PATENT DOCUMENT

Publication Number: US-7880678-B2
Application Number: US-6117608-A
Country: US
Kind Code: B2

Title: Removable antennas for electronic devices

Abstract:
A removable antenna is provided for an electronic device such as a laptop computer. An antenna resonating element is mounted within the antenna. Magnetic coupling structures are used to magnetically attach the antenna to the electronic device. The magnetic coupling structures couple the antenna resonating element to circuitry in the electronic device. The electronic device may have an antenna receptacle that holds the antenna in a stowed position and allows the antenna to extend to an extended position. A user may extend the antenna by sliding the antenna or by rotating the antenna to its extended position. The coupling structures may allow the antenna to break away from the electronic device without damage.

Claims:
1. Apparatus comprising:
 an electronic device having a first magnetic coupling structure; and 
 a removable antenna that is removable during operation of the electronic device, that has a second magnetic coupling structure that is coupled to the first magnetic coupling structure, and that has an antenna resonating element, wherein at least one of the first and second magnetic coupling structures comprises a magnet, wherein the removable antenna is configured to rotate into an extended position, and wherein the first and second magnetic coupling structures hold the removable antenna in the extended position and are configured to allow the removable antenna to be accidently dislodged from the electronic device without damage. 
 
     
     
       2. The apparatus defined in  claim 1  wherein the electronic device comprises a computer. 
     
     
       3. The apparatus defined in  claim 1  wherein the electronic device further comprises transceiver circuitry that generates and receives radio-frequency signals over a communications path. 
     
     
       4. The apparatus defined in  claim 3  wherein the first and second magnetic coupling structures are configured to electrically couple the antenna resonating element to the communications path so that the radio-frequency signals pass between the antenna resonating element and the transceiver circuitry. 
     
     
       5. The apparatus defined in  claim 1  wherein the removable antenna further comprises a first magnetic attraction element, wherein the electronic device further comprises a second magnetic attraction element, and wherein the first and second magnetic attraction elements are configured to help secure the removable antenna to the electronic device when the removable antenna is in a stowed position. 
     
     
       6. The apparatus defined in  claim 1  wherein the removable antenna is configured to rotate between a stowed position and the extended position. 
     
     
       7. The apparatus defined in  claim 6  wherein the first and the second magnetic coupling structures are configured to limit non-rotational movement between the removable antenna and an antenna receptacle in the electronic device. 
     
     
       8. The apparatus defined in  claim 7  wherein the first magnetic coupling structure comprises a cylindrical protrusion, wherein the second magnetic coupling structure comprises a corresponding cylindrical cavity. 
     
     
       9. Apparatus comprising:
 an electronic device having a first springless coupling structure and having a radio-frequency transceiver; 
 a communications path that conveys radio-frequency signals between the radio-frequency transceiver and the first springless coupling structure; and 
 a removable antenna having a second springless coupling structure that is removably coupled to the first springless coupling structure and that has an antenna resonating element, wherein at least one of the first and second springless coupling structures comprises a magnet, and wherein the antenna resonating element is electrically coupled to the communications path through the first and second springless coupling structures so that the radio frequency signals are conveyed between the radio-frequency transceiver and the antenna resonating element over the communications path and through the first and second springless coupling structures. 
 
     
     
       10. The apparatus defined in  claim 9  wherein the removable antenna has a longitudinal axis, wherein the removable antenna is configured to reciprocate along its longitudinal axis, and wherein the removable antenna is configured to reciprocate between a stowed position and an extended position. 
     
     
       11. The apparatus defined in  claim 10  wherein the first and second springless coupling structures are configured to break the electrical coupling between the antenna resonating element and the radio-frequency signals carried on the communications path when the removable antenna reciprocates away from the extended position. 
     
     
       12. The apparatus defined in  claim 10  wherein the electronic device further comprises a first magnetic attraction element, wherein the removable antenna further comprises a second magnetic attraction element, and wherein the first and the second magnetic attraction elements are configured to guide the removable antenna along its longitudinal axis as the removable antenna reciprocates between the stowed position and the extended position. 
     
     
       13. The apparatus defined in  claim 12  wherein the electronic device has portions defining an antenna receptacle, wherein the first and the second magnetic attraction elements and the first and second springless coupling structures are configured to attract the removable antenna to the antenna receptacle, and wherein the removable antenna and the antenna receptacle are configured so that the removable antenna is removable without damaging the removable antenna. 
     
     
       14. The apparatus defined in  claim 9  wherein the first springless coupling structure further comprises a ball, wherein the second springless coupling structure further comprises a detent structure that is configured to couple with the ball, and wherein the ball is attracted to the detent structure by a magnetic attraction force between the ball and the detent structure. 
     
     
       15. The apparatus defined in  claim 14  wherein the electronic device comprises a portable computer. 
     
     
       16. Apparatus comprising:
 an electronic device having a first coupling structure and having a radio-frequency transceiver; 
 a communications path that conveys radio-frequency signals between the radio-frequency transceiver and the first coupling structure; and 
 an unextendable removable antenna having a second coupling structure that is coupled to the first coupling structure and having an antenna resonating element, wherein at least one of the first and second coupling structures comprises a magnet, and wherein the antenna resonating element is electrically coupled to the communications path through the first and second coupling structures so that the radio frequency signals are conveyed between the radio-frequency transceiver and the antenna resonating element over the communications path and through the first and second coupling structures. 
 
     
     
       17. The apparatus defined in  claim 16  wherein the first and second coupling structures are configured so that the unextendable removable antenna is removable without damaging the unextendable removable antenna and wherein the electronic device comprises a portable computer. 
     
     
       18. A method of using a removable antenna in an electronic device having a springless antenna receptacle and transceiver circuitry, comprising:
 when the removable antenna is in the springless antenna receptacle, magnetically coupling the removable antenna to the springless antenna receptacle, wherein the removable antenna is magnetically coupled to the springless antenna receptacle such that the removable antenna can be accidently dislodged from the electronic device without damage; 
 with the transceiver circuitry, generating and receiving radio-frequency signals over a communications path; 
 electrically coupling the removable antenna to the transceiver circuitry by electrically coupling an antenna resonating element in the removable antenna to the communications path; and 
 with the removable antenna, transmitting and receiving the radio-frequency signals with the antenna resonating element. 
 
     
     
       19. The method defined in  claim 18  wherein electrically coupling the removable antenna to the transceiver circuitry further comprises electrically coupling the antenna resonating element in the removable antenna to the communications path with a first magnetic coupling structure in the removable antenna and a second magnetic coupling structure in the springless antenna receptacle. 
     
     
       20. The method defined in  claim 18  wherein the removable antenna has a first magnetic attraction element, wherein the springless antenna receptacle has a second magnetic attraction element, wherein the first and second magnetic attraction elements comprise at least one electrically conductive material, and wherein electrically coupling the removable antenna to the transceiver circuitry further comprises electrically coupling the antenna resonating element in the removable antenna to the communications path through the electrically conductive material of the first and second magnetic attraction elements.

Description:
BACKGROUND 
     This invention relates to antennas, and more particularly, to removable antennas for electronic devices. 
     It may be desirable to include wireless communications capabilities in an electronic device. Electronic devices may use wireless communications to communicate with wireless base stations. For example, electronic devices may communicate using the Wi-Fi® (IEEE 802.11) bands at 2.4 GHz and 5.0 GHz and the Bluetooth® band at 2.4 GHz. Electronic devices may also use other types of communications links. For example, electronic devices such as 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). Communications are also possible in data service bands such as the 3G data communications band at 2100 MHz (commonly referred to as UMTS or Universal Mobile Telecommunications System). 
     Many popular housing materials such as metal have a high conductivity. This poses challenges when designing an antenna for an electronic device with this type of housing. An internal antenna would be shielded by a high-conductivity housing, so internal antenna designs are often not considered practical in electronic devices with conductive cases. On the other hand, external antenna designs that protrude excessively from a device housing may have an unattractive appearance. External antenna designs may also be susceptible to damage. 
     It would therefore be desirable to be able to provide a satisfactory antenna for an electronic device with a conductive case. 
     SUMMARY 
     In accordance with an embodiment of the present invention, removable antennas for electronic devices are provided. A removable antenna may be magnetically coupled to an electronic device. The antenna and the electronic device may have corresponding coupling structures. The coupling structures may be magnetic and/or ferromagnetic and may be integrated into the structure of the antenna and the structure of the electronic device. The coupling structures may provide a magnetic force that magnetically couples the antenna to the electronic device. With one suitable arrangement, the coupling structures may be formed in distinct portions of the antenna and the electronic device. Because the antenna is magnetically coupled to the electronic device, the antenna may be removed from the electronic device without damaging the antenna, the electronic device, or the coupling structures. This helps to prevent damage in the event that the antenna is accidently dislodged. 
     The antenna need not be extendable. In embodiments where the antenna is not extendable, the coupling structures on the electronic device may be configured to blend in with surrounding portions of the electronic device. Non-extendable removable antenna arrangements may allow a user of the electronic device to easily swap antennas of varying shapes and sizes. 
     If desired, the antenna may be extendable. The electronic device may have a conductive housing. The antenna may have improved transmission and reception efficiencies when the antenna is placed in an extended position away from the conductive housing. In the antenna&#39;s extended position, the antenna&#39;s performance may be enhanced by the increase in separation (e.g., compared to a stowed position) between an antenna resonating element in the antenna and the ground plane of the metal housing of the electronic device. The antenna resonating element in the antenna may be formed from any suitable antenna design. For example, the antenna resonating element may be formed from a flex circuit containing a strip of conductor, a piece of stamped metal foil, a length of wire, etc. 
     In addition to physically coupling the antenna and the electronic device together, the coupling structures may couple the antenna resonating element structures in the antenna to a transceiver in the electronic device through a communications path. The coupling of the antenna resonating element to the communications path may be magnetic, so that no damage will result when the coupling structures are separated. The coupling structures may be also conductive. Conductive coupling structures may be used to electrically connect the communications path and the antenna resonating element while physically attracting the antenna to the electronic device using the magnetic properties of the coupling structures. 
     A removable and extendable antenna may be configured to extend by rotating about an axis. For example, an antenna may be extended by rotating the antenna about an axis centered near one of the ends of the antenna. 
     A removable and extendable antenna may also be configured to extend by reciprocating along its length. For example, an antenna may extend by sliding lengthwise from its stowed position to its extended position. 
     Coupling structures may provide a magnetic force that helps guide an antenna from its stowed position to its extended position. For example, in embodiments in which the antenna is configured to extend or retract by reciprocating along its length, the coupling structures may help to guide the antenna in a straight line along the length of the antenna. 
     The coupling structures may provide feedback to a user of the electronic device when the antenna is in its extended or its stowed position. For example, the coupling structures may be configured to make a noise when the antenna enters its extended or its stowed position or may be configured to serve as a detent. 
     A removable and extendable antenna may be configured to blend in with surrounding portions of an electronic device when the antenna is in a stowed position. For example, the antenna may have an outer surface that is appropriately colored, textured, and shaped such that the antenna in its stowed position appears as a nearly seamless or unobtrusive portion of the electronic device. Some or all of the coupling structures may contribute to a magnetic force that aligns the antenna with the electronic device in its stowed state such that the antenna properly blends in with the surrounding portions of the electronic device. 
     Signals may be conveyed from an antenna structure or other removable device and an electronic device using magnetic coupling structures. The signals that are conveyed through the magnetic coupling structures in this way may include DC signals such as signals associated with a sensor or signals associated with the presence or absence of an antenna resonating element or other device. 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative electronic device and an illustrative extendable, removable antenna in a stowed state in accordance with an embodiment of the present invention. 
         FIG. 2  is a perspective view of an illustrative electronic device and an illustrative removable antenna in an attached state in accordance with an embodiment of the present invention. 
         FIG. 3  is a schematic diagram of an illustrative electronic device in accordance with an embodiment of the present invention. 
         FIG. 4  is an exploded perspective view of an illustrative electronic device and an illustrative extendable, removable antenna in accordance with an embodiment of the present invention. 
         FIG. 5  is a cross-sectional side view of an illustrative antenna receptacle in an electronic device and an illustrative extendable, removable antenna in accordance with an embodiment of the present invention. 
         FIG. 6  is a cross-sectional side view of an illustrative extendable, removable antenna and an illustrative antenna receptacle in an electronic device in accordance with an embodiment of the present invention. 
         FIG. 7  is a cross-sectional side view of an illustrative extendable, removable antenna in an extended state and an illustrative antenna receptacle in an electronic device in accordance with an embodiment of the present invention. 
         FIG. 8  is a cross-sectional side view of an illustrative extendable, removable antenna in a stowed state and an illustrative antenna receptacle in an electronic device in accordance with an embodiment of the present invention. 
         FIG. 9  is a cross-sectional view of an illustrative extendable, removable antenna in an extended state and an illustrative antenna receptacle in an electronic device in accordance with an embodiment of the present invention. 
         FIG. 10  is a cross-sectional view of an illustrative magnetic coupling structure in an extendable, removable antenna and an illustrative magnetic coupling structure in an antenna receptacle of an electronic device in accordance with an embodiment of the present invention. 
         FIG. 11  is a cross-sectional view of an illustrative magnetic coupling structure in an extendable, removable antenna and an illustrative magnetic coupling structure in an antenna receptacle of an electronic device in accordance with an embodiment of the present invention. 
         FIG. 12  is a cross-sectional view of an illustrative magnetic coupling structure in an extendable, removable antenna and an illustrative magnetic coupling structure in an antenna receptacle of an electronic device in accordance with an embodiment of the present invention. 
         FIG. 13  is a cross-sectional view of another illustrative magnetic coupling structure in an extendable, removable antenna and an illustrative magnetic coupling structure in an antenna receptacle of an electronic device in accordance with an embodiment of the present invention. 
         FIG. 14  is a cross-sectional view of an illustrative partly decoupled magnetic coupling structure in an extendable, removable antenna and an illustrative magnetic coupling structure in an antenna receptacle of an electronic device in accordance with an embodiment of the present invention. 
         FIG. 15  is a cross-sectional view of illustrative magnetic coupling structures in a rotatable antenna coupling arrangement in accordance with an embodiment of the present invention. 
         FIG. 16  is a cross-sectional view of illustrative magnetic coupling structures in a rotatable antenna coupling arrangement in accordance with an embodiment of the present invention. 
         FIG. 17  is a schematic circuit diagram of illustrative equipment with circuitry that may be electrically coupled with magnetic coupling structures in accordance with an embodiment of the present invention. 
         FIG. 18  is a cross-sectional view of illustrative magnetic coupling structures in an extendable, removable antenna and an illustrative magnetic coupling structure in an antenna receptacle of an electronic device in accordance with an embodiment of the present invention. 
         FIG. 19  is a cross-sectional view of an illustrative magnetic coupling structure in an extendable, removable antenna and illustrative magnetic coupling structures in an antenna receptacle of an electronic device in accordance with an embodiment of the present invention. 
         FIG. 20  is cross-sectional view of illustrative flexible mounting structures that may support an illustrative magnetic coupling structure in an antenna receptacle of an electronic device in accordance with an embodiment of the present invention. 
         FIG. 21  is an exploded perspective view of an illustrative electronic device and an illustrative extendable, removable antenna in accordance with an embodiment of the present invention. 
         FIG. 22  is an exploded perspective view of an illustrative electronic device and an illustrative extendable, removable antenna in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention relates generally to antennas, and more particularly, to removable antennas for wireless electronic devices. 
     The wireless electronic devices may be any suitable electronic devices. As an example, the wireless electronic devices may be desktop computers or other computer equipment. The wireless electronic devices may also be portable electronic devices such as laptop computers or small portable computers of the type that are sometimes referred to as ultraportables. With one suitable arrangement, the portable electronic devices may be handheld electronic devices. 
     Examples of portable and handheld electronic devices include cellular telephones, media players with wireless communications capabilities, handheld computers (also sometimes called personal digital assistants), remote controls, global positioning system (GPS) devices, and handheld gaming devices. The devices may also be hybrid devices that combine the functionality of multiple conventional devices. Examples of hybrid 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, has music player functionality and supports web browsing. These are merely illustrative examples. 
     An illustrative electronic device such as a portable electronic device in accordance with an embodiment of the present invention is shown in  FIG. 1 . Device  10  may be any suitable electronic device. As an example, device  10  may be a laptop computer. 
     Device  10  may handle communications over one or more communications bands. For example, wireless communications circuitry in device  10  may be used to handle cellular telephone communications in one or more frequency bands and data communications in one or more communications bands. Typical data communications bands that may be handled by the wireless communications circuitry in device  10  include the 2.4 GHz band that is sometimes used for Wi-Fi® (IEEE 802.11) and Bluetooth® communications, the 5.0 GHz band that is sometimes used for Wi-Fi communications, the 1575 MHz Global Positioning System band, and 3G data bands (e.g., the UMTS band at 1920-2170). These bands may be covered by using single band and multiband antennas. For example, cellular telephone communications can be handled using a multiband cellular telephone antenna and local area network data communications can be handled using a multiband wireless local area network antenna. As another example, device  10  may have a single multiband antenna for handling communications in two or more data bands (e.g., at 2.4 GHz and at 5.0 GHz). 
     Device  10  may have housing  12 . Housing  12 , which is sometimes referred to as a case, may be formed of any suitable materials including plastic, glass, ceramics, metal, other suitable materials, or a combinations of these materials. 
     Housing  12  or portions of housing  12  may also be formed from conductive materials such as metal. An illustrative metal housing material that may be used is anodized aluminum. Aluminum is relatively light in weight and, when anodized, has an attractive insulating and scratch-resistance 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 antenna in device  10 . For example, metal portions of housing  12  and metal components in housing  12  may be shorted together to form a ground plane in device  10  or to expand a ground plane structure that is formed from a planar circuit structure such as a printed circuit board structures (e.g., a printer circuit board structure used in forming antenna structures for device  10 ). 
     Device  10  may have one or more buttons such as buttons  14 . Buttons  14  may be formed on any suitable surface of device  10 . In the example of  FIG. 1 , buttons  14  have been formed on the top surface of device  10 . As an example, buttons  14  may form a keyboard on a laptop computer. 
     If desired, device  10  may have a display such as display  16 . Display  16  may be a liquid crystal diode (LCD) display, an organic light emitting diode (OLED) display, a plasma 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 . Device  10  may also have a separate touch pad device such as touch pad  25 . 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. Buttons  14  may, if desired, be arranged adjacent to display  16 . With this type of arrangement, the buttons may be aligned with on-screen options that are presented on display  16 . A user may press a desired button to select a corresponding one of the displayed options. 
     Device  10  may have circuitry  18 . Circuitry  18  may include storage, processing circuitry, and input-output components. Wireless transceiver circuitry in circuitry  18  may be used to transmit and receive radio-frequency (RF) signals. Communications paths such as coaxial communications paths and microstrip communications paths may be used to convey radio-frequency signals between transceiver circuitry and antenna structures in device  10 . As shown in  FIG. 1 , for example, communications path  24  may be used to convey signals between antenna structure  26  and circuitry  18 . Communications path  24  may be, for example, a coaxial cable that is connected between an RF transceiver (sometimes called a radio) and a multiband antenna. Antenna structures such as antenna structure  26  may be located adjacent to a corner of device  10  as shown in  FIG. 1  or in other suitable locations. For example, antenna structure  26  may be located along a top edge of display  16 , along any edge of device  10 , or may be located in a suitable portion of any planar surface of device  10 . 
     Antenna structure  26  may be removable and extendable. Antenna structure  26  may be magnetically coupled to device  10  to allow the antenna structure to be removed without damaging antenna structure  26  or device  10 . The use of magnetic coupling may facilitate easy replacement of antenna structure  26  and may facilitate break away of the antenna structure when a force is applied that could otherwise damage the antenna structure. 
     Antenna structure  26  may translate or rotate from a stowed position (e.g., the position shown in  FIG. 1 ) into an extended position. The extended position of antenna structure  26  may be used to increase the efficiency of signal reception and transmission. For example, the extended position of antenna structure  26  may enhance wireless communications functionality by increasing the separation between the ground plane of device  10  and antenna resonating elements in antenna structure  26  relative to the separation between the ground plane and the antenna resonating elements in the stowed position. 
     Antenna structure  26  may be configured such that in the stowed position the antenna structure is flush, or nearly flush, with the surrounding portions of device  10 . The stowed position of the antenna structure may improve the visual appearance of device  10 . For example, when the antenna structure is in the stowed position, the antenna structure may blend in with the surrounding portions of device  10  and thereby reduce visual clutter. In the stowed position, the antenna structure is also generally less vulnerable to accidental detachment. 
     As illustrated in  FIG. 1 , antenna structure  26  may reciprocate along its longitudinal axis  28 . Antenna structure  26  may reciprocate along longitudinal axis  28  when transitioning between its stowed state and its extended state. 
     In another embodiment, antenna structure  26  may rotate about an axis such as axis  30 . Antenna structure  26  may rotate about axis  30  when transitioning between its stowed state and its extended state. 
     Device  10  may have sensors to determine whether antenna structure  26  is attached or detached and to determine whether antenna structure  26  is in an extended or stowed position. Communications path  32  may be used to convey signals between these sensors and circuitry  18 . Communications path  32  may be implemented using any suitable cable or wires. 
     As shown in  FIG. 2 , device  10  may have an unextendable removable antenna structure such as antenna structure  27  that does not reciprocate or rotate relative to housing  12 . Unextendable removable antenna structure  27  may be magnetically coupled to device  10  to allow the antenna structure to be removed without damaging antenna structure  27  or device  10 . Antenna structure  27  may be mounted on device  10  at any suitable attachment point. For example, antenna structure  27  may be attached to the top or side edge of device  10 . As shown by dotted lines  70 , antenna structure  27  may be removed in any desired direction excluding directions that would require the antenna structure to pass through device  10 . A removable antenna structure such as antenna structure  27  may allow a user to utilize antenna structures of any suitable size or shape including those that may not have blended with surrounding portions of device  10  while still retaining the benefits of a magnetic coupling that allows the antenna structure to break away undamaged. 
     A schematic diagram of an embodiment of electronic device  10  is shown in  FIG. 3 . Electronic device  10  may be a notebook computer, a tablet computer, an ultraportable computer, a mobile telephone, a mobile telephone with media player capabilities, a handheld computer, a remote control, a game player, a global positioning system (GPS) device, a combination of such devices, or any other suitable portable or handheld electronic device. 
     As shown in  FIG. 3 , electronic device  10  may include storage  72 . Storage  72  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  74  may be used to control the operation of device  10 . Processing circuitry  74  may be based on a processor such as a microprocessor and other suitable integrated circuits. With one suitable arrangement, processing circuitry  74  and storage  72  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  74  and storage  72  may be used in implementing suitable communications protocols. Communications protocols that may be implemented using processing circuitry  74  and storage  72  include internet protocols, wireless local area network protocols (e.g., IEEE 802.11 protocols—sometimes referred to as Wi-Fi®), protocols for other short-range wireless communications links such as the Bluetooth® protocol, protocols for handling 3G data services such as UMTS, cellular telephone communications protocols, etc. 
     Input-output devices  76  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 , keys  14 , and touchpad  25  of  FIG. 1  are examples of input-output devices  76 . 
     Input-output devices  76  may include user input-output devices  78  such as buttons, touch screens, joysticks, click wheels, scrolling wheels, touch pads, key pads, keyboards, microphones, cameras, speakers, tone generators, vibrating elements, etc. A user can control the operation of device  10  by supplying commands though user input devices  78 . 
     Display and audio devices  80  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  80  may also include audio equipment such as speakers and other devices for creating sound. Display and audio devices  80  may contain audio-video interface equipment such as jacks and other connectors for external headphones and monitors. 
     Wireless communications devices  82  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 (e.g., antenna structures such as antenna structure  26  of  FIG. 1 ), and other 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  84  and computing equipment  86 , as shown by paths  88 . Paths  88  may include wired and wireless paths. Accessories  84  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 play audio and video content). 
     Computing equipment  86  may be any suitable computer. With one suitable arrangement, computing equipment  86  is a computer that has an associated wireless access point 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 electronic device  10 ), or any other suitable computing equipment. 
     The antenna structures and wireless communications devices of device  10  may support communications over any suitable wireless communications bands. For example, wireless communications devices  82  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 2100 MHz (commonly referred to as UMTS or Universal Mobile Telecommunications System), Wi-Fi® (IEEE 802.11) bands (also sometimes referred to as wireless local area network or WLAN bands), the Bluetooth® band at 2.4 GHz, and the global positioning system (GPS) band at 1575 MHz. Wi-Fi bands that may be supported include the 2.4 GHz band and the 5.0 GHz bands. The 2.4 GHz Wi-Fi band extends from 2.412 to 2.484 GHz. Commonly-used channels in the 5.0 GHz Wi-Fi band extend from 5.15-5.85 GHz, so the 5.0 GHz band is sometimes referred to by the 5.4 GHz approximate center frequency for this range (i.e., these communications frequencies are sometimes referred to as making up a 5.4 GHz communications band). Device  10  can cover these communications bands and/or other suitable communications bands with proper configuration of the antenna structures in wireless communications circuitry  82 ). 
     As shown in  FIG. 4 , device  10  may have a removable, extendable antenna structure such as antenna structure  26 . Antenna structure  26  may be magnetically coupled to device  10  to allow the antenna structure to be intentionally or accidently removed without damaging antenna structure  26  or device  10 . 
     In the  FIG. 4  example, antenna structure  26  is shown near device  10  in approximately its stowed state. The actual position of the antenna structure in its stowed state is approximately that of line  28 . If the antenna structure were to be moved into alignment along line  28  by moving the antenna structure in the direction of arrow  41 , the antenna structure would be in the approximate position of its stowed state. 
     Antenna structure  26  may be extended from a stowed position that may maximize the aesthetics of device  10  to an extended position that may maximize the performance and efficiency of the antenna structure by reciprocating along its longitudinal axis (e.g., axis  28 ). During reciprocation along axis  28 , antenna structure  26  may be magnetically coupled to device  10 . In another example, antenna structure  26  may rotate about an axis such as the axis of line  30  when transitioning between its stowed position and its extended position. Magnetic coupling may be used to hold antenna structure  26  in place on device  10  during rotational movement. 
     Antenna structure  26  may be configured to break away from device  10  to prevent damage to the antenna structure and device  10 . For example, if antenna structure  26  translates too far along line  28 , antenna structure  26  may break away from device  10 . Antenna structure  26  may also break away when a force acts upon the antenna structure to either push or pull the antenna structure away from device  10 . For example, if the antenna structure is struck in direction  40 , the magnetic force that couples device  10  and antenna structure  26  may give way before damage occurs to the antenna structure or the device. 
     Optional sensors  34  and communications paths  32  may be used by device  10  to determine whether antenna structure  26  is attached and/or whether the antenna structure is in a stowed state or in an extended state. Sensors  34  may send position signals to circuitry  18  indicating when antenna structure  26  is in position to transmit and receive radio signals (i.e., when the antenna structure is in its extended position). Circuitry  18  may use position signals from sensors  34  to enable or disable wireless communications devices  82  that transmit and receive radio-frequency signals using an antenna resonating element in antenna structure  26 . 
     Antenna structure  26  may be mechanically and/or electrically coupled to device  10  using coupling structures such as coupling structures  36  and  38  on device  10  and corresponding coupling structures on antenna structure  26 . Coupling structure  36  and a corresponding coupling structure in antenna structure  26  couple communications path  24  to an antenna resonating element in antenna structure  26 . Coupling structures (or portions of coupling structure) may be made of one or more magnetic elements (magnets) and/or one or more ferromagnetic elements (e.g., iron bars). Magnetic or ferromagnetic portions of coupling structures may produce a magnetic force that couples antenna structure  26  to device  10 . 
     An elongated coupling structure such as coupling structure  38  may be used to produce a magnetic force that couples antenna structure  26  to device  10  as structures  26  moves relative to device  10 . Coupling structure  38  may, for example, be configured to guide antenna structure  26  along longitudinal axis  28  when the antenna structure is extended or retracted by reciprocating along longitudinal axis  28 . 
     An illustrative antenna receptacle that may be a part of an electronic device such as device  10  is shown in  FIG. 5 . Antenna receptacle  120  may be formed from portions of device  10  that surround antenna structure  26  when antenna structure  26  is in its stowed position. The antenna receptacle of  FIG. 5  may have a curved edge such as edge  39  that maintains aesthetic features of antenna structure  26  and device  10  when the antenna structure is in a stowed state. Edge  39  may allow the antenna structure to rotate about an axis centered on coupling structure  36  (e.g., in one of directions  370 ) to an extended state, or vice versa, without impinging on the edge of the antenna receptacle. 
     As shown in the example of  FIG. 5 , coupling structure  38  may be reduced in size relative to the arrangement of  FIG. 4  and may serve to retain the antenna structure in correct alignment inside the antenna receptacle when the antenna structure is in its stowed state. Coupling structure  38  may provide acoustic and/or tactile feedback when the antenna structure transitions from a nearly stowed state to its stowed state. Coupling structure  38  may also provide acoustic and/or tactile feedback when the antenna structure transitions from its stowed state to a partially deployed state. Feedback on the position of antenna structure  26  may also be provided by sensing the position of antenna structure  26  using one or more position sensors (e.g., sensors  34 ), processing the position information from the sensors using processor  74 , and providing a visual or audio signal to a user with devices  76 . 
       FIG. 6  shows a cross sectional view of antenna structure  26  and an antenna receptacle in device  10 . The antenna structure shown in  FIG. 6  is aligned as if in a stowed state but is vertically offset to facilitate the illustration of the various components of the antenna receptacle and the antenna structure. If the antenna structure were moved in direction  41 , the antenna structure&#39;s magnetic coupling structures (e.g., structures  44  and  46 ) would mate with corresponding magnetic coupling structures in device  10  (e.g., structures  38  and  36 ) and the antenna structure would be in its stowed state. 
     Coupling structure  44  may be a tip attraction element that serves to attract the tip of antenna structure  26  to device  10  when the antenna structure is in its stowed position. The attraction of the tip of antenna structure  26  to device  10  via coupling structure  44  (and coupling structure  36 ) may enhance the visual appearance of antenna structure  26  in its stowed position by holding the antenna structure in its proper stowed position. 
     Coupling structure  42  may be a coupling structure in antenna structure  26  that couples antenna resonating element  48  to communications path  24  in device  10  when the antenna is in its extended position. Coupling structures such as structures  36 ,  38 ,  42 ,  44 , and  46  may be made of one or more magnetic elements and/or one or more ferromagnetic elements. For example, structures  42 ,  44 , and  46  may be magnets and structures  36  and  38  may be ferromagnetic. 
     In the stowed state of antenna structure  26 , the antenna structure and device  10  may have a uniform and clutter-free visual appearance. Outer portions of structure  26  may be aligned with surrounding portions of device  10 . Antenna structure  26  may be configured such that a force acting to move the antenna structure in direction  40  may overcome the magnetic attraction between antenna structure  26  and device  10  before damage occurs to either antenna structure  26  or device  10 . 
     Coupling structures  36 ,  38 ,  42 ,  44 , and  46  may be made of ferromagnetic or magnetic materials. In one embodiment, all of or portions of each of the coupling structures are made from magnetic materials. In another embodiment, some of the coupling structures are magnetic and their mating coupling structures are ferromagnetic. Coupling structures such as structures  36 ,  38 ,  42 ,  44 , and  46  may be integrated into antenna structure  26  and/or device  10  or may be more distinct portions as shown in  FIG. 6 . In embodiments where the coupling structures are more integrated into antenna structure  26  and/or device  10 , the coupling structures may improve the visual appearance of the antenna and device  10  by reducing visual clutter. In general, there may be any suitable number of coupling structures associated with a given device  10 . 
     When antenna structure  26  is in its stowed state, coupling structure  36  may secure the tip of antenna structure  26  by magnetically attracting a tip attraction element such as structure  46 . The attraction between structures  36  and  46  may provide tactile feedback in the form of an acoustic and/or tactile signal when the antenna structure transitions into or out of its stowed state. The attraction between structures  36  and  46  may serve to secure the tip of antenna structure  26  and thereby align the outside of antenna structure  26  with surrounding portions of device  10  and increase the aesthetic appearance of antenna structure  26  and device  10  when the antenna structure is in its stowed state. 
     Coupling structure  36  of  FIG. 6  may couple communications path  24  through coupling structure  42  of antenna structure  26  to antenna resonating element  48 . Coupling structure  42  may be configured to provide feedback to a user that coupling structures  36  and  42  have coupled or decoupled (i.e., antenna structure  26  has fully extended or started retracting from the extended position) in the form of an acoustic and/or tactile signal. 
     When the antenna structure is transitioning between its extended and stowed states, coupling structure  44  may help to guide antenna structure  26  along its longitudinal axis and along structure  38  which may act as a track for antenna structure  26 . With one suitable arrangement, coupling structure  44  (e.g., attraction element  44 ) may provide the majority of the attractive force that couples antenna structure  26  to device  10  and that keeps the antenna structure aligned when it is reciprocating between its extended and stowed states. 
     Antenna resonating element  48  may be a part of antenna structure  26 . Antenna resonating element  48  may form part of an antenna for wireless communications devices  82 . Antenna resonating element  48  may be based on any suitable antenna technology. For example, antenna resonating element  48  may be a part of a dipole antenna, a horn antenna, a monopole antenna, a single band antenna, a multiband antenna, etc. With one suitable arrangement, antenna resonating element  48  serves as one pole of an antenna and a ground plane element associated with device  10  (e.g., a conductive housing  12 ) may serve as another pole of the antenna. 
       FIG. 7  shows a cross sectional view of antenna structure  26  and an antenna receptacle in device  10 . The antenna structure of  FIG. 7  is shown in its extended state. In the extended state, coupling structures  36  and  42  may be coupled together and antenna resonating element  48  may be electrically coupled to communications path  24  and circuitry  18  through coupling structures  36  and  42 . 
     Antenna structure  26  may reciprocate along its longitudinal axis  28  to transition between its extended and stowed states. In the  FIG. 7  example, antenna structure  26  is shown in the extended state and may be translated in the leftward direction towards the stowed position. 
     Antenna structure  26  may break away from device  10  in a suitable direction such as direction  40 . The magnetic structures of antenna structure  26  and/or device  10  may be configured such that the magnetic coupling releases before a force applied to push or pull structure  26  from device  10  can cause damage to either structure  26  or device  10 . 
       FIG. 8  shows a cross sectional view of an illustrative rotating antenna structure  26  and an antenna receptacle of device  10 . The antenna structure of  FIG. 8  is shown in its stowed state. In the antenna structure&#39;s stowed state, the antenna structure and device  10  may be configured to have a uniform and clutter-free visual appearance by aligning outer portions of structure  26  with surrounding portions of device  10 . Coupling structures in antenna structure  26  may be configured such that a force acting to move the antenna structure in direction  40  may overcome the magnetic attraction between antenna structure  26  and device  10  before damage occurs to either antenna structure  26  or device  10 . 
     In the  FIG. 8  example, antenna structure  26  may be configured to extend by rotating about an axis (e.g., axis  30 ). Coupling structures  38  and  44  may provide acoustic and/or tactile feedback when the antenna structure moves into or out of its stowed position. For example, when a user rotates the antenna structure towards its stowed position, coupling structures  38  and  44  may magnetically attract each other and pull the antenna structure into its stowed position. 
     Coupling structures  36  and  42  may be configured to allow antenna structure  26  to rotate about an axis centered on the coupling structures (e.g., coupling structures  36  and  42 ). The coupling structures may provide acoustic and/or tactile feedback when the antenna structure is positioned in one or more extended positions or in its stowed position. For example, the antenna structures may have steps at certain intervals. The antenna structure may have a preference to move into and stay in the position of the steps. 
     Coupling structures  36  and  42  may be configured to couple antenna resonating element  48  with communications path  24  and circuitry  18 . The coupling between the antenna resonating element and the communications path only occur when the antenna is deployed (or stowed) or alternatively may be independent of the position of the antenna structure. For example, a rotating antenna resonating element may be coupled to the communications path regardless of whether the antenna structure is in its stowed position, a partially extended position, positioned at a certain steps, or a fully extended position, whereas a reciprocating antenna resonating element may only be coupled to communications path  24  when deployed. 
       FIG. 9  shows a cross sectional view of antenna structure  26  and an antenna receptacle of device  10 . In  FIG. 9 , the antenna structure of  FIG. 8  is shown in a possible extended position. In the antenna structure&#39;s extended state, the antenna structure and device  10  may be configured to create a large separation between antenna resonating element  48  and a ground plane of device  10  (e.g., a metal housing of device  10 ). 
     As shown in  FIG. 9  by lines  40 , antenna structure  26  may break away from device  10  without damaging the antenna structure or the device. Antenna structure  26  may be able to break away from device  10  because it is magnetically coupled to device  10  and the magnetic coupling may be configured to be weak enough to release before damage occurs. 
     In a typical scenario, a user of device  10  may have antenna structure  26  in an extended state while performing wireless communications functions. The antenna structure  26  may have forces acting on it that act to break it away from device  10 . For example, a user may inadvertently hit the protruding antenna structure. Because antenna structure  26  is magnetically coupled to device  10 , the antenna structure may not be damaged and may simply fall off of device  10 . Following the antenna structure&#39;s release from device  10 , the user may simply reattach the antenna structure by placing it in proximity to the corresponding antenna receptacle (e.g., in proximity to a position such as its stowed position, its extended position, or an intermediate position) and allowing the magnetic coupling to reattach antenna structure  26  to device  10 . 
     A cross-sectional view of illustrative coupling structures  36  and  42  is shown in  FIG. 10 . Structure  36  (and it associated components such as ball  52 ) and/or structure  42  may be formed with ferromagnetic or magnetic materials. The structures may be magnetically attracted to each other. Structure  36  may be held fixed in an antenna receptacle of device  10  while structure  42  may be fixed in antenna structure  26  and may generally remain on line  28 . Because structures  36  and  42  may be magnetically coupled, structure  42  may break away from structure  36  without causing damage. 
     In the  FIG. 10  example, structures  36  and  42  may form a ball detent. Ball  52  may be contained in the cylindrical walls of structure  36  by a curved upper portion of structure  36  (e.g., retaining structure  54 ). Ball  52  may be biased against retaining structure  54  by spring  57 . 
     Structure  42  may reciprocate along line  28  as antenna structure  26  transitions between its stowed position and its extended position. As structure  42  becomes aligned with structure  36  (e.g., antenna structure  26  enters its extended position), ball  52  of structure  36  may interact with a recessed portion of structure  42  to provide feedback that structures  36  and  42  have coupled. For example, when structure  42  moves towards a position where it is aligned with structure  36 , ball  52  may be biased by spring  57  into a recessed portion of structure  42 . As the ball moves into the recessed portion of structure  42  there may be an acoustic and/or tactile feedback alerting the user that structures  36  and  42  have coupled. 
     The recessed portion of structure  42  may resist forces acting in the directions of line  28  as the edges of the recessed portion impinge ball  52 . This resistance may provide feedback as a user moves antenna structure  26  out of its extended position. 
     Communications path conductor  24  (e.g., a coaxial cable center conductor) may be coupled to antenna resonating element  48  through structures  36  and  42  (including ball  52  of structure  26 ). Ball  52  may be electrically conductive. For example, ball  52  may be formed entirely from conductive material or may be coated with an electrically conductive coating. Magnetic and ferromagnetic materials may optionally be used in ball  52 . Spring  57  and/or structure  36  may be electrically conductive. Structure  42  may be conductive or may have a conductive portion that is electrically coupled to antenna resonating element  48 . 
     Spring  57  may provide a repulsive biasing force against coupling structure  42  (e.g., antenna  26 ). This repulsive biasing force may be countered by the magnetic attraction of elements  44  and  38 . For example, the magnetic attraction of elements  44  and  38  may be strong enough to hold antenna structure  26  to device  10  even when spring  57  (and ball  52 ) is pushing against structure  42 . 
     Optional magnetic and/or ferromagnetic materials in ball  52  and/or coupling structure  36  and magnetic and/or ferromagnetic materials in coupling structure  42  may provide a magnetic attraction force between coupling structure  36  and/or ball  52  and coupling structure  42 . The magnetic attraction force may be stronger than the biasing force provided by spring  57 . For example, the magnetic attraction force provided by optional magnetic and ferromagnetic materials in ball  52  and/or coupling structures  36  and  42  and the repulsive force spring  57  provides may be configured such that there is a net attractive force between coupling structure  36  and/or ball  52  and coupling structure  42 . 
     A cross-sectional view of another set of illustrative coupling structures  36  and  42  is shown in  FIG. 11 . Structure  36  and/or structure  42  of  FIG. 11  may be formed from ferromagnetic or magnetic materials. The structures may be magnetically attracted to each other. Structure  36  may be held fixed in an antenna receptacle of device  10  while structure  42  may be fixed in antenna structure  26  and may generally remain on line  28 . Because structures  36  and  42  may be magnetically coupled, structure  42  may break away from structure  36  without causing damage. 
     In the  FIG. 11  example, structures  36  and  42  may form a ball detent with no spring. Ball  52  may be formed from ferromagnetic or magnetic materials. In a ball detent with no spring, ball  52  may be biased against retaining structure  54  by a magnetic attraction with structure  42 . In another embodiment, a movable structure within structure  36  such as ball  52  may be biased against retaining structure  54  by a magnetic repulsion with a magnetic portion of structure  36 . The ball detent arrangement of  FIG. 11  may retain all the features of the ball detent of  FIG. 10  with the biasing force of spring  57  replaced by a magnetic attraction or repulsion between ball  52  and structure  42  or structure  36 , respectively. 
     The ball detent arrangements of  FIGS. 10 and 11  may be self-cleaning. For example, as coupling structure  42  moves relative to coupling structure  36 , ball  52  may rotate or otherwise move around inside of coupling structure  36 . The motion of ball  52  may cause the surface of ball  52  to wipe against structure  42 , retaining structure  54 , or a portion of structure  36 . As the surface of ball  52  wipes against another surface, the surface of ball  52  may be cleared of dirt or other debris, thereby helping ball  52  to make good electrical contact with other coupling structures. 
     The ball detent arrangements of  FIGS. 10 and 11  may also distribute wear evenly on ball  52  and allow for better optimization of the ball detent coupling. For example, because ball  52  is relatively free to move around in coupling structure  36 , the wear that occurs during normal operation may be evenly distributed on the surface of ball  52  thereby extending its serviceable lifetime. The distribution of wear evenly on ball  52  may also allow for coatings on ball  52  that are optimized for electrical properties (e.g., resistance) rather than coatings that are optimized for durability. The even distribution of wear on ball  52  may also increase the magnitude of tolerable forces on the ball detent arrangement. 
     Optional sensor  58  may be used to determine the position of ball  52 . The position of ball  52  may be a means of determining the position of structure  26  (i.e., whether structure  42  and structure  36  are coupled and therefore whether antenna structure  26  is in its extended position). Sensor  58  may be coupled to circuitry  18  to control the operation of wireless communications devices  82  or other components in device  10 . 
     Communications path  24  may be coupled to antenna resonating element  48  through structures  36  and  42  (including ball  52 ). Ball  52  may be formed from an electrically conductive material or may be coated with an electrically conductive coating. The walls of structure  36  may also be electrically conductive. Structure  42  may be conductive or may have a conductive portion that is electrically coupled to antenna resonating element  48 . 
     A cross-sectional view of another suitable arrangement for coupling structures  36  and  42  is shown in  FIG. 12 . In the  FIG. 12  embodiment, attraction elements  37  and  43  may provide a magnetic attraction force that couples structures  36  and  42  together. Attraction elements  37  and  43  may made from magnetic or ferromagnetic materials as needed to provide the magnetic attraction force between coupling structures  36  and  42 . For example, element  37  may be made from magnetic materials while element  43  may be made from ferromagnetic materials. Alternatively, both attraction elements may be made from magnetic materials. 
     In the  FIG. 12  example, coupling structure  42  may reciprocate along axis  28  when antenna structure  26  transitions between its extended and stowed positions (i.e., similar to  FIGS. 10 and 11 ). Coupling structures  36  and  42  may provide feedback such as tactical and/or acoustic feedback when antenna structure  26  transitions into or out of its extended position. For example, the user may be able to feel the magnetic attraction and then allow the coupling structures to bring themselves into the correct position via their magnetic attraction. 
     In one embodiment, coupling structure  42  may rotate about axis  30  when antenna structure  26  transitions between its stowed position and its extended positions (i.e., when structure  26  moves in a direction such as direction  370  as shown in  FIG. 5 ). 
     Communications path  24  may be coupled to antenna resonating element  48  through structures  36  and  42 . Structures  36  and  42  or portions of structures  36  and  42  may be electrically conductive. Attraction elements  37  and  43  or portions of attraction elements  37  and  43  may also be electrically conductive. 
     In  FIG. 13 , the illustrative coupling structures of  FIG. 12  have been provided with a protrusion to coupling structure  36  and a corresponding section of structure  42  has been shaped to accommodate the protrusion. Edge  62  outlines the shape of the interface between coupling structures  36  and  42 . 
     When antenna structure  26  is configured to reciprocate along axis  28 , the interface shown in  FIG. 13  may increase the feedback that occurs when antenna structure  26  enters or leaves its extended position. For example, the protrusion of structure  37  may suddenly drop into the recessed portion of structure  42  and create feedback that is more apparent to a user than the  FIG. 12  embodiment. 
     When antenna structure  26  is configured to rotate about axis  30  (i.e., when structure  26  moves in a direction such as direction  370  as shown in  FIG. 5 ), the interface shown in  FIG. 13  may help coupling structure  42  maintain its coupling with structure  36  as the antenna structure is rotated about axis  30 . The interface of  FIG. 13  may limit non-rotational movement between structures  36  and  42 . For example, edge  62  may cause structures  36  and  42  to stay aligned even as non-rotational forces acting to move antenna structure  26  away from axis  30  act upon the coupling structures (e.g., structures  36  and  42 ). 
     In  FIG. 14 , the coupling structures of  FIG. 13  are illustrated in a nearly coupled state that may occur just before or just after antenna structure  26  is in its extended position. There may be a void (e.g., void  63 ) in coupling structure  42  and there may be a corresponding protrusion  64  in coupling structure  36  that align when the antenna structure is in its extended position. 
     Void  63  and protrusion  64  may provide feedback to a user of device  10  when extending antenna structure  26  along line  28  into its extended position. As antenna structure  26  enters its extended position, protrusion  64  may suddenly drop into void  63  and in doing so may create feedback informing the user that the antenna structure is correctly in its extended position. The feedback may be, for example, an audible sound or may be tactile feedback such as antenna structure  26  suddenly shifting into its extended position. 
     In the  FIG. 15  example, an illustrative embodiment of coupling structures  36  and  42  is shown. The coupling structures illustrated by  FIG. 15  may be suitable in antenna structures such as antenna structure  26  that are configured to extend and stow by rotating about an axis such as axis  30  ( FIG. 4 ). 
     Coupling structures  36  and  42  may be configured to have an interface such as interface  66  that is symmetric about the axis of rotation (e.g., axis  30 ). For example, coupling structure  36  may have a cylindrical depression and coupling structure  42  may have a corresponding cylindrical protrusion. The interface may allow structure  42  to freely rotate about axis  30  while limiting the movement of structure  42  in directions perpendicular to axis  30 . 
     Coupling structures  36  and  42  may be configured to provide feedback such as acoustic and/or tactile feedback when antenna structure  26  is in certain positions. For example, as antenna structure  26  and hence coupling structure  42  rotate about axis  30 , structures  36  and  42  may be configured to provide resistance at certain intervals in the rotation of structure  26  around axis  30 . As one possible example of how structures  36  and  42  may provide feedback, coupling structures  36  and  42  may implement a ball detent arrangement using evenly spaced ball receptacles arranged circularly around the protrusion of structure  42  and one or more balls in structure  36  biased to mate with receptacles of structure  42 . 
     With another suitable arrangement, coupling structures  36  and  42  may be non-cylindrical structures that provide positional feedback as antenna  26  is rotated between its retracted position and one or more extended positions. For example, coupling structures  36  and  42  may configured as corresponding coupling structures that have a predominantly square shape that provides detents (e.g., click-stops) every ninety degrees. In general, coupling structures  36  and  42  may be configured with any suitable shape to provide click-stops at any desired interval or position. For example, structures  36  and  42  may be formed in a rectangular shape to provide detents every 180 degrees, a triangular shape to provide detents every 120 degrees, a hexagonal shape to provide detents every 60 degrees, etc. Structures  36  and  42  may also be configured in a non-symmetrical shape that provides click-stops at irregular intervals (such as 0 degrees of extension as well as 90 and 120 degrees of rotational extension). 
     Attraction elements  37  and  43  may be cylindrical disks that may be centered on or near axis  30 . Attraction elements  37  and  43  may be made from ferromagnetic or magnetic materials and may provide a magnetic force that provides a physical coupling force to hold together structures  36  and  42 . Attraction elements  37  and  43  may be configured to provide enough magnetic force to retain antenna structure  26  on device  10  during normal operations while providing a sufficiently weak magnetic force to avoid damage to antenna structure  26  on device  10  under larger than normal stresses or forces (e.g., when a user accidently pushes or pulls antenna structure  26 ). 
       FIG. 16  shows an illustrative embodiment of coupling structures  36  and  42  that may be suitable for antenna structures such as antenna structure  26  that are configured to extend and stow by rotation about an axis such as axis  30 . 
     Coupling structure  36  of  FIG. 16  may have a cylindrical protrusion such as protrusion  68  that may fit into a corresponding cylindrical depression in coupling structure  42 . The mating of the two cylindrical features of the coupling structures may limit the relative movement between the two coupling structures (e.g., structures  36  and  42 ) in directions perpendicular to axis  30  while freely allowing structure  42  to rotate about structure  36  and around an axis of rotation (e.g., axis  30 ). 
     Magnetic attraction elements  37  and  43  may be arranged in circular rings that may be centered on or near axis  30 . Magnetic attraction elements  37  and  43  may be made from ferromagnetic or magnetic materials and may provide a magnetic force that provides a physical coupling force to hold together structures  36  and  42 . Magnetic attraction elements  37  and  43  may be configured to provide enough magnetic force to retain antenna structure  26  on device  10  during normal operations but insufficient magnetic force to create damage to antenna structure  26  on device  10  when a user accidently pushes or pulls antenna structure  26 . 
     The coupling structures of  FIGS. 12 ,  13 ,  14 ,  15 , and  16  (e.g., coupling structures  36  and  42 ) may capacitively couple communications path  24  to antenna resonating element  48 . For example, coupling structures  36  and  42  may not physically connect communications path  24  to antenna resonating element  48 . Structures  36  and  42  may bring portions of path  24  and element  48  into a close physical proximity so that path  24  and element  48  are capacitively coupled together and signals pass between path  24  and element  48  without a direct physical connection. 
     The spring-loaded coupling structures (e.g., from  FIGS. 10 and 11 ) and the attractive coupling structures (e.g., from  FIGS. 12 ,  13 ,  14 ,  15 ,  16 , and  17 ) may help to ensure electrical contact even with manufacturing tolerances. For example, coupling structures such as structures  36  and  42  may allow for manufacturing tolerances that are less restrictive while still ensuring good electrical contact between antennas such as antenna  26  and antenna  27  and electronic devices such as device  10 . 
     A schematic diagram of devices that have circuitry that may be electrically coupled with magnetic coupling structures is shown in  FIG. 17 . A first device such as device  90  may have circuitry  94  and a second device such as device  92  may have may have circuitry  96 . Circuitry  94  and circuitry  96  may be any suitable circuitry. For example, the circuitry may be processing circuitry, sensor circuitry, communications circuitry, storage circuitry, antenna structure circuitry (e.g., an antenna resonating element), input-output circuitry, etc. Device  90  and device  92  may be any suitable devices such as electronic devices, handheld electronic devices, portable electronic devices such as laptop computers, antenna structures such as structure  26 , electronic components, or other suitable devices. 
     Circuitry  94  and circuitry  96  may be electrically coupled through one or more coupling structures  100  in device  90  and one or more corresponding coupling structures  104  in device  92 . Coupling structures  100  and  104  may be formed from magnetic and/or ferromagnetic material so that they are magnetically attracted to each other. Communications paths  98  may carry signals from circuitry  94  to coupling structures  100 . Communications paths  102  may carry signals from circuitry  96  to coupling structures  104 . There may be any suitable number of communications paths and corresponding coupling structures. Communications paths  98  and  102  may carry any suitable signal such as power supply signals, ground signals, analog signals, digital signals, radio-frequency signals, DC signals associated with sensors such as position sensors, etc. If desired, a detection signal may be carried by communications paths  98  and  102  and coupling structures  100  and  104 . The detection signal may indicate when the first device and the second device have magnetically coupled (e.g., physically and electrically). 
     Coupling structures  100  and  104  may be made from ferromagnetic and/or magnetic materials. With one suitable arrangement, coupling structures  100  and  104  are made from magnetic materials. With another suitable arrangement, coupling structures  100  are made from magnetic materials while coupling structures  104  are made from ferromagnetic materials or vice versa. 
     Coupling structures  104  may physically couple device  92  to device  90  by magnetically attracting coupling structures  100 . Coupling structures  104  may also electrically couple communications paths  102  to communications paths  98  (e.g., circuitry  96  to circuitry  94 ) by electrically coupling with coupling structures  100 . Electric coupling between coupling structures  100  and  104  may occur when the coupling structures are physically coupled. For example, the coupling structures may themselves be electrically conductive and may provide an electrical coupling whenever coupling structures  100  are brought into physical contact with coupling structures  104 . The coupling structures may also contain or be associated with suitable electrical coupling structures such as a pin and socket arrangements. As an example, the coupling structures may have a pin and socket arrangement in which structures  100  have electrically conductive pins that spring out and structure  104  have electrically conductive sockets designed to receive the pins. 
     With another suitable arrangement, communications paths  102  and  104  may be capacitively coupled together when coupling structures  100  and  104  are physically coupled. When communications paths  102  and  104  are capacitively coupled together, signals can be conveyed between circuitry  94  and circuitry  96  without a direct physical path between circuitry  94  and circuitry  96 . 
     As shown in  FIG. 18 , antenna structure  26  may have more than one coupling structures with corresponding antenna resonating elements. For example, antenna structure  26  may have a first coupling structure such as coupling structure  42  and a corresponding antenna resonating element such as resonating element  48  and may also have a second coupling structure such as coupling structure  106  and a corresponding antenna resonating element such as resonating element  108 . 
     The antenna structure of  FIG. 18  may have multiple extended positions each of which corresponds to a particular coupling structure of antenna structure  26  (e.g., structure  42  or  106 ) aligning with and coupling to coupling structure  36  of device  10 . For example, as antenna structure  26  is translated towards the stowed position from the position shown in  FIG. 18  along line  28 , coupling structure  106  may align with and couple to coupling structure  36 . 
     The multiple antenna resonating elements of  FIG. 18  may be individually optimized for performance in a particular radio-frequency band. For example, antenna resonating element  48  may be optimized for performance in the 2.4 GHz band that is sometimes used for Wi-Fi® (IEEE 802.11) and Bluetooth® communications while antenna resonating element  108  may be optimized for performance in a 3G data band (e.g., the UMTS band at 1920-2170 MHz). 
     With another suitable arrangement, multiple coupling structures on antenna  26  may be used to couple communications path  24  to antenna resonating element  48  at multiple feed points (e.g., as illustrated by dotted line  200 ). When antenna  26  is in its fully deployed state, communications path  24  may be coupled to the end of element  48  through structures  36  and  42 . When antenna  26  is in its partially deployed stated, communications paths  24  may be coupled to element  48  somewhere along its length (e.g., not at to the end of element  48 ) through structures  36  and  106  (and through path  200 ). Antenna  26  and resonating element  26  may have different resonances based on where path  24  is coupled to element  26 . For example, by moving antenna  26  between one or more partially extended states and the fully extended state and thereby coupling path  24  to different sections of antenna resonating element  26 , a user may configure antenna  26  to operate in one of multiple frequencies. 
       FIG. 19  illustrates that device  10  may have more than one coupling structures that couple to a common resonating element depending the extended position of antenna structure  26 . For example, in a fully-extended position, coupling structure  36  and antenna resonating element  48  may be coupled to coupling structure  36  and a first communications path  24 . In a partially-extended position, coupling structure  110  and antenna resonating element  48  may be coupled to coupling structure  110  and a second communications path  112 . 
     The multiple coupling structures and communications paths of device  10  may provide a user with an opportunity to configure antenna structure  26  or device  10  through a physical interaction with the antenna structure. For example, coupling structure  110  may be configured to convey half the transmission power to antenna resonating element  48  that coupling structure  42  is configured to convey so that a user may choose whether to conserve power or have maximum performance. In another example, coupling structure  110  may coupled to a Wi-Fi radio-frequency transceiver (e.g., 2.4 GHz transceiver) through communications path  112  and coupling structure  36  may be coupled to a 3G data radio-frequency transceiver (e.g., 1920-2170 MHz transceiver) through communications path  24 . 
     As shown in  FIG. 20 , coupling structure  36  may be mounted on a flexible mounting structure such as mounting structure  114 ,  116 , or  118 . Each flexible mounting structure may bias structure  36  in a different direction (or not at all) relative to coupling structure  42 . Each flexible mounting structure may deform to the shape of mounting structure  120  when structures  36  and  42  are coupled. The use of flexible mounting structures such as structure  114 ,  116 , or  118  may help to ensure electrical contact between circuitry  94  and circuitry  96  even if manufacturing tolerances are not strict. 
     Flexible mounting structure  114  may bias structure  36  towards structure  42  when the coupling structures are coupled. The biasing of structure  36  against structure  42  may result from the flexing of mounting structure  114  into the shape of mounting structure  120  and may result in increased electrical conductivity between the coupling structures. 
     Flexible mounting structure  116  may have an approximately neutral biasing force when structures  36  and  42  are coupled. Because the shape of mounting structure  116  is approximately the same as the shape of mounting structure  120 , flexible mounting structure  116  may have a negligible biasing force. 
     Flexible mounting structure  118  may bias structure  36  away from structure  42  when structures  36  and  42  are coupled. The biasing of structure  36  away from structure  42  may result as the flex of mounting structure  118  is straightened into the shape of mounting structure  120 . 
     Flexible mounting structures  114 ,  116 , and  118  may configured to optimize antenna structure  26  and its interaction with device  10 . For example, mounting structure  114  may result in increased electrically conductivity in the electrical path through structures  36  and  42  as the contact force between the two structures is increased. Mounting structure  118  may result in increased tactile feedback when structures  36  and  42  are coupled. Configurations with a mounting structure such as mounting structure  118  may also result in an improved visual appearance of antenna structure  26  as the antenna structure is pulled closer to device  10  by the biasing force of the coupling structures (e.g., by the force of mounting structure  118  attempting to maintain its original shape). 
     As shown in  FIGS. 21 and 22 , the antenna structure (e.g., structure  26 ) of  FIG. 4  does not have to be square. 
     As illustrated by  FIG. 21 , antenna structure  26  and device  10  may have corresponding tapered portions. The taper of antenna  26  and device  10  may help to increase the separation between an antenna resonating element in antenna  26  and a ground plane which may be formed from portions of device  10 . For example, as antenna structure  26  extenda by reciprocating longitudinally along line  28  or by rotating around axis  30 , antenna structure  26  may move away from device  10  at an angle. By extending at an angle, antenna  26  may have increased separation from device  10  as compared to the square antenna structure illustrated in  FIG. 4 . 
     As illustrated by  FIG. 22 , antenna structure  26  and device  10  may have corresponding curved portions that increase the separation between antenna  26  and device  10  when the antenna is in its extended position. For example, when antenna  26  is in its extended position, antenna  26  may extend from device  10  at an angle (e.g. rather than extending in a simple vertical manner). 
     The foregoing is merely illustrative of the principles of this invention and various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention.

Metadata:
Filing Date: 20080402
Publication Date: 20110201
Grant Date: 20110201
Priority Date: 20080402
Inventors: DEGNER BRETT WILLIAM
LIGTENBERG CHRIS
ANDRE BARTLEY K.
KOUGH DOUGLAS BLAKE
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q1/2258", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/088", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/084", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R13/6205", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/084", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/088", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R2201/02", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01R2201/02", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01Q1/2258", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01R13/6205", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 41132776