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: The present invention relates to a new process for preparing polyisocyanates containing isocyanurate groups and being flocculation-stable in solvents from (cyclo)aliphatic diisocyanates.

Abstract: Allocation of buffers for a TCP proxy session between a client and a server by a service gateway includes monitoring dynamic network behaviors for server and client side sessions of the TCP proxy session; and allocating capacity for a server side buffer and capacity for a client side buffer in a memory buffer based on the dynamic server side network behaviors, the dynamic client side network behaviors, and a weighted average of a capacity of the memory buffer. In one approach to the allocation, the gateway determines whether an available capacity of the server or client side buffer is sufficient to store a data packet. If not sufficient, the allocated capacity of the server or client side buffer is increased based on measurements of the dynamic network behaviors and the weighted average, and the available capacity of the server or client side buffer is adjusted accordingly.

Abstract: An electronic device may have control circuitry that uses a reflectometer to measure antenna impedance during operation. The reflectometer may have a directional coupler that is coupled between radio-frequency transceiver circuitry and an antenna. A calibration circuit may be coupled between the directional coupler and the antenna. The calibration circuit may have a first port coupled to the antenna, a second port coupled to the directional coupler, and a third port that is coupled to a calibration resistance. The reflectometer may have terminations of identical impedance that are coupled to ground. Switching circuitry in the reflectometer may be used to route signals from the directional coupler to a feedback receiver for measurement by the control circuitry or to ground through the terminations. Calibrated antenna reflection coefficient measurements may be used in dynamically adjusting the antenna.

Abstract: An electronic device may have wireless circuitry with antennas. An antenna resonating element arm for a given antenna may be formed from metal structures supported by a plastic carrier. The antenna resonating element arm may be coupled to switching circuitry to isolate the antenna resonating element arm when the antenna resonating element arm is not being used to handle communications in a communications band. The electronic device may have a metal housing. A slot may separate a peripheral portion of the housing such as a sidewall portion from a planar rear portion. The sidewall portion and the planar rear portion may form an additional antenna that operates at communications frequencies outside of the communications band handled by the given antenna. A parasitic antenna resonating element arm may be formed in the slot to enhance the frequency response of the additional antenna.

Abstract: An electronic device may have wireless circuitry with antennas. An antenna resonating element arm for an antenna may be formed from conductive housing structures running along the edges of a device. The antenna may have a pair of switchable return paths that bridge a slot between the antenna resonating element and an antenna ground. An adjustable component and a feed may be coupled in parallel across the slot. The adjustable component may switch a capacitor into use or out of use and the return paths may be selectively opened and closed to compensate for antenna loading due to the presence of external objects near the electronic device.

Abstract: Reducing buffer usage for a TCP proxy session between a client and a server by a service gateway includes: determining a first round trip time (RTT) for a server side TCP session and determining a second RTT for a client side TCP session; comparing the first RTT with the second RTT; determining whether the second RTT exceeds the first RTT beyond a threshold; if so, then calculating a desired RTT based on the second RTT; and setting a timer according to the calculated desired RTT, where a TCP acknowledgement for the server side TCP session is delayed until the timer expires. The desired RTT may be calculated as a percentage of the second RTT or as the second RTT minus a predetermined value. The service gateway waits until the timer has expired before sending a TCP acknowledgement data packet to the server.

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.

Abstract: An electronic device may be provided with wireless circuitry. The wireless circuitry may include wireless transceiver circuitry that transmits signals towards an antenna. A signal path may carry the transmitted signals to the antenna. Reflected signals from the antenna may be carried along the signal path towards the transceiver circuitry. Coupler circuitry may include a forward coupler that taps the transmitted signals, a first reverse coupler that taps the reflected signals from the antenna, and a second reverse coupler that taps the reflected signals that have passed through the first reverse coupler. Analog processing circuitry and digital processing circuitry may be used to produce an impedance measurement from the tapped signals from the coupler circuitry. The analog processing circuitry may include analog signal mixers, low pass filters, and analog-to-digital converter circuitry.

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 that are separated from a round by an elongated opening. The electronic device may have a central longitudinal axis that divides the antenna resonating element arm and other antenna structures into symmetrical halves that exhibit mirror symmetry with respect to the central longitudinal axis. The antenna structures may include symmetrical slot antenna resonating elements on opposing sides of the central longitudinal axis. Electrical components such as switches and antenna tuning inductors may be coupled to the antenna structures in a configuration that is symmetrical with respect to the central longitudinal axis. The electrical components may be used to place the antenna structures in an unflipped configuration or in a symmetrical flipped configuration.

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 antennas that are tuned, adjustable impedance matching circuitry, antenna port selection circuitry, and adjustable transceiver circuitry. Wireless circuit adjustments may be made by ascertaining a current usage scenario for the electronic device based on sensor data, information from cellular base station equipment or other external equipment, signal-to-noise ratio information or other signal information, antenna impedance measurements, and other information about the operation of the electronic device.

Abstract: An electronic device may be provided with wireless circuitry. The wireless circuitry may include wireless transceiver circuitry that transmits signals towards an antenna. A signal path may carry the transmitted signals to the antenna. Reflected signals from the antenna may be carried along the signal path towards the transceiver circuitry. Coupler circuitry may include a forward coupler that taps the transmitted signals, a first reverse coupler that taps the reflected signals from the antenna, and a second reverse coupler that taps the reflected signals that have passed through the first reverse coupler. Analog processing circuitry and digital processing circuitry may be used to produce an impedance measurement from the tapped signals from the coupler circuitry. The analog processing circuitry may include analog signal mixers, low pass filters, and analog-to-digital converter circuitry.

Abstract: An electronic device may be provided with wireless circuitry. The wireless circuitry may include one or more antennas. An antenna may have an antenna feed that is coupled to a radio-frequency transceiver with a transmission line. An impedance matching circuit may be coupled to the antenna feed to match the impedance of the transmission line and the antenna. The impedance matching circuit and tunable circuitry in the antenna may be formed using integrated circuits. Each integrated circuit may include switching circuitry that is used in switching components such as inductors and capacitors into use. Sensors such as temperature sensors, current and voltage sensors, power sensors, and impedance sensors may be integrated into the integrated circuits. Each integrated circuit may store settings for the switching circuitry and may include communications and control circuitry for communicating with external circuits and processing sensor data.

Abstract: A service gateway includes a fast path module for processing data packets without using packet buffers and a normal path module for processing data packets using packet buffers. The fast path module receives a service request data packet from a client side session, determines that the service request data packet cannot be processed by the fast path module, and in response, sends the service request data packet to the normal path module. After receiving the service request data packet, the normal path module retrieves a first proxy session record created by the fast path module, where the first proxy session record is associated with a client session record for the client side session, creates a second proxy session record based on the service request data packet and the client session record, and processes the service request data packet according to the second proxy session record.

Abstract: An electronic device may be provided with wireless circuitry. An application processor may generate wireless data that is to be transmitted using the wireless circuitry and may process wireless data that has been received using the wireless circuitry. The wireless circuitry may include multiple baseband processors, multiple associated radios, and front-end module and antenna circuitry. Sensors may be used to provide the application processor with sensor data. During operation, the application processor and the baseband processors may be used to transmit and receive wireless communications traffic. A multiradio controller integrated circuit that does not transmit or receive the wireless communications traffic may be used in controlling the wireless circuitry based on impedance measurements, sensor data, and other information.

Abstract: Electronic devices may be provided that include radio-frequency transceiver circuitry and antennas. An antenna may be formed from an antenna resonating element and an antenna ground. The antenna resonating element may have a shorter portion that resonates at higher communications band frequencies and a longer portion that resonates at lower communications band frequencies. The resonating element may be formed from a peripheral conductive electronic device housing structure that is separated from the antenna ground by an opening. A parasitic monopole antenna resonating element or parasitic loop antenna resonating element may be located in the opening. Antenna tuning in the higher communications band may be implemented using an adjustable inductor in the parasitic element. Antenna tuning in the lower communications band may be implemented using an adjustable inductor that couples the antenna resonating element to the antenna ground.

Abstract: A method for performing keypad input in a portable terminal is provided. The method includes displaying, on a touch screen, a keypad and an operating zone; detecting a first user operation performed in the operating zone; identifying, by a processor, a key from the keypad, the key being identified based on the first user operation; and inputting the selected key.

Abstract: A test system for testing a device under test (DUT) is provided. The test system may include a DUT receiving structure configured to receive the DUT during testing and a DUT retention structure that is configured to press the DUT against the DUT receiving structure so that DUT cannot inadvertently shift around during testing. The DUT retention structure may include a pressure sensor operable to detect an amount of pressure that is applied to the DUT. The DUT retention structure may be raised and lowered vertically using a manually-controlled or a computer-controlled positioner. The positioner may be adjusted using a coarse tuning knob and a fine tuning knob. The positioner may be calibrated such that the DUT retention structure applies a sufficient amount of pressure on the DUT during production testing.

Abstract: An electronic device may have control circuitry that uses a reflectometer to measure antenna impedance during operation. The reflectometer may have a directional coupler that is coupled between radio-frequency transceiver circuitry and an antenna. A calibration circuit may be coupled between the directional coupler and the antenna. The calibration circuit may have a first port coupled to the antenna, a second port coupled to the directional coupler, and a third port that is coupled to a calibration resistance. The reflectometer may have terminations of identical impedance that are coupled to ground. Switching circuitry in the reflectometer may be used to route signals from the directional coupler to a feedback receiver for measurement by the control circuitry or to ground through the terminations. Calibrated antenna reflection coefficient measurements may be used in dynamically adjusting the antenna.

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.