LAMINATED BAND PASS FILTER

• US 20100171568A1
• Filed: 03/23/2010
• Published: 07/08/2010
• Est. Priority Date: 09/27/2007
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: TANIGUCHI, Tetsuo
• Granted Patent: US 8,212,633 B2
• Time in Patent Office: Days
• US Class Current: 333/176
• CPC Class Codes: H03H 2001/0085 Multilayer, e.g. LTCC, HTCC, green sheets inside PCB filters H05K
• CPC Class Codes: H03H 7/0115 comprising only inductors and capacitors H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence
• CPC Class Codes: H03H 7/09 Filters comprising mutual inductance
• CPC Class Codes: H03H 7/1708 Comprising bridging elements, i.e. elements in a series path without own reference to ground and spanning branching nodes of another series path H03H7/07 takes precedence
• CPC Class Codes: H03H 7/1775 Parallel LC in shunt or branch path H03H7/1791 takes precedence

Abstract

A small low-loss laminated band pass filter attains steep attenuation from a pass band to out-of pass band and reduced ripple in the band. Capacitances are generated between a ground electrode on a ground electrode forming layer and capacitor electrodes on a capacitor electrode forming layer, a plurality of inductor electrodes are defined by via electrodes and the line electrodes, and portions of respective loop surfaces of the inductor electrodes overlap with one another when viewed from a direction of arrangement of the inductor electrodes. Furthermore, a line electrode is arranged on a first line electrode forming layer and line electrodes are arranged on a second line electrode forming layer.

Claims

1. A laminated band pass filter comprising:

a laminated body including a plurality of dielectric layers and a plurality of electrode layers laminated together;

a plurality of LC parallel resonators configured by connecting a ground electrode and capacitor electrodes which are arranged on any of the electrode layers to inductor electrodes, each of the inductor electrodes extending from a connection point between one of the LC parallel resonator and a corresponding one of the capacitor electrodes through a corresponding one of the electrode layers which is different from the electrode layer including the capacitor electrodes to a connection point between the LC parallel resonator and the ground electrode, and each of the inductor electrodes being arranged in a loop shape when viewed from a perpendicular or substantially perpendicular direction relative to a lamination direction of the laminated body;

wherein

the inductor electrodes of at least two of the LC parallel resonators pass different electrode layers.

2. The laminated band pass filter according to claim 1, wherein the two LC parallel resonators including the inductor electrodes passing the different electrode layers are arranged in an arrangement direction that is perpendicular or substantially perpendicular to the lamination direction of the dielectric layers and the electrode layers, and the inductor electrodes of the two LC parallel resonators are arranged such that the loops overlap with each other when viewed from the arrangement direction.

3. The laminated band pass filter according to claim 2, wherein directions of the loops of the inductor electrodes of the two LC parallel resonators are opposite to each other.

4. The laminated band pass filter according to claim 2, wherein at least one of the two LC parallel resonators is a resonator of an input stage or an output stage.

5. The laminated band pass filter according to claim 1, wherein each of the two LC parallel resonators including the respective inductor electrodes passing the different electrode layers is configured such that a corresponding one of the inductor electrodes includes via electrodes extending in the lamination direction of the dielectric layers and the electrode layers and a line electrode passing a corresponding one of the electrode layers.

6. The laminated band pass filter according to claim 5, wherein the line electrodes of the two LC parallel resonators are arranged so as to overlap with each other in a loop shape when viewed from the lamination direction.

7. The laminated band pass filter according to claim 5, wherein at least one of the line electrodes of the two LC parallel resonators has a meander-line shape or a U-shape.

8. The laminated band pass filter according to claim 5, wherein at least one of an input electrode connected to the LC parallel resonator of the input stage and an output electrode connected to the LC parallel resonator of the output stage is connected to one of the via electrodes between a corresponding one of the line electrodes and a corresponding one of the capacitor electrodes.

9. The laminated band pass filter according to claim 2, further comprising:

a capacitor electrode arranged to provide skip coupling and including one terminal which faces one of the capacitor electrodes of the two LC parallel resonators and the other terminal which faces the other of the capacitor electrodes of the two LC parallel resonators.

10. The laminated band pass filter according to claim 2, wherein the capacitor electrode of the LC parallel resonator of the input stage and the capacitor electrode of the LC parallel resonator of the output stage are adjacent to each other in the same electrode layer.