A filter includes a first capacitor connected in series between a first terminal pair and a second terminal pair, a first inductor connected in parallel with the first capacitor, and a second inductor connected in parallel between the first terminal pair and the second terminal pair. The first inductor and the second inductor are magnetically coupled to each other and are differentially connected to each other.

The disclosure relates to an ultra-wide passband five-order band-pass filter based on an LTCC process. The ultra-wide passband five-order band-pass filter comprises a ceramic substrate, a bottom input electrode, a bottom output electrode and a bottom grounding electrode. Five parallel resonators, a grounding polar plate, two series connection capacitors, two series connection inductors, a cross-coupling capacitor and a parallel inductor are arranged in the ceramic substrate; the two series connection capacitors comprise a first series capacitor and a second series capacitor; the two series connection inductors comprise a first series inductor and a second series inductor; and according to the filter, a five-order parallel resonance structure is adopted, out-of-band suppression is deepened through the five parallel resonance units, a cross coupling capacitor, a parallel inductor and two series connection inductors are innovatively introduced.

An LC resonator includes first and second plane electrodes, a first line electrode, a first and second via conductors, and a third plane electrode. The second plane electrode is opposed to at least a portion of the first plane electrode in a specific direction. The first via conductor and the second via conductor extend from the first line electrode in the specific direction to be connected to the first plane electrode and the second plane electrode, respectively. The third plane electrode is opposed to at least a portion of the second plane electrode in the specific direction. The second plane electrode is between the first plane electrode and the third plane electrode in the specific direction.

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 multilayer filter may include a signal path having an input, an output, and a conductive layer overlying at least one of a plurality of dielectric layers. The conductive layer may be elongated in the first direction and may have a first edge aligned with the first direction and a second edge parallel with the first edge. The conductive layer may include a protrusion extending in the second direction and having an end edge that is parallel with the first edge and offset from the first edge in the second direction by a protrusion length that is greater than about 50 microns. The multilayer filter may include an inductor that is electrically connected at a first location with the signal path and electrically connected at a second location with at least one of the signal path or a ground.

An integrated passive die includes a substrate, an input node, an output node, and RF filtering circuitry. The RF filtering circuitry includes a number of LC tank circuits coupled between the input node and the output node. Each one of the LC tank circuits include an inductor and a capacitor. The inductor is formed by a metal trace over the substrate. The capacitor is coupled in parallel with the inductor over the substrate. The inductor and the capacitor are provided such that a resonance frequency of the combination of the inductor and the capacitor is less than a self-resonance frequency of the inductor.

A resonant element includes first, second, and third plane electrodes, a first via electrode defining a first inductor, a second inductor, and a third inductor. The first via electrode connects the first plane electrode and the second plane electrode, and each of the second inductor and the third inductor connects the first plane electrode and the third plane electrode. The third plane electrode defines a first capacitor together with the second plane electrode, the second inductor includes second via electrodes, and the third inductor includes third via electrodes. Each of the second via electrodes and the third via electrodes is a columnar conductor extending in the extending direction of the first via electrode.

A frontend module includes a first filter having a passband of a first frequency band, a second filter having a passband of a second frequency band, the second frequency band being higher than the first frequency band, a third filter having a passband of a third frequency band, the third frequency band being higher than the second frequency band, and a sub-filter, connected to the second filter, configured to provide attenuation characteristics for the first frequency band, wherein the second filter comprises a plurality of parallel LC resonance circuits arranged between a ground and different nodes, from among a plurality of nodes between a first terminal and a second terminal, wherein an inductor is connected to a portion of the plurality of parallel LC resonance circuits.

A filter device is mounted on a module substrate and is shielded by a shield member. The filter device has first and second side surfaces opposed to each other. A ground terminal and signal terminals are formed on a bottom surface of the filter device. The shield member includes side wall portions facing the first and second side surfaces. The filter device includes plural LC parallel resonance circuits therein. The inductors of the LC parallel resonance circuits are arranged in parallel with the first side surface and the bottom surface. Each inductor extends upward from its end portion electrically connected to the ground terminal, extends from the first side surface toward the second side surface, and then extends toward the bottom surface. The gap between the first side surface and the corresponding side wall portion is smaller than that between the second side surface and the corresponding side wall portion.

An LC filter includes a multilayer body, plate electrodes, capacitor electrodes, and inductor vias. The capacitor electrodes each define a capacitor between the plate electrode and a corresponding one of the capacitor electrodes. A first inductor via is connected between a first capacitor electrode and a first plate electrode. A second inductor via is connected between a second capacitor electrode and the first plate electrode. A third inductor via is connected between a third capacitor electrode and the first plate electrode. A fourth capacitor electrode faces the first and second capacitor electrodes. A fifth capacitor electrode faces the second and third capacitor electrodes. A sixth capacitor electrode faces the first and third capacitor electrodes.