A amplifier device includes an amplifier, a coupling circuit, and a filter circuit. The amplifier amplifies a high frequency signal, and outputs to signal output ports the high frequency signal. The coupling circuit is provided side-by-side with the amplifier in a first direction on a substrate, connected to the signal output ports, and configured to couple output signals and output one output signal to an output terminal. The filter circuit is provided on the substrate and connected to the coupling circuit, and configured to reduce third-order IMD included in the one output signal. The one output signal is output from a middle of the substrate in a second direction intersecting with the first direction, and the filter circuit is arranged next to an edge of the substrate in the second direction, and arranged next to an edge of the substrate on the output terminal side in the first direction.

A multiplexer includes: a first terminal; a second terminal; a third terminal; a first filter connected between the first and second terminals, including a first capacitor, a first inductor, and one or more first acoustic wave resonators, and having a first passband; a second filter connected between the first and third terminals, including a second capacitor, a second inductor, and one or more second acoustic wave resonators, and having a second passband higher than the first passband; a substrate having a surface on which at least one first acoustic wave resonator of the one or more first acoustic wave resonators and at least one second acoustic wave resonator of the one or more second acoustic wave resonators are located; and a metal structure located on the surface and located between the at least one first acoustic wave resonator and the at least one second acoustic wave resonator.

A power amplifier device includes a first amplifier, a second amplifier, a capacitor, a node, and an impedance matching circuit. The second amplifier amplifies a radio frequency signal transmitted from the first amplifier. The capacitor is coupled between an output terminal of the first amplifier and an input terminal of the second amplifier. The node is disposed between the input terminal of the second amplifier and the capacitor. The impedance matching circuit is coupled to the node and a common voltage terminal. The impedance matching circuit is substantially an open circuit at a center frequency of the radio frequency signal. The impedance matching circuit provides substantially a short-circuited path from the node to the common voltage terminal at a frequency twice the center frequency.

Examples provide a wideband filter structure and apparatus, a radio transceiver, a mobile terminal, and a method for filtering a radio signal. The wideband filter structure (10) for a radio signal comprises a combination of at least one acoustic resonator (12) and at least one analog resonator (14). The acoustic resonator (12) is coupled to the analog resonator (14). The wideband filter structure (10) comprises a further component (16), which is coupled to the combination of the acoustic resonator (12) and the analog resonator (14).

Aspects of the present disclosure provide three-dimensional (3D) through-glass-via (TGV) inductors for use in electronic devices. In some embodiments, a first portion of a 3D TGV inductor may be formed in a first wafer and a second portion of a 3D TGV may be formed in a second wafer. The first portion and second portion may be bonded together in a bonded wafer device thereby forming a larger inductor occupying relatively little wafer space on the first and the second wafers.

A resonant circuit includes a first inductor and a first capacitor which define a first series circuit and a second inductor connected in parallel to the first series circuit. The first inductor and the second inductor are coupled via a magnetic field in a direction in which magnetic fluxes passing through the inductor and the second inductor strengthen each other to effectively increase steepness in a transient band.

A radio frequency (RF) filter circuit for rejecting one or more spurious components of an input signal has a first resonator circuit including a first capacitor and a first coupled inductor pair of a first inductor and a second inductor, and a second resonator circuit with a second capacitor and a second coupled inductor pair of a third inductor and a fourth inductor. First and second resonator coupling capacitors are connected to the first resonator circuit and the second resonator circuit. A first port and a second port are connected to the first resonator circuit and the second resonator, with the filtered signal of the input signal passed through both the first resonator circuit and the second resonator circuit being output.

Certain aspects of the present disclosure provide a filter circuit and techniques for filtering using the filter circuit. The filter circuit generally includes a first filter stage having a first acoustic wave resonator coupled in a series path between a first port of the filter circuit and a second port of the filter circuit, a first inductor-capacitor (LC) tank circuit, a first capacitor coupled between a first terminal of the first acoustic wave resonator and the first LC tank circuit, the first LC tank circuit being coupled between the first capacitor and a reference potential node, and a second capacitor coupled between a second terminal of the first acoustic wave resonator and the first LC tank circuit. In some aspects, the filter circuit includes one or more other filter stages coupled to the first filter stage.

A dual mode notch filter for use in a multi-band millimeter wave (mmW) transmitter includes a transmit filter circuit disposed between two amplifiers in a mmW transmit signal path, the transmit filter circuit formed by at least one switch, at least one capacitor, and a double-tuned transformer, the transmit filter circuit having at least two modes configured to selectively filter a spurious signal in at least a first communication band.

A trap filter includes a first inductor, a second inductor, and a capacitor. A first end of the first inductor extends to a first connection portion, a third end of the second inductor is connected to a second end of the first inductor, and a fourth end extends to a second connection portion. The capacitor is connected in parallel with the second inductor. The first inductor and the second inductor are subtractive-polarity coupled. An inductance value of the second inductor is less than an absolute value of mutual inductance generated by coupling of the first inductor and the second inductor.