A multilayered filter device includes a multilayer stack, a band pass filter, a first band elimination filter, and a second band elimination filter. The band pass filter and the first and second band elimination filters are each constructed using the multilayer stack. The band pass filter includes a plurality of first resonators with open ends. Each band elimination filter includes a connection path, and a second resonator coupled to the connection path. The connection path includes an impedance transformer. The second resonator includes a conductor line constituting a distributed constant line.

A filter circuit may include a transmission line, a quarter wave resonator, and an electrical component coupled in series with the quarter wave resonator at a first end and to the transmission line at a second end. The electrical component may be have a frequency dependent impedance. The electrical component may be an inductor, a capacitor, or an inductor in series with a capacitor. In another aspect, a filter circuit may include a transmission line, a first quarter wave resonator coupled to a first electrical component and a second quarter wave resonator coupled to a second electrical component. Each of the first and second electrical components may be coupled to the transmission line in parallel with each other. The first and the second electrical components may have a frequency dependent impedance. The first electrical component may be the same as or different from the second electrical component.

A multilayered filter device includes a multilayer stack, a band pass filter, a first band elimination filter, and a second band elimination filter. The band pass filter and the first and second band elimination filters are each constructed using the multilayer stack. The band pass filter includes a plurality of first resonators with open ends. Each band elimination filter includes a connection path, and a second resonator coupled to the connection path. The connection path includes an impedance transformer. The second resonator includes a conductor line constituting a distributed constant line.

A power combiner/divider circuit can be structured having a base structure with the addition of an odd-mode capacitor and a low pass network at an end of the base structure or structured having a base structure with the addition of an inductor and a high pass network at an end of the base structure. The power combiner/divider circuit can be implemented as a port coupled to multiple ports with low pass networks or high pass networks arranged at the ends of paths to the multiple ports. In embodiments using low pass base structures or low pass networks coupled to the base structures, inductors in such low pass sections can be positively coupled on a pair-wise basis.

The invention relates to a tunable, silicon-based negative-resistance circuit (10, 30) and to an active filter (50) for E-band frequencies (60 to 90 GHz). A base of a transistor (11) is connected to an on-chip inductive transmission line (13) which has a length of approximately a quarter-wavelength at a frequency of 83.5 GHz. The transmission line connects a DC voltage source (14) to the base terminal of the transistor (11) in order to bias the base. Another DC voltage source (15) is connected to the collector of the transistor (11) to bias the transistor. A capacitor (16) operatively bypasses or decouples the voltage source (15) in order to shunt high frequencies or alternating current (AC) signals to ground. The emitter terminal of the transistor (11) is connected to ground through a resistor (18) to limit the collector current (l.sub.e). The circuit gives rise to improved quality factor of resonators.

A noise filter may include: a first conductive line extending between an input and an output terminal portion, wherein the first conductive line includes an input-side conductive line extending between the input terminal portion and a branch portion, and an output-side conductive line extending between the output terminal portion and the branch portion; a second conductive line connected to the branch portion of the first conductive line, wherein a capacitor is on the second conductive line; and a magnetic body surrounding at least a part of a circumference of at least a part of the first conductive line, wherein the magnetic body is configured to magnetically couple the input-side and the output-side conductive lines such that at least an equivalent series inductance of the capacitor and a parasitic inductance of the second conductive line are reduced by a mutual inductance between the input-side conductive line and the output-side conductive line.

A directional coupler includes a main line for transmitting a high frequency signal, a sub line electromagnetically coupled to the main line, a termination circuit for terminating one end portion of the sub line, and a variable filter that has an input terminal and an output terminal and the input terminal is connected to another end portion of the sub line. The variable filter is a filter unit circuit having one frequency band as a pass band or a stop band, and in the filter unit circuit, a variable passive element for shifting a frequency in the pass band or the stop band is disposed.

A power combiner/divider circuit can be structured having a base structure with the addition of an odd-mode capacitor and a low pass network at an end of the base structure or structured having a base structure with the addition of an inductor and a high pass network at an end of the base structure. The power combiner/divider circuit can be implemented as a port coupled to multiple ports with low pass networks or high pass networks arranged at the ends of paths to the multiple ports. In embodiments using low pass base structures or low pass networks coupled to the base structures, inductors in such low pass sections can be positively coupled on a pair-wise basis.

A filter includes: first and second parallel resonant circuits including a first capacitor, a first line, a second capacitor, and a second line that are shunt-connected to a series pathway connecting the input and output terminals; and first to sixth vias penetrating through a second dielectric layer on which the first and second lines are disposed, the first via connecting the first line to the series pathway, the second via connecting the first line to the ground terminal, the third via connecting the first line at a position between the first and second vias to the first connection line at a first position, the fourth via connecting the second line to the series pathway, the fifth via connecting the second line to the ground terminal, the sixth via connecting the second line at a position between the fourth and fifth vias to the first connection line at a second position.

A distributed LC filter structure is disclosed. The distributed LC filter structure provides simultaneously a distributed inductance and a distributed capacitance in the same structure. Accordingly, discrete passive elements are eliminated and high, homogenous integration is achieved. Interconnections between the distributed inductance and the distributed capacitance are tailored to leverage a parasitic inductance of the distributed capacitance to increase the overall inductance of the distributed LC filter structure. Similarly, the interconnections are tailored to leverage a parasitic capacitance resulting from the distributed inductance to add up with the distributed capacitance augmenting the overall capacitance of the structure.