Patent Grant
10957959
The present invention relates to a band-pass filter including a plurality of resonators.
The standardization of fifth-generation mobile communication systems (hereinafter referred to as 5G) is currently ongoing. For 5G, the use of frequency bands of 10 GHz or higher, particularly a quasi-millimeter wave band of 10 to 30 GHz and a millimeter wave band of 30 to 300 GHz, is being studied to expand the frequency band.
One of electronic components used in a communication apparatus is a band-pass filter including a plurality of resonators. Each of the plurality of resonators includes, for example, a conductor portion that is long in one direction.
JP2006-311100A describes a chip-type multistage filter device usable in quasi-millimeter and millimeter wave bands. The chip-type multistage filter device includes a multilayer substrate, first and second surface ground electrodes, first and second internal ground electrodes, and first and second λ/2 resonator electrodes. The multilayer substrate is formed by stacking a plurality of dielectric layers. The multilayer substrate has first and second main surfaces opposed to each other, and first to fourth side surfaces connecting the first and second main surfaces. The first side surface and the second side surface are opposed to each other. The first surface ground electrode is disposed on the first side surface. The second surface ground electrode is disposed on the second side surface. The first internal ground electrode is disposed on one of the dielectric layers of the multilayer substrate that is relatively close to the first main surface. The second internal ground electrode is disposed on another one of the dielectric layers of the multilayer substrate that is relatively close to the second main surface. The first and second λ/2 resonator electrodes are disposed in an area surrounded by the first and second surface ground electrodes and the first and second internal ground electrodes.
JP2003-069306A describes a band-pass filter comprising a plurality of resonators, each of the resonators having a configuration in which a low-impedance line, a high-impedance line, and a low-impedance line are connected in this order. The resonator having such a configuration is a kind of stepped impedance resonator (hereinafter referred to as SIR).
Band-pass filters for use particularly with communication apparatuses of miniature size must undergo miniaturization. However, a band-pass filter that includes a plurality of half-wave resonators, such as the one described in JP2006-311100A, is difficult to miniaturize since the half-wave resonators are large in length.
Reduction in length of the half-wave resonators can be achieved by using SIRs, as described in JP2003-069306A, as the half-wave resonators. However, compared to a resonator formed of a conductor line of constant width, SIRs are lower in unloaded Q. A lower unloaded Q of resonators leads to a higher insertion loss of the band-pass filter. Thus, if all the resonators are configured as SIRs as described in JP2003-069306A, an excessively high insertion loss of the band-pass filter would result.
It is an object of the present invention to provide a band-pass filter that includes a plurality of resonators and achieves miniaturization while preventing an increase in insertion loss.
A band-pass filter of the present invention includes: a main body formed of a dielectric; a first input/output port and a second input/output port integrated with the main body; and N resonators. N is an integer greater than or equal to 3. The N resonators are provided within the main body, located between the first input/output port and the second input/output port in circuit configuration, and configured so that electromagnetic coupling is established between every two of the resonators adjacent to each other in circuit configuration.
The N resonators include at least a pair of first and second resonators, the first and second resonators being non-adjacent to each other in circuit configuration, and a third resonator located between the first and second resonators in circuit configuration. When one of the N resonators that is i-th closest to the first input/output port in circuit configuration is referred to as an i-th stage resonator, the first resonator is an i-th stage resonator where i has a value smaller than (N+1)/2, and the second resonator is an i-th stage resonator where i has a value greater than (N+1)/2.
The first resonator includes a first resonator conductor portion formed of a conductor line. The second resonator includes a second resonator conductor portion formed of a conductor line. The third resonator includes a third resonator conductor portion formed of a conductor line. Each of the first to third resonator conductor portions has a first end and a second end which are opposite ends of the conductor line. Each of the first and second resonator conductor portions includes a narrow portion, a first wide portion located between the narrow portion and the first end, and a second wide portion located between the narrow portion and the second end. The narrow portion is smaller in width than the first and second wide portions, the width being a dimension in a direction orthogonal to a shortest path connecting the first end and the second end. Each of the first and second resonators is lower in unloaded Q than the third resonator.
In the band-pass filter of the present invention, each of the first to third resonators may be a resonator with open ends.
In the band-pass filter of the present invention, the third resonator conductor portion may include no portion having a width smaller than a width at each of the first end and the second end.
In the band-pass filter of the present invention, each of the first and second resonator conductor portions may be smaller in length of the shortest path than the third resonator conductor portion.
In the band-pass filter of the present invention, the first resonator may be a first stage resonator, and the second resonator may be an N-th stage resonator.
In the band-pass filter of the present invention, N may be an integer greater than or equal to 5. In such a case, the N resonators may include a first pair of first and second resonators, and a second pair of first and second resonators. The first resonator of the first pair of first and second resonators may be a first stage resonator, and the second resonator of the first pair of first and second resonators may be an N-th stage resonator. The first resonator of the second pair of first and second resonators may be a second stage resonator, and the second resonator of the second pair of first and second resonators may be an N−1-th stage resonator.
According to the band-pass filter of the present invention, each of the first and second resonator conductor portions includes a narrow portion, and each of the first and second resonators is lower in unloaded Q than the third resonator. Further, the first resonator is an i-th stage resonator where i has a value smaller than (N+1)/2, and the second resonator is an i-th stage resonator where i has a value greater than (N+1)/2. By virtue of these features, it becomes possible for the band-pass filter of the present invention to achieve miniaturization while preventing an increase in insertion loss.
Other and further objects, features and advantages of the invention will appear more fully from the following description.
Preferred embodiments of the present invention will now be described in detail with reference to the drawings. First, reference is made to
As shown in
The main body 2 includes a multilayer stack 20 composed of a plurality of dielectric layers stacked together. Here, X, Y and Z directions are defined as shown in
The main body 2 has a rectangular parallelepiped shape. The main body 2 has a first end face 2A and a second end face 2B located at opposite ends in the Z direction of the main body 2, and further has four side surfaces 2C, 2D, 2E and 2F connecting the first end face 2A and the second end face 2B. The first end face 2A is also the bottom surface of the main body 2. The second end face 2B is also the top surface of the main body 2. The side surfaces 2C and 2D are located at opposite ends in the Y direction of the main body 2. The side surfaces 2E and 2F are located at opposite ends in the X direction of the main body 2.
The N resonators are located between the first input/output port 3 and the second input/output port 4 in circuit configuration. The N resonators are configured so that electromagnetic coupling is established between every two of the resonators adjacent to each other in circuit configuration. As used herein, the phrase “in circuit configuration” is to describe layout in a circuit diagram, not in a physical configuration.
In the present embodiment, as shown in
The band-pass filter 1 includes a capacitor C12 for establishing capacitive coupling between the resonators 51 and 52, a capacitor C23 for establishing capacitive coupling between the resonators 52 and 53, a capacitor C34 for establishing capacitive coupling between the resonators 53 and 54, a capacitor C45 for establishing capacitive coupling between the resonators 54 and 55, and a capacitor C56 for establishing capacitive coupling between the resonators 55 and 56.
In a band-pass filter including three or more resonators configured so that every two of the resonators adjacent to each other in circuit configuration are coupled to each other, electromagnetic coupling may be established between two resonators that are not adjacent to each other in circuit configuration. Such electromagnetic coupling between non-adjacent resonators will be referred to as cross coupling. As will be described in detail below, the band-pass filter 1 according to the present embodiment has two cross couplings.
In the present embodiment, among the six resonators 51 to 56, the resonator 52, which is the second closest to the first input/output port 3 in circuit configuration, and the resonator 55, which is the second closest to the second input/output port 4 in circuit configuration, are magnetically coupled to each other although they are not adjacent to each other in circuit configuration.
Further, in the present embodiment, among the six resonators 51 to 56, the resonator 51, which is the closest to the first input/output port 3 in circuit configuration, and the resonator 56, which is the closest to the second input/output port 4 in circuit configuration, are capacitively coupled to each other although they are not adjacent to each other in circuit configuration. In
The band-pass filter 1 further includes a capacitor C1 provided between the first input/output port 3 and the resonator 51, and a capacitor C2 provided between the second input/output port 4 and the resonator 56.
The band-pass filter 1 further includes a notch filter section for attenuating a signal of a predetermined frequency (hereinafter referred to as a notch frequency) higher than the passband. The notch filter section includes two lines 91 and 92 each formed of a conductor. Each of the lines 91 and 92 has a first end and a second end opposite to each other. The first end of the line 91 is connected to the first input/output port 3, and the second end of the line 91 is open. The first end of the line 92 is connected to the second input/output port 4, and the second end of the line 92 is open. Each of the lines 91 and 92 has a length of one quarter or nearly one quarter the wavelength corresponding to the notch frequency. Each of the lines 91 and 92 is a quarter-wave resonator that resonates at the notch frequency. The notch frequency is, for example, twice the center frequency of the passband of the band-pass filter 1.
The shield 6 includes a first portion 61 and a second portion 62 spaced from each other in the Z direction, and a connecting portion 63 connecting the first portion 61 and the second portion 62. The first portion 61, the second portion 62 and the connecting portion 63 are arranged to surround the six resonators 51 to 56.
The multilayer stack 20 includes a main portion 21 and a coating portion 22. The main portion 21 is composed of two or more dielectric layers stacked together, among the plurality of dielectric layers constituting the multilayer stack 20. The coating portion 22 is composed of one or more dielectric layers other than the two or more dielectric layers constituting the main portion 21, among the plurality of dielectric layers constituting the multilayer stack 20. The main portion 21 has a first end face 21a and a second end face 21b located at opposite ends in the direction in which the two or more dielectric layers are stacked. The coating portion 22 covers the second end face 21b. The first end face 21a of the main portion 21 coincides with the first end face 2A of the main body 2. The second end face 21b of the main portion 21 is located within the main body 2.
The first portion 61 is formed of a first conductor layer 313 disposed on the first end face 21a. The second portion 62 is formed of a second conductor layer 491 disposed on the second end face 21b. The second portion 62 is interposed between the main portion 21 and the coating portion 22.
The resonators 51, 52, 53, 54, 55, and 56 respectively include resonator conductor portions 510, 520, 530, 540, 550, and 560 each of which is formed of a conductor line. Each of the resonator conductor portions 510, 520, 530, 540, 550 and 560 extends in a direction orthogonal to the Z direction.
Each of the resonator conductor portions 510, 520, 530, 540, 550 and 560 has a first end and a second end which are opposite ends of the conductor line. As mentioned above, each of the resonators 51 to 56 is a resonator with open ends. Thus, both of the first and second ends of each of the resonator conductor portions 510, 520, 530, 540, 550 and 560 are open. Each of the resonator conductor portions 510, 520, 530, 540, 550 and 560 has a length of one half or nearly one half the wavelength corresponding to the center frequency of the passband of the band-pass filter 1.
At least part of the partition 7 extends to pass between the resonator conductor portion 520 and the resonator conductor portion 550 and is in contact with the first portion 61 and the second portion 62. In the present embodiment, specifically, the partition 7 extends in the Z direction. The partition 7 connects the first portion 61 and the second portion 62 via the shortest path.
The partition 7 runs through the two or more dielectric layers constituting the main portion 21. In the present embodiment, the partition 7 includes a plurality of through hole lines 7T each running through the two or more dielectric layers constituting the main portion 21. In
The coupling adjustment section 8 is intended to adjust the magnitude of the capacitive coupling between the resonators 51 and 56. The coupling adjustment section 8 includes a plurality of through hole lines 8T each running through the two or more dielectric layers constituting the main portion 21. In
The connecting portion 63 of the shield 6 includes a plurality of through hole lines 63T each running through the two or more dielectric layers constituting the main portion 21. In
Reference is now made to
Further, a through hole 31T1 connected to the conductor layer 311, and a through hole 31T2 connected to the conductor layer 312 are formed in the dielectric layer 31. Further formed in the dielectric layer 31 are six through holes 7T1 constituting respective portions of the six through hole lines 7T, two through holes 8T1 constituting respective portions of the two through hole lines 8T, and a plurality of through holes 63T1 constituting respective portions of the plurality of through hole lines 63T. All the through holes represented by circles in
Six through holes 7T2 constituting respective portions of the six through hole lines 7T are further formed in each of the dielectric layers 32 and 33. The six through holes 7T1 shown in
Further formed in each of the dielectric layers 32 and 33 are two through holes 8T2 constituting respective portions of the two through hole lines 8T. The two through holes 8T1 shown in
Further formed in each of the dielectric layers 32 and 33 are a plurality of through holes 63T2 constituting respective portions of the plurality of through hole lines 63T. All the through holes represented by circles in
In the dielectric layers 32 and 33, every vertically adjacent through holes denoted by the same reference signs are connected to each other.
In the dielectric layer 34, there are formed a through hole 34T1 connected to the portion of the conductor layer 341 near the first end thereof, and a through hole 34T2 connected to the portion of the conductor layer 342 near the first end thereof.
Further formed in the dielectric layer 34 are six through holes 7T4 constituting respective portions of the six through hole lines 7T. The six through holes 7T2 formed in the third dielectric layer 33 are respectively connected to the six through holes 7T4.
Further formed in the dielectric layer 34 are two through holes 8T4 constituting respective portions of the two through hole lines 8T. The two through holes 8T2 formed in the third dielectric layer 33 are respectively connected to the two through holes 8T4.
Further formed in the dielectric layer 34 are a plurality of through holes 63T4 constituting respective portions of the plurality of through hole lines 63T. All the through holes represented by circles in
Further formed in each of the dielectric layers 35 to 38 are six through holes 7T5 constituting respective portions of the six through hole lines 7T. The six through holes 7T4 shown in
In each of the dielectric layers 35 to 38, there are further formed two through holes 8T5 constituting respective portions of the two through hole lines 8T. The two through holes 8T4 shown in
Further, a plurality of through holes 63T5 constituting respective portions of the plurality of through hole lines 63T are formed in each of the dielectric layers 35 to 38. All the through holes represented by circles in
In the dielectric layers 35 to 38, every vertically adjacent through holes denoted by the same reference signs are connected to each other.
On the patterned surface of the dielectric layer 39, there are further formed conductor layers 393, 394, 395, 396 and 397 for forming the capacitors C12, C23, C34, C45 and C56 shown in
Further, six through holes 7T9 constituting respective portions of the six through hole lines 7T are formed in the dielectric layer 39. The six through holes 7T5 formed in the eighth dielectric layer 38 are respectively connected to the six through holes 7T9.
Further formed in the dielectric layer 39 are two through holes 8T9 constituting respective portions of the two through hole lines 8T. The two through holes 8T5 formed in the eighth dielectric layer 38 are respectively connected to the two through holes 8T9.
Further formed in the dielectric layer 39 are a plurality of through holes 63T9 constituting respective portions of the plurality of through hole lines 63T. All the through holes represented by circles in
The resonator conductor portion 510 has a first end 51a and a second end 51b which are opposite ends of the conductor line. The resonator conductor portion 520 has a first end 52a and a second end 52b which are opposite ends of the conductor line. The resonator conductor portion 530 has a first end 53a and a second end 53b which are opposite ends of the conductor line. The resonator conductor portion 540 has a first end 54a and a second end 54b which are opposite ends of the conductor line. The resonator conductor portion 550 has a first end 55a and a second end 55b which are opposite ends of the conductor line. The resonator conductor portion 560 has a first end 56a and a second end 56b which are opposite ends of the conductor line.
The thick arrows in
The resonator conductor portions 510 and 560 each extend in the X direction. The resonator conductor portions 510 and 560 are arranged in such a positional relationship that a single straight line extending in the X direction intersects the resonator conductor portions 510 and 560. The second end 51b of the resonator conductor portion 510 and the second end 56b of the resonator conductor portion 560 are adjacent to each other and located at a predetermined distance from each other. The distance between the second end 51b and the second end 56b is sufficiently smaller than the length of each of the resonator conductor portions 510 and 560.
As shown in
The narrow portion 51A has a width W51A, the first wide portion 51B has a width W51B, and the second wide portion 51C has a width W51C, each of the widths W51A, W51B and W51C being constant regardless of position in the X direction. The width W51A is smaller than the widths W51B and W51C. The coupling portions 51D and 51E vary in width depending on the position in the X direction. The width of the coupling portion 51D is equal to that of the narrow portion 51A at the boundary between the coupling portion 51D and the narrow portion 51A, and equal to that of the first wide portion 51B at the boundary between the coupling portion 51D and the first wide portion 51B. The width of the coupling portion 51E is equal to that of the narrow portion 51A at the boundary between the coupling portion 51E and the narrow portion 51A, and equal to that of the second wide portion 51C at the boundary between the coupling portion 51E and the second wide portion 51C.
As shown in
The narrow portion 56A has a width W56A, the first wide portion 56B has a width W56B, and the second wide portion 56C has a width W56C, each of the widths W56A, W56B and W56C being constant regardless of position in the X direction. The width W56A is smaller than the widths W56B and W56C. The coupling portions 56D and 56E vary in width depending on the position in the X direction. The width of the coupling portion 56D is equal to that of the narrow portion 56A at the boundary between the coupling portion 56D and the narrow portion 56A, and equal to that of the first wide portion 56B at the boundary between the coupling portion 56D and the first wide portion 56B. The width of the coupling portion 56E is equal to that of the narrow portion 56A at the boundary between the coupling portion 56E and the narrow portion 56A, and equal to that of the second wide portion 56C at the boundary between the coupling portion 56E and the second wide portion 56C.
The resonator conductor portions 520 and 550 each extend in the Y direction. The resonator conductor portions 520 and 550 are adjacent to each other in the X direction and located at a predetermined distance from each other. The distance between the resonator conductor portions 520 and 550 is sufficiently smaller than the length of each of the resonator conductor portions 520 and 550.
The resonator conductor portion 520 has a width W52, the width W52 being constant between the first end 52a and the second end 52b. The resonator conductor portion 550 has a width W55, the width W55 being constant between the first end 55a and the second end 55b.
The first end 52a of the resonator conductor portion 520 is located near the second end 51b of the resonator conductor portion 510. The first end 55a of the resonator conductor portion 550 is located near the second end 56b of the resonator conductor portion 560.
As shown in
As shown in
The first end 53a of the resonator conductor portion 530 and the first end 54a of the resonator conductor portion 540 are adjacent to each other and located at a predetermined distance from each other.
Now, components formed on/in the dielectric layer 40 other than the resonator conductor portions 510, 520, 530, 540, 550 and 560 will be described with reference to
Further, six through holes 7T10 constituting respective portions of the six through hole lines 7T are formed in the dielectric layer 40. The six through holes 7T10 are connected to the conductor layer 7C. The six through holes 7T9 shown in
Further, two through holes 8T10 constituting respective portions of the two through hole lines 8T are formed in the dielectric layer 40. The two through holes 8T9 shown in
Further formed in the dielectric layer 40 are a plurality of through holes 63T10 constituting respective portions of the plurality of through hole lines 63T. All the through holes represented by circles in
In each of the dielectric layers 41 to 48, there are further formed two through holes 8T11 constituting respective portions of the two through hole lines 8T. The two through holes 8T10 shown in
Further, a plurality of through holes 63T11 constituting respective portions of the plurality of through hole lines 63T are formed in each of the dielectric layers 41 to 48. All the through holes represented by circles in
In the dielectric layers 41 to 48, every vertically adjacent through holes denoted by the same reference signs are connected to each other.
The band-pass filter 1 according to the present embodiment is formed by stacking the first to nineteenth dielectric layers 31 to 49 such that the patterned surface of the first dielectric layer 31 also serves as the first end face 2A of the main body 2. A surface of the nineteenth dielectric layer 49 opposite from the patterned surface serves as the second end face 2B of the main body 2. The first to nineteenth dielectric layers 31 to 49 constitute the multilayer stack 20.
The respective resonator conductor portions 510, 520, 530, 540, 550 and 560 of the resonators 51 to 56 are located at the same position in the Z direction within the multilayer stack 20.
The conductor layer 311 forming the first input/output port 3 is connected to the conductor layer 391 shown in
The conductor layer 312 forming the second input/output port 4 is connected to the conductor layer 392 shown in
The conductor layer 393 shown in
The conductor layer 394 shown in
The conductor layer 395 shown in
The conductor layer 396 shown in
The conductor layer 397 shown in
Each of the six through hole lines 7T of the partition 7 is formed by connecting the through holes 7T1, 7T2, 7T4, 7T5, 7T9, 7T10 and 7T11 in series in the Z direction.
In the example shown in
Each of the two through hole lines 8T of the coupling adjustment section 8 is formed by connecting the through holes 8T1, 8T2, 8T4, 8T5, 8T9, 8T10 and 8T11 in series in the Z direction.
Each of the plurality of through hole lines 63T of the connecting portion 63 is formed by connecting the through holes 63T1, 63T2, 63T4, 63T5, 63T9, 63T10 and 63T11 in series in the Z direction.
The band-pass filter 1 according to the present embodiment is designed and configured to have a passband in a quasi-millimeter wave band of 10 to 30 GHz or a millimeter wave band of 30 to 300 GHz, for example. The band-pass filter 1 includes N resonators located between the first input/output port 3 and the second input/output port 4 in circuit configuration. The N resonators are configured so that electromagnetic coupling is established between every two of the resonators adjacent to each other in circuit configuration.
The features of the band-pass filter 1 according to the present embodiment will now be described. Of the N resonators included in the band-pass filter 1, one that is i-th closest to the first input/output port 3 in circuit configuration will hereinafter be referred to as an i-th stage resonator. When N is an even number, an N/2-th stage resonator and an N/2+1-th stage resonator will be referred to as middle resonators. When N is an odd number, an (N+1)/2-th stage resonator will be referred to as a middle resonator. In the present embodiment, specifically, N is 6. Thus, in the embodiment the third stage resonator 53 and the fourth stage resonator 54 are the middle resonators.
In the present embodiment, the N resonators include at least a pair of first and second resonators, the first and second resonators being non-adjacent to each other in circuit configuration, and a third resonator located between the first and second resonators in circuit configuration.
The first resonator is an i-th stage resonator where i has a value smaller than (N+1)/2. This means that the first resonator is closer to the first input/output port 3 than the middle resonators in circuit configuration.
The second resonator is an i-th stage resonator where i has a value greater than (N+1)/2. This means that the second resonator is closer to the second input/output port 4 than the middle resonators in circuit configuration.
The first resonator includes a first resonator conductor portion formed of a conductor line. The second resonator includes a second resonator conductor portion formed of a conductor line. The third resonator includes a third resonator conductor portion formed of a conductor line. Each of the first to third resonator conductor portions has a first end and a second end which are opposite ends of the conductor line.
Each of the first and second resonator conductor portions includes a narrow portion, a first wide portion located between the narrow portion and the first end, and a second wide portion located between the narrow portion and the second end. The narrow portion is smaller in width than the first and second wide portions, the width being a dimension in a direction orthogonal to the shortest path connecting the first end and the second end. Each of the first and second resonators is lower in unloaded Q than the third resonator. Each of the first and second resonator conductor portions may be smaller in length of the shortest path than the third resonator conductor portion.
The above-described resonator with the resonator conductor portion including the narrow portion, the first wide portion and the second wide portion is a kind of SIR. Given the same resonant frequency, forming a resonator as an SIR results in a lower unloaded Q while enabling reduction in length of the shortest path of the resonator conductor portion, as compared to a case where the resonator is not configured as an SIR.
In the present embodiment, the first resonator is the first stage resonator 51, and the second resonator is the N-th stage resonator, i.e., the sixth stage resonator 56. Further, in the present embodiment there are four third resonators. Specifically, the second to fifth stage resonators 52 to 55 are the third resonators. The resonator conductor portion 510 corresponds to the first resonator conductor portion. The resonator conductor portion 560 corresponds to the second resonator conductor portion. The resonator conductor portions 520, 530, 540 and 550 each correspond to the third resonator conductor portion. The resonators 51 and 56 are each lower in unloaded Q than the resonators 52, 53, 54 and 55.
As has been described with reference to
Each of the resonator conductor portions 520, 530, 540 and 550 includes no portion having a width smaller than the width at each of the first end and the second end. In the present embodiment, in particular, each of the resonator conductor portions 520, 530, 540 and 550 has a width constant between the first end and the second end. None of the resonators 52 to 55 are SIRs.
The length of the shortest path of the resonator conductor portion of each resonator depends on the resonant frequency of the resonator. The resonators 51 to 56 are designed so that their resonant frequencies are equal to or close to the center frequency of the passband of the band-pass filter 1. However, the resonant frequencies of the resonators 51 to 56 are not necessarily equal to each other. Thus, the shortest paths 51P and 56P of the resonator conductor portions 510 and 560 of the resonators 51 and 56, which are SIRs, are not necessarily smaller in length than the shortest paths 52P, 53P, 54P and 55P of the resonator conductor portions 520, 530, 540 and 550 of the resonators 52 to 55, none of which are SIRs.
In the present embodiment, in particular, the shortest paths 51P and 56P of the resonator conductor portions 510 and 560 are each smaller in length than the shortest paths 53P and 54P of the resonator conductor portions 530 and 540. The length of each of the shortest paths 52P and 55P of the resonator conductor portion 520 and 550 is equal or almost equal to the length of each of the shortest paths 51P and 56P.
Now, the unloaded Q of an i-th stage resonator will be denoted by the symbol Qui, and the normalized element value of the i-th stage resonator will be denoted by the symbol gi. The insertion loss at the center frequency of the passband of the band-pass filter 1 based on the unloaded Qs of the N resonators is proportional to the sum total of the values of gi/Qui for the N resonators.
If an i-th stage resonator is configured as an SIR, the i-th stage resonator has a lower Qui than in the case where it is formed of a conductor line of constant width. This results in an increase in insertion loss. If all of the N resonators are configured as SIRs, an excessively high insertion loss would result. In view of this, in the present embodiment, only some, not all, of the N resonators are configured as SIRs.
The normalized element value gi of a band-pass filter including N resonators depends on the characteristics of the filter; however, typically, the lesser the value of i than (N+1)/2, or the greater the value of i above (N+1)/2, the smaller is the normalized element value gi. For example, if the N resonators have the same resonant frequency and the band-pass filter has a maximally-flat characteristic, gi is expressed as 2 sin((2i−1)π/2N). In the present embodiment, a resonator that is located closer to the first input/output port 3 or the second input/output port 4 in circuit configuration is smaller in normalized element value gi and lower in the ratio of the amount of change in insertion loss to the amount of change in Qui.
Therefore, in the case of configuring only some of the resonators as SIRs, an increase in insertion loss can be reduced by selecting a resonator located closer to the first input/output port 3 or the second input/output port 4 to be an SIR, rather than a middle resonator or a resonator located near the middle resonator in circuit configuration.
In view of the above, in the present embodiment, only the first stage resonator 51 and the sixth stage resonator 56, which are the closest of all the N resonators to the first input/output port 3 and the second input/output port 4 in circuit configuration, respectively, are configured as SIRs.
According to the present embodiment, since the resonators 51 and 56 configured as SIRs can achieve size reduction, it becomes possible to miniaturize the band-pass filter 1. Further, according to the present embodiment, since only the resonators 51 and 56 are configured as SIRs, it is possible to reduce an increase in insertion loss of the band-pass filter 1.
An example of unloaded Qs of the resonators 51 to 56 of the present embodiment will now be shown. In this example, the first and sixth stage resonators 51 and 56 have an unloaded Q of 250. The second and fifth stage resonators 52 and 55 have an unloaded Q of 288. The third and fourth stage resonators 53 and 54 have an unloaded Q of 253. Thus, in this example, each of the first and sixth stage resonators 51 and 56 is lower in unloaded Q than the second to fifth stage resonators 52 to 55.
Next, a description will be given of the results of a simulation on the band-pass filter 1 according to the present embodiment. The simulation determined the frequency response of insertion loss for each of first to third models of the band-pass filter 1. The first to third models have different combinations of unloaded Qs of the resonators 51 to 56.
In the first model, all the resonators 51 to 56 have an unloaded Q of 200. In the second model, the resonators 51 and 56 have an unloaded Q of 100, and the resonators 52 to 55 have an unloaded Q of 200. In the third model, the resonators 52 and 55 have an unloaded Q of 100, and the resonators 51, 53, 54 and 56 have an unloaded Q of 200.
The center frequency of the passband of each of the first to third models is approximately 28 GHz. As shown in
By configuring a resonator as an SIR, it becomes possible to increase the ratio of a higher-order mode resonant frequency to a fundamental mode resonant frequency. According to the present embodiment, configuring the resonators 51 and 56 as SIRs allows the higher-order mode resonant frequencies of the resonators 51 and 56 to be higher. The present embodiment thereby makes it possible to prevent the attenuation characteristic of the band-pass filter 1 in a frequency region higher than the passband from being degraded due to the higher-order mode.
A second embodiment of the present invention will now be described. First, the configuration of a band-pass filter according to the second embodiment will be described with reference to
The band-pass filter 100 according to the present embodiment includes the main body 2, the first input/output port 3, the second input/output port 4, N resonators, the shield 6, and a partition 107. The main body 2 includes the multilayer stack 20.
The N resonators are located between the first input/output port 3 and the second input/output port 4 in circuit configuration. In the present embodiment, N is 7, and the N resonators are seven resonators 151, 152, 153, 154, 155, 156 and 157. The seven resonators 151, 152, 153, 154, 155, 156 and 157 are arranged in this order, from closest to farthest, from the first input/output port 3 in circuit configuration. The resonators 151 to 157 are configured so that the resonators 151 and 152 are adjacent to each other in circuit configuration and are electromagnetically coupled to each other, the resonators 152 and 153 are adjacent to each other in circuit configuration and are electromagnetically coupled to each other, the resonators 153 and 154 are adjacent to each other in circuit configuration and are electromagnetically coupled to each other, the resonators 154 and 155 are adjacent to each other in circuit configuration and are electromagnetically coupled to each other, the resonators 155 and 156 are adjacent to each other in circuit configuration and are electromagnetically coupled to each other, and the resonators 156 and 157 are adjacent to each other in circuit configuration and are electromagnetically coupled to each other. In the present embodiment, the electromagnetic coupling between every two of the resonators adjacent to each other in circuit configuration is specifically capacitive coupling. In the present embodiment, each of the resonators 151 to 157 is a resonator with open ends, and also a half-wave resonator.
The first portion 61, the second portion 62 and the connecting portion 63 of the shield 6 are arranged to surround the seven resonators 151 to 157. The first portion 61 is formed of a first conductor layer 1313 disposed on the first end face 21a of the main portion 21 of the multilayer stack 20. The second portion 62 is formed of a second conductor layer 1491 disposed on the second end face 21b of the main portion 21 of the multilayer stack 20.
The band-pass filter 100 includes a capacitor C112 for establishing capacitive coupling between the resonators 151 and 152, a capacitor C123 for establishing capacitive coupling between the resonators 152 and 153, a capacitor C134 for establishing capacitive coupling between the resonators 153 and 154, a capacitor C145 for establishing capacitive coupling between the resonators 154 and 155, a capacitor C156 for establishing capacitive coupling between the resonators 155 and 156, and a capacitor C167 for establishing capacitive coupling between the resonators 156 and 157.
In the present embodiment, the resonator 152 and the resonator 156 are magnetically coupled to each other although they are not adjacent to each other in circuit configuration.
Further, in the present embodiment, the resonator 153 and the resonator 155 are capacitively coupled to each other although they are not adjacent to each other in circuit configuration. In
The resonators 151, 152, 153, 154, 155, 156 and 157 respectively include resonator conductor portions 1510, 1520, 1530, 1540, 1550, 1560 and 1570 each of which is formed of a conductor line. Each of the resonator conductor portions 1510, 1520, 1530, 1540, 1550, 1560 and 1570 extends in a direction orthogonal to the Z direction.
Each of the resonator conductor portions 1510, 1520, 1530, 1540, 1550, 1560 and 1570 has a first end and a second end which are opposite ends of the conductor line. As mentioned above, each of the resonators 151 to 157 is a resonator with open ends. Thus, both of the first and second ends of each of the resonator conductor portions 1510, 1520, 1530, 1540, 1550, 1560 and 1570 are open. Each of the resonator conductor portions 1510, 1520, 1530, 1540, 1550, 1560 and 1570 has a length of one half or nearly one half the wavelength corresponding to the center frequency of the passband of the band-pass filter 100.
At least part of the partition 107 extends to pass between the resonator conductor portion 1520 and the resonator conductor portion 1560 and is in contact with the first portion 61 and the second portion 62. In the present embodiment, specifically, the partition 107 extends in the Z direction. The partition 107 connects the first portion 61 and the second portion 62 via the shortest path.
The partition 107 runs through the two or more dielectric layers constituting the main portion 21. In the present embodiment, the partition 107 includes a plurality of through hole lines 107T each running through the two or more dielectric layers constituting the main portion 21, and a conductor layer 107C. In
The connecting portion 63 of the shield 6 includes a plurality of through hole lines 163T each running through the two or more dielectric layers constituting the main portion 21. In
Reference is now made to
Further, a through hole 131T1 connected to the conductor layer 1311, and a through hole 131T2 connected to the conductor layer 1312 are formed in the dielectric layer 131. Further formed in the dielectric layer 131 are five through holes 107T1 constituting respective portions of the five through hole lines 107T, and a plurality of through holes 163T1 constituting respective portions of the plurality of through hole lines 163T. All the through holes represented by circles in
Five through holes 107T2 constituting respective portions of the five through hole lines 107T are further formed in each of the dielectric layers 132 to 134. The five through holes 107T1 shown in
Further formed in each of the dielectric layers 132 to 134 are a plurality of through holes 163T2 constituting respective portions of the plurality of through hole lines 163T. All the through holes represented by circles in
In the dielectric layers 132 to 134, every vertically adjacent through holes denoted by the same reference signs are connected to each other.
In the dielectric layer 135, there are formed a through hole 135T1 connected to a portion of the conductor layer 1351 near the second end thereof, and a through hole 135T2 connected to a portion of the conductor layer 1352 near the second end thereof.
Further formed in the dielectric layer 135 are five through holes 107T5 constituting respective portions of the five through hole lines 107T. The five through holes 107T2 formed in the fourth dielectric layer 134 are respectively connected to the five through holes 107T5.
Further formed in the dielectric layer 135 are a plurality of through holes 163T5 constituting respective portions of the plurality of through hole lines 163T. All the through holes represented by circles in
In each of the dielectric layers 136 to 139, there are further formed five through holes 107T6 constituting respective portions of the five through hole lines 107T. The five through holes 107T5 shown in
Further, a plurality of through holes 163T6 constituting respective portions of the plurality of through hole lines 163T are formed in each of the dielectric layers 136 to 139. All the through holes represented by circles in
In the dielectric layers 136 to 139, every vertically adjacent through holes denoted by the same reference signs are connected to each other.
The resonator conductor portion 1510 has a first end 151a and a second end 151b which are opposite ends of the conductor line. The resonator conductor portion 1520 has a first end 152a and a second end 152b which are opposite ends of the conductor line. The resonator conductor portion 1530 has a first end 153a and a second end 153b which are opposite ends of the conductor line. The resonator conductor portion 1540 has a first end 154a and a second end 154b which are opposite ends of the conductor line. The resonator conductor portion 1550 has a first end 155a and a second end 155b which are opposite ends of the conductor line. The resonator conductor portion 1560 has a first end 156a and a second end 156b which are opposite ends of the conductor line. The resonator conductor portion 1570 has a first end 157a and a second end 157b which are opposite ends of the conductor line.
The thick arrows in
As shown in
As shown in
The through hole 136T1 formed in the ninth dielectric layer 139 is connected to the narrow portion 151A of the resonator conductor portion 1510. The through hole 136T2 formed in the ninth dielectric layer 139 is connected to the narrow portion 157A of the resonator conductor portion 1570.
The resonator conductor portions 1520 and 1560 each extend in the Y direction. The resonator conductor portions 1520 and 1560 are adjacent to each other in the X direction and located at a predetermined distance from each other. The distance between the resonator conductor portions 1520 and 1560 is sufficiently smaller than the length of each of the resonator conductor portions 1520 and 1560.
As shown in
The narrow portion 152A has a width W152A, the first wide portion 152B has a width W152B, and the second wide portion 152C has a width W152C, each of the widths W152A, W152B and W152C being constant regardless of position in the Y direction. The width W152A is smaller than the widths W152B and W152C. The width W152C is greater than the width W152B. The coupling portions 152D and 152E vary in width depending on the position in the Y direction. The width of the coupling portion 152D is equal to that of the narrow portion 152A at the boundary between the coupling portion 152D and the narrow portion 152A, and equal to that of the first wide portion 152B at the boundary between the coupling portion 152D and the first wide portion 152B. The width of the coupling portion 152E is equal to that of the narrow portion 152A at the boundary between the coupling portion 152E and the narrow portion 152A, and equal to that of the second wide portion 152C at the boundary between the coupling portion 152E and the second wide portion 152C.
As shown in
The narrow portion 156A has a width W156A, the first wide portion 156B has a width W156B, and the second wide portion 156C has a width W156C, each of the widths W156A, W156B and W156C being constant regardless of position in the Y direction. The width W156A is smaller than the widths W156B and W156C. The width W156C is greater than the width W156B. The coupling portions 156D and 156E vary in width depending on the position in the Y direction. The width of the coupling portion 156D is equal to that of the narrow portion 156A at the boundary between the coupling portion 156D and the narrow portion 156A, and equal to that of the first wide portion 156B at the boundary between the coupling portion 156D and the first wide portion 156B. The width of the coupling portion 156E is equal to that of the narrow portion 156A at the boundary between the coupling portion 156E and the narrow portion 156A, and equal to that of the second wide portion 156C at the boundary between the coupling portion 156E and the second wide portion 156C.
As shown in
As shown in
The first end 153a of the resonator conductor portion 1530 and the first end 155a of the resonator conductor portion 1550 are adjacent to each other and located at a predetermined distance from each other.
The resonator conductor portion 1540 extends in the X direction. The first end 154a is located near the second end 153b of the resonator conductor portion 1530. The second end 154b is located near the second end 155b of the resonator conductor portion 1550. The resonator conductor portion 1540 has a width W154, the width W154 being constant between the first end 154a and the second end 154b.
Now, components formed on/in the dielectric layer 140 other than the resonator conductor portions 1510, 1520, 1530, 1540, 1550, 1560 and 1570 will be described with reference to
Further, five through holes 107T10 constituting respective portions of the five through hole lines 107T are formed in the dielectric layer 140. The five through holes 107T10 are connected to the conductor layer 107C. The five through holes 107T6 formed in the ninth dielectric layer 139 are respectively connected to the five through holes 107T10.
Further formed in the dielectric layer 140 are a plurality of through holes 163T10 constituting respective portions of the plurality of through hole lines 163T. All the through holes represented by circles in
Further, five through holes 107T11 constituting respective portions of the five through hole lines 107T are formed in the dielectric layer 141. The five through holes 107T10 shown in
Further formed in the dielectric layer 141 are a plurality of through holes 163T11 constituting respective portions of the plurality of through hole lines 163T. All the through holes represented by circles in
Further, a plurality of through holes 163T12 constituting respective portions of the plurality of through hole lines 163T are formed in each of the dielectric layers 142 to 148. All the through holes represented by circles in
In the dielectric layers 142 to 148, every vertically adjacent through holes denoted by the same reference signs are connected to each other.
The band-pass filter 100 according to the present embodiment is formed by stacking the first to nineteenth dielectric layers 131 to 149 such that the patterned surface of the first dielectric layer 131 also serves as the first end face 2A of the main body 2. A surface of the nineteenth dielectric layer 149 opposite from the patterned surface serves as the second end face 2B of the main body 2. The first to nineteenth dielectric layers 131 to 149 constitute the multilayer stack 20.
The respective resonator conductor portions 1510, 1520, 1530, 1540, 1550, 1560 and 1570 of the resonators 151 to 157 are located at the same position in the Z direction within the multilayer stack 20.
The conductor layer 1311 forming the first input/output port 3 is connected to the narrow portion 151A of the resonator conductor portion 1510 shown in
The conductor layer 1312 forming the second input/output port 4 is connected to the narrow portion 157A of the resonator conductor portion 1570 shown in
The conductor layer 1411 shown in
The conductor layer 1412 shown in
The conductor layer 1413 shown in
The conductor layer 1414 shown in
The conductor layer 1415 shown in
The conductor layer 1416 shown in
Each of the five through hole lines 107T of the partition 107 is formed by connecting the through holes 107T1, 107T2, 107T5, 107T6, 107T10, 107T11 and 107T12 in series in the Z direction.
In the example shown in
Each of the plurality of through hole lines 163T of the connecting portion 63 is formed by connecting the through holes 163T1, 163T2, 163T5, 163T6, 163T10, 163T11 and 163T12 in series in the Z direction.
In the present embodiment, N is an integer greater than or equal to 5, and is specifically 7. Further, in the present embodiment the fourth stage resonator 154 is the middle resonator. The N resonators in the present embodiment includes a first pair of first and second resonators and a second pair of first and second resonators. The first resonator of the first pair of first and second resonators is the first stage resonator 151. The second resonator of the first pair of first and second resonators is the N-th stage resonator, i.e., the seventh stage resonator 157. The first resonator of the second pair of first and second resonators is the second stage resonator 152. The second resonator of the second pair of first and second resonators is the N−1-th stage resonator, i.e., the sixth stage resonator. The resonator conductor portions 1510 and 1520 each correspond to the first resonator conductor portion. The resonator conductor portions 1560 and 1570 each correspond to the second resonator conductor portion.
In the present embodiment, there are three third resonators. Specifically, the third to fifth stage resonators 153, 154 and 155 are the third resonators. The resonator conductor portions 1530, 1540 and 1550 each correspond to the third resonator conductor portion.
As described previously, each of the resonator conductor portions 1510, 1520, 1560 and 1570 includes the narrow portion, the first wide portion, and the second wide portion. The resonators 151, 152, 156 and 167 are thus SIRs.
Each of the resonator conductor portions 1530, 1540 and 1550 includes no portion having a width smaller than the width at each of the first end and the second end. In the present embodiment, in particular, each of the resonator conductor portions 1530, 1540 and 1550 has a width constant between the first end and the second end. None of the resonators 153, 154 and 155 are SIRs.
The resonators 151, 152, 156 and 157 are each lower in unloaded Q than the resonators 153, 154 and 155.
The shortest paths 152P and 156P of the resonator conductor portions 1520 and 1560 are each smaller in length than the shortest paths 153P, 154P and 155P of the resonator conductor portions 1530, 1540 and 1550.
According to the present embodiment, since the resonators 151, 152, 156 and 157 configured as SIRs can achieve size reduction, it becomes possible to miniaturize the band-pass filter 100. Further, according to the present embodiment, since only the resonators 151, 152, 156 and 157 are configured as SIRs, it is possible to reduce an increase in insertion loss of the band-pass filter 100.
An example of unloaded Qs of the resonators 151 to 157 of the present embodiment will now be shown. In this example, the first and seventh stage resonators 151 and 157 have an unloaded Q of 182. The second and sixth stage resonators 152 and 156 have an unloaded Q of 206. The third and fifth stage resonators 153 and 155 have an unloaded Q of 235. The fourth stage resonator 154 has an unloaded Q of 247. Thus, in this example, each of the first, second, sixth and seventh stage resonators 151, 152, 156 and 157 is lower in unloaded Q than the third to fifth stage resonators 153 to 155.
Next, a description will be given of the results of a simulation on the band-pass filter 100 according to the present embodiment. The simulation determined the frequency response of insertion loss for each of first to fourth models of the band-pass filter 100. The first to fourth models have different combinations of unloaded Qs of the resonators 151 to 157.
In the first model, all the resonators 151 to 157 have an unloaded Q of 200. In the second model, the resonators 151 and 157 have an unloaded Q of 100, and the resonators 152 to 156 have an unloaded Q of 200. In the third model, the resonators 152 and 156 have an unloaded Q of 100, and the resonators 151, 153, 154, 155 and 157 have an unloaded Q of 200. In the fourth model, the resonators 153 and 155 have an unloaded Q of 100, and the resonators 151, 152, 154, 156 and 157 have an unloaded Q of 200.
The center frequency of the passband of each of the first to fourth models is approximately 26 GHz. As shown in
The configuration, operation and effects of the present embodiment are otherwise the same as those of the first embodiment.
The present invention is not limited to the foregoing embodiments, and various modifications may be made thereto. For example, the number and the configuration of the resonators are not limited to those illustrated in the foregoing embodiments, and can be freely chosen as far as the requirements of the appended claims are met.
Obviously, many modifications and variations of the present invention are possible in the light of the above teachings. Thus, it is to be understood that, within the scope of the appended claims and equivalents thereof, the invention may be practiced in other embodiments than the foregoing most preferable embodiments.
| Number | Date | Country | Kind |
|---|---|---|---|
| JP2018-186861 | Oct 2018 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 20130049894 | Hendry | Feb 2013 | A1 |
| Number | Date | Country |
|---|---|---|
| 2003-069306 | Mar 2003 | JP |
| 2006-311100 | Nov 2006 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20200106148 A1 | Apr 2020 | US |
