PATENT DOCUMENT

Publication Number: US-8264412-B2
Application Number: US-14274408-A
Country: US
Kind Code: B2

Title: Antennas and antenna carrier structures for electronic devices

Abstract:
Antenna support structures and antennas are provided for wireless electronic devices such as portable electronic devices. Antenna resonating elements may be formed from conductive coatings on two-shot molded interconnect device dielectric antenna support structures. The conductive coatings may be formed from wet-plated copper or other conductive materials. The antenna support structure may have tabs that electrically connect antenna resonating elements to the case of a wireless electronic device that serves as an antenna ground plane. The antenna support structure may be curved about its longitudinal axis so that the antenna resonating elements on the support structure protrude upwards to enhance antenna performance. In a portable electronic device such as a portable computer, the antenna support structure may be mounted within a dielectric portion of the computer housing that is located between the display portion of the housing and the base of the housing.

Claims:
1. A laptop computer antenna, comprising:
 a molded interconnect device dielectric antenna support structure; 
 a conductive coating on the molded interconnect device dielectric antenna support structure that defines at least one antenna resonating element for the antenna; and 
 a conductive case that serves as an antenna ground plane for the antenna, wherein the at least one antenna resonating element comprises at least three antenna resonating elements on the molded interconnect device dielectric antenna support structure each of which forms a separate antenna with the antenna ground plane, wherein at least two of the separate antennas are multiband antennas. 
 
     
     
       2. The laptop computer antenna defined in  claim 1  wherein the molded interconnect device dielectric antenna support structure comprises a two-shot molded interconnect device antenna support structure having a portion that is coated with plated metal that forms the antenna resonating element. 
     
     
       3. The laptop computer antenna defined in  claim 1  wherein the conductive case comprises a portable computer base housing that has a top surface that lies in a plane and wherein the molded interconnect device dielectric antenna support structure and at least part of the antenna resonating element protrude above the plane. 
     
     
       4. The laptop computer antenna defined in  claim 1  wherein the molded interconnect device dielectric antenna support structure comprises a plurality of tabs each of which has a hole, wherein the tabs are coated with conductor that is electrically connected to the antenna resonating element. 
     
     
       5. The laptop computer antenna defined in  claim 1  wherein the molded interconnect device dielectric antenna support structure comprises a plurality of tabs that are coated with conductor and that are electrically connected to the antenna ground plane, the portable computer further comprising:
 a transmission line that carries antenna signals; and 
 a conductive clip that grounds a ground conductor in the transmission line to the tabs. 
 
     
     
       6. An electronic device comprising:
 a conductive base housing that forms an antenna ground plane; 
 a two-shot molded interconnect device dielectric antenna support structure having at least one antenna resonating element, wherein the antenna resonating element and the antenna ground plane form an antenna; and 
 a transmission line that feeds the antenna, wherein the at least one antenna resonating element comprises at least three antenna resonating elements and wherein at least two of the antenna resonating elements form multiband antennas with the antenna ground plane. 
 
     
     
       7. The electronic device defined in  claim 6  wherein the molded interconnect device dielectric antenna support structure has metal-coated tabs with holes that are electrically connected to the antenna resonating element, the electronic device further comprising a metal clip that electrically connects the transmission line to the antenna resonating element at the tabs, wherein the antenna resonating element comprises a via to which a center conductor associated with the transmission line is connected to form a positive antenna feed terminal for the antenna. 
     
     
       8. A laptop computer, comprising:
 a conductive base housing that forms an antenna ground plane; 
 a display housing that is connected to the conductive base housing with hinges; 
 a dielectric housing portion that is located between the conductive base housing and the display housing and that is rigidly attached to the conductive base housing; 
 a dielectric antenna support structure that is mounted within the dielectric housing portion; and 
 at least one antenna resonating element on the dielectric antenna support structure, wherein the antenna resonating element and the antenna ground plane form an antenna for the laptop computer. 
 
     
     
       9. The laptop defined in  claim 8  wherein the dielectric antenna support structure comprises a two-shot molded interconnect device dielectric antenna support structure having a portion that is coated with conductor that forms the antenna resonating element. 
     
     
       10. The laptop computer defined in  claim 8  comprising at least two antenna resonating elements on the dielectric antenna support structure each of which forms a separate antenna with the antenna ground plane. 
     
     
       11. The laptop computer defined in  claim 8  comprising at least three antenna resonating elements on the dielectric antenna support structure each of which forms a separate antenna with the antenna ground plane, wherein at least two of the antenna resonating elements are configured to operate in two communications bands. 
     
     
       12. The laptop computer defined in  claim 8  comprising at least three antenna resonating elements on the dielectric antenna support structure each of which forms a separate antenna with the antenna ground plane, wherein at least two of the antenna resonating elements are configured to operate at 2.4 GHz and 5.0 GHz communications bands. 
     
     
       13. The laptop computer defined in  claim 8  wherein the dielectric antenna support structure comprises a curved surface on which the antenna resonating element is formed. 
     
     
       14. The laptop computer defined in  claim 8  wherein the conductive base housing has a top surface that lies in a plane and wherein the dielectric antenna support structure protrudes above the plane. 
     
     
       15. The laptop computer defined in  claim 8  wherein the dielectric antenna support structure comprises a plurality of tabs that are coated with conductor and that are electrically connected to the antenna ground plane, the laptop computer further comprising:
 a transmission line that carries antenna signals; and 
 a metal clip that is crimped to a ground conductor in the transmission line and that electrically connects the ground conductor to the tabs. 
 
     
     
       16. The laptop computer define in  claim 8  wherein the dielectric antenna support structure comprises a plurality of tabs that are coated with conductor that is electrically connected to the dielectric antenna resonating element and that is electrically connected to the antenna ground plane using screws. 
     
     
       17. The laptop computer defined in  claim 8  wherein the conductive base housing comprises a top case and a bottom case, wherein the top case has a plurality of tabs, wherein the dielectric antenna support structure comprises a plurality of tabs that are coated with conductor that is electrically connected to the antenna resonating element, and wherein the tabs of the dielectric antenna support structure are connected to the tabs of the top case using screws. 
     
     
       18. The laptop computer define in  claim 8  wherein the conductive base housing comprises a top case and a bottom case, wherein the top case has a plurality of tabs, wherein the dielectric antenna support structure comprises a plurality of tabs that are coated with conductor that is electrically connected to the antenna resonating element, wherein the tabs of the dielectric antenna support structure are connected to the tabs of the top case using screws, wherein the conductive base housing has a top surface that lies in a plane, and wherein the dielectric antenna support structure protrudes above the plane.

Description:
This patent application claims the benefit of provisional patent application No. 61/019,218, filed Jan. 4, 2008, which is hereby incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     This invention relates to antennas, and more particularly, to antenna structures and antennas for electronic devices. 
     Many modern electronic devices use antennas. For example, portable electronic devices are often provided with wireless communications capabilities. Portable electronic devices may use wireless communications to communicate with wireless base stations. As an example, cellular telephones may communicate using cellular telephone bands at 850 MHz, 900 MHz, 1800 MHz, and 1900 MHz (e.g., the main Global System for Mobile Communications or GSM cellular telephone bands). Portable electronic devices may also use other types of communications links. For example, portable 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. Communications are also possible in data service bands such as the 3G data communications band at 2100 MHz band (commonly referred to as UMTS or Universal Mobile Telecommunications System). 
     To satisfy consumer demand for portable wireless devices, manufacturers are continually striving to reduce the size of components that are used in these devices. For example, manufacturers have made attempts to miniaturize the antennas used in portable electronic devices. 
     A typical antenna may be fabricated by patterning a metal layer on a circuit board substrate or may be formed from a sheet of thin metal using a foil stamping process. These techniques can be used to produce antennas that fit within the tight confines of a portable device. With conventional portable electronic devices, however, design compromises are made to accommodate compact antennas. These design compromises may include, for example, compromises related to antenna efficiency and antenna bandwidth. 
     It would therefore be desirable to be able to provide improved antenna structures for electronic devices such as portable electronic devices. 
     SUMMARY 
     Wireless communications structures for computers or other electronic devices are provided. The wireless communications structures may include antennas and antenna support structures for antennas. 
     A portable electronic device such as a portable computer may have a base housing formed from a top case and bottom case. The base housing may be conductive and may serve as an antenna ground plane. 
     A display housing portion may be mounted to the base housing using hinges. A dielectric housing portion that is rigidly connected to the base housing may be located between the base housing and the display housing. A two-shot molded interconnect device dielectric antenna support structure may be mounted within the dielectric housing portion. Three antenna resonating elements may be formed on the antenna support structure. 
     The antenna resonating elements on the antenna support structure and the antenna ground plane may form three separate antennas for the portable computer. Metal clips may be used to ground transmission lines to tabs associated with the antenna resonating elements. The antenna resonating elements may be connected to the ground plane using screws or other suitable fasteners. 
     The top case may have a top surface that lies in a plane. The dielectric antenna support structure may have a curved surface on which the antenna resonating elements are formed. The curved surface may protrude above the plane, thereby elevating the antenna resonating element so that the antenna performs well without interference from adjacent metal components. 
     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 such as a portable electronic device in accordance with an embodiment of the present invention. 
         FIG. 2  is a schematic diagram of an illustrative electronic device in accordance with an embodiment of the present invention. 
         FIG. 3  is a diagram of illustrative antennas and radio-frequency transceiver circuitry in accordance with an embodiment of the present invention. 
         FIG. 4  is a perspective view of an illustrative set of antenna resonating elements supported by an antenna carrier in accordance with an embodiment of the present invention. 
         FIG. 5  is a schematic top view of an illustrative antenna in accordance with an embodiment of the present invention. 
         FIGS. 6-8  are illustrative patterns that may be used for antenna resonating elements in accordance with an embodiment of the present invention. 
         FIG. 9  is a perspective view of an antenna structure and an underside portion of a top of a base housing in accordance with an embodiment of the present invention. 
         FIG. 10  is a cross-sectional side view of an antenna carrier and associated antenna resonating element mounted on the antenna carrier in accordance with an embodiment of the present invention. 
         FIG. 11  is a cross-sectional side view of an antenna showing how a coaxial cable may be used to feed the antenna in accordance with an embodiment of the present invention. 
         FIG. 12  is an exploded perspective view of a portion of an antenna resonating element formed on an antenna carrier and an associated grounding clip that may be used to electrically connect a ground conductor of a transmission line such as a coaxial cable to the base of the antenna resonating element in accordance with an embodiment of the present invention. 
         FIG. 13  is a cross-sectional side view of an illustrative portion of an antenna showing how the antenna resonating element of the antenna may protrude above a plane defined by an upper surface of a base portion of a portable computer or other electronic device in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention relates generally to electronic devices, and more particularly, to 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, tablet computers, or small portable computers of the type that are sometimes referred to as ultraportables. Portable electronic devices may also be somewhat smaller devices. Examples of smaller portable electronic devices include wrist-watch devices, pendant devices, headphone and earpiece devices, and other wearable and miniature devices. With one suitable arrangement, 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 portable 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). Two or more multiband antennas of this type may be used in an antenna diversity arrangement. Antenna arrangements with three or more antennas may also be used. For example, device  10  may have two dual-band Wi-Fi antennas and a Bluetooth antenna (as an example). 
     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 combination of these materials. In some situations, portions of housing  12  may be formed from a dielectric or other low-conductivity material, so as not to disturb the operation of conductive antenna elements that are located in proximity to housing  12 . 
     In general, however, housing  12  will be partly or entirely 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-resistant surface. If desired, other metals can be used for the housing of device  10 , such as stainless steel, magnesium, titanium, alloys of these metals and other metals, etc. In scenarios in which housing  12  is formed from conductive elements, one or more of the conductive 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 structure (e.g., a printed circuit board structure used in forming antenna structures for device  10 ). 
     As shown in  FIG. 1 , housing  12  may have a base portion  12 E that is formed from two housing portions  12 A and  12 B. Portion  12 A may sometimes be referred to as a top case. Portion  12 B may sometimes be referred to as a bottom case. If desired, internal frames may be mounted within housing  12  (e.g., within base portion  12 E of housing  12 ). These internal frames may be used for mounting electronic components such as a battery, printed circuit boards containing integrated circuits and other electrical devices, etc. If desired, printed circuit boards (e.g., a motherboard and other printed circuit boards) and other components may be mounted directly to housing  12 . For example, a motherboard may be attached to top case  12 A using screws or other fasteners. Upper portion  12 C of housing  12  may include a frame  12 D that is used to connect a liquid crystal diode (LCD) display  16  or other suitable display into the upper lid (housing) of device  10 . Portion  12 C may be referred to as the display of device  10  or may be referred to a display housing, a display housing portion, etc. 
     Display housing portion  12 C may be attached to housing base  12 E (i.e., the portion of housing  12  that is formed from top case  12 A and bottom case  12 B) using hinges such as hinges  24 . 
     Housing portion  25  may be located at the rear edge of base  12 E between base  12 E and display housing  12 C. Hinges  24  and housing portion  25  of housing base  12 E may have longitudinal axes that are aligned along longitudinal axis  28 . 
     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 . Buttons  14  may form a keyboard on a laptop computer (as an example). 
     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  26 . 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. Transmission lines such as coaxial transmission lines and microstrip transmission lines may be used to convey radio-frequency signals between transceiver circuitry and antenna structures in device  10 . As shown in  FIG. 1 , for example, one or more transmission line such as transmission line  22  may be used to convey signals between antenna structure  20  and circuitry  18 . Transmission line  22  may be, for example, a coaxial cable that is connected between an RF transceiver (sometimes called a radio) and an antenna. Antenna structures such as antenna structure  20  may be located within housing portion  25  at the rear edge of housing base  12 E (i.e., at the juncture between display housing portion  12 C and housing base  12 E) or may be located in other suitable locations. 
     A schematic diagram of an embodiment of an illustrative electronic device such as a portable electronic device is shown in  FIG. 2 . Device  10  may be a desktop computer, a notebook 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 wireless device such as a portable or handheld electronic device. 
     As shown in  FIG. 2 , device  10  may include storage  34 . Storage  34  may include one or more different types of storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory), volatile memory (e.g., battery-based static or dynamic random-access-memory), etc. 
     Processing circuitry  36  may be used to control the operation of device  10 . Processing circuitry  36  may be based on a processor such as a microprocessor and other suitable integrated circuits. With one suitable arrangement, processing circuitry  36  and storage  34  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. Processing circuitry  36  and storage  34  may be used in implementing suitable communications protocols. Communications protocols that may be implemented using processing circuitry  36  and storage  34  include internet protocols, wireless local area network protocols (e.g., IEEE 802.11 protocols—sometimes referred to as 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  38  may be used to allow data to be supplied to device  10  and to allow data to be provided from device  10  to external devices. Display screen  16 , keys  14 , and touchpad  26  of  FIG. 1  are examples of input-output devices  38 . 
     Input-output devices  38  may include user input-output devices  40  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 through user input devices  40 . 
     Display and audio devices  42  may include liquid-crystal display (LCD) screens or other screens, light-emitting diodes (LEDs), and other components that present visual information and status data. Display and audio devices  42  may also include audio equipment such as speakers and other devices for creating sound. Display and audio devices  42  may contain audio-video interface equipment such as jacks and other connectors for external headphones and monitors. 
     Wireless communications devices  44  may include communications circuitry such as radio-frequency (RF) transceiver circuitry formed from one or more integrated circuits, power amplifier circuitry, passive RF components, one or more antennas (e.g., antenna structures such as antenna structure  20  of  FIG. 1 ), and other circuitry for handling RF wireless signals. Wireless signals can also be sent using light (e.g., using infrared communications). 
     Device  10  can communicate with external devices such as accessories  46  and computing equipment  48 , as shown by paths  50 . Paths  50  may include wired and wireless paths. Accessories  46  may include headphones (e.g., a wireless cellular headset or audio headphones) and audio-video equipment (e.g., wireless speakers, a game controller, or other equipment that receives and plays audio and video content). 
     Computing equipment  48  may be any suitable computer. With one suitable arrangement, computing equipment  48  is a computer that has an associated wireless access point 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 portable 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  44  may be used to cover communications frequency bands such as the cellular telephone bands at 850 MHz, 900 MHz, 1800 MHz, and 1900 MHz, data service bands such as the 3G data communications band at 2100 MHz band (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. Device  10  can cover these communications bands and/or other suitable communications bands with proper configuration of the antenna structures in wireless communications circuitry  44 . 
     Antenna structures such as antenna structure  20  of  FIG. 1  may be located at any suitable location in device  10 . In configurations in which device  10  has conductive portions (e.g., conductive sidewalls), it may be advantageous to located antenna structure  20  at a position in which antenna structure  20  is not shielded by conductors. This allows the antennas of device  10  to operate freely without being blocked by the conductive portions of device  10 . 
     With one particularly suitable arrangement, which is described herein as an example, antenna structure  20  is located in housing portion  25  of housing base  12 E. The remainder of housing base  12 E may be formed from top case  12 A and bottom case  12 B. Top case  12 A and bottom case  12 B may be formed from aluminum or other conductive materials. If antenna structures  20  were located within such conductive structures, proper antenna operation would be disrupted due to the electromagnetic shielding effects of the conductive sidewalls of base  12 E. 
     With an arrangement of the type shown in  FIG. 1  in which housing portion  25  is located between base  12 E and display housing portion  12 C, housing portion  25  may be formed from a dielectric. Typical dielectrics include glass, ceramic, rubber, and plastic. These are merely illustrative housing materials for housing portion  25 . Any suitable materials may be used for housing portion  25  if desired. 
     By locating antenna structure  20  within a dielectric housing portion such as portion  25 , the antenna resonating elements of device  10  are located at a sufficient distance from the metals and other conductive materials of housing base  12 E and display housing portion  12 D to ensure that the antennas in device  10  function properly. An advantage of locating antenna structure  20  and dielectric housing portion  25  on a portion of base housing  12 E is that this helps to minimize the length of the transmission lines that are used to convey signals between radio-frequency transceiver circuitry (e.g., circuitry  18  of  FIG. 1 ) and antenna structure  20 , thereby helping to reduce signal losses. Arrangements of the type shown in  FIG. 1  also help to avoid the need to pass radio-frequency transmission lines through a hinged portion of device  10  where they would be subject to twisting movement and possible mechanical failure. 
       FIG. 3  shows a top view of an illustrative antenna structure  20  and portions of an associated device  10 . As shown in  FIG. 3 , wireless communications devices  44  may include three antennas, each of which is formed from a respective antenna resonating element such as one of antenna resonating elements  56  and a common ground plane such as ground plane  54 . Ground plane  54  may be formed from conductive structures associated with base  12 E (i.e., top case  12 A and the conductive structures mounted to and electrically connected to top case  12 A). Antenna resonating elements  56  may be mounted on support structure  64  and may be formed from any suitable structures such as substantially planar conductive patterns of the type that are sometimes referred to as planar inverted-F antenna resonating elements or inverted-F antenna resonating elements. 
     As shown in  FIG. 3 , each antenna may be fed using a positive signal conductor (center conductor)  65  in a respective transmission line  62  that is connected to a respective positive antenna terminal  58  and a ground signal conductor in that transmission line  62  that is connected to a respective ground antenna terminal  60 . If desired, matching networks may be used at the antenna feeds to help match the impedance of transmission lines paths  62  to the impedance of each antenna, to match a balanced transmission line to an unbalanced antenna, to match an unbalanced transmission line to a balanced antenna, etc. Tuning components may also be connected to the antennas (e.g., to portions of antenna resonating elements  58 ) to help tune the performance of the antennas. In the configuration of  FIG. 3  in which antenna resonating elements are used with ground plane  54  to form inverted-F antennas that are fed using terminals  58  and  60 , the antennas that are formed function as shunt-fed monopole antennas. 
     Radio-frequency transceiver circuitry  52  may include switches or passive signal combiners and dividers that allow one or more radio-frequency transmitters and receivers (sometimes referred to as radios) to be coupled to the antennas formed from antenna resonating elements  56 . In the example of  FIG. 3 , there are three transmission lines  62  connected to radio-frequency transceiver circuitry  52  and three associated antennas in devices  44  each of which is formed from a respective antenna resonating element  56  and common ground plane  54 . Antenna structure  20  of  FIG. 3  may be formed in housing portion  25 . Ground plane  54  may be formed from housing base  12 E (e.g., housing portion  12 A and/or  12 B). In general, there may be any suitable number of antennas (one or more) in housing portion  25 . The example of  FIG. 3  is merely illustrative. 
     In the illustrative configuration of  FIG. 3 , the leftmost antenna and the rightmost antenna may be used to handle Wi-Fi signals (e.g., in the 2.4 GHz and 5.0 GHz bands). These two antennas may be used to implement an antenna diversity scheme. The center antenna of  FIG. 3  may be used to handle Bluetooth® signals at 2.4 GHz or may be used to handle Wi-Fi communications at 2.4 GHz or 5.0 GHz (e.g., in a diversity scheme working in conjunction with the leftmost and rightmost antennas). In these illustrative arrangements, the antennas are multiband antennas or (in the case of a single-band Bluetooth antenna) a single band antenna. If desired, the antennas of antenna structure  20  may all be single band antennas, may all be multi-band antennas, or may include both single-band and multi-band antennas. 
     Antenna resonating elements  56  may be mounted on any suitable mounting structure. With one suitable arrangement, which is sometimes described herein as an example, antenna resonating elements  56  are formed from conductive traces on a dielectric support structure. As shown in  FIG. 4 , for example, antenna resonating elements  56  may be formed on a dielectric support structure such as dielectric support structure  64 . The dielectric material of structure  64  may be a plastic. The dielectric support structure on which the antenna resonating elements are formed is sometimes referred to as an antenna carrier. A dielectric support structure such as structure  64  may be formed from one or more individual dielectric members. For ease of handing and to reduce complexity, it may be advantageous to use a single support member in forming support structure  64 . 
     Support structure  64  may have a longitudinal axis that is aligned with longitudinal axis  28 . In device  10 , support structure  64  and resonating elements  56  may be mounted within housing portion  25  ( FIG. 1 ). When mounted within device  10 , edge  68  of support  64  may be aligned with the outermost edge of device  10 , whereas edge  66  of support  64  and resonating elements  56  may be connected to ground plane  54  (e.g., a housing portion such as base  12 E or, in particular, top case  12 A). Screws or other suitable fasteners may be used to connect antenna resonating elements  56  to the ground plane (e.g., to the conductive housing). Antenna support structure  64  may be configured to form tabs  70  each of which has an associated screw hole  72  through which a screw or other fastener may be passed when affixing antenna support structure  64  and antenna resonating elements  56  to the ground plane formed by base  12 E of housing  12 . 
     As shown in the illustrative configuration of  FIG. 5 , antenna resonating elements  56  may be formed from conductive traces such as trace  74 . Antenna resonating element  56  may be electrically and mechanically attached to ground plane  54  by using screws or other fasteners in holes  72  to attach support  64  to housing portion  12 A at edge  66 . 
     The meandering conductive trace shape shown in the illustrative antenna resonating element  56  of  FIG. 5  is merely illustrative. Antenna resonating elements  56  may have any suitable shape. 
     In general, the shape that is chosen for each antenna resonating element  56  may be determined based on the desired operating frequencies for the antennas of device  10 . For example, in a dual-band antenna arrangement, it may be desirable to configure the shape of the antenna&#39;s resonating element  56  so that the antenna&#39;s fundamental operating frequency corresponds to a first frequency band of interest (e.g., 2.4 GHz) and so that the antenna&#39;s second harmonic operating frequency corresponds to a second frequency band of interest (e.g., 5.0 GHz). The antenna resonating element&#39;s length may be adjusted to be approximately equal to a quarter of a wavelength at the fundamental frequency. Bends, notches, protruding stubs, and other features may be incorporated into a given antenna resonating element to adjust its resonant frequencies and its bandwidth in each band of interest. As an example, folded shapes may be incorporated into the antenna resonating element. The folded shapes may help an antenna designer optimize antenna performance in situations in which it is desired to modify the frequency of the second harmonic resonance without significantly affecting the location of the fundamental antenna resonance. This is because folds may add reactances that affect the harmonic resonance more than the fundamental resonance. If desired, the length of an antenna fold may be adjusted to correspond to an additional secondary resonance that is configured to resonate in band. 
     When selecting a layout for a given antenna resonating element, it is also generally desirable to take into account the influence of structures that enclose the antenna resonating element (e.g., nearby conductive structures such as housing walls). The impact of nearby conductive structures can affect the frequency response of an antenna resonating element. An antenna resonating element will typically perform differently when mounted inside of an enclosure as opposed to being mounted in an unenclosed arrangement. This is because a given antenna resonating element will tend to excite resonances in its enclosure that are tuned via the antenna resonating element. 
     These techniques or other suitable techniques may be used to select a shape for an antenna resonating element that satisfies design goals (e.g., frequency band coverage, efficiency, etc.). 
     Examples of suitable patterns that may be used for the three antenna resonating elements  56  of  FIG. 4  are shown respectively in  FIGS. 6 ,  7 , and  8 . An advantage of using multiple tabs  72  along the edge of each antenna resonating element (e.g., three tabs  72  as in the examples of  FIGS. 6 ,  7 , and  8 ) is that this helps to promote formation of a low resistance path between the antenna resonating element and housing portion  12 E. 
     A perspective view of the underside of an illustrative support structure  64  and top case  12 A showing how support structure  64  and antenna resonating element  56  may be electrically and mechanically connected to top case  12 A is shown in  FIG. 9 . As shown in  FIG. 9 , top case  12 A may have tabs  78  with holes  80  that are aligned with corresponding tabs  70  and holes  72  on support structure  64 . Screws  76  or other suitable fasteners may pass through holes  72  and  80 . Nuts or threads in holes  80  may be used to secure screws  76 . 
     A cross-sectional side view of an illustrative portion of antenna structure  20  is shown in  FIG. 10 . As shown in  FIG. 10 , antenna resonating elements such as antenna resonating element  56  may be formed from a conductive layer on dielectric support structure  64 . Conductive layer portion  86  may coat dielectric portions of support structure  64  that are configured to form tabs  70 . Conductive layer portions  84  may form substantially planar portions of resonating element  56  (e.g., using patterns of the types shown in  FIGS. 6 ,  7 , and  8 ). These substantially planar portions of antenna resonating element  56  may be curved along the arc defined by the semi-circular cross-sectional shape of antenna support structure  64 , as shown in  FIG. 10 . In the vicinity of positive antenna feed terminal  56 , via  82  may be formed through support structure  64 . The conductive layer of antenna resonating element  56  may have portions  88  that coat the inner sidewalls of via  82 , thereby ensuring that molten solder will flow through via  82  when soldering center conductor  65  ( FIG. 5 ) to antenna terminal  58  on the concave underside of antenna support structure  64 . 
     Any suitable technique may be used to form conductive structures for antenna resonating element  56 . For example, conductive structures for antenna resonating element  56  may be formed from stamped metal foil, flexible printed circuit board structures (e.g., polyimide-based structures of the type that are sometimes referred to as flex circuits), etc. With one suitable arrangement, antenna support structure  64  may be formed using a molded interconnect device (MID) manufacturing process such as a two-shot molded interconnect device process. 
     In a two-shot MID process, a plastic may be formulated to repel or attract conductive coatings by selective incorporation of chemical additives. When a first set of additives is incorporated into the plastic, the resulting formulation will attract conductive coatings. When a second set of additives is incorporated into the plastic, the plastic will repel conductive coatings. The different coating behaviors of these two types of plastic allow patterns to be defined for an antenna resonating element (i.e., by patterning the attractive plastic appropriately). An example of a conductive coating that may be used for coating portions of antenna support structure  64  is wet-plated copper. Other suitable coating materials include gold, chrome, nickel, tin, other suitable metals, alloys of these metals, etc. These materials may be deposited using electrochemical deposition (e.g., wet plating techniques) or other suitable techniques. 
     With a two-shot process, portions of antenna support structure  64  that are to be maintained free of conductor may be constructed from a first “shot” using a plastic blend that repels copper (or other conductor). Portions of MID antenna support structure  64  on which antenna resonating elements  56  are to be formed are constructed from a second “shot” using a plastic blend that attracts copper (or other conductor). During a subsequent plating process, only those portions of antenna support structure that were formed from the copper-attracting blend of plastic will be plated with copper. Portions of the antenna support structure that were formed from the copper-repelling blend of plastic will remain uncoated. 
     In the example of  FIG. 10 , the portions of antenna support structure  64  beneath the conductive layers that form antenna resonating element  56  are formed from a plastic blend that attracts copper (or other conductor), whereas the portions of antenna support structure  64  that are not covered by antenna resonating element  56  are formed from a plastic blend that repeals copper (or other conductor). 
     The two portions of the antenna support structure (i.e., the portion to be coated by conductor and the portion that remains uncoated) may be formed using separate MID tool pieces called cavities. In a two-shot process, two cavities are used. In general, any suitable number of shots may be used in forming antenna support structure  64 . The use of a two-shot process is merely illustrative. 
     If desired, other techniques may be used for forming antenna support structures such as support structure  64 . For example, a plastic having portions that are selectively activated by exposure to laser light may be used in forming the antenna support structure. The plastic may be, for example, a thermoplastic that has a organo-metallic additive that is sensitive to light at the wavelengths produced by a laser. The antenna resonating element pattern may be imposed on the plastic of the support structure by exposing the plastic to laser light only in areas in which conductive antenna structures are desired. After exposing desired portions of the plastic to laser light to activate those portions, the plastic may be plated with a suitable conductor such as copper. During plating operations, the laser-activated portions of the plastic attract the plating conductor (e.g., copper), thereby forming conductive antenna resonating element  56 . Techniques in which laser light is used to imprint a desired plating pattern on a plastic support are sometimes referred to as laser direct structuring (LDS) techniques. Laser direct structuring services for forming molded interconnect devices in this way are available from LPKF Laser &amp; Electronics AG of Garbsen, Germany. 
     In general, antenna resonating element structures may be formed on any suitable support structure. The foregoing examples, in which conductive antenna resonating element structures are formed by coating plastic support structures with patterns of metal (e.g., by plating) are merely illustrative. 
     A cross-sectional view of a portion of device  10  in the vicinity of housing portion  25  is shown in  FIG. 11 . As shown in  FIG. 11 , a coaxial cable or other suitable transmission line  62  may be used to feed the antenna formed from antenna resonating element  56  and the ground plane provided by housing portion  12 A. Cable  62  may have an insulating jacket  96 , a conductive braid that serves as ground conductor  94 , dielectric core  92 , and center conductor  65 . At positive antenna feed terminal  58 , the tip of center conductor  65  may be electrically connected to the portions of antenna resonating element  56  that coat the interior of via  82  using solder  90 . Ground conductor  94  may be electrically connected to tab  70  at ground antenna terminal  60 . 
     Any suitable attachment mechanism may be used when attaching ground conductor  94  of transmission line  62  to the portion of electrical conductor on tab  70 . As an example, ground conductor  94  may be connected to tab  70  using solder, fasteners (e.g., screws), welding, etc. 
     As shown in  FIG. 12 , a conductive structure such as clip  98  may be used to help electrically connect ground conductor  94  of transmission line  62  to tabs  70  on antenna support structure  64 . Clip  98  may have holes  100  that are aligned with corresponding holes  72  on tabs  70 . Clip  98  may be formed from any suitable conductor such as sheet metal. An example of a sheet metal that may be used for clip  98  is tin-plated cold rolled steel. Crimped portion  102  of clip  98  may be used to mechanically hold transmission line  62  in place. 
     As shown in the cross-sectional view of  FIG. 13 , antenna support structure  64  may curve sufficiently to allow at least some of antenna resonating element  56  to protrude upwards from the top surface of base  12 E. Top case portion  12 A of housing  12  may have an upper surface that is aligned with plane  104 . Display housing portion  12 C may rotate about rotational axis  106  when the lid of device  10  is opened and closed. Plane  104  may, if desired, be located above rotational axis  106 . At least in region  108 , antenna resonating element  56  lies above plane  104  (and rotational axis  106 ). In this position, antenna resonating element  56  protrudes outwards from device  10  and away from housing surface  12 A and the conductive portions of display housing portion  12 C. Because antenna resonating element  56  protrudes away from the conductive housing structures of device  10 , antenna resonating element  56  may exhibit good performance (e.g., by maintaining line-of-sight communications with wireless equipment such as accessories  46  and computing equipment  48  of  FIG. 2 ). 
     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: 20080619
Publication Date: 20120911
Grant Date: 20120911
Priority Date: 20080104
Inventors: AYALA ENRIQUE
SPRINGER GREGORY ALLEN
KOUGH DOUGLAS B.
MCDONALD MATTHEW IAN
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q9/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/2266", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q9/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/2266", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 40844164