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: An electronic device housing may have a rear housing wall that forms a metal ground plane. A slot may be formed in the metal ground plane. The slot may have one or more open ends along an edge of the ground plane. A near-field communications loop antenna may overlap the slot. The near-field communications loop antenna may have one or more turns. A current path through the metal ground plane may form one of the turns in the near-field communications loop antenna. The slot may form portions of non-near-field-communications antennas in addition to the near-field communications loop antenna. The slot in the non-near-field-communications antennas may be fed using an indirect antenna feed structure. Components such as a capacitor and inductor may help allow non-near-field communications antenna and the near-field communications antenna to be formed from common portions of the metal ground plane.

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 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 include a peripheral conductive wall. A gap in the wall may divide the wall into first and second segments. The device may include a first antenna having a first resonating element arm formed from the first segment and a second antenna having a second resonating element arm formed from the second segment. A non-near-field communications transceiver may perform multiple-input and multiple-output (MIMO) operations using the first and second antennas. The gap may provide satisfactory isolation between the first and second antennas while the first and second antennas perform MIMO operations. Near-field communications circuitry may convey near-field communications signals over a conductive loop path that includes portions of the first and second segments and the antenna ground. The volume of the conductive loop path may extend across substantially all of a width of the electronic device.

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.

Abstract: An electronic device may have wireless circuitry with antennas. An antenna resonating element arm for an antenna may be formed from peripheral conductive structures running along the edges of a device housing. Elongated conductive members may longitudinally divide openings between the peripheral conductive housing structures and the ground. The elongated conductive members may extend from an internal ground to outer ends of the elongated conductive members that are located adjacent to the gaps. Transmission lines may extend along the elongated conductive members to antenna feeds at the outer ends. The elongated conductive members may form open slots that serve as slot antenna resonating elements for the antenna.

Abstract: An electronic device may have a display in a housing with a metal wall. An antenna may have an antenna ground formed from the wall and an antenna resonating element. Transceiver circuitry may be coupled to an antenna feed that extends between the antenna resonating element and the antenna ground. A return path may extend between the antenna resonating element and the antenna ground in parallel with the feed. The antenna resonating element may have segments that are coupled by a frequency dependent filter. At a first frequency, the filter may have a low impedance so that the antenna resonating element has a first effectively length. At a second frequency that is greater than the first frequency, the filter may have a high impedance so that the antenna resonating element has a second effective length that is shorter than the first effective length.

Abstract: An electronic device may have a hybrid antenna that includes a slot resonating element formed from a slot in a ground plane and a planar resonating element formed over the slot. A parasitic element may be disposed over the planar element. A switch may couple the parasitic element to the ground. A tunable circuit may couple the planar element to the ground. The switch and tunable circuit may be placed in different tuning states. In a first state, the tunable circuit and switch form open circuits. In a second state, the tunable circuit may an open circuit and the switch is closed. In a third state, the tunable circuit forms a return path and the switch forms an open circuit. This may allow the antenna to operate with satisfactory efficiency in low, mid, and high bands despite volume constraints imposed on the antenna.

Abstract: An accessory such as a wireless earbud may have an antenna for transmitting and receiving wireless signals. A housing for the earbud may have a main body portion and an extended portion that forms a stalk protruding from the main body portion. The earbud may have a speaker aligned with a speaker port in the main body portion. The antenna may have an elongated shape and may extend along the stalk. The stalk may have a plastic housing wall portion. The antenna may be formed from first and second metal traces on opposing sides of a printed circuit substrate. The first metal trace may form an antenna resonating element arm and may lie between the substrate and the plastic housing wall portion. The second metal trace may be a ground trace. A feed for the antenna may be located at a juncture between the main body portion and the stalk.

Abstract: An electronic device may include a metal housing and a distributed loop antenna. The antenna may include a dielectric carrier. The antenna may include a distributed loop antenna resonating element that extends around the carrier and a loop antenna feed element on the carrier. Portions of the feed element and loop antenna resonating element may be formed from the housing. The feed element may be directly fed and may indirectly feed the distributed loop antenna resonating element via near field electromagnetic coupling. The loop antenna resonating element may include a conductive sheet on the carrier. The conductive sheet and the housing may form a conductive loop path of the loop antenna resonating element. A capacitance may be interposed in the conductive loop path and may be formed by a gap between the conductive sheet and the housing. A speaker driver may be placed within a cavity in the carrier.

Abstract: An electronic device may include a ring-shaped housing member defining an interior volume. The ring-shaped housing member may be configured to receive electronic device components. The ring-shaped housing member may include a first element comprising an angled region, and a second element comprising an angled region. A first intermediate element may be placed between the first and second elements, where the intermediate element is secured to internal surfaces of each of the first and second elements such that the first and second elements do not overlap. The first intermediate element may fasten the first and second elements to one another, and electrically isolate the first and second elements from one another.

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. 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: An electronic device may be provided with wireless communications circuitry and control circuitry. The wireless communications circuitry may include centimeter and millimeter wave transceiver circuitry and a phased antenna array. A dielectric cover may be formed over the phased antenna array. The phased antenna array may transmit and receive antenna signals through the dielectric cover. The dielectric cover may have first and second opposing surfaces. The second surface may face the phased antenna array and may have a curvature. The antenna elements of the phased antenna array may be formed on a dielectric substrate. The dielectric substrate may have one or more thinned regions between antenna elements of the phased antenna array to promote bending. The dielectric substrate may have a smaller thickness in the thinned region than in the regions under the antenna elements. The dielectric substrate may be totally removed in the thinned region.

Abstract: An electronic device may be provided with wireless circuitry. The wireless circuitry may include one or more dual-frequency dual-polarization patch antennas. Each patch antenna may have a patch antenna resonating element that lies in a plane and a ground that lies in a different parallel plane. The patch antenna resonating element may have a first feed located along a first central axis and a second feed located along a second central axis that is perpendicular to the first central axis. The patch antenna resonating element may be rectangular, may be oval, or may have other shapes. A shorting pin may be located at an intersecting point between the first and second axes. The patch antennas may be used in beam steering arrays. The patch antennas may be used for wireless power transfer at microwave frequencies or other frequencies and may be used to support millimeter wave communications.

Abstract: An electronic device may communicate with an external device and may include one or more phased antenna arrays that transmit and receive a beam of millimeter wave signals. Beam steering circuitry may be coupled to the phased antenna array and may be adjusted to steer a direction of the beam. Control circuitry may control the beam steering circuitry to sweep the beam of millimeter wave signals over multiple beam directions. The control circuitry may gather wireless performance data and may compare the wireless performance metric data at each beam direction in the sweep prior to gathering wireless performance metric data at other beam directions in the sweep. The first beam direction in the sweep may be selected based on an initial position of the external device and/or based on sensor data gathered by the control circuitry.

Abstract: An electronic device such as a wireless earbud may have antenna structures that are configured to form one or more antenna portions or antennas for transmitting and receiving wireless signals. The device may include control circuitry that is configured to selectively activate one or more antennas or antenna portions to transmit and receive wireless signals for the device. The device may include sensor circuitry that provide sensor data to the control circuitry. The control circuitry may use the sensor data to select and activate an optimal antenna based on the orientation of the earbud or the environment of the device. The antennas may be formed on opposing sides of a housing for the device. By providing configurable antenna structures, the device may be configured to adapt to the current environment and efficiently perform communications operations.

Abstract: An electronic device may be provided with wireless circuitry. The wireless circuitry may include one or more antennas. The antennas may include cellular telephone antennas, wireless local area network antennas, antenna structures for receiving satellite navigation system signals, and other antennas. An antenna may have an antenna resonating element such as an inverted-F antenna resonating element. The inverted-F antenna resonating element may have an inverted-F antenna resonating element arm formed from metal traces on a flexible printed circuit. The flexible printed circuit may be soldered to an antenna grounding clip. A screw may attach the clip, a speaker tab, a connector bracket, and other metal structures to a metal device housing that serves as ground for the antenna. The screw may be isolated from the antenna grounding clip and the other metal structures by an insulating structure such as an insulating gasket.