LC composite part with no adverse magnetic field in the capacitor

An LC composite part, comprising:

• a substrate including a magnetic material and a dielectric material;
• a first and a second terminal electrode formed on end faces of the substrate;
• ground electrodes formed on side faces of the substrate;
• inductors formed at an inside of the substrate having conductor films formed in a spiral shape extending over a plurality of layers arranged between the first terminal electrode and the second terminal electrode, said inductors having substantially parallel axes;
• and
• at least two capacitors formed at said inside of the substrate and arranged between intermediate points of the inductors different from each other and the ground electrodes, said intermediate points being defined as points on a line extending perpendicular to said parallel axes.

An LC composite part, comprising:

• a substrate including a magnetic material and a dielectric material;
• inductors and capacitors formed at an inside of the substrate constituting a low pass LC filter circuit of at least one of a T-type, a .pi.-type and a multi-stage type;
• and
• wherein when a cut off frequency of the LC circuit is designated by a notation fc, an inductance of at least one of said inductors is designated by a notation L, and a capacitance of at least one residual capacitor connected in parallel to said at least one of said inductors is designated by a notation C, the at least one residual capacitor is provided with a capacitance satisfying the following equation:
• log(fc)+0.6.ltoreq.log{1/[2(2.pi..sqroot.(LC))]}.ltoreq.log(fc)+1.5.

An LC filter comprising:

• a base substrate;
• and
• a plurality of layers formed on said base substrate,
• wherein at least one of said plurality of layers comprises at least one inductor and at least one capacitor, said at least one inductor having two spiral structures including substantially parallel axes and being arranged and connected to each other so that magnetic fluxes at insides of said two spiral structures are parallel and in mutually reverse directions,
• wherein said at least one capacitor is positioned between said two spiral structures at a line extending perpendicular to said parallel axes.

A method of manufacturing an LC filter, comprising the steps of:

• forming at least one layer on a base substrate;
• forming at least one inductor having two spiral structures including substantially parallel axes and being arranged so that magnetic fluxes at insides of said two spiral structures are parallel and in mutually reverse directions on said at least one layer;
• and
• forming at least one plane plate capacitor on said at least one layer at a position between said two spiral structures defined by a line extending perpendicular to said parallel axes.

An LC filter, comprising:

• means for forming at least one layer on a base substrate;
• means for forming at least one inductor having two spiral structures including substantially parallel axes and being arranged so that magnetic fluxes at insides of said two spiral structures are parallel and in mutually reverse directions on said at least one layer;
• and
• means for forming at least one plane plate capacitor on said at least one layer at a position between said two spiral structures defined by a line extending perpendicular to said parallel axes.