Abstract: An electronic device may have first and second rear-facing displays, a front-facing display, a cover at a front side overlapping the front-facing display, and an antenna that radiates through the cover. The antenna may be formed from sheet metal. The antenna may have a resonating element formed from a first portion of the sheet metal and an antenna ground that includes a second portion of the sheet metal separated from the first portion by a cavity. A third portion of the sheet metal may couple the first portion to the second portion and may be folded around the cavity to produce a spring force that presses the first portion against the cover. The first portion and the cover may have the same compound curvature. The second portion may form a conductive cavity for the antenna.

Abstract: An electronic device may include a phased antenna array. The array may include co-located first and second antennas formed on a dielectric substrate. The first antenna may include a first patch element and multi-layer parasitic structures. The multi-layer parasitic structures may include a first set of co-planar parasitic elements. The first set of parasitic elements may overlap the first patch element and may be separated by a gap. The multi-layer parasitic structures may include an additional parasitic element that overlaps the gap. The second antenna may include a second patch element that is co-planar with the additional parasitic patch. The second patch element may at least partially overlap one of the parasitic elements in the first set. The first and second patch antennas may collectively cover first and second frequency bands while occupying a minimal amount of space on the dielectric substrate.

Abstract: A head-mounted device may have a head-mounted housing. The head-mounted housing may have displays that display images for a user through lenses. The displays and lenses may be mounted in left and right optical modules. Attachment structures such as magnets may be used to removably attach left and right vision correction lenses to the left and right optical modules, respectively. The images may be viewed from eye boxes through the vision correction lenses while the head-mounted device is being worn by the user. The vision correction lenses and the head-mounted device may be provided with near-field communications antennas. The antennas may be formed from coils that surround corrective lens elements in the vision correction lenses. In the head-mounted device, antennas may be formed from coils surrounding the lenses in the optical modules and/or may include other coil(s).

Abstract: A head-mounted device such as a pair of glasses may have display systems. The display systems may present images to eye boxes for viewing by a user. The glasses may have clear lenses through which real-world objects may be viewed from the eye boxes. The glasses may have a metal frame that surrounds the lenses and may have temples that are coupled to the frame using hinges. Radio-frequency transceiver circuitry such as cellular telephone transceiver circuitry may be coupled to one or more antennas in the head-mounted device. The antennas may have antenna resonating elements formed by placing dielectric-filled gaps in the metal frame to divide the frame into segments. Antenna resonating elements formed from segments of the metal frame may be coupled to the radio-frequency transceiver circuitry using transmission lines.

Abstract: An electronic device may be provided with a sidewall, a rear wall, a cover layer mounted to the sidewall, and a display panel mounted to the cover layer. A conductive mesh may be layered onto the cover layer within a gap between the panel and the sidewall. The device may include an antenna with a radiating cavity and a radiating slot overlapping the radiating cavity. The radiating slot may have opposing edges defined by the conductive mesh and the display panel. The radiating cavity may have edges defined by the sidewall, the display panel, the conductive mesh, the rear wall, and an air loop gasket. The radiating cavity and the radiating slot may be fed by a coplanar waveguide that overlaps the radiating slot.

Abstract: An electronic device may be provided with an antenna module having a substrate. A phased antenna array of dielectric resonator antennas and a radio-frequency integrated circuit for the array may be mounted to one or more surfaces of the substrate. The dielectric resonator antennas may include dielectric columns excited by feed probes. The feed probes may be printed onto sidewalls of the dielectric columns or may be pressed against the sidewalls by biasing structures. A plastic substrate may be molded over each dielectric column and each of the feed probes in the array. The feed probes may cover multiple polarizations. The array may include elements for covering multiple frequency bands. The dielectric columns may be aligned a longitudinal axis and may be rotated at a non-zero and non-perpendicular angle with respect to the longitudinal axis.

Abstract: An electronic device may have a phased antenna array. An antenna in the array may include a rectangular patch element with diagonal axes. The antenna may have first and second antenna feeds coupled to the patch element along the diagonal axes. The antenna may be rotated at a forty-five degree angle relative to other antennas in the array. The antenna may have one or two layers of parasitic elements overlapping the patch element. For example, the antenna may have a layer of coplanar parasitic patches separated by a gap. The antenna may also have an additional parasitic patch that is located farther from the patch element than the layer of coplanar parasitic patches. The additional parasitic patch may overlap the patch element and the gap in the coplanar parasitic patches. The antenna may exhibit a relatively small footprint and minimal mutual coupling with other antennas in the array.

Abstract: An electronic device may have a phased antenna array. An antenna in the array may include a rectangular patch element with diagonal axes. The antenna may have first and second antenna feeds coupled to the patch element along the diagonal axes. The antenna may be rotated at a forty-five degree angle relative to other antennas in the array. The antenna may have one or two layers of parasitic elements overlapping the patch element. For example, the antenna may have a layer of coplanar parasitic patches separated by a gap. The antenna may also have an additional parasitic patch that is located farther from the patch element than the layer of coplanar parasitic patches. The additional parasitic patch may overlap the patch element and the gap in the coplanar parasitic patches. The antenna may exhibit a relatively small footprint and minimal mutual coupling with other antennas in the array.

Abstract: An electronic device such as a head-mounted display device may include an antenna that radiates through a cover. The antenna may have an antenna resonating element layered onto the cover and having a three-dimensional curvature. The antenna resonating element may have an antenna ground. A pressure-activated connector may electrically couple the antenna resonating element to the antenna ground. If desired, the pressure-activated connector may lock the antenna resonating element to the antenna ground. The pressure-activated connector may include a metal finger, a metal spring, a metal ball, a curling metal receptacle, a dimple, a metal screw, a screw receptacle, metal burs, and/or rotational locking structures. The pressure-activated connector may form a robust mechanical connection between the first and second conductors despite the curvature of the antenna resonating element, which minimizes electrical discontinuities that can otherwise deteriorate antenna performance.

Abstract: A head-mounted device may have a housing with a cover having three-dimensional curvature. A front-facing display may be mounted to the cover and may display images through the cover. The cover may have a peripheral region laterally surrounding the front-facing display. An antenna may have an antenna resonating element layered onto the cover overlapping the peripheral region. The antenna may be switchable between a first polarization state and a second polarization state. In the first polarization state, the antenna conveys radio-frequency signals having a first polarization with an earbud. In the second polarization state, the antenna conveys radio-frequency signals having a second polarization with the earbud. One or more processors may gather wireless performance metric data from the radio-frequency signals and may adjust the antenna between the polarization states to optimize the wireless performance metric data.

Abstract: A head-mounted device may have a housing with a cover having three-dimensional curvature. A front-facing display may be mounted to the cover and may display images through the cover. The cover may have a peripheral region laterally surrounding the front-facing display. An antenna may have an antenna resonating element layered onto the cover overlapping the peripheral region. The antenna may be switchable between different radiation patterns. A controller may gather wireless performance metric data for each of the radiation patterns. The antenna may be switched to exhibit a radiation pattern that optimizes the wireless performance metric data. This may serve to minimize interference from external devices operating using the same ultra-low-latency audio communications protocol as the antenna.

Abstract: An electronic device such as a head-mounted display device may include an antenna that radiates through a cover. The antenna may have a ground and an antenna resonating element layered onto the cover. The ground may include conductive structures separated from the resonating element by a volume. The device may include a fan that conveys air through a vent in a chassis of the electronic device through a tunnel. The tunnel may be free from conductive material and may extend through the volume of the antenna. The fan may include blades enclosed within metal walls. A conductive mesh may be coupled between the metal walls and may separate the blades from the tunnel. This may serve to extend the volume of the antenna to also include at least some of the volume of the fan, thereby maximizing efficiency bandwidth of the antenna without sacrificing thermal dissipation by the fan.

Abstract: An electronic device may have first and second rear-facing displays, a front-facing display, a cover at a front side overlapping the front-facing display, and an antenna that radiates through the cover. The cover may have a three-dimensional curvature. The device may have an inner chassis and an outer chassis. The antenna may include a radiating element and a ground trace on a flexible printed circuit. To maximize wireless performance of the antenna, the ground trace may be electrically coupled to as much conductive material in the vicinity of the antenna as possible. For example, the ground trace may be grounded to conductive structures in the front-facing display via a conductive cavity for the antenna, may be grounded directly to the outer chassis using conductive screws, and/or may be grounded directly to the inner chassis using conductive screws.

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 have a cover layer and an antenna. A dielectric adapter may have a first surface coupled to the antenna and a second surface pressed against the cover layer. The cover layer may have a three-dimensional curvature. The second surface may have a curvature that matches the curvature of the cover layer. Biasing structures may exert a biasing force that presses the antenna against the dielectric adapter and that presses the dielectric adapter against the cover layer. The biasing force may be oriented in a direction normal to the cover layer at each point across dielectric adapter. This may serve to ensure that a uniform and reliable impedance transition is provided between the antenna and free space through the cover layer over time, thereby maximizing the efficiency of the antenna.

Abstract: An electronic device may have first and second rear-facing displays, a front-facing display, a cover at a front side overlapping the front-facing display, and an antenna that radiates through the cover. The antenna may be formed from traces on a flexible printed circuit. The antenna may be provided with a conductive shield on a dielectric carrier. The flexible printed circuit may be mounted to the carrier opposite the shield. A biasing member may be mounted to the carrier and may press the flexible printed circuit against the cover. To minimize weight of the device, the shield may be formed from conductive traces patterned onto the carrier. The carrier may include first and second substrates formed from respective shots of co-molded plastic. The second substrate may include plateable grade plastic and the conductive traces may be patterned onto plateable outer surfaces of the second substrate opposite the first substrate.

Abstract: An electronic device may have first and second rear-facing displays, a front-facing display, a cover layer at a front side with a central region overlapping the front-facing display and a peripheral region, and wireless circuitry with a transceiver and antennas. The transceiver may convey audio data with left and right earbuds using a non-Bluetooth low-latency-audio communications protocol. The antenna(s) may be mounted at a bottom side of the device overlapping the peripheral region, at a rear side of the device, or may be mounted to a head strap. The antenna(s) may be tilted to optimize field(s) of view, to match polarization of the earbuds, and/or to allow multiple antennas to exhibit orthogonal polarizations. The antennas may include a single antenna that concurrently conveys packets of audio data to both earbuds or may include first and second antennas that concurrently convey audio data to the left and right earbuds.

Abstract: An electronic device may have first and second rear-facing displays, a front-facing display, a cover at a front side overlapping the front-facing display, and an antenna that radiates through the cover. The antenna may be formed from sheet metal. The antenna may have a resonating element formed from a first portion of the sheet metal and an antenna ground that includes a second portion of the sheet metal separated from the first portion by a cavity. A third portion of the sheet metal may couple the first portion to the second portion and may be folded around the cavity to produce a spring force that presses the first portion against the cover. The first portion and the cover may have the same compound curvature. The second portion may form a conductive cavity for the antenna.

Abstract: A head-mounted device may have a head-mounted housing. The head-mounted housing may have rear-facing displays that display images for a user. The images are viewable from eye boxes while the head-mounted device is being worn by the user. A peripheral conductive member may run along a peripheral edge of the front face of the housing. Dielectric-filled gaps may divide the peripheral conductive member into elongated conductive segments. The conductive segments may form antenna resonating elements for antennas on the front face. Radio-frequency transceiver circuitry such as cellular telephone transceiver circuitry may be coupled to the antennas.

Abstract: A head-mounted device may have a head-mounted housing that is configured to be worn on a head of a user. While the head-mounted device is being worn, left and right displays in optical modules in the head-mounted device may provide images to eye boxes located rearward of the head-mounted device. A forward-facing publicly viewable display on a front portion of the head-mounted device may be covered with a transparent housing portion forming a display cover layer. Millimeter wave antennas may be mounted under a dielectric member that is interposed between the antennas and an edge portion of the transparent housing portion. The antennas may have planar outer surfaces. The dielectric member may have a planar surface separated from the planar outer surfaces by air gaps and a curved outer surface.