Abstract: An electronic device may be provided with wireless communications circuitry and control circuitry. The wireless communications circuitry may include centimeter and millimeter wave transceiver circuitry and a phased antenna array. A dielectric cover may be formed over the phased antenna array. The phased antenna array may transmit and receive antenna signals through the dielectric cover. The dielectric cover may have a surface that faces the phased antenna array and may have a curvature. The antenna elements of the phased antenna array may be formed on a dielectric substrate. The dielectric substrate may have one or more thinned regions between antenna elements of the phased antenna array to reduce surface wave interference between adjacent antennas. The dielectric substrate may have a smaller thickness in the thinned region than in the regions under the antenna elements. The dielectric substrate may be totally removed in the thinned region.

Abstract: An electronic device may include a phased antenna array mounted in a conductive cavity for conveying radio-frequency signals above 10 GHz. The cavity may include sidewalls extending from a rear wall. The array may include rectangular patches each having first and second perpendicular edges. Each of the first edges in the array may be aligned with a first axis. Each of the second edges in the array may be aligned with a second axis perpendicular to the first axis. The first and second axes may be oriented at 45 degrees with respect to each of the sidewalls of the cavity. Each patch may be fed using first and second positive antenna feed terminals that cover orthogonal linear polarizations. The cavity may prevent interference while symmetrically loading the impedance of both the first and second positive antenna feed terminals in each patch.

Abstract: An electronic device such as a wristwatch may be provided with wireless circuitry and a display having a display module and a cover layer. The display module may include a dielectric layer. Touch sensor electrodes may be formed from conductive traces on the dielectric layer. An antenna may be embedded within the display module. The antenna may include an antenna resonating element formed from a grid of intersecting conductive traces on the dielectric layer. The grid may have edges that define a lateral outline of the antenna resonating element. The outline may have a length that configures the antenna to radiate at a desired frequency. The antenna resonating element may be formed from indium tin oxide and may be substantially transparent.

Abstract: An electronic device may be provided with wireless circuitry. The wireless circuitry may include one or more antenna structures and transceiver circuitry such as millimeter wave transceiver circuitry. Antenna structures in the wireless circuitry may include patch antennas that are organized in a phased antenna array. Each patch antenna may include an antenna resonating element and a parasitic element. The parasitic element for the patch antenna may have dielectric-filled openings formed between coplanar parasitic conductors. The parasitic conductors may include a central parasitic conductor, four rectangular parasitic conductors formed around the central parasitic conductor, and corner parasitic conductors formed at the corners of the parasitic element. The corner parasitic conductors may be non-rectangular. For example, the corner parasitic conductors may have first and second perpendicular edges and a straight or curved third edge that joins the first and second edges.

Abstract: An electronic device may have a display. A display cover layer and a transparent inner display member may overlap a display pixel layer. The display pixel layer may have an array of display pixels for displaying images for a user. A touch sensor layer may be interposed between the display pixel layer and the transparent display member. A ferromagnetic shielding layer may be mounted below the display pixel layer. A flexible printed circuit containing coils of metal signal lines that form a near-field communications loop antenna may be interposed between the ferromagnetic shielding layer and the display pixel layer. A non-near-field antenna such as an inverted-F antenna may have a resonating element mounted on an inner surface of the display cover layer. The resonating element may be interposed between the transparent display member and the display cover layer.

Abstract: An electronic device may be provided with a dielectric cover layer, a dielectric substrate, and a phased antenna array on the dielectric substrate for conveying millimeter wave signals through the dielectric cover layer. The array may include conductive traces mounted against the dielectric layer. The conductive traces may form patch elements or parasitic elements for the phased antenna array. The dielectric layer may have a dielectric constant and a thickness selected to form a quarter wave impedance transformer for the array at a wavelength of operation of the array. The substrate may include fences of conductive vias that laterally surround each of the antennas within the array. When configured in this way, signal attenuation, destructive interference, and surface wave generation associated with the presence of the dielectric layer over the phased antenna array may be minimized.

Abstract: An electronic device may be provided with a dielectric cover layer and a conductive layer on the dielectric cover layer. The conductive layer may define an opening. A dielectric spacer may be mounted to the cover layer within the opening. A substrate may be mounted to the spacer. Vertical conductive structures may extend from the conductive layer to the substrate and may laterally surround the spacer. A phased antenna array may be formed on the substrate and aligned with the opening. The cover layer may have a dielectric constant and thickness that are selected to form a quarter wave impedance transformer for the array at a wavelength of operation of the array. The spacer and the conductive structures may exhibit a cavity resonance at the wavelength. The array and the conductive structures may radiate radio-frequency signals at millimeter wave frequencies through the dielectric cover layer.

Abstract: An electronic device may be provided with a phased antenna array for conveying millimeter wave signals. The array may be mounted to a substrate that includes transmission line layers having a first dielectric permittivity and antenna layers having a second dielectric permittivity that is less than the first dielectric permittivity. A ground plane may be interposed between the antenna layers and the transmission line layers. The array may be mounted to the antenna layers and transceiver circuitry may be mounted to the transmission line layers. Transmission line traces may be formed on the transmission line layers. The relatively high permittivity of the first set of dielectric layers may allow the transmission line traces to be routed relatively close together with minimal electromagnetic interference. The relatively low permittivity of the second set of dielectric layers may allow the array to operate with satisfactory antenna efficiency, gain, and bandwidth.

Abstract: An electronic device such as a wristwatch may have a housing with metal portions such as metal sidewalls. The housing may form an antenna ground for an antenna. An antenna resonating element for the antenna may be formed from a stack of capacitively coupled component layers such as a display layer, touch sensor layer, and near-field communications antenna layer at a front face of the device. An additional antenna may be formed from a peripheral resonating element that runs along a peripheral edge of the device and the antenna ground. A rear face antenna may be formed using a wireless power receiving coil as a radio-frequency antenna resonating element or may be formed from metal antenna traces on a plastic support for light-based components.

Abstract: An electronic device may be provided with wireless communications circuitry and control circuitry. The wireless communications circuitry may include millimeter wave transceiver circuitry and a phased antenna array. The phased antenna array may transmit and receive millimeter wave signals. Beam steering circuitry may be coupled to the phased antenna array and may be adjusted to steer the millimeter wave signals in a particular direction. The control circuitry may track the location of an external device using sensor data. The control circuitry may control a mechanical positioner to mechanically adjust an orientation of the phased antenna array and/or may control the beam steering circuitry to steer the millimeter wave signals towards the location of the external device. In this way, a line of sight millimeter wave communications link may be maintained between the phased antenna array and the external device even if the external device moves over time.

Abstract: An electronic device such as a wristwatch may have a housing with metal portions such as metal sidewalls. The housing may form an antenna ground for an antenna. An antenna resonating element for the antenna may be formed from a stack of capacitively coupled component layers such as a display layer, touch sensor layer, and near-field communications antenna layer at a front face of the device. An additional antenna may be formed from a peripheral resonating element that runs along a peripheral edge of the device and the antenna ground. A rear face antenna may be formed using a wireless power receiving coil as a radio-frequency antenna resonating element or may be formed from metal antenna traces on a plastic support for light-based components.

Abstract: An electronic device may be provided with wireless communications circuitry and control circuitry. The wireless communications circuitry may include centimeter and millimeter wave transceiver circuitry and a phased antenna array. A dielectric cover may be formed over the phased antenna array. The phased antenna array may transmit and receive antenna signals through the dielectric cover. The dielectric cover may have first and second opposing surfaces. The second surface may face the phased antenna array and may have a curvature. The antenna elements of the phased antenna array may be formed on a dielectric substrate. The dielectric substrate may have one or more thinned regions between antenna elements of the phased antenna array to promote bending. The dielectric substrate may have a smaller thickness in the thinned region than in the regions under the antenna elements. The dielectric substrate may be totally removed in the thinned region.

Abstract: An electronic device may communicate with an external device and may include one or more phased antenna arrays that transmit and receive a beam of millimeter wave signals. Beam steering circuitry may be coupled to the phased antenna array and may be adjusted to steer a direction of the beam. Control circuitry may control the beam steering circuitry to sweep the beam of millimeter wave signals over multiple beam directions. The control circuitry may gather wireless performance data and may compare the wireless performance metric data at each beam direction in the sweep prior to gathering wireless performance metric data at other beam directions in the sweep. The first beam direction in the sweep may be selected based on an initial position of the external device and/or based on sensor data gathered by the control circuitry.

Abstract: An electronic device may have a display cover layer mounted to a metal housing. Electrical component layers such as a display layer, touch sensor layer, and near-field communications antenna layer may be mounted under the display cover layer. An antenna feed may have a positive feed terminal coupled to the electrical component layers and a ground feed terminal coupled to the metal housing. The electrical component layers may serve as an antenna resonating element for an antenna. The antenna may cover cellular telephone bands and may receive satellite navigation system signals. A system-in-package device may be mounted to the metal housing. A flexible printed circuit may extend between the electrical component layers and the system-in-package device. A mounting bracket for the system-in-package device may be provided with electrical isolation to enhance antenna performance in bands such as a satellite navigation system band.

Abstract: An electronic device may be provided with wireless communications circuitry and control circuitry. The wireless communications circuitry may include centimeter and millimeter wave transceiver circuitry and a phased antenna array. A dielectric cover may be formed over the phased antenna array. The phased antenna array may transmit and receive wireless radio-frequency signals through the dielectric cover. The dielectric cover may have first and second opposing surfaces. The second surface may face the phased antenna array and may have a curvature. The curvature of the second surface may include one or more recessed regions of the dielectric cover. The one or more recessed regions of the second surface may serve to maximize and broaden the coverage area for the phased antenna array. The first surface may be conformal to other structures in the electronic device.

Abstract: An electronic device may be provided with wireless communications circuitry and control circuitry. The wireless communications circuitry may include centimeter wave and millimeter wave transceiver circuitry and a phased antenna array. The phased antenna array may transmit and receive wireless signals having a frequency higher than 10 GHz. Beam steering circuitry may be coupled to the phased antenna array and may be adjusted to steer the wireless signals to communicate with external equipment. Sensor circuitry in the electronic device may gather sensor data. The control circuitry may use the gathered sensor data to determine a polarization mismatch between the electronic device and the external equipment (e.g., between a signal transmitting device and a signal receiving equipment or vice versa). To mitigate the polarization mismatch data loss, the control circuitry may adjust the polarization settings associated with antennas of the electronic device.

Abstract: An electronic device may be provided with wireless communications circuitry and control circuitry. The wireless communications circuitry may include centimeter and millimeter wave transceiver circuitry and a phased antenna array. A dielectric cover may be formed over the phased antenna array. The phased antenna array may transmit and receive antenna signals through the dielectric cover. The dielectric cover may have a surface that faces the phased antenna array and may have a curvature. The antenna elements of the phased antenna array may be formed on a dielectric substrate. The dielectric substrate may have one or more thinned regions between antenna elements of the phased antenna array to reduce surface wave interference between adjacent antennas. The dielectric substrate may have a smaller thickness in the thinned region than in the regions under the antenna elements. The dielectric substrate may be totally removed in the thinned region.

Abstract: A wireless power transmission system has a wireless power receiving device that is configured to receive power from a wireless power transmitting device. The power transmitting device may have a conductive housing portion at a front face and a reflector at a rear face that form a cavity for an antenna that is configured to transmit wireless charging signals to the power receiving device. The power transmitting device may be a desktop computer. The power receiving device may include an antenna that receives signals from the power transmitting device and rectifier circuitry that converts signals from the antenna to corresponding rectified direct current voltage signals that may be used to charge a battery in the power receiving device. The antenna may include a cavity formed from a conductive housing for the power receiving device. The power receiving device may be an accessory such as a keyboard, trackpad, or computer mouse.

Abstract: An electronic device may be provided with wireless communications circuitry and control circuitry. The wireless communications circuitry may include centimeter and millimeter wave transceiver circuitry and a phased antenna array. A dielectric cover may be formed over the phased antenna array. The phased antenna array may transmit and receive antenna signals through the dielectric cover. The dielectric cover may have first and second opposing surfaces. The second surface may face the phased antenna array and may have a curvature. The antenna elements of the phased antenna array may be formed on a dielectric substrate. The dielectric substrate may have one or more thinned regions between antenna elements of the phased antenna array to promote bending. The dielectric substrate may have a smaller thickness in the thinned region than in the regions under the antenna elements. The dielectric substrate may be totally removed in the thinned region.

Abstract: An electronic device may include a peripheral conductive housing wall. The housing wall may be patterned to form first and second continuous regions defining opposing edges of a patterned region. The patterned region may include slots that divide the wall into conductive structures between the first and second continuous regions. A tuning element for an antenna in the device may be formed from the conductive structures and the slots in the patterned region. The slots and the conductive structures in the patterned region may be configured to mitigate any excessive capacitances between the first and second continuous regions in one or more desired frequency bands to optimize antenna efficiency. The slots may be narrow enough so as to be invisible to the un-aided human eye. This may configure the first and second continuous regions to appear to a user as a single continuous piece of conductor.