PATENT DOCUMENT

Publication Number: US-8325094-B2
Application Number: US-48649609-A
Country: US
Kind Code: B2

Title: Dielectric window antennas for electronic devices

Abstract:
Logo antennas are provided for electronic devices such as portable computers. An electronic device may have a housing with conductive housing walls. A logo antenna may be formed from an antenna resonating element such as a patch antenna resonating element, a monopole antenna resonating element, or other antenna resonating element structure. A conductive cavity may be placed behind the antenna resonating element. A dielectric antenna window that serves as a logo may be used to cover the antenna resonating element. The dielectric antenna window may be mounted in an opening in the conductive housing walls. A positive antenna feed terminal may be coupled to the antenna resonating element. A ground antenna feed terminal may be coupled to the cavity and portions of the conductive housing walls. The dielectric antenna window may be shaped in the form of a logo.

Claims:
1. A portable computer with a logo antenna, comprising:
 a lid; 
 a base pivotably connected to the lid; 
 a metal housing wall that forms a top surface for the lid; 
 a dielectric logo structure in the metal housing wall that serves as a dielectric antenna window for the logo antenna; 
 an antenna resonating element for the logo antenna that is mounted behind the dielectric logo structure, so that radio-frequency antenna signals pass from the antenna resonating element through the dielectric logo structure; 
 a ground antenna terminal connected to the metal housing wall. 
 
     
     
       2. The portable computer defined in  claim 1  wherein the dielectric logo structure contains text. 
     
     
       3. The portable computer defined in  claim 2  wherein the dielectric logo structure comprises a planar plastic member. 
     
     
       4. The portable computer defined in  claim 1  wherein the dielectric logo structure comprises a logo-shaped plastic member. 
     
     
       5. The portable computer defined in  claim 1  further comprising a conductive antenna cavity for the logo antenna that is mounted behind the antenna resonating element. 
     
     
       6. The portable computer defined in  claim 5  wherein the antenna resonating element comprises a patch antenna resonating element. 
     
     
       7. A logo antenna, comprising:
 metal antenna ground structures having a ground antenna feed terminal, wherein the metal antenna ground structures comprises metal housing walls in an electronic device; 
 an inverted-F antenna resonating element having first and second arms and having a positive antenna feed terminal; and 
 a logo-shaped dielectric antenna window that covers least part of the antenna resonating element. 
 
     
     
       8. The logo antenna defined in  claim 7  wherein the logo-shaped dielectric antenna window comprises plastic. 
     
     
       9. The logo antenna defined in  claim 7  wherein the metal antenna ground structures include an antenna cavity. 
     
     
       10. The logo antenna defined in  claim 7  wherein:
 a first portion of the metal antenna ground structures comprise the metal housing walls; 
 a second portion of the conductive antenna ground structures comprise a metal antenna cavity; and 
 the inverted-F antenna resonating element is interposed between the metal antenna cavity and the logo-shaped dielectric antenna window. 
 
     
     
       11. The logo antenna defined in  claim 10  wherein the metal antenna cavity comprises a rectangular metal cavity with vertical sidewalls and a planar rear wall structure that lies parallel to the logo-shaped dielectric antenna window.

Description:
BACKGROUND 
     This relates generally to electronic device antennas, and, more particularly, to antennas for electronic devices with conductive housings. 
     Electronic devices such as portable computers and handheld electronic devices are becoming increasingly popular. Devices such as these are often provided with wireless communications capabilities. For example, electronic devices may use long-range wireless communications circuitry such as cellular telephone circuitry to 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). Long-range wireless communications circuitry may also be used handle the 2100 MHz band and other bands. Electronic devices may use short-range wireless communications links to handle communications with nearby equipment. For example, electronic devices may communicate using the WiFi® (IEEE 802.11) bands at 2.4 GHz and 5 GHz (sometimes referred to as local area network bands) and the Bluetooth® band at 2.4 GHz. 
     It can be difficult to incorporate antennas successfully into an electronic device. Some electronic devices are manufactured with small form factors, so space for antennas is limited. Antenna operation can also be blocked by intervening metal structures. This can make it difficult to implement an antenna in an electronic device that contains conductive display structures, conductive housing walls, or other conductive structures that can potentially block radio-frequency signals. 
     It would therefore be desirable to be able to provide improved antennas for wireless electronic devices. 
     SUMMARY 
     Logo antennas are provided for electronic devices. An electronic device such as a portable computer or cellular telephone may be provided with a housing. The housing may contain conductive sidewalls. For example, the housing may be formed from a machined block of aluminum or other metals. The walls of the housing may be used to hold conductive components such as displays. Integrated circuits and other electronic components may be mounted within the housing. 
     A logo antenna may transmit and receive radio-frequency antenna signals through a dielectric window mounted in a housing wall. The logo antenna may have an antenna resonating element structure such as a patch antenna resonating element. The dielectric antenna window may serve as a logo. The dielectric antenna window may, for example, have the shape of a logo or may contain appropriate text or other visual logo attributes. 
     The logo antenna may be provided with a conductive antenna cavity. The cavity may have vertical sidewalls and a planar rear surface or may have other suitable cavity shapes. The antenna resonating element may be interposed between the dielectric antenna window and the antenna cavity. The antenna cavity may help isolate the logo antenna from the electronic components within the housing. With one suitable arrangement, the antenna cavity may be interposed between the antenna resonating element and the display, so that the rear wall of the antenna cavity lies parallel to the exposed planar face of the logo-shaped dielectric antenna window and the display. 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative electronic device with an antenna in accordance with an embodiment of the present invention. 
         FIGS. 2A and 2B  are respective front and rear perspective views of another illustrative electronic device with an antenna in accordance with an embodiment of the present invention. 
         FIG. 3  is a schematic diagram of an illustrative electronic device with antenna structures in accordance with an embodiment of the present invention. 
         FIG. 4  is a top view of an illustrative inverted-F antenna resonating element for a logo antenna in accordance with an embodiment of the present invention. 
         FIG. 5  is a top view of an illustrative monopole antenna resonating element for a logo antenna in accordance with an embodiment of the present invention. 
         FIG. 6  is a top view of an illustrative slot antenna resonating element for a logo antenna in accordance with an embodiment of the present invention. 
         FIG. 7  is a top view of an illustrative patch antenna resonating element for a logo antenna in accordance with an embodiment of the present invention. 
         FIG. 8  is a top view of an illustrative multibranch inverted-F antenna resonating element for a logo antenna in accordance with an embodiment of the present invention. 
         FIG. 9  is a perspective view of an illustrative antenna cavity for a logo antenna in accordance with an embodiment of the present invention. 
         FIG. 10  is a top view of an illustrative circular dielectric antenna window for a logo antenna in accordance with an embodiment of the present invention. 
         FIG. 11  is a top view of an illustrative rectangular dielectric antenna window for a logo antenna in accordance with an embodiment of the present invention. 
         FIG. 12  is a top view of an illustrative logo-shaped dielectric antenna window for a logo antenna in accordance with an embodiment of the present invention. 
         FIG. 13  is a cross-sectional side view of an electronic device such as a portable computer that has a logo antenna in accordance with an embodiment of the present invention. 
         FIG. 14  is a cross-sectional side view of a portion of an electronic device such as a portable computer that has a logo antenna in accordance with an embodiment of the present invention. 
         FIG. 15  is a perspective view of a portion of an electronic device such as a portable computer that has a logo antenna in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices may be provided with wireless communications circuitry. The wireless communications circuitry may be used to support wireless communications in one or more wireless communications bands. Antenna structures in an electronic device may be used in transmitting and receiving radio-frequency signals. The electronic device may have a conductive housing. For example, the electronic device may have a housing in which one or more portions are machined from blocks of aluminum or other metals. The metals may be coated with an insulating coating. For example, aluminum housing walls can be anodized. Electronic devices may also have components such as display screens that serve as relatively large planar conductive members. These components may be mounted within a housing such as a computer lid. 
     It can be difficult to successfully operate an antenna in an electronic device that is enclosed by conductive housing walls and conductive components such as displays. One or more of the housing walls may therefore be provided with a dielectric antenna window. To reduce visual clutter, it may be desirable to hide the antenna window in plain view, by forming the window from a dielectric logo structure. With this type of arrangement, a plastic logo may be mounted in a prominent location on an electronic device housing. Because the logo carries branding information or other information that is of interest to the user of the electronic device, the logo may serve a useful and accepted information-conveying purpose and need not introduce an undesirable visible design element to the exterior of the electronic device. 
     Antenna structures for the electronic device may be located under the plastic logo or other dielectric window. This allows the antenna structures to operate without being blocked by conductive housing walls or conducting components. In this type of configuration in which the antenna structures are blocked from view but can still operate by transmitting and receiving radio-frequency signals through the dielectric, the antenna structures may form antennas of a type that is sometimes referred to as a “logo antenna.” Logo antennas may be used in environments in which other antenna mounting arrangements may be cumbersome, aesthetically unpleasing, or prone to interference due to the proximity of conductive housing walls or other conductive device structures that can block radio-frequency antenna signals. 
     Any suitable electronic devices may be provided with logo antennas. As an example, logo antennas may be formed in electronic devices such as desktop computers, portable computers such as laptop computers and tablet computers, in handheld electronic devices such as cellular telephones, etc. With one suitable configuration, which is sometimes described herein as an example, the logo antennas are formed in the housings of relatively compact electronic devices in which interior space can be valuable. The compact devices may be portable electronic devices. 
     Portable electronic devices that may be provided with logo antennas include laptop computers and small portable computers such as ultraportable computers, netbook computers, and tablet computers. Portable electronic devices may also be somewhat smaller devices. Examples of smaller portable electronic devices that may be provided with logo antennas include wrist-watch devices, pendant devices, headphone and earpiece devices, and other wearable and miniature devices. With one suitable arrangement, the portable electronic devices may be handheld electronic devices such as cellular telephones. 
     Space is at a premium in portable electronic devices and housings for these devices are sometimes constructed from conductive materials that block antenna signals. Arrangements in which antenna structures are formed behind a dielectric window such as a logo-shaped window can help address these challenges. For example, configurations in which a logo is placed in the center of the metal lid of a portable computer may be used. In this type of configuration, the logo antenna may be operated with relatively few obstructions both when the lid is in a closed position and in an open position. At the same time, the aesthetic appeal of the portable computer will not be disturbed, because users are accustomed to the presence of logos in prominent locations such as on computer lids. If the antenna were not located under the logo, the antenna might have to be located in an unobtrusive portion of the device to preserve desired aesthetics. This could compromise antenna operation. 
     Logo antennas can be mounted on any suitable exposed portion of a portable electronic device. For example, logo antennas can be provided on the front or top surface of the device. In a handheld device or other device in which the rear of the device may be exposed during operation, it may be acceptable to mount a logo antenna on the rear device surface. Other configurations are also possible (e.g., with logos mounted in more confined locations, on device sidewalls, etc.). The use of antenna logo mounting locations such as the top or rear surface is sometimes described herein as an example, but, in general, any suitable logo antenna mounting location may be used in an electronic device if desired. 
     Handheld devices that may be provided with logo antennas include cellular telephones, media players with wireless communications capabilities, handheld computers (also sometimes called personal digital assistants), remote controllers, global positioning system (GPS) devices, and handheld gaming devices. Handheld devices and other portable devices may include the functionality of multiple conventional devices. As an example, a handheld device with cellular telephone functions may include computing equipment resources that allow the handheld device to run games, media player applications, web browsers, productivity software, and other code. 
     An illustrative portable device such as a portable computer that may include a logo antenna is shown in  FIG. 1 . As shown in  FIG. 1 , device  10  may be a portable computer having a housing such as housing  12 . Housing  12  may have an upper portion such as upper housing  12 A, which is sometimes referred to as the lid or cover. Housing  12  may also have a lower portion such as lower housing  12 B, which is sometimes referred to as the housing base or main unit. Housing portions  12 A and  12 B may be pivotably attached to each other using a hinge structure such as hinge  32  (sometimes referred to as a clutch barrel hinge). A display may be mounted to the inner surface of upper housing  12 A, as indicated by dashed lines  14 . Other components such as keyboard  36  and touch pad  34  may be mounted in lower housing  12 B. 
     Housing  12 , which is sometimes referred to as a case, may be formed of any suitable materials including, plastic, wood, glass, ceramics, metal, or other suitable materials, or a combination of these materials. In some situations, portions of housing  12  may be a dielectric or other low-conductivity material, so that the operation of conductive antenna elements that are located in proximity to housing  12  are not disrupted. In other situations, housing  12  may be formed from metal elements. An advantage of forming housing  12  from metal or other structurally sound conductive materials is that this may improve device aesthetics and may help improve durability and portability. 
     Particularly in configurations for device  10  in which some or all of housing  12  is formed from conductive materials, it may be advantageous to form an antenna for device  10  using a logo antenna arrangement. With this type of configuration, one or more of the antennas for device  10  may be hidden from view behind a dielectric antenna window that serves as a logo. In the example of  FIG. 1 , device  10  has logo antenna  26  on housing portion  12 A. Logo antennas such as the illustrative logo antenna of  FIG. 1  may be mounted in prominent locations within device  10 , because users of device  10  are accustomed to prominently located logos. With the illustrative prominent mounting location for logo antenna  26  of  FIG. 1 , logo antenna  26  is mounted in a central portion of the exterior surface of upper housing portion  12 A (i.e., in roughly the middle of the top surface of the computer lid). Other mounting locations may be used if desired (e.g., on the side or rear of device  10 , on an interior surface, such as a surface adjacent to keys  36 , etc.). 
     Another illustrative electronic device is shown in  FIGS. 2A and 2B . In the example of  FIGS. 2A and 2B , device  10  is a handheld electronic device such as a handheld device with cellular telephone capabilities. As shown in  FIG. 2A , device  10  may have a housing  12 . Housing  12  may be formed from plastic, metal, other suitable dielectric materials, other suitable conductive materials, or combinations of such materials. A display such as display  14  may be provided on the front face of device  10 . Display  14  of  FIG. 2A  may be a touch screen display (as an example). Device  10  may have a speaker port  40  and other input-output ports. One or more buttons such as button  38  and other user input devices may be used to gather user input. As shown in  FIG. 2B , logo antenna  26  may be provided on rear surface  42  of device  10  (as an example). Housing  12  of device  10  in  FIG. 2B  may be formed from a conductive material or there may be circuit boards and other conductive components in device  10  that block radio-frequency antenna signals. By providing a dielectric window such as a dielectric logo-shaped window associated with logo antenna  26  of  FIG. 2B , logo antenna  26  may operate without being blocked by these conductive structures. 
     A schematic diagram of device  10  showing how device  10  may include one or more logo antennas  26  and transceiver circuits that communicate with logo antennas  26  is shown in  FIG. 3 . Electronic device  10  of  FIG. 3  may be a portable computer such as a laptop computer, a portable tablet computer, a mobile telephone, a mobile telephone with media player capabilities, a handheld computer, a remote control, a game player, a global positioning system (GPS) device, a desktop computer, a combination of such devices, or any other suitable electronic device. 
     As shown in  FIG. 3 , electronic device  10  may include storage and processing circuitry  16 . Storage and processing circuitry  16  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., static or dynamic random-access-memory), etc. Processing circuitry in storage and processing circuitry  16  may be used to control the operation of device  10 . Processing circuitry  16  may be based on a processor such as a microprocessor and other suitable integrated circuits. With one suitable arrangement, storage and processing circuitry  16  may be used to run software on device  10 , such as internet browsing applications, voice-over-internet-protocol (VOIP) telephone call applications, email applications, media playback applications, operating system functions, etc. Storage and processing circuitry  16  may be used in implementing suitable communications protocols. Communications protocols that may be implemented using storage and processing circuitry  16  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 circuitry  14  may be used to allow data to be supplied to device  10  and to allow data to be provided from device  10  to external devices. Input-output devices  18  such as touch screens and other user input interface are examples of input-output circuitry  14 . Input-output devices  18  may also include user input-output devices such as buttons, joysticks, click wheels, scrolling wheels, touch pads, key pads, keyboards, microphones, cameras, etc. A user can control the operation of device  10  by supplying commands through such user input devices. Display and audio devices may be included in devices  18  such as liquid-crystal display (LCD) screens, light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), and other components that present visual information and status data. Display and audio components in input-output devices  18  may also include audio equipment such as speakers and other devices for creating sound. If desired, input-output devices  18  may contain audio-video interface equipment such as jacks and other connectors for external headphones and monitors. 
     Wireless communications circuitry  20  may include radio-frequency (RF) transceiver circuitry  23  formed from one or more integrated circuits, power amplifier circuitry, low-noise input amplifiers, passive RF components, one or more antennas, and other circuitry for handling RF wireless signals. Wireless signals can also be sent using light (e.g., using infrared communications). 
     Wireless communications circuitry  20  may include radio-frequency transceiver circuits for handling multiple radio-frequency communications bands. For example, circuitry  20  may include transceiver circuitry  22  that handles 2.4 GHz and 5 GHz bands for WiFi (IEEE 802.11) communications and the 2.4 GHz Bluetooth communications band. Circuitry  20  may also include cellular telephone transceiver circuitry  24  for handling wireless communications in cellular telephone bands such as the GSM bands at 850 MHz, 900 MHz, 1800 MHz, and 1900 MHz, and the 2100 MHz data band (as examples). Wireless communications circuitry  20  can include circuitry for other short-range and long-range wireless links if desired. For example, wireless communications circuitry  20  may include global positioning system (GPS) receiver equipment, wireless circuitry for receiving radio and television signals, paging circuits, etc. In WiFi and Bluetooth links and other short-range wireless links, wireless signals are typically used to convey data over tens or hundreds of feet. In cellular telephone links and other long-range links, wireless signals are typically used to convey data over thousands of feet or miles. 
     Wireless communications circuitry  20  may include antennas  26 . Some or all of antennas  26  may be logo antennas such as logo antenna  26  of  FIG. 1  and logo antenna  26  of  FIG. 2B . Logo antennas  26  may be single band antennas that each cover a particular desired communications band or may be multiband antennas. A multiband antenna may be used, for example, to cover multiple cellular telephone communications bands. If desired, a dual band logo antenna may be used to cover two WiFi bands (e.g., 2.4 GHz and 5 GHz). Different types of antennas may be used for different bands and combinations of bands. For example, it may be desirable to form a dual band antenna for forming a local wireless link antenna, a multiband antenna for handling cellular telephone communications bands, and a single band antenna for forming a global positioning system antenna (as examples). 
     Paths  44  such as transmission line paths may be used to convey radio-frequency signals between transceivers  22  and  24  and antennas  26 . Radio-frequency transceivers such as radio-frequency transceivers  22  and  24  may be implemented using one or more integrated circuits and associated components (e.g., switching circuits, matching network components such as discrete inductors, capacitors, and resistors, and integrated circuit filter networks, etc.). These devices may be mounted on any suitable mounting structures. With one suitable arrangement, transceiver integrated circuits may be mounted on a printed circuit board. Paths  44  may be used to interconnect the transceiver integrated circuits and other components on the printed circuit board with logo antenna structures in device  10 . Paths  44  may include any suitable conductive pathways over which radio-frequency signals may be conveyed including transmission line path structures such as coaxial cables, microstrip transmission lines, etc. 
     Logo antennas  26  may, in general, be formed using any suitable antenna types. Examples of suitable antenna types for logo antennas  26  include antennas with resonating elements that are formed from patch antenna structures, inverted-F antenna structures, closed and open slot antenna structures, loop antenna structures, monopoles, dipoles, planar inverted-F antenna structures, hybrids of these designs, etc. All or part of a logo antenna may be formed from a conductive portion of housing  12 . For example, housing  12  or a part of housing  12  may serve as a conductive ground plane for a logo antenna. Conductive cavities may be provided for a logo antenna (e.g., to form a cavity-backed antenna design). 
     Illustrative antenna structures that may be used in forming a logo antenna for device  10  include inverted-F antenna structures such as the inverted-F antenna structure of  FIG. 4 . Antenna  26  of  FIG. 4  may be fed by radio-frequency source  52  at positive antenna feed terminal  54  and ground antenna feed terminal  56 . Positive antenna feed terminal  54  may be coupled to antenna resonating element  58 . Ground antenna feed terminal  56  may be coupled to ground element  60 . Resonating element  58  may have a main arm  46  and a shorting branch  48  that connects main arm  46  to ground  60 . 
       FIG. 5  shows an illustrative arrangement for logo antenna  26  that is based on a monopole antenna configuration. In the example of  FIG. 5 , resonating element  58  of antenna  26  has a meandering serpentine path shape. Feed terminal  54  may be connected to one end of resonating element  58 . Ground feed terminal  56  may be coupled to housing  12  or another suitable ground plane element. 
     In the example of  FIG. 6 , conductive antenna structures  62  are configured to define a closed slot  64  and an open slot  66 . The antenna formed from structures  62  of  FIG. 6  may be fed using positive antenna feed terminal  54  and ground antenna feed terminal  56 . In this type of arrangement, slots  64  and  66  serve as antenna resonating elements for antenna  26 . The sizes of slots  64  and  66  may be configured so that antenna  26  operates in desired communications bands (e.g., 2.4 GHz and 5 GHz, etc.). 
     Another possible configuration for logo antenna  26  is shown in  FIG. 7 . In the arrangement of  FIG. 7 , antenna  26  has a patch antenna resonating element  68 . Antenna  26  of  FIG. 7  may be fed using positive antenna feed terminal  54  and ground antenna feed terminal  56 . Ground  60  may be associated with housing  12  or other suitable ground plane elements in device  10 . 
       FIG. 8  shows another illustrative configuration that may be used for the antenna structures of logo antenna  26 . In the  FIG. 8  example, antenna resonating element  58  has two main arms. Arm  46 A is shorter than arm  46 B and is therefore associated with higher frequencies of operation than arm  46 A. By using two or more separate resonating element structures of different sizes, antenna resonating element  58  can be configured to cover a wider bandwidth or more than a single communications band of interest. 
     Antenna resonating elements and other logo antenna structures in device  10  may be formed from any suitable conductive structures. For example, antenna structures can be formed from conductive traces on flexible and rigid printed circuit boards. Rigid printed circuit boards may be formed from a dielectric substrate such as epoxy (e.g., a fiberglass-filled epoxy substrate such as FR4). Flexible printed circuits boards (“flex circuits”) may be formed from polymer films such as polyimide films. Antenna structures may also be formed from conductive layers on plastic support structures, machined or stamped metal parts, metal foil, wires, or other suitable conductive structures. Antenna resonating elements may be formed from structures that are separate from the dielectric antenna window or may be formed as part of the dielectric antenna window (e.g., by forming conductive traces on the underside of the window). When forming antenna resonating elements from separate structures such as printed circuit board structures, the resonating elements may be attached to the dielectric window or other portions of device  10  using adhesive, fasteners, or other suitable mounting structures. 
     If desired, antenna structures of the type shown in  FIGS. 4 ,  5 ,  6 ,  7 , and  8 , and other antenna structures for logo antenna  26  may be backed by a conductive antenna cavity. In a typical cavity antenna configuration, the antenna cavity is grounded and serves to reflect and direct antenna signals away from the cavity. For use with logo antenna  26 , for example, a cavity may be placed beneath the dielectric logo structure and associated antenna resonating element to direct antenna signals through the dielectric logo and into free space. This type of configuration may improve antenna efficiency and may help isolate internal electrical components in device  10  from the antenna, thereby reducing potential electromagnetic interference. 
     An illustrative antenna cavity for logo antenna  26  is shown in  FIG. 9 . In the example of  FIG. 9 , cavity  68  has a substantially rectangular aperture in the exterior surface of conductive structures  74 , conductive vertical sidewalls  70 , and conductive planar lower surface  72 . Conductive cavity structures  74  and the structures that make up cavity surfaces such as walls  70  and  72  can be formed from portions of a conductive housing  12  (e.g., portions of metal housing walls), portions of printed circuit boards, stamped metal parts, metal traces on plastic supports, separately machined metal structures, or any other suitable conductive members. Although the illustrative configuration of cavity  68  of  FIG. 9  is rectangular, antenna cavities such as cavity  68  may, in general, have any suitable shape. For example, a cavity for a cavity-backed logo antenna may have straight sidewalls, curved sidewalls, a planar lower wall surface, a curved lower surface, a circular or oval surface opening, other nonrectangular surface opening shapes, combinations of these feature shapes, or cavity structures of other suitable shapes. 
     A logo antenna may be formed behind a dielectric window of any suitable configuration. As an example, a logo antenna may be formed from a circular dielectric window structure such as dielectric window  76  of  FIG. 10 . 
     As shown by rectangular dielectric window structure  76  of  FIG. 11 , dielectric window structures for logo antenna  26  may be rectangular or may have other non-circular shapes. If desired, structures such as window structure  76  of  FIG. 10  and window structure  76  of  FIG. 11  may be provided with colored regions, text, graphics, surface texture, or other features that allow window structure  76  to convey visual information to a user. This information, which is shown schematically by lines  78  in  FIG. 11 , may include brand name information, promotional text, product information, product type information, or other promotional information. As an example, information  78  may include a company name, a product name, a trademark, a personalized message, or other suitable visual indicator that conveys information of promotional value or other value to a user of device  10 . In a typical scenario, device  10  may be a portable computer, and dielectric window  76  may include information  78  such as the name of the manufacturer of the portable computer. Sometimes logos can convey this information without text or by using a logo shape in combination with text, graphics, colors, etc. In the example of  FIG. 12 , dielectric window  76  is a logo-shaped dielectric window having the trademark shape of a well known manufacturer of computers (Apple Inc. of Cupertino, Calif.). These are merely illustrative examples. Logo antenna  26  may have any suitable dielectric logo structure that serves as a dielectric antenna window. 
     Dielectric window structures such as dielectric window structures  76  of  FIGS. 10 ,  11 , and  12  may be formed over antenna structures such as the structures of  FIGS. 4 ,  5 ,  6 ,  7 , and  8 , with or without cavities of the type shown in  FIG. 9  or other suitable antenna structures. The size of logo structures  76  may be selected to cover some or all of the underlying antenna (i.e., the “footprint” of dielectric window structure  76  may be matched to the underlying antenna size and shape). There need not be a perfect match between the size and shape of dielectric window structure  76  and the underlying antenna structures in a given logo antenna. For example, dielectric window structure  76  may be somewhat larger or somewhat smaller in area than the underlying antenna resonating element structures and/or antenna cavity in logo antenna  26 . 
     Antenna dielectric window structure  76  may be formed from any suitable dielectric that is transparent to radio-frequency signals in the communications bands of interest for logo antenna  26 . For example, antenna dielectric window structure  76  may be formed using plastics such as acrylonitrile butadiene styrene (ABS) plastic, polycarbonate, epoxy, polyimide, other suitable polymer materials, ceramic, glass, wood, structures that incorporate small amounts of conductive materials into a dielectric (e.g., for visual impact), etc. 
     A cross-sectional side view of an illustrative electronic device with a logo antenna is shown in  FIG. 13 . Electronic device  10  of  FIG. 13  may be, for example, a portable computer. As shown in  FIG. 13 , electronic device  10  may have an upper housing  12 A and a lower housing  12 B. Upper housing  12 A and lower housing  12 B may be pivotably connected by hinge  32 . If desired, device  10  may be a tablet computer without hinged housing portions. The example of  FIG. 13  is merely illustrative. 
     Upper housing  12 A may have a metal housing wall  80  that covers the top surface of the lid for electronic device  10 . Housing walls for device  10  may be formed from machined aluminum, other metals, other conductive materials, etc. Display  82  may be mounted to the front portion of upper housing  12 A. Display  82  may be, for example, a liquid crystal display (LCD). Display  82  may contain electrodes and other conductive structures that cause display  82  to act as a planar conductive member. Display  82  and housing wall  88  may therefore block passage of radio-frequency antenna signals. 
     Logo antenna  26  may include an antenna resonating element such as antenna resonating elements  58  of  FIGS. 4 ,  5 ,  6 ,  7 , and  8  or other suitable antenna resonating element structures. Dielectric window  76  is transparent to radio-frequency signals and may therefore allow radio-frequency signals  84  to be received by antenna  26  from external sources and to be transmitted by antenna  26  to external sources. Portions of conductive housing wall  80  and other conductive structures in device  10  may be connected to antenna ground feed terminal  56  and may serve as antenna ground for antenna  26 . Positive antenna feed terminal  54  and ground antenna feed terminal  56  may be coupled to a radio-frequency transceiver circuit such as radio-frequency transceiver circuitry  23  in lower housing portion  12 B using transmission line  44  (e.g., a coaxial cable, a flex circuit transmission line, etc.). Radio-frequency transceiver circuitry  23  may be mounted on one or more printed circuit boards in housing  12 B such as printed circuit board  86 . 
     A cross-sectional side view of an illustrative configuration for a cavity-backed logo antenna is shown in  FIG. 14 . As shown in  FIG. 14 , logo antenna  26  may have a dielectric logo window  76  and antenna resonating element  58 . Antenna ground structures for antenna  26  may be formed from portions of conductive housing wall  80  in upper housing  12 A. These structures or other suitable ground structures may be shorted to antenna cavity  68 . Cavity  68  may, for example, be a metal rectangular cavity of the type shown in  FIG. 9 . Housing portion  12 A may be used to mount display  82  and other electrical components for device  10  (shown schematically as electrical components  90 ). Potential electromagnetic interference between logo antenna  26  and components  90  and  82  may be reduced by the presence of antenna cavity  68 . Antenna cavity  68  may also help to improve the efficiency of logo antenna  26 . 
     A perspective view of an illustrative logo antenna in an electronic device is shown in  FIG. 15 . As shown in  FIG. 15 , electronic device  10  may have housing structures such as conductive housing wall  80 . Dielectric window  76  (which is circular in the  FIG. 15  example) may be disposed over antenna resonating element  58  (e.g., a rectangular patch antenna in this example) to cover element  58  from view. Antenna  26  may be fed using antenna feed terminals  54  and  56 . Portions of housing wall  80  may serve as antenna ground and may, with antenna cavity  68 , be shorted to antenna ground feed terminal  56 . 
     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: 20090617
Publication Date: 20121204
Grant Date: 20121204
Priority Date: 20090617
Inventors: AYALA VAZQUEZ ENRIQUE
SPRINGER GREGORY A.
CHIANG BING
KOUGH DOUGLAS B.
SCHLUB ROBERT W.
JIANG YI
GOMEZ ANGULO RODNEY ANDRES
CABALLERO RUBEN
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q13/18", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/2258", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q13/18", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/2258", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 43353847