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 be provided with an antenna having a resonating element formed from a segment of peripheral conductive housing structures. A speaker may be aligned with first openings in the segment. A vent may be aligned with second openings in the segment. A connector may protrude through the segment. A trace combiner for the antenna may be patterned onto the speaker and may be coupled to the segment. Tuners for the antenna may be disposed on first and second flexible printed circuits that extend along opposing sides of the connector. The tuners may be controlled through the speaker. The second flexible printed circuit may extend along the vent. The vent may have a vent cowling with a cut-out region next to the tuner on the second flexible printed circuit.

Abstract: An electronic device may be provided with an antenna having a resonating element formed from a segment of peripheral conductive housing structures. A speaker may be aligned with first openings in the segment. A vent may be aligned with second openings in the segment. A connector may protrude through the segment. A trace combiner for the antenna may be patterned onto the speaker and may be coupled to the segment. Tuners for the antenna may be disposed on first and second flexible printed circuits that extend along opposing sides of the connector. The tuners may be controlled through the speaker. The second flexible printed circuit may extend along the vent. The vent may have a vent cowling with a cut-out region next to the tuner on the second flexible printed circuit.

Abstract: An electronic device may be provided with a flexible printed circuit and a rigid printed circuit mounted to the flexible printed circuit using a board-to-board (B2B) connector. The flexible printed circuit may include signal conductors coupled to one or more antennas on the rigid printed circuit through the B2B connector. A given one of the signal conductors may include a phase shifter segment on the flexible printed circuit and/or a thick impedance matching segment on the rigid printed circuit that help to form a smooth impedance transition from the flexible printed circuit to the rigid printed circuit and the antenna(s). The B2B connector may include signal contacts interleaved with a ground contacts. The B2B connector may include ground bars laterally surrounding the signal and ground contacts to maximize the strength of mechanical coupling between the flexible printed circuit and the rigid printed circuit.

Abstract: An electronic device may be provided with a sensor module and an antenna having an antenna arm, ground structures, and a tuner. The tuner may be mounted to a printed circuit overlapping the sensor module. A spring may be mounted to the printed circuit and may couple the tuner to a conductive chassis of the sensor module. The sensor module may include optical sensors that gather sensor data through a display and may form ground paths from the tuner to the ground structures. Conductive interconnect structures such as springs may exert biasing forces in different directions to couple the ground paths to different layers of the ground structures. This may serve to couple the antenna to the ground structures as close as possible to the tuner, thereby maximizing antenna performance, despite the presence of the sensor module.

Abstract: An electronic device may be provided with an antenna resonating element on a first substrate that is mounted to a second substrate. A signal conductor may be coupled to a feed terminal on the antenna resonating element. The signal conductor may include impedance matching structures for the antenna. The impedance matching structures may include an open transmission line stub, a grounded transmission line stub, and a phase shifting segment. The impedance matching structures may configure the antenna to exhibit a wide bandwidth in an ultra-wideband (UWB) frequency band. If desired, the signal conductor may have a phase-shifting segment configured to match a non-50 Ohm impedance of a radio-frequency front end coupled to the signal conductor.

Abstract: An electronic device may be provided with an antenna having a resonating element and a light source module mounted to a flexible printed circuit and a metal cowling. The module may emit light through a rear housing wall. The printed circuit may be interposed between the metal cowling and a conductive support plate in the rear housing wall. The printed circuit may include a ground trace coupled to the resonating element. A dimpled pad may couple the ground trace to the support plate. Compressive foam may be used to exert a force against the flexible printed circuit that presses the dimpled pad against the conductive support plate. The ground trace and the dimpled pad may form a return path to ground for the resonating element. The dimpled pad may occupy less height within the device than other structures such as metal springs.

Abstract: An electronic device may be provided with a housing and an antenna. The antenna may be on a first substrate mounted to a second substrate. The housing may include a dielectric cover, a conductive plate on the dielectric cover, and a mid-chassis. The second substrate may be mounted to the mid-chassis. The antenna may include a conductive patch extending from a segment of a conductive ring on the first substrate. The conductive plate may have an opening aligned with the conductive patch. The first substrate may be separated from the dielectric cover by an air gap. A conductive gasket may couple the conductive ring to the conductive plate and may laterally surround the air gap and the opening. The antenna may convey ultra-wideband (UWB) signals through the air gap, the opening, and the dielectric cover layer.

Abstract: An electronic device may be provided with peripheral conductive housing structures having first and second segments. A flexible printed circuit may have a first tail that extends along the first and second segments and a second tail that extends along the first segment. A conductive trace on the first tail may be coupled to an antenna feed terminal on the second segment. A conductive trace on the second tail may couple the conductive trace on the first tail to the first segment. A tuner and filters may be disposed on the flexible printed circuit and may be coupled to the conductive traces. The conductive trace on the second tail may have a tapered width. An antenna in the device may have a resonating element that includes both the first and second segments, thereby allowing the antenna to exhibit a wide bandwidth from 1.1-5 GHz.

Abstract: An electronic device may be provided with peripheral conductive housing structures, a first antenna, and a second antenna. A gap may divide the housing structures into a first segment forming an arm of the first antenna and a second segment forming an arm of the second antenna. A first feed terminal may be coupled to the first segment and a second feed terminal may be coupled to the second segment. Switchable components may be coupled in parallel between the first and second feed terminals across the gap. The switchable components may be adjusted to tune the frequency response of the first and/or second antenna. The switchable components may have a first state in which only the first feed terminal feeds the first antenna and may have a second state in which both the first and second feed terminals feed the first antenna.

Abstract: An electronic device may be provided with peripheral conductive housing structures having a first segment and a second segment. First and second antenna feeds may be coupled between the first segment and the ground structures. The first feed may convey signals in a first band and the second feed may convey signals in a second band. The first segment may be near-field coupled to a slot between the second segment and the ground structures. A first tuner may be coupled between the second segment and the ground structures and may adjust a resonance of the first segment in the first and second bands. A second tuner coupled to the first feed may perform impedance matching in the first band and aperture tuning in the second band. A third tuner coupled to the second feed may perform impedance matching in the second band and aperture tuning in the first 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 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: A radio frequency device has a multifunctional tuner that stores measurements of reflection coefficient parameter in a register. The radio frequency device also has a transceiver that has a transmitter. The transceiver may detect a transmitter signal from the transmitter to an antenna in an initial tuning state and then determine whether the transmitter signal is stable. In response to the transmitter signal being stable, the transceiver may measuring the reflection coefficient parameters at the multifunctional tuner. Furthermore, the radio frequency device has a baseband controller that has a memory to store instructions and a processor to execute the instructions. The instructions cause the processor to determine an antenna impedance based on the reflection coefficient parameters, and in response to determining that the antenna impedance is greater than or less than a threshold antenna impedance, iteratively tune the antenna using the multifunctional tuner.

Abstract: An electronic device may be provided with an antenna module. A phased antenna array of dielectric resonator antennas may be disposed within the antenna module. The dielectric resonator antennas may include dielectric columns excited by feed probes. A flexible printed circuit may include transmission lines coupled to the feed probes. The flexible printed circuit may have a first end coupled to the antenna module and extending towards peripheral conductive housing structures forming an additional antenna and a second end coupled to transceiver circuitry. Ground traces on the flexible printed circuit may be shorted to ground structures at the first and second ends to improve the antenna efficiency of the additional antenna. The flexible printed circuit may include an elongated slot with overlapping conductive structures and laterally surrounded by a fence of conductive vias to improve the flexibility of the flexible printed circuit while providing satisfactory antenna performance.

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: An electronic device may be provided with wireless circuitry and a housing with upper and lower ends. The upper end may include first and second inverted-F antennas formed from portions of conductive peripheral housing structures separated from an antenna ground by a slot. The upper end may include an open slot antenna formed from a portion of the slot. The upper end may include an additional inverted-F antenna that overlap the slot. A parasitic element may be disposed between the open slot antenna and the additional inverted-F antenna and coupled to the antenna ground at a proximal end. A tuning component may be coupled between the parasitic element and the antenna ground.