Multi-layer band-pass filter

Claim 2

A multi-layer band-pass filter comprising: an unbalanced input for receiving unbalanced signals; a first balanced output and a second balanced output for outputting balanced signals; a band-pass filter section provided between the unbalanced input and the first and second balanced outputs and incorporating a plurality of resonators each of which is made up of a TEM line; and a multi-layer substrate used for integrating the resonators, wherein the band-pass filter section incorporates, as the resonators, an input resonator to which the unbalanced input is connected, and a half-wave resonator for balanced output to which the first and second balanced outputs are connected, the half-wave resonator for balanced output being made up of a half-wave resonator having open-circuited ends, the multi-layer band-pass filter further comprising a capacitor made up of part of the multi-layer substrate and provided in at least one of a location between the unbalanced input and the input resonator and a location between each of the first and second balanced outputs and the half-wave resonator for balanced output, the capacitor including: a first conductor layer connected to one of the input resonator and the half-wave resonator for balanced output via a through hole; and a second conductor layer opposed to the first conductor layer and connected to one of the unbalanced input, the first balanced output and the second balanced output.

Claim 3

The multi-layer band-pass filter according to claim 1 , further comprising first and second output capacitors as the capacitor provided between the half-wave resonator for balanced output and the first and second balanced outputs, respectively, wherein the first balanced output is connected through the first output capacitor to an end of a length of the half-wave resonator for balanced output, and the second balanced output is connected through the second output capacitor to the other end of the length of the half-wave resonator for balanced output.

Claim 4

The multi-layer band-pass filter according to claim 2 , wherein the first output capacitor and the second output capacitor have different capacitances.

Claim 5

The multi-layer band-pass filter according to claim 1 , wherein the band-pass filter section incorporates at least one half-wave resonator having open-circuited ends, the open-circuited ends being connected to each other through a capacitor.

Claim 6

A multi-layer band-pass filter comprising: an unbalanced input for receiving unbalanced signals; a first balanced output and a second balanced output for outputting balanced signals; a band-pass filter section provided between the unbalanced input and the first and second balanced outputs and incorporating a plurality of resonators each of which is made up of a TEM line; and a multi-layer substrate used for integrating the resonators, wherein: the band-pass filter section incorporates, as the resonators, a half-wave resonator for balanced output that is made up of a half-wave resonator having open-circuited ends, and quarter-wave resonators for balanced output each of which is made up of a quarter-wave resonator, the quarter-wave resonators for balanced output being provided to form one or more stages each of which consists of a pair of the quarter-wave resonators for balanced output, and being disposed between the half-wave resonator for balanced output and the first and second balanced outputs; and the first and second balanced outputs are connected to a pair of the quarter-wave resonators for balanced output of a final stage, respectively, the multi-layer band-pass filter further comprising a capacitor made up of part of the multi-layer substrate and provided in at least one of a location between the unbalanced input and the resonator connected thereto and a location between each of the first and second balanced outputs and the pair of the quarter-wave resonators of the final stage, wherein: the pair of the quarter-wave resonators of the final stage are only provided as the quarter-wave resonators for balanced output; one of the pair of the quarter-wave resonators of the final stage is coupled to one of half portions of the half-wave resonator for balanced output; and the other one of the pair of the quarter-wave resonators of the final stage is coupled to the other one of the half portions of the half-wave resonator for balanced output, the half portions of the half-wave resonator for balanced output being taken along a length thereof.

Claim 7

A multi-layer band-pass filter comprising: an unbalanced input for receiving unbalanced signals; a first balanced output and a second balanced output for outputting balanced signals; a band-pass filter section provided between the unbalanced input and the first and second balanced outputs and incorporating a plurality of resonators each of which is made up of a TEM line; and a multi-layer substrate used for integrating the resonators, wherein: the band-pass filter section incorporates, as the resonators, a half-wave resonator for balanced output that is made up of a half-wave resonator having open-circuited ends, and quarter-wave resonators for balanced output each of which is made up of a quarter-wave resonator, the quarter-wave resonators for balanced output being provided to form one or more stages each of which consists of a pair of the quarter-wave resonators for balanced output, and being disposed between the half-wave resonator for balanced output and the first and second balanced outputs; and the first and second balanced outputs are connected to a pair of the quarter-wave resonators for balanced output of a final stage, respectively, the multi-layer band-pass filter further comprising a capacitor made up of part of the multi-layer substrate and provided in at least one of a location between the unbalanced input and the resonator connected thereto and a location between each of the first and second balanced outputs and the pair of the quarter-wave resonators of the final stage, wherein: the pair of the quarter-wave resonators of the final stage are only provided as the quarter-wave resonators for balanced output; one of the pair of the quarter-wave resonators of the final stage is coupled to one of half portions of the half-wave resonator for balanced output; and the other one of the pair of the quarter-wave resonators of the final stage is coupled to the other one of the half portions of the half-wave resonator for balanced output, the half portions of the half-wave resonator for balanced output being taken along a length thereof.

Claim 8

The multi-layer band-pass filter according to claim 5 , wherein the pair of the quarter-wave resonators of the final stage are coupled to the half-wave resonator by means of a single coupling method.

Claim 9

The multi-layer band-pass filter according to claim 5 , wherein one of the pair of the quarter-wave resonators of the final stage is coupled only to one of the half portions of the half-wave resonator, and the other one of the pair of the quarter-wave resonators of the final stage is coupled only to the other one of the half portions of the half-wave resonator.

Claim 10

A multi-layer band-pass filter comprising: an unbalanced input for receiving unbalanced signals; a first balanced output and a second balanced output for outputting balanced signals; a band-pass filter section provided between the unbalanced input and the first and second balanced outputs and incorporating a plurality of resonators each of which is made up of a TEM line; and a multi-layer substrate used for integrating the resonators, wherein: the band-pass filter section incorporates, as the resonators, a half-wave resonator for balanced output that is made up of a half-wave resonator having open-circuited ends, and quarter-wave resonators for balanced output each of which is made up of a quarter-wave resonator, the quarter-wave resonators for balanced output being provided to form one or more stages each of which consists of a pair of the quarter-wave resonators for balanced output, and being disposed between the half-wave resonator for balanced output and the first and second balanced outputs; and the first and second balanced outputs are connected to a pair of the quarter-wave resonators for balanced output of a final stage, respectively, the multi-layer band-pass filter further comprising a capacitor made up of part of the multi-layer substrate and provided in at least one of a location between the unbalanced input and the resonator connected thereto and a location between each of the first and second balanced outputs and the pair of the quarter-wave resonators of the final stage, wherein: a plurality of stages of the quarter-wave resonators for balanced output are provided; one of a pair of the quarter-wave resonators of a first stage closest to the half-wave resonator for balanced output is coupled to one of half portions of the half-wave resonator for balanced output; and the other one of the pair of the quarter-wave resonators of the first stage is coupled to the other one of the half portions of the half-wave resonator for balanced output, the half portions of the half-wave resonator for balanced output being taken along a length thereof.

Claim 11

A multi-layer band-pass filter comprising: an unbalanced input for receiving unbalanced signals; a first balanced output and a second balanced output for outputting balanced signals; a band-pass filter section provided between the unbalanced input and the first and second balanced outputs and incorporating a plurality of resonators each of which is made up of a TEM line; and a multi-layer substrate used for integrating the resonators, wherein: the band-pass filter section incorporates, as the resonators, a half-wave resonator for balanced output that is made up of a half-wave resonator having open-circuited ends, and quarter-wave resonators for balanced output each of which is made up of a quarter-wave resonator, the quarter-wave resonators for balanced output being provided to form one or more stages each of which consists of a pair of the quarter-wave resonators for balanced output, and being disposed between the half-wave resonator for balanced output and the first and second balanced outputs; and the first and second balanced outputs are connected to a pair of the quarter-wave resonators for balanced output of a final stage, respectively, the multi-layer band-pass filter further comprising a capacitor made up of part of the multi-layer substrate and provided in at least one of a location between the unbalanced input and the resonator connected thereto and a location between each of the first and second balanced outputs and the pair of the quarter-wave resonators of the final stage, wherein: a plurality of stages of the quarter-wave resonators for balanced output are provided; one of a pair of the quarter-wave resonators of a first stage closest to the half-wave resonator for balanced output is coupled to one of half portions of the half-wave resonator for balanced output; and the other one of the pair of the quarter-wave resonators of the first stage is coupled to the other one of the half portions of the half-wave resonator for balanced output, the half portions of the half-wave resonator for balanced output being taken along a length thereof.

Claim 12

The multi-layer band-pass filter according to claim 8 , wherein the pair of the quarter-wave resonators of the first stage are coupled to the half-wave resonator by means of a single coupling method.

Claim 13

The multi-layer band-pass filter according to claim 8 , wherein one of the pair of the quarter-wave resonators of the first stage is coupled only to one of the half portions of the half-wave resonator, and the other one of the pair of the quarter-wave resonators of the first stage is coupled only to the other one of the half portions of the half-wave resonator.

Claim 14

The multi-layer band-pass filter according to claim 8 , wherein a pair of the quarter-wave resonators of each of the stages are coupled to a pair of the quarter-wave resonators of a previous or next stage by means of a single coupling method.

Claim 15

A multi-layer band-pass filter comprising: an unbalanced input for receiving unbalanced signals; a first balanced output and a second balanced output for outputting balanced signals; a band-pass filter section provided between the unbalanced input and the first and second balanced outputs and incorporating a plurality of resonators each of which is made up of a TEM line; and a multi-layer substrate used for integrating the resonators, wherein: the band-pass filter section incorporates, as the resonators, a half-wave resonator for balanced output that is made up of a half-wave resonator having open-circuited ends, and quarter-wave resonators for balanced output each of which is made up of a quarter-wave resonator, the quarter-wave resonators for balanced output being provided to form one or more stages each of which consists of a pair of the quarter-wave resonators for balanced output, and being disposed between the half-wave resonator for balanced output and the first and second balanced outputs; and the first and second balanced outputs are connected to a pair of the quarter-wave resonators for balanced output of a final stage, respectively, the multi-layer band-pass filter further comprising a capacitor made up of part of the multi-layer substrate and provided in at least one of a location between the unbalanced input and the resonator connected thereto and a location between each of the first and second balanced outputs and the pair of the quarter-wave resonators of the final stage, wherein the band-pass filter section incorporates at least one half-wave resonator having open-circuited ends, the open-circuited ends being connected to each other through a capacitor.

Claim 16

A multi-layer band-pass filter comprising: an unbalanced input for receiving unbalanced signals; a first balanced output and a second balanced output for outputting balanced signals; a band-pass filter section provided between the unbalanced input and the first and second balanced outputs and incorporating a plurality of resonators each of which is made up of a TEM line; and a multi-layer substrate used for integrating the resonators, wherein: the band-pass filter section incorporates, as the resonators, a half-wave resonator for balanced output that is made up of a half-wave resonator having open-circuited ends, and quarter-wave resonators for balanced output each of which is made up of a quarter-wave resonator, the quarter-wave resonators for balanced output being provided to form one or more stages each of which consists of a pair of the quarter-wave resonators for balanced output, and being disposed between the half-wave resonator for balanced output and the first and second balanced outputs; and the first and second balanced outputs are connected to a pair of the quarter-wave resonators for balanced output of a final stage, respectively, the multi-layer band-pass filter further comprising a capacitor made up of part of the multi-layer substrate and provided in at least one of a location between the unbalanced input and the resonator connected thereto and a location between each of the first and second balanced outputs and the pair of the quarter-wave resonators of the final stage, wherein the band-pass filter section incorporates at least one half-wave resonator having open-circuited ends, the open-circuited ends being connected to each other through a capacitor.

Claim 17

A multi-layer band-pass filter comprising: an unbalanced input for receiving unbalanced signals; a first balanced output and a second balanced output for outputting balanced signals; a band-pass filter section provided between the unbalanced input and the first and second balanced outputs and incorporating a plurality of resonators each of which is made up of a TEM line; and a multi-layer substrate used for integrating the resonators, wherein the band-pass filter section incorporates, as the resonators, an input resonator to which the unbalanced input is connected, and a half-wave resonator for balanced output to which the first and second balanced outputs are connected, the half-wave resonator for balanced output being made up of a half-wave resonator having open-circuited ends, the multi-layer band-pass filter further comprising first and second output capacitors made up of part of the multi-layer substrate and provided between the half-wave resonator for balanced output and the first and second balanced outputs, respectively, wherein: the first balanced output is connected through the first output capacitor to an end of a length of the half-wave resonator for balanced output, and the second balanced output is connected through the second output capacitor to the other end of the length of the half-wave resonator for balanced output; and the first output capacitor and the second output capacitor have different capacitances.

Claim 18

A multi-layer band-pass filter comprising: an unbalanced input for receiving unbalanced signals; a first balanced output and a second balanced output for outputting balanced signals; a band-pass filter section provided between the unbalanced input and the first and second balanced outputs and incorporating a plurality of resonators each of which is made up of a TEM line; and a multi-layer substrate used for integrating the resonators, wherein the band-pass filter section incorporates, as the resonators, an input resonator to which the unbalanced input is connected, and a half-wave resonator for balanced output to which the first and second balanced outputs are connected, the half-wave resonator for balanced output being made up of a half-wave resonator having open-circuited ends, the multi-layer band-pass filter further comprising first and second output capacitors made up of part of the multi-layer substrate and provided between the half-wave resonator for balanced output and the first and second balanced outputs, respectively, wherein: the first balanced output is connected through the first output capacitor to an end of a length of the half-wave resonator for balanced output, and the second balanced output is connected through the second output capacitor to the other end of the length of the half-wave resonator for balanced output; and the first output capacitor and the second output capacitor have different capacitances.

Claim 19

A multi-layer band-pass filter comprising: an unbalanced input for receiving unbalanced signals; a first balanced output and a second balanced output for outputting balanced signals; a band-pass filter section provided between the unbalanced input and the first and second balanced outputs and incorporating a plurality of resonators each of which is made up of a TEM line; and a multi-layer substrate used for integrating the resonators, wherein the band-pass filter section incorporates, as the resonators, an input resonator to which the unbalanced input is connected, and a half-wave resonator for balanced output to which the first and second balanced outputs are connected, the half-wave resonator for balanced output being made up of a half-wave resonator having open-circuited ends, the multi-layer band-pass filter further comprising a capacitor made up of part of the multi-layer substrate and provided in at least one of a location between the unbalanced input and the input resonator and a location between each of the first and second balanced outputs and the half-wave resonator for balanced output, wherein the band-pass filter section incorporates at least one half-wave resonator having open-circuited ends, the open-circuited ends being connected to each other through a capacitor.

Claim 20

A multi-layer band-pass filter comprising: an unbalanced input for receiving unbalanced signals; a first balanced output and a second balanced output for outputting balanced signals; a band-pass filter section provided between the unbalanced input and the first and second balanced outputs and incorporating a plurality of resonators each of which is made up of a TEM line; and a multi-layer substrate used for integrating the resonators, wherein the band-pass filter section incorporates, as the resonators, an input resonator to which the unbalanced input is connected, and a half-wave resonator for balanced output to which the first and second balanced outputs are connected, the half-wave resonator for balanced output being made up of a half-wave resonator having open-circuited ends, the multi-layer band-pass filter further comprising a capacitor made up of part of the multi-layer substrate and provided in at least one of a location between the unbalanced input and the input resonator and a location between each of the first and second balanced outputs and the half-wave resonator for balanced output, wherein the band-pass filter section incorporates at least one half-wave resonator having open-circuited ends, the open-circuited ends being connected to each other through a capacitor.