Abstract: Methods and devices useful in radio frequency (RF) signal transmission are provided. By way of example, a wireless electronic device may include a transceiver, and an enclosure in which the transceiver is disposed. The enclosure may include an RF transparent layer and an RF opaque coating disposed on the RF transparent layer, where the RF opaque coating includes a pattern formed therein to enable RF signals to pass therethrough.

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.

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 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 may have a housing and other structures that form an antenna ground for an antenna. An antenna resonating element arm for the antenna may extend along the periphery of the housing. The resonating element arm may have opposing first and second ends. A return path may couple the resonating element arm to the antenna ground at the first end. An antenna feed may be coupled between the resonating element arm and the antenna ground in parallel with the return path. Electrical components such as first and second capacitors may be coupled between the antenna resonating element arm and the antenna ground. A first of the capacitors may be coupled between the antenna resonating element arm and the antenna ground at a location between the first and second ends. A second of the capacitors may be coupled between the second end and the antenna ground.

Abstract: An electronic device may include a substrate and a conductive layer on the substrate. The conductive layer may be patterned to form a first region and a second region that surrounds and defines the shape of the first region. The first region may be formed from a continuous portion of the conductive layer. The second region may include a grid of openings that divides the conductive layer into an array of patches. The first region may form an antenna resonating element for an antenna. The second region may block antenna currents from the antenna resonating element and may be transparent to radio-frequency electromagnetic waves. The openings may have a width that is too narrow to be discerned by the human eye. This may configure the first and second regions to appear as a single continuous conductive layer despite the fact that an antenna resonating element is formed therein.

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 an antenna for providing coverage in wireless communications bands of interest such as a low frequency communications band and a high frequency communications band. The antenna may have an antenna ground and an antenna resonating element. The antenna resonating element may have a high band arm that contributes to a first high band resonance in the high band and may have a low band arm that exhibits a low band resonance in the low band. A passive filter that is coupled between first and second portions of the antenna resonating element may be configured to exhibit a short circuit impedance associated with a bypass path that allows the antenna resonating element to contribute to a second high band resonance in the high band. A tunable inductor coupled to the antenna resonating element may be used to tune the low band resonance.

Abstract: Methods and devices useful in radio frequency (RF) signal transmission are provided. By way of example, a wireless electronic device may include a transceiver, and an enclosure in which the transceiver is disposed. The enclosure may include an RF transparent layer and an RF opaque coating disposed on the RF transparent layer, where the RF opaque coating includes a pattern formed therein to enable RF signals to pass therethrough.

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 have a housing and other structures that form an antenna ground for an antenna. An antenna resonating element arm for the antenna may extend along the periphery of the housing. The resonating element arm may have opposing first and second ends. A return path may couple the resonating element arm to the antenna ground at the first end. An antenna feed may be coupled between the resonating element arm and the antenna ground in parallel with the return path. Electrical components such as first and second capacitors may be coupled between the antenna resonating element arm and the antenna ground. A first of the capacitors may be coupled between the antenna resonating element arm and the antenna ground at a location between the first and second ends. A second of the capacitors may be coupled between the second end and the antenna ground.

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 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 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 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 electrical components mounted in a housing. The electronic device may include wireless transceiver circuitry and antenna structures. A display may be mounted in the housing. The display may have a transparent layer such as display cover layer. The display cover layer may have an inner surface with a recess. The recess may be a groove that runs along a peripheral edge of the display cover layer. An antenna structure such as an inverted-F antenna resonating element may be formed from a metal trace on a plastic support structure. The metal trace and support structure may be mounted in the groove with adhesive. The housing may be a metal housing that forms an antenna ground. Springs may be used in forming an antenna feed and an antenna return path that couples the antenna resonating element to ground.

Abstract: An electronic device may have an antenna for providing coverage in wireless communications bands of interest such as a low frequency communications band and a high frequency communications band. The antenna may have an antenna ground and an antenna resonating element. The antenna resonating element may have a high band arm that contributes to a first high band resonance in the high band and may have a low band arm that exhibits a low band resonance in the low band. A passive filter that is coupled between first and second portions of the antenna resonating element may be configured to exhibit a short circuit impedance associated with a bypass path that allows the antenna resonating element to contribute to a second high band resonance in the high band. A tunable inductor coupled to the antenna resonating element may be used to tune the low band resonance.

Abstract: An electronic device may have an antenna for providing coverage in wireless communications bands of interest such as a low frequency communications band and a high frequency communications band. The antenna may have an antenna ground and an antenna resonating element. The antenna resonating element may have a high band arm that contributes to a first high band resonance in the high band and may have a low band arm that exhibits a low band resonance in the low band. A passive filter that is coupled between first and second portions of the antenna resonating element may be configured to exhibit a short circuit impedance associated with a bypass path that allows the antenna resonating element to contribute to a second high band resonance in the high band.

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 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.