An acoustic wave filter includes a first signal terminal, an antenna terminal, a ladder-type filter connected between the first signal terminal and the antenna terminal and including one or more serial resonators and one or more parallel resonators connected in a ladder shape, and a capacitor part and an inductor part which are connected in series between the first signal terminal and a reference potential.

A multiplexer includes a transmission filter and a reception filter connected to a common terminal, a first inductor connected to the common terminal, and a multilayer substrate on which the transmission filter and the reception filter are mounted and which includes dielectric layers. The transmission filter includes a parallel-arm resonator connected to a path between the common terminal and a transmission terminal and a parallel-arm terminal, and a second inductor connected to the parallel-arm terminal and ground. The first inductor includes a first coil pattern on a first dielectric layer and a second coil pattern on a second dielectric layer. The second inductor includes a third coil pattern on the first dielectric layer and that is magnetically coupled to the first coil pattern. The inductance value of the second coil pattern is greater than that of the first coil pattern.

Certain disclosed embodiments pertain to suppressing interference in a wireless communication system. For example, a method of suppressing interference can include receiving one, two, or more first signals including components from a plurality of sub-channels. Each of the first signals can be processed by a Finite Impulse Response filter adapted using an LMS update algorithm,

A system for interference mitigation includes: a first transmit coupler; a receive-band noise cancellation system; a first transmit-band filter; a second transmit coupler; a first receive coupler; a transmit-band noise cancellation system; a first receive-band filter; and a second receive coupler.

Disclosed is a transmission radio frequency (RF) circuit including a transmission mixer configured to receive an intermediate frequency (IF) signal and up-convert the IF signal into an RF signal, a driving amplifier configured to amplify the RF signal, and an LLC filter electrically connected to a differential output of the transmission mixer and a differential input of the driving amplifier, the LLC filter comprising a first inductor connecting a first node of the differential output of the transmission mixer to a first intermediate node, a second inductor connecting a second node of the differential output of the transmission mixer to a second intermediate node, a third inductor connecting the first intermediate node to the second intermediate node, and a capacitor in parallel with the third inductor.

A transmission device includes a signal source configured to output a local signal with a first frequency, a first amplifier configured to amplify the local signal output from the signal source, a first mixer configured to mix a first input signal with an intermediate frequency and the local signal amplified by the first amplifier and to output a first output signal, and a second mixer configured to mix the first output signal output from the first mixer and the local signal amplified by the first amplifier and to output a second output signal.

A RF system and an electronic device are provided. The RF system includes an RF transceiver, an RF processing circuit, a transfer switch module, and four antennas. The RF processing circuit includes a first TX module, a second TX module, a first RX module, a second RX module, a first duplexer, a second duplexer, a first multiplexer, and a first filtering module. When the RF system works in a NSA mode, a first antenna is configured for TX of a first LB and PRX of the first LB, a second antenna is configured for TX of a second LB and PRX of the second LB, a third antenna is configured for DRX of the second LB, a fourth antenna is configured for DRX of the first LB, and the first filtering module is configured to filter a band other than the first LB.

Aspects are provided for multiband multiplexers. One example is a multiband multiplexer with a first filter element configured to have a first passband that spans a first predefined frequency range of a first communication band and a second predefined frequency range of a second communication band, wherein the first predefined frequency range overlaps a portion of the second predefined frequency range, a second filter element configured to have a second passband distinct from the first passband, a third filter element configured to have a third passband distinct from the first and second passbands, and a fourth filter element configured to have a fourth passband distinct from the first, second, and third passbands.

An acoustic wave device includes a support substrate made of silicon, a piezoelectric body provided directly or indirectly on the support substrate, the piezoelectric body including a pair of main surfaces facing each other, and an interdigital transducer electrode provided directly or indirectly on at least one of the main surfaces of the piezoelectric body, a wave length that is determined by an electrode finger pitch of the interdigital transducer electrode being λ. An acoustic velocity V.sub.Si=(V.sub.1).sup.1/2 of bulk waves that propagate in the support substrate, which is determined by V.sub.1 out of solutions V.sub.1, V.sub.2, V.sub.3 of x derived from the expression, Ax.sup.3+Bx.sup.2+Cx+D=0, is higher than or equal to about 5500 m/s.

An antenna module includes a dielectric substrate, a ground electrode, a power feeding element (121) and a power feeding element (122) each facing the ground electrode, and power feeding wirings (141) and (142). The power feeding wiring (141) transmits a radio frequency signal to a power feeding point (SP1) of the power feeding element (121). The power feeding wiring (142) transmits a radio frequency signal to a power feeding point (SP2) of the power feeding element (122). A frequency of a radio wave from the power feeding element (122) is higher than a frequency of a radio wave from the power feeding element (121). The power feeding wiring (142) includes a via rises from the ground electrode side to the power feeding element (122) at a position different from the power feeding point (SP2) and a wiring pattern that connects the via and the power feeding point (SP2).