A filter configuration including a substrate, a primary microstrip line and a first defected ground structure is disclosed. The substrate has a first face and a second face. The second face is a ground face. The primary microstrip line is arranged on the first face and extends in a first direction.

The first defected ground structure is arranged on the second face. The first defected ground structure includes a first section, a first circular section, a second section, a second circular section and a third section that are connected to each other in sequence in a second direction perpendicular to the first direction. The second section is covered by the primary microstrip line in a vertical direction perpendicular to the first and second faces. The primary microstrip line has a width equal to a minimum length of the second section. As such, the filtering effect can be improved.

A step impedance resonator filter including a first resonator and a second resonator is disclosed. The first resonator includes a first coupled line and a first tapped line connected to the first coupled line. The second resonator includes a second coupled line and a second tapped line connected to the second coupled line. The second coupled line is coupled with the first coupled line. The first tapped line has a first central line which is spaced from an end face of the first coupled line at a first distance. The second tapped line has a second central line which is spaced from an end face of the second coupled line at a second distance. The first distance is larger than the second distance. As such, the performance of the step impedance resonator filter can be improved.

A high-frequency signal line includes a dielectric body including a first dielectric layer and one or more other dielectric layers laminated together. A first signal line is provided on a first main surface, which is a main surface located on one side in a direction of lamination, of the first dielectric layer. A second signal line is provided on a second main surface, which is a main surface located on another side in the lamination direction, of the first dielectric layer so as to face the first signal line via the first dielectric layer. The second signal line is electrically connected to the first signal line. A first ground conductor is located on one side in the lamination direction than the first signal line. A second ground conductor is located on another side in the lamination direction than the second signal line.

A flexible high-frequency signal transmission line includes a dielectric body including laminated flexible dielectric layers. A signal line is provided in the dielectric body. A grounding conductor is arranged in the dielectric body to be opposed to the signal line via one of the dielectric layers. The grounding conductor is of a ladder structure including a plurality of openings and a plurality of bridges arranged alternately along the signal line. A characteristic impedance of the signal line changes between two adjacent ones of the plurality of bridges such that the characteristic impedance of the signal line rises from a minimum value to an intermediate value and to a maximum value and falls from the maximum value to the intermediate value and to the minimum value in this order.

A flat cable high-frequency filter includes a dielectric substrate extending in a transmission direction of a high-frequency signal. The dielectric substrate includes dielectric layers stacked on each other. Elongated conductor patterns are provided on a flat surface of one dielectric layer which faces another dielectric layer. The conductor patterns are as wide as possible in the dielectric substrate in accordance with a desired inductance. A capacitive coupling conductor pattern opposes one conductor pattern by a predetermined area with a dielectric layer therebetween. By using a connecting conductor, the capacitive coupling conductor pattern is connected to the conductor pattern which does not oppose the capacitive coupling conductor pattern.

A high-frequency signal transmission line includes a dielectric body including dielectric layers stacked together, a linear signal line provided in the dielectric body, a first ground conductor provided at the dielectric body, at a first side of the signal line in a stacking direction so as to face the signal line, and a subsidiary member provided at the dielectric body, at a second side of the signal line in the stacking direction so as to face a central portion of the signal line in a line-width direction. In a sectional view along a plane perpendicular or substantially perpendicular to an extending direction of the signal line, the signal line is curved such that side portions of the signal line in the line-width direction are farther away from the first ground conductor than a central portion of the signal line in the line-width direction.

The present invention related to self-limiting filters, arrays of such filters, and methods thereof. In particular embodiments, the filters include a metal transition film (e.g., a VO.sub.2 film) capable of undergoing a phase transition that modifies the film's resistivity. Arrays of such filters could allow for band-selective interferer rejection, while permitting transmission of non-interferer signals.

A high frequency band pass filter with a coupled surface mount transition is provided, including a filter substrate, circuit connection elements defining input and an output elements provided on a surface of the filter substrate, electronic filter components provided on the first surface of the filter substrate, and impedance matching structures provided on the first surface of the filter substrate between the electronic filter components and the respective input and output elements. Signal connection structures are provided on an opposed surface of the filter substrate, in locations that positionally correspond to respective positions of the input and output elements. The respective signal connection elements are capacitively coupled, through a thickness direction of the filter substrate, to a respective one of the input and output elements on the opposed surface of the filter substrate without the presence of any vertical conductive structures within the filter substrate at the input and the output elements.

A flat cable high-frequency filter includes a dielectric substrate extending in a transmission direction of a high-frequency signal. The dielectric substrate includes dielectric layers stacked on each other. Elongated conductor patterns are provided on a flat surface of one dielectric layer which faces another dielectric layer. The conductor patterns are as wide as possible in the dielectric substrate in accordance with a desired inductance. A capacitive coupling conductor pattern opposes one conductor pattern by a predetermined area with a dielectric layer therebetween. By using a connecting conductor, the capacitive coupling conductor pattern is connected to the conductor pattern which does not oppose the capacitive coupling conductor pattern.

Chipless RFID tags and a tag system are provided, wherein the stepped impedance higher-order mode resonator includes two sets of composite transmission lines each set having an equal line length and including a plurality of transmission lines each having a plurality of specific levels to which the transmission line characteristic impedance is assigned, the two sets of composite transmission lines each connected in series, the sets being connected at the center to form an electrically symmetrical configuration and wherein the chipless RFID tags and the tag system allow each of the codes to be assigned to each of the structures of the stepped impedance higher-order mode resonator, and allow each of those codes to be identified by detecting each of the combinations of the higher-order mode resonance frequencies that may be produced from each the structures of the resonator that corresponds to each of the codes that have been assigned.