Systems, devices, and methods for tunable filters that are configured to support multiple frequency bands, such as within the field of cellular radio communication, can include a first resonator and a second resonator configured to block signals within one or more frequency ranges, and one or more coupling element connected to both the first resonator and the second resonator. The one or more coupling element can be configured to provide low insertion loss within a pass band.

Apparatus and methods for tunable filters are provided. In certain configurations, a tunable filter includes a semiconductor die attached to a laminated substrate, such as a substrate of a multi-chip module (MCM). The tunable filter includes a vector inductor implemented using two or more conductors arranged on different conductive layers of the laminated substrate. The vector inductor's conductors are inductively coupled to one another and electrically connected in parallel to provide the vector inductor with high quality factor (Q-factor). The semiconductor die includes a variable capacitor that is electrically connected with the vector inductor to operate as a tunable resonator. Additionally, a frequency characteristic of the tunable filter, such as a passband, can be controlled by selecting a capacitance value of the variable capacitor, thereby tuning a resonance of the resonator.

A package for a tunable filter is disclosed. In an embodiment, the tunable filter includes a substrate having a first interconnection plane and a semiconductor device assembled on the substrate in a first component plane, the semiconductor device electrically connected to the first interconnection plane and containing tunable passive components. The filter further includes a control unit arranged in the first component plane, a dielectric layer arranged above the first component plane, a second component plane arranged on the dielectric layer and discrete passive devices arranged in the second component plane and interconnected with the semiconductor device, wherein the tunable passive components are tunable by the control unit.

A multilayer triplexer includes a first coil connected between a common terminal and a first filter, a second coil connected between the common terminal and a second filter, and a third coil connected between the common terminal and the third filter. The first coil, the second coil, and the third coil each include a coil conductor pattern between ones of substrate layers of a multilayer body. The coil conductor pattern of the first coil, the coil conductor pattern of the second coil, and the coil conductor pattern of the third coil do not overlap each other when the multilayer body is seen through in a direction in which the substrate layers are stacked on one another.

An adjustable inductor including a toroidal core defining a plurality of gaps, a compressible gap material positioned in the gaps, at least one winding wound on the core, a force-applying structure, and a film substantially covering the adjustable inductor. The force-applying structure is operable to apply a force to the core to adjust the gaps and thereby an inductance of the adjustable inductor. The film is configured to prevent movement of force-applying structure when above a predetermined temperature threshold, and allow movement of the force-applying structure when below the predetermined threshold.

A variable-frequency resonance circuit includes first and second input/output terminals and a resonance circuit portion. The resonance circuit portion includes a first inductor and first and second LC series circuits. The resonance circuit portion is connected between a ground and a transmission line that connects the first and second input/output terminals. The first LC series circuit includes a second inductor and a variable capacitor connected in series with each other. The second LC series circuit includes a third inductor and a fixed capacitor connected in series with each other. The first and second LC series circuits are connected in parallel between the first inductor and a ground. The first and second inductors are configured such that positive-coupling mutual inductance is produced therebetween.

An all-pass filtering module of a common mode noise suppressing device includes first and second differential transmission circuits coupled to a reference node. Each of the first and second differential transmission circuits has an input terminal and an output terminal, and includes: first and second capacitive elements coupled in series between the input terminal and the output terminal; a first inductor coupled between the input terminal and the output terminal; and a third capacitive element and a second inductor coupled in series between the reference node and a common node between the first and second capacitive elements.

A tunable duplexer circuit is described, wherein the frequency response as well as bandwidth and transmission loss characteristics can be dynamically altered, providing improved performance for transceiver front-end applications. The rate of roll-off of the frequency response can be adjusted to improve performance when used in duplexer applications. A method is described where the duplexer circuit characteristics are optimized in conjunction with a specific antenna frequency response to provide additional out-of-band rejection in a communication system. Dynamic optimization of both the duplexer circuit and an active antenna system is described to provide improved out-of-band rejection when implemented in RF front-end circuits of communication systems. Other features and embodiments are described in the following detailed descriptions.

The present invention provides an electrical filter device (1) for filtering a common-mode interference between a current source and a load, comprising:—a signal input (E), which comprises at least one first terminal (E1) and can be connected to the current source; —a signal output (A), which can be connected to the load; —a main stage (H0), having a first main inductor (2a), which comprises a coil with a first core (3), the first main inductor (2a) being connected to the first terminal (E1); and—an auxiliary stage (H1), having at least one first anti-interference capacitor (C1) and one first auxiliary inductor (4), the first auxiliary inductor (4) being connected between the first terminal (E1) and the first anti-interference capacitor (C1), the first auxiliary inductor (4) being inductively coupled to the first main inductor (2a).

A circuit device includes a substrate, and a wiring pattern and a coil component on the substrate. The wiring pattern includes a first land electrode connected to a first electrode of the coil component and a second land electrode connected to a second electrode of the coil component. The wiring pattern includes a wiring line electrically connected to the land electrode at a position shifted along a first side surface from a center of the first side surface by a shifting value and a wiring line electrically connected to the land electrode at a position shifted along a second side surface from a center of the second side surface by a shifting value.