PATENT DOCUMENT

Publication Number: US-9455489-B2
Application Number: US-201113221554-A
Country: US
Kind Code: B2

Title: Cavity antennas

Abstract:
Cavity antennas may be provided for electronic devices. A cavity antenna may have a conductive antenna cavity with an opening. An antenna resonating element may be soldered within the cavity opening. An electronic device may have a display that is covered by a display cover layer. A cavity antenna may be mounted so that the cavity opening is located under a portion of the display cover layer outside of the active display region. An antenna cavity for a cavity antenna may have one or more bends. A curved antenna cavity or a cavity antenna with one or more angled branches may have a portion that extends between a conductive housing wall and internal device components such as a display. A speaker may be formed using the interior volume within a cavity antenna.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a conductive housing having a rear wall; 
 a cavity antenna having an antenna cavity with conductive walls and an antenna resonating element, wherein the antenna cavity has an opening in which the antenna resonating element is located, the antenna cavity has curved portions that are located between the at least one conductive internal component and the conductive housing, the antenna cavity has a T-shape, and the antenna cavity comprises a first portion extending from the opening and first and second branching portions extending from opposing sides of the first portion; 
 a display cover layer; 
 a first electrical component within the conductive housing; and 
 a second electrical component within the conductive housing, wherein the first electrical component is interposed between the display cover layer and the first branching portion, the second electrical component is interposed between the display cover layer and the second branching portion, the first portion is interposed between the display cover layer and the rear wall, the first portion is interposed between the first and second electrical components, the first branching portion is interposed between the first electrical component and the rear wall, and the second branching portion is interposed between the second electrical component and the rear wall. 
 
     
     
       2. The electronic device defined in  claim 1  wherein the conductive housing comprises a metal housing wall. 
     
     
       3. The electronic device defined in  claim 2  wherein the first electrical component comprises a display. 
     
     
       4. The electronic device defined in  claim 3  wherein a region of the display cover layer covers the display and the opening is located adjacent to an area of the display cover layer outside of the region. 
     
     
       5. The electronic device defined in  claim 4  wherein the antenna resonating element comprises a laser-patterned antenna resonating element that is soldered to an edge of the conductive walls of the antenna cavity, wherein the edge surrounds the opening. 
     
     
       6. The electronic device defined in  claim 4  wherein the antenna resonating element comprises a two-shot plastic substrate. 
     
     
       7. The electronic device defined in  claim 1  wherein the cavity antenna is configured to operate at an operating frequency, wherein the antenna cavity has a curved shape characterized by a bend radius, and wherein the bend radius is greater than one quarter of a wavelength at the operating frequency. 
     
     
       8. The electronic device defined in  claim 7  further comprising a speaker having an interior chamber, wherein the conductive walls surround the interior chamber. 
     
     
       9. The electronic device defined in claim  8  wherein the speaker comprises a mesh covering the opening and the antenna resonating element. 
     
     
       10. Apparatus, comprising:
 conductive cavity walls forming an antenna cavity in a cavity antenna and forming an interior volume for a speaker, wherein the antenna cavity has an opening that serves as a speaker port through which sound produced by the speaker exits the speaker, the conductive cavity walls defining a cross-sectional area of the antenna cavity; 
 a diaphragm; and 
 a speaker driver attached to the diaphragm, wherein the diaphragm and the speaker driver are mounted within the antenna cavity and the diaphragm extends across an entirety of the cross-sectional area of the antenna cavity. 
 
     
     
       11. The apparatus defined in  claim 10  wherein the antenna cavity has a length with at least two bends. 
     
     
       12. The apparatus defined in  claim 10  wherein the antenna cavity comprises stamped metal walls and wherein the cavity antenna further comprises a laser-patterned antenna resonating element in the opening. 
     
     
       13. The apparatus defined in  claim 12  wherein the opening has an edge and wherein the apparatus further comprises solder connected to the antenna resonating element along at least part of the edge. 
     
     
       14. An electronic device, comprising:
 a conductive housing having a sidewall structure and a rear wall structure; 
 a display within the conductive housing, wherein the display comprises a display module and a display cover layer and the display module has a side surface and a rear surface; and 
 a cavity antenna having an antenna cavity with conductive walls and an antenna resonating element, wherein the antenna cavity has a first portion interposed between the side surface of the display module and the sidewall structure of the conductive housing, a second portion interposed between the rear surface of the display module and the rear wall structure of the conductive housing, and a curved portion that extends between the first and second portions. 
 
     
     
       15. The electronic device defined in  claim 14  wherein the cavity antenna is configured to operate at an operating frequency, wherein the curved portion is characterized by a bend radius, and wherein the bend radius is greater than one quarter of a wavelength at the operating frequency. 
     
     
       16. The electronic device defined in  claim 1 , wherein the first portion has first and second opposing ends, the first end is located adjacent to the opening, and the branching portions extend from the second end. 
     
     
       17. The electronic device defined in  claim 16 , wherein the first and second branching portions extend substantially perpendicular from the first portion. 
     
     
       18. The apparatus defined in  claim 10 , further comprising:
 an audio line connected to the speaker driver that provides audio signals to the speaker driver, wherein the diaphragm is interposed between the speaker driver and the opening of the antenna cavity and the diaphragm is driven by the speaker driver; 
 an acoustically transparent cover member formed over the opening of the antenna cavity; and 
 an antenna resonating element that is affixed to at least one of the cavity walls and that is interposed between the diaphragm and the acoustically transparent cover member.

Description:
BACKGROUND 
     This relates generally to antennas and, more particularly, to cavity antennas for electronic devices. 
     Electronic devices often have wireless communications circuitry. For example, electronic devices may contain antennas and radio-frequency transceiver circuitry that is used in transmitting and receiving cellular telephone signals, wireless local area network signals, and other wireless traffic. 
     It may sometimes be desirable to mount an antenna resonating element within a conductive cavity to form a cavity-backed antenna (“cavity antenna”). This type of type of approach may be used, for example, when it is desired to isolate an antenna resonating element from its immediate surroundings within an electronic device. In a typical configuration, a cavity may have a rectangular box shape with a rectangular opening in which an antenna resonating element is formed. 
     The use of conventional cavity antenna designs can help provide antennas with good immunity from surrounding structures in an electronic device and can help reduce the impact of manufacturing variations on antenna performance. Conventional cavity antennas may, however, be challenging to manufacture and may be challenging to mount within devices where space is constrained such as devices with compact housings. 
     It would therefore be desirable to be able to provide improved cavity antennas. 
     SUMMARY 
     Cavity antennas may be provided for electronic devices. A cavity antenna may have a conductive antenna cavity with an opening. An antenna resonating element may be mounted within the opening. The antenna resonating element may implemented using a laser-patterned antenna resonating element, an antenna resonating element formed from a two-shot plastic substrate, an antenna resonating element formed from a printed circuit substrate, or other types of antenna resonating element structure. The antenna resonating element may be soldered within the cavity opening so that the conductive material of the resonating element is electrically shorted to the conductive material of the cavity along at least part of the edge of the cavity opening. 
     An electronic device may have a display that is covered by a cover glass layer. The display and other internal device components may be mounted in an electronic device housing. 
     A cavity antenna may be mounted so that its cavity opening and resonating element lie under a portion of the cover glass layer outside of the portion covering the display. The cavity antenna may have cavity wall portions that bend or otherwise extend between internal electronic device components and portions of the electronic device housing. Extended antenna cavities such as these have curves, branches that surround internal device components, T shapes, and other shapes that help maximize the volume of the cavity while accommodating internal components in a device and other cavity mounting constraints. 
     A speaker may be formed using the interior volume within a cavity antenna. Speaker components such as a speaker diaphragm and a speaker driver may be mounted within the interior volume of the cavity antenna. 
     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 of the type that may be provided with one or more cavity antennas in accordance with an embodiment of the present invention. 
         FIG. 2  is a schematic diagram of an illustrative electronic device showing how radio-frequency transceiver circuitry in the electronic device may be coupled to one or more antennas such as one or more cavity antennas in accordance with an embodiment of the present invention. 
         FIG. 3  is an exploded perspective view of an illustrative cavity antenna having a bent cavity shape in accordance with an embodiment of the present invention. 
         FIG. 4  is a perspective view of an illustrative cavity antenna with an inverted-F antenna resonating element in accordance with an embodiment of the present invention. 
         FIG. 5  is a cross-sectional side view of an illustrative cavity antenna with a bend that has been mounted within an electronic device in accordance with an embodiment of the present invention. 
         FIG. 6  is a cross-sectional side view of an illustrative cavity antenna with a curved shape that has been mounted within an electronic device in accordance with an embodiment of the present invention. 
         FIG. 7  is a perspective view of an illustrative T-shaped cavity for a cavity antenna in accordance with an embodiment of the present invention. 
         FIG. 8  is a cross-sectional side view of a cavity antenna having a T-shaped cavity of the type shown in  FIG. 7  in a configuration in which the cavity antenna has been mounted within an electronic device in accordance with an embodiment of the present invention. 
         FIG. 9  is a perspective view of an illustrative cavity for a cavity antenna showing how the cavity may have a curved shape with a pair of cavity branches that extend past both sides of a device component in accordance with an embodiment of the present invention. 
         FIG. 10  is a perspective view of an illustrative tube-shaped cavity for a cavity antenna in accordance with an embodiment of the present invention. 
         FIG. 11  is a side view of an illustrative cavity antenna with an asymmetric T shape in accordance with an embodiment of the present invention. 
         FIG. 12  is a side view of an illustrative cavity antenna with a symmetric T shape in accordance with an embodiment of the present invention. 
         FIG. 13  is a side view of an illustrative cavity antenna with a bend in accordance with an embodiment of the present invention. 
         FIG. 14  is a side view of an illustrative cavity antenna with multiple bent branches in accordance with an embodiment of the present invention. 
         FIG. 15  a side view of an illustrative cavity antenna having a portion characterized by a bend radius in accordance with an embodiment of the present invention. 
         FIG. 16  is a side view of an illustrative cavity antenna with a pair of flared branches that form a T shape in accordance with an embodiment of the present invention. 
         FIG. 17  is a side view of an illustrative cavity antenna having multiple chambers connected in series in accordance with an embodiment of the present invention. 
         FIG. 18  is a perspective view of an illustrative speaker box that also serves as a cavity antenna in accordance with an embodiment of the present invention. 
         FIG. 19  is a cross-sectional side view of the illustrative speaker box cavity antenna of  FIG. 18  in accordance with an embodiment of the present invention. 
         FIG. 20  is a perspective view of a cavity such as a speaker-box cavity having multiple consecutive bends in accordance with an embodiment of the present invention. 
         FIG. 21  is top view of an illustrative electronic device showing where a cavity antenna of the type shown in  FIG. 20  may be mounted in accordance with an embodiment of the present invention. 
         FIG. 22  is diagram showing how a laser-patterned antenna resonating element may be attached to a conductive cavity to form a cavity antenna in accordance with an embodiment of the present invention. 
         FIG. 23  is a perspective view of a slot antenna resonating element of the type that may be used in a cavity antenna in accordance with an embodiment of the present invention. 
         FIG. 24  is diagram showing how an antenna resonating element for a cavity antenna may be formed using a two-shot molding process and electroplating in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices such as electronic device  10  of  FIG. 1  may be provided with wireless communications circuitry. The wireless communications circuitry may be used to support wireless communications in cellular telephone bands, wireless local area network bands, and other wireless communications bands. The wireless communications circuitry may include one or more antennas. For example, one or more antennas may be used to handle cellular telephone bands, one or more antennas may be used to handle wireless local area network bands, and additional antennas may be used in handling additional communications bands of interest. 
     The antennas within device  10  may be based on inverted-F antenna resonating elements, planar inverted-F antenna resonating elements, open or closed slot antenna resonating elements, monopoles, dipoles, L-shaped antenna resonating elements, patch antenna resonating elements, loop antenna resonating elements, or any other suitable type of antenna resonating element. The antenna resonating elements may be mounted in conductive cavities to form cavity antennas (also sometimes referred to as cavity-backed antennas). 
     Device  10  of  FIG. 1  may include one or more different types of cavity antenna. With one suitable arrangement, which is sometimes described herein as an example, device  10  may be provided with one or more antenna cavities that are bent along their length. The bent or otherwise non-uniform shape of this type of cavity antenna may be exploited to help mount the cavity antenna within the potentially compact confines of electronic device  10 . If desired, a cavity antenna for device  10  may be formed using a cavity structure that serves both as an antenna cavity and as an internal speaker volume (sometimes referred to as a speaker box or speaker cavity). This type of arrangement may help conserve space within device  10 . Cavity antennas may be formed from antenna resonating elements that are soldered onto a metal cavity structure or may be formed using other suitable arrangements. 
     Electronic device  10  of  FIG. 1  may be a portable electronic device or other suitable electronic device. For example, electronic device  10  may be a laptop computer, a tablet computer, a somewhat smaller device such as a wrist-watch device, pendant device, headphone device, earpiece device, or other wearable or miniature device, a cellular telephone, a media player, etc. 
     Device  10  may include a housing such as housing  12 . Housing  12 , which may sometimes be referred to as a case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of these materials. In some situations, parts of housing  12  may be formed from dielectric or other low-conductivity material. In other situations, housing  12  or at least some of the structures that make up housing  12  may be formed from metal elements. In a housing configuration with conductive structures, a cavity antenna may be configured to place a cavity opening and an associated antenna resonating element adjacent to dielectric structures (e.g., portions of a display, a dielectric antenna window, portions of dielectric housing, etc.). This type of arrangement may allow antenna signals to be transmitted and received through the dielectric structures. Other portions of the cavity antenna may be recessed within the interior of the electronic device housing. 
     Device  10  may, if desired, have a display such as display  14 . Display  14  may, for example, be a touch screen that incorporates capacitive touch electrodes. Display  14  may include image pixels formed from light-emitting diodes (LEDs), organic LEDs (OLEDs), plasma cells, electronic ink elements, liquid crystal display (LCD) components, or other suitable image pixel structures. A cover glass layer may cover the surface of display  14 . Portions of display  14  within rectangular region  20  may correspond to the active part of display  14 . In active display region  20 , an array of image pixels may be used to display images for a user. Portions of display  14  such as peripheral regions  28  surrounding rectangular active region  20  may be inactive and may be devoid of image pixel structures. 
     The cover glass layer that covers display  14  may have openings such as a circular opening for button  16  and a speaker port opening such as speaker port opening  18  (e.g., for an ear speaker for a user). Openings  16  and  18  may, for example, be formed in inactive portion  28  of display  14 . Device  10  may also have other openings (e.g., openings in display  14  and/or housing  12  for accommodating volume buttons, ringer buttons, sleep buttons, and other buttons, openings for an audio jack, data port connectors, removable media slots, etc.). For example, the portion of housing  12  at the lower end of device  10  or other suitable portion of device  10  may have openings to form speaker port  22 , connector port  24 , and microphone port  26  (as an example). 
       FIG. 2  is a diagram of illustrative components and circuitry that may be used in forming electronic device  10 . As shown in  FIG. 2 , device  10  may have control circuitry  32 . Control circuitry  32  may include processing circuitry such as one or more microprocessors, one or more microcontrollers, digital signal processors, application-specific integrated circuits, and other processing circuits. Control circuitry  32  may also have non-volatile and volatile storage (e.g., memory such as random-access memory, hard disk drives, solid state drives, etc.). The storage and processing circuitry of control circuitry  32  may be used to generate data that is to be wirelessly transmitted using radio-frequency transceiver circuitry  34  and, during signal reception operations, may be used to process incoming data that has been received by transceiver circuitry  34 . 
     Transceiver circuitry  34  may include one or more radio-frequency transmitters and one or more radio-frequency receivers. During signal transmission operations, data that has been received from control circuitry  32  may be transmitted over one or more of antennas  36  using a transmitter in transceiver circuitry  34 . During signal reception operations, data that has been transmitted to device  10  from an external source may be received by one or more of antennas  36  and radio-frequency receiver circuitry in transceiver  34 . 
     Antennas  36  may include cavity antennas, non-cavity antennas, combinations of one or more cavity antennas and one or more non-cavity antennas, or other suitable antenna structures. 
     Control circuitry  32  may be coupled to electrical components such as input-output devices  30 . Input-output devices  30  may include displays for displaying information to a user, sensors, keyboards, keypads, touch sensors (e.g., touch sensor arrays that are incorporated into displays), speakers, microphones, vibrators, light-emitting diodes (status indicator lights), input-output ports, and other circuitry and components for facilitating the process of providing a user with output and with gathering input from the user. 
     An illustrative cavity antenna is shown in  FIG. 3 . As shown in the exploded perspective view of  FIG. 3 , cavity antenna  36  may have a conductive cavity such as conductive cavity  36 A and an antenna resonating element such as antenna resonating element  36 B. Antenna resonating element  36 B may be formed from conductive structures such as patterned conductive traces  38  on a dielectric substrate and may have any suitable configuration (e.g., an inverted-F configuration, a loop antenna configuration, a slot antenna configuration, etc.). 
     Cavity  36 A may have conductive walls  40 . Walls  40  may have edges  44  that surround an opening such as cavity opening  42 . When assembled, antenna resonating element  36 B may be mounted within opening  42  (e.g., on edges  44 ). 
     As shown in the example of  FIG. 36A , cavity  36 A may be shaped to facilitate mounting within electronic device housing  12 . In particular, cavity walls  40  may be configured so that there is a bent (curved) portion such as bend  46  or other suitable curved portion along the length L of cavity  36 A. Bend  46  separates straight portions  48  and  50  of cavity  36 A from each other. Curved portion  46  in the  FIG. 3  example forms a 90° bend, but other shapes for cavity  36 B may be used if desired. 
     For optimal performance, it may be desirable to ensure that the volume of cavity  36 B is not too small. Excessively small cavity volumes may decrease the bandwidth of antenna  36 . With one suitable arrangement, length (depth) L of cavity  36 B is not too small and perimeter P of cavity  36 B is not too small. The dimensions of cavity  36 B (e.g., length L, the lateral cavity dimensions perpendicular to L, perimeter P, etc.) are preferably at least one eighth of a wavelength at an operating frequency of interest and are preferably at least one quarter of a wavelength or one half of a wavelength or more. In some configurations, it may be desirable to form cavity walls  40  so that L is equal to about one quarter or one half of a wavelength at the operating frequency of antenna  36  (e.g., to help produce constructive interference). These are merely illustrative configurations that may be used for cavity  40 . Any suitable cavity sizes and shapes may be used if desired. 
     As shown in  FIG. 4 , antenna resonating element  36 B in cavity antenna  36  may have an antenna feed formed from positive antenna feed terminal  52  and ground antenna feed terminal  54 . Patterned antenna resonating element conductive structures such as illustrative trace  38  of  FIG. 4  may be electrically connected to cavity  36 A, which may serve as ground for antenna  36 . The electrical connection between trace  38  and the cavity may be formed using solder or other electrically conductive materials and may be located along at least some of the edge of the cavity opening. With this type of configuration, ground antenna terminal  54  for the antenna feed for antenna resonating element  36 B may be connected to a portion of antenna cavity  36 A. 
     A transmission line may be coupled between the antenna feed for antenna resonating element  36 B and transceiver circuitry  34  ( FIG. 2 ). The transmission line may include structures such as microstrip transmission line structures, coaxial cable transmission line structures, etc. If desired, circuitry such as filters, impedance matching circuits, and other components may be interposed within the path between transceiver circuitry  34  and the feed for antenna resonating element  36 . In the example of  FIG. 4 , conductive structures  38  in antenna resonating element  36 B have the shape of an inverted-F antenna resonating element. This is merely illustrative. Antenna resonating element  36 B may be formed using any suitable type of antenna resonating element structures. 
     A cross-sectional side view of a portion of device  10  is shown in  FIG. 5 . As shown in  FIG. 5 , housing  12  of device  10  may have walls such as rear housing wall structure  12 B and side housing wall structure  12 A. In the example of  FIG. 5 , side wall  12 A and rear wall  12 B are substantially planar and lie in perpendicular planes. This is merely illustrative. Housing  12  may have a side wall that curves smoothly and forms an extension of a rear wall or may have other suitable housing shapes. 
     In the illustrative configuration of  FIG. 5 , device  10  has a display such as display  14 . A cover layer such as cover layer  56  may be used in covering the surface (e.g., the front surface) of device  10 . This helps protect the components of display  14 . Cover layer  56  may be formed from a transparent material such as clear plastic, clear glass, or other suitable material and is sometimes referred to as display “cover glass.” In active region  20  under cover glass  56 , display  14  may actively display images for a user. In inactive region  28 , the active structures of display  14  (display module  14 ) are not present. To help hide internal device structures from view, inactive region  28  (e.g., the interior surface of cover layer  56 ) may be provided with an opaque masking layer such as opaque masking layer  60 . Opaque masking layer  60  may be formed from black ink, opaque plastic, or other suitable material that prevents the interior of device  10  under masking layer  60  from being viewed from the exterior of device  10 . 
     Cavity antenna  36  may be mounted within the interior of housing  12  and device  10  so that cavity opening  42  (and the antenna resonating element that lies within cavity opening  42 ) is not blocked by conductive structures in display  14  and/or housing  12 . With the illustrative configuration of  FIG. 5 , opening  42  has been mounted under cover glass  56  within inactive display region  28 . During operation, radio-frequency signals for antenna  36  may pass through opaque masking layer  60  and the portion of cover glass  56  in region  28 . Because the sidewalls of cavity antenna  36  are conductive and serve as antenna ground structures, the performance of cavity antenna  36  will be relatively insensitive to manufacturing variations in the distance between antenna  36  and adjacent conductive structures such as conductive housing structures  12  (e.g., conductive housing walls in configurations where housing  12  is formed from metal), conductive structures in display  14 , and conductive structures in other internal device components  58  (e.g., integrated circuits, housing frame structures, connectors, other internal device components, etc.). In the example of  FIG. 5 , cavity opening  42  has been mounted under a portion of cover layer  56 . In general, cavity opening  42  may mounted under any desired dielectric structure in device  10 . 
     As shown in  FIG. 5 , bend  46  allows the length and therefore the total volume of cavity antenna  36  to be enlarged without being constrained by the limited thickness of device housing  12  and device  10 . In particular, bend  46  allows portion  50  of the antenna cavity to be extended under conductive internal device components such as the conductive structures associated with display  14 , thereby enlarging the size of cavity antenna  36  without undesirably increasing thickness T of device  10 . 
       FIG. 6  is a cross-sectional side view of device  10  in a configuration in which housing  12  has curved walls extending from a front surface where edge  12 E of housing wall  12  meets cover glass layer  56  to a rear planar surface  12 R. Cavity antenna  36  may have a curved shape that allows the volume of the cavity antenna  36  to extend under and around internal device components such as display  14  and other internal components  58 . This allows the volume of the cavity to be expanded without increasing the thickness T of device  10 . 
       FIG. 7  is a perspective view of an illustrative antenna cavity having a T shape. As shown in  FIG. 7 , antenna cavity  36 A may have a straight cavity portion such as portion  62 . Opening  42  may be formed at one end of straight cavity portion  62 . Opening  42  may have edges  44  in the shape of a rectangle or other suitable cavity opening shape. An antenna resonating element such as antenna resonating element  36 B of  FIG. 4  may be mounted within opening  42 . Cavity  36 A may have branching portions such as cavity extensions  64 . Cavity portions  64  may, for example, be perpendicular to straight portion  62 , so that the cavity  36 A has a T shaped when viewed from side (end) direction  66 . 
       FIG. 8  is a cross-sectional side view of a portion of an electronic device having a T-shaped cavity antenna such as an antenna with a T-shaped cavity such as cavity  36 A of  FIG. 7 . As shown in  FIG. 8 , cavity  36 A may be oriented so that opening  42  (and the antenna resonating element  42  within opening  42 ) is mounted under a dielectric material such as cover layer  56  or a dielectric antenna window formed from a plastic structure of other dielectric structure that is mounted in an opening in conductive housing  12 . Cavity extensions  64  may be used to expand the volume of cavity  36 A without increasing thickness T of device  10 . Extensions  64  may protrude under electrical components in the interior of device  10  such as components  58 . With this type of arrangement, components such as components  58 , other conductive internal device components such as display  14 , and other conductive materials may be mounted between portions of cavity  36 A and portions of cover glass  56  or other structures on the surface of device  10 , thereby allowing cavity  36 A to be mounted in devices with constrained layouts. 
     If desired, components  58  may be interposed within openings formed between respective portions of antenna cavity  36 A. This type of configuration is shown in  FIG. 9 . As shown in  FIG. 9 , antenna cavity  36 A may have first and second branches  68 . Internal device components such as component  58  may be interposed between first and second branches  68 . In configurations for cavity  36 A in which portions  68  of cavity  36 A surround conductive device components such as illustrative electrical device component  58  of  FIG. 9 , cavity volume may be maximized while accommodating desired component mounting locations. 
     Cavity  36 A may have shapes with sides that are not planar. As shown in  FIG. 10 , for example, antenna cavity  36 A may have a shape with curved sides such as a tube with one open end and one closed end. The sides of antenna cavity  36 A may form a tubular shape with one branch (as shown in  FIG. 10 ), a shape with multiple tubular branches, or other shapes with curved sides. If desired, cavity  36  may have a combination of curved and planar sides. 
     As shown in the cross-sectional side view of illustrative antenna cavity  36 A of  FIG. 11 , antenna cavity  36 A may have a T-shape with unequally sized branches. In the  FIG. 11  example, branch  70  is shorter than branch  72 . 
     The  FIG. 12  example shows how T-shaped antenna cavity  36 A may be formed using equally sized branches  74  and  76 . 
     As shown in  FIG. 13 , antenna cavity  36 A may have a bend so that portion  78  follows an axis (axis  80 ) that is oriented at a non-zero angle A with respect to main cavity axis  82 . 
     With the illustrative configuration for antenna cavity  36 A that is shown in  FIG. 14 , bend  90  causes portion  84  to be angled with respect to the portion of cavity  36 A that includes opening  42 . Branches  86  and  88  may extend at different angles from portion  84 . 
     Curved antenna cavity  36 A may be characterized by bend radius R. To ensure that cavity  36 A operates as a satisfactory antenna cavity, it may be desirable to configure the curved walls of antenna cavity  36 A so that bend radius R is at least a quarter or a half of a wavelength at a desired operating frequency (as an example). 
     As shown in  FIG. 16 , branches  92  of T-shaped antenna cavity  36 A may have curved wall portions  92 . 
       FIG. 17  is a cross-sectional side view of an illustrative cavity having multiple chambers. In the configuration of  FIG. 17 , antenna cavity  36 A has two chambers  96 , which are coupled in series. Configurations with different numbers of chambers and chambers that branch off of a common cavity portion (e.g., parallel chambers) may also be used, if desired. 
     To conserve space within device  10  it may be desirable to form antenna cavity  36 A using structures that serve multiple functions. For example, antenna cavity  36 A may be formed, at least partly, using cavity structures that serve acoustic functions, structural functions, functions associated with forming connector ports, or other functions in device  10 . 
     Antenna cavity  36 A may, as an example, be implemented by forming conductive walls  40  on the sides of a chamber that is used in forming a speaker (i.e., a speaker box). This type of configuration is shown in  FIG. 18 . As shown in  FIG. 18 , structures  98  may have walls  40  that form a cavity structure for antenna cavity  36 . Walls  40  may be formed from metal, from metal mounted on a support structure such as a plastic support structure, or other cavity structures. A speaker diaphragm such as diaphragm  106  may be mounted within the interior volume of cavity  36 A. Speaker driver  104  may be provided with audio signals using paths  100  and terminals  102 . An acoustically transparent cover such as mesh  114  may be placed over opening  42  in cavity  36 A so that opening  42  serves as both a cavity antenna opening and a speaker port (opening) that allows sound to exit the interior volume of the speaker. 
     Antenna resonating element  36 B may be mounted behind an acoustically transparent and radio-frequency transparent cover structure such as mesh  114  using a mounting structure such as mounting structure  112 . Mounting structure  112  may be formed from plastic (e.g., an integral portion of the plastic that forms supporting structures for walls  40 ) or other materials. Resonating element  36 B may have a smaller area than the area of opening  42 , to allow sound that is produced by driving diaphragm  106  to exit the speaker. Antenna terminals  118  may be coupled to positive antenna feed and ground antenna feed terminals on antenna resonating element  36 B. By combining both antenna cavity and speaker volume functions into structure  98 , the overall size of device  10  can be minimized. 
     A cross-sectional side view of the combined speaker and antenna cavity structure of  FIG. 18  taken along line  110  and viewed in direction  108  is shown in  FIG. 19 . As shown in  FIG. 19 , antenna resonating element  36 B may be mounted within the interior of antenna cavity  36 A in opening  42 . Antenna resonating element  36 B may, as an example, be mounted behind acoustic mesh  114 . Structures that include both cavity antenna structures and speaker structures of the type shown in  FIGS. 18 and 19  may be formed using any suitable cavity shape (see, e.g., cavity shapes of the type shown in  FIGS. 11-17 ). 
     As shown in the example of  FIG. 20 , cavity  36 A (e.g., an antenna cavity or a chamber that serves both antenna cavity and speaker box functions) may have multiple bends along its length such as bends  120  and  122 .  FIG. 21  is a top view of device  10  showing how a cavity shape of the type shown in  FIG. 20  may be used to allow cavity  36 A to be routed past internal components  58  so that the volume of cavity  36 A may be maximized. In the example of  FIGS. 20 and 21 , cavity  36 A has a length with two bends. If desired, more than two bends may be formed along the length of cavity  36 A or the length of cavity  36 A may be provided with fewer bends or bends of different shapes. 
     Cavity walls such as cavity walls  40  of antenna cavity  36 A may be formed from sheets of metal (e.g., stamped metal foil), from cast or machined metal, from patterned traces on printed circuit board substrates, using metal that is deposited onto a plastic carrier using electrochemical deposition or physical vapor deposition, using metal deposited on one or two shots of molded thermoplastic (e.g., a molded interconnect device) or any other suitable conductive materials. Techniques such as these may also be used in forming conductive structures for antenna resonating element  36 B in cavity antenna  36 . 
     With one suitable arrangement, laser patterning may be used in forming conductive antenna structures. Laser patterning processes may use thermoplastic materials that can be locally sensitized by exposure to laser light. Once sensitized, electroplating may be used to deposit additional metal and thereby form a desired pattern of conductive antenna structures. Laser patterning techniques of this type are sometimes referred to as Laser Direct Structuring (LDS). Tools for performing these techniques are available from LPFK Laser &amp; Electronics AG of Garbsen, Germany. 
     Use of an illustrative laser patterning technique in forming an antenna resonating element and subsequent steps involved in attaching the antenna resonating element to a conductive antenna cavity are shown in  FIG. 22 . As shown in  FIG. 22 , the relative position between laser  124  and substrate  128  may be controlled using one or more positioners such as positioner  130 . Positioners such as positioner  130  may be implemented using computer-controlled translation stages or other computer-controlled actuators. Substrate  128  may be a dielectric substrate (e.g., a plastic substrate) with a composition that allows sensitization upon exposure to laser light). 
     After moving laser beam  126  over the surface of substrate  128 , metal may be added to the sensitized portions of substrate  128  using electrochemical deposition (e.g., electroplating) to form antenna resonating element traces  132 . 
     Conductive cavity walls  40  for antenna cavity  36 A may be formed by using stamping tool  138  to form a conductive material such metal sheet  134  into a desired cavity shape or other techniques may be used in forming conductive cavity walls  40 . Solder  136  (e.g., a bead of solder paste) may be formed around the periphery of opening  42  in cavity  36 A (i.e., on some or all of edges  44 ). After placing antenna resonating element  36 B in opening  42 , antenna  36  may be placed in solder reflow oven  140  or may otherwise be exposed to heat (e.g., from a heat gun, laser, etc.). The heat may cause the solder paste to reflow and form solder joints  136  around some or all of the edges of antenna resonating element  36 B (e.g., portions of the edge of cavity opening  42  where the conductive material of the antenna resonating element is present). As shown in the lower portion of  FIG. 22 , solder  136  may connect conductive structures  38  on antenna resonating element  36 B around peripheral portions of cavity opening  42  (i.e., along at least some of peripheral edge  44 ) to the conductive material of cavity walls  40  of cavity  36 A. Structures  38  may, in general, extend around some or all of the periphery of antenna resonating element  36 B. Conductive adhesive, non-conductive adhesive, welds, screws, and other mechanical and/or electrical attachment techniques may also be used in connecting conductive structures in opening  42  such as antenna resonating element  36 B to antenna cavity  36 A in addition to or instead of using solder. 
     Antenna resonating element  36 B may have an inverted-F shape, a planar inverted-F shape, a closed or open slot antenna shape, a loop antenna shape, an L-shape or T-shape, a horn antenna shape, or any other suitable antenna shape.  FIG. 23  is a perspective view of an illustrative antenna resonating element shape in which antenna resonating element  36 B has been formed from conductive antenna traces  38  that form a slot antenna shape with an opening (slot  142 ) on substrate  128 . The slot antenna configuration for antenna resonating element  36 B of  FIG. 23  is merely illustrative. Antenna resonating elements for cavity-backed antenna  36  may have any suitable configuration. 
       FIG. 24  shows how a substrate for antenna resonating element  36 B may be formed using a two-shot molding technique. With this type of arrangement, first substrate portion  146  may be formed using a first thermoplastic molding process implemented using molding tool  144 . A second substrate portion such as portion  150  may then be molded to the first portion using molding tool  148 . Portion  146  may have an affinity for metal deposition during exposure to electrochemical deposition processes (e.g., during electroplating), whereas portion  150  may be resistant to metal deposition. During metal plating operations using plating tool  152 , metal will therefore be deposited in region  146  to form metal antenna traces  38  for antenna resonating element  36 B, as shown in the lower portion of  FIG. 24 . 
     Use of two different types of thermoplastic in a two step molding process of the type shown in  FIG. 24  is sometimes referred to as a “two-shot” molding process. Portion  146  may be referred to as a first shot of plastic and portion  150  may be referred to as a second shot of plastic. The resulting substrate that is formed may be referred to as a two-shot plastic substrate. Because the first and second shots of material have different metal deposition affinities, metal tends to build up selectively during electroplating, allowing the formation of desired antenna resonating element trace patterns on antenna resonating element  36 B. Antenna resonating elements formed with traces that are deposited using two-shot molding and electroplating techniques or any other suitable selective metal deposition scheme may be soldered to antenna cavity  36 B using soldering arrangements of the type shown in  FIG. 22  or may be attached to antenna cavity  36 B using other attachment mechanisms (conductive adhesive, welds, etc.), if desired. 
     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: 20110830
Publication Date: 20160927
Grant Date: 20160927
Priority Date: 20110830
Inventors: SHIU BOON W.
BEVELACQUA PETER
ZHU JIANG
GUTERMAN JERZY
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q1/24", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/44", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q13/18", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/2258", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/2258", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/24", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q13/18", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/44", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 47742899