Abstract: An apparatus is disclosed for passive intermodulation distortion filtering. The apparatus includes a radio-frequency front-end circuit. The radio-frequency front-end circuit includes a transmit filter circuit and a receive filter circuit. The transmit filter circuit includes a passive circuit configured to combine at least two radio-frequency transmit signals associated with different transmit frequency bands. The transmit filter circuit also includes a filter coupled between the passive circuit and a first feed of an antenna. The filter is configured to attenuate frequencies associated with a receive frequency band. The receive filter circuit is coupled to a second feed of the antenna and is configured to pass the frequencies associated with the receive frequency band.

Abstract: An intermodulation distortion canceller for use in multi-carrier transmitters is disclosed. In an exemplary embodiment, an apparatus includes a first transmit chain that transmits a first RF signal, a second transmit chain that transmits a second RF signal, and a canceller that outputs a first leakage cancellation signal that is input to the second transmit chain, and outputs a second leakage cancellation signal that is input to the first transmit chain, the canceller generates the first and second leakage cancellation signals from the first and second RF signals or from first and second baseband signals used to generate the first and second RF signals.

Abstract: An intermodulation distortion canceler for use in multi-carrier transmitters is disclosed. In an exemplary embodiment, an apparatus includes a first transmit chain that transmits a first RF signal, a second transmit chain that transmits a second RF signal, and a canceler that outputs a first leakage cancellation signal that is input to the second transmit chain, and outputs a second leakage cancellation signal that is input to the first transmit chain, the canceler generates the first and second leakage cancellation signals from the first and second RF signals or from first and second baseband signals used to generate the first and second RF signals.

Abstract: Certain aspects of the present disclosure provide a dual antenna distributed radio frequency front end (RFFE). RFFE topologies described herein may provide lower insertion loss (IL), reduced emission mask, decreased power consumption, and/or lower noise figure (NF) compared to conventional RFFE topologies. One example apparatus for wireless communications generally includes first and second power amplifiers (PAs) for amplifying signals for transmission, a transmit antenna for transmitting the amplified signals, a receive antenna for receiving other signals to be processed in a receive path, and a first transmit filter configured to filter the amplified signals from the first PA before amplification by the second PA. For certain aspects, a divided inter-stage filter providing overlapping frequency bands may be utilized. For certain aspects, the RFFE may support frequency-division duplexing (FDD)/TDD (time-division duplexing) coexistence, including support for FDD/TDD MIMO (multiple input multiple output).