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 an antenna having first and second feeds at different locations. The transceiver circuit may have a first circuit that handles communications using the first feed and may have a second circuit that handles communications using the second feed. A first filter may be interposed between the first feed and the first circuit and a second filter may be interposed between the second feed and the second circuit. The first and second filters and the antenna may be configured so that the first circuit can use the first feed without being adversely affected by the presence of the second feed and so that the second circuit can use the second feed without being adversely affected by the presence of the first feed.

Abstract: Electronic devices may be provided that contain wireless communications circuitry. The wireless communications circuitry may include antenna structures that are formed from an internal ground plane and a peripheral conductive housing member. A conductive path may be formed that connects the peripheral conductive housing member and the internal ground plane. The conductive path may include a flex circuit. A metal structure may be welded to the peripheral conductive housing member. A solder pad and other traces in the flex circuit may be soldered to the metal structure at one end of the conductive path. At the other end of the conductive path, the flex circuit may be attached to the ground plane using a bracket, screw, and screw boss.

Abstract: A wireless electronic device may serve as a device under test in a test system. The test system may include an array of over-the-air antennas that can be used in performing over-the-air wireless tests on the device under test (DUT). A channel model may be used in modeling a multiple-input-multiple-output (MIMO) channel between a multi-antenna wireless base station and a multi-antenna DUT. The test system may be configured to perform over-the-air tests that emulate the channel model. A design and analysis tool may be used to identify an optimum over-the-air test system setup. The tool may be used in converting a geometric model to a stochastic model for performing conducted tests. The tool may be used in converting a stochastic model to a geometric model and then further convert the geometric model to an over-the-air emulated stochastic model. The over-the-air emulated stochastic model may be used in performing conducted tests.

Abstract: An electronic device such as a portable electronic device has wireless communications circuitry. Antennas in the electronic device may be used in transmitting radio-frequency antenna signals. A coupler and antenna signal phase and magnitude measurement circuitry may be used to determine when external objects are in the vicinity of the antenna by making antenna impedance measurements. In-band and out-of-band phase and magnitude signal measurements may be made in determining whether external objects are present. Additional sensors such as motion sensors, light and heat sensors, acoustic and electrical sensors may produce data that can be combined with the proximity data gathered using the antenna-based proximity sensor. In response to detecting that an external object such as a user's body is within a given distance of the antenna, the electronic device may reduce transmit powers, switch antennas, steer a phased antenna array, switch communications protocols, or take other actions.

Abstract: An electronic device such as a portable electronic device has wireless communications circuitry. Antennas in the electronic device may be used in transmitting radio-frequency antenna signals. A coupler and antenna signal phase and magnitude measurement circuitry may be used to determine when external objects are in the vicinity of the antenna by making antenna impedance measurements. In-band and out-of-band phase and magnitude signal measurements may be made in determining whether external objects are present. Additional sensors such as motion sensors, light and heat sensors, acoustic and electrical sensors may produce data that can be combined with the proximity data gathered using the antenna-based proximity sensor. In response to detecting that an external object such as a user's body is within a given distance of the antenna, the electronic device may reduce transmit powers, switch antennas, steer a phased antenna array, switch communications protocols, or take other actions.

Abstract: An antenna resonating element may be mounted in an antenna cavity. The antenna resonating element may have a printed circuit board substrate with a patterned metal layer. Components may be soldered to the antenna resonating element using solder with a given melting point before soldering the antenna resonating element the antenna cavity using solder with a lower melting point. Solder widow openings may be formed in the antenna resonating element and antenna cavity to allow for application of solder paste. Engagement features and alignment structures may be used to align the antenna resonating element relative to the antenna cavity. The antenna cavity may have a curved opening. The printed circuit board substrate may be bent to the shape of the curved opening before soldering components to the printed circuit board. An elastomeric fixture may be used to hold the antenna resonating element to the cavity during soldering.

Abstract: Electronic devices are provided that contain wireless communications circuitry. The wireless communications circuitry may include radio-frequency transceiver circuitry and antenna structures. The antenna structures may include antennas such as inverted-F antennas that contain antenna resonating elements and antenna ground elements. Antenna resonating elements may be formed from patterned conductive traces on substrates such as flex circuit substrates. Antenna ground elements may be formed from conductive device structures such as metal housing walls. Support and biasing structures such as dielectric support members and layer of foam may be used to support and bias antenna resonating elements against planar device structures. The planar device structures against which the antenna resonating elements are biased may be planar dielectric members such as transparent layers of display cover glass or other planar structures.

Abstract: Electronic devices may be provided that contain wireless communications circuitry. The wireless communications circuitry may include antenna structures that are formed from an internal ground plane and a peripheral conductive housing member. A conductive path may be formed that connects the peripheral conductive housing member and the internal ground plane. The conductive path may include a flex circuit. The flex circuit can include a solder flow barrier to constrain flow of solder. A metal structure may be welded to the peripheral conductive housing member. A solder pad and other traces in the flex circuit may be soldered to the metal structure at one end of the conductive path. At the other end of the conductive path, the flex circuit may be attached to the ground plane using a bracket, screw, and screw boss.

Abstract: A test system may include test stations for testing the radio-frequency performance of wireless electronic devices. A reference test station may perform test measurements on a group of wireless electronic devices under test (DUTs) to select a reference DUT. The reference test station may gather radio-frequency measurements at a number of test frequencies from the group of DUTs. The reference test station may compute statistical data associated with the gathered measurements. The reference test station may compute weight values associated with each test frequency based on the statistical parameters. The reference test station may compute a weighted mean square error value for each DUT based on the weight values and the statistical data. The reference test station may select a DUT having a minimum weighted mean square error value to serve as the reference DUT, which may be used to calibrate test stations in the test system.

Abstract: A test system may include a wireless test chamber with metal walls lined with pyramidal absorbers. A trapdoor may be provided in a wall opening to accommodate a robotic arm. The robotic arm may have grippers that grip a device under test or a support structure that is supporting a device under test. The robotic arm may move the device under test to a docking station for automatic battery charging during testing. When it is desired to perform wireless tests on a device under test, the robotic arm may move the device under test through the trapdoor into an interior portion of the test chamber. A turntable and movable test antenna may be used to rotate the device under test while varying angular orientations between test antenna and device under test. Emitted radiation levels can be measured using a liquid filled phantom and test probe on a robotic arm.

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 include conductive housing structures such as a peripheral conductive housing member. The antenna structures may be based on an inverted-F antenna resonating element or other types of antenna resonating element. An electronic device may have near field communications circuitry and non-near-field communications circuitry such as cellular telephone, satellite navigation system, or wireless local area network transceiver circuitry. Antenna structures may be configured to handle signals associated with the non-near-field communications circuitry. The antenna structures may also have portions that form a near field communications loop antenna for handling signals associated with the near field communications circuitry.

Abstract: A handheld electronic device may be provided that contains a conductive housing and other conductive elements. The conductive elements may form an antenna ground plane. One or more antennas for the handheld electronic device may be formed from the ground plane and one or more associated antenna resonating elements. Transceiver circuitry may be connected to the resonating elements by transmission lines such as coaxial cables. Ferrules may be crimped to the coaxial cables. A bracket with extending members may be crimped over the ferrules to ground the coaxial cables to the housing and other conductive elements in the ground plane. The ground plane may contain an antenna slot. A dock connector and flex circuit may overlap the slot in a way that does not affect the resonant frequency of the slot. Electrical components may be isolated from the antenna using isolation elements such as inductors and resistors.

Abstract: An electronic device may have a housing such as a metal housing. A display may be mounted in the metal housing. Antenna structures may be mounted in the housing under an inactive peripheral portion of the display. Integrated circuits and other electrical components may be mounted in the housing under an active central portion of the display. Shielding structures may be configured to form a wall that extends between the display and the metal housing. The shielding structures may include a sheet of conductive fabric that is shorted to the metal housing and metal chassis structures in the display. The shielding structures may also include a tube of conductive fabric that is capacitively coupled to ground traces in a touch sensor panel. The conductive fabric tube and the sheet of conductive fabric may be shorted to each other using conductive adhesive.

Abstract: An electronic device may have a conductive housing with an antenna window. Antenna structures may be mounted adjacent to the antenna window. The antenna structures may have a dielectric carrier. Patterned metal antenna traces may be formed on the surface of the dielectric carrier. A proximity sensor may be formed from a flexible printed circuit mounted on the dielectric carrier. The flexible printed circuit may have a tail that contains a transmission line for feeding the antenna structures. The transmission line may include a positive signal conductor that is maintained at a desired distance from the conductive housing using a polymer sheet. A portion of the antenna structures may protrude between a microphone and a camera module. Plastic camera module housing structures may have an inner surface coated with a shielding metal. A U-shaped conductive fabric layer may be used as a grounding structure.

Abstract: Antenna structures for an antenna may be formed from a dielectric carrier with metal structures. The metal structures may be patterned to cover all sides of the dielectric carrier. The dielectric carrier may have a shape with six sides or other shape that creates a three-dimensional layout for the antenna structures. The antenna structures may have a tunable circuit that allows the antenna to be tuned. The tunable circuit may have first and second terminals coupled to one of the sides of the carrier. The metal structures may be configured to form an inverted-F antenna resonating element. Portions of the metal structures may form a first arm for an inverted-F antenna and portions of the metal structures may form a second arm for the inverted-F antenna. The antenna may operate in multiple communications bands. The tunable circuit may tune one band without significantly tuning other bands.

Abstract: An electronic device may have a housing in which an antenna and a proximity sensor formed from flex circuit structures are mounted. The flex circuit structures may include first and second flex circuit layers. The first and second flex circuit layers may include metal antenna structures and metal proximity sensor electrode structures. Solder may be used to attach electrical components to the flex circuit layers and may be used to electrically connect metal structures on the first and second flex circuit layers to each other. The first and second flex circuit layers may be laminated together using a compressive fixture. The compressive fixture may have a first fixture with a convex surface and a second fixture with a concave surface so that the laminated flex circuit layers are provided with a bend.

Abstract: An electronic device may be provided with antenna structures. The antenna structures may be formed using a dielectric carrier structure such as a speaker enclosure, so that interior space within the electronic device that is occupied by a speaker can be used in forming an antenna. A speaker driver may be mounted in the speaker enclosure. Openings in the speaker enclosure may allow sound from the speaker driver to be emitted from the speaker enclosure. The antenna structures may have first and second loop antenna resonating elements. The first loop antenna resonating element may indirectly feed the second loop antenna resonating element. The second loop antenna resonating element may be a distributed loop element formed from a strip of metal with a width that loops around the speaker enclosure. Openings in the second loop antenna resonating element may be aligned with the speaker enclosure openings.

Abstract: An electronic device may be provided with antenna structures. The antenna structures may be formed using a dielectric carrier structure. The antenna structures may have first and second loop antenna resonating elements. The first loop antenna resonating element may indirectly feed the second loop antenna resonating element. The second loop antenna resonating element may be a distributed loop element formed from multiple antenna resonating element subloops. The second loop antenna resonating element may be formed from a strip of metal with a width that loops around the dielectric carrier. An opening in the metal may separate first and second subloop antenna resonating elements from each other in the second loop antenna resonating element. Openings in the metal may form metal segments that collectively form an inductance for the first subloop. Antenna currents may flow through metal traces on the carrier and portions of an electronic device housing wall.

Abstract: Radio frequency test systems for characterizing antenna performance in various radio coexistence scenarios are provided. In one suitable arrangement, a test system may be used to perform passive radio coexistence characterization. During passive radio coexistence characterization, at least one signal generator may be used to feed aggressor signals directly to antennas within an electronic device under test (DUT). The aggressor signals may generate undesired interference signals in a victim frequency band, which can then be received and analyzed using a spectrum analyzer. During active radio coexistence characterization, at least one radio communications emulator may be used to communicate with a DUT via a first test antenna. While the DUT is communicating with the at least one radio communications emulator, test signals may also be conveyed between DUT 10 and a second test antenna. Test signals conveyed through the second test antenna may be used in obtaining signal interference level measurements.

Abstract: A handheld electronic device may be provided that contains a conductive housing and other conductive elements. The conductive elements may form an antenna ground plane. One or more antennas for the handheld electronic device may be formed from the ground plane and one or more associated antenna resonating elements. Transceiver circuitry may be connected to the resonating elements by transmission lines such as coaxial cables. Ferrules may be crimped to the coaxial cables. A bracket with extending members may be crimped over the ferrules to ground the coaxial cables to the housing and other conductive elements in the ground plane. The ground plane may contain an antenna slot. A dock connector and flex circuit may overlap the slot in a way that does not affect the resonant frequency of the slot. Electrical components may be isolated from the antenna using isolation elements such as inductors and resistors.