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 include first and second antennas formed from respective first and second segments of a housing. The first antenna may have a first feed coupled to the first segment by a first switch and coupled to the first segment by a first conductive trace. The second antenna may have a second feed coupled to the second segment by a second switch and coupled to the second segment by a second conductive trace. The first segment may be separated from the second segment by a single gap, a data connector may pass through the second segment, and the antennas may selectively cover a low band. Alternatively, the first segment may be separated from the second segment by a third segment and two gaps, the data connector may pass through the third segment, and the first and second antennas may concurrently cover the low band.

Abstract: An electronic device may include an antenna disposed on a substrate. The antenna may include a ring of conductive traces, a fed arm, and an unfed arm. The fed arm and the unfed arm may extend from opposing segments of the ring. The ring may be coupled to ground by fences of conductive vias extending through the substrate. The first arm may have a first radiating edge. The second arm may have a second radiating edge. The first radiating edge may be separated from the second radiating edge by a gap. The first arm may indirectly feed the second arm via near-field electromagnetic coupling across the gap. The first and second arms may collectively radiate in an ultra-wideband (UWB) frequency band.

Abstract: An electronic device may be provided with peripheral conductive housing structures having first and second segments. The device may include an antenna having a resonating arm formed from the first segment, an antenna ground, and a tuning element. The tuning element may have first, second, and third terminals. The first terminal may be coupled to the second segment. The antenna may have a switchable loop path that includes a first path from the second terminal to the first segment, a second path from first segment to a first point on the antenna ground, a portion of the antenna ground from the first point to a second point, and a third path from the second point to the third terminal. The tuning element may selectively activate the switchable loop path to boost performance of the antenna in a frequency band between 3300 MHz and 5000 MHz when needed.

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 first and second antennas formed from respective first and second segments of a housing. The first antenna may have a first feed coupled to the first segment by a first switch and coupled to the first segment by a first conductive trace. The second antenna may have a second feed coupled to the second segment by a second switch and coupled to the second segment by a second conductive trace. The first segment may be separated from the second segment by a single gap, a data connector may pass through the second segment, and the antennas may selectively cover a low band. Alternatively, the first segment may be separated from the second segment by a third segment and two gaps, the data connector may pass through the third segment, and the first and second antennas may concurrently cover the low band.

Abstract: An electronic device may include first and second antennas formed from respective first and second segments of a housing. The first antenna may have a first feed coupled to the first segment by a first switch and coupled to the first segment by a first conductive trace. The second antenna may have a second feed coupled to the second segment by a second switch and coupled to the second segment by a second conductive trace. The first segment may be separated from the second segment by a single gap, a data connector may pass through the second segment, and the antennas may selectively cover a low band. Alternatively, the first segment may be separated from the second segment by a third segment and two gaps, the data connector may pass through the third segment, and the first and second antennas may concurrently cover the low band.

Abstract: An electronic device may have an antenna module with a triplet of antennas on a substrate. The triplet may include a first antenna with a radiating element formed from a patch on the substrate and second and third antennas having radiating elements formed from patches on that extend across a smaller lateral area than the patch in the first antenna. The patches in the second and third antennas may have extended electrical lengths formed from parasitic patches embedded within the substrate that are coupled to opposing edges of the patches by fences of conductive vias. The antenna module may include phased antenna arrays for conveying centimeter/millimeter wave signals. Signal conductors for the antennas may be distributed across multiple metallization layers of the substrate.

Abstract: An electronic device may have peripheral conductive housing structures, a display frame, a support plate, a logic board, and an antenna. The antenna may have a resonating element that includes a first slot between the logic board and a segment of the peripheral conductive housing structures, a second slot between the display frame and the segment, and optionally a third slot between the between the support plate and the segment. The slots may be at least partially overlapping, may have respective lengths, may be located at respective distances from a cover layer for the display, and may collectively receive radio-frequency signals in a frequency band such as the L5 GPS band. Switching circuitry and filter circuitry may be coupled to the antenna feed and/or to the antenna feed(s) of one or more adjacent antennas in the electronic device to help to isolate the antennas from each other.

Abstract: A communication terminal may include an array of antenna modules. Each module may include an array of radiators on a substrate and a radio-frequency lens overlapping the array. The lens may include a tapered base on the substrate and a curved portion on the tapered base. The tapered base and curved portions may be rotationally symmetric about a central axis of the lens. The curved portion may be hemispherical. The tapered base portion may be conical and may have a first radius at the hemispherical portion and a second radius that is less than the first radius at the substrate. At least one radiator in the array may be located beyond the first radius and within the second radius from the central axis. The lens may be formed from lattice having interleaved layers of dielectric segments separated by gaps to reduce the overall weight of the module.

Abstract: A communication terminal may include control circuitry and an array of antenna modules. Each module may include radiators on a substrate, a lens overlapping the radiators, a transceiver chain, and switching circuitry. The control circuitry may control the switching circuitry to activate a set of one or more radiators in a given module. The control circuitry may control the transceiver chain in that module to convey signals at a selected phase using each of the active radiators. Each of the active radiators may convey the signals over signal beams oriented in different directions by the lens. The control circuitry may adjust the active radiators in each module and may adjust the selected phase for each of the modules to generate a combined signal beam in a desired direction. The combined signal beam may be generated using signals from the active radiators in two or more modules across the array.

Abstract: An electronic device may be provided with antennas for receiving signals in first and second ultra-wideband communications bands. The antennas may include a resonating element formed from conductive traces on a dielectric substrate. The substrate may be mounted to an underlying flexible printed circuit. A fence of conductive vias may extend from the resonating element, through the substrate and the flexible printed circuit, to a ground plane on the flexible printed circuit. The fence may form a return path for the antenna. A shielding ring may be formed on the substrate. Additional fences of vias may couple the shielding ring to the ground plane. If desired, the resonating element may include a patch that is not shorted to the ground plane. The fences of vias, the conductive traces, and the ground plane may form a continuous antenna cavity for the resonating element.

Abstract: An electronic device may be provided with control circuitry and wireless circuitry. The wireless circuitry may include a phased antenna array and a radio-frequency integrated circuit having transmit and receive ports. The array may include a first set of stacked patch antennas coupled to the transmit ports and a second set of stacked patch antennas coupled to the receive ports. The integrated circuit may transmit ranging signals at millimeter wave frequencies using the transmit ports and the first set of antennas. The integrated circuit may receive a reflected version of the transmitted ranging signals that has been reflected off of an external object using the receive ports and the second set of antennas. The control circuitry may identify a distance between the electronic device and the external object based on the transmitted and received signals.

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 be provided with an antenna for receiving signals in first and second ultra-wideband communications bands. The antenna may include a shielding ring that runs around first and second arms. The first arm may radiate in the first band and the second arm may radiate in the second band. The first arm may have an end formed from a first segment of the ring and a radiating edge facing the second arm. The second arm may have an end formed from a second segment of the ring and a radiating edge facing the first arm. First and second sets of conductive vias may couple the ring to ground. The first set may form a return path for the first arm. The second set may form a return path for the second arm.

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 be provided with wireless circuitry that includes first, second, and third antennas used to determine the position and orientation of the electronic device relative to external equipment. The antennas may include patch elements on respective substrates mounted to a flexible printed circuit. Each substrate may include fences of conductive vias that are coupled to ground and that laterally surround the corresponding patch element. Control circuitry may identify phase differences between the first and second antennas and between the second and third antennas and may identify an angle of arrival of received ultra-wideband signals using the phase differences. The control circuitry may compare the phase differences to a set of predetermined surfaces of phase differences to identify environmental loading conditions for the antenna. The control circuitry may correct the angle of arrival using offsets identified based on the environmental loading conditions.

Abstract: An electronic device may be provided with an antenna for receiving signals in first and second ultra-wideband communications bands. The antenna may include a shielding ring that runs around first and second arms. The first arm may radiate in the first band and the second arm may radiate in the second band. The first arm may have an end formed from a first segment of the ring and a radiating edge facing the second arm. The second arm may have an end formed from a second segment of the ring and a radiating edge facing the first arm. First and second sets of conductive vias may couple the ring to ground. The first set may form a return path for the first arm. The second set may form a return path for the second arm.

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.