An acoustic wave device includes a piezoelectric substrate made of LiNbO.sub.3, and a dielectric film provided on the piezoelectric substrate to cover first and second IDT electrodes on the piezoelectric substrate. The first and second IDT electrodes include main electrode layers. When wave lengths determined by electrode finger pitches of the first and second IDT electrodes are .sub.1 and .sub.2, respectively, the average value thereof is .sub.0, .sub.1/.sub.0=1+X, and .sub.2/.sub.0=1X, a relationship of 0.05X0.65 is satisfied. The wavelength .sub.1 is the longest, and the wavelength .sub.2 is the shortest. In Euler angles (, , ) of the piezoelectric substrate, is 05, is 010, and satisfies Expression 1, wherein a relationship of B.sub.1-<Tr0.10.sub.0 and B.sub.2<Tr0.10.sub.0 are satisfied.

An acoustic wave device includes a piezoelectric body made of lithium niobate and disposed directly or indirectly on a supporting substrate, and IDT electrode disposed directly or indirectly on the piezoelectric body. When the wavelength of an acoustic wave that is determined by a pitch of electrode fingers of the IDT electrode is denoted by , the thickness of the piezoelectric body is equal to or less than about 1. The acoustic wave device uses the plate wave S0 mode propagating in the piezoelectric body. The Euler angles of the lithium niobate are (010, , 9010), provided that is from about 0 to about 180 inclusive.

Systems, devices, and methods for adjusting tuning settings of tunable components, such as tunable capacitors, can be configured for calibrating a tunable component. Specifically, the systems, devices and methods can measure a device response for one or more inputs to a tunable component, store a calibration code in a non-volatile memory that characterizes the device response of the tunable component, and adjust a tuning setting of the tunable component based on the calibration code to achieve a desired response of the tunable component.

An embodiment of the present invention provides greater isolation between a port serving as a Tx port and a port serving as an Rx port in a diplexer. A diplexer (1) includes: a filter pair (11) constituted by first and second filters (12, 13) having a passband which is a first frequency band, the first and second filters being arranged next to each other; first and second directional coupler sections (21, 31), each of which is connected to a respective one of opposite sides of the filter pair (11); and a third filter (41) which is connected to a port (third port 213) of the first directional coupler section (21) on a side away from the filter pair (11), the third filter having a passband which is a second frequency band.

A tunable filter includes at least two tunable resonators, a resonator comprising at least one inductance or transmission line, the inductance or transmission line having a first end connected to the ground M and a second end coupled to another resonator via a coupling impedance, and several switched capacitors, wherein the inductance or transmission line comprises several access points or connection points distributed along the inductance allowing for the connection or non-connection of a switched capacitor whose value is defined as a function of its position on the inductance, the capacitors of low weights are situated close to the end of the inductance linked to the ground M. A use of the filter in radio transceivers is also provided.

Various embodiments of the invention relate to a high performance analog bandpass filter (BPF) with improved performance in suppressing parasitic passband. The BPF comprises a first loss-pass filter (LPF) coupled to a first RF port, a second LPF coupled to a second RF port, and at least one high-pass module coupled in series between the first LPF and the second LPF for band-pass tuning. A resonant circuit is composed by a shunt capacitor from the LPF, a shunt inductor from the high-pass module and a series inductor from the LPF coupled in between. Such layout empowers the LPFs triple functions: to function as a low-pass filter, to participate in resonant circuit for center frequency tuning of the BPF, and to suppress parasitic resonance. Such a triple-function of the LPFs gives the BPF an improvement in a compact but effective topology.

The invention relates to an HF circuit, for example for use in front-end circuits, having improved signal quality in carrier aggregation. According to the invention, a signal path between a duplexer and a diplexer comprises a phase shifter.

A cascading microwave switch (cascade) includes a set of Josephson devices, each Josephson device in the set having a corresponding operating bandwidth of microwave frequencies, wherein different operating bandwidths have different corresponding center frequencies. A series coupling is formed between first Josephson device from the set and an n.sup.th Josephson device from the set, wherein the series coupling causes the first Josephson device in an open state to reflect back to an input port of the first Josephson device a signal of a first frequency from a frequency multiplexed microwave signal (multiplexed signal) and the n.sup.th Josephson device in the open state to reflect back to an input port of the n.sup.th Josephson device a signal of an n.sup.th frequency from the multiplexed signal.

A filter includes a resonant circuit defining at least a portion of a signal path connected between a first terminal and a second terminal, an elastic wave resonator including one end that is grounded, a first inductor including one end connected to one end of the resonant circuit and another end connected to another end of the elastic wave resonator, and a second inductor including one end connected to another end of the resonant circuit and another end connected to the other end of the elastic wave resonator. The resonant circuit is an LC series resonant circuit in which a third inductor and first and second capacitors are connected in series with each other.

A voltage-controlled oscillator (VCO) includes a power supply node configured to have a power supply voltage. A reference node is configured to have a first reference voltage. A transformer-coupled band-pass filter (BPF) is coupled to a cross-coupled pair of transistors. The cross-coupled pair of transistors and the transformer-coupled band-pass filter are positioned between the power supply node and the reference node.