Abstract: An electronic device may be provided with wireless circuitry and control circuitry. The wireless circuitry may include an antenna with an inverted-F antenna resonating element formed from portions of a peripheral conductive electronic device housing structure and may have an antenna ground that is separated from the antenna resonating element by a gap. The antenna may include a first adjustable component coupled between the antenna resonating element arm and the antenna ground on a first side of the antenna feed and a second adjustable component coupled between the antenna resonating element arm and the antenna ground on a second side of the antenna feed. Control circuitry in the electronic device may adjust the first and second adjustable components between a first tuning mode, a second tuning mode, and a third tuning mode.

Abstract: An electronic device may be provided with wireless circuitry. The wireless circuitry may include antenna structures such as an antenna resonating element arm and an antenna ground. A split return path may be coupled between the antenna resonating element arm and the antenna ground. The antenna structures may form one or more inverted-F antennas when operated at non-near-field communications frequencies. The antenna structures may be coupled to near-field communications transceiver circuitry using a conductive path. When operated at near-field communications frequencies, near-field communications signals may be conveyed using the conductive path, the antenna resonating element arm, the return path, and the antenna ground. A capacitor may be coupled between the conductive path and an antenna ground. The capacitor may short non-near-field communications signals to the antenna ground and block near-field communications signals from passing from the conductive path to the antenna ground.

Abstract: Antenna structures at a given end of an electronic device may include antenna structures that are shared between multiple antennas. The device may include an antenna with an inverted-F antenna resonating element formed from portions of a peripheral conductive electronic device housing structure and may have an antenna ground that is separated from the antenna resonating element by a gap. A short circuit path may bridge the gap. The short circuit path may be a split return path coupled between a first point on the inverted-F antenna resonating element arm and second and third points on the antenna ground. The electronic device may include an additional antenna that includes the antenna ground and metal traces that form an antenna resonating element arm. The antenna resonating element arm of the additional antenna may be parasitically coupled to the inverted-F antenna resonating element and a portion of the split return path.

Abstract: An electronic device may be provided with wireless circuitry and control circuitry. The wireless circuitry may include multiple antennas and transceiver circuitry. An antenna in the electronic device may have an inverted-F antenna resonating element formed from portions of a peripheral conductive electronic device housing structure and may have an antenna ground that is separated from the antenna resonating element by a gap. A split return path may bridge the gap. The split return path may be coupled between a first point on the inverted-F antenna resonating element arm and second and third points on the antenna ground. The split return path may include a first inductor coupled between the first and second points and a second inductor coupled between the first and third points. The first and second inductors may be adjustable.

Abstract: An electronic device may be provided with wireless circuitry. The wireless circuitry may include multiple antennas and transceiver circuitry. The antenna structures at a first end of the electronic device may include an inverted-F antenna resonating element for a first antenna formed from portions of a peripheral conductive electronic device housing structure and an antenna ground that is separated from the antenna resonating element by a gap. The inverted-F antenna resonating element arm may have a first end adjacent a first dielectric-filled gap and an opposing second end adjacent a second dielectric-filled gap. A second antenna may include an additional antenna resonating element arm and the antenna ground. A second end of the additional antenna resonating element arm may be interposed between the first dielectric-filled gap and a first end of the additional antenna resonating element arm. This type of arrangement may ensure the first and second antennas are isolated.

Abstract: An electronic device may be provided with antenna structures and control circuitry. The antenna structures may include an antenna resonating element arm, an antenna ground, and an antenna feed coupled between the antenna resonating element arm and the antenna ground. The electronic device may include a tunable component configured to tune a frequency response of the antenna structures. The electronic device may also include a substrate, a radio-frequency transceiver on the substrate, control circuitry configured to generate control signals, a flexible printed circuit, and a connector. The connector may mechanically secure the flexible printed circuit to the substrate and may be electrically coupled to the transceiver and the control circuitry. The flexible printed circuit may include a radio-frequency transmission line coupled between the antenna feed and the connector and a control signal path coupled between the tunable component and the connector.

Abstract: An electronic device may be provided with wireless circuitry. The wireless circuitry may include multiple antennas and transceiver circuitry. The antennas may include antenna structures at opposing first and second ends of the electronic device. The antenna structures at a given end of the device may include antenna structures that are shared between multiple antennas. The electronic device may include a first antenna with an inverted-F antenna resonating element formed from portions of a peripheral conductive housing structure and may have an antenna ground that is separated from the antenna resonating element by a gap. A return path may bridge the gap. The electronic device may also include a second antenna that includes the antenna ground and an additional antenna resonating element. The antenna resonating element of the second antenna may be parasitically coupled to the return path of the inverted-F antenna at given frequencies.

Abstract: An electronic device may be provided with wireless circuitry and control circuitry. The wireless circuitry may include multiple antennas and transceiver circuitry. An antenna in the electronic device may have an inverted-F antenna resonating element formed from portions of a peripheral conductive electronic device housing structure and may have an antenna ground that is separated from the antenna resonating element by a gap. The antenna ground for the antenna may include a conductive frame for the display. The conductive frame may have a first portion that is separated from the antenna resonating element arm by a first distance and a second portion that is that is separated from the antenna resonating element arm by a second distance that is less than the first distance. The second portion may be configured to form a distributed impedance matching capacitance with the antenna resonating element arm.

Abstract: An electronic device may be provided with wireless circuitry. The wireless circuitry may include multiple antennas and transceiver circuitry. An antenna may have an antenna resonating element formed from portions of a peripheral conductive electronic device housing structure and may have an antenna ground that is separated from the antenna resonating element by a gap. The antenna ground for the antenna may include a first conductive structure that is separated from the antenna resonating element by a first distance and a second conductive structure that is electrically connected to the first conductive structure and separated from the antenna resonating element by a second distance that is less than the first distance. A distributed impedance matching capacitor for the antenna may be formed from the second conductive structure and the antenna resonating element arm. The second conductive structure may be a conductive frame for an electronic component such as a sensor.

Abstract: A compound having the following structure (I): or a pharmaceutically acceptable salt, prodrug, stereoisomer or tautomer thereof, is provided. Related compounds, methods for preparation of the same and uses of the compounds for treatment of various indications, including treatment of necrotic cell diseases and/or inflammation, are also provided.

Abstract: An electronic device may be provided with wireless circuitry and control circuitry. The wireless circuitry may include multiple antennas and transceiver circuitry. An antenna in the electronic device may have an inverted-F antenna resonating element formed from portions of a peripheral conductive electronic device housing structure and may have an antenna ground that is separated from the antenna resonating element by a gap. The antenna may also include an indirectly-fed antenna resonating element that is indirectly fed by a harmonic mode of the inverted-F antenna resonating element via near field electromagnetic coupling. The indirectly-fed antenna resonating element may be a slot. The antenna ground may define at least three edges of the slot and the slot may be aligned with a dielectric-filled gap in the peripheral conductive housing structures. An adjustable circuit may be coupled across the slot to tune the indirectly-fed antenna resonating element.

Abstract: An electronic device may include an antenna having a resonating element, an antenna ground, and a feed. First and second tunable components may be coupled to the resonating element. Adjustable matching circuitry may be coupled to the feed. Control circuitry may use the first tunable component to tune a midband antenna resonance when sensor circuitry identifies that the device is being held in a right hand and may use the second tunable component to tune the midband resonance when the sensor circuitry identifies that the device is being held in a left hand. For tuning a low band resonance, the control circuitry may place the antenna in different tuning states by sequentially adjusting a selected one of the matching circuitry and the tunable components, potentially reverting to a previous tuning state at each step in the sequence. This may ensure that antenna efficiency is satisfactory regardless of antenna loading conditions.

Abstract: A compound having the following structure (I): or a pharmaceutically acceptable salt, prodrug, stereoisomer or tautomer thereof, is provided. Related compounds, methods for preparation of the same and uses of the compounds for treatment of various indications, including treatment of necrotic cell diseases and/or inflammation, are also provided.

Abstract: Electronic device antenna structures may include first and second antennas. A housing may have a periphery that is surrounded by peripheral conductive structures such as a segmented peripheral metal member. A segment of the peripheral metal member may be separated from a ground by an opening. An antenna feed for the first antenna may have a positive antenna terminal coupled to the peripheral metal member and a ground terminal coupled to the ground. A return path for the first antenna may span the opening in parallel with the antenna feed. A plastic carrier may be mounted to a printed circuit and a metal housing structure using screws. The plastic carrier may support an antenna resonating element for the second antenna and may support the return path for the first antenna. The screws may short metal structures on the plastic carrier to the metal structures and traces on the printed circuit.

Abstract: An electronic device may be provided with wireless circuitry. Control circuitry may be used to adjust the wireless circuitry. The wireless circuitry may include an antenna that is tuned using tunable components. The control circuitry may gather information on the current operating mode of the electronic device, sensor data from a proximity sensor, accelerometer, microphone, and other sensors, antenna impedance information for the antenna, and information on the use of connectors in the electronic device. Based on this gathered data, the control circuitry can adjust the tunable components to compensate for antenna detuning due to loading from nearby external objects, may adjust transmit power levels, and may make other wireless circuit adjustments.

Abstract: Electronic devices are provided that contain wireless communications circuitry. The wireless communications circuitry may include radio-frequency transceiver circuitry and antenna structures. An inverted-F antenna may have first and second short circuit legs and a feed leg. The first and second short circuit legs and the feed leg may be connected to a folded antenna resonating element arm. The antenna resonating element arm and the first short circuit leg may be formed from portions of a conductive electronic device bezel. The folded antenna resonating element arm may have a bend. The bezel may have a gap that is located at the bend. Part of the folded resonating element arm may be formed from a conductive trace on a dielectric member. A spring may be used in connecting the conductive trace to the electronic device bezel portion of the antenna resonating element arm.

Abstract: An electronic device may be provided with an antenna. The antenna may have an antenna resonating element and an antenna ground. The antenna resonating element may be formed from peripheral conductive housing structures. An audio jack or other connector may be mounted in an opening in the peripheral conductive housing structures. The audio jack may overlap the antenna ground. Contacts in the audio jack may be coupled to an interference mitigation circuit. The interference mitigation circuit may include capacitors coupled to the ground and inductors coupled between the contacts and the capacitors. Radio-frequency signal blocking inductors may be coupled between the interference mitigation circuit and respective ports in an audio circuit.

Abstract: Electronic devices may include radio-frequency transceiver circuitry and antenna structures. The antenna structures may form a dual arm inverted-F antenna and a monopole antenna sharing a common antenna ground. The antenna structures may have three ports. A first antenna port may be coupled to an inverted-F antenna resonating element at a first location and a second antenna port may be coupled to the inverted-F antenna resonating element at a second location. A third antenna port may be coupled to the monopole antenna. Tunable circuitry can be used to tune the antenna structures. An adjustable capacitor may be coupled to the first port to tune the inverted-F antenna. An additional adjustable capacitor may be coupled to the third port to tune the monopole antenna. Transceiver circuitry for supporting wireless local area network communications, satellite navigation system communications, and cellular communications may be coupled to the first, second, and third antenna ports.

Abstract: An electronic device may have wireless circuitry with antennas. An antenna may have an inverted-F antenna resonating element, an antenna ground, and other resonating element structures. A tip of the antenna resonating element and the antenna ground may be separated by a peripheral housing gap filled with plastic. The antenna may be sensitive to capacitance changes induced by the presence of a user's hand overlapping the gap or other portions of the antenna. A hand capacitance sensing electrode may be mounted in the plastic of the gap or elsewhere in the vicinity of the antenna. A transmission line may couple the hand capacitance sensing electrode to the antenna to retune the antenna in the event that the user's hand overlaps the antenna.

Abstract: An electronic device may be provided with an antenna. The antenna may have an antenna resonating element and an antenna ground. An adjustable inductor may be coupled between the antenna resonating element and the antenna ground. An antenna feed may have a positive feed terminal coupled to the antenna resonating element and a ground antenna feed coupled to the antenna ground. The adjustable inductor may have first and second inductors coupled to respective first and second ports of a switch. The switch may have a third port coupled to the antenna ground. A capacitor may have a first terminal coupled to ground and a second terminal coupled to the first inductor at the first port of the switch. An inductor may be coupled between the antenna resonating element and antenna ground at a location between the adjustable inductor and the antenna feed.