Abstract: An electronic device may be provided with a first antenna fed by a first path and a second antenna fed by a second path. A first coupler may be disposed on the first path, a second coupler may be disposed on the second path, and a feedback path may couple the couplers to a receiver. A low-pass filter may be disposed on the second path. The first antenna may transmit signals in a low band. Some of the signals may couple onto the second antenna. The second coupler may pass the coupled signals to the receiver. Control circuitry may generate a scattering parameter value characterizing the coupling of the signals from the first antenna onto the second antenna. The scattering parameter value may be used to determine when to switch the first antenna out of use and the second antenna into use for covering the low band.

Abstract: An electronic device may have conductive sidewalls and a rear wall. The rear wall may have a first portion mounted to the sidewalls and a second portion protruding away from the first portion to define a cavity. A sensor board may be mounted within the cavity. A coil structure may be mounted within the cavity and surrounding the sensor board. An antenna may have an antenna ground separated from a patch element by an antenna volume. The patch element may include a first conductive trace on the first portion of the rear wall, a second conductive trace on the sensor board, and a conductive interconnect structure that couples the first conductive trace to the second conductive trace. The coil structure may be disposed outside of the antenna to minimize impact of the coil structure on performance of the antenna.

Abstract: An electronic device may have conductive sidewalls, a conductive turret, and a conductive bridge. The turret may be separated from the sidewalls by a slot. A display may be mounted to the turret and may include conductive display structures and a conductive ring that couples the display to the turret. An antenna in the device may have a radiating element formed from the conductive display structures, the ring, and the turret. The conductive bridge may form a short path across the slot to the sidewalls. The slot may define radiating edges of the radiating element. Integrating the antenna into the device in this way may maximize the bandwidth of the antenna by extending the antenna area to include the entire lateral area of the electronic device. This may also serve to maximize the active area of the display.

Abstract: An electronic device such as a wristwatch device may have a housing with metal sidewalls and a display module having conductive display structures. The conductive display structures may be separated from the sidewalls by a slot element for a first antenna that runs around the display module. A feed element for the first antenna may be coupled between the display structures and the sidewalls. An antenna resonating element for a second antenna may be disposed within the slot element. A printed circuit may include additional antenna elements for the second antenna. The antenna resonating element may extend away from the feed element for the first antenna to provide improved isolation between the two antennas. The first antenna may be operable to provide coverage for frequencies that are lower than frequencies for which the second antenna may be operable to provide coverage.

Abstract: An electronic device such as a wristwatch may be provided with a phased antenna array for conveying first signals at a first frequency between 10 GHz and 300 GHz and a non-millimeter wave antenna for conveying second signals at a second frequency below 10 GHz. The device may include conductive housing sidewalls and a display. Conductive structures in the display and the conductive housing sidewalls may define a slot element in the non-millimeter wave antenna. The phased antenna array may be mounted within the slot element, aligned with a spatial filter in the display, or aligned with a dielectric window in the conductive housing sidewalls. Control circuitry may process signals transmitted by the phased antenna array and a reflected version of the transmitted signals that has been received by the phased antenna array to detect a range between the device and an external object.

Abstract: An electronic device may include a rear housing wall, antenna resonating element, sensor board, and grounding ring. The grounding ring may couple antenna currents from the resonating element onto a ground trace on the sensor board. A switchable inductor may couple the grounding ring to the ground traces. The switchable inductor may be used to tune a frequency response of the antenna in a cellular low band. Additionally or alternatively, an inductor may couple the resonating element to the ground traces or other portions of an antenna ground. This inductor may serve to extend the effective length of the antenna resonating element in the cellular low band to compensate for dielectric loading by the rear housing wall, such as in examples where the rear housing wall is formed from zirconia.

Abstract: Methods and devices may be used to perform underwater communication using one or more electronic devices. The one or more electronic devices include a first wireless transceiver configured to transmit first wireless signals through an air medium with the first wireless signals not being conducive for transmission through a water medium. The one or more electronic devices also include a second wireless transceiver configured to transmit second wireless signals through water. The electronic devices detect whether at least one electronic device has been submerged, and in response to submersion, transmits at least some communication types from the second wireless transceiver rather than the second wireless transceiver.

Abstract: A wirelessly locatable tag may include a first housing member defining a first exterior surface of the tag, a second housing member removably coupled to the first housing member and defining a second exterior surface of the tag, and an antenna assembly. The antenna assembly may include an antenna frame defining a top surface and a peripheral side surface, a first antenna on the antenna frame along the peripheral side surface and configured to communicate with the electronic device using a first wireless protocol, a second antenna on the antenna frame along the peripheral side surface and configured to send a localization signal to the electronic device using a second wireless protocol different than the first protocol, and a third antenna on the antenna frame along the top surface and configured to communicate with the electronic device via a third wireless protocol different than the first and second protocols.

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 include a rear housing wall, antenna resonating element, sensor board, and grounding ring. The grounding ring may couple antenna currents from the resonating element onto a ground trace on the sensor board. A switchable inductor may couple the grounding ring to the ground traces. The switchable inductor may be used to tune a frequency response of the antenna in a cellular low band. Additionally or alternatively, an inductor may couple the resonating element to the ground traces or other portions of an antenna ground. This inductor may serve to extend the effective length of the antenna resonating element in the cellular low band to compensate for dielectric loading by the rear housing wall, such as in examples where the rear housing wall is formed from zirconia.

Abstract: An electronic device may be provided with a housing, a logic board, and wireless circuitry on the logic board. The wireless circuitry may include first and second antennas formed from conductive traces on a surface of the logic board. The first and second antennas may include resonating element arms at opposing sides of the logic board. The first antenna may have a fundamental mode that radiates in a Bluetooth® communications band at 2.4 GHz. The second antenna may radiate in a first ultra-wideband communications band such as a 6.5 GHz ultra-wideband communications band. If desired, the second antenna may also radiate in a second ultra-wideband communications band such as an 8.0 GHz ultra-wideband communications band. In another suitable arrangement, a harmonic mode of the first antenna may radiate in the second ultra-wideband communications band.

Abstract: An electronic device may include a rear housing wall, antenna resonating element, coil, sensor board, and antenna grounding ring structures. The coil may receive wireless charging signals through the grounding ring structures and the rear housing wall. The grounding ring structures may include concentric ring-shaped traces. The ring-shaped traces may be separated by at least one gap. The ring-shaped traces and the gaps may configure the grounding ring structures to short antenna currents at relatively high frequencies from the antenna resonating element to a ground trace on the sensor board while blocking currents at relatively low frequencies. This may allow the ground trace to form part of an antenna without substantially impairing wireless charging efficiency of the coil.

Abstract: Embodiments disclosed herein describe a wireless power receiving system for an electronic device includes: a first inductor coil configured to receive power primarily at a first frequency and from magnetic fields propagating in a first direction; and a second inductor coil configured to receive power primarily at a second frequency and from magnetic fields propagating in a second direction, wherein the first frequency is different than the second frequency.

Abstract: An electronic device such as a wristwatch device may have a housing with metal sidewalls and a display module having conductive display structures. The conductive display structures may be separated from the sidewalls by a slot element for a first antenna that runs around the display module. A feed element for the first antenna may be coupled between the display structures and the sidewalls. An antenna resonating element for a second antenna may be disposed within the slot element. A printed circuit may include additional antenna elements for the second antenna. The antenna resonating element may extend away from the feed element for the first antenna to provide improved isolation between the two antennas. The first antenna may be operable to provide coverage for frequencies that are lower than frequencies for which the second antenna may be operable to provide coverage.

Abstract: An electronic device may have a housing with metal sidewalls. One of the metal sidewalls may have an opening. The electronic device may have a speaker module that has a speaker housing member. Conductive structures on the speaker housing member may have an opening that forms a slot element. The opening of the metal sidewall may be aligned with slot element. The slot element and an interior cavity of the speaker housing member may form a cavity-backed slot antenna. An antenna feed structure may be disposed at the opening of the speaker housing member. An antenna feed may be directly coupled to the antenna feed structure. The antenna feed structure may indirectly feed the slot antenna resonating element by capacitive coupling. A sealing member may be disposed at the opening of the metal sidewall.

Abstract: Aspects of the subject technology relate to electronic devices with antennas. The antenna may be a display-integrated antenna. An antenna feed for the antenna may be located in a recess in a sidewall of a housing of the device. The antenna feed may be coupled to transceiver circuitry on a logic board of the device by a pair of flex circuits. A first one of the pair of flex circuits may form a portion of an antenna feed assembly. A second one of the pair of flex circuits may be an impedance-matching flex having an end that is soldered to the main logic board. The antenna may be coupled to a conductive portion of the housing of the device.

Abstract: An electronic device may have a housing with metal sidewalls. One of the metal sidewalls may have an opening. The electronic device may have a speaker module that has a speaker housing member. Conductive structures on the speaker housing member may have an opening that forms a slot element. The opening of the metal sidewall may be aligned with slot element. The slot element and an interior cavity of the speaker housing member may form a cavity-backed slot antenna. An antenna feed structure may be disposed at the opening of the speaker housing member. An antenna feed may be directly coupled to the antenna feed structure. The antenna feed structure may indirectly feed the slot antenna resonating element by capacitive coupling. A sealing member may be disposed at the opening of the metal sidewall.

Abstract: An electronic device may include a rear housing wall, antenna resonating element, coil, sensor board, and antenna grounding ring structures. The coil may receive wireless charging signals through the grounding ring structures and the rear housing wall. The grounding ring structures may include concentric ring-shaped traces. The ring-shaped traces may be separated by at least one gap. The ring-shaped traces and the gaps may configure the grounding ring structures to short antenna currents at relatively high frequencies from the antenna resonating element to a ground trace on the sensor board while blocking currents at relatively low frequencies. This may allow the ground trace to form part of an antenna without substantially impairing wireless charging efficiency of the coil.

Abstract: An electronic device may be provided with a housing, a logic board, and wireless circuitry on the logic board. The wireless circuitry may include first and second antennas formed from conductive traces on a surface of the logic board. The first and second antennas may include resonating element arms at opposing sides of the logic board. The first antenna may have a fundamental mode that radiates in a Bluetooth® communications band at 2.4 GHz. The second antenna may radiate in a first ultra-wideband communications band such as a 6.5 GHz ultra-wideband communications band. If desired, the second antenna may also radiate in a second ultra-wideband communications band such as an 8.0 GHz ultra-wideband communications band. In another suitable arrangement, a harmonic mode of the first antenna may radiate in the second ultra-wideband communications band.

Abstract: An electronic device such as a wristwatch may be provided with a phased antenna array for conveying first signals at a first frequency between 10 GHz and 300 GHz and a non-millimeter wave antenna for conveying second signals at a second frequency below 10 GHz. The device may include conductive housing sidewalls and a display. Conductive structures in the display and the conductive housing sidewalls may define a slot element in the non-millimeter wave antenna. The phased antenna array may be mounted within the slot element, aligned with a spatial filter in the display, or aligned with a dielectric window in the conductive housing sidewalls. Control circuitry may process signals transmitted by the phased antenna array and a reflected version of the transmitted signals that has been received by the phased antenna array to detect a range between the device and an external object.