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: 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 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 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 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 a conductive sidewall. An aperture may be formed in the sidewall. The sidewall may have a cavity that extends from the aperture towards the interior of the device. The cavity may be filled with an injection-molded plastic substrate. A dielectric block having a dielectric constant greater than that of the injection-molded plastic substrate and the antenna layers may be embedded in the injection-molded plastic substrate. The dielectric block may at least partially overlap an antenna. The antenna may convey radio-frequency signals at a frequency greater than 10 GHz through the cavity, the dielectric block, the injection-molded plastic substrate, and the aperture. The dielectric block may increase the effective dielectric constant of the cavity, allowing the antenna to cover relatively low frequencies without increasing the size of the aperture.

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 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: 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: 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.

Abstract: An electronic device may include first and second phased antenna arrays and a triplet of first, second, and third ultra-wideband antennas. An antenna module in the device may include a dielectric substrate. The first and second arrays and the triplet may be formed on the dielectric substrate. The third and second ultra-wideband antennas may be separated by a gap. The first array may be laterally interposed between the third and second ultra-wideband antennas within the gap. The third ultra-wideband antenna may be laterally interposed between the first phased antenna array and at least some of the second array. An integrated circuit may be mounted to the dielectric substrate using an interposer. The antenna module may occupy a minimal amount of space within the device and may be less expensive to manufacture relative to scenarios where the arrays and the ultra-wideband antennas are formed on separate substrates.

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 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 be provided with a phased antenna array on an antenna module. The array may include low band antennas and high band antennas that radiate at frequencies greater than 10 GHz. The module may include antenna layers, transmission line layers, and ground traces that separate the antenna layers from the transmission line layers. The low band antennas and the high band antennas may have radiators patterned onto the antenna layers. The radiators may be fed by transmission lines on the transmission line layers. The antenna layers may have a dielectric permittivity that is greater than the dielectric permittivity of the transmission line layers. This may serve to reduce the lateral footprint of the low band and high band antennas, which allows the antennas to be interleaved along a common linear axis in the phased antenna array, thereby minimizing the lateral footprint of the antenna module.

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 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 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.