Patent Application
20120223866
This relates generally to antennas, and, more particularly, to antennas for electronic devices.
Electronic devices such as portable computers and handheld electronic devices are often provided with wireless communications capabilities. For example, electronic devices may use long-range wireless communications circuitry such as cellular telephone circuitry and short-range communications circuitry such as wireless local area network communications circuitry. Some devices are provided with the ability to receive other wireless signals such as Global Positioning System signals.
It can be difficult to incorporate antennas successfully into an electronic device. Some electronic devices are manufactured with small form factors, so space for antennas is limited. In many electronic devices, the presence of electronic components in the vicinity of an antenna serves as a possible source of electromagnetic interference. Antenna operation can also be disrupted by nearby conductive structures. Considerations such as these can make it difficult to implement an antenna in an electronic device that contains conductive housing walls or other conductive structures that can potentially block radio-frequency signals.
It would therefore be desirable to be able to provide improved antennas for wireless electronic devices.
Antennas may be provided for electronic devices such as portable computers. A flexible antenna resonating element substrate may be wrapped around a dielectric carrier. The dielectric carrier may have first and second opposing surfaces that are covered by the wrapped substrate. The first surface may be a planar surface that is mounted against a display cover glass layer. The second surface may be a curved surface having a shape that matches a curved dielectric antenna window shape in a curved portion of the housing of an electronic device.
The flexible antenna resonating element substrate may have a first antenna resonating element at one end and a second antenna resonating element at an opposing end. Conductive structures such as conductive housing structures may form antenna ground. The first antenna resonating element and the antenna ground may form a first antenna such as a cellular telephone antenna or other suitable antenna.
The second antenna resonating element and the antenna ground may form a second antenna such as a satellite navigation system antenna or other suitable antenna.
A parasitic antenna resonating element may form part of the first antenna. The first antenna may be configured to operate in first and second communications bands. The parasitic antenna resonating element may be used to ensure that the antenna covers the second communications band.
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 wireless communications circuitry. The wireless communications circuitry may be used to support wireless communications in one or more wireless communications bands. For example, the wireless communications circuitry may transmit and receive signals in cellular telephone bands and other communications bands and may receive wireless signals in satellite navigation system bands.
Space is at a premium in electronic devices such as portable electronic devices. Housings for these devices are sometimes constructed from conductive materials that block antenna signals. Arrangements in which antenna structures are formed behind a dielectric antenna window can help address these challenges. A dielectric window may be formed within an opening in the conductive housing wall. If desired, wireless signals can also be accommodate by forming all or most of an electronic device housing from a dielectric such as plastic. In some configurations, wireless signals can pass through dielectric structures such as the cover glass layers associated with a display. These configurations, other configurations for accommodating wireless signals in a device, or combinations of these configurations may be used in a wireless electronic device if desired.
Antenna resonating elements for antennas may be formed in the vicinity of an antenna window and under a portion of a display cover layer. Portions of a conductive housing or other conductive structures may serve as antenna ground. The antenna can be fed using a positive antenna feed terminal that is coupled to the antenna resonating element and a ground antenna feed terminal that is coupled to the conductive housing. During operation, radio-frequency signals for the antenna can pass through the antenna window and other non-conducting housing structures such as part of the cover glass.
The antennas may be formed from antenna resonating elements and conductive portions of the housing or other conductive structures that serve as antenna ground. The antenna resonating elements may be formed from conductive traces on a dielectric substrate. The conductive traces may be formed from copper or other metals. The dielectric substrate may be, for example, a flexible printed circuit. Flexible printed circuits, which are sometimes referred to as flex circuits, have conductive traces formed on a flexible dielectric substrate such as sheets of polyimide or other polymers.
The antenna resonating element substrate may be mounted on a support structure. For example, a flexible antenna resonating element substrate that includes multiple antenna resonating elements for multiple antennas may be wrapped around a dielectric carrier such as a molded plastic carrier or other plastic support structure. Wrapping the antenna resonating substrate around the carrier in this way allows the antennas to be efficiently mounted within a small available housing volume.
Antenna structures with configurations such as these can be mounted on any suitable exposed portion of a portable electronic device. For example, antennas can be provided on the front or top surface of the device. In a tablet computer, cellular telephone, or other device in which the front of the device is all or mostly occupied with conductive structures such as a touch screen display, it may be desirable to form at least part of the antenna window on a rear device surface. Other configurations are also possible (e.g., with antennas mounted in more confined locations, on device sidewalls, etc.). The use of antenna mounting locations in which at least part of a dielectric antenna window is formed in a conductive rear housing surface is sometimes described herein as an example, but, in general, any suitable antenna mounting location may be used in an electronic device if desired.
An illustrative portable device that may include antenna structures with resonating element substrates that are wrapped around a carrier is shown in
As shown in
Housings with straight sidewalls and other configurations may also be used. The front surface of device 10 (i.e., the cover of display 50) may sometimes be referred to as forming the front housing surface of device 12. The cover of display 50 may be formed from a layer of cover glass, a layer of plastic, or other materials. The cover layer for display 50 may be radio transparent in its inactive edge region (i.e., away from the conductive portions of the display that include active pixel circuits). As a result, radio-frequency signals may be received by antenna structures that are mounted under an edge portion of the display cover layer and may be transmitted from the antenna structures through the edge portion of the display cover layer. In configurations in which housing 12 is formed form a metal or other conductive material, a dielectric window such as dielectric window 58 may be formed in housing 12. Antenna structures for device 10 may be formed in the vicinity of dielectric window 58, so that radio-frequency antenna signals can pass through dielectric window 58 in addition to or instead of passing through the edge portions of the display cover layer.
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. Capacitive touch sensors or other touch sensors for the display may be implemented using a touch panel that is mounted under a planar cover glass member on the surface of display 50, may be integrated onto the cover glass layer, or may be otherwise incorporated into display 50. The central portion of display 50 (shown as region 56 in
Housing 12 may be formed from one or more structures. For example, housing 12 may include an internal frame and planar housing walls that are mounted to the frame. Housing 12 may also be formed from a unitary block of material such as a cast or machined block of aluminum. Arrangements that use both of these approaches may also be used if desired.
Housing 12 may be formed of any suitable materials including plastic, wood, glass, ceramics, metal, or other suitable materials, or a combination of these materials. In some situations, portions of housing 12 may be formed from a dielectric or other low-conductivity material, so as not to disturb the operation of conductive antenna elements that are located in proximity to housing 12. In other situations, housing 12 may be formed from metal elements. An advantage of forming housing 12 from metal or other structurally sound conductive materials is that this may improve device aesthetics and may help improve durability and portability.
With one suitable arrangement, housing 12 may be formed from a metal such as aluminum or stainless steel. Portions of housing 12 in the vicinity of antenna window 58 may serve as antenna ground. Antenna window 58 may be formed from a dielectric material such as polycarbonate (PC), acrylonitrile butadiene styrene (ABS), a PC/ABS blend, or other plastics (as examples). Window 58 may be attached to housing 12 using adhesive, fasteners, or other suitable attachment mechanisms. To ensure that device 10 has an attractive appearance, it may be desirable to form window 58 so that the exterior surfaces of window 58 conform to the edge profile exhibited by housing 12 in other portions of device 10. For example, if housing 12 has straight edges 12A and a flat bottom surface, window 58 may be formed with a right-angle bend and vertical sidewalls. If housing 12 has curved edges 12A, window 58 may have a similarly curved surface.
A schematic diagram of device 10 showing how device 10 may include one or more antennas 26 and transceiver circuits that communicate with antennas 26 is shown in
Input-output circuitry 14 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 18 such as touch screens and other user input interface are examples of input-output circuitry 14. Input-output devices 18 may also include user input-output devices such as buttons, joysticks, click wheels, scrolling wheels, touch pads, key pads, keyboards, microphones, cameras, etc. A user can control the operation of device 10 by supplying commands through such user input devices. Display and audio devices may be included in devices 18 such as liquid-crystal display (LCD) screens, light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), and other components that present visual information and status data. Display and audio components in input-output devices 18 may also include audio equipment such as speakers and other devices for creating sound. If desired, input-output devices 18 may contain audio-video interface equipment such as jacks and other connectors for external headphones and monitors.
Wireless communications circuitry 20 may include radio-frequency (RF) transceiver circuitry 23 formed from one or more integrated circuits, power amplifier circuitry, low-noise input amplifiers, passive RF components, one or more antennas, and other circuitry for handling RF wireless signals. Wireless signals can also be sent using light (e.g., using infrared communications).
Wireless communications circuitry 20 may include radio-frequency transceiver circuits for handling multiple radio-frequency communications bands. For example, circuitry 23 may include transceiver circuitry 22 that handles 2.4 GHz and 5 GHz bands for WiFi (IEEE 802.11) communications and the 2.4 GHz Bluetooth communications band. Circuitry 23 may also include cellular telephone transceiver circuitry 24 for handling wireless communications in cellular telephone bands such as the bands at 850 MHz, 900 MHz, 1800 MHz, and 1900 MHz, and 2100 MHz band (as examples). Wireless communications circuitry 20 can include circuitry for other short-range and long-range wireless links if desired. For example, transceiver circuitry 23 may include global positioning system (GPS) receiver equipment 21, wireless circuitry for receiving radio and television signals, paging circuits, 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 20 may include antennas 26 such as an antenna or antennas located adjacent to antenna window 58 and under the inactive peripheral portion 54 of display 50. Antennas 26 may be single band antennas that each cover a particular desired communications band or may be multiband antennas. A multiband antenna may be used, for example, to cover multiple cellular telephone communications bands. If desired, a dual band antenna may be used to cover two WiFi bands (e.g., 2.4 GHz and 5 GHz). A single band antenna may be used to receive satellite navigation system signals such as Global Positioning System signals at 1575 MHz (as an example). Different types of antennas may be used for different bands and combinations of bands. For example, it may be desirable to form a dual band antenna for forming a local wireless link antenna, a multiband antenna for handling cellular telephone communications bands, and a single band antenna for forming a global positioning system antenna (as examples).
Transmission line paths 44 may be used to convey radio-frequency signals between transceivers 23 and antennas 26. Radio-frequency transceivers such as radio-frequency transceivers 23 may be implemented using one or more integrated circuits and associated components (e.g., switching circuits, matching network components such as discrete inductors, capacitors, and resistors, and integrated circuit filter networks, etc.). These devices may be mounted on any suitable mounting structures. With one suitable arrangement, transceiver integrated circuits may be mounted on a printed circuit board. Paths 44 may be used to interconnect the transceiver integrated circuits and other components on the printed circuit board with antenna structures in device 10. Paths 44 may include any suitable conductive pathways over which radio-frequency signals may be conveyed including transmission line path structures such as coaxial cables, microstrip transmission lines, etc.
Antennas 26 may, in general, be formed using any suitable antenna types. Examples of suitable antenna types for antennas 26 include antennas with resonating elements that are formed from patch antenna structures, inverted-F antenna structures, closed and open slot antenna structures, loop antenna structures, monopoles, dipoles, planar inverted-F antenna structures, hybrids of these designs, etc. With one suitable arrangement, which is sometimes described herein as an example, part of housing 12 (e.g., the portion of housing 12 in the vicinity of antenna window 58) may form a ground structure for the antenna associated with window 58. Antenna ground structures may also be formed from conductive traces on printed circuit boards, internal housing members such as frame members and structural internal housing plates, conductive portions of components such as connectors, and other conductive structures.
A rear view of electronic device 10 in the vicinity of dielectric window 58 is shown in
At the lower portion of antenna window 58 in the example of
With one suitable arrangement, the antenna formed from antenna resonating element 64-3 may serve as a primary cellular telephone antenna for device 10 and antenna resonating element 64-1 may serve as a secondary cellular telephone antenna for device 10. The antenna formed from antenna resonating element 64-2 may serve as a satellite navigation system antenna such as a Global Positioning System antenna. This is merely illustrative. Antenna resonating elements 64-1, 64-2, and 64-3 and, if desired, additional antenna resonating elements in device 10 may be used in forming any suitable types of antennas.
Antennas 26 may be connected to transceiver circuitry 23 (e.g., cellular telephone transceiver circuitry, satellite navigation system receiver circuitry, etc.) using transmission line paths 44.
A cross-sectional side view of housing 12 of device 10 showing how antenna resonating element substrate 62A may be mounted under the surface of cover glass layer 68 in display 50 is shown in
The antenna resonating elements on substrate 62A (i.e., antenna resonating elements 64-1 and 64-2 of
Antenna resonating element substrate 62A may be wrapped around a dielectric carrier such as carrier 70. Carrier 70 may be formed from any suitable dielectric material (e.g., a plastic such as a liquid crystal polymer or other suitable dielectric). In housing configurations of the type shown in
A front perspective view of carrier 70 showing how the curved lower surface and the opposing planar upper surface of the carrier may meet along a common axis (axis 90) that runs along the peripheral upper edge of device 10 is shown in
Air-filled cavities in carrier 70 such as cavities 84 may facilitate formation of carrier 70 using injection molding techniques.
As shown in
At the opposing end of substrate 62A (i.e., the left-hand end in the configuration of
Parasitic antenna resonating element 94 may be formed from a strip of conductor (i.e., a patterned metal trace) that is electrically isolated from trace 64-1 on substrate 62A and that is not directly feed by one of transmission lines 44-1 and 44-2. One end of parasitic antenna resonating element 94 may be grounded to housing 12 (i.e., housing portion 12′ of
A graph of the response of the antennas formed using the antenna structures of
If desired, other types of antennas may be formed on substrate 62A. The illustrative arrangement of
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.
