Dielectric filter having inter-resonator coupling including both magnetic and electric coupling

A dielectric filter comprising:

• at least one first dielectric sheet having formed thereon a plurality of end short-circuited strip line resonators respectively composed of a plurality of strip lines which are formed in parallel and close to each other so that each two adjacent strip line resonators are directly magnetically coupled to each other;
• at least one second dielectric sheet having at least one inter-resonator coupling capacitor electrode formed thereon, said second dielectric sheet being laminated on said first dielectric sheet;
• and
• third and fourth dielectric sheets each having a shield electrode formed thereon;
• said first through fourth dielectric sheets being laminated such that said inter-resonator coupling capacitor electrode partially confronts at least two of said strip lines of said strip line resonators through said second dielectric sheet to constitute a parallel plane capacitor and such that said third and fourth dielectric sheets sandwich said first and second dielectric sheets therebetween so as to shield said strip line resonators and said parallel plane capacitor with said shield electrodes;
• said strip line resonators being electrically coupled to each other through said parallel plane capacitors whereby an inter-resonator coupling is effected in combination with said magnetic coupling and electric coupling.

A dielectric filter comprising:

• a first dielectric sheet having opposite first and second surfaces;
• a plurality of end short-circuited strip line resonators respectively composed of a plurality of strip lines each having a length of about quarter-wavelength formed in parallel and close to each other on said first surface of said first dielectric sheet so that each two adjacent said strip line resonators are directly magnetically coupled to each other;
• a second dielectric sheet having opposite first and second surfaces and laminated on said first dielectric sheet such that said second surface of said second dielectric sheet contacts said first surface of said first dielectric sheet;
• a capacitor electrode formed on said first surface of said second dielectric sheet in such a manner that said capacitor electrode partially confronts all of the strip lines of said strip line resonators through said second dielectric sheet to constitute parallel plane capacitors so that said strip line resonators are electrically coupled to each other through said parallel plane capacitors whereby an inter-resonator coupling is effected in combination with said magnetic coupling and electric coupling;
• a third dielectric sheet having opposite first and second surfaces;
• a first shield electrode formed on said first surface of said third dielectric sheet, said third dielectric sheet being laminated on said second surface of said first dielectric sheet via a first dielectric plate interposed therebetween so that said first surface of said third dielectric sheet confronts said second surface of said first dielectric sheet;
• a fourth dielectric sheet having opposite first and second surfaces;
• a second shield electrode formed on said first surface of said fourth dielectric sheet, said fourth dielectric sheet being laminated on said first surface of said second dielectric sheet via a second dielectric plate interposed therebetween so that said second surface of said fourth dielectric sheet confronts said first surface of said second dielectric sheet;
• and
• a fifth dielectric sheet laminated on said first surface of said fourth dielectric sheet to protect said second shield electrode.

A dielectric filter comprising:

• a first dielectric sheet having opposite first and second surfaces;
• two end short-circuited strip line resonators respectively composed of two strip lines each having a length of about quarter-wavelength formed in parallel and close to each other on said first surface of said first dielectric sheet so that said two strip line resonators are directly magnetically coupled to each other;
• a second dielectric sheet having opposite first and second surfaces and laminated on said first dielectric sheet such that said second surface of said second dielectric sheet contacts said first surface of said first dielectric sheet;
• a capacitor electrode formed on said first surface of said second dielectric sheet in such a manner that said capacitor electrode partially confronts the strip lines of said two strip line resonators through said second dielectric sheet to constitute parallel plane capacitors so that said strip line resonators are electrically coupled to each other through said parallel plane capacitors whereby an inter-resonator coupling is effected in combination with said magnetic coupling and electric coupling;
• a third dielectric sheet having opposite first and second surfaces;
• a first shield electrode formed on said first surface of said third dielectric sheet, said third dielectric sheet being laminated on said second surface of said first dielectric sheet via a first dielectric plate interposed therebetween so that said first surface of said third dielectric sheet confronts said second surface of said first dielectric sheet;
• a fourth dielectric sheet having opposite first and second surfaces;
• a second shield electrode formed on said first surface of said fourth dielectric sheet, said fourth dielectric sheet being laminated on said first surface of said second dielectric sheet via a second dielectric plate interposed therebetween so that said second surface of said fourth dielectric sheet confronts said first surface of said second dielectric sheet;
• and
• a fifth dielectric sheet laminated on said first surface of said fourth dielectric sheet to protect said second shield electrode.

A dielectric filter comprising:

• at least one first dielectric sheet having formed thereon a plurality of end short-circuited strip line resonators respectively composed of a plurality of strip lines where are formed in parallel and close to each other so that each two adjacent strip line resonators are directly magnetically coupled to each other, wherein short-circuited ends of all of said strip line resonators extend to a same side surface of said first dielectric sheet and are connected to a first external ground electrode;
• at least one second dielectric sheet having at least one loading capacitor electrode formed thereon, said second dielectric sheet being laminated on said first dielectric sheet and said loading capacitor electrode being connected to a second external ground electrode;
• and
• third and fourth dielectric sheets each having a shield electrode formed thereon, said shield electrodes being connected to said first and second external ground electrodes;
• said first through fourth dielectric sheets being laminated such that said loading capacitor electrode partially confronts at least one of said strip lines of said strip line resonators through said second dielectric sheet to constitute a parallel plane capacitor and such that said third and fourth dielectric sheets sandwich said first and second dielectric sheets therebetween so as to shield said strip line resonators and said parallel plane capacitor with said shield electrodes;
• said first and second external ground electrodes being formed on different side surfaces of a laminated body comprising said first through fourth dielectric sheets.

A dielectric filter comprising:

• at least one first dielectric sheet having formed thereon a plurality of end short-circuited strip line resonators respectively composed of a plurality of strip lines which are formed in parallel and close to each other so that each two adjacent strip line resonators are directly magnetically coupled to each other, wherein short-circuited ends of all of said strip line resonators extend to a same side surface of said first dielectric sheet and are connected to a first external ground electrode;
• at least one second dielectric sheet laminated on said first dielectric sheet;
• a first capacitor electrode formed on said second dielectric sheet so as to partially confront one of said end short-circuited strip line resonators through said second dielectric sheet to thereby constitute a first parallel plane capacitor;
• a second capacitor electrode formed on said second dielectric sheet so as to partially confront another of said end short-circuited strip line resonators through said second dielectric sheet to thereby constitute a second parallel plane capacitor;
• third and fourth dielectric sheets each having a shield electrode formed thereon, said first through fourth dielectric sheets being laminated such that said third and fourth dielectric sheets sandwich said first and second dielectric sheets therebetween so as to shield said strip line resonators and said parallel plane capacitors with said shield electrodes;
• and
• a second external ground electrode formed on another side surface of the laminated body comprising said first through fourth dielectric sheets closer to open-ends of said strip line resonators, said shield electrodes being connected to said first and second external ground electrodes;
• said first and second capacitor electrodes being respectively connected to external input and output terminal electrodes formed on a side surface of a laminated body comprising said first through fourth dielectric sheets.