Abstract: An electronic device may include wireless circuitry with antennas. An antenna resonating element arm for an antenna may be formed from conductive housing structures running along the edges of the device. The antenna may have first and second antenna feeds and multiple adjustable components that bridge a slot between the antenna resonating element and an antenna ground. Control circuitry may control the adjustable components and selectively activate one of the first and second feeds at a given time to place the antenna in first, second, or third operating modes. The control circuitry may determine which operating mode to use based on information indicative of the operating environment of the device. By switching between the operating modes, the control circuitry may shift current hot spots across the length of the resonating element arm to ensure satisfactory performance of the antenna in a variety of operating conditions.

Abstract: An electronic device may be provided with wireless circuitry that includes one or more antennas and a transceiver. An integrated circuit may be coupled between the transceiver and the antenna and may include multiple tunable components such that tune the response of the antenna. The control signals may be generated by a tuning controller external to the integrated circuit. Shared control interface circuitry may be formed on the integrated circuit for interfacing between the tuning controller and each of the tunable components on the integrated circuit. The control interface circuitry may include a conductive path and decoupling circuitry that routes the control signals to corresponding control inputs on each of the tunable components. Sharing the control interface circuitry between each tunable component on the integrated circuit may minimize the space required on the integrated circuit for controlling the response of the antenna.

Abstract: An electronic device may be provided with wireless circuitry that includes an antenna. Control circuitry may perform closed loop tuning adjustments on the antenna. For example, the control circuitry may adjust a tunable component to tune the antenna to a first tuning setting. The control circuitry may gather impedance values from the antenna while tuned to the first tuning setting and may process the impedance values to determine whether to tune the antenna to a second tuning setting. If the impedance values lie within a predetermined complex impedance region, the control circuitry may tune the antenna to the second setting. If the impedance values lie outside of the region, the control circuitry may continue to gather impedance values using the first setting. These operations may compensate for detuning of the antenna due to proximity of a user regardless of how the electronic device is held during operation.

Abstract: An electronic device may be provided with a sidewall, a display module separated from the sidewall by a gap, a display cover, a conductive bucket mounted to the display cover within the gap, and a phased antenna array mounted to the bucket for conveying millimeter wave signals through the display cover. The sidewall may form part of an antenna for conveying non-millimeter wave signals. The array may include resonating elements on a substrate. The resonating elements may be fed using feed terminals coupled to alternating sides of the resonating elements. Dielectric layers having a dielectric constant lower than that of the display cover may be provided on a surface of the display cover within the bucket. The array may operate with satisfactory efficiency despite the small amount of available space within the device, electromagnetic interference from the sidewall and the display module, and dielectric loading by the display cover.

Abstract: An electronic device may be provided with wireless circuitry, a conductive housing, and a display. The display may have an active area that displays image data and an inactive area that does not display image data. The active area may completely surround the inactive area at a front face of the device. A speaker port may be aligned with the inactive area and may emit sound through the inactive area. The wireless circuitry may include first and second antenna arrays. The first array may be configured to transmit and receive wireless signals at frequencies between 10 GHz and 300 GHz through the inactive area of the display. The second array may be configured to transmit and receive wireless signals at frequencies between 10 GHz and 300 GHz through a slot in a rear wall of the conductive housing. Control circuitry may perform beam steering using the first and second arrays.

Abstract: An electronic device may include antennas, a ground, and a housing. First and second gaps in the housing may define a segment that forms a resonating element for a first antenna. First, second, third, and fourth antenna feeds may be coupled between the segment and ground. Control circuitry may control adjustable components to place the device in first, second, third, or fourth modes. In the first and second modes, the first and fourth feeds convey signals at the same frequency using a multiple-input and multiple-output scheme while the second and third feeds are inactive. In the third mode, the second feed is active and the first, third, and fourth feeds are inactive. In the fourth mode, the third feed is active and the first, second, and fourth antenna feeds are inactive. Isolating return paths may be coupled between the segment and ground in the first and second modes.

Abstract: An electronic device may include wireless circuitry with antennas. An antenna resonating element arm for an antenna may be formed from conductive housing structures running along the edges of the device. The antenna may have first and second antenna feeds and multiple adjustable components that bridge a slot between the antenna resonating element and an antenna ground. Control circuitry may control the adjustable components and selectively activate one of the first and second feeds at a given time to place the antenna in first, second, or third operating modes. The control circuitry may determine which operating mode to use based on information indicative of the operating environment of the device. By switching between the operating modes, the control circuitry may shift current hot spots across the length of the resonating element arm to ensure satisfactory performance of the antenna in a variety of operating conditions.

Abstract: An electronic device may be provided with wireless circuitry. The wireless circuitry may include antennas. The antennas may include phased antenna arrays for handling millimeter wave signals. Antennas may be located in antenna signal paths. The antenna signal paths may include adjustable components such as adjustable filters, adjustable gain amplifiers, and adjustable phase shifters. Circuitry may be incorporated into an electronic device to facilitate wireless self-testing operations. Wireless self-testing may involve use of one antenna to transmit an over-the-air antenna test signal that is received by another antenna. The circuitry that facilitates the wireless self-testing operations may include couplers, adjustable switches for temporarily shorting antenna signal paths together, mixers for mixing down radio-frequency signals to allow digitization with analog-to-digital converters, and other circuitry for supporting self-testing operations.

Abstract: An electronic device may be provided with a dielectric cover layer, a dielectric substrate, and a phased antenna array on the dielectric substrate for conveying millimeter wave signals through the dielectric cover layer. The array may include conductive traces mounted against the dielectric layer. The conductive traces may form patch elements or parasitic elements for the phased antenna array. The dielectric layer may have a dielectric constant and a thickness selected to form a quarter wave impedance transformer for the array at a wavelength of operation of the array. The substrate may include fences of conductive vias that laterally surround each of the antennas within the array. When configured in this way, signal attenuation, destructive interference, and surface wave generation associated with the presence of the dielectric layer over the phased antenna array may be minimized.

Abstract: An electronic device may be provided with a dielectric cover layer and a conductive layer on the dielectric cover layer. The conductive layer may define an opening. A dielectric spacer may be mounted to the cover layer within the opening. A substrate may be mounted to the spacer. Vertical conductive structures may extend from the conductive layer to the substrate and may laterally surround the spacer. A phased antenna array may be formed on the substrate and aligned with the opening. The cover layer may have a dielectric constant and thickness that are selected to form a quarter wave impedance transformer for the array at a wavelength of operation of the array. The spacer and the conductive structures may exhibit a cavity resonance at the wavelength. The array and the conductive structures may radiate radio-frequency signals at millimeter wave frequencies through the dielectric cover layer.

Abstract: An electronic device may be provided with wireless circuitry. The wireless circuitry may include one or more antennas and transceiver circuitry such as millimeter wave transceiver circuitry. The antennas may be formed from metal traces on printed circuits. A flexible printed circuit may have an area on which the transceiver circuitry is mounted. Protruding portions may extend from the area on which the transceiver circuitry is mounted and may be separated from the area on which the transceiver circuitry is mounted by bends. Antenna resonating elements such as patch antenna resonating elements and dipole resonating elements may be formed on the protruding portions and may be used to transmit and receive millimeter wave antenna signals through dielectric-filled openings in a metal electronic device housing or a dielectric layer such as a display cover layer formed from glass or other dielectric.

Abstract: An electronic device may be provided with wireless circuitry that includes a phased antenna array. The array may include multiple antennas each having multiple antenna feeds for covering different polarizations. Control circuitry may control the wireless circuitry to transmit signals at millimeter or centimeter wave frequencies using a first set of feeds in the array and at least one selected phase. The wireless circuitry may receive the signals transmitted by the first set of feeds using a second set of feeds in the array. The control circuitry may gather phase measurements for the received signals and may compare the phase measurements to the selected phase to generate phase difference values. The control circuitry may perform external object proximity detection operations based on the phase difference values. The control circuitry may control the wireless circuitry to cycle through different combinations of antenna feeds for the first and second sets.

Abstract: An electronic device may be provided with a sidewall, a display module separated from the sidewall by a gap a display cover, a conductive bucket mounted to the display cover within the gap, and a phased antenna array mounted to the bucket for conveying millimeter wave signals through the display cover. The sidewall may form part of an antenna for conveying non-millimeter wave signals. The array may include resonating elements on a substrate. The resonating elements may be fed using feed terminals coupled to alternating sides of the resonating elements. Dielectric layers having a dielectric constant lower than that of the display cover may be provided on a surface of the display cover within the bucket. The array may operate with satisfactory efficiency despite the small amount of available space within the device, electromagnetic interference from the sidewall and the display module, and dielectric loading by the display cover.

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 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: Electronic devices may be provided that contain wireless communications circuitry. The wireless communications circuitry may include radio-frequency transceiver circuitry and antenna structures. The antenna structures may form a dual arm inverted-F antenna. The antenna may have a resonating element formed from portions of a peripheral conductive electronic device housing member 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. An antenna feed may be coupled across the gap in parallel with the short circuit path. Low band tuning may be provided using an adjustable inductor that bridges the gap. The antenna may have a slot-based parasitic antenna resonating element with a slot formed between portions of the peripheral conductive electronic device housing member and the antenna ground. An adjustable capacitor may bridge the slot to provide high band tuning.

Abstract: An electronic device may be provided with wireless circuitry. The wireless circuitry may include one or more antennas. The antennas may include millimeter wave antenna arrays. Non-millimeter-wave antennas such as cellular telephone antennas may have conductive structures separated by a dielectric gap. In a device with a metal housing, a plastic-filled slot may form the dielectric gap. The conductive structures may be slot antenna structures, inverted-F antenna structures such as an inverted-F antenna resonating element and a ground, or other antenna structures. The plastic-filled slot may serve as a millimeter wave antenna window. A millimeter wave antenna array may be mounted in alignment with the millimeter wave antenna window to transmit and receive signals through the window. Millimeter wave antenna windows may also be formed from air-filled openings in a metal housing such as audio port openings.

Abstract: An electronic device may be provided with wireless circuitry. The wireless circuitry may include one or more antennas. The antennas may include millimeter wave antenna arrays formed from arrays of patch antennas, dipole antennas or other millimeter wave antennas on millimeter wave antenna array substrates. Circuitry such as upconverter and downconverter circuitry may be mounted on the substrates. The upconverter and downconverter may be coupled to wireless communications circuitry such as a baseband processor circuit using an intermediate frequency signal path. The electronic device may have opposing front and rear faces. A display may cover the front face. A rear housing wall may cover the rear face. A metal midplate may be interposed between the display and rear housing wall. Millimeter wave antenna arrays may transmit and receive antenna signals through the rear housing wall.

Abstract: An electronic device may be provided with wireless circuitry. The wireless circuitry may include one or more antennas and transceiver circuitry such as millimeter wave transceiver circuitry. The antennas may be formed from metal traces on a printed circuit. The printed circuit may be a stacked printed circuit including multiple stacked substrates. Metal traces may form an array of patch antennas, Yagi antennas, and other antennas. Antenna signals associated with the antennas may pass through an inactive area in a display and through a dielectric-filled slot in a metal housing for the electronic device. Waveguide structures may be used to guide antenna signals within interior portions of the electronic device.

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.