an illustrative arrangement for forming a connection between coaxial cable  56 A and the antenna structures of device  10  is shown in  FIG. 23 . As shown in  FIG. 23 , coaxial cable  56 A may be connected to flex circuit  210  using a coaxial cable connector  110 . The center conductor  108  ( FIG. 12 ) of cable  56 A and connector  110  may be connected to antenna conductor  112 . Capacitor  114  or other tuning components may be used to connect conductor  112  to conductor  304 . Conductor  304  may be connected to portion  116  of antenna resonating element  54 - 1 A. As with the traces that make up antenna resonating element  54 - 1 A on the top surface of flex circuit  210 , conductors  112  and  114  may be formed as traces on flex circuit  210 . If desired, flex circuit  210  may have traces on two sides. Use of a single-sided flex circuit arrangement, in which traces  112 ,  114 , and the other antenna traces are formed on a single side of flex circuit  210  may help to reduce the cost and complexity of the antenna. Flex circuit traces may be formed of any suitable conductor such as copper. 
     Epoxy  306  may be used to provide structural support for capacitor  114  (e.g., to prevent capacitor  114  from being damaged during assembly). Adhesive  308  may be used to attach flex circuit  210  to the end face of antenna cap  102 . Frame  290  may have screw hole  302 . Bracket  248  ( FIGS. 17 and 19 ) may be attached to frame  290  by screwing a screw (i.e., screw  218  of  FIG. 17 ) into hole  302 . Spring  246  can be attached to dock connector  20  using screw  220  of  FIG. 17 . When screw  220  has been screwed into place (through one of bezel prongs  186  of  FIG. 15 , bezel  14 , clip  246 , conductive strip  104  of antenna resonating element  54 - 1 A, and dock connector  20  are shorted together as described in connection with forming the connections at point  106  of ground plane  54 - 2  in  FIG. 12 . 
     A perspective top view of device  10  with internal structures (such as display  16 ) removed is shown in  FIG. 24 . As shown in  FIG. 24 , flex circuit  288  may be used to form a bus that conveys signals from dock connector  20  to processing circuitry located towards end  326  of device  10 . The overall shape of antenna slot  70  is formed by the boundaries of bezel  14  and frame  290  (which lies along dotted line  23 ). This overall shape can be influenced by electrical components that lie within its boundaries. Certain components, such as microphone  244  and speaker  316  may be isolated from the antenna using inductors (as an example). Other components (e.g., button  320 ) may be isolated from the antenna using inductors or resistors (as an example). Isolating components in this way can eliminate or substantially reduce any impact these components might have on the effective area of slot  70 . 
     Dock connector  20  may contain metal that overlaps the otherwise rectangular shape of slot  70 . Moreover, flex circuit  288  contains signal traces and ground traces. The conductive material in these traces acts as a portion of the ground plane of device  10  and therefore can alter the effective shape of slot  70 . As shown in the illustrative arrangement of  FIG. 24 , flex circuit  288  may be routed around the edge of slot  70  immediately adjacent to bezel  14 . 
     Speaker flex circuit  312  may be used to route signals from flex circuit  288  to speaker module  316 . Speaker flex circuit  312  may be connected to flex circuit bus  288  by soldering (as an example). Components  314  may include isolation inductors and other electrical components for supporting the operation of speaker module  316 . Electrical components  318  may be used to support the operation of dock connector  20 . 
     Stiffener  322  may be used to support flex circuit  288  as flex circuit  288  passes towards microphone  244  and button  320 . A flex circuit extension (i.e., a tail of flex circuit  288 ) in the vicinity of region  324  may be used to connect the leads of menu button  320  to flex circuit  288 . Menu button  320  may be a dome switch or any other suitable user interface control. Components  330  may be formed using inductors (e.g., traditional wire-wrapped inductors or ferrite chip inductors) or resistors. Components  330  may be used to help isolate button  320  from the antennas of device  10  (e.g., to prevent button  320  from significantly influencing the shape of slot  70 ). Electrical components  328  may include inductors for isolating microphone  244  from the antennas of device  10 . 
     Pressure sensitive adhesive  332  may be used to mount battery  204 . Foam  334  may help to prevent damage to display  16 . Alignment posts  336  on dock connector  20  may be used to help align flex circuit  288 . 
     As shown in  FIG. 25 , extension  338  of flex circuit  288  may be used to make electrical connections between flex circuit  288  and button  320 . Ground bracket  248  may have an indentation such as indentation  340  that mates with a rib on frame  290 . 
       FIG. 26  shows how dock connector  20  may have 30 pins  342  (as an example). A flange formed from metal mounting tabs  344  may be welded to the main body of dock connector  20 . Screws  220  and  346  may be screwed into threads on metal mounting tabs  344  through holes in tabs  186  ( FIG. 15 ) of bezel  14 . Screw  348  may be screwed into frame  290  to secure grounding bracket  248  to the frame. Screws such as screw  348  may be screwed into portions of frame  290  that are added to frame  290  after the plastic overmolded portion of frame  290  has been formed. These added portions of frame  290  may, for example, be added using a heat staking process. 
     The presence of spring  246 , which forms part of an antenna terminal for the hybrid PIFA/slot antenna, helps to reduce the tolerance required in connecting bezel  14  to the antenna. 
     As shown in  FIG. 27 , speaker  316  may have an associated port  350 , through which sound may emanate during device operation. In the rear view of  FIG. 27 , speaker port  350  is located on the right side of housing  12  and microphone port  260  is located on the left size of housing  12 . This is merely illustrative. Speaker port  350  and microphone port  260  may be located on any suitable portion of housing  12  (e.g., front face, rear face, top side, bottom side, left side, or right side). As shown in  FIG. 27 , screws  254  may hold housing brackets  250  to the frame. The view of  FIG. 27  does not include antenna cap  102 , so components such as speaker module  316  are visible beneath flex circuit  210 . 
     A perspective view of the interior of device  10  is shown in  FIG. 28 . Battery leads  352  may be used to convey power from battery  204  to the electronics of device  10 . Leads  352  may be soldered to printed circuit boards such as printed circuit board  292 . There may be any suitable number of leads  352  (e.g., ground, positive, and negative). Screws  354  may be used to screw circuit boards such as circuit board  292  to the frame of device  10 . 
     Radio-frequency shielding (sometimes called EMI shielding) may be provided in the form of conductive cans  200  and  198 . Shielding cans  200  and  198  (which are sometimes referred to as EMI enclosures, radio-frequency enclosures, or shielding housings) may be constructed from metal or other suitable conductive materials. Can  200  may be used to shield transceiver  52 A ( FIG. 3 ), whereas can  198  may be used to shield transceiver  52 B ( FIG. 3 ). 
     Coaxial cable  56 B may be connected to the transceiver in can  198  using coaxial cable connector  376 . Coaxial cable  56 A may be connected to the transceiver in can  200  using coaxial cable connector  296 . 
     A conductive foam pad such as pad  358  may be affixed to the top of can  200  to help ground can  200 . When the cover of the housing of device  10  is installed, conductive foam  358  may rub against an exposed portion of the interior of the housing, thereby electrically shorting can  200  to the housing. Can  200  may also have bent up fingers  356  that rub against the housing to short can  200  to the housing. Bent up fingers  370  on can  198  may be used to short can  198  to the housing. 
     To ensure that fingers such as fingers  370  and  356  make good electrical contact with the housing, the portions of the housing that contact the fingers may be processed to remove any nonconductive coatings. For example, if the housing is an anodized aluminum housing that has a nonconductive anodized coating, the anodized layer may be removed by laser etching in the regions of the housing that contact fingers  370  and  356  and the regions of the housing that contact other shorting structures such as conductive foam  358 . Cans  198  and  200  may be used to shield one or more layers of printed circuit board (e.g., multiple stacked printed circuit boards). These circuit boards may be used to mount integrated circuits and/or discrete components. 
     Camera module  196  may have a lens  372 . Lens  372  may be a fixed focal length lens (as an example). Camera module  196  may be used to acquire still images and video images (e.g., video containing audio). Camera flex circuit  377  may be used to electrically connect camera module  196  to the printed circuit boards of device  10 . 
     Recess  360  may be configured to receive components such as an audio jack and other input-output components. Holes  374  may be formed in the touch screen module of display  16  to reduce weight. 
     As shown in  FIG. 29 , device  10  may use a connector such as connector  378  to receive a flex circuit plug. The flex circuit plug and its associated flex circuit may be used to convey electrical signals to the circuitry of device  10  from components such as an audio jack, volume button, hold button, and ringer select button. 
     As shown in  FIG. 30 , SIM card tray  202  may have a spring  380 . Spring  380  may have a bent portion  382 . When compressed, bent portion  382  can press upwards (in the orientation of  FIG. 30 ) against a SIM card to hold the SIM card in place in tray  202 . 
     A cross-sectional view of housing  12  is shown in  FIG. 31 . As shown in  FIG. 31 , a conductive member such as J-clip  384  may be used to secure coaxial cables  56 A and  56 B. J-clip  384  may be electrically connected to conductive portions of frame  290  (e.g., exposed metal portions), thereby shorting ferrules  226  (and thus the outer braid conductor of coaxial cables  56 A and  56 B) to frame  290  and the other portions of ground plane  54 - 2 . 
     J-clip  384  may have a generally horizontal planar base member such as base member  390  and a generally vertical planar member such as vertical planar member  388 . J-clip base  390  may be welded to the metal of frame  290  or may otherwise be electrically and mechanically connected to frame  290 . Base  390  may have alignment holes  400 . During assembly, an assembly tool with mating protrusions may engage holes  400  and hold J-clip  384  in place for welding. 
     J-clip  384  may have bendable extensions such as clip extensions  386 . Extensions  386  may be manually crimped in place over coaxial cables  56 A and  56 B during assembly. If desired, extensions  386  may, at a later time, be bent backwards to release coaxial cables  56 A and  56 B. This releasable fastening arrangement allows for rework. For example, cables  56 A and  56 B can be replaced. The ability to remove cables  56 A and  56 B from device  10  may also be advantageous when disassembling device  10  (e.g., when recycling all or part of device  10 ). Extensions  386  may have any suitable shape. For example, extensions  386  may be provided in the form of relatively narrow fingers that are easy to crimp and uncrimp. Alternatively, extensions  386  may be provided in the form of relatively wider tabs. Wide tab shapes may make good electrical contact with ferrules  226 , but may be harder to crimp and uncrimp than narrower extension structures. 
     Spring  392  may be formed from metal or other suitable springy conductive material. Spring  392  may be glued or otherwise mounted in a channel between the side wall of housing  12  and housing bracket  234 . During assembly, fingers on bezel  14  engage holes on spring clip  392 , thereby securing bezel  14  to housing  12 . 
     Housing bracket  234  may be glued or otherwise affixed to housing  12 . Allowable excess glue  394  is shown above bracket  234 . The housing bracket that is shown in  FIG. 31  is sometimes referred to as the left housing bracket of device  10 . Device  10  may also have a corresponding right housing bracket. 
     Display  16  may be mounted to housing  12  using bezel  14  and gasket  150 . Display  16  may have a planar glass element such as glass element  404  and a touch sensitive element such as touch sensitive element  402 . Frame  290  may have a conductive element such as sheet metal plate  396 . Sheet metal plate  396  may be electrically and mechanically connected to sheet metal plate  397  (e.g., by welding, by gluing, by using fasteners, etc.). Foam  398  may be used to help protect display  16  from shock (e.g., in the event that device  10  is dropped). 
     A top view of device  10  in the vicinity of J-clip  384  is shown in  FIG. 32 . As shown in the  FIG. 32  example, extensions  386  may be used to crimp coaxial cables  56 A and  56 B at various segments along their lengths. In the example of  FIG. 32 , there are four sets of extensions  386  of substantially equal size that are spaced equally along edge  406  of device  12 . If desired, the segments of cables that are electrically connected to extensions  386  may be of different sizes or there may be a different number of extensions  386 . For example, there may be more than four extensions  386 , there may be two larger extensions  386  and two smaller extensions  386 , etc. There may also be only a single extension  386  along edge  406 , although arrangements with more than one extension are generally easier to uncrimp when desired for rework or recycling and are therefore generally preferred. 
     As shown in  FIG. 33 , grounding bracket  248  may be used to short the ground connector portion of coaxial cable connector  110  to bezel  14 . 
       FIG. 34  shows a partially cross-sectional interior view of device  10 . As shown in  FIG. 34 , bracket  234  may have a long, relatively uninterrupted rail portion such as rail  412  and, at intervals, may have extending fingers  410 . Spring  392  may have a relatively uninterrupted rail portion  416  (mostly hidden from view in  FIG. 34 ) and, at intervals, may have extending fingers  418 . Fingers  410  of bracket  234  and fingers  418  of spring  392  may be interleaved as shown in  FIG. 34 . Bracket  234  may have holes  414  in rail  412 . During manufacturing, an assembly tool may hold bracket  234  by engaging holes  414  with mating prongs. Spring  392  may have holes such as rectangular holes  420 . Bezel  14  may have mating prongs. During assembly, the mating prongs from bezel  14  may slide into rectangular holes  420  to secure bezel  14  in place relative to housing  12  of device  10 . 
     As shown in  FIG. 35 , rail  416  of spring  394  may have alignment holes  422 . During manufacturing, an assembly tool may hold spring  394  using prongs that mate with holes  422 . 
     A bracket such as top bracket  440  (e.g., a bracket formed of a conductive material such as magnesium or aluminum) may be attached to housing  12  at the top of device  10  (e.g., using screws, glue, etc.). A bracket such as sheet metal bracket  424  may be attached to top bracket  440  using screws such as screws  426 . A flex circuit for a hold button or other suitable button may be attached to bracket  424 . A protective film such as polyester protective film  428  may cover the flex circuit to prevent damage. Flex circuit  436  may be used to route signals to circuitry  432  from a hold button mounted to bracket  428  (as an example). Circuitry  432  to which flex circuit  436  is routed may include jack  378  ( FIG. 29 ). 
     SIM card ejector arm  436  may swing about pivot  238 . Spring  438  may bias SIM card ejector arm  436 , so that arm  436  may be used to eject a SIM card from device  10 . Flex circuit  434  may make contact with overlapping printed circuit boards (not shown in  FIG. 35 ). 
     A detailed cross-sectional view of bezel  14  in the vicinity of spring  392  is shown in  FIG. 36 . As shown in  FIG. 36 , bezel  14  may have extended members such as prongs  442  that mate with corresponding rectangular holes  420  in fingers  418  of spring  392 . Spring  392  may be mounted between housing  12  and bracket  234 , so when bezel prongs  442  protrude into spring  392 , bezel  14  is held into place. 
     As described in connection with  FIG. 14 , a handheld electronic device with a conductive bezel may define a slot  70  that is roughly rectangular in shape (as an example). In a device such as the illustrative handheld electronic device described in connection with  FIGS. 15-36 , components that contain conductive elements may overlap with the rectangular slot that is formed by bezel  14  and the conductive portion of housing  12  and frame  290 . These overlapping components may alter the shape of slot  70 . 
     As shown in  FIG. 37 , for example, in region  18  of device  10 , slot  70  may have a roughly rectangular shape arising from the rectangular opening defined by bezel  14  (to the left of dotted line  23  in  FIG. 37 ) and housing/frame  12 / 290  (to the right of dotted line  23 ). Dock connector  20 , which may be formed of a conductive material such as metal (e.g., stainless steel), may be grounded to bezel  14 . As a result, dock connector  20  may form part of the ground plane  54 - 2  for device  10 . In the example of  FIG. 37 , dock connector  20  protrudes into the otherwise rectangular opening of slot  70 , thereby altering its rectangular shape. In particular, dock connector  20  adds a length of 2LA to the interior perimeter of slot  70 . Flex bus connector  288  also contains conductive elements (e.g., copper ground and signal traces). Flex connector  288  therefore also alters the shape of slot  70 , resulting in a shortening of the length of perimeter P of 2LB. 
     As described in connection with dotted line  79  of  FIG. 6 , there may be a peak antenna resonance associated with slot  70 . The position of the peak resonance may be determined by the length of perimeter P. In general, the peak resonance of the slot antenna portion of the antenna of device  10  is located where the radio-frequency signal wavelength is equal to the length of perimeter P. In device  10 , the perimeter P of slot  70  may be determined by the size of the rectangular opening formed by bezel  14  and frame/housing  12 / 290  and by the modifications to this rectangular opening that arise from the presence of connector  20  and flex circuit  288 . If desired, the locations and shapes of dock connector  20  and flex circuit  288  may be selected so that the perimeter length reduction (2LB) that arises from the presence of flex circuit  288  cancels out the perimeter length addition (2LA) that arises from the presence of dock connector  20  (i.e., lengths LA and LB may be substantially equal). 
     As shown in  FIG. 25 , components such as microphone  244 , button  320 , and speaker  316  may also overlap with slot  70 . These components may be prevented from significantly altering the value of antenna slot perimeter P by using isolation circuitry. For example, inductors may be placed on the leads of microphone  244  (e.g., in circuitry  328 ). Similarly, inductors may be placed on the leads of speaker  316  (e.g., in circuitry  314 ). Inductors may also be placed on the leads of button  320  (see, e.g., components  330 ). At low frequencies, such as at frequencies in the kilohertz range and below, which includes the audio frequencies handled by microphone  328  and speaker  316 , the inductors allow current to pass freely (i.e., the inductors act as short circuits). At radio frequencies (i.e., at 300 MHz or more, and particularly at frequencies of 850 MHz to 2.4 MHz or greater), the inductors have a large impedance and act as open circuits, thereby isolating microphone  244 , speaker  316 , and button  320 . When microphone  244 , speaker  316 , and button  320  are isolated from the radio-frequency antenna signals, microphone  244 , speaker  316 , and button  320  do not affect the value of perimeter P for slot  70  and do not load the antenna resonating elements  54 - 1 A and  54 - 1 B. 
     The isolating inductors that are used to isolate electrical components such as microphone  244 , speaker  316 , and button  320  may be conventional wire-wrapped inductors or may be somewhat smaller inductors of the type that are sometimes referred to as ferrite chip inductors. An advantage of using ferrite chip inductors is that they have a small size. An advantage of using conventional wire-wrapped inductors is that they tend not to create the types of antenna losses that might arise when using ferrite chip inductors in close proximity to antenna resonating elements. 
     If desired, components such as microphone  244 , speaker  316 , and button  320  can be isolated using isolation elements other than inductors, such as resistors. As shown in  FIG. 38 , button  320  may, as an example, be isolated using isolation elements  330  (e.g., resistors). Resistors  330  may be placed on the leads of button  320  between button  320  and control circuitry  36  (e.g., where shown by components  330  in  FIG. 25 ). In a fully assembled handheld electronic device, button  320  may overlap antenna resonating elements such as antenna resonating elements  54 - 1 A and  54 - 1 B ( FIG. 19 ). 
     The close proximity of button  320  and the antenna resonating elements can create antenna losses. Moreover, the overlap between button  320  and antenna slot  70  can affect the shape of slot  70  and its perimeter P, potentially affecting the location of the resonant peak of the handheld device antenna. By selecting resistors  330  of sufficient size, the impact of button  320  on perimeter P can be eliminated or substantially reduced and the possibility of antenna losses due to the close proximity of button  320  and the antenna resonating elements can be eliminated or substantially reduced. 
     With one suitable arrangement, the values of resistors  330  may be about 3000 ohms. This value is sufficiently high to at least partially isolate button  320 , while allowing direct current (DC) control signals (e.g., relatively low frequency button press signals in the kilohertz range or lower) to pass from button  320  to control circuitry  36 . Although described primarily in the context of isolating menu button  320  from radio-frequency signals, resistors may be used to isolate any suitable type of electrical component that is potentially subject to radio-frequency interference (e.g., any other electrical component that overlaps slot  70  and/or antenna resonating elements such as antenna resonating elements  54 - 1 A and  54 - 1 B). 
       FIG. 39  shows how an electronic component such as menu button  320  may overlap resonating elements  54 - 1 A and  54 - 1 B (i.e., in a top view from the front face or rear face of device  10 ). 
       FIG. 40  shows an illustrative coaxial cable of the type that may be used for coaxial cables  56 A and  56 B in handheld electronic device  10 . As shown in  FIG. 40 , cable  56  may have a center conductor  444 . Dielectric layer  446  may surround center conductor  444 . Ground conductor  448  may surround dielectric layer  446 . Segments of insulator  450  may surround ground conductor  448  at one or more locations along the length of coaxial cable  56 . Cable  56  may have one or more exposed (bare) segments of ground conductor  448  at one or more locations  452  along the length of cable  56 . At least some of locations  452  may be spaced so that they are equidistant from each other. If desired, some of locations  452  may be spaced at locations that are not equidistant with respect to each other. There may be any suitable number of locations  452  (e.g., one, two, three, more than three, etc.). There may also be any suitable number of insulating segments  450  (e.g., no segments, one segment, two segments, three segments, more than three segments, etc.). Ferrules  226  or other suitable conductive fasteners may be crimped or otherwise mechanically and electrically attached to ground conductor  448  of cable  56  in locations  452 . If desired, additional layers of material (e.g., insulating and conductive material) may be included in cable  56 . The layers of insulator and conductor that are shown in  FIG. 40  are merely illustrative. 
     Cables such as cable  56  of  FIG. 40  with alternating exposed ground conductor and insulated segments may be formed using any suitable technique (e.g., by selectively covering a bare cable with insulating segments, by selectively stripping an insulated cable, or by using a combination of these techniques). Insulating materials that may be used in cable  56  include polytetrafluoroethylene, polyvinylchloride, etc. Conductive materials that may be used in cable  56  include copper, aluminum, metallized polyester tape, etc. 
     An antenna performance graph showing how the resonant peak of a handheld electronic device antenna having a ground plane with a slot can be adjusted by positioning electronic components to change the inner perimeter of the slot is shown in  FIG. 41 . The resonant frequency peak of a communications band being handled by an antenna that contains a slot of a given inner perimeter may be f a  (as an example). The inner perimeter of the slot is generally equal to about one wavelength of the radio-frequency signal. Proper operation of the antenna at frequency f a  may be ensured by positioning components such as a dock connector, flex circuit, conductive housing, and conductive bezel relative to one another to achieve an inner perimeter of a desired length. 
     When designing an antenna to operate in another frequency band, the shape of the antenna slot and its inner perimeter can be changed accordingly. For example, if it is desired to design an antenna for operation at a frequency f b  that is larger than frequency f a , the inner perimeter P may be shortened. This will cause the resonant frequency of the antenna to shift from the frequency f a  (solid line  500 ) to f b  (dotted line  502 ), as shown in  FIG. 41 . One way to shorten the inner perimeter of an antenna slot in an antenna ground plane involves positioning a dock connector, flex circuit or other component(s) in device  10  so that an end of the slot is truncated (as an example). In general, any suitable adjustments may be made to the positions of the dock connector, flex circuit, bezel, conductive housing, or other conductive components in a handheld electronic device to achieve a desired slot shape and inner perimeter. 
     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.