Patent Grant
11139588
This relates generally to electronic devices and, more particularly, to electronic devices with wireless communications circuitry.
Electronic devices often include wireless communications circuitry. For example, cellular telephones, computers, and other devices often contain antennas and wireless transceivers for supporting wireless communications.
It may be desirable to support wireless communications in millimeter wave and centimeter wave communications bands. Millimeter wave communications, which are sometimes referred to as extremely high frequency (EHF) communications, and centimeter wave communications involve communications at frequencies of about 10-300 GHz. Operation at these frequencies may support high bandwidths, but may raise significant challenges. For example, millimeter wave communications signals generated by antennas can be characterized by substantial attenuation and/or distortion during signal propagation through various mediums and can generation undesirable surface waves at medium interfaces.
It would therefore be desirable to be able to provide electronic devices with improved wireless communications circuitry such as communications circuitry that supports millimeter and centimeter wave communications.
An electronic device may be provided with wireless circuitry. The wireless circuitry may include one or more antennas and transceiver circuitry such as centimeter and millimeter wave transceiver circuitry (e.g., circuitry that transmits and receives antennas signals at frequencies greater than 10 GHz). The antennas may be arranged in a phased antenna array.
The electronic device may include a housing having a dielectric cover layer. The phased antenna array may be formed on a dielectric substrate and may include conductive traces at a surface of the substrate. The conductive traces may form antenna resonating elements or parasitic elements for antennas in the phased antenna array. The surface of the substrate may be mounted against an interior surface of the dielectric cover layer (e.g., using a layer of adhesive). The dielectric cover layer may have a dielectric constant and a thickness that is selected so that the dielectric cover layer forms a quarter wave impedance transformer for the phased antenna array at a wavelength of operation of the phased antenna array. When configured in this way, signal attenuation and destructive interference within and below the dielectric cover layer may be minimized. The phased antenna array may convey radio-frequency signals through the dielectric cover layer with satisfactory antenna gain across all angles within the field of view of the phased antenna array.
The substrate may include fences of conductive vias that laterally surround each of the antennas within the phased antenna array. The fences of conductive vias and ground traces in the substrate may define conductive cavities for each antenna in the phased antenna array. The conductive cavities may serve to enhance the antenna gain of the phased antenna array (e.g., to mitigate signal attenuation within the dielectric cover layer). The fences of conductive vias may be arranged in a pattern of unit cells across the lateral area of the substrate. The unit cells may be arranged or tiled to conform to space requirements within the device and to mitigate surface wave propagation at points that are relatively far from the phased antenna array. The phased antenna array may include antennas and unit cells of different shapes for covering different frequencies if desired.
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, a wireless access point, wireless base station, an electronic device incorporated into a kiosk, building, or vehicle, or other suitable electronic equipment.
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 (e.g., glass, ceramic, plastic, sapphire, etc.). In other situations, housing 12 or at least some of the structures that make up housing 12 may be formed from metal elements.
Device 10 may, if desired, have a display such as display 6. Display 6 may be mounted on the front face of device 10. Display 6 may be a touch screen that incorporates capacitive touch electrodes or may be insensitive to touch. The rear face of housing 12 (i.e., the face of device 10 opposing the front face of device 10) may have a substantially planar housing wall such as rear housing wall 12R (e.g., a planar housing wall). Rear housing wall 12R may have slots that pass entirely through the rear housing wall and that therefore separate portions of housing 12 from each other. Rear housing wall 12R may include conductive portions and/or dielectric portions. If desired, rear housing wall 12R may include a planar metal layer covered by a thin layer or coating of dielectric such as glass, plastic, sapphire, or ceramic. Housing 12 may also have shallow grooves that do not pass entirely through housing 12. The slots and grooves may be filled with plastic or other dielectric. If desired, portions of housing 12 that have been separated from each other (e.g., by a through slot) may be joined by internal conductive structures (e.g., sheet metal or other metal members that bridge the slot).
Housing 12 may include peripheral housing structures such as peripheral structures 12W. Peripheral structures 12W and conductive portions of rear housing wall 12R may sometimes be referred to herein collectively as conductive structures of housing 12. Peripheral structures 12W may run around the periphery of device 10 and display 6. In configurations in which device 10 and display 6 have a rectangular shape with four edges, peripheral structures 12W may be implemented using peripheral housing structures that have a rectangular ring shape with four corresponding edges and that extend from rear housing wall 12R to the front face of device 10 (as an example). Peripheral structures 12W or part of peripheral structures 12W may serve as a bezel for display 6 (e.g., a cosmetic trim that surrounds all four sides of display 6 and/or that helps hold display 6 to device 10) if desired. Peripheral structures 12W may, if desired, form sidewall structures for device 10 (e.g., by forming a metal band with vertical sidewalls, curved sidewalls, etc.).
Peripheral structures 12W may be formed of a conductive material such as metal and may therefore sometimes be referred to as peripheral conductive housing structures, conductive housing structures, peripheral metal structures, peripheral conductive sidewalls, peripheral conductive sidewall structures, conductive housing sidewalls, peripheral conductive housing sidewalls, sidewalls, sidewall structures, or a peripheral conductive housing member (as examples). Peripheral conductive housing structures 12W may be formed from a metal such as stainless steel, aluminum, or other suitable materials. One, two, or more than two separate structures may be used in forming peripheral conductive housing structures 12W.
It is not necessary for peripheral conductive housing structures 12W to have a uniform cross-section. For example, the top portion of peripheral conductive housing structures 12W may, if desired, have an inwardly protruding lip that helps hold display 6 in place. The bottom portion of peripheral conductive housing structures 12W may also have an enlarged lip (e.g., in the plane of the rear surface of device 10). Peripheral conductive housing structures 12W may have substantially straight vertical sidewalls, may have sidewalls that are curved, or may have other suitable shapes. In some configurations (e.g., when peripheral conductive housing structures 12W serve as a bezel for display 6), peripheral conductive housing structures 12W may run around the lip of housing 12 (i.e., peripheral conductive housing structures 12W may cover only the edge of housing 12 that surrounds display 6 and not the rest of the sidewalls of housing 12).
Rear housing wall 12R may lie in a plane that is parallel to display 6. In configurations for device 10 in which some or all of rear housing wall 12R is formed from metal, it may be desirable to form parts of peripheral conductive housing structures 12W as integral portions of the housing structures forming rear housing wall 12R. For example, rear housing wall 12R of device 10 may include a planar metal structure and portions of peripheral conductive housing structures 12W on the sides of housing 12 may be formed as flat or curved vertically extending integral metal portions of the planar metal structure (e.g., housing structures 12R and 12W may be formed from a continuous piece of metal in a unibody configuration). Housing structures such as these may, if desired, be machined from a block of metal and/or may include multiple metal pieces that are assembled together to form housing 12. Rear housing wall 12R may have one or more, two or more, or three or more portions. Peripheral conductive housing structures 12W and/or conductive portions of rear housing wall 12R may form one or more exterior surfaces of device 10 (e.g., surfaces that are visible to a user of device 10) and/or may be implemented using internal structures that do not form exterior surfaces of device 10 (e.g., conductive housing structures that are not visible to a user of device 10 such as conductive structures that are covered with layers such as thin cosmetic layers, protective coatings, and/or other coating layers that may include dielectric materials such as glass, ceramic, plastic, or other structures that form the exterior surfaces of device 10 and/or serve to hide peripheral conductive structures 12W and/or conductive portions of rear housing wall 12R from view of the user).
Display 6 may have an array of pixels that form an active area AA that displays images for a user of device 10. For example, active area AA may include an array of display pixels. The array of pixels may be formed from liquid crystal display (LCD) components, an array of electrophoretic pixels, an array of plasma display pixels, an array of organic light-emitting diode display pixels or other light-emitting diode pixels, an array of electrowetting display pixels, or display pixels based on other display technologies. If desired, active area AA may include touch sensors such as touch sensor capacitive electrodes, force sensors, or other sensors for gathering a user input.
Display 6 may have an inactive border region that runs along one or more of the edges of active area AA. Inactive area IA may be free of pixels for displaying images and may overlap circuitry and other internal device structures in housing 12. To block these structures from view by a user of device 10, the underside of the display cover layer or other layers in display 6 that overlaps inactive area IA may be coated with an opaque masking layer in inactive area IA. The opaque masking layer may have any suitable color.
Display 6 may be protected using a display cover layer such as a layer of transparent glass, clear plastic, transparent ceramic, sapphire, or other transparent crystalline material, or other transparent layer(s). The display cover layer may have a planar shape, a convex curved profile, a shape with planar and curved portions, a layout that includes a planar main area surrounded on one or more edges with a portion that is bent out of the plane of the planar main area, or other suitable shapes. The display cover layer may cover the entire front face of device 10. In another suitable arrangement, the display cover layer may cover substantially all of the front face of device 10 or only a portion of the front face of device 10. Openings may be formed in the display cover layer. For example, an opening may be formed in the display cover layer to accommodate a button. An opening may also be formed in the display cover layer to accommodate ports such as speaker port 8 or a microphone port. Openings may be formed in housing 12 to form communications ports (e.g., an audio jack port, a digital data port, etc.) and/or audio ports for audio components such as a speaker and/or a microphone if desired.
Display 6 may include conductive structures such as an array of capacitive electrodes for a touch sensor, conductive lines for addressing pixels, driver circuits, etc. Housing 12 may include internal conductive structures such as metal frame members and a planar conductive housing member (sometimes referred to as a backplate) that spans the walls of housing 12 (i.e., a substantially rectangular sheet formed from one or more metal parts that is welded or otherwise connected between opposing sides of peripheral conductive structures 12W). The backplate may form an exterior rear surface of device 10 or may be covered by layers such as thin cosmetic layers, protective coatings, and/or other coatings that may include dielectric materials such as glass, ceramic, plastic, or other structures that form the exterior surfaces of device 10 and/or serve to hide the backplate from view of the user. Device 10 may also include conductive structures such as printed circuit boards, components mounted on printed circuit boards, and other internal conductive structures. These conductive structures, which may be used in forming a ground plane in device 10, may extend under active area AA of display 6, for example.
In regions 2 and 4, openings may be formed within the conductive structures of device 10 (e.g., between peripheral conductive housing structures 12W and opposing conductive ground structures such as conductive portions of rear housing wall 12R, conductive traces on a printed circuit board, conductive electrical components in display 6, etc.). These openings, which may sometimes be referred to as gaps, may be filled with air, plastic, and/or other dielectrics and may be used in forming slot antenna resonating elements for one or more antennas in device 10, if desired.
Conductive housing structures and other conductive structures in device 10 may serve as a ground plane for the antennas in device 10. The openings in regions 2 and 4 may serve as slots in open or closed slot antennas, may serve as a central dielectric region that is surrounded by a conductive path of materials in a loop antenna, may serve as a space that separates an antenna resonating element such as a strip antenna resonating element or an inverted-F antenna resonating element from the ground plane, may contribute to the performance of a parasitic antenna resonating element, or may otherwise serve as part of antenna structures formed in regions 2 and 4. If desired, the ground plane that is under active area AA of display 6 and/or other metal structures in device 10 may have portions that extend into parts of the ends of device 10 (e.g., the ground may extend towards the dielectric-filled openings in regions 2 and 4), thereby narrowing the slots in regions 2 and 4.
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 opposing first and second ends of an elongated device housing (e.g., ends at regions 2 and 4 of device 10 of
Portions of peripheral conductive housing structures 12W may be provided with peripheral gap structures. For example, peripheral conductive housing structures 12W may be provided with one or more gaps such as gaps 9, as shown in
If desired, openings in housing 12 such as grooves that extend partway or completely through housing 12 may extend across the width of the rear wall of housing 12 and may penetrate through the rear wall of housing 12 to divide the rear wall into different portions. These grooves may also extend into peripheral conductive housing structures 12W and may form antenna slots, gaps 9, and other structures in device 10. Polymer or other dielectric may fill these grooves and other housing openings. In some situations, housing openings that form antenna slots and other structure may be filled with a dielectric such as air.
In a typical scenario, device 10 may have one or more upper antennas and one or more lower antennas (as an example). An upper antenna may, for example, be formed at the upper end of device 10 in region 4. A lower antenna may, for example, be formed at the lower end of device 10 in region 2. The antennas may be used separately to cover identical communications bands, overlapping communications bands, or separate communications bands. The antennas may be used to implement an antenna diversity scheme or a multiple-input-multiple-output (MIMO) antenna scheme.
Antennas in device 10 may be used to support any communications bands of interest. For example, device 10 may include antenna structures for supporting local area network communications, voice and data cellular telephone communications, global positioning system (GPS) communications or other satellite navigation system communications, Bluetooth® communications, near-field communications, etc. Two or more antennas in device 10 may be arranged in a phased antenna array for covering millimeter and centimeter wave communications if desired.
In order to provide an end user of device 10 with as large of a display as possible (e.g., to maximize an area of the device used for displaying media, running applications, etc.), it may be desirable to increase the amount of area at the front face of device 10 that is covered by active area AA of display 6. Increasing the size of active area AA may reduce the size of inactive area IA within device 10. This may reduce the area behind display 6 that is available for antennas within device 10. For example, active area AA of display 6 may include conductive structures that serve to block radio-frequency signals handled by antennas mounted behind active area AA from radiating through the front face of device 10. It would therefore be desirable to be able to provide antennas that occupy a small amount of space within device 10 (e.g., to allow for as large of a display active area AA as possible) while still allowing the antennas to communicate with wireless equipment external to device 10 with satisfactory efficiency bandwidth.
Control circuitry 14 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, control circuitry 14 may be used in implementing communications protocols. Communications protocols that may be implemented using control circuitry 14 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 or other wireless personal area network protocols, IEEE 802.11ad protocols, cellular telephone protocols, MIMO protocols, antenna diversity protocols, satellite navigation system protocols, etc.
Device 10 may include input-output circuitry 16. Input-output circuitry 16 may include input-output devices 18. Input-output devices 18 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 may include user interface devices, data port devices, and other input-output components. For example, input-output devices may include touch screens, displays without touch sensor capabilities, buttons, joysticks, scrolling wheels, touch pads, key pads, keyboards, microphones, cameras, speakers, status indicators, light sources, audio jacks and other audio port components, digital data port devices, light sensors, accelerometers or other components that can detect motion and device orientation relative to the Earth, capacitance sensors, proximity sensors (e.g., a capacitive proximity sensor and/or an infrared proximity sensor), magnetic sensors, and other sensors and input-output components.
Input-output circuitry 16 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 40, 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 20 for handling various radio-frequency communications bands. For example, circuitry 34 may include transceiver circuitry 22, 24, 26, and 28.
Transceiver circuitry 24 may be wireless local area network transceiver circuitry. Transceiver circuitry 24 may handle 2.4 GHz and 5 GHz bands for Wi-Fi® (IEEE 802.11) communications or other wireless local area network (WLAN) bands and may handle the 2.4 GHz Bluetooth® communications band or other wireless personal area network (WPAN) bands.
Circuitry 34 may use cellular telephone transceiver circuitry 26 for handling wireless communications in frequency ranges such as a low communications band from 600 to 960 MHz, a midband from 1710 to 2170 MHz, a high band from 2300 to 2700 MHz, an ultra-high band from 3400 to 3700 MHz, or other communications bands between 600 MHz and 4000 MHz or other suitable frequencies (as examples). Circuitry 26 may handle voice data and non-voice data.
Millimeter wave transceiver circuitry 28 (sometimes referred to as extremely high frequency (EHF) transceiver circuitry 28 or transceiver circuitry 28) may support communications at frequencies between about 10 GHz and 300 GHz. For example, transceiver circuitry 28 may support communications in Extremely High Frequency (EHF) or millimeter wave communications bands between about 30 GHz and 300 GHz and/or in centimeter wave communications bands between about 10 GHz and 30 GHz (sometimes referred to as Super High Frequency (SHF) bands). As examples, transceiver circuitry 28 may support communications in an IEEE K communications band between about 18 GHz and 27 GHz, a Ka communications band between about 26.5 GHz and 40 GHz, a Ku communications band between about 12 GHz and 18 GHz, a V communications band between about 40 GHz and 75 GHz, a W communications band between about 75 GHz and 110 GHz, or any other desired frequency band between approximately 10 GHz and 300 GHz. If desired, circuitry 28 may support IEEE 802.11ad communications at 60 GHz and/or 5th generation mobile networks or 5th generation wireless systems (5G) communications bands between 27 GHz and 90 GHz. If desired, circuitry 28 may support communications at multiple frequency bands between 10 GHz and 300 GHz such as a first band from 27.5 GHz to 28.5 GHz, a second band from 37 GHz to 41 GHz, and a third band from 57 GHz to 71 GHz, or other communications bands between 10 GHz and 300 GHz. Circuitry 28 may be formed from one or more integrated circuits (e.g., multiple integrated circuits mounted on a common printed circuit in a system-in-package device, one or more integrated circuits mounted on different substrates, etc.). While circuitry 28 is sometimes referred to herein as millimeter wave transceiver circuitry 28, millimeter wave transceiver circuitry 28 may handle communications at any desired communications bands at frequencies between 10 GHz and 300 GHz (e.g., transceiver circuitry 28 may transmit and receive radio-frequency signals in millimeter wave communications bands, centimeter wave communications bands, etc.).
Wireless communications circuitry 34 may include satellite navigation system circuitry such as Global Positioning System (GPS) receiver circuitry 22 for receiving GPS signals at 1575 MHz or for handling other satellite positioning data (e.g., GLONASS signals at 1609 MHz). Satellite navigation system signals for receiver 22 are received from a constellation of satellites orbiting the earth.
In satellite navigation system links, cellular telephone links, and other long-range links, wireless signals are typically used to convey data over thousands of feet or miles. In Wi-Fi® and Bluetooth® links at 2.4 and 5 GHz and other short-range wireless links, wireless signals are typically used to convey data over tens or hundreds of feet. Extremely high frequency (EHF) wireless transceiver circuitry 28 may convey signals that travel (over short distances) between a transmitter and a receiver over a line-of-sight path. To enhance signal reception for millimeter and centimeter wave communications, phased antenna arrays and beam steering techniques may be used (e.g., schemes in which antenna signal phase and/or magnitude for each antenna in an array is adjusted to perform beam steering). Antenna diversity schemes may also be used to ensure that the antennas that have become blocked or that are otherwise degraded due to the operating environment of device 10 can be switched out of use and higher-performing antennas used in their place.
Wireless communications circuitry 34 can include circuitry for other short-range and long-range wireless links if desired. For example, wireless communications circuitry 34 may include circuitry for receiving television and radio signals, paging system transceivers, near field communications (NFC) circuitry, etc.
Antennas 40 in wireless communications circuitry 34 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, stacked patch antenna structures, antenna structures having parasitic elements, inverted-F antenna structures, slot antenna structures, planar inverted-F antenna structures, monopoles, dipoles, helical antenna structures, Yagi (Yagi-Uda) antenna structures, surface integrated waveguide structures, hybrids of these designs, etc. If desired, one or more of antennas 40 may be cavity-backed antennas. Different types of antennas may be used for different bands and combinations of bands. For example, one type of antenna may be used in forming a local wireless link antenna and another type of antenna may be used in forming a remote wireless link antenna. Dedicated antennas may be used for receiving satellite navigation system signals or, if desired, antennas 40 can be configured to receive both satellite navigation system signals and signals for other communications bands (e.g., wireless local area network signals and/or cellular telephone signals). Antennas 40 can be arranged in phased antenna arrays for handling millimeter wave and centimeter wave communications.
Transmission line paths may be used to route antenna signals within device 10. For example, transmission line paths may be used to couple antennas 40 to transceiver circuitry 20. Transmission line paths in device 10 may include coaxial cable paths, microstrip transmission lines, stripline transmission lines, edge-coupled microstrip transmission lines, edge-coupled stripline transmission lines, waveguide structures for conveying signals at millimeter wave frequencies (e.g., coplanar waveguides or grounded coplanar waveguides), transmission lines formed from combinations of transmission lines of these types, etc.
Transmission line paths in device 10 may be integrated into rigid and/or flexible printed circuit boards if desired. In one suitable arrangement, transmission line paths in device 10 may include transmission line conductors (e.g., signal and/or ground conductors) that are integrated within multilayer laminated structures (e.g., layers of a conductive material such as copper and a dielectric material such as a resin that are laminated together without intervening adhesive) that may be folded or bent in multiple dimensions (e.g., two or three dimensions) and that maintain a bent or folded shape after bending (e.g., the multilayer laminated structures may be folded into a particular three-dimensional shape to route around other device components and may be rigid enough to hold its shape after folding without being held in place by stiffeners or other structures). All of the multiple layers of the laminated structures may be batch laminated together (e.g., in a single pressing process) without adhesive (e.g., as opposed to performing multiple pressing processes to laminate multiple layers together with adhesive). Filter circuitry, switching circuitry, impedance matching circuitry, and other circuitry may be interposed within the transmission lines, if desired.
Device 10 may contain multiple antennas 40. The antennas may be used together or one of the antennas may be switched into use while other antenna(s) are switched out of use. If desired, control circuitry 14 may be used to select an optimum antenna to use in device 10 in real time and/or to select an optimum setting for adjustable wireless circuitry associated with one or more of antennas 40. Antenna adjustments may be made to tune antennas to perform in desired frequency ranges, to perform beam steering with a phased antenna array, and to otherwise optimize antenna performance. Sensors may be incorporated into antennas 40 to gather sensor data in real time that is used in adjusting antennas 40 if desired.
In some configurations, antennas 40 may include antenna arrays (e.g., phased antenna arrays to implement beam steering functions). For example, the antennas that are used in handling millimeter wave signals for extremely high frequency wireless transceiver circuits 28 may be implemented as phased antenna arrays. The radiating elements in a phased antenna array for supporting millimeter wave communications may be patch antennas, dipole antennas, Yagi (Yagi-Uda) antennas, or other suitable antenna elements. Transceiver circuitry 28 can be integrated with the phased antenna arrays to form integrated phased antenna array and transceiver circuit modules or packages (sometimes referred to herein as integrated antenna modules or antenna modules) if desired.
In devices such as handheld devices, the presence of an external object such as the hand of a user or a table or other surface on which a device is resting has a potential to block wireless signals such as millimeter wave signals. In addition, millimeter wave communications typically require a line of sight between antennas 40 and the antennas on an external device. Accordingly, it may be desirable to incorporate multiple phased antenna arrays into device 10, each of which is placed in a different location within or on device 10. With this type of arrangement, an unblocked phased antenna array may be switched into use and, once switched into use, the phased antenna array may use beam steering to optimize wireless performance. Similarly, if a phased antenna array does not face or have a line of sight to an external device, another phased antenna array that has line of sight to the external device may be switched into use and that phased antenna array may use beam steering to optimize wireless performance. Configurations in which antennas from one or more different locations in device 10 are operated together may also be used (e.g., to form a phased antenna array, etc.).
Antennas 40 in phased antenna array 60 may be arranged in any desired number of rows and columns or in any other desired pattern (e.g., the antennas need not be arranged in a grid pattern having rows and columns). During signal transmission operations, transmission line paths 64 may be used to supply signals (e.g., radio-frequency signals such as millimeter wave and/or centimeter wave signals) from transceiver circuitry 28 (
The use of multiple antennas 40 in phased antenna array 60 allows beam steering arrangements to be implemented by controlling the relative phases and magnitudes (amplitudes) of the radio-frequency signals conveyed by the antennas. In the example of
Phase and magnitude controllers 62 may each include circuitry for adjusting the phase of the radio-frequency signals on transmission line paths 64 (e.g., phase shifter circuits) and/or circuitry for adjusting the magnitude of the radio-frequency signals on transmission line paths 64 (e.g., power amplifier and/or low noise amplifier circuits). Phase and magnitude controllers 62 may sometimes be referred to collectively herein as beam steering circuitry (e.g., beam steering circuitry that steers the beam of radio-frequency signals transmitted and/or received by phased antenna array 60).
Phase and magnitude controllers 62 may adjust the relative phases and/or magnitudes of the transmitted signals that are provided to each of the antennas in phased antenna array 60 and may adjust the relative phases and/or magnitudes of the received signals that are received by phased antenna array 60 from external equipment. Phase and magnitude controllers 62 may, if desired, include phase detection circuitry for detecting the phases of the received signals that are received by phased antenna array 60 from external equipment. The term “beam” or “signal beam” may be used herein to collectively refer to wireless signals that are transmitted and received by phased antenna array 60 in a particular direction. The term “transmit beam” may sometimes be used herein to refer to wireless radio-frequency signals that are transmitted in a particular direction whereas the term “receive beam” may sometimes be used herein to refer to wireless radio-frequency signals that are received from a particular direction.
If, for example, phase and magnitude controllers 62 are adjusted to produce a first set of phases and/or magnitudes for transmitted millimeter wave signals, the transmitted signals will form a millimeter wave frequency transmit beam as shown by beam 66 of
Each phase and magnitude controller 62 may be controlled to produce a desired phase and/or magnitude based on a corresponding control signal 58 received from control circuitry 14 of
When performing millimeter or centimeter wave communications, radio-frequency signals are conveyed over a line of sight path between phased antenna array 60 and external equipment. If the external equipment is located at location A of
A schematic diagram of an antenna 40 that may be formed in phased antenna array 60 (e.g., as antenna 40-1, 40-2, 40-3, and/or 40-N in phased antenna array 60 of
Any desired antenna structures may be used for implementing antenna 40. In one suitable arrangement that is sometimes described herein as an example, patch antenna structures may be used for implementing antenna 40. Antennas 40 that are implemented using patch antenna structures may sometimes be referred to herein as patch antennas. An illustrative patch antenna that may be used in phased antenna array 60 of
As shown in
The length of the sides of patch element 104 may be selected so that antenna 40 resonates at a desired operating frequency. For example, the sides of patch element 104 may each have a length 114 that is approximately equal to half of the wavelength of the signals conveyed by antenna 40 (e.g., the effective wavelength given the dielectric properties of the materials surrounding patch element 104). In one suitable arrangement, length 114 may be between 0.8 mm and 1.2 mm (e.g., approximately 1.1 mm) for covering a millimeter wave frequency band between 57 GHz and 70 GHz or between 1.6 mm and 2.2 mm (e.g., approximately 1.85 mm) for covering a millimeter wave frequency band between 37 GHz and 41 GHz, as just two examples.
The example of
To enhance the polarizations handled by antenna 40, antenna 40 may be provided with multiple feeds. As shown in
Holes or openings such as openings 117 and 119 may be formed in ground plane 102. Transmission line path 64V may include a vertical conductor (e.g., a conductive through-via, conductive pin, metal pillar, solder bump, combinations of these, or other vertical conductive interconnect structures) that extends through hole 117 to positive antenna feed terminal 98-1 on patch element 104. Transmission line path 64H may include a vertical conductor that extends through hole 119 to positive antenna feed terminal 98-2 on patch element 104. This example is merely illustrative and, if desired, other transmission line structures may be used (e.g., coaxial cable structures, stripline transmission line structures, etc.).
When using the first antenna feed associated with port P1, antenna 40 may transmit and/or receive radio-frequency signals having a first polarization (e.g., the electric field E1 of antenna signals 115 associated with port P1 may be oriented parallel to the Y-axis in
One of ports P1 and P2 may be used at a given time so that antenna 40 operates as a single-polarization antenna or both ports may be operated at the same time so that antenna 40 operates with other polarizations (e.g., as a dual-polarization antenna, a circularly-polarized antenna, an elliptically-polarized antenna, etc.). If desired, the active port may be changed over time so that antenna 40 can switch between covering vertical or horizontal polarizations at a given time. Ports P1 and P2 may be coupled to different phase and magnitude controllers 62 (
If care is not taken, antennas 40 such as dual-polarization patch antennas of the type shown in
As shown in
At least some or an entirety of parasitic element 106 may overlap patch element 104. In the example of
If desired, antenna 40 of
When configured in this way, antenna 40 may cover a relatively wide millimeter wave communications band of interest such as a frequency band between 57 GHz and 71 GHz. The example of
As shown in
In the example of
Conductive structures such as peripheral conductive housing structures 12W may block electromagnetic energy conveyed by phased antenna arrays in device 10 such as phased antenna array 60 of
When mounted behind dielectric cover layer 120, phased antenna array 60 may transmit and receive wireless signals (e.g., wireless signals at millimeter and centimeter wave frequencies) such as radio-frequency signals 124 through dielectric cover layer 120. When mounted behind dielectric cover layer 122, phased antenna array 60 may transmit and receive wireless signals such as radio-frequency signals 126 through dielectric cover layer 120.
In practice, radio-frequency signals at millimeter and centimeter wave frequencies such as radio-frequency signals 124 and 126 may be subject to substantial attenuation, particularly through relatively dense mediums such as dielectric cover layers 120 and 122. The radio-frequency signals may also be subject to destructive interference due to reflections within dielectric cover layers 120 and 122 and may generate undesirable surface waves at the interfaces between dielectric cover layers 120 and 122 and the interior of device 10. For example, radio-frequency signals conveyed by a phased antenna array 60 mounted behind dielectric cover layer 120 may generate surface waves at the interior surface of dielectric cover layer 120. If care is not taken, the surface waves may propagate laterally outward (e.g., along the interior surface of dielectric cover layer 120) and may escape out the sides of device 10, as shown by arrows 125. Surface waves such as these may reduce the overall antenna efficiency for the phased antenna array, may generate undesirable interference with external equipment, and may subject the user to undesirable radio-frequency energy absorption, for example. Similar surface waves can also be generated at the interior surface of dielectric cover layer 122.
Substrate 140 may be, for example, a rigid or flexible printed circuit board or other dielectric substrate. Substrate 140 may include multiple stacked dielectric layers 142 (e.g., multiple layers of printed circuit board substrate such as multiple layers of fiberglass-filled epoxy) or may include a single dielectric layer. Substrate 140 may include any desired dielectric materials such as epoxy, plastic, ceramic, glass, foam, or other materials. Antennas 40 in phased array antenna 60 may be mounted at a surface of substrate 140 or may be partially or completely embedded within substrate 140 (e.g., within a single layer of substrate 140 or within multiple layers of substrate 140).
In the example of
Surface 150 of substrate 140 may be mounted against (e.g., attached to) interior surface 146 of dielectric cover layer 130. For example, substrate 140 may be mounted to dielectric cover layer 130 using an adhesive layer such as adhesive layer 136. This is merely illustrative. If desired, substrate 140 may be affixed to dielectric cover layer 130 using other adhesives, screws, pins, springs, conductive housing structures, etc. Substrate 140 need not be affixed to dielectric cover layer 130 if desired (e.g., substrate 140 may be in direct contact with dielectric cover layer 130 without being affixed to dielectric cover layer 130). Parasitic elements 106 in phased antenna array 60 may be in direct contact with interior surface 146 of dielectric cover layer 130 (e.g., in scenarios where adhesive layer 136 is omitted or where adhesive layer 136 has openings that align with parasitic elements 106) or may be coupled to interior surface 146 by adhesive layer 136 (e.g., parasitic elements 106 may be in direct contact with adhesive layer 136).
Phased array antenna 60 and substrate 140 may sometimes be referred to herein collectively as antenna module 138. If desired, transceiver circuitry 134 (e.g., transceiver circuitry 28 of
If desired, a conductive layer (e.g., a conductive portion of rear housing wall 12R when dielectric cover layer 130 forms dielectric cover layer 122 of
Conductive traces 154 may sometimes be referred to herein as ground traces 154, ground plane 154, antenna ground 154, or ground plane traces 154. The layers 142 in substrate 140 between ground traces 154 and dielectric cover layer 130 may sometimes be referred to herein as antenna layers 142. The layers in substrate 140 between ground traces 154 and surface 152 of substrate 140 may sometimes be referred to herein as transmission line layers. The antenna layers may be used to support patch elements 104 and parasitic elements 106 of the antennas 40 in phased antenna array 60. The transmission line layers may be used to support transmission line paths (e.g., transmission line paths 64V and 64H of
Transceiver circuitry 134 may include transceiver ports 160. Each transceiver port 160 may be coupled to a respective antenna 40 over one or more corresponding transmission line paths 64 (e.g., transmission line paths such as transmission line paths 64H and 64V of
Transmission line paths for antennas 40 may be embedded within the transmission line layers of substrate 140. The transmission line paths may include conductive traces 168 within the transmission line layers of substrate 140 (e.g., conductive traces on one or more dielectric layers 142 within substrate 140). Conductive traces 168 may form signal conductor 94 and/or ground conductor 90 (
Conductive traces 168 may be coupled to the positive antenna feed terminals of antennas 40 (e.g., positive antenna feed terminals 98-1 and 98-2 of
If care is not taken, radio-frequency signals transmitted by antennas 40 in phased antenna array 60 may reflect off of interior surface 146, thereby limiting the gain of phased antenna array 60 in some directions. Mounting conductive structures from antennas 40 (e.g., patch elements 104 or parasitic elements 106) directly against interior surface 146 (e.g., either through adhesive layer 136 or in direct contact with interior surface 146) may serve to minimize these reflections, thereby optimizing antenna gain for phased antenna array 60 in all directions. Adhesive layer 136 may have a selected thickness 176 that is sufficiently small so as to minimize these reflections while still allowing for a satisfactory adhesion between dielectric cover layer 130 and substrate 140. As an example, thickness 176 may be between 300 microns and 400 microns, between 200 microns and 500 microns, between 325 microns and 375 microns, between 100 microns and 600 microns, etc.
In practice, the radio-frequency signals transmitted by phased antenna array 60 may reflect within dielectric cover layer 130 (e.g., at interior surface 146 and/or exterior surface 148 of dielectric cover layer 130). Such reflections may, for example, be due to the difference in dielectric constant between dielectric cover layer 130 and the space external to device 10 as well as the difference in dielectric constant between substrate 140 and dielectric cover layer 130. If care is not taken, the reflected signals may destructively interfere with each other and/or with the transmitted signals within dielectric cover layer 130. This may lead to a deterioration in antenna gain for phased antenna array 60 over some angles, for example.
In order to mitigate these destructive interference effects, the dielectric constant DK1 of dielectric cover layer 130 and thickness 144 of dielectric cover layer 130 may be selected so that dielectric cover layer 130 forms a quarter wave impedance transformer for phased antenna array 60. When configured in this way, dielectric cover layer 130 may optimize matching of the antenna impedance for phased antenna array 60 to the free space impedance external to device 10 and may mitigate destructive interference within dielectric cover layer 130.
As examples, dielectric cover layer 130 may be formed of a material having a dielectric constant between about 3.0 and 10.0 (e.g., between 4.0 and 9.0, between 5.0 and 8.0, between 5.5 and 7.0, between 5.0 and 7.0, etc.). In one particular arrangement, dielectric cover layer 130 may be formed from glass, ceramic, or other dielectric materials having a dielectric constant of about 6.0. Thickness 144 of dielectric cover layer 130 may be selected to be between 0.15 and 0.25 times the effective wavelength of operation of phased antenna array 60 in the material used to form dielectric cover layer 130 (e.g., approximately one-quarter of the effective wavelength). The effective wavelength is given by dividing the free space wavelength of operation of phased antenna array 60 (e.g., a centimeter or millimeter wavelength corresponding to a frequency between 10 GHz and 300 GHz) by a constant factor (e.g., the square root of the dielectric constant of the material used to form dielectric cover layer 130). This example is merely illustrative and, if desired, thickness 144 may be selected to be between 0.17 and 0.23 times the effective wavelength, between 0.12 and 0.28 times the effective wavelength, between 0.19 and 0.21 times the effective wavelength, between 0.15 and 0.30 times the effective wavelength, etc. In practice, thickness 144 may be between 0.8 mm and 1.0 mm, between 0.85 mm and 0.95 mm, or between 0.7 mm and 1.1 mm, as examples. Adhesive layer 136 may be formed from dielectric materials having a dielectric constant that is less than dielectric constant DK1 of dielectric cover layer 130.
Each antenna 40 may be separated from the other antennas 40 in phased antenna array 60 by vertical conductive structures such as conductive through vias 170 (sometimes referred to herein as conductive vias 170). Sets or fences of conductive vias 170 may laterally surround each antenna 40 in phased antenna array 60. Conductive vias 170 may extend through substrate 140 from surface 150 to ground traces 156. Conductive landing pads (not shown in
As shown in
The conductive cavity formed from ground traces 154 and conductive vias 170 may serve to enhance the gain of each antenna 40 in phased antenna array 60 (e.g., helping to compensate for attenuation and destructive interference associated with the presence of dielectric cover layer 130). Conductive vias 170 may also serve to isolate the antennas 40 in phased antenna array 60 from each other if desired (e.g., to minimize electromagnetic cross-coupling between the antennas).
Each antenna 40 in phased antenna array 60, its corresponding conductive vias 170, its corresponding volume 172, and its corresponding portion of ground traces 154 may sometimes be referred to herein as an antenna unit cell 174. Antenna unit cells 174 in phased antenna array 60 may be arranged in any desired pattern (e.g., a pattern having rows and/or columns or other shapes). Some conductive vias 170 may be shared by adjacent antenna unit cells 174 if desired.
Each antenna 40 in phased antenna array 60 may generate surface waves at interior surface 146 of dielectric cover layer 130 (e.g., surface waves such as surface waves 125 of
Load 184 associated with dielectric cover layer 130 of
Configuring dielectric cover layer 130 to form a quarter wave impedance transformer may allow antenna load 182 (antenna 40 of
As shown in
The fences of conductive vias 170 for each antenna unit cell 174 may be opaque at frequencies covered by antennas 40. Each conductive via 170 may be separated from two adjacent conductive vias 170 by a distance (pitch) 200. In order to be opaque at the frequencies covered by antennas 40, distance 200 may be less than about ⅛ of the wavelength of operation of antennas 40 (e.g., an effective wavelength after compensating for the dielectric effects of substrate 140 of
Each antenna 40 in phased antenna array 60 may be separated from one or more adjacent antennas 40 in phased antenna array 60 by distance 206. Distance 206 may be, for example, approximately equal to one-half of the wavelength of operation of antennas 40 (e.g., an effective wavelength given the dielectric properties of substrate 140 of
The example of
As shown in
As shown in
Antenna unit cells of different shapes and sizes such as the hexagonal antenna unit cells 174 of
If desired, the same phased antenna array 60 may include antennas 40 and/or antenna unit cells 174 of different shapes and sizes for concurrently covering different frequencies.
As shown in
Antennas 40H may be surrounded by respective sets (fences) of conductive vias 170 to form antenna unit cells 174H. Antennas 40L may be surrounded by respective sets (fences) of conductive vias 170 to form antenna unit cells 174L. Antenna unit cells 174L may be larger than antenna unit cells 174H (e.g., to accommodate the longer wavelengths associated with antennas 40L). In the example of
In the example of
The fences of conductive vias 170 in antenna unit cells 174L and 174H may have any desired shapes. In general, the fences of conductive vias may have shapes that are selected to allow antenna unit cells 174L and 174H to be placed (tiled) at predetermined locations without overlapping. The predetermined locations for the antenna unit cells may be selected so that the radiation pattern exhibited by phased antenna array 60 has a desired shape, so that surface waves generated by each antenna 40 are suitably canceled out at the periphery of dielectric cover layer 130 (
In another suitable arrangement, one or more antenna unit cells 174 in phased antenna array 60 may be provided with multiple antennas 40.
As shown in
The example of
When dielectric cover layer 130 is configured to form a quarter wave impedance transformer and fences of conductive vias are used to form antenna unit cells 174 (
The example of
The foregoing is merely illustrative and various modifications can be made to the described embodiments. The foregoing embodiments may be implemented individually or in any combination.
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