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: An electronic device may have tunable antenna structures. A tunable antenna may have an antenna resonating element and an antenna ground. An adjustable electronic component such as an adjustable capacitor, adjustable inductor, or adjustable phase-shift element may be used in tuning the antenna. An impedance matching circuit may be coupled between the tunable antenna and a radio-frequency transceiver. The adjustable electronic component may be coupled to the antenna resonating element or other structures in the antenna or may form part of the impedance matching circuit, a transmission line, a parasitic antenna element, or other antenna structures. During manufacturing, manufacturing variations may cause the performance of the tunable antenna to deviate from desired specifications. Calibration operations may be performed to identify compensating adjustments to be made with the adjustable electronic component.

Abstract: Electronic devices may be provided that contain wireless communications circuitry. The wireless communications circuitry may include radio-frequency transceiver circuitry and antennas. An antenna may be formed from an antenna resonating element arm and an antenna ground. The antenna resonating element arm may have a shorter portion that resonates at higher communications band frequencies and a longer portion that resonates at lower communications band frequencies. A short circuit branch may be coupled between the shorter portion of the antenna resonating element arm and the antenna ground. A series-connected inductor and switch may be coupled between the longer portion of the antenna resonating element arm and the antenna ground. An antenna feed branch may be coupled between the antenna resonating element arm and the antenna ground at a location that is between the short circuit branch and the series-connected inductor and switch.

Abstract: A method of manufacture for a portable computing device is described. In particular, methods and apparatus for assessing a quality of weld joints used to connect one or more components of the portable computing device are described. The weld joints can include one or more weld points. At a weld check station, using a vector network analyzer, a test signal generated can be passed through the weld joint and a response signal can be measured. The measured characteristics can be used to assess a quality of the weld joint. In one embodiment, the vector network analyzer can be used to generate a number of high frequency test signals that are passed through the weld to perform a time domain reflectometry measurement where the weld joint can be accepted or rejected based upon the measurement.

Abstract: A test station may include a test host, a test unit, and a test enclosure. A device under test (DUT) having at least first and second antennas may be placed in the test enclosure during production testing. Radio-frequency test signals may be conveyed from the test unit to the DUT using a test antenna in the test enclosure. In a first time period during which the performance of the first antenna is being tested, the DUT may be oriented in a first position such that path loss between the first antenna and the test antenna is minimized. In a second time period during which the performance of the second antenna is being tested, the DUT may be oriented in a second position such that path loss between the second antenna and the test antenna is minimized. The DUT is marked as a passing DUT if gathered test data is satisfactory.

Abstract: Custom antenna structures may be used to compensate for manufacturing variations in electronic device antennas. An antenna may have an antenna feed and conductive structures such as portions of a peripheral conductive electronic device housing member. The custom antenna structures compensate for manufacturing variations that could potentially lead to undesired variations in antenna performance. The custom antenna structures may make customized alterations to antenna feed structures or conductive paths within an antenna. An antenna may be formed from a conductive housing member that surrounds an electronic device. The custom antenna structures may be formed from a printed circuit board with a customizable trace. The customizable trace may have a contact pad portion on the printed circuit board. The customizable trace may be customized to connect the pad to a desired one of a plurality of contacts associated with the conductive housing member to form a customized antenna feed terminal.

Abstract: Electronic device structures may be tested using a radio-frequency test system. The radio-frequency test system may include radio-frequency test equipment and an associated test fixture. The radio-frequency test equipment may be used in generating and measuring radio-frequency signals. The test fixture may contain adjustable structures that allow the positions of radio-frequency test probes to be adjusted. The test system may be configured to position radio-frequency probes in the test fixture so that some probe contacts form electrical connections with conductive antenna structures. The radio-frequency probes may contain other contacts that are positioned to form electrical connections with conductive electronic device housing structures. During radio-frequency testing, the test equipment in the test system may apply radio-frequency test signals to the device structures under test using the test probes. Corresponding radio-frequency test signals may be measured by the test equipment.

Abstract: Electronic device structures such as structures containing antennas, cables, connectors, welds, electronic device components, conductive housing structures, and other structures can be tested for faults using a test system to perform conducted testing. The test system may include a vector network analyzer or other test unit that generates radio-frequency test signals in a range of frequencies. The radio-frequency test signals may be transmitted to electronic device structures under test using a contact test probe that has at least signal and ground pins. The test probe may receive corresponding radio-frequency signals. The transmitted and received radio-frequency test signals may be analyzed to determine whether the electronic device structures under test contain a fault.

Abstract: Electronic devices may be tested using a test station with a test fixture. The test fixture may include a first holding structure in which a device under test may be placed and a second holding structure for supporting test probes. The second holding structure may be mated with a test probe alignment structure during test station setup operations. The test probe alignment structure may include registration features configured to set the relative position of the first and second holding structures to a known configuration and may include test probe alignment features that can be used to correctly position the placement of the test probes. If at least one of the test probes is not sufficiently aligned to its corresponding alignment feature, the test probe alignment structures will not be able to engage properly with the second holding structure, and the position of the problematic test probe may be adjusted accordingly.

Abstract: Wireless electronic devices may include a transceiver, an antenna resonating element coupled to the transceiver via a transmission line path, transceiver and antenna impedance matching circuits, and other circuitry. The transceiver and the impedance matching circuits may be formed on a first substrate. The antenna resonating element may be formed using a second substrate. The antenna resonating element may be decoupled from the first substrate during testing. First and second sets of test points may be formed at first and second locations long the transmission line path. During testing, a test probe may mate with the first set of test points, whereas an impedance adjustment circuit that serves to electrically isolate the antenna impedance matching circuit from the transceiver may mate with the second set of test points. The impedance adjustment circuit need not be used if the antenna impedance matching circuit is decoupled from the transceiver during testing.

Abstract: Electrical devices may be tested using test equipment. A device may have an associated cable with a connector. The test equipment may have an associated cable with a connector. An adapter may have a pair of connectors. One of the adapter connectors may be connected to the connector of the cable associated with the device and the other of the adapter connectors may be connected to the connector of the cable that is associated with the tester. A retention clip may be attached to a groove in the adapter. Flexible members in the clip may each grasp an opposing side of the adapter within the groove. A retention member in the clip may bear against the connector on the cable that is associated with the device to hold the connectors for the device cable and the adapter together.

Abstract: Electronic device structures such as a conductive housing member that forms part of an antenna may be tested during manufacturing. A test system may be provided that includes a test probe configured to energize the conductive housing member or other conductive structures under test and that includes temporary test structures that may be placed in the vicinity of or in direct contact with the device structures during testing to facilitate detection of manufacturing defects. Test equipment such as a network analyzer may provide radio-frequency test signals in a range of frequencies. An antenna probe may be used to gather corresponding wireless radio-frequency signal data. Forward transfer coefficient data may be computed from the transmitted and received radio-frequency signals. The forward transfer coefficient data or other test data may be compared to reference data to determine whether the device structures contain a fault.

Abstract: Conductive electronic device structures such as a conductive housing member that forms part of an antenna may be tested during manufacturing. A test system may be provided that has a pair of pins or other contacts. Test equipment such as a network analyzer may provide radio-frequency test signals in a range of frequencies. The radio-frequency test signals may be applied to the conductive housing member or other conductive structures under test using the test probe contacts. An antenna may be used to gather corresponding wireless radio-frequency signal data. Forward transfer coefficient data may be computed from the transmitted and received radio-frequency signals. The forward transfer coefficient data or other test data may be compared to reference data to determine whether the conductive electronic device structures contain a fault.

Abstract: Wireless electronic devices may include wireless communications circuitry such as a transceiver, antenna, and other wireless circuitry. The transceiver may be coupled to the antenna through a bidirectional switch connector. The switch connector may mate with a corresponding radio-frequency test probe that is connected to radio-frequency test equipment. When the test probe is mated with the switch connector, the transceiver may be decoupled from the antenna. During transceiver testing, radio-frequency test signals may be conveyed between the test unit and the transceiver using the test probe. During antenna testing, radio-frequency test signals may be conveyed between the test unit and the antenna using the test probe. Transceiver testing and antenna testing may, if desired, be conducted in parallel using the test probe.

Abstract: Conductive electronic device structures such as a conductive housing member that forms part of an antenna may be tested during manufacturing. A test system may be provided that has a capacitive coupling probe. The probe may have electrodes. The electrodes may be formed from patterned metal structures in a dielectric substrate. A test unit may provide radio-frequency test signals in a range of frequencies. The radio-frequency test signals may be applied to the conductive housing member or other conductive structures under test using the electrodes. Complex impedance data, forward transfer coefficient data, or other data may be used to determine whether the structures are faulty. A fixture may be used to hold the capacitive coupling probe in place against the conductive electronic device structures during testing.

Abstract: Electronic device structures such as structures containing antennas, connectors, welds, electronic device components, conductive housing structures, and other structures can be tested for faults using a non-contact test system. The test system may include a vector network analyzer or other test unit that generates radio-frequency tests signals in a range of frequencies. The radio-frequency test signals may be transmitted to electronic device structures under test using an antenna probe that has one or more test antennas. The antenna probe may receive corresponding radio-frequency signals. The transmitted and received radio-frequency test signals may be analyzed to determine whether the electronic device structures under test contain a fault.

Abstract: Wireless electronic devices include wireless communications circuitry such as transceiver circuitry coupled to an antenna resonating element. The transceiver circuitry and the antenna element may be formed on first and second substrates, respectively. In compact wireless devices, transceiver and antenna matching circuits may be formed on the first substrate. During production testing, a radio-frequency test probe with integrated matching circuitry may be used to mate with a corresponding contact point on the first substrate. The integrated matching circuitry may include resistors, capacitors, and inductors soldered in desired series-parallel configurations within the test probe. When the test probe is mated to the contact point on the first substrate, a test unit connected to the test probe may be used to perform radio-frequency measurements to determine whether the transceiver circuitry satisfies design criteria.

Abstract: A portable test chamber with an open top may serve as a field testing apparatus for wireless testing of electronic devices. A wireless device under test may be mounted within a cavity in the test chamber. The cavity may be surrounded by a dielectric lining of anechoic material. A layer of electromagnetic shielding such as metal foil may cover the outer surfaces of the dielectric lining. The chamber may have a box shape with a rectangular opening at its top. Satellite navigation system signals or other wireless signals may be received through the opening at the top of the test chamber during testing. The electromagnetic shielding may reduce the effects of multipath interference during field tests.

Abstract: Electrical devices may be tested using test equipment. A device may have an associated cable with a connector. The test equipment may have an associated cable with a connector. An adapter may have a pair of connectors. One of the adapter connectors may be connected to the connector of the cable associated with the device and the other of the adapter connectors may be connected to the connector of the cable that is associated with the tester. A retention clip may be attached to a groove in the adapter. Flexible members in the clip may each grasp an opposing side of the adapter within the groove. A retention member in the clip may bear against the connector on the cable that is associated with the device to hold the connectors for the device cable and the adapter together.

Abstract: A method of manufacture for a portable computing device is described. In particular, methods and apparatus for assessing a quality of weld joints used to connect one or more components of the portable computing device are described. The weld joints can include one or more weld points. At a weld check station, using a vector network analyzer, a test signal generated can be passed through the weld joint and a response signal can be measured. The measured characteristics can be used to assess a quality of the weld joint. In one embodiment, the vector network analyzer can be used to generate a number of high frequency test signals that are passed through the weld to perform a time domain reflectometry measurement where the weld joint can be accepted or rejected based upon the measurement.