Patent Application
20130293424
This relates generally to electronic devices, and, more particularly, to antennas in electronic devices.
Electronic devices such as portable computers and handheld electronic devices are becoming increasingly popular. Devices such as these are often provided with wireless communications capabilities. For example, electronic devices may use long-range wireless communications circuitry to communicate using cellular telephone bands. Electronic devices may use short-range wireless communications links to handle communications with nearby equipment.
It can be difficult to incorporate antennas, audio components, and other electrical components successfully into an electronic device. Some electronic devices are manufactured with small form factors, so space for components is limited. In many electronic devices, the presence of conductive structures can influence the performance of electronic components such as antennas, further restricting potential mounting arrangements.
It would therefore be desirable to be able to provide improved ways in which to incorporate components such as antennas in electronic devices.
An electronic device may have a housing in which one or more antennas may be formed. The electronic device may have a display with a display cover layer. The display cover layer may be mounted in the electronic device. Corner brackets may be located at the corners of the device to support the display cover layer.
A slot antenna may be used to handle wireless communications. The slot antenna may be formed from an opening in the corner bracket, patterned metal traces on a hollow plastic support structure, or other conductive structures. An antenna cavity for the slot antenna may be formed from traces on the plastic support structure or other cavity structures.
The slot antenna may have a main portion with opposing ends. An antenna feed may be located at one of the ends. The slot antenna may have a closed slot with one or more bends. The bends may provide the slot antenna with a C-shaped outline. A side branch slot may extend laterally outwards from the main portion of the slot at a location between the two bends and may operate as an open slot. The presence of the side branch slot may enhance antenna bandwidth. A hollow enclosure may serve as an antenna support structure and as a speaker box enclosing a speaker driver. The antenna feed may be positioned so as to overlap the speaker driver to minimize disruption to antenna performance due to the presence of the speaker driver.
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.
Electronic devices may be provided with antennas, audio components such as speakers, and other electronic components. It may be desirable to form some of these components in compact device configurations. For example, it may be desirable to form components for electronic devices using portions of housing structures, from structures that allow an antenna and another component to share mounting structures, and using antenna layouts that accommodate small form factor devices while exhibiting satisfactory wireless performance.
In some situations, it may be desirable to form conductive antenna structures that have slots. For example, slot antennas for cellular telephone communications, wireless local area network communications (e.g., WiFi® and Bluetooth® communications), and other wireless communications bands may be formed using conductive structures in which slot-shaped openings have been formed. To ensure that electronic components such as antenna and audio structures can be mounted satisfactorily within a desired device, slot-based antennas may be formed that are constructed as part of a structural housing element such as a corner bracket or other internal housing structure. Multiple slot arms may be included in a slot antenna to ensure sufficient wireless bandwidth. Some slot antenna structures may be mounted within a device in the vicinity of an electrical component such as a speaker having a speaker driver mounted in speaker box. These slot antenna structures may have a slot antenna feed that overlaps the speaker driver to minimize interference between the speaker and antenna.
An illustrative electronic device in which electronic component mounting schemes such as these may be used is shown in
As shown in
Housing 12 may be formed from conductive materials such as metal (e.g., aluminum, stainless steel, etc.), carbon-fiber composite material or other fiber-based composites, glass, ceramic, plastic, other materials, or combinations of these materials. Antenna and speaker structures for device 10 may be formed along edges such as edge 58, at corners such as corner 57, or elsewhere within housing 12.
Device 10 may have user input-output devices such as button 59. Display 50 may be a touch screen display that is used in gathering user touch input. The surface of display 50 may be covered using a transparent dielectric member such as a planar cover glass member or a planar clear layer of plastic. The central portion of display 50 (shown as region 56 in
A layer of material such as opaque ink, plastic, or other opaque masking layer material may be placed on the underside of display 50 in peripheral region 54 (e.g., on the underside of the display cover layer). This opaque masking layer may be transparent to radio-frequency signals. Conductive touch sensor electrodes in region 56 may tend to block radio-frequency signals. However, radio-frequency signals may pass through the display cover layer and the opaque layer in inactive display region 54 (as an example). Radio-frequency signals may, if desired, also pass through dielectric housing wall structures or other dielectric structures in device 10.
With one suitable arrangement, housing 12 may be formed from a metal such as aluminum. Portions of housing 12 may form ground structures (e.g., an antenna ground plane). Antenna ground structures may also be formed from traces on antenna support structures, metal tape, conductive fabric, printed circuit traces, and other conductive structures in device 10.
A cross-sectional view of device 10 taken along line 1300 of
The antenna resonating element formed from structures 80 may be based on any suitable antenna resonating element design (e.g., structures 80 may form a patch antenna resonating element, a single arm inverted-F antenna structure, a dual-arm inverted-F antenna structure, other suitable multi-arm or single arm inverted-F antenna structures, a closed and/or open slot antenna structure, a loop antenna structure, a monopole, a dipole, a planar inverted-F antenna structure, a hybrid of any two or more of these designs, etc.). With one suitable arrangement, which may sometimes be described herein as an example, antenna structures 80 may be based on a slot antenna design with an optional antenna cavity (i.e., antenna structures 80 may form a cavity-backed slot antenna). Housing 12 and conductive structures in antenna structures 80 such as cavity sidewall structures may serve as antenna ground for an antenna formed from structure 80 and/or other conductive structures within device 10 may serve as ground (e.g., conductive components, traces on printed circuits, etc.).
As shown in
Antenna structures 80 may be formed from conductive structures that are mounted adjacent to or on top of support structures 84. For example, antenna structures 80 may include conductive material such as conductive layers 86, 90, and 88 or other conductive structures. Conductive layers 86, 90, and 88 may be formed from layers of metal formed on the surfaces of support structures 84, from flexible or rigid printed circuits, conductive fabric, conductive foam, metal foil, metal formed on plastic parts using lasers and other tools, or other structures that are attached to support structures 84 using adhesive, from metal housing structures, from portions of electronic components, or other conductive structures. Structures 86 and 90 may form cavity walls for an antenna cavity (e.g., walls that form an open-toped box cavity that is covered by structures 88).
Structures 86 and 90 may be formed on support structure 84 by plating metal onto the surface of structure (as an example). If desired, structures 90 may be formed from a metal wall (e.g., a sheet of metal, a fabric layer, or a metal coating on structures 84). Solder, conductive foam, or other conductive material 81 may be used to ground structures 90 to display structures 64. Metal layer 88, which may form a ground plane (conductive plane) in which slot openings are formed for a slot antenna resonating element, may be formed from patterned metal traces on a planar upper surface of antenna support structures 84, from a flexible printed circuit or other printed circuit, from stamped metal foil, or from other conductive structures. If desired, other types of conductor arrangements may be used in forming the conductive materials for antenna structures 80. The illustrative configuration of
During operation of the antenna formed from structures 80, radio-frequency antenna signals can be conveyed through a display cover member such as cover layer 60 in directions 70. Display cover layer 60 may be formed from one or more clear layers of glass, plastic, or other materials.
Display 50 may have an active region such as region 56 in which cover layer 60 has underlying conductive structure such as display panel module 64. The structures in display panel 64 such as touch sensor electrodes and active display pixel circuitry may be conductive and may therefore attenuate radio-frequency signals. In region 54, however, display 50 may be inactive (i.e., panel 64 may be absent). An opaque layer such as plastic or ink 62 may be formed on the underside of transparent cover glass 60 in region 54 to block the antenna resonating element that is formed from structures 88 from view by a user of device 10. Opaque material 62 and the dielectric material of cover layer 60 in region 54 may be sufficiently transparent to radio-frequency signals that radio-frequency signals can be conveyed through these structures in directions 70.
Device 10 may include one or more internal electrical components such as components 23. Components 23 may include storage and processing circuitry such as microprocessors, digital signal processors, application specific integrated circuits, memory chips, and other control circuitry. Components 23 may be mounted on one or more substrates such as substrate 79 (e.g., rigid printed circuit boards such as boards formed from fiberglass-filled epoxy, flexible printed circuits, molded plastic substrates, etc.). Components 23 may include input-output circuitry such as audio circuitry (e.g., circuitry for playing sound through speakers), sensor circuitry, button control circuitry, communications port circuitry, display circuitry, wireless circuitry such as radio-frequency transceiver circuitry (e.g., circuitry for cellular telephone communications, wireless local area network communications, satellite navigation system communications, near field communications, and other wireless communications), and other circuits. Connectors may be used in interconnecting circuitry 23 to transmission line paths. The transmission line paths may be used to route signals between the transceiver circuitry in components 23 and antenna structures 88.
Slot 92 may have an inner perimeter (i.e., a perimeter that is about equal to twice the slot's length). The size of the inner perimeter may be configured to be substantially equal to one wavelength at a fundamental operating frequency of interest. Harmonics, cavity modes, and other factors may allow antenna 80 to cover additional frequencies of interest.
To help accommodate slot 92 within device 10, slot 92 may have a meandering path (e.g., a path with one or more bends). As an example, slot 92 may have a C-shape. With this type of configuration, slot 92 may have a main portion such as main segment 100 and one or more end portions (segments) such as perpendicular end branches 102. Slot 92 may also have end portions (segments) such as branches 104 that run parallel to main branch 100 at the opposing ends of the slot.
As shown in
A cross-sectional view of antenna structures 80 taken along line 106 and viewed in direction 108 of
To ensure satisfactory bandwidth in desired communications bands during operation of slot antenna 80, slot antenna 80 may, if desired, be provided with additional branches. Consider, as an example, slot antenna 80 of
Slot 92 may be characterized by a length such as length L1. The width of slot 92 (i.e., the lateral dimension of slot 92 transverse to length L1), may be relatively small relative to length L1 (i.e., W may be a fifth of L1 or less, a tenth of L1 or less, etc.). In this type of configuration, the length L1 may be approximately one half of a wavelength at an operating frequency of interest. In addition to the main body of slot 92 (i.e., the rectangular slot of length L1 in the example of
The main body of slot 92 has closed ends 104, so a slot such as slot 92 of
Side branch slot 114 may help to broaden the frequency response of antenna 80. An illustrative graph of antenna performance for an antenna such as antenna 80 of
Antenna structures 80 of
A cross-sectional side view of device 10 in the vicinity of antenna structures 80 that include a slot such as slot 92 in housing structure 124 is shown in
A transmission line such as transmission line 134 may be coupled to antenna feed 94. Antenna feed 94 may be located at one of the ends of slot 92 to help impedance match transmission line 134 and antenna 80. Transmission line 134 may have a positive signal conductor that is coupled to positive antenna feed terminal 96 and a ground signal conductor that is coupled to ground antenna feed terminal 98. Transmission line 134 may be formed from a coaxial cable, a flexible printed circuit with signal line traces, a microstrip transmission line structure, a stripline transmission line structure, or other transmission line structure. Transmission line 134 may be used in conveying signals between antenna 80 and radio-frequency transceiver circuitry in components 23 (
Display cover layer 60 may be supported by the upper surface of bracket 124. Adhesive may be used to attach display cover layer 60 to bracket 124, if desired. Screws such as screw 132 and/or adhesive 130 or other attachment mechanisms may be used in attaching bracket 124 to housing 12.
If desired, some of the interior volume of device 10 may be used to form a cavity for cavity antenna 80 while simultaneously being used to form a speaker box (speaker cavity) for a speaker. As shown in
Enclosure 136 may also contain a speaker driver such as speaker driver 138. Speaker driver 138 may include an actuator such as actuator 142 (e.g., a solenoid or other electromechanical actuator). Actuator 142 may be coupled to diaphragm 140 by support structure 158. Audio signals may be provided to driver terminals 144 and 146 by signal lines 148 and 150, respectively. When it is desired to play sound for a user of device 10, the signals that are provided to driver 142 via the signal path formed from lines 148 and 150 can be used to cause actuator 142 to move diaphragm 140. The movement of diaphragm 140 creates sound that may pass through the port formed by opening 156 in enclosure 136 and opening 154 in housing 12.
If desired, antenna 80 of
The size of speaker driver 138 may serve as a metric for measuring the location of antenna feed 94 relative to speaker driver 138. Speaker driver 138 may contain conductive components such as metal parts associated with actuator 158 and other structures. Electric field strength associated with the operation of antenna 80 may be minimized in the vicinity of end of slot 92 and therefore the antenna feed at the end of slot 92. It may therefore be desirable to locate the feed for antenna 80 (i.e., the end of the slot) in the vicinity of speaker driver 138, so as not to disrupt antenna operation with the presence of metal structures in speaker driver 138. The feed for antenna 80 (and the end of the slot) may be considered to be located in the vicinity of driver 138 when the feed (e.g., both of the feed terminals in the feed) or slot end falls within a radius of W, 2W, or 3W of speaker driver 138 (as examples).
A top view of a portion of electronic device 10 showing how antenna feed 94 may be configured to overlap speaker driver 138 (or otherwise be located in the vicinity of speaker driver 138). As shown in
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.
