PATENT DOCUMENT

Publication Number: US-9728858-B2
Application Number: US-201414260800-A
Country: US
Kind Code: B2

Title: Electronic devices with hybrid antennas

Abstract:
An electronic device may be provided with hybrid planar inverted-F slot antennas and indirectly fed slot antennas. A hybrid antenna may be used to form a dual band wireless local area network antenna. An indirectly fed slot antenna may be use to form a cellular telephone antenna. Antenna slots may be formed in a metal electronic device housing wall. The housing wall may have a planar rear portion and sidewall portions that extend upwards from the planar rear portion. The slots may have one or more bends. A hybrid antenna may have a slot antenna portion and a planar inverted-F antenna portion. The planar inverted-F antenna portion may have a metal resonating element patch that is supported by a support structure. The support structure may be a plastic speaker box containing a speaker driver that is not overlapped by the metal resonating element patch.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a housing having a metal wall; 
 a hybrid planar inverted-F slot antenna, wherein the hybrid planar inverted-F slot antenna has slot antenna structures formed from a slot in the metal wall and has planar inverted-F antenna structures, the planar inverted-F antenna structures include a ground feed terminal, a positive feed terminal, and a return path leg, the return path leg and the ground feed terminal are coupled to the metal wall on first and second opposing sides of the slot respectively, the positive feed terminal is coupled to the planar inverted-F antenna structures at the second side of the slot, and the positive feed terminal is separated from the metal wall of the housing by a gap; 
 an indirectly fed slot antenna; and transceiver circuitry coupled to both the hybrid planar inverted-F slot antenna and the indirectly fed slot antenna. 
 
     
     
       2. The electronic device defined in  claim 1  wherein the planar inverted-F antenna structures include a resonating element formed from a metal patch. 
     
     
       3. The electronic device defined in  claim 2  further comprising a plastic structure that supports the metal patch. 
     
     
       4. The electronic device defined in  claim 3  wherein the plastic structure forms plastic walls for a speaker box. 
     
     
       5. The electronic device defined in  claim 1  wherein the slot has at least one bend. 
     
     
       6. The electronic device defined in  claim 1  wherein the metal wall has a planar rear wall portion and sidewall portions and the slot is an open slot formed at least partly in the planar rear wall portion and at least partly in the sidewall portions. 
     
     
       7. The electronic device defined in  claim 6  further comprising plastic that fills the slot. 
     
     
       8. A hybrid planar inverted-F slot antenna, comprising:
 slot antenna structures formed from a slot in a metal electronic device housing wall; 
 planar inverted-F antenna structures formed from a metal resonating element, the metal resonating element comprising a feed leg and a return path leg; and 
 a speaker box that supports the metal resonating element, the return path leg and the feed leg being formed on different sides of the speaker box. 
 
     
     
       9. The hybrid planar inverted-F slot antenna defined in  claim 8  wherein the metal electronic device housing wall includes a planar wall portion and wherein the metal resonating element lies in a plane that is parallel to the planar wall portion. 
     
     
       10. The hybrid planar inverted-F slot antenna defined in  claim 9  wherein the slot has at least one bend and has a portion that extends along at least one sidewall portion of the metal electronic device housing wall. 
     
     
       11. The hybrid planar inverted-F slot antenna defined in  claim 8  wherein the slot antenna structures are configured to exhibit an antenna resonance at 2.4 GHz and the planar inverted-F antenna structures are configured to exhibit an antenna resonance at 5 GHz. 
     
     
       12. An electronic device, comprising:
 a hybrid planar inverted-F slot antenna having slot antenna structures formed from a slot in a metal electronic device housing wall and having planar inverted-F antenna structures formed from a metal resonating element and a feed leg that is coupled to the metal resonating element and separated from the metal electronic device housing wall by a gap; and 
 an indirectly fed slot antenna that is indirectly fed using a metal patch structure that is separate from the metal resonating element. 
 
     
     
       13. The electronic device defined in  claim 12  wherein the hybrid planar inverted-F slot antenna comprises a dual band wireless local area network antenna. 
     
     
       14. The electronic device defined in  claim 13  wherein the indirectly fed slot antenna comprises a cellular telephone antenna having a slot formed in the metal electronic device housing wall. 
     
     
       15. The electronic device defined in  claim 1  wherein the planar inverted-F antenna structures include a planar resonating element formed above the slot antenna structures. 
     
     
       16. The electronic device defined in  claim 12 , further comprising:
 a display cover layer, wherein the metal electronic device housing wall comprises a rear housing wall that opposes the display cover layer, the slot comprises a first portion formed in the rear housing wall and a second portion formed in a metal electronic device housing side wall, the second portion extends from the first portion to an edge of the metal electronic device housing side wall, the indirectly fed slot antenna comprises an additional slot having a third portion that is formed in the rear housing wall and a fourth portion that is formed in the metal electronic device housing side wall, and the fourth portion extends from the third portion of the additional slot to the edge of the metal electronic device housing side wall. 
 
     
     
       17. The electronic device defined in  claim 16 , wherein the first portion of the slot comprises a perpendicular bend and a closed end that is surrounded on three sides by the rear housing wall, the third portion of the additional slot comprises a perpendicular bend and a closed end that is surrounded on three sides by the rear housing wall, and the closed end of the first portion of the slot is interposed between the perpendicular bend of the first portion of the slot and the closed end of the third portion of the additional slot. 
     
     
       18. The electronic device defined in  claim 5 , wherein the at least one bend separates the slot into first and second substantially perpendicular portions. 
     
     
       19. The hybrid inverted-F slot antenna defined in  claim 8 , wherein the return path leg is coupled to the metal electronic device housing wall on a first side of the slot and the feed leg is provided directly over a second side of the slot separated from the first side of the slot by the slot. 
     
     
       20. The electronic device defined in  claim 12 , wherein the planar inverted-F antenna structures are further formed from a return path leg coupled to the metal resonating element and the metal electronic device housing wall, the slot comprises a portion that extends to an edge of the metal electronic device housing wall, and the feed leg and the return path are disposed over opposing sides of the portion of the slot.

Description:
BACKGROUND 
     This relates generally to electronic devices and, more particularly, to electronic devices with antennas. 
     Electronic devices often include antennas. For example, cellular telephones, computers, and other devices often contain antennas for supporting wireless communications. 
     It can be challenging to form electronic device antenna structures with desired attributes. In some wireless devices, the presence of conductive housing structures can influence antenna performance. Antenna performance may not be satisfactory if the housing structures are not configured properly and interfere with antenna operation. Device size can also affect performance. It can be difficult to achieve desired performance levels in a compact device, particularly when the compact device has conductive housing structures. 
     It would therefore be desirable to be able to provide improved wireless circuitry for electronic devices such as electronic devices that include conductive housing structures. 
     SUMMARY 
     An electronic device may be provided with wireless circuitry. The wireless circuitry may include radio-frequency transceiver circuitry and one or more antennas. Antennas for the electronic device may be formed from hybrid planar inverted-F slot antenna structures and indirectly fed slot antennas. 
     A hybrid antenna may be used to form a dual band wireless local area network antenna. An indirectly fed slot antenna may be use to form a cellular telephone antenna. Arrays of multiple hybrid antennas may also be formed. 
     A hybrid antenna may have a slot antenna portion and a planar inverted-F antenna portion. The planar inverted-F antenna portion may have a metal resonating element patch that is supported by a support structure. The support structure may be a plastic speaker box containing a speaker driver that is not overlapped by the metal resonating element patch. 
     Antenna slots for the antennas in the electronic device may be formed in a metal electronic device housing wall. The housing wall may have a planar rear portion and sidewall portions that extend upwards from the planar rear portion. The slots may have one or more bends and may be filled with plastic. Slots may also be formed in metal traces on a printed circuit or other metal structures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative electronic device such as a laptop computer in accordance with an embodiment. 
         FIG. 2  is a perspective view of an illustrative electronic device such as a handheld electronic device in accordance with an embodiment. 
         FIG. 3  is a perspective view of an illustrative electronic device such as a tablet computer in accordance with an embodiment. 
         FIG. 4  is a perspective view of an illustrative electronic device such as a display for a computer or television in accordance with an embodiment. 
         FIG. 5  is a schematic diagram of illustrative circuitry in an electronic device in accordance with an embodiment. 
         FIG. 6  is a schematic diagram of illustrative wireless circuitry in accordance with an embodiment. 
         FIG. 7  is a diagram of an illustrative inverted-F antenna structure in accordance with an embodiment. 
         FIG. 8  is a perspective view of an illustrative planar inverted-F antenna structure in accordance with an embodiment. 
         FIG. 9  is a top view of an illustrative closed slot antenna structure in accordance with an embodiment. 
         FIG. 10  is a top view of an illustrative open slot antenna structure in accordance with an embodiment. 
         FIG. 11  is a perspective view of an illustrative hybrid planar inverted-F slot antenna in accordance with an embodiment. 
         FIG. 12  is a graph in which antenna performance (standing wave ratio) has been plotted against operating frequency for an illustrative hybrid planar inverted-F slot antenna in accordance with an embodiment. 
         FIG. 13  is a perspective view of another illustrative hybrid planar inverted-F slot antenna in accordance with an embodiment. 
         FIG. 14  is a perspective view of a portion of an electronic device with multiple antennas in accordance with an embodiment. 
         FIG. 15  is a cross-sectional side view of an illustrative speaker box in accordance with an embodiment. 
         FIG. 16  is a perspective view of an illustrative end portion of an electronic device in which antenna structures for a hybrid antenna are being supported by a speaker box of the type shown in  FIG. 15  in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices may be provided with antennas. The antennas may include slot antenna structures and/or other antenna structures such as inverted-F antenna structures (e.g., planar inverted-F antenna structures). Hybrid antennas and indirectly fed antennas may be formed. For example, a hybrid planar inverted-F slot antenna may be formed by incorporating both planar inverted-F antenna structures and slot antenna structures into an antenna. Slots for antennas can be formed in device structures such as electronic device housing structures. Illustrative electronic devices that have housings that accommodate slot antenna structures, hybrid antennas, and other wireless circuitry are shown in  FIGS. 1, 2, 3, and 4 . 
     Electronic device  10  of  FIG. 1  has the shape of a laptop computer and has upper housing  12 A and lower housing  12 B with components such as keyboard  16  and touchpad  18 . Device  10  has hinge structures  20  (sometimes referred to as a clutch barrel) to allow upper housing  12 A to rotate in directions  22  about rotational axis  24  relative to lower housing  12 B. Display  14  is mounted in housing  12 A. Upper housing  12 A, which may sometimes be referred to as a display housing or lid, is placed in a closed position by rotating upper housing  12 A towards lower housing  12 B about rotational axis  24 . 
       FIG. 2  shows an illustrative configuration for electronic device  10  based on a handheld device such as a cellular telephone, music player, gaming device, navigation unit, or other compact device. In this type of configuration for device  10 , device  10  has opposing front and rear surfaces. The rear surface of device  10  may be formed from a planar portion of housing  12 . Display  14  forms the front surface of device  10 . Display  14  may have an outermost layer that includes openings for components such as button  26  and speaker port  27 . 
     In the example of  FIG. 3 , electronic device  10  is a tablet computer. In electronic device  10  of  FIG. 3 , device  10  has opposing planar front and rear surfaces. The rear surface of device  10  is formed from a planar rear wall portion of housing  12 . Curved or planar sidewalls may run around the periphery of the planar rear wall and may extend vertically upwards. Display  14  is mounted on the front surface of device  10  in housing  12 . As shown in  FIG. 3 , display  14  has an outermost layer with an opening to accommodate button  26 . 
       FIG. 4  shows an illustrative configuration for electronic device  10  in which device  10  is a computer display, a computer that has an integrated computer display, or a television. Display  14  is mounted on a front face of device  10  in housing  12 . With this type of arrangement, housing  12  for device  10  may be mounted on a wall or may have an optional structure such as support stand  30  to support device  10  on a flat surface such as a tabletop or desk. 
     An electronic device such as electronic device  10  of  FIGS. 1, 2, 3, and 4 , may, in general, be a computing device such as a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wrist-watch device, a pendant device, a headphone or earpiece device, or other wearable or miniature device, a television, a computer display that does not contain an embedded computer, a gaming device, a navigation device, an embedded system such as a system in which electronic equipment with a display is mounted in a kiosk or automobile, equipment that implements the functionality of two or more of these devices, or other electronic equipment. The examples of  FIGS. 1, 2, 3, and 4  are merely illustrative. 
     Device  10  may include a display such as display  14 . Display  14  may be mounted in housing  12 . Housing  12 , which may sometimes be referred to as an enclosure or case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of any two or more of these materials. Housing  12  may be formed using a unibody configuration in which some or all of housing  12  is machined or molded as a single structure or may be formed using multiple structures (e.g., an internal frame structure, one or more structures that form exterior housing surfaces, etc.). 
     Display  14  may be a touch screen display that incorporates a layer of conductive capacitive touch sensor electrodes or other touch sensor components (e.g., resistive touch sensor components, acoustic touch sensor components, force-based touch sensor components, light-based touch sensor components, etc.) or may be a display that is not touch-sensitive. Capacitive touch screen electrodes may be formed from an array of indium tin oxide pads or other transparent conductive structures. 
     Display  14  may include an array of display pixels formed from liquid crystal display (LCD) components, an array of electrophoretic display pixels, an array of plasma display pixels, an array of organic light-emitting diode display pixels, an array of electrowetting display pixels, or display pixels based on other display technologies. 
     Display  14  may be protected using a display cover layer such as a layer of transparent glass or clear plastic. Openings may be formed in the display cover layer. For example, an opening may be formed in the display cover layer to accommodate a button, an opening may be formed in the display cover layer to accommodate a speaker port, etc. 
     Housing  12  may be formed from conductive materials and/or insulating materials. In configurations in which housing  12  is formed from plastic or other dielectric materials, antenna signals can pass through housing  12 . Antennas in this type of configuration can be mounted behind a portion of housing  12 . In configurations in which housing  12  is formed from a conductive material (e.g., metal), it may be desirable to provide one or more radio-transparent antenna windows in openings in the housing. As an example, a metal housing may have openings that are filled with plastic antenna windows. Antennas may be mounted behind the antenna windows and may transmit and/or receive antenna signals through the antenna windows. 
     A schematic diagram showing illustrative components that may be used in device  10  is shown in  FIG. 5 . As shown in  FIG. 5 , device  10  may include control circuitry such as storage and processing circuitry  28 . Storage and processing circuitry  28  may include storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid state drive), volatile memory (e.g., static or dynamic random-access-memory), etc. Processing circuitry in storage and processing circuitry  28  may be used to control the operation of device  10 . This processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, application specific integrated circuits, etc. 
     Storage and processing circuitry  28  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. To support interactions with external equipment, storage and processing circuitry  28  may be used in implementing communications protocols. Communications protocols that may be implemented using storage and processing circuitry  28  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, cellular telephone protocols, MIMO protocols, antenna diversity protocols, etc. 
     Input-output circuitry  44  may include input-output devices  32 . Input-output devices  32  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  32  may include user interface devices, data port devices, and other input-output components. For example, input-output devices may include touch screens, displays without touch sensor capabilities, buttons, joysticks, click wheels, scrolling wheels, touch pads, key pads, keyboards, microphones, cameras, buttons, speakers, status indicators, light sources, audio jacks and other audio port components, digital data port devices, light sensors, motion sensors (accelerometers), capacitance sensors, proximity sensors, etc. 
     Input-output circuitry  44  may include wireless communications circuitry  34  for communicating wirelessly with external equipment. Wireless communications circuitry  34  may include radio-frequency (RF) transceiver circuitry formed from one or more integrated circuits, power amplifier circuitry, low-noise input amplifiers, passive RF components, one or more antennas, transmission lines, and other circuitry for handling RF wireless signals. Wireless signals can also be sent using light (e.g., using infrared communications). 
     Wireless communications circuitry  34  may include radio-frequency transceiver circuitry  90  for handling various radio-frequency communications bands. For example, circuitry  34  may include transceiver circuitry  36 ,  38 , and  42 . Transceiver circuitry  36  may be wireless local area network transceiver circuitry that may handle 2.4 GHz and 5 GHz bands for WiFi® (IEEE 802.11) communications and that may handle the 2.4 GHz Bluetooth® communications band. Circuitry  34  may use cellular telephone transceiver circuitry  38  for handling wireless communications in frequency ranges such as a low communications band from 700 to 960 MHz, a midband from 1710 to 2170 MHz, and a high band from 2300 to 2700 MHz or other communications bands between 700 MHz and 2700 MHz or other suitable frequencies (as examples). Circuitry  38  may handle voice data and non-voice data. Wireless communications circuitry  34  can include circuitry for other short-range and long-range wireless links if desired. For example, wireless communications circuitry  34  may include 60 GHz transceiver circuitry, circuitry for receiving television and radio signals, paging system transceivers, near field communications (NFC) circuitry, etc. Wireless communications circuitry  34  may include satellite navigation system circuitry such as global positioning system (GPS) receiver circuitry  42  for receiving GPS signals at 1575 MHz or for handling other satellite positioning data. 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  34  may include antennas  40 . Antennas  40  may be formed using any suitable antenna types. For example, antennas  40  may include antennas with resonating elements that are formed from loop antenna structures, patch antenna structures, inverted-F antenna structures, slot antenna structures, planar inverted-F antenna structures, helical antenna structures, hybrids of these designs, etc. Different types of antennas may be used for different bands and combinations of bands. For example, one type of antenna may be used in forming a local wireless link antenna and another type of antenna may be used in forming a remote wireless link antenna. 
     As shown in  FIG. 6 , transceiver circuitry  90  in wireless circuitry  34  may be coupled to antenna structures  40  using paths such as path  92 . Wireless circuitry  34  may be coupled to control circuitry  28 . Control circuitry  28  may be coupled to input-output devices  32 . Input-output devices  32  may supply output from device  10  and may receive input from sources that are external to device  10 . 
     To provide antenna structures  40  with the ability to cover communications frequencies of interest, antenna structures  40  may be provided with circuitry such as filter circuitry (e.g., one or more passive filters and/or one or more tunable filter circuits). Discrete components such as capacitors, inductors, and resistors may be incorporated into the filter circuitry. Capacitive structures, inductive structures, and resistive structures may also be formed from patterned metal structures (e.g., part of an antenna). If desired, antenna structures  40  may be provided with adjustable circuits such as tunable components  102  to tune antennas over communications bands of interest. Tunable components  102  may include tunable inductors, tunable capacitors, or other tunable components. Tunable components such as these may be based on switches and networks of fixed components, distributed metal structures that produce associated distributed capacitances and inductances, variable solid state devices for producing variable capacitance and inductance values, tunable filters, or other suitable tunable structures. 
     During operation of device  10 , control circuitry  28  may issue control signals on one or more paths such as path  103  that adjust inductance values, capacitance values, or other parameters associated with tunable components  102 , thereby tuning antenna structures  40  to cover desired communications bands. 
     Path  92  may include one or more transmission lines. As an example, signal path  92  of  FIG. 6  may be a transmission line having a positive signal conductor such as line  94  and a ground signal conductor such as line  96 . Lines  94  and  96  may form parts of a coaxial cable or a microstrip transmission line (as examples). A matching network formed from components such as inductors, resistors, and capacitors may be used in matching the impedance of antenna structures  40  to the impedance of transmission line  92 . Matching network components may be provided as discrete components (e.g., surface mount technology components) or may be formed from housing structures, printed circuit board structures, traces on plastic supports, etc. Components such as these may also be used in forming filter circuitry in antenna structures  40 . 
     Transmission line  92  may be directly coupled to an antenna resonating element and ground for antenna  40  or may be coupled to near-field-coupled antenna feed structures that are used in indirectly feeding a resonating element for antenna  40 . As an example, antenna structures  40  may form an inverted-F antenna, a slot antenna, a hybrid inverted-F slot antenna or other antenna having an antenna feed with a positive antenna feed terminal such as terminal  98  and a ground antenna feed terminal such as ground antenna feed terminal  100 . Positive transmission line conductor  94  may be coupled to positive antenna feed terminal  98  and ground transmission line conductor  96  may be coupled to ground antenna feed terminal  92 . As another example, antenna structures  40  may include an antenna resonating element such as a slot antenna resonating element or other element that is indirectly fed using near-field coupling. In a near-field coupling arrangement, transmission line  92  is coupled to a near-field-coupled antenna feed structure that is used to indirectly feed antenna structures such as an antenna slot or other element through near-field electromagnetic coupling. 
     Antennas  40  may include hybrid antennas formed both from inverted-F antenna structures (e.g., planar inverted-F antenna structures) and slot antenna structures. 
     An illustrative inverted-F antenna structure is shown in  FIG. 7 . Inverted-F antenna structure  140  of  FIG. 7  has antenna resonating element  106  and antenna ground (ground plane)  104 . Antenna resonating element  106  may have a main resonating element arm such as arm  108 . The length of arm  108  may be selected so that antenna structure  140  resonates at desired operating frequencies. For example, if the length of arm  108  may be a quarter of a wavelength at a desired operating frequency for antenna  40 . Antenna structure  140  may also exhibit resonances at harmonic frequencies. 
     Main resonating element arm  108  may be coupled to ground  104  by return path  110 . Antenna feed  112  may include positive antenna feed terminal  98  and ground antenna feed terminal  100  and may run in parallel to return path  110  between arm  108  and ground  104 . If desired, inverted-F antenna structures such as illustrative antenna structure  140  of  FIG. 7  may have more than one resonating arm branch (e.g., to create multiple frequency resonances to support operations in multiple communications bands) or may have other antenna structures (e.g., parasitic antenna resonating elements, tunable components to support antenna tuning, etc.). A planar inverted-F antenna (PIFA) may be formed by implementing arm  108  using planar structures (e.g., a planar metal structure such as a metal patch or strip of metal that extends into the page of  FIG. 7 ). 
       FIG. 8  is a perspective view of an illustrative planar inverted-F antenna structure. As shown in  FIG. 8 , planar inverted-F antenna structures  140  have an antenna feed such as feed  112  that includes a downwardly protruding feed leg such as leg  142 . Positive antenna feed terminal  98  may be coupled to leg  142 . Ground antenna feed terminal  100  may be coupled to ground  104  and may be separated from terminal  98  by distance D. Return path (short circuit path)  100  is formed from leg  110  and couples planar resonating element “arm” structure  108  (e.g., a metal patch) to ground plane  104 . Structure  108  is preferably planar and lies in a plane that is parallel to the plane of ground  104 . Structure  108  may have a rectangular plate (patch) shape with lateral dimensions D 1  and D 2  (as an example). Configurations in which structure  108  has a meandering arm shape, shapes with multiple branches, or other shapes may also be used for planar inverted-F antenna structures  140 . Planar inverted-F antenna structures such as structures  140  of  FIG. 8  may be used in a hybrid planar inverted-F slot antenna. 
     Illustrative slot antenna structures of the type that may be used in forming antennas  40  in device  10  are shown in  FIGS. 9 and 10 . 
     Slot antenna structures  144  of  FIG. 9  have a closed slot. As shown in  FIG. 9 , slot  146  is formed from an opening in ground plane  104  and is bridged by antenna feed terminals  98  and  100 . Slot  146  has an elongated shape (e.g., a rectangular shape) with respective ends  148  and  150 . End  148  of slot  146  is surrounded by portions of ground plane  104  (e.g., end  148  of slot  146  is enclosed by metal). End  150  of slot  146  is also surrounded by portions of ground plane  104 . Because both ends of slot  146  are enclosed by metal, slot  146  is surrounded by metal in ground plane  104 . Slots such as illustrative slot  146  of  FIG. 9  that have two closed ends are sometimes referred to closed slots (i.e., antenna structures  144  are closed slot antenna structures). Slot  146  may be filled with air, plastic, and/or other dielectric and may have one or more bends. 
     Slot antenna structures  144  of  FIG. 10  have an open slot. As shown in  FIG. 10 , slot  146  is formed from an opening in ground plane  104  and is bridged by antenna feed terminals  98  and  100 . Slot  146  of  FIG. 10  may be filled with air, plastic, and/or other dielectric and may have one or more bends. 
     Slot  146  of  FIG. 10  has an elongated shape (e.g., a rectangular shape) with respective ends  148  and  150 . End  148  of slot  146  is surrounded by portions of ground plane  104  (e.g., end  148  of slot  146  is enclosed by metal) and is therefore sometimes referred to as forming a closed slot end. End  150  of slot  146  is not surrounded by portions of ground plane  104 , but rather is open to surrounding air and/or other dielectric. Ends such as end  150  may sometimes be referred to as open slot ends. Slots such as slot  146  that have one closed end (end  148 ) and one open end (end  150 ) are sometimes referred to as open slots (i.e., slot antenna structures  144  of  FIG. 10  are open slot antenna structures). The length of an open slot antenna may be about half of the length of a closed slot antenna when being configured to operate at a given frequency, so open slot antennas may sometimes be preferred in compact electronic devices or devices in which it is otherwise desirable to minimize slot length. 
     If desired, slots  146  for antenna structures  144  may have other shapes. For example, slots  146  may have a shapes with a single bend, shapes with one or more bends, shapes with two or more bends, shapes with locally widened portions, etc. Slots  146  of  FIGS. 9 and 10  are merely illustrative. Ground plane  104  of slot antenna structures  140  may be formed from metal traces on a printed circuit or plastic carrier, metal traces on other substrates, metal that forms part of an external housing wall or other portion of a metal housing (see, e.g., housing  12 , which may have a planar rear wall portion and vertically extending sidewall portions), metal that forms part of an electronic device, part of an internal housing structure, part of a metal bracket or other internal support structure, or other conductive structures in device  10 . Slots  146  may be filled with plastic (e.g., to prevent intrusion of dust and other substances into the interior of device  10  in a configuration in which slots  146  are formed in a metal housing such as housing  12  for device  10 ). Some or all of slots  146  may also be filled with other dielectric materials (e.g., air, glass, ceramic, etc.). 
     The performance of planar inverted-F antenna (PIFA) structures  140  of  FIG. 8  may be adjusted by adjusting the shape of resonating element  108  (e.g., by adjusting lateral dimensions D 1  and/or D 2  or other attributes of resonating element  108 ). The performance of slot antenna structures  144  may be adjusted by adjusting the size of slot  146  (e.g., by adjusting the perimeter of the slot). In narrow slots, for example, the resonance of a slot antenna structure will be influenced by adjustment of longitudinal dimension (length L) of slot  146 , because the perimeter of a narrow slot is about equal to twice its length. 
     Antenna(s)  40  of device  10  may be formed using hybrid planar inverted-F slot antenna(s). An illustrative hybrid PIFA slot antenna is shown in  FIG. 11 . Hybrid antenna  40  of  FIG. 11  is formed from both slot antenna structures  144  and planar inverted-F antenna structures  140 . 
     Illustrative hybrid planar inverted-F slot antenna  40  of  FIG. 11  has an antenna ground (ground  104  of  FIGS. 8, 9, and 10 ) that has been formed from metal housing  12 . Metal traces and/or other conductive structures may also be used in forming an antenna ground for hybrid antenna  40 . The configuration of  FIG. 11  in which metal electronic device housing  12  forms an antenna ground is merely illustrative. A ground plane may also be formed using metal traces on printed circuits, etc. 
     Slot  146  of  FIG. 11  may be formed in ground plane  12 . Slot  146  may be filled with plastic or other dielectric. In the example of  FIG. 11 , slot  146  has an open end such as end  150  and an opposing closed end such as closed end  148 . If desired, slot  146  may be a closed slot. Slot  146  has bend  210 . If desired, slot  146  may be provided with two bends, three or more bends, etc. The example of  FIG. 11  is merely illustrative. 
     In addition to slot antenna structures  144  formed from slot  146 , antenna  40  has planar inverted-F antenna structures  140 . Planar inverted-F antenna structures  140  may include resonating element structure  108  (e.g., a patch of metal). Patch  108  may have portions that protrude downwardly towards ground  12  such as leg  142  and leg  110 . Leg  142  may form part the feed for antenna  40 . Tip  216  of leg  142  is separated from ground plane  12  by a dielectric gap such as air gap D (i.e., tip  216  is not directly connected to ground  12 ). Return path  110  is coupled to patch  108  at connection point  152  and is connected to ground  12  at connection point  154 . 
     Transceiver circuitry  90  is coupled to antenna feed terminals such as terminals  98  and  100  by transmission line  92 . Terminal  98  may be connected to tip portion  216  of leg  142 . Terminal  100  may be connected to ground structure  12 . Positive signal line  94  may be coupled to terminal  98 . Ground signal line  96  may be coupled to terminal  100 . 
     Planar inverted-F antenna structures  140  are directly fed by the transmission line coupled to terminals  98  and  100 . Through near-field electromagnetic coupling and/or by providing antenna feed signals across slot  146  through structures  140 , planar inverted-F antenna structures  140  are coupled to slot antenna structures  146 . As a result, both slot antenna structures  145  and planar inverted-F antenna structures  140  contribute to the overall performance of hybrid antenna  40 . 
       FIG. 12  is a graph in which antenna performance (standing-wave ratio SWR) for the antenna structures of  FIG. 11  has been plotted as a function of antenna signal operating frequency f. Curve  164  corresponds to the response of planar inverted-F antenna structures  140 . Curve  164  may exhibit an antenna resonance at frequency f 2 . The position of the resonance at frequency f 2  may be adjusted by adjusting the lateral dimensions of patch  108  (as an example). Curve  162  corresponds to the response of slot antenna structures  144 . Curve  162  may exhibit an antenna resonance at frequency f 1 . The position of the resonance at frequency f 1  may be adjusted by adjusting the length of slot  146  in slot antenna structures  144 . The overall performance of antenna structures  40  is given by curve  160 . As shown in  FIG. 12 , curve  160  reflects contributions from both slot antenna structures  144  and from planar inverted-F antenna structures  140 . Curve  160  may, for example, have a first resonance at f 1  that is influenced by the characteristics of slot antenna structures  144  and may have a second resonance at f 2  that is influenced by the characteristics of planar inverted-F antenna structures  140 . 
     The use of the hybrid antenna arrangement for antenna  40  allows the advantages of the planar inverted-F antenna portion of antenna  40  to be exploited at frequency f 2  (i.e., the ability of planar inverted-F antenna structures  140  to exhibit good antenna efficiency and high bandwidth at frequency f 2 ), while allowing the advantages of the slot antenna portion of antenna  40  to be exploited at frequency f 1  (i.e., the ability of slot antenna structures  144  to exhibit good antenna efficiency and bandwidth at frequency f 1 ). 
     With one suitable arrangement, antenna  40  may be a dual band antenna for wireless local area network signals (e.g., IEEE 802.11 signals), frequency f 2  may be 5 GHz, and frequency f 1  may be 2.4 GHz. In this type of arrangement, PIFA structures  140  may be efficient at 5 GHz, but may not be as efficient at 2.4 GHz, particularly in configurations in which vertical height H of patch  108  above ground plane  12  is limited (e.g., in compact devices where available antenna height is constrained), whereas slot antenna structures  146  may be efficient at 2.4 GHz. The complementary nature of hybrid antenna  40  allows the positive attributes of each type of antenna to be used, thereby ensuring that both the low band (f 1 ) and high band (f 2 ) ranges are effectively covered by antenna  40 . 
     Another illustrative arrangement for hybrid antenna  40  is shown in  FIG. 13 . As shown in  FIG. 13 , housing  12  may have planar rear wall portion  12 R and sidewalls such as vertical sidewalls  12 W- 1  and  12 W- 2 . Sidewalls  12 W- 1  and  12 W- 2  may be flat or curved. Slot  146  may extend away from planar rear wall  12 R and up a sidewall such as sidewall  12 W- 1  in dimension Z. Slot  146  may have two bends such as bends  211  and  210  or may have other shapes. Antenna feed terminals  98  and  100  may be formed on the edge of slot  146  nearest sidewall  12 W- 1  and return path  110  may be formed on the opposing edge of slot  146 . 
     Antennas such as hybrid antenna  40  may be used in an array of two or more antennas. For example, a first antenna such as antenna  40  of  FIG. 13  may be formed along one portion of an edge of device  10  and a second antenna such as antenna  40  of  FIG. 13  may be formed along a second portion of the edge of device  10 . The antennas may be used in a multiple-input-multiple output (MIMO) array or other array (e.g., for wireless local area networking or other wireless communications). If desired, device  10  may contain one or more antennas such as antenna  40  (e.g., for wireless local area network communications) and one or more cellular telephone antennas, satellite navigation system antennas, etc. 
     As an example, device  10  of  FIG. 14  has first antenna  40 A and second antenna  40 B. Antenna  40 A may be a hybrid planar inverted-F slot antenna (see, e.g., antenna  40  of  FIG. 13 ). Antenna  40 A may have planar inverted-F antenna structures  140  formed from patch resonating element  108 , return path  110 , and feed terminals  98  and  100 . Antenna  40 A may also have slot antenna structures  144  formed from slot  146  in ground plane  12  (e.g., a metal housing for device  10 ). Antenna  40 A may be used for wireless local area network communications. For example, antenna  40 A may be a dual band antenna covering signals at a low band of 2.4 GHz and a high band at 5 GHz. 
     Antenna  40 B may be an indirectly fed cellular telephone antenna. Antenna  40 B may be a slot antenna having a slot such as slot  204  in a ground formed from metal housing  12  or other metal structures. Antenna  40 B may be fed using a near-field coupled feed structure such as structure  210 . Structure  210  may, as an example, have a patch such as metal patch  208 . A transmission line may have a positive signal line coupled to positive feed terminal  202  on leg  212  of feed structure  210  and may have a ground line coupled to ground feed terminal  200  on ground  12 . The transmission line may convey signals for antenna  40 B to feed structure  210 . Feed structure  210  may be electromagnetically coupled to slot  204  through near field electromagnetic coupling (i.e., structure  210  may indirectly feed a slot antenna formed from slot  204 ). Slot  204  may be an open slot (as an example). Antenna  40 B may be used in handling cellular telephone signals at frequencies of 700-2700 MHz or other suitable frequencies. 
     If desired, antenna structures for antenna  40  may be supported using a plastic support structure. The plastic support structure may also serve as a speaker cavity (sometimes referred to as a speaker box). A cross-sectional side view of an illustrative speaker box for device  10  is shown in  FIG. 15 . As shown in  FIG. 15 , speaker box  250  may have speaker box cavity  252  formed within speaker box wall structure  254 . Wall structure  254  may be a hollow plastic box and may have an acoustic port covered with mesh to prevent the intrusion of dust and moisture while allowing sound to escape from air-filled cavity  252  within the box. Speaker driver  256  may be located within cavity  252 . Optional metal structure  258  may be incorporated into box  250  (e.g., to allow the thickness of wall  254  to be thinned). Metal structure  258  may, for example, be located over driver  256 . 
     Antenna structures can be supported by speaker box  250 . As shown in  FIG. 16 , for example, patch antenna resonating element  108  of planar inverted-F antenna structures  140  in antenna  40  may be supported by box  250  (e.g., in a portion of box  250  such as region  260  that does not overlap driver  256 ). Box  250  may run parallel to at least some of the portions of slot  146  in slot antenna structures  144 . For example, box  250  may have an elongated shape that extends parallel to the edge of housing  12 . 
     The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20140424
Publication Date: 20170808
Grant Date: 20170808
Priority Date: 20140424
Inventors: ZHU JIANG
GOMEZ ANGULO RODNEY A.
LI QINGXIANG
SCHLUB ROBERT W.
HU HONGFEI
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/2266", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/28", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q13/10", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q9/0421", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/2266", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/0421", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/28", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q13/10", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 54335624