Abstract: An electronic device may include isolation circuitry coupled between a transmitter, a receiver, and one or more antennas. The isolation circuitry may include a 90 degree hybrid coupler configured receive a transmission (TX) signal from the transmitter, split the TX signal into a first portion and a second portion, and phase-shift a portion such that the portions are +90 degrees out-of-phase. The isolation circuitry may include phase shifters that phase-shift the portions such that the portions are in-phase prior to propagating to the antenna. The phase shifters may receive a first portion and a second portion of a receiver (RX) signal from splitter circuitry. The phase shifters may phase-shift the portions such that the portions are out-of-phase by ?90 degrees. The 90 degree hybrid coupler may phase-shift the first portion and/or the second portion such that the portions are in-phase and constructively combine prior to propagating to the receiver.

Abstract: Systems and methods combine a test signal with a wanted (downlink or uplink) signal at an input of a duplexer of a communication device, and receive the test signal at an output of the duplexer. The test signal may include a radio frequency signal having less power than the wanted signal to avoid interference, or a digital signal that is added to or extracted from the wanted signal when the wanted signal does not have a radio frequency. A processor of the communication device causes the duplexer to operate in a tuning state (e.g., to transmit signals having a transmission frequency and receive signals having a receive frequency). The measurement system determines a difference or ratio in power between the test signal at the duplexer output and the duplexer input, and adjusts the tuning state based on the difference or ratio (e.g., to decrease or minimize the difference or ratio).

Abstract: Systems and methods combine a test signal with a wanted (downlink or uplink) signal at an input of a duplexer of a communication device, and receive the test signal at an output of the duplexer. The test signal may include a radio frequency signal having less power than the wanted signal to avoid interference, or a digital signal that is added to or extracted from the wanted signal when the wanted signal does not have a radio frequency. A processor of the communication device causes the duplexer to operate in a tuning state (e.g., to transmit signals having a transmission frequency and receive signals having a receive frequency). The measurement system determines a difference or ratio in power between the test signal at the duplexer output and the duplexer input, and adjusts the tuning state based on the difference or ratio (e.g., to decrease or minimize the difference or ratio).

Abstract: A communication device includes an antenna tracker having a circuit architecture that includes at least one L-C resonance circuit component with an adjustable resonance frequency value. In particular, each of the L-C resonance circuit components may include a tunable capacitor and an inductor coupled in parallel. The antenna tracker may be single-ended and include at least one ground coupling, while in some embodiments, the antenna tracker may be differential. The circuit architecture of the antenna tracker may enable the antenna tracker to increase an impedance coverage range of the communication device, thus increasing a range of impedance within which an antenna impedance may be effectively tracked and matched, enabling effective isolation between the transmitter and receiver across an increased range of antenna impedance.

Abstract: An amplifier (e.g., a low noise amplifier (LNA)) may operate in multiple modes, including a first, default mode (e.g., a high gain and/or power-saving mode) which may apply when an out-of-band blocker signal (e.g., transmitted or received by other radios, transceivers, or devices) is not present. The LNA may also operate in a second, Long Term Evolution (LTE) blocking or high linearity mode, which may be selected when a blocker and/or transmission signal leakage is present during, for example, LTE operation. The LNA may further operate in a third, Global System for Mobile (GSM) blocking mode, which may include a high compression point to withstand a GSM blocker that may be present during, for example, GSM operation. The LNA may also operate in a protection mode when voltage of a received signal is excessive to protect the LNA or device having the LNA.

Abstract: A differential double balanced duplexer (dDBD) includes a transmitter and a first balun are coupled to a first impedance tuner that produces a first impedance that blocks received signals at a first frequency range from travelling across the first balun and into the transmitter, and a second impedance that passes transmitted signals at a second frequency range to travel across the first balun to the antenna. The dDBD also includes a receiver and a second balun coupled to a second impedance tuner that produces a first impedance that allows the received signals at the first frequency range to travel across the second balun and into the receiver, and a second impedance that blocks the transmitted signals at the second frequency range from travelling across the second balun and into the receiver. As such, the dDBD allows for increased isolation and decreased insertion loss.

Abstract: In electronic devices used in radio-frequency communications, impedance matching may result in desirable operating conditions. However, impedance of the antenna may change over time (e.g., due to frequency of signals being transmitted or received, due to ambient conditions, due to age of antenna or related components). Accordingly, it may be desirable to employ antenna tracking circuitry that may operate as an impedance matching network to dynamically match the antenna impedance. To dynamically match the antenna impedance, the matching network may include tunable components. To provide fast, dynamic, and effective impedance matching, antenna tracking circuitry having an architecture with analytically determinable impedance (e.g., determinable via one or more equations) may be implemented. The antenna tracking circuitry may include a variable resistor and three variable impedances.

Abstract: An electronic device may include isolation circuitry coupled between a transmitter, a receiver, and one or more antennas. The isolation circuitry may include a 90 degree hybrid coupler configured receive a transmission (TX) signal from the transmitter, split the TX signal into a first portion and a second portion, and phase-shift a portion such that the portions are +90 degrees out-of-phase. The isolation circuitry may include phase shifters that phase-shift the portions such that the portions are in-phase prior to propagating to the antenna. The phase shifters may receive a first portion and a second portion of a receiver (RX) signal from splitter circuitry. The phase shifters may phase-shift the portions such that the portions are out-of-phase by ?90 degrees. The 90 degree hybrid coupler may phase-shift the first portion and/or the second portion such that the portions are in-phase and constructively combine prior to propagating to the receiver.

Abstract: An electronic device may include wireless circuitry with a processor, a transceiver circuit, a front-end module, and an antenna. The front-end module may include amplifier circuitry such as a low noise amplifier for amplifying received radio-frequency signals. The amplifier circuitry may operation in different modes based on its operating environment. Accordingly, the amplifier circuitry may include multiple amplifying cascode stages coupled in parallel, some of which may be selectively enabled. The amplifier circuitry may include an intermodulation distortion suppression circuit coupled to an amplifying cascode stage and an n-path filter coupled to another amplifying cascode stage. One or more of these amplifier circuitry portions may be active depending on its operating mode.

Abstract: A communication device includes a duplexer differentially coupled to a receiver and a transmitter. The duplexer may include phase shifters on the differential lines to provide differential received signals to the receiver and receive differential transmission signals from the transmitter for transmission. For example, the phase shifter are positioned such that single-ended received signals may be converted to differential received signals and convert the differential transmission signals to single-ended transmission signals for transmission. Moreover, the phase shifters may provide the single-ended transmission signals to antennas for transmission and to the differential lines of the receiver for cancellation/isolation. Furthermore, the phase shifters may provide the differential received signals to the receiver for reception and provide the single-ended received signals to the differential lines of the transmitter for cancellation/isolation.

Abstract: Systems and methods combine a test signal with a wanted (downlink or uplink) signal at an input of a duplexer of a communication device, and receive the test signal at an output of the duplexer. The test signal may include a radio frequency signal having less power than the wanted signal to avoid interference, or a digital signal that is added to or extracted from the wanted signal when the wanted signal does not have a radio frequency. A processor of the communication device causes the duplexer to operate in a tuning state (e.g., to transmit signals having a transmission frequency and receive signals having a receive frequency). The measurement system determines a difference or ratio in power between the test signal at the duplexer output and the duplexer input, and adjusts the tuning state based on the difference or ratio (e.g., to decrease or minimize the difference or ratio).

Abstract: Systems and methods combine a test signal with a wanted (downlink or uplink) signal at an input of a duplexer of a communication device, and receive the test signal at an output of the duplexer. The test signal may include a radio frequency signal having less power than the wanted signal to avoid interference, or a digital signal that is added to or extracted from the wanted signal when the wanted signal does not have a radio frequency. A processor of the communication device causes the duplexer to operate in a tuning state (e.g., to transmit signals having a transmission frequency and receive signals having a receive frequency). The measurement system determines a difference or ratio in power between the test signal at the duplexer output and the duplexer input, and adjusts the tuning state based on the difference or ratio (e.g., to decrease or minimize the difference or ratio).