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. In addition, antennas that support millimeter wave and centimeter wave communications are often particularly susceptible to electromagnetic interference from nearby electronic components.
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 antennas and transceiver circuitry such as millimeter wave transceiver circuitry. The antennas may be arranged in a phased antenna array.
The phased antenna array may be mounted to a conductive rear wall of a conductive cavity in the electronic device. The conductive rear wall may have a rectangular periphery. The conductive cavity may include first, second, third, and fourth sidewalls extending from the conductive rear wall. A dielectric layer may cover the conductive cavity. The phased antenna array may transmit radio-frequency signals at a frequency between 10 GHz and 300 GHz through the dielectric layer.
The phased antenna array may include multiple patch antennas arranged in a single row or in a two-dimensional rectangular pattern. Each patch antenna may include a rectangular (e.g., square) patch element. Each patch element may have first and second perpendicular edges. The first edges of all of the patch elements in the phased antenna array may be aligned with a first axis. The second edges of all of the patch elements in the phased antenna array may be aligned with a second axis perpendicular to the first axis. The first and second axes may extend at non-parallel angles with respect to each of the first, second, third, and fourth sidewalls of the conductive cavity. For example, the first and second axes may each be oriented at 45 degrees with respect to each of the first, second, third, and fourth sidewalls of the conductive cavity.
Each patch element in the phased antenna array may be fed using first and second positive antenna feed terminals. The first positive antenna feed terminal may be coupled to the patch element along the first edge. The second positive antenna feed terminal may be coupled to the patch element along the second edge. The first and second positive antenna feed terminals may cover orthogonal linear polarizations. When arranged in this way, the center of each patch element may be located at a given distance from both the first and second sidewalls of the conductive cavity. The first and second positive antenna feed terminals of each patch element may be located at a first distance from the first sidewall and a second distance from the second sidewall.
The conductive cavity may prevent electromagnetic interference with the phased antenna array while symmetrically loading the impedance of both the first and second positive antenna feed terminals in each patch element. This may allow the phased antenna array to operate with optimal antenna efficiency using both polarizations despite being mounted within a rectangular conductive cavity.
An electronic device such as electronic device 10 of
Electronic device 10 may be a computing device such as a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wristwatch device, a pendant device, a headphone or earpiece device, a virtual or augmented reality headset device, a device embedded in eyeglasses or other equipment worn on a user's head, or other wearable or miniature device, a television, a computer display that does not contain an embedded computer, a gaming device, a navigation device, an embedded system such as a system in which electronic equipment with a display is mounted in a kiosk or automobile, a wireless access point or base station, a desktop computer, a keyboard, a gaming controller, a computer mouse, a mousepad, a trackpad or touchpad, equipment that implements the functionality of two or more of these devices, or other electronic equipment. In the illustrative configuration of
As shown in
Display 8 may be a touch screen display that incorporates a layer of conductive capacitive touch sensor electrodes or other touch sensor components (e.g., resistive touch sensor components, acoustic touch sensor components, force-based touch sensor components, light-based touch sensor components, etc.) or may be a display that is not touch-sensitive. Capacitive touch screen electrodes may be formed from an array of indium tin oxide pads or other transparent conductive structures.
Display 8 may include an array of display pixels formed from liquid crystal display (LCD) components, an array of electrophoretic display pixels, an array of plasma display pixels, an array of organic light-emitting diode display pixels, an array of electrowetting display pixels, or display pixels based on other display technologies.
Display 8 may be protected using a display cover layer such as a layer of transparent glass, clear plastic, sapphire, or other transparent dielectric. Openings may be formed in the display cover layer. For example, openings may be formed in the display cover layer to accommodate one or more buttons, sensor circuitry such as a fingerprint sensor or light sensor, ports such as a speaker port or microphone port, etc. Openings may be formed in housing 12 to form communications ports (e.g., an audio jack port, a digital data port, charging port, etc.). Openings in housing 12 may also be formed for audio components such as a speaker and/or a microphone.
Antennas may be mounted in housing 12. If desired, some of the antennas (e.g., antenna arrays that may implement beam steering, etc.) may be mounted under an inactive border region of display 8 (see, e.g., illustrative antenna locations 6 of
To avoid disrupting communications when an external object such as a human hand or other body part of a user blocks one or more antennas, antennas may be mounted at multiple locations in housing 12. Sensor data such as proximity sensor data, real-time antenna impedance measurements, signal quality measurements such as received signal strength information, and other data may be used in determining when one or more antennas is being adversely affected due to the orientation of housing 12, blockage by a user's hand or other external object, or other environmental factors. Device 10 can then switch one or more replacement antennas into use in place of the antennas that are being adversely affected.
Antennas may be mounted at the corners of housing 12 (e.g., in corner locations 6 of
A schematic diagram showing illustrative components that may be used in device 10 is shown in
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 WPAN 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 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 (WLAN) transceiver circuitry. Transceiver circuitry 24 may handle 2.4 GHz and 5 GHz bands for WiFi® (IEEE 802.11) communications and may handle the 2.4 GHz Bluetooth® communications band.
Circuitry 34 may use cellular telephone transceiver circuitry 26 for handling wireless communications in frequency ranges such as a communications band from 700 to 960 MHz, a communications band from 1710 to 2170 MHz, and a communications band from 2300 to 2700 MHz or other communications bands between 700 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 29.5 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., 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 WiFi® 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 over short distances that travel between transmitter and 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 stacked patch antenna structures, loop antenna structures, patch antenna structures, inverted-F antenna structures, slot antenna structures, planar inverted-F antenna structures, monopoles, dipoles, helical antenna structures, Yagi (Yagi-Uda) antenna 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 one or more antennas such as antennas arranged in one or more phased antenna arrays for handling millimeter 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 antenna structures 40 to transceiver circuitry 20. Transmission lines in device 10 may include coaxial probes realized by metalized vias, microstrip transmission lines, stripline transmission lines, edge-coupled microstrip transmission lines, edge-coupled stripline transmission lines, waveguide structures, transmission lines formed from combinations of transmission lines of these types, etc. Transmission lines in device 10 may be integrated into rigid and/or flexible printed circuit boards. In one suitable arrangement, transmission lines in device 10 may also include transmission line conductors (e.g., signal and ground conductors) 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.
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. Accordingly, it may be desirable to incorporate multiple antennas or phased antenna arrays into device 10, each of which is placed in a different location within device 10. With this type of arrangement, an unblocked antenna or phased antenna array may be switched into use. In scenarios where a phased antenna array is formed in device 10, once switched into use, the 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.
In configurations in which housing 12 is formed entirely or nearly entirely from a dielectric, antennas 40 may transmit and receive antenna signals through any suitable portion of the dielectric. In configurations in which housing 12 is formed from a conductive material such as metal, regions of the housing such as slots or other openings in the metal may be filled with plastic or other dielectric. Antennas 40 may be mounted in alignment with the dielectric in the openings. These openings, which may sometimes be referred to as dielectric antenna windows, dielectric gaps, dielectric-filled openings, dielectric-filled slots, elongated dielectric opening regions, etc., may allow antenna signals to be transmitted to external equipment from antennas 40 mounted within the interior of device 10 and may allow internal antennas 40 to receive antenna signals from external equipment. In another suitable arrangement, antennas 40 may be mounted on the exterior of conductive portions of housing 12.
In devices with phased antenna arrays, circuitry 34 may include gain and phase adjustment circuitry that is used in adjusting the signals associated with each antenna 40 in an array (e.g., to perform beam steering). Switching circuitry may be used to switch desired antennas 40 into and out of use. If desired, each of locations 50 may include multiple antennas 40 (e.g., a set of three antennas or more than three or fewer than three antennas in a phased antenna array) and, if desired, one or more antennas from one of locations 50 may be used in transmitting and receiving signals while using one or more antennas from another of locations 50 in transmitting and receiving signals.
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, as just one example.
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 120V (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 98V on patch element 104. Transmission line path 64H may include a vertical conductor 120H that extends through hole 119 to positive antenna feed terminal 98H 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 linear 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
Phased antenna array 60 may include any desired number of antennas 40 arranged in any desired number of rows and columns. In the example of
The antennas 40 in phased antenna array 60 may be formed on a dielectric substrate such as substrate 124. Substrate 124 may be, for example, a rigid or flexible printed circuit board or other dielectric substrate. Substrate 124 may include any desired dielectric materials such as epoxy, plastic, ceramic, glass, foam, or other materials. Substrate 124 may include multiple stacked dielectric layers (e.g., multiple layers of ceramic or multiple layers of printed circuit board substrate such as multiple layers of fiberglass-filled epoxy) or may include a single dielectric layer. Antennas 40 in phased antenna array 60 may be mounted at a surface of substrate 124 or may be partially or completely embedded within substrate 124 (e.g., within a single layer of substrate 124 or within multiple layers of substrate 124).
Ground plane 102 may include conductive traces embedded within substrate 124. Ground plane 102 may divide substrate 124 into transmission line layers 126B and antenna layers 126A. Transmission line layers 126B may include conductive traces used in forming transmission line paths 64 (
As shown in
Each antenna 40 in phased antenna array 60 may be laterally separated (e.g., in the X-Y plane of
During operation, electronic components adjacent to phased antenna array 60 (e.g., display 8 of
In order to mitigate these effects, phased antenna array 60 may be mounted within a conductive shielding cavity such as conductive cavity 132. Conductive cavity 132 may sometimes be referred to herein as conductive shielding can 132, conductive shielding pocket 132, or conductive shielding bucket 132. Conductive cavity 132 may be mounted to dielectric layer 122. For example, conductive cavity 132 may be coupled to dielectric layer 122 using adhesive or may be held against dielectric layer 122 by biasing structures. In another suitable arrangement, conductive cavity 132 may be spaced apart from dielectric layer 122.
As shown in
Phased antenna array 60 (dielectric substrate 124) may be mounted to conductive rear wall 138 of conductive cavity 132. If desired, ground plane 102 may be shorted to conductive cavity 132 so that conductive cavity 132 serves as a part of the antenna ground for phased antenna array 60. In another suitable arrangement, ground plane 102 within dielectric substrate 124 may be omitted and conductive cavity 132 may be held at a ground potential to serve as the antenna ground for phased antenna array 60. Holes or openings may be formed in conductive cavity 132 to allow transmission line structures (e.g., transmission line paths 64 of
Dielectric layer 122 may be separated from phased antenna array 60 in conductive cavity 132 by a gap such as gap 128 (sometimes referred to herein as cavity 128, dielectric cavity 128, or volume 128). Cavity 128 may be filled with a dielectric material such as plastic, foam, air, etc. Cavity 128 may have a height 130 (e.g., a height defined by the vertical distance between dielectric layer 122 and patch elements 104). Height 130 may be, for example, between 1 mm and 3 mm, between 1.5 mm and 2.5 mm, approximately 2 mm, less than 1 mm, or greater than 3 mm. The dielectric properties of cavity 128 and dielectric layer 122 may be selected to impedance match phased antenna array 60 to the exterior of device 10. Dielectric layer 122 may have a uniform thickness or may have a varying thickness across its lateral area. Phased antenna array 60 may transmit and receive radio-frequency signals 142 (e.g., at millimeter and centimeter wave frequencies) through dielectric layer 122.
Conductive sidewalls including sidewalls 136 and 134 may extend around all of the lateral sides of cavity 128 (e.g., to surround the lateral periphery of phased antenna array 60 and substrate 124). In this way, conductive cavity 132 and dielectric layer 122 may completely enclose or encapsulate phased antenna array 60 within cavity 128 (e.g., the edges of cavity 128 may be defined by conductive cavity 132 and dielectric layer 122).
Conductive cavity 132 may serve to block electromagnetic signals transmitted by phased antenna array 60 from escaping cavity 128 towards the interior of device 10. Similarly, conductive cavity 132 may serve to block electromagnetic interference at phased antenna array due to the presence of other electronic components in the vicinity of phased antenna array 60. Conductive cavity 132 may also serve to block surface waves generated at the interior surface of dielectric layer 122 within cavity 128 from propagating beyond cavity 128. In this way, phased antenna array 60 may be mounted within a relatively small volume of device 10 without allowing electromagnetic interference with the operation of phased antenna array 60 at millimeter and centimeter wave frequencies. The example of
In order to dissipate heat associated with performing wireless communications at millimeter and centimeter wave frequencies (e.g., heat generated by phased antenna array 60), a heat spreader structure such as heat spreader 140 may be coupled to conductive rear wall 138 of conductive cavity 132. Heat spreader 140 may include metal or other materials having a relatively high thermal conductivity. Heat spreader 140 and may serve as a heat sink for the heat generated by phased antenna array 60 (and may therefore sometimes be referred to herein as heat sink 140) or may serve to convey or dissipate heat from cavity 128 and conductive cavity 132 to other portions of device 10 (e.g., portions of device 10 far from transceiver 28 of
Heat spreader 140 may, for example, include fin structures to maximize the surface area of heat spreader 140 that is exposed to air (e.g., to maximize cooling rates for phased antenna array 60) or may include any other desired heat spreading structures. If desired, heat spreader 140 may be coupled to conductive rear wall 138 using adhesive, thermal paste, screws, pins, and/or any other desired interconnecting structures. Heat spreader 140 serve as part of the ground for antennas 40 if desired. The example of
As shown in
Conductive cavity 132 may include conductive sidewalls 146 and 148 extending between conductive sidewalls 136 and 134. Conductive sidewalls 146 and 148 extend vertically from conductive rear wall 138 (e.g., towards dielectric layer 122 of
In this way, conductive cavity 132 may have a rectangular lateral shape (e.g., in the X-Y plane of
Substrate 124 is mounted to conductive rear wall 138 of conductive cavity 132. In the example of
As shown in the example of
Each patch element 104 includes a first positive antenna feed terminal 98V coupled to that patch element at edge 162 and a second positive antenna feed terminal 98H coupled to that patch element at edge 164. In this way, each patch element 104 can convey radio-frequency signals with first and second orthogonal linear polarizations (e.g., vertical and horizontal polarizations). However, when arranged in this way, the asymmetry of conductive cavity 132 due to conductive sidewall 146 being located closer to positive antenna feed terminals 98V than positive antenna feed terminals 98H may cause conductive cavity 132 to load the impedance of one polarization for phased antenna array 60 more than the other polarization (e.g., conductive cavity 132 may load the impedance of positive antenna feed terminals 98V differently than 98H). While the shape of conductive cavity 132 can be tweaked to load positive antenna feed terminals 98V with a desired impedance, doing so would generate a non-proportionate change in the impedance of positive antenna feed terminals 98H. Similarly, the shape of conductive cavity 132 can be tweaked to load positive antenna feed terminals 98H with a desired impedance, but doing so would generate a non-proportionate change in the impedance of positive antenna feed terminals 98V. This loading asymmetry across polarizations for phased antenna array 60 can limit the overall antenna efficiency for phased antenna array 60 in one of the polarizations during wireless communications.
In order to mitigate these effects, the antennas 40 in phased antenna array 60 may be oriented as shown in the top-down view of
For example, edges 160 and 164 of each patch element 104 may extend parallel to axis 168 of
While patch elements 104 are rotated at non-parallel angles with respect to the conductive sidewalls of conductive cavity 132, the center of each patch element 104 may be located at the same distance 172 from both conductive sidewalls 146 and 148. Distance 172 may be approximately equal to one-half of the wavelength of operation of phased antenna array 60 (e.g., one-half of an effective wavelength compensated for dielectric loading effects from substrate 124). The center of antenna 40-1 may be located at distance 170 from conductive sidewall 136 and the center of antenna 40-N may be located at distance 170 from conductive sidewall 134. Distance 170 may, for example, be equal to distance 172 (e.g., distance 170 may be approximately one-half of the wavelength of operation of phased antenna array 60).
When oriented in this way, each positive antenna feed terminal 98V and 98H in phased antenna array 60 may be located at approximately the same distance from conductive sidewall 146. Similarly, each positive antenna feed terminal 98V and 98H in phased antenna array 60 may be located at approximately the same distance from conductive sidewall 148. This symmetry may allow conductive cavity 132 to load the impedance of one polarization for phased antenna array 60 the same as the other polarization (e.g., conductive cavity 132 may load the impedance of positive antenna feed terminals 98V the same as positive antenna feed terminals 98H). Any adjustment to conductive cavity 132 will therefore affect impedance loading across both polarizations equally. This balance in impedance loading across polarizations for phased antenna array 60 may serve to maximize the overall antenna efficiency for phased antenna array 60 for both of the polarizations.
The example of
If desired, parasitic antenna resonating elements may be mounted over patch elements 104 in phased antenna array 60. The parasitic antenna resonating elements may be cross-shaped patches having arms that extend parallel to axes 168 and 166 (e.g., the arms may overlap positive antenna feed terminals 98V and 98H in patch elements 104). The parasitic antenna resonating elements may serve to broaden the bandwidth of antennas 40. Patch antennas 40 that are provided with parasitic antenna resonating elements in this way may sometimes be referred to as stacked patch antennas.
Curve 176 illustrates the performance of both polarizations covered by phased antenna array 60 having patch elements 104 that are rotated with respect to the sidewalls of conductive cavity 132 (e.g., as shown in
The example of
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.