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

Claim 2

A dielectric filter comprising: a plurality of end short-circuited strip line resonators respectively composed of a plurality of strip lines formed in parallel and close to each other on a surface of a first dielectric sheet so that each two adjacent strip line resonators are directly magnetically coupled to each other; an inter-resonator coupling capacitor electrode formed on a surface of a second dielectric sheet which is laminated on said first dielectric sheet in such a manner that said inter-resonator coupling capacitor electrode partially confronts all of the strip lines of said strip line resonators through said second dielectric sheet to constitute parallel plane capacitors; and first and second shield electrodes formed respectively on third and fourth dielectric sheets which are disposed so as to sandwich said first and second dielectric sheets therebetween; 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.

Claim 3

A dielectric filter according to claim 1, further comprising an additional dielectric sheet provided on an outermost one of the shield electrodes to protect the outermost shield electrode.

Claim 4

A dielectric filter according to claim 1, wherein said first through fourth dielectric sheets are laminated in the order of said third, first, second and fourth dielectric sheets with a first thick dielectric plate disposed between said third and first dielectric sheets and with a second thick dielectric plate disposed between said second and fourth dielectric sheets so that each of a distance between said shield electrode on said third dielectric sheet and said strip lines of said strip line resonators and a distance between said shield electrode on said fourth dielectric sheet and said inter-resonator coupling capacitor electrode is larger than a distance between said strip lines of said strip line resonators and said inter-resonator coupling capacitor electrode.

Claim 5

A dielectric filter according to claim 1, further comprising at least two external ground electrodes respectively formed on different side surfaces of a laminated body comprising said first through fourth dielectric sheets and connected to said shield electrodes.

Claim 6

A dielectric filter according to claim 1, further comprising at least two external ground electrodes respectively formed on opposite side surfaces of a laminated body comprising said first through fourth dielectric sheets and connected to said shield electrodes, a pattern of said external ground electrodes on one of said opposite side surfaces being different from a pattern of said external ground electrodes on the other of said opposite side surfaces.

Claim 7

A dielectric filter according to claim 1, 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 an external ground electrode formed on a side surface of a laminated body comprising said first through fourth dielectric sheets.

Claim 8

A dielectric filter according to claim 6, wherein another external ground electrode is formed on a side surface of the laminated body comprising said first through fourth dielectric sheets closer to open-circuited ends of said strip line resonators.

Claim 9

A dielectric filter according to claim 1, further comprising an external input terminal electrode and an external output terminal electrode which are formed on one side surface of a laminated body comprising said first through fourth dielectric sheets, and an external ground electrode formed between said external input and output terminal electrodes on said one side surface.

Claim 10

A dielectric filter according to claim 1, wherein said shield electrode on each of said third and fourth dielectric sheets is formed to leave a margin along the periphery of the corresponding dielectric sheet.

Claim 11

A dielectric filter according to claim 1, wherein said shield electrodes formed on said third and fourth dielectric sheets are of the same shape.

Claim 12

A dielectric filter according to claim 1, wherein a line width of a short-circuited end of a strip line of each of said strip line resonators is narrower than a line width of an open-circuited end of said strip line.

Claim 13

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.

Claim 14

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.

Claim 15

A dielectric filter according to claim 12, wherein said at least one first dielectric sheet disposed between said third and fourth dielectric sheets is a single dielectric sheet having said strip lines formed thereon, wherein said strip lines are formed from a single conductive layer formed on said single dielectric sheet.

Claim 16

A dielectric filter according to claim 12, wherein said at least one second dielectric sheet disposed between said third and fourth dielectric sheets is a single dielectric sheet having said inter-resonator coupling capacitor electrode formed thereon.

Claim 17

A dielectric filter according to claim 12, further comprising an additional dielectric sheet provided on an outermost one of the shield electrodes to protect the outermost shield electrode.

Claim 18

A dielectric filter according to claim 12, wherein said first through fourth dielectric sheets are laminated in the order of said third, first, second and fourth dielectric sheets with a first thick dielectric plate disposed between said third and first dielectric sheets and with a second thick dielectric plate disposed between said second and fourth dielectric sheets so that each of a distance between said shield electrode on said third dielectric sheet and said inter-resonator coupling capacitor electrode is larger than a distance between said strip lines of said strip line resonators and said inter-resonator coupling capacitor electrode.

Claim 19

A dielectric filter according to claim 12, further comprising at least two external ground electrodes respectively formed on different side surfaces of a laminated body comprising said first through fourth dielectric sheets and connected to said shield electrodes.

Claim 20

A dielectric filter according to claim 12, further comprising at least two external ground electrodes respectively formed on opposite side surfaces of a laminated body comprising said first through fourth dielectric sheets and connected to said shield electrodes, a pattern of said external ground electrodes on one of said opposite side surfaces being different from a pattern of said external ground electrodes on the other of said opposite side surfaces.

Claim 21

A dielectric filter according to claim 12, 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 an external ground electrode formed on a side surface of a laminated body comprising said first through fourth dielectric sheets.

Claim 22

A dielectric filter according to claim 19, wherein another external ground electrode is formed on a side surface of the laminated body comprising said first through fourth dielectric sheets closer to open-circuited ends of said strip line resonators.

Claim 23

A dielectric filter according to claim 12, further comprising an external input terminal electrode and an external output terminal electrode which are formed on one side surface of a laminated body comprising said first through fourth dielectric sheets, and an external ground electrode formed between said external input and output terminal electrodes on said one side surface.

Claim 24

A dielectric filter according to claim 12, wherein said shield electrode on each of said third and fourth dielectric sheets is formed to leave a margin along the periphery of its corresponding dielectric sheet.

Claim 25

A dielectric filter according to claim 12, wherein said shield electrodes formed on said third and fourth dielectric sheets are of the same shape.

Claim 26

A dielectric filter according to claim 12, wherein a line width of a short-circuited end of a strip line of each said strip line resonators is narrower than a line width of an open-circuited end of said strip line.

Claim 27

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.

Claim 28

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.

Claim 29

A dielectric filter according to claim 25, further comprising a second capacitor electrode formed on said first surface of said second dielectric sheet so as to partially confront said strip lines of said strip line resonators to thereby constitute second parallel plane capacitors, said second capacitor electrode is connected to a ground.

Claim 30

A dielectric filter according to claim 25, further comprising a third capacitor electrode formed on said first surface of said second dielectric sheet so as to partially confront one of said strip lines of said strip line resonators to thereby constitute a third parallel plane capacitor, and a fourth capacitor electrode formed on said first surface of said second dielectric sheet so as to partially confront another of said strip lines of said strip line resonators to thereby constitute a fourth parallel plane capacitor, said third and fourth capacitor electrodes are respectively connected to input and output terminal electrodes formed on a side surface of a laminated body comprising said first through fifth dielectric sheets and said first and second dielectric plates.

Claim 31

A dielectric filter according to claim 25, 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 ground electrode formed on a side surface of a laminated body comprising said first through fifth dielectric sheets and said first and second dielectric plates.

Claim 32

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.

Claim 33

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.

Claim 34

A dielectric filter according to claim 29, further comprising a second capacitor electrode formed on said first surface of said second dielectric sheet so as to partially confront said strip lines of said two strip line resonators to thereby constitute second parallel plane capacitors, said second capacitor electrode being connected to a ground.

Claim 35

A dielectric filter according to claim 29, further comprising a third capacitor electrode formed on said first surface of said second dielectric sheet so as to partially confront one of said strip lines of said two strip line resonators to thereby constitute a third parallel plane capacitor, and a fourth capacitor electrode formed on said first surface of said second dielectric sheet so as to partially confront another of said strip lines of said two strip line resonators to thereby constitute a fourth parallel plane capacitor, said third and fourth capacitor electrodes being respectively connected to input and output terminal electrodes formed on a side surface of a laminated body comprising said first through fifth dielectric sheets and said first and second dielectric plates.

Claim 36

A dielectric filter according to claim 29, wherein short-circuited ends of said two strip line resonators extend to a same side surface of said first dielectric sheet and are connected to an external ground electrode formed on a side surface of a laminated body comprising said first through fifth dielectric sheets and said first and second dielectric plates.

Claim 37

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.

Claim 38

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.

Claim 39

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.

Claim 40

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.