Embodiments of the present invention provide an apparatus and a method for interference cancellation. The apparatus includes: a splitter, configured to acquire a first transmit signal and a second transmit signal; a first circulator, configured to transmit the first transmit signal to an antenna and to send a to-be-processed signal to a combiner, where the to-be-processed signal includes a receive signal component and a self-interference signal component, the self-interference signal component corresponds to an interference signal generated due to that the antenna reflects the first transmit signal; a second circulator, configured to: transmit the second transmit signal to an equivalent load, and acquire a reference signal generated due to that the equivalent load reflects the second transmit signal, where an impedance of the equivalent load corresponds to an impedance of the antenna; and a combiner, configured to cancel the self-interference signal component according to the reference signal.

A directional power detector device includes a directional coupling network including a first transmission path connected between a radio frequency (RF) input and an RF output, the first transmission path having a voltage transmission gain A, phase θ and characteristic impedance Zo, a second transmission path having the same voltage transmission gain A, phase θ and characteristic impedance Zo, and a resistor connected between the first transmission path at the RF output and the second transmission path, where the resistor has a value including the characteristic impedance Zo. The directional power detector device further includes a detector diode including an anode connected to the second transmission path and a cathode, a capacitor connected between the cathode of the detector diode and the RF input port, and a detector output connected to the cathode of the detector diode. The detector outputs a DC detector voltage when a forward RF signal is applied to the RF input, and outputs zero DC detector voltage when reverse RF signal is applied to the RF output.

A network interface device has a safeguard apparatus. The safeguard apparatus is operable in power on, power off, and degraded power conditions. In power on operation, the safeguard apparatus maintains the quality of active and passive branch communications. During power off and degraded power operation, the safeguard apparatus safeguards the quality of the passive communication path.

According to embodiments of the present invention, a switching circuit is provided. The switching circuit includes a transmission line arrangement including a plurality of transmission lines coupled to each other, and at least one switching element arrangement coupled to at least one transmission line of the plurality of transmission lines, wherein, in a first mode of operation, the at least one switching element arrangement is configured in a first state, wherein, in a second mode of operation, the at least one switching element arrangement is configured in a second state, and wherein the transmission line arrangement is configured to, depending on whether the at least one switching element arrangement is configured in the first state or the second state, generate a standing wave from an input signal received by the transmission line arrangement for coupling into an output signal, wherein the output signal is transmitted from the transmission line arrangement.

According to embodiments of the present invention, a switching circuit is provided. The switching circuit includes a transmission line arrangement including a plurality of transmission lines coupled to each other, and at least one switching element arrangement coupled to at least one transmission line of the plurality of transmission lines, wherein, in a first mode of operation, the at least one switching element arrangement is configured in a first state, wherein, in a second mode of operation, the at least one switching element arrangement is configured in a second state, and wherein the transmission line arrangement is configured to, depending on whether the at least one switching element arrangement is configured in the first state or the second state, generate a standing wave from an input signal received by the transmission line arrangement for coupling into an output signal, wherein the output signal is transmitted from the transmission line arrangement.

The present disclosure includes dynamic power divider circuits and methods. In one embodiment, a dynamic power divider includes first and second quarter wave lines that receive an input signal and produce first and second signal on second terminals of the lines. Dynamic power division of the input signal uses a variable impedance circuit between the second terminal of the first quarter wave line and the second terminal of the second quarter wave line. The variable impedance may reduce impedance between two output paths as the input signal power increases or increase impedance between the output paths as the input signal power decreases.

The present disclosure includes dynamic power divider circuits and methods. In one embodiment, a dynamic power divider includes first and second quarter wave lines that receive an input signal and produce first and second signal on second terminals of the lines. Dynamic power division of the input signal uses a variable impedance circuit between the second terminal of the first quarter wave line and the second terminal of the second quarter wave line. The variable impedance may reduce impedance between two output paths as the input signal power increases or increase impedance between the output paths as the input signal power decreases.

A power dividing circuit includes a first transmission sub-circuit having an input port and a first resonant circuit, a second transmission sub-circuit having a second resonant circuit, and a third transmission sub-circuit having a third resonant circuit. A matching element is coupled between the second transmission sub-circuit and the third transmission sub-circuit. An input carrier signal is divided into a first signal to the second transmission sub-circuit and a second signal to the third transmission sub-circuit through the first transmission sub-circuit. The second resonant circuit and the third resonant circuit generate resonant frequency to reduce high frequency harmonics under a specific frequency range in the input carrier signal. A power divider is also provided.

A MoCA splitter device may include an input port, a first output port and a second output port, a first transmission line configured to connect the input port to the first output port, a second transmission line configured to connect the input port to the first output port, a first isolation element configured to connect the first transmission line to the second transmission line, a second isolation element configured to connecting the first transmission line to the second transmission line. The first isolation element and the second isolation element are configured to provide an isolation level between the first output port and the second output port that is less than a predetermined isolation level of about less than 16 dB in a MoCA frequency band.

The isolated port of a 0/90 degree coupler is terminated by a novel complex termination impedance circuit having a reactance. The absolute value of the reactance is at least two ohms. The coupler receives a signal on its input port, and outputs a first signal on its first output port and a second signal on its second output port. A first load is coupled to the first output port without an intervening matching network. A substantial impedance mismatch exists between the first output port and the first load. A second load is coupled to the second output port without an intervening matching network. A substantial impedance mismatch exists between the second output port and the second load. Despite the substantial impedance mismatches, the first and second signals have a phase difference in a range of from 88 degrees to 92 degrees while exhibiting an amplitude imbalance less than 2 dB.