Band pass filter

Abstract

A band pass filter according to an embodiment of the present invention comprises a plurality of resonators that are each connected at both ends to an input terminal and an output terminal, are electrically connected to each other, and each comprises an inductor and a capacitor. The plurality of resonators comprise: a plurality of first resonators; a plurality of second resonators disposed between the plurality of first resonators; a third resonator disposed between the first resonator and the second resonator and forming parallel resonance; and a fourth resonator disposed between the plurality of second resonators adjacent to each other and forming parallel resonance. It is preferable that the inductor of the third resonator is formed by mutual inductance with the inductor of the first resonator and the inductor of the second resonator, and the inductor of the fourth resonator is formed by mutual inductance with the inductor of each of the second resonators adjacent to each other.

Description

bandpass filter

[0001] The present invention relates to a band-pass filter using an inductor and a capacitor, and more particularly, to a band-pass filter capable of arranging a two-dimensional equivalent circuit in a small, limited three-dimensional space while further improving wideband characteristics.

[0002] A bandpass filter can be configured by arranging multiple resonators that resonate at specific frequencies to pass specific frequencies from the input terminal to the output terminal and attenuate other frequencies so as not to pass the signal.

[0003] For bandpass filters like this, performance metrics that measure the ability to block frequencies outside the passband are crucial for eliminating various noises generated within mobile communication devices. For example, representative performance metrics for bandpass filters include insertion loss, return loss, and attenuation.

[0004] Typically, insertion loss is the loss that occurs within the passband, reflection loss is the power loss that returns to the input terminal, and attenuation refers to the amount of output power relative to the input of a signal that passes through at a frequency other than the passband.

[0005] Therefore, insertion loss and reflection loss are better when the power loss is small and the power that passes through is large, and attenuation is better when the loss is large and the power that passes through is small.

[0006] While various technologies are being developed to eliminate noise and achieve faster wireless communication, the most fundamental solution is to broaden the wireless communication bandwidth. Accordingly, bandpass filters must exhibit superior attenuation and low insertion loss characteristics, and technologies capable of improving wideband performance may also be required.

[0007] The problem to be solved by the present invention is to provide a high-performance bandpass filter that can improve wideband characteristics even in a limited three-dimensional space and implement excellent attenuation characteristics and low insertion loss characteristics.

[0008] According to one embodiment of the present invention, a bandpass filter includes a plurality of resonators, each of which is electrically connected to an input terminal and an output terminal at both ends and each of which is composed of an inductor and a capacitor, wherein the plurality of resonators includes a plurality of first resonators, a plurality of second resonators arranged between the plurality of first resonators, a third resonator arranged between the first resonators and the second resonators and forming a parallel resonance, and a fourth resonator arranged between the plurality of adjacent second resonators and forming a parallel resonance, and it is preferable that the inductor of the third resonator is formed by mutual inductance with the inductor of the first resonator and the inductor of the second resonator, and the inductor of the fourth resonator is formed by mutual inductance with the inductor of each of the adjacent second resonators.

[0009] Furthermore, it is preferable that the capacitor of the third resonator and the capacitor of the fourth resonator are electrically coupled by a conductor pattern that forms capacitance between the plurality of resonators.

[0010] Furthermore, it is preferable that the capacitor and inductor of the third resonator form a zero point through resonant coupling.

[0011] Furthermore, it is preferable that the capacitor and inductor of the third resonator are arranged so that the zero point has a positive pole located at a frequency lower than the passband of the bandpass filter.

[0012] Furthermore, it is preferable that the capacitor and inductor of the fourth resonator form poles through resonant coupling.

[0013] Furthermore, it is preferable that the capacitor and inductor of the fourth resonator are arranged so that the poles have a negative coupling higher than the passband of the bandpass filter.

[0014] Furthermore, it is preferable that the physical distance between the inductor of the first resonator and the inductor of the second resonator is at least twice the physical distance between the inductors of the adjacent second resonators.

[0015] Furthermore, it is preferable that two poles are formed in the capacitor and inductor of the third resonator, one of the two poles has a lower frequency than the other, and the other pole is arranged adjacent to the passband of the bandpass filter.

[0016] Furthermore, it is preferable that the capacitor of the first resonator includes a plurality of electrodes, some of the plurality of electrodes are grounded to ground potential and the rest are not grounded to ground potential, and the band-pass filter further includes a conductor pattern that forms a capacitance with the electrodes of the capacitor of the first resonator that are not grounded to ground potential.

[0017] Furthermore, it is preferable that the poles formed by the cross capacitance are formed in a frequency band less than three times the center frequency at a frequency higher than the passband of the band-pass filter, and that two or more poles are arranged at a frequency lower than the passband.

[0018] Furthermore, it is preferable that the bandpass filter further includes a plurality of fifth resonators each including an inductor and a capacitor, each of which is arranged adjacent to the input terminal and the output terminal, and the inductor of the fifth resonator is arranged for impedance matching, and the capacitor of the fifth resonator is formed in parallel with the inductor of the fifth resonator.

[0019] Furthermore, it is preferable that the capacitor and inductor of the fifth resonator form poles by parallel resonance.

[0020] Furthermore, it is preferable that the pole formed by the fifth resonator be placed in a band between the center frequency of the passband of the band-pass filter and a frequency three times the center frequency.

[0021] Furthermore, it is preferable that the bandpass filter further includes a coupling control conductor pattern arranged to overlap on the upper portion of the inductors of each of the plurality of second resonators, and that the coupling control conductor pattern is configured to control the amount of electromagnetic coupling formed between the inductors of each of the plurality of second resonators.

[0022] Furthermore, it is preferable that the coupling control conductor pattern includes a plurality of first portions overlapping the inductors of each of the plurality of second resonators and a plurality of second portions disposed between the inductors of each of the plurality of second resonators.

[0023] The present invention has the effect of enabling implementation of a band-pass filter with improved wideband characteristics even in a narrower space.

[0024] Additionally, it has the effect of enabling the implementation of a high-performance bandpass filter with excellent attenuation characteristics and low insertion loss characteristics.

[0025] Figure 1 is an equivalent circuit of a bandpass filter according to one embodiment of the present invention.

[0026] Figure 2 is a perspective view of a combined bandpass filter according to one embodiment of the present invention.

[0027] Figure 3 is an exploded perspective view of a bandpass filter according to one embodiment of the present invention.

[0028] Figure 4a is an exemplary drawing for explaining mutual inductance formed between two lines with the same current direction.

[0029] Figure 4b is an example drawing for explaining mutual inductance formed between two lines with different current directions.

[0030] Figure 5a is an example graph for explaining a case in which a graph showing attenuation characteristics according to frequency has a positive pole.

[0031] Fig. 5b is an equivalent circuit that has a positive pole in the same graph as Fig. 5a.

[0032] Figure 6a is an example graph for explaining a case where a negative pole is present in a graph showing attenuation characteristics according to frequency.

[0033] Figure 6b is an equivalent circuit that has a negative pole in the same graph as Figure 6a.

[0034] Fig. 7 is a graph showing the attenuation characteristics of a bandpass filter according to one embodiment of the present invention.

[0035] Fig. 8 is a fifth inductor in a bandpass filter according to an embodiment of the present invention. This is a graph to explain pole 5 added by the resonance of the fifth capacitor.

[0036] FIG. 9 is a drawing for explaining a coupling control conductor pattern of a bandpass filter according to one embodiment of the present invention.

[0037] The bandpass filter of the present invention will now be described in detail with reference to the accompanying drawings. The drawings presented below are provided as examples to ensure that those skilled in the art can fully grasp the spirit of the present invention. Therefore, the present invention is not limited to the drawings presented below and may be embodied in other forms. Furthermore, like reference numerals designate like elements throughout the specification.

[0038] At this time, if there is no other definition in the technical and scientific terms used, they have the meaning commonly understood by a person of ordinary skill in the technical field to which this invention belongs, and the description of known functions and configurations that may unnecessarily obscure the gist of the present invention in the following description and attached drawings are omitted.

[0039] Figure 1 is an equivalent circuit of a bandpass filter according to one embodiment of the present invention.

[0040] Figure 2 is a perspective view of a combined bandpass filter according to one embodiment of the present invention.

[0041] Figure 3 is an exploded perspective view of a bandpass filter according to one embodiment of the present invention.

[0042] A bandpass filter according to one embodiment of the present invention includes a plurality of resonators, each of which is electrically connected to an input terminal (IN) and an output terminal (OUT) at both ends and each of which is composed of an inductor and a capacitor.

[0043] The plurality of resonators are composed of a plurality of first resonators (L R1, C R1 ), multiple first resonators (L R1, C R1 ) are arranged between a plurality of second resonators (L R2, C R2 ), first resonator (L R1, C R1 ) and the second resonator (L R2, C R2 ) and a third resonator (L) that forms a parallel resonance m1, C pos1 ), and a plurality of second resonators (L) adjacent to each other R2, C R2 ) and the fourth resonator (L) is placed between them and forms a parallel resonance. m2, C neg1 ) are included. Each of the plurality of resonators can be arranged to achieve series resonance or parallel resonance.

[0044] In the present invention, the third resonator (Lm1, C pos1 ) of the third inductor (L m1 ) is the first resonator (L R1, C R1 ) of the first inductor (L R1 ) and the second resonator (L R2, C R2 ) of the second inductor (L R2 ) and mutual inductance, and the fourth resonator (L m2, C neg1 ) of the fourth inductor (L m2 ) are adjacent second resonators (L R2, C R2 ) each second inductor (L R2 ) and mutual inductance.

[0045] And, the third resonator (L m1, C pos1 ) of the third capacitor (C pos1 ) and the fourth resonator (L m2, C neg1 ) of the fourth capacitor (C neg1 ) is preferably configured to form electrical coupling by a conductive pattern that forms capacitance between multiple resonators.

[0046] First resonator (L R1, C R1 ) of the capacitor (C R1 ) includes a plurality of electrodes, some of which are grounded to the ground (GND) potential and the rest are not grounded to the ground (GND) potential, and the band-pass filter is a first resonator (L R1, C R1 ) of the capacitor (C R1 ) and the cross capacitance (C) of the electrode not grounded to the ground (GND) potential cross ) further includes a conductor pattern (C-LINE) forming a plurality of cross capacitances (C cross ) can be connected between, and may be referred to as, but is not limited to, a conductor line.

[0047] In this way, a bandpass filter including multiple resonators can be designed to suit the filter's requirements by setting the frequencies at which poles and zeros occur.

[0048] For example, if the zero formed by resonant coupling is located at a frequency lower than the pass band, it may be referred to as positive coupling, and if the pole formed by resonant coupling is located at a frequency higher than the pass band, it may be referred to as negative coupling.

[0049] Accordingly, in the band pass filter of the present invention, the third resonator (L m1, C pos1 ) of the capacitor (C pos1 ) and inductor (L m1 ) is desirable to form a zero point through resonant coupling. That is, the third resonator (L m1, C pos1 ) of the capacitor (C pos1 ) and inductor (L m1 ) is preferably arranged so that the positive pole is located at a frequency lower than the passband of the bandpass filter.

[0050] 4th resonator (L m2, C neg1 ) of the capacitor (C neg1 ) and the inductor are resonantly coupled (L m2 ) is desirable to form a pole. That is, the fourth resonator (L m2, C neg1 ) of the capacitor (C neg1 ) and inductor (L m2 ) is preferably arranged so that the poles have a negative coupling higher than the passband of the bandpass filter.

[0051] Figure 4a is an exemplary drawing for explaining mutual inductance formed between two lines with the same current direction.

[0052] Figure 4b is an example drawing for explaining mutual inductance formed between two lines with different current directions.

[0053] For example, as shown in FIGS. 4a and 4b, the mutual inductance L formed between the two lines 1 and 2, which are arranged parallel to each other Mut1 and L Mut2 The size of the current varies depending on the direction of the current flowing between the two lines.

[0054] In Fig. 4a, lines 1 and 2 have ground contacts and open portions in the same direction. In this case, the magnetic fields of the mutual inductance formed in the two lines are formed in the same direction and cancel each other out, so their magnitude can be greatly reduced.

[0055] On the other hand, in Fig. 4b, the mutual inductance formed in lines 1 and 2 can have a much larger value than in Fig. 4a because the magnetic fields are formed in different directions.

[0056] Meanwhile, the value of mutual inductance formed in lines 1 and 2 in Fig. 4a may also vary depending on the distance d between lines 1 and 2. That is, as the distance d between lines 1 and 2 decreases, the value of mutual inductance may increase.

[0057] At this time, the slope of the attenuation characteristic of the bandpass filter can be determined according to the mutual inductance value between lines 1 and 2.

[0058] For example, the slope of the attenuation characteristic of a band-pass filter may be steeper in the vicinity of the pass band as the mutual inductance value between lines 1 and 2 becomes smaller, and the attenuation characteristic may deteriorate after passing the pole.

[0059] Hereinafter, the attenuation characteristics of the band-pass filter will be described with reference to FIGS. 5a to 6b.

[0060] Figure 5a is an example graph for explaining a case in which a graph showing attenuation characteristics according to frequency has a positive pole.

[0061] Fig. 5b is an equivalent circuit that has a positive pole in the same graph as Fig. 5a.

[0062] Figure 6a is an example graph for explaining a case where a negative pole is present in a graph showing attenuation characteristics according to frequency.

[0063] Figure 6b is an equivalent circuit that has a negative pole in the same graph as Figure 6a.

[0064] Referring to FIGS. 5a to 6b, assuming that the same pass bandwidth is implemented, the smaller the mutual inductance due to magnetic coupling between inductors, the more rapidly the attenuation is at the frequency side where the pole is located around the pass bandwidth, whereas the attenuation characteristic deteriorates as it passes the pole, and the attenuation characteristic may deteriorate on the other side of the frequency where the pole is not located.

[0065] Accordingly, by utilizing the attenuation characteristics of such a bandpass filter, a bandpass filter having three or more resonators can be implemented as a desired bandpass filter by appropriately arranging them to have both positive and negative poles.

[0066] In a bandpass filter according to one embodiment of the present invention, a third resonator (L m1, C pos1 ) of the third capacitor (C pos1 ) and a third inductor (L m1 ) is arranged to have a positive pole, and the fourth resonator (L m2, C neg1 ) of the fourth capacitor (C neg1 ) and the fourth inductor (L m2 ) is arranged to have a negative pole.

[0067] At this time, the band-pass filter has two third resonators (L m1, C pos1 ) can be placed, so that two positive poles can exist. Therefore, frequencies lower than the passband are generated by the third inductor (L m1 ) and the fourth inductor (L m2) have the same value, the attenuation slope may be doubled, which may deteriorate the flatness characteristic of the passband. In addition, it may be difficult to implement the attenuation characteristic at a frequency higher than the passband where only one pole exists.

[0068] In a bandpass filter according to one embodiment of the present invention, a first resonator (L R1, C R1 ) of the inductor (L R1 ) and the second resonator (L R2, C R2 ) of the inductor (L R2 ) is the physical distance between the adjacent second resonators (L R2, C R2 ) of the inductor (L R2 ) is preferably at least twice the physical distance between them.

[0069] Accordingly, it can be configured to implement similar attenuation slopes on the left and right sides centered on the passband.

[0070] Additionally, two third resonators (L m1, C pos1 ) of the third capacitor (C pos1 ) and a third inductor (L m1 ) has two poles, so it is difficult to obtain high attenuation characteristics in a wide band of low frequencies in a passband where the pole exists only at one frequency.

[0071] At this time, the fourth resonator (L m2, C neg1 ) of the fourth inductor (L m2 ) to have a smaller value, which may limit the physical implementation of the electrode to obtain a steep slope at frequencies higher than the passband. In addition, there is a problem that it is impossible to obtain high attenuation characteristics in a wide frequency band higher than the passband because there is only one pole.

[0072] Accordingly, in a band-pass filter according to one embodiment of the present invention, a third resonator (L m1, C pos1 ) of the capacitor (Cpos1 ) and inductor (L m1 ) two poles are formed, one of the two poles has a lower frequency than the other, and it is preferable that the other pole is positioned adjacent to the passband of the bandpass filter.

[0073] Therefore, the third resonator (L m1, C pos1 ) of the capacitor (C pos1 ) and inductor (L m1 ) by configuring one of the two poles to be at a lower frequency and the other to be closer to the passband, which has the effect of obtaining a more rapid attenuation characteristic and an excellent attenuation characteristic over a wider frequency range.

[0074] Fig. 7 is a graph showing the attenuation characteristics of a bandpass filter according to one embodiment of the present invention.

[0075] In a bandpass filter according to one embodiment of the present invention, a first resonator (L R1, C R1 ) of the capacitor (C R1 ) and the cross capacitance (C) of the electrode not grounded to the ground (GND) potential cross ) is arranged, one more pole can be additionally arranged in a frequency band higher than the pass band, as in pole 4 of Fig. 7. Accordingly, since two poles can be arranged in a frequency band higher than the pass band, there is an effect of being able to implement excellent attenuation characteristics.

[0076] At this time, the cross capacitance (C cross) are arranged more widely, one of the two poles formed in the high frequency region will be closer to the passband and move with a steeper slope, while the other will be further away from the passband. This configuration allows for excellent attenuation characteristics not only in the frequency range lower than the passband but also in the high frequency range, thereby improving the attenuation characteristics over a wider frequency band.

[0077] Meanwhile, the cross capacitance (C cross ) is formed in a frequency band less than three times the center frequency (fo) at a frequency higher than the passband of the band-pass filter, and it is preferable that two or more poles are arranged at a frequency lower than the passband. That is, in the band-pass filter of the present invention, two or more poles are separated and arranged at a frequency lower than the passband, and at a frequency higher than the passband, the cross capacitance (C cross ) can be formed at a frequency less than three times the center frequency (fo) of the bandpass filter.

[0078] FIG. 8 is a graph for explaining pole 5 added by resonance of the fifth inductor (Lp1) and the fifth capacitor (Cp1) in a bandpass filter according to one embodiment of the present invention.

[0079] A bandpass filter according to one embodiment of the present invention is arranged adjacent to the input terminal (IN) and the output terminal (OUT), respectively, and includes a fifth inductor (L p1 ) and the fifth capacitor (C p1 ) each comprising a plurality of fifth resonators (L p1, C p1 ) is included.

[0080] Fifth resonator (L p1, C p1 ) of the fifth inductor (L p1 ) is placed for impedance matching, and the fifth resonator (L p1, Cp1 ) of the fifth capacitor (C p1 ) is the fifth resonator (L p1, C p1 ) of the fifth inductor (L p1 ) is preferably formed in parallel.

[0081] Fifth resonator (L p1, C p1 ) of the fifth capacitor (C p1 ) and the fifth inductor (L p1 ) can form a pole by parallel resonance. Accordingly, the fifth capacitor (C p1 ) and the fifth inductor (L p1 ) value, the added pole can be positioned in the part of the passband where improvement in the attenuation characteristic of the high frequency band (fo ~ 3 x fo) is required, thereby achieving improvement in the attenuation characteristic.

[0082] Referring to Fig. 8, the fifth resonator (L p1, C p1 ) can be placed in a band between the center frequency of the passband of the band-pass filter and a frequency three times the center frequency.

[0083] Accordingly, since more poles can be added at frequencies higher than the passband, the effect of obtaining not only a sharp attenuation characteristic at a frequency adjacent to the passband without reducing the insertion loss, but also an excellent attenuation characteristic can be obtained even after passing the poles adjacent to the passband.

[0084] FIG. 9 is a drawing for explaining a coupling control conductor pattern (TP) of a bandpass filter according to one embodiment of the present invention.

[0085] A bandpass filter according to one embodiment of the present invention comprises a plurality of second resonators (L R2, C R2 ) each inductor (L R2 ) further includes a coupling control conductor pattern (TP) arranged to overlap on the upper side of the first inductor (L). The coupling control conductor pattern (TP) is formed by a first inductor (LR1 ) and a second inductor (L R2 ) is a conductive pattern placed at the top in the upward direction.

[0086] The coupling control conductor pattern (TP) comprises a plurality of second resonators (L R2, C R2 ) each second inductor (L R2 ) can be configured to control the amount of electromagnetic coupling formed between them.

[0087] Referring to FIG. 9, the coupling control conductor pattern (TP) comprises a plurality of second resonators (L R2, C R2 ) each second inductor (L R2 ) and a plurality of first parts and a plurality of second resonators (L) overlapping each other. R2, C R2 ) each second inductor (L R2 ) includes a plurality of second parts arranged between them.

[0088] Two secondary inductors (L R2 ) the mutual inductance between the two inductors decreases as the distance (w1) between them decreases. At this time, the two second inductors (L R2 ) can be implemented by using a coupling having a negative pole by the mutual inductance value between them. Accordingly, two second inductors (L) coupled to have a negative pole R2 ) by arranging the coupling control conductor pattern (TP) on the second inductor (L R2 ) can control the electromagnetic coupling between the second inductor (L R2 ) can be made smaller to implement a bandpass filter with wider negative poles.

[0089] For example, when the vertical distances from one of the plurality of second portions to the end of the closest first portion in the coupling control conductor pattern (TP) are g1 and g2, the closer g1 or g2 is to 0, the more the two second inductors (L R2) The negative pole formed between them has the effect of widening the passband as it is formed at a higher frequency.

[0090] And, when the distance between the plurality of second parts in the coupling control conductor pattern (TP) is g3, even when g3 approaches 0, the two second inductors (L R2 ) The negative pole formed between them is formed at a higher frequency, which has the effect of widening the passband.

[0091] Also, the sum of the distances of g1 and g2 is the distance between the two second inductors (L R2 ) are arranged with a value similar to the distance W1 between them, the same effect occurs as when the coupling control conductor pattern (TP) is not arranged. Conversely, when the sum of the distances g1 and g2 is equal to the sum of the distances of the two second inductors (L R2 ) becomes larger than the distance W1 between the two second inductors (L R2 ) has the advantage that the poles formed by the band pass filter are formed closer and closer to the pass band, thereby implementing a sharp attenuation. Therefore, in the band pass filter according to one embodiment of the present invention, two second inductors (L R2 ) by arranging the coupling control conductor pattern (TP) on the substrate, a high-performance bandpass filter can be implemented even in a narrower space.

[0092] As described above, although the present invention has been described through limited embodiments and drawings, these are provided only to help with the overall understanding of the present invention, and the present invention is not limited to the above embodiments, and various modifications and variations are possible from the technical idea of ​​the present invention by a person having ordinary knowledge in the technical field to which the present invention belongs.

[0093] Therefore, the idea of ​​the present invention is not limited to the described embodiments, and all things that have equivalent or equivalent modifications to the claims described below are considered to fall within the scope of the idea of ​​the present invention.

[0094]

[0095] [Explanation of symbols]

[0096] IN: Input terminal OUT: Output terminal

[0097] L R1: First inductor L R2: Second inductor

[0098] L m1: Third inductor L m2: 4th inductor

[0099] L p1: 5th inductor C-LINE: Conductor line

[0100] C R1: First capacitor C R2: Second capacitor

[0101] C pos1: Third capacitor C neg1: 4th capacitor

[0102] C p1: Fifth capacitor C cross: Cross capacitor

[0103] TP: Coupling control conductor pattern GND: Ground

Claims

1. It includes a plurality of resonators, each of which is electrically connected to an input terminal and an output terminal and each of which is composed of an inductor and a capacitor. The above plurality of resonators are, Multiple first resonators; A plurality of second resonators arranged between the plurality of first resonators; A third resonator arranged between the first resonator and the second resonator and forming a parallel resonance; and A bandpass filter characterized by including a fourth resonator arranged between a plurality of adjacent second resonators and forming a parallel resonance.

2. In paragraph 1, The inductor of the third resonator is formed by mutual inductance with the inductor of the first resonator and the inductor of the second resonator, A band-pass filter in which the inductor of the fourth resonator is formed by mutual inductance with the inductors of each of the adjacent second resonators.

3. In paragraph 1, A band-pass filter in which the capacitor of the third resonator and the capacitor of the fourth resonator are electrically coupled by a conductor pattern that forms capacitance between the plurality of resonators.

4. In paragraph 1, A band-pass filter in which the capacitor and inductor of the third resonator form a zero point through resonant coupling.

5. In paragraph 4, A band-pass filter, wherein the capacitor and inductor of the third resonator are arranged so that the zero point has a positive pole located at a frequency lower than the passband of the band-pass filter.

6. In paragraph 1, A band-pass filter in which the capacitor and inductor of the fourth resonator form poles through resonant coupling.

7. In paragraph 6, A band-pass filter in which the capacitor and inductor of the fourth resonator are arranged so that the poles have negative coupling in a frequency band higher than the passband of the band-pass filter.

8. In paragraph 1, A band-pass filter, wherein the physical distance between the inductor of the first resonator and the inductor of the second resonator is at least twice the physical distance between the inductors of the adjacent second resonators.

9. In paragraph 1, In the capacitor and inductor of the third resonator, two poles are formed, A band-pass filter, wherein one of the two poles has a lower frequency than the other, and the other pole is positioned adjacent to the passband of the band-pass filter.

10. In paragraph 1, The capacitor of the above first resonator includes a plurality of electrodes, Some of the above plurality of electrodes are grounded to ground potential and the rest are not grounded to ground potential, A band-pass filter, wherein the band-pass filter further includes a conductor pattern that forms a cross capacitance with an electrode that is not grounded to ground potential in the capacitor of the first resonator.

11. In paragraph 10, The pole formed by the above cross capacitance is formed in a frequency band less than three times the center frequency in a frequency band higher than the passband of the band-pass filter, A band-pass filter in which two or more poles are placed at frequencies below the above passband.

12. In paragraph 1, Further comprising a plurality of fifth resonators each of which is arranged adjacent to the input terminal and the output terminal and each of which includes an inductor and a capacitor; The inductor of the fifth resonator is placed for impedance matching, A band-pass filter in which the capacitor of the fifth resonator is formed in parallel with the inductor of the fifth resonator.

13. In paragraph 12, A band-pass filter in which the capacitor and inductor of the fifth resonator form poles due to parallel resonance.

14. In paragraph 13, A band-pass filter, wherein the pole formed by the fifth resonator is positioned in a band between the center frequency of the passband of the band-pass filter and a frequency three times the center frequency.

15. In paragraph 1, Further comprising a coupling control conductor pattern arranged to overlap on the upper portion of each of the inductors of the plurality of second resonators, A band pass filter, wherein the above coupling control conductor pattern is configured to control the amount of electromagnetic coupling formed between the inductors of each of the plurality of second resonators.

16. In paragraph 15, A bandpass filter, wherein the above-described coupling control conductor pattern comprises a plurality of first portions overlapping the inductors of each of the plurality of second resonators and a plurality of second portions disposed between the inductors of each of the plurality of second resonators.

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