Patent Application
20170062906
This relates generally to electronic devices and, more particularly, to electronic devices with wireless communications circuitry.
Electronic devices often include wireless circuitry with 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 electrical components and conductive structures in the device can influence antenna performance. Antenna performance may not be satisfactory if conductive structures and electrical components in a device 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.
An electronic device may have wireless circuitry with antennas. The electronic device may have a dielectric housing. A printed circuit board with electrical components may be mounted in the dielectric housing. Heat spreader structures that are used to dissipate heat from the electrical components may also be mounted in the housing.
The heat spreader structures may include a metal heat spreader from which corner portions have been removed to form antenna cavities. The antennas in the electronic device may each be formed from an antenna resonating element and one of the antenna cavities. Antennas may be located at the corners of the electronic device housing. The antennas may handle wireless local area network signals or other wireless signals.
An electrical component such as a light-emitting diode may be mounted in one of the antenna cavities. Each antenna may have an inverted-F antenna resonating element with short and long arms to support dual band operation. The short arm of each antenna resonating element may be formed from edge plated metal traces on an edge of the printed circuit. The long arm may lie between a rear wall of the antenna cavity and the short arm.
Electronic devices such as electronic device 10 of
Electronic device 10 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 handheld device such as a cellular telephone, a media player, or other small portable device. Device 10 may also be a set-top box, a desktop computer, a display into which a computer or other processing circuitry has been integrated, a display without an integrated computer, or other suitable electronic equipment. As an example, device 10 may be a set-top box or computer that has a rectangular or square housing and that is coupled to a computer monitor, television, or other display.
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. Parts of housing 12 (e.g., an outer housing shell) may be formed from walls of dielectric or other low-conductivity material. Housing 12 or other structures in device 10 (e.g., heat sink structures, internal housing structures, etc.) may also be formed from metal. The footprint of device 10 (i.e., the shape of housing 12 when viewed from above) may be rectangular, square, or other suitable shape. The shape of housing 12 may be cubic, rectangular box-shaped, or may have other suitable shapes.
To handle wireless communications, device 10 may contain one or more antennas. The antennas can include loop antennas, inverted-F antennas, strip antennas, planar inverted-F antennas, slot antennas, hybrid antennas that include antenna structures of more than one type, or other suitable antennas.
In general, device 10 may include any suitable number of antennas (e.g., one or more, two or more, three or more, four or more, etc.). The antennas in device 10 may be located at the corners of housing 12 (see, e.g., corners 14 and 16), may be located along one or more edges of a device housing, may be formed in the center of housing 12, or may be located in other suitable locations.
A schematic diagram showing illustrative components that may be used in device 10 of
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, multiple-input and multiple-output (MIMO) protocols, antenna diversity protocols, etc.
Input-output circuitry 30 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 32 may include touch screens, displays without touch sensor capabilities, buttons, joysticks, 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, position and orientation sensors (e.g., sensors such as accelerometers, gyroscopes, and compasses), capacitance sensors, proximity sensors (e.g., capacitive proximity sensors, light-based proximity sensors, etc.), fingerprint sensors, etc.
Input-output circuitry 30 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 circuitry that handles 2.4 GHz and 5 GHz bands for WiFi® (IEEE 802.11) communications and that handles the 2.4 GHz Bluetooth® communications band. If desired, wireless communications circuitry 34 may also include additional transceiver such as cellular telephone transceiver circuitry or other remote wireless circuitry 38 and satellite navigation system circuitry such as Global Positioning System (GPS) circuitry 42. Wireless communications circuitry 34 can also include 60 GHz transceiver circuitry or other extremely high frequency communications circuitry, circuitry for receiving television and radio signals, paging system transceivers, near field communications (NFC) circuitry, etc. 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. Antennas 40 may be single band antennas, dual band antennas, or antennas that resonate in more than three communications bands. As an example, antennas 40 may handle wireless local area network communications in a single communications band such as a communications band at 2.4 GHz or may handle communications in multiple bands (e.g., a 2.4 GHz band and a 5 GHz band).
An illustrative antenna for device 10 that is coupled to a transceiver circuit is shown in
Transmission line path 92 of
Transmission line 92 may be coupled to antenna feed structures associated with antenna 40 such as feed 112. Inverted-F antenna 40 of
Main resonating element arm 108 may be coupled to ground 104 by return path 110. An inductor or other component may be interposed in path 110 and/or tunable components may be interposed in path 110 and/or coupled in parallel with path 110 between arm 108 and ground 104.
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 resonating element 106 and ground 104. If desired, inverted-F antennas such as illustrative antenna 40 of
In the example of
Antenna 40 may be formed from metal traces on a printed circuit board and other conductive structures in device 10. With one suitable arrangement, which may sometimes be described herein as an example, resonating element 106 may be formed from patterned metal traces on a printed circuit board, whereas ground 104 may be formed from a metal antenna cavity structure that is shorted to ground traces on the printed circuit board. The metal cavity structure may, as an example, be formed from a cavity in a metal device structure such as a metal heat spreader (e.g., a heat sink).
A cross-sectional side view of an illustrative printed circuit and associated heat spreader (thermal spreader) structures of the type that may be used in device 10 is shown in
Antennas for device 10 may be formed in the corners of housing 12, as described in connection with illustrative corners 14 and 16 of
If desired, one or more electrical components such as electrical component 172 may be mounted within cavity 170. Component 172 may be an integrated circuit, sensor, or other circuitry for device 10 (see, e.g., circuitry 28 and 30 of
Metal traces for antenna resonating element 106 may be formed on peripheral edge 154E of printed circuit 154 in order to maximize the separation between these metal traces and antenna ground 104 and thereby enhance antenna bandwidth. If desired, edge plating (electroless or electrolytic plating) techniques may be used to form metal traces for antenna 40 on the side of printed circuit 154. As shown in
Antenna resonating element 106 may have a longer arm such as arm 108 that lies within the middle of the area shadowed by cavity 170 and a shorter arm such as arm 108′ that is formed from edge plated metal on edge 154E of printed circuit 154. Arm 108 may allow antenna 40 to resonate in a first communications band (e.g., at a frequency of 2.4 GHz) and arm 108′ may allow antenna 40 to resonate in a second communications band (e.g., at a frequency of 5 GHz). Return path 110 may couple antenna resonating element 106 to ground. The higher frequency signals associated with arm 108′ may be more directional in nature than the lower frequency signals associated with arm 108, so antenna performance may be enhanced by placing arm 108′ at a location that is farther from the rear cavity wall of cavity 170 and ground traces 170M than arm 108.
Cavity 170 and associated ground traces 170M may have a shape that accommodates electrical component 172 (e.g., a light-emitting diode). To electrically isolate component 172 and antenna 40, device 10 may be provided with an isolation circuit of the type shown in
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.
