PATENT DOCUMENT

Publication Number: US-9583838-B2
Application Number: US-201414220467-A
Country: US
Kind Code: B2

Title: Electronic device with indirectly fed slot antennas

Abstract:
An electronic device may be provided with antennas. Antennas for the electronic device may be formed from slot antenna structures. A slot antenna structure may be formed from portions of a metal housing for an electronic device. The slots of the slot antenna structures may be indirectly fed to form first and second indirectly fed slot antennas. The first and second indirectly fed slot antennas may be formed from slots in a rear surface of an electronic device and a sidewall of the electronic device. The slots may have open ends along an edge of the sidewall and may have closed ends that face each other. A hybrid antenna may also be formed in the electronic device.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a metal housing that forms a ground plane, wherein a slot is formed in the ground plane, the slot has a bend, the metal housing has a planar rear wall and a sidewall that extends from the rear wall, the slot is formed in the rear wall and the sidewall, the slot extends from a first edge of the sidewall to an opposing second edge of the sidewall, and the slot has an opening along the second edge of the sidewall; 
 an indirectly fed slot antenna formed from the slot, the indirectly fed slot antenna comprising a near-field-coupled antenna feed structure that is formed from a planar metal structure that is near-field coupled to the slot; 
 a first tunable component coupled across the slot at a first side of the near-field-coupled antenna feed structure; and 
 a second tunable component coupled across the slot at a second side of the near-field coupled antenna feed structure. 
 
     
     
       2. The electronic device defined in  claim 1  wherein the planar metal structure comprises a patch of metal that overlaps the slot. 
     
     
       3. The electronic device defined in  claim 1  further comprising a display mounted in the metal housing. 
     
     
       4. An electronic device, comprising:
 a metal housing having at least first and second slots, wherein portions of the metal housing run along opposing sides of the first slot and portions of the metal housing run along opposing sides of the second slot, the first slot has a first segment, a second segment that extends substantially perpendicular to the first segment, and a third segment coupled between the first and second segments, the first and second segments have a first width, and the third segment has a second width that is greater than the first width; 
 a first indirectly fed slot antenna formed from the first slot, wherein the first indirectly fed slot antenna comprises a first near-field coupled antenna feed structure having a first metal structure that overlaps the first slot and that is separated from the first slot; and 
 a second indirectly fed slot antenna formed from the second slot, wherein the second indirectly fed slot antenna comprises a second near-field coupled antenna feed structure having a second metal structure that overlaps the second slot and that is separated from the second slot. 
 
     
     
       5. The electronic device defined in  claim 4  wherein the metal housing has a metal rear wall and has metal sidewalls, the first segment of the first slot is formed in the metal rear wall and in a given one of the metal sidewalls, and the second slot has a portion in the metal rear wall and a portion in the given one of the metal sidewalls. 
     
     
       6. The electronic device defined in  claim 5  further comprising a third antenna having a third slot in the metal housing. 
     
     
       7. The electronic device defined in  claim 6  wherein the third slot is formed at least partly in the given one of the metal sidewalls. 
     
     
       8. The electronic device defined in  claim 7  wherein the third antenna comprises a hybrid antenna having a slot antenna portion formed from the third slot and having a planar inverted-F antenna portion. 
     
     
       9. The electronic device defined in  claim 8  wherein a portion of the third slot is formed in the metal rear wall and portions of the metal rear wall run along opposing sides of the third slot. 
     
     
       10. The electronic device defined in  claim 9  wherein the given one of the metal sidewalls has an edge and the first and second slots are open slots having respective first and second slot openings that are located along the edge of the given one of the metal sidewalls. 
     
     
       11. The electronic device defined in  claim 4  further comprising a third antenna having a third slot in the metal housing. 
     
     
       12. The electronic device defined in  claim 11  wherein the third antenna comprises a hybrid antenna having a slot antenna portion formed from the third slot and having a planar inverted-F antenna portion. 
     
     
       13. An electronic device, comprising:
 a metal housing having a rear wall, a sidewall that extends from the rear wall, and first and second slots, wherein the first slot has an open end formed at a first edge of the sidewall and an opposing closed end formed in the rear wall, the second slot has an open end formed at the first edge of the sidewall and an opposing closed end formed in the rear wall, the first and second slots each extend from a second edge of the sidewall to the first edge of the sidewall, portions of the rear wall are on opposing sides of the first slot and at the closed end of the first slot, portions of the rear wall are on opposing sides of the second slot and at the closed end of the second slot, and the metal housing forms a ground plane; 
 a first indirectly fed slot antenna formed from the first slot, wherein the first indirectly fed slot antenna is fed using a first antenna feed element; and 
 a second indirectly fed slot antenna formed from the second slot, wherein the second indirectly fed slot antenna is fed using a second antenna feed element that is different from the first antenna feed element. 
 
     
     
       14. The electronic device defined in  claim 13  wherein the closed ends of the first and second slots face each other and are separated by portions of the rear wall. 
     
     
       15. The electronic device defined in  claim 13 , wherein the first slot comprises a first segment and a second segment, the second segment extends substantially perpendicular to the first segment and towards the second slot, the second slot comprises a third segment and a fourth segment, and the fourth segment extends substantially perpendicular to the third segment and towards the first slot. 
     
     
       16. The electronic device defined in  claim 15 , wherein a portion of the rear wall separates the fourth segment from the second segment, and the first and third segments have the same length. 
     
     
       17. The electronic device defined in  claim 16 , further comprising:
 a first tunable component coupled across the first slot at a first side of the first antenna feed element; and 
 a second tunable component coupled across the first slot at a second side of the first antenna feed element. 
 
     
     
       18. The electronic device defined in  claim 1 , wherein the first tunable component comprises a tunable inductor and the second tunable component comprises a tunable capacitor.

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 antennas. The antennas may include a primary antenna and a secondary antenna that are coupled to radio-frequency transceiver circuitry by switching circuitry. The switching circuitry may be adjusted to switch a desired one of the antennas into use. Additional antennas such as a hybrid antenna may also be incorporated into the electronic device. 
     The antennas for the electronic device may be formed from slot antenna structures. A slot antenna structure may be formed from portions of a metal housing for an electronic device. For example, slots may be formed within the rear metal wall of a housing and a metal sidewall in the housing. 
     The slots of the slot antenna structures may be indirectly fed to form first and second indirectly fed slot antennas. The first and second indirectly fed slot antennas may be formed from slots in a rear surface of an electronic device and a sidewall of the electronic device. The slots may have open ends along an edge of the sidewall. 
     A hybrid antenna may also be formed in the electronic device. The hybrid antenna may have a slot antenna portion and may have a planar inverted-F antenna portion each of which contributes to the overall frequency response of the hybrid antenna. The slot antenna portion of the hybrid antenna may be formed from a slot in a metal housing or other conductive structures. For example, the slot antenna portion of the hybrid antenna may be formed from a slot that extends through a rear metal housing wall and a metal sidewall having an edge. The slot may have an opening along the edge of the metal sidewall. 
    
    
     
       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 schematic diagram of illustrative wireless circuitry in which multiple antennas have been coupled to transceiver circuitry using switching circuitry in accordance with an embodiment. 
         FIG. 8  is a diagram of an illustrative inverted-F antenna in accordance with an embodiment. 
         FIG. 9  is a diagram of an illustrative antenna that is fed using near-field coupling in accordance with an embodiment. 
         FIG. 10  is a perspective view of a slot antenna being fed using near-field coupling in accordance with an embodiment. 
         FIG. 11  is a perspective view of an interior portion of an electronic device housing having a pair of slots and associated near-field coupling structures in accordance with an embodiment. 
         FIG. 12  is a perspective view of an illustrative interior portion of an electronic device having electronic device housing slots with multiple widths that are fed using near-field coupling structures and having a hybrid antenna that includes a planar inverted-F antenna structure and a slot antenna structure in accordance with an embodiment. 
         FIG. 13  is a diagram showing how electrical components may be incorporated into a slot antenna to adjust antenna performance in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices may be provided with antennas. The antennas may include slot antennas formed in device structures such as electronic device housing structures. Illustrative electronic devices that have housings that accommodate slot antennas 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 table top 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  104  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  100 . 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. 
     As shown in  FIG. 7 , antenna structures  40  may include multiple antennas such as secondary antenna  40 A and primary antenna  40 B. Primary antenna  40 B may be used for transmitting and receiving wireless signals. Secondary antenna  40 A may be switched into use when antenna  40 B is blocked or otherwise degraded in performance (e.g., to receive and, if desired, to transmit wireless signals). Switching circuitry  200  may be used to select which of antennas  40 A and  40 B is coupled to transceiver circuitry  90 . If desired, primary antenna  40 B and/or secondary antenna  40 A may cover multiple frequency bands of interest (e.g., a low band cellular band, a midband cellular band including GPS coverage, and a high band cellular band that may cover 2.4 GHz communications, if desired). Other communications band may be covered using antennas  40 A and  40 B, if desired. 
       FIG. 8  is a diagram of illustrative inverted-F antenna structures that may be used in forming an antenna in device  10 . Inverted-F antenna  40  of  FIG. 8  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  40  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  40  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 antennas such as illustrative antenna  40  of  FIG. 4  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. 8 ). 
       FIG. 9  shows how antenna  40  may be indirectly fed using a near-field coupling arrangement. With this type of arrangement, transceiver  90  is connected to near-field-coupled antenna feed structure  202  by transmission line  92 . Antenna  40  may include a resonating element such as a slot or other antenna resonating element structure (antenna element  40 ′). Structure  202  may include a strip of metal, a patch of metal, planar metal members with other shapes, a loop of metal, or other structure that is near-field coupled to antenna resonating element  40 ′ by near-field coupled electromagnetic signals  204 . Structure  202  does not produce significant far-field radiation during operation (i.e., structure  202  does not itself form a far-field antenna but rather serves as a coupled feed for a slot antenna structure or other antenna resonating element structure for antenna  40 ). During operation, the indirect feeding of element  40 ′ by structure  202  allows antenna element  40 ′ and therefore antenna  40  to receive and/or transmit far-field wireless signals  205  (i.e., radio-frequency antenna signals for antenna  40 ). 
     A perspective view of an illustrative indirectly feed (coupled feed) configuration in which a slot-based antenna is being indirectly fed is shown in  FIG. 10 . With the arrangement of  FIG. 10 , antenna  40  is a slot-based antenna formed from slot  206  in a ground plane structure such as metal housing  12  of device  10 . Slot  206  may be filled with plastic or other dielectric. In the example of  FIG. 10 , slot  206  has an open end such as end  218  and an opposing closed end such as closed end  208 . A slot antenna such as slot antenna  40  of  FIG. 10  that has an open end and a closed end may sometimes be referred to as an open slot antenna. If desired, slot antenna  40  may be a closed slot antenna (i.e., end  218  may be closed by providing a short circuit path across the slot opening at end  218  so that both ends of the slot are closed). Slot antenna  40  of  FIG. 10  is based on a slot that has bend  210 . If desired, slots for slot antennas such as slot  206  may be provided with two bends, three or more bends, etc. The example of  FIG. 10  is merely illustrative. 
     Slot antenna  40  may be near-field coupled to near-field-coupled antenna feed structure  202 . Structure  202  may be formed from a patch of metal such as patch  212  with a bent leg such as leg  214 . Leg  214  extends downwards towards ground plane  12 . Tip  216  of leg  214  is separated from ground plane  12  by air gap D (i.e., tip  216  is not directly connected to ground  12 ). 
     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  214  of near-field-coupled antenna feed structure  202 . 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 . 
     Near-field-coupled antenna feed structure  202  is near-field coupled to slot antenna  40  by near-field electromagnetic signals and forms an indirect antenna feed for antenna  40 . During operation, transceiver circuitry  90  can transmit and receive wireless radio-frequency antenna signals with antenna  40  (i.e., with slot  206 ) using coupled feed structure  202 . 
       FIG. 11  is a perspective interior view of an illustrative configuration that may be used for housing  12 . Housing  12  of  FIG. 11  has a rear wall such as planar rear wall  12 - 1  and has flat or curved sidewalls  12 - 2  that run around the periphery of rear wall  12 - 1  and that extend vertically upwards to support display  14  (not shown in  FIG. 11 ). 
     Slots  206 A and  206 B are formed in housing walls  12 - 1  and  12 - 2 . Plastic or other dielectric may be used to fill slots  206 A and  206 B. Slots  206 A and  206 B may be open ended slots having closed ends  208  and open ends  218  or one or both of slots  206 A and  206 B may be closed slots. Slots  206 A and  206 B may have bends such as bends  210 - 1  and  210 - 2  that allow slots  206 A and  206 B to extend across portions of rear wall  12 - 1  and up side walls  12 - 2 . Openings  218  may be formed along upper edge  220  of housing sidewall  12 . Near-field-coupled antenna feed structure  202 A is electromagnetically coupled to slot  206 A and allows slot antenna  40 A to be indirectly feed by transceiver circuitry  90  using terminals  98 A and  100 A. Near-field-coupled antenna feed structure  202 B is electromagnetically coupled to slot  206 B and allows slot antenna  40 B to be indirectly feed by transceiver circuitry  90  using terminals  98 B and  100 B. Switching circuitry such as switching circuitry  200  of  FIG. 7  may be used to couple transceiver circuitry  90  to antennas  40 A and  40 B. Antenna  40 A may be a secondary antenna and antenna  40 B may be a primary antenna (or vice versa). Additional indirectly fed slot antennas  40  may be incorporated into housing  12 , if desired. The two-antenna configuration of  FIG. 11  is merely illustrative. 
       FIG. 12  is a perspective interior view of another illustrative configuration that may be used for providing slot antennas in housing  12 . Housing  12  of  FIG. 12  has a rear wall such as planar rear wall  12 - 1  and has flat or curved sidewalls  12 - 2  that extend upwards from the rear wall around the periphery of device  10 . Slots  206 A,  206 B, and  206 C may be formed in housing walls  12 - 1  and  12 - 2 . Plastic or other dielectric may be used to fill slots  206 A,  206 B, and  206 C. Slots  206 A,  206 B, and  206 C may be open ended slots having closed ends  208  and open ends  218  or one or more of slots  206 A.  206 B, and  206 C may be closed slots that are surrounded on all sides by metal (e.g., metal housing  12 ). 
     Slots  206 A,  206 B, and  206 C may have bends that allow slots  206 A,  206 B, and  206 C to extend across portions of rear wall  12 - 1  and up a given one of sidewalls  12 - 2 . Openings  218  may be formed along upper edge  220  of housing wall  12 . Slots  206 A and  206 B may have locally widened portions such as portions  222  (i.e., portions along the lengths of slots  206 A and  206 B where the widths of the slots have been widened relative to the widths of the slots elsewhere along their lengths). The locally widened slot portion of each slot may exhibit a reduced capacitance that improves low band antenna efficiency. 
     Antennas  40 A and  40 B may be indirectly fed slot antennas. Near-field-coupled antenna feed structure  202 A may be electromagnetically coupled to slot  206 A and may allow slot antenna  40 A to be indirectly feed by transceiver circuitry  90  using terminals  98 A and  100 A. Near-field-coupled antenna feed structure  202 B may be electromagnetically coupled to slot  206 B and may allow slot antenna  40 B to be indirectly feed by transceiver circuitry  90  using terminals  98 B and  100 B. Switching circuitry such as switching circuitry  200  of  FIG. 7  may be used to couple transceiver circuitry  90  to antennas  40 A and  40 B. Antenna  40 A may be a secondary antenna and antenna  40 B may be a primary antenna (or vice versa). 
     Antenna  40 C may be a hybrid antenna that incorporates a slot antenna and a planar inverted-F antenna. The slot antenna portion of antenna  40 C may be formed from slot  206 C. The planar inverted-F portion of antenna  40 C may be formed from a planar inverted-F antenna having main planar resonating element portion  108  (e.g., a rectangular metal patch or a planar metal structure with another suitable shape), a downward-extending leg forming feed path  112 , and another downward-extending leg forming return path  110 . Antenna  40 C may be fed using positive antenna feed terminal  98 C (i.e., a feed terminal on the tip of leg  112  that is separated from ground  12 - 1  by an air gap or other dielectric gap) and ground antenna feed terminal  100 C (e.g., a terminal directly shorted to ground  12  on an opposing side of slot  206 C from terminal  98 C or shorted to ground  12  elsewhere on rear wall  12 - 1 ). 
     Antenna  40 C may operate in one or more communications bands of interest. Both the slot antenna portion of antenna  40 C formed from slot  206 C and the planar inverted-F antenna portion of antenna  40 C may contribute to the antenna performance of antenna  40 C (i.e., both the slot antenna and planar inverted-F antenna may contribute to the antenna resonances of antenna  40 C). This allows the hybrid antenna to effectively cover communications frequencies of interest. With one suitable arrangement, antenna  40 C may operate in 2.4 GHz and 5 GHz communications bands (e.g., to support wireless local area network communications). 
     If desired, slot antennas in housing  12  may be provided with electrical components such as inductors, capacitors, resistors, and more complex circuitry formed from multiple circuit elements such as these. The components may be packed in surface mount technology (SMT) packages or other packages. 
     The presence of additional electrical components in an antenna may be used to adjust antenna performance, so the antenna covers desired operating frequencies of interest. Consider, as an example, indirectly fed slot antenna  40  of  FIG. 13 . As shown in  FIG. 13 , antenna  40  may have a near-field-coupled antenna feed structure  202  that is used to provide an indirect feed arrangement for slot antenna  40 . Transceiver circuitry  90  may be coupled to feed terminals  98  and  100 , as described in connection with  FIG. 10 . Capacitor C and/or inductor L may be incorporated into antenna  40  using surface mount technology components or other electrical components. One or more capacitors such as capacitor C may, for example, bridge slot  206  at one or more locations along the length of slot  206 . Capacitor C may be implemented using a discrete capacitor or other capacitor structures. Inductor L may be used to form closed end  208  of slot  206  and may be formed from a discrete inductor and/or a length of metal with an associated inductance. The inclusion of capacitor C into antenna  40  may help reduce the size of antenna  40  (e.g., the length of slot  206 ) while ensuring that antenna  40  can continue to operate in desired communications bands. The inclusion of inductor L into antenna  40  may somewhat reduce low band antenna efficiency, but will also help reduce the size of antenna  40  (e.g., by minimizing slot length). Elements such as inductor L and capacitor C may, if desired, be tunable elements so that antenna  40  can be tuned to cover frequencies of interest, as described in connection with tunable components  102  of  FIG. 6 . The use of coupled (indirect) feeding arrangements for the slot antennas in device  10  may help increase antenna bandwidth while minimizing slot length requirements (e.g., by shifting maximum antenna currents towards the edge of housing  12  or via other mechanisms). Other types of feeding arrangements may be used, if desired. 
     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: 20140320
Publication Date: 20170228
Grant Date: 20170228
Priority Date: 20140320
Inventors: ZHU JIANG
RAJAGOPALAN HARISH
GOMEZ ANGULO RODNEY A.
LI QINGXIANG
SCHLUB ROBERT W.
RAFF JOHN
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q13/103", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q13/10", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q5/40", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/2258", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/2266", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q13/10", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q13/103", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/2266", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/2258", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q5/40", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q5/40", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/2266", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q13/103", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 54142964