JP4155883B2 - Multilayer bandpass filter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multilayer bandpass filter having a balanced output end.
[0002]
[Prior art]
In wireless communication devices such as mobile phones, there is a strong demand for downsizing and thinning, so high-density component mounting technology is required. Thus, it has also been proposed to integrate components using a multilayer substrate.
[0003]
By the way, one of the components in a wireless communication device is a band-pass filter that filters a received signal. As this band-pass filter, as described in Patent Document 1, for example, a multilayer band-pass filter is known. This multilayer band-pass filter includes a resonator configured using a conductor layer in a multilayer substrate.
[0004]
By the way, the conventional multilayer bandpass filter inputs and outputs unbalanced signals with the ground potential as a reference potential. Therefore, in order to provide the output signal of this bandpass filter to a balanced input type amplifier, a balun that converts the unbalanced signal into a balanced signal composed of two signals that are approximately 180 ° out of phase and substantially equal in amplitude. (Unbalanced-balanced converter) was required. This balun can also be configured using a conductor layer in a multilayer substrate.
[0005]
Conventionally, the bandpass filter and the balun are configured as separate circuits. Patent Document 1 describes a multilayer dielectric filter in which a filter and a balun are integrated using a multilayer substrate.
[0006]
Patent Document 2 discloses a dielectric filter that can input and output a balanced signal without using a balun. This dielectric filter is coupled to a half-wave resonator whose both ends are open or short-circuited, a quarter-wave resonator whose one end is short-circuited and the other end is open, and a quarter-wave resonator. It has a balanced terminal and two balanced terminals that are respectively coupled near the two open ends of the half-wave resonator.
[0007]
[Patent Document 1]
JP 2003-87008 A
[Patent Document 2]
JP 2000-349505 A
[0008]
[Problems to be solved by the invention]
When the band-pass filter and the balun are configured as separate circuits, the number of parts increases, and there is a problem that the loss and size of the circuit including the band-pass filter and the balun increase. In the multilayer dielectric filter described in Patent Document 1, the filter and the balun are integrated using a multilayer substrate, but the filter and the balun are separate circuits. It is not solved.
[0009]
In the dielectric filter described in Patent Document 2, the two balanced terminals are arranged at positions away from the half-wave resonator, and the capacitance generated between the half-wave resonator and the balanced terminal is respectively reduced. To the half-wave resonator. In this configuration, the resonance frequency of the half-wave resonator changes depending on the size of the capacitance. Therefore, this configuration has a problem that it is difficult to adjust the characteristics of the filter.
[0010]
The present invention has been made in view of such problems, and an object of the present invention is to provide a multilayer bandpass filter that can output a balanced signal, is small, and can be easily adjusted.
[0011]
[Means for Solving the Problems]
The first multilayer bandpass filter of the present invention is
An unbalanced input terminal for inputting an unbalanced signal;
Two balanced output terminals for outputting balanced signals;
A plurality of resonators each consisting of a TEM line, a bandpass filter unit provided between the unbalanced input end and the balanced output end;
A multi-layer substrate for integrating a plurality of resonators,
The band-pass filter unit includes a half-wave resonator for balanced output composed of a half-wave resonator with both ends open as a resonator,
The balanced output terminal is directly connected to the half-wave resonator for balanced output.
[0012]
In the first multilayer bandpass filter of the present invention, two balanced output ends are directly connected to a balanced output half-wave resonator composed of a half-wave resonator open at both ends. Thereby, according to the first multilayer bandpass filter, a balanced signal can be output from the two balanced output terminals without providing a balun. In the present application, “directly connected” means that the two connected are physically continuous as conductors.
[0013]
In the first multilayer bandpass filter of the present invention, one balanced output end is directly connected to one half of the longitudinal direction of the half-wave resonator for balanced output, and the other balanced output end is The half-wave resonator for balanced output may be directly connected to the other half of the longitudinal direction. In this case, the two balanced output terminals may be connected to the balanced output half-wave resonator at a position asymmetric with respect to the longitudinal center of the balanced output half-wave resonator.
[0014]
The first multilayer bandpass filter of the present invention is further connected to the balanced output half-wave resonator in the vicinity of the center in the longitudinal direction of the balanced output half-wave resonator. You may provide the terminal for DC voltage application used in order to apply a DC voltage to a 1/2 wavelength resonator.
[0015]
In the first multilayer bandpass filter of the present invention, at least one of the plurality of resonators may have a shape in which the capacitance or inductance is larger than that of a rectangular shape. Good.
[0016]
Further, in the first multilayer bandpass filter of the present invention, both ends of at least one open half-wave resonator included in the bandpass filter unit may be connected via a capacitor.
[0017]
The second multilayer bandpass filter of the present invention is
An unbalanced input terminal for inputting an unbalanced signal;
Two balanced output terminals for outputting balanced signals;
A plurality of resonators each consisting of a TEM line, a bandpass filter unit provided between the unbalanced input end and the balanced output end;
A multi-layer substrate for integrating a plurality of resonators,
The band-pass filter unit is composed of a half-wave resonator for balanced output consisting of a half-wave resonator with open ends and a half-wave resonator for each of the quarter-wave resonators. A pair of 1/4 wavelength resonators between the output device and the balanced output end, and a balanced output 1/4 wavelength resonator provided with one or more stages,
Each balanced output terminal is directly connected to each of a pair of balanced output quarter wavelength resonators in the final stage.
[0018]
The second laminated band-pass filter of the present invention includes a balanced output 1/2 wavelength resonator composed of a 1/2 wavelength resonator open at both ends, the balanced output 1/2 wavelength resonator, and a balanced output end. And one or more stages of 1/4 wavelength resonators for balanced output provided between the two balanced output terminals are directly connected to each of the pair of 1/4 wavelength resonators for balanced output of the final stage. Yes. Thereby, according to the 2nd lamination type band pass filter, a balanced signal can be outputted from two balanced output terminals, without providing a balun.
[0019]
In the second laminated bandpass filter of the present invention, as the balanced output quarter wavelength resonator, only a pair of balanced output quarter wavelength resonators in the final stage may be provided. One of the pair of balanced output quarter wavelength resonators in the final stage is coupled to one half of the longitudinal direction in the balanced output half wavelength resonator, The other of the balanced output quarter-wave resonators may be coupled to the other half of the balanced output half-wave resonator in the longitudinal direction.
[0020]
The pair of quarter-wave resonators for balanced output at the final stage may be coupled to the half-wave resonator for balanced outputs by the same coupling method. One of the pair of balanced output quarter-wave resonators in the final stage is coupled only to one half of the longitudinal direction of the balanced output half-wave resonator in the pair of balanced outputs. The other of the quarter-wave resonators may be coupled only to the other half of the half-wave resonator for balanced output in the longitudinal direction.
[0021]
In the second multilayer bandpass filter of the present invention, the balanced output quarter wavelength resonator is provided in a plurality of stages, and the first stage pair of balanced outputs closest to the balanced output half wavelength resonator. One of the output 1/4 wavelength resonators is coupled to one half of the half length of the balanced output 1/2 wavelength resonator in the longitudinal direction, and the pair of balanced output 1/4 wavelength resonators in the first stage. The other of the resonators may be coupled to the other half portion in the longitudinal direction of the half-wave resonator for balanced output.
[0022]
The pair of balanced output 1/4 wavelength resonators in the first stage may be coupled to the balanced output 1/2 wavelength resonator by the same coupling method. One of the pair of balanced output quarter wavelength resonators in the first stage is coupled only to one half of the longitudinal direction in the balanced output half wavelength resonator. The other of the pair of balanced output quarter-wave resonators may be coupled only to the other half portion in the longitudinal direction of the balanced output half-wave resonator. The pair of balanced output quarter-wave resonators at each stage may be coupled to the pair of balanced output quarter-wave resonators at the front stage or the rear stage by the same coupling method.
[0023]
In the second multilayer bandpass filter of the present invention, at least one of the plurality of resonators may have a shape in which the capacitance or inductance is larger than that of a rectangular shape. Good.
[0024]
In the second multilayer bandpass filter of the present invention, both ends of at least one half-wave resonator with both ends open included in the bandpass filter section may be connected via a capacitor.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[First Embodiment]
First, the basic configuration of the multilayer bandpass filter according to the first embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, the multilayer bandpass filter 1 according to the present embodiment includes one unbalanced input terminal 2 that inputs an unbalanced signal and two balanced output terminals 3A and 3B that output a balanced signal. And a band-pass filter unit 4 provided between the unbalanced input terminal 2 and the balanced output terminals 3A and 3B. The band pass filter unit 4 includes a plurality of resonators 40 each formed of a TEM line. The multilayer bandpass filter 1 further includes a multilayer substrate on which a plurality of resonators 40 are integrated.
[0026]
The TEM line is a transmission line that transmits a TEM wave (Transverse Electromagnetic Wave) that is an electromagnetic wave in which both an electric field and a magnetic field exist only in a cross section perpendicular to the traveling direction of the electromagnetic wave.
[0027]
As will be described in detail later, the multilayer substrate has a structure in which dielectric layers and patterned conductor layers are alternately stacked. Each resonator 40 is configured using a conductor layer of the multilayer substrate. Each resonator 40 is a distributed constant line.
[0028]
The resonance frequencies of the plurality of resonators 40 constituting the band pass filter unit 4 are equal. The plurality of resonators 40 are arranged so that adjacent ones are electromagnetically coupled. Thereby, the plurality of resonators 40 exhibit a function as a band-pass filter that selectively allows a signal having a frequency within a predetermined frequency band to pass therethrough.
[0029]
As each resonator 40, any one of a half-wave resonator with both ends open, a half-wave resonator with both ends short-circuited, and a quarter-wave resonator can be used.
[0030]
FIG. 2 shows a half-wave resonator 41 having both ends open, and an electric field distribution in the resonator 41. As shown in FIG. 2, in this resonator 41, the electric field is zero at the center in the longitudinal direction, and the electric field is maximum at both ends. In one half of the resonator 41 in the longitudinal direction, the electric field has the same phase at all points. Similarly, the phase of the electric field is the same at all points in the other half of the resonator 41 in the longitudinal direction. In one half portion and the other half portion, the phase of the electric field differs by 180 °, and the signs of the electric fields are opposite to each other.
[0031]
FIG. 3 shows a half-wave resonator 42 with both ends short-circuited and an electric field distribution in the resonator 42. As shown in FIG. 3, in this resonator 42, the electric field becomes maximum at the center in the longitudinal direction, and the electric field becomes zero at both ends.
[0032]
FIG. 4 shows a quarter wavelength resonator 43 and an electric field distribution in the resonator 43. As shown in FIG. 4, in this resonator 43, one end is short-circuited and the other end is opened. In the resonator 43, the electric field becomes zero at the shorted end, and the electric field becomes maximum at the opened end.
[0033]
In the present embodiment, the bandpass filter unit 4 includes a balanced output half-wave resonator 41 </ b> A including a half-wave resonator 41 having both ends open as the resonator 40. The balanced output terminal 3A is directly connected to one half of the half-wave resonator 41A for balanced output in the longitudinal direction, and the balanced output terminal 3B is connected to the half-wave resonator 41A for balanced output. It is directly connected to the other half in the longitudinal direction.
[0034]
Further, the unbalanced input terminal 2 is connected to an input resonator 40I which is a resonator 40 disposed at a position closest to the unbalanced input terminal 2.
[0035]
Next, with reference to FIG. 5, the operation of the multilayer bandpass filter 1 according to the present embodiment will be described. An unbalanced signal is input to the unbalanced input terminal 2 of the multilayer bandpass filter 1. Among these signals, a signal having a frequency within a predetermined frequency band selectively passes through the band-pass filter unit 4. The final-stage resonator 40 of the bandpass filter unit 4 is a balanced output half-wave resonator 41A including a half-wave resonator 41 having both ends open. In this resonator 41A, as described with reference to FIG. 2, the phase of the electric field differs by 180 ° in one half portion and the other half portion in the longitudinal direction. The balanced output terminal 3A is connected to one half of the resonator 41A, and the balanced output terminal 3B is connected to the other half of the resonator 41A. Therefore, the voltages output from the balanced output terminals 3A and 3B are always 180 ° out of phase with each other. Therefore, by providing the balanced output terminals 3A and 3B at positions where the amplitudes of the two voltages output from the balanced output terminals 3A and 3B are equal, a balanced signal can be output from the balanced output terminals 3A and 3B. .
[0036]
Here, as shown in FIG. 5, the position where the balanced output end 3A is connected in the resonator 41A is a position away from the center C in the longitudinal direction of the resonator 41A by one distance side from the end x, A position where the balanced output end 3B is connected in the resonator 41A is a position separated from the center C in the longitudinal direction of the resonator 41A by the distance xb from the other end side. The distances xa and xb are both greater than zero. As the distances xa and xb increase, the amplitude of the voltage output from the balanced output terminals 3A and 3B increases.
[0037]
In the case where the electric field distribution is symmetric between one half and the other half of the resonator 41A, the distances of the two voltages output from the balanced output terminals 3A and 3B are equal to each other. What is necessary is just to make xa and xb equal. However, the electric field distribution may not be symmetric between one half and the other half of the resonator 41A because the unbalanced input terminal 2 is connected to the input resonator 40I. In this case, the distances xa and xb for equalizing the amplitudes of the two voltages output from the balanced output terminals 3A and 3B are not equal. That is, the balanced output ends 3A and 3B are connected to the resonator 41A at a position asymmetric with respect to the center C in the longitudinal direction of the resonator 41A.
[0038]
Next, a method for connecting the unbalanced input terminal 2 to the input resonator 40I will be described. There are mainly the following two methods for connecting the unbalanced input terminal 2 to the input resonator 40I. The first method is a method of connecting the unbalanced input terminal 2 to the input resonator 40I through a capacitor. The second method is a method of directly connecting the unbalanced input terminal 2 to the input resonator 40I without using a capacitor. Hereinafter, these two methods will be described in order with reference to FIG. 6 and FIG.
[0039]
First, the first method will be described with reference to FIG. In the first method, as shown in FIG. 6, the unbalanced input terminal 2 is connected to the input resonator 40I through the capacitor 21. In FIG. 6, a signal source 22 is connected to the unbalanced input terminal 2. In the first method, as the capacitance of the capacitor 21 is reduced, the coupling between the unbalanced input terminal 2 and the input resonator 40I is weakened. As the capacitance of the capacitor 21 is increased, the unbalanced input terminal 2 and the input resonance are reduced. Coupling with the container 40I is strengthened. However, the larger the capacitance of the capacitor 21, the lower the resonance frequency of the input resonator 40I. Therefore, in the case of using the first method, in order to obtain a desired resonance frequency in the input resonator 40I, the length of the input resonator 40I is expected with the expectation that the resonance frequency is lowered by the capacitor 21. It is necessary to adjust the resonance frequency by reducing the frequency.
[0040]
Next, the second method will be described. In the second method, the unbalanced input terminal 2 is directly connected to the input resonator 40I. Here, a case where the second method is used when the input resonator 40I is the quarter wavelength resonator 43 will be described with reference to FIG. In FIG. 7, a signal source 22 is connected to the unbalanced input terminal 2. In FIG. 7, the input resonator 40I includes a first portion 40Ia from the position where the unbalanced input end 2 is connected to the short-circuited end, and a second portion from the position where the unbalanced input end 2 is connected to the open end. It is divided into a portion 40Ib. The ratio between the length of the first portion 40Ia and the length of the second portion 40Ib is x: (10−x). Note that x is greater than 0 and equal to or less than 10. In this case, the smaller the value of x, the weaker the coupling between the unbalanced input terminal 2 and the input resonator 40I, and the larger the value of x, the coupling between the unbalanced input terminal 2 and the input resonator 40I. Become stronger. In the second method, changing the value of x does not change the resonance frequency of the input resonator 40I.
[0041]
Next, a case where the second method is used when the input resonator 40I is a half-wave resonator will be described. First, when the input resonator 40I is the open-ended half-wavelength resonator 41 shown in FIG. 2, the position where the unbalanced input end 2 is connected to the input resonator 40I is the length of the input resonator 40I. The closer to the center of the direction, the weaker the coupling between the unbalanced input terminal 2 and the input resonator 40I becomes. The coupling between the unbalanced input terminal 2 and the input resonator 40I becomes strong. In this case, even if the position where the unbalanced input terminal 2 is connected to the input resonator 40I is changed, the resonance frequency of the input resonator 40I does not change.
[0042]
Further, when the input resonator 40I is the half-wave resonator 42 with both ends short-circuited as shown in FIG. 3, the position where the unbalanced input terminal 2 is connected to the input resonator 40I is short-circuited with the input resonator 40I. The closer to the end, the weaker the coupling between the unbalanced input end 2 and the input resonator 40I becomes. The coupling between the unbalanced input terminal 2 and the input resonator 40I becomes strong. In this case, even if the position where the unbalanced input terminal 2 is connected to the input resonator 40I is changed, the resonance frequency of the input resonator 40I does not change.
[0043]
As described above, in the second method, the strength of coupling between the unbalanced input terminal 2 and the input resonator 40I can be changed without adjusting the length of the input resonator 40I.
[0044]
Hereinafter, first to fourth examples of the specific configuration of the multilayer bandpass filter 1 according to the present embodiment will be described.
[0045]
[First configuration example]
FIG. 8 is a circuit diagram of the multilayer bandpass filter 1 of the first configuration example. The multilayer bandpass filter 1 includes an unbalanced input end 2, balanced output ends 3A and 3B, and a bandpass filter unit 4 provided between the unbalanced input end 2 and the balanced output ends 3A and 3B. I have. The band-pass filter unit 4 is composed of half-wave resonators 41 that are open at both ends, and has three resonators 40 arranged side by side. Of the three resonators 40, the resonator 40 disposed at the position closest to the unbalanced input end 2 is an input resonator 40I. The unbalanced input terminal 2 is directly connected to the input resonator 40I. Further, the resonator 40 arranged at a position closest to the balanced output terminals 3A and 3B is a balanced output ½ wavelength resonator 41A. The balanced output terminals 3A and 3B are directly connected to the balanced output ½ wavelength resonator 41A. Hereinafter, the resonator 40 disposed between the resonator 40I and the resonator 41A is referred to as an intermediate resonator 40M. The input resonator 40I and the intermediate resonator 40M are electromagnetically coupled, and the intermediate resonator 40M and the balanced output half-wave resonator 41A are also electromagnetically coupled. A capacitor C is provided between the open ends of the three resonators 40 and the ground.
[0046]
FIG. 9 is an exploded perspective view illustrating an example of the configuration of the multilayer substrate 30 that realizes the multilayer bandpass filter 1 illustrated in FIG. 8. In this example, the multilayer substrate 30 includes seven dielectric layers 31a to 31g that are sequentially stacked from the bottom. A ground conductor layer 32 that also serves as a shield is formed on the upper surface of the dielectric layer 31b. On the upper surface of the dielectric layer 31c, an input resonator 40I, an intermediate resonator 40M, and a balanced output half-wave resonator 41A are formed. Terminal conductor layers 33A and 33B that are directly connected to the balanced output half-wave resonator 41A are further formed on the upper surface of the dielectric layer 31c. The ends of the terminal conductor layers 33A and 33B opposite to the resonator 41A are balanced output ends 3A and 3B.
[0047]
Six through holes 34 are formed on the upper surface of the dielectric layer 31d at positions corresponding to both ends of the resonators 40I, 40M, and 41A. On the top surface of the dielectric layer 31d, a terminal conductor layer 35 connected to the through hole 34 disposed at a position corresponding to one end of the resonator 40I is further formed. The end of the terminal conductor layer 35 opposite to the through hole 34 is the unbalanced input end 2.
[0048]
On the upper surface of the dielectric layer 31e, six capacitor conductor layers 36 and six through holes 37 connected thereto are formed at positions corresponding to the six through holes 34. Each capacitor conductor layer 36 is connected to each end of the resonators 40I, 40M, and 41A via through holes 34 and 37, respectively. A ground conductor layer 38 that also serves as a shield is formed on the upper surface of the dielectric layer 31f. The capacitor C in FIG. 8 is formed by a capacitor conductor layer 36 and a ground conductor layer 38.
[0049]
FIG. 10 is a perspective view showing an example of the appearance of the multilayer substrate 30 shown in FIG. In this example, a plurality of terminal electrodes 39 are formed on the upper surface, lower surface and side surfaces of the multilayer substrate 30. The terminal electrode 39 is connected to a conductor layer inside the multilayer substrate 30 and is used for connection between the conductor layer and an external device.
[0050]
The multilayer substrate 30 is, for example, a low-temperature fired ceramic multilayer substrate. In this case, the multilayer substrate 30 is manufactured as follows, for example. That is, first, a conductive layer having a predetermined pattern is formed on a ceramic green sheet in which holes for through holes have been formed in advance using, for example, a conductive paste mainly composed of silver. Next, a plurality of ceramic green sheets on which the conductor layers are thus formed are laminated and fired at the same time. Thereby, a through hole is simultaneously formed. Next, the terminal electrode 39 is formed, and the multilayer substrate 30 is completed.
[0051]
In the multilayer bandpass filter 1 of the first configuration example, since the bandpass filter unit 4 is configured by arranging three resonators 40 each of which is a half-wavelength resonator 41 having both ends open, Balance is good. Further, in this multilayer bandpass filter 1, since the capacitors C are provided between the open ends of the resonators 40 and the ground, the resonators having a desired resonance frequency compared to the case where the capacitors C are not provided. The physical length of 40 can be reduced.
[0052]
[Second Configuration Example]
FIG. 11 is a circuit diagram of the multilayer bandpass filter 1 of the second configuration example. This multilayer bandpass filter 1 is the first one shown in FIG. 1 A DC voltage application terminal 5 is added to the multilayer bandpass filter 1 of the configuration example. The DC voltage application terminal 5 is connected to the balanced output 1/2 wavelength resonator 41A in the vicinity of the center in the longitudinal direction of the balanced output 1/2 wavelength resonator 41A. The DC voltage application terminal 5 is used to apply a DC voltage to the balanced output half-wave resonator 41A. This DC voltage is used, for example, to drive an integrated circuit connected to the balanced output terminals 3A and 3B.
[0053]
FIG. 12 is an exploded perspective view illustrating an example of the configuration of the multilayer substrate 30 that realizes the multilayer bandpass filter 1 illustrated in FIG. 11. In this example, in the multilayer substrate 30, the terminal conductor layer 50 directly connected to the balanced output half-wave resonator 41A is formed on the upper surface of the dielectric layer 31c in the multilayer substrate 30 shown in FIG. Yes. An end of the terminal conductor layer 50 opposite to the resonator 41 </ b> A serves as a DC voltage application terminal 5.
[0054]
Other configurations of the multilayer bandpass filter 1 of the second configuration example are the same as those of the multilayer bandpass filter 1 of the first configuration example.
[0055]
[Third configuration example]
FIG. 13 is a circuit diagram of the multilayer bandpass filter 1 of the third configuration example. The multilayer bandpass filter 1 includes an unbalanced input end 2, balanced output ends 3A and 3B, and a bandpass filter unit 4 provided between the unbalanced input end 2 and the balanced output ends 3A and 3B. I have. The band pass filter unit 4 has three resonators 40 arranged side by side. Of the three resonators 40, the resonator 40 disposed at the position closest to the unbalanced input end 2 is an input resonator 40I. The unbalanced input terminal 2 is directly connected to the input resonator 40I. Further, the resonator 40 arranged at a position closest to the balanced output terminals 3A and 3B is a balanced output ½ wavelength resonator 41A. The balanced output terminals 3A and 3B are directly connected to the balanced output ½ wavelength resonator 41A. A quarter wavelength resonator 43 is used for the input resonator 40I and the intermediate resonator 40M. The input resonator 40I and the intermediate resonator 40M are electromagnetically coupled, and the intermediate resonator 40M and the balanced output half-wave resonator 41A are also electromagnetically coupled.
[0056]
FIG. 14 is an exploded perspective view showing an example of the configuration of the multilayer substrate 30 that realizes the multilayer bandpass filter 1 shown in FIG. 13. In this example, the multilayer substrate 30 includes five dielectric layers 51a to 51e that are sequentially stacked from the bottom. A ground conductor layer 52 that also serves as a shield is formed on the upper surface of the dielectric layer 51b. An input resonator 40I, an intermediate resonator 40M, and a balanced output half-wave resonator 41A are formed on the upper surface of the dielectric layer 51c. On the upper surface of the dielectric layer 51c, terminal conductor layers 53A and 53B directly connected to the balanced output half-wave resonator 41A and a terminal conductor layer 54 directly connected to the input resonator 40I are further provided. Is formed. The ends of the terminal conductor layers 53A and 53B opposite to the resonator 41A are balanced output ends 3A and 3B. The end of the terminal conductor layer 54 opposite to the resonator 40I is the unbalanced input end 2. A ground conductor layer 55 that also serves as a shield is formed on the upper surface of the dielectric layer 51d.
[0057]
The appearance of the multilayer substrate 30 in the third configuration example is the same as that of the multilayer substrate 30 in the first configuration example, for example. In the third configuration example, the quarter-wave resonator 43 is used as the input resonator 40I and the intermediate resonator 40M. Therefore, the multilayer bandpass filter 1 can be downsized as compared with the first configuration example. Can do.
[0058]
[Fourth configuration example]
FIG. 15 is a circuit diagram of the multilayer bandpass filter 1 of the fourth configuration example. The multilayer bandpass filter 1 includes an unbalanced input end 2, balanced output ends 3A and 3B, and a bandpass filter unit 4 provided between the unbalanced input end 2 and the balanced output ends 3A and 3B. I have. The band-pass filter unit 4 is composed of a half-wave resonator 41 that is open at both ends, and has two resonators 40 arranged side by side. The resonator 40 disposed near the unbalanced input end 2 is an input resonator 40I. The unbalanced input terminal 2 is directly connected to the input resonator 40I. The resonator 40 disposed at a position close to the balanced output ends 3A and 3B is a balanced output half-wave resonator 41A. The balanced output terminals 3A and 3B are directly connected to the balanced output ½ wavelength resonator 41A. The input resonator 40I and the balanced output half-wave resonator 41A are electromagnetically coupled. A capacitor C is provided between the open ends of the two resonators 40 and the ground. Further, a capacitor C <b> 1 is provided between one open ends of the two resonators 40. A capacitor C <b> 2 is provided between the other open ends of the two resonators 40.
[0059]
FIG. 16 is an exploded perspective view showing an example of the configuration of the multilayer substrate 30 that realizes the multilayer bandpass filter 1 shown in FIG. 15. In this example, the multilayer substrate 30 includes seven dielectric layers 61a to 61g that are sequentially stacked from the bottom. A ground conductor layer 62 that also serves as a shield is formed on the upper surface of the dielectric layer 61b. On the upper surface of the dielectric layer 61c, two capacitor conductor layers 63A, a conductor layer 64A connecting the two capacitor conductor layers 63A, two capacitor conductor layers 63B, and the two capacitor conductor layers A conductor layer 64B connecting 63B is formed.
[0060]
On the top surface of the dielectric layer 61d, an input resonator 40I and a balanced output half-wave resonator 41A are formed. The upper surface of the dielectric layer 61d is further connected to two capacitor conductor layers 65A connected to one end of each of the resonators 40I and 41A and to the other end of each of the resonators 40I and 41A. Two capacitor conductor layers 65B are formed. The two capacitor conductor layers 65A are arranged at positions facing the two capacitor conductor layers 63A. Similarly, the two capacitor conductor layers 65B are disposed at positions facing the two capacitor conductor layers 63B.
[0061]
Terminal conductor layers 66A and 66B directly connected to the balanced output half-wave resonator 41A are further formed on the upper surface of the dielectric layer 61d via the capacitor conductor layers 65A and 65B. The ends of the terminal conductor layers 66A and 66B opposite to the resonator 41A are balanced output ends 3A and 3B. A terminal conductor layer 67 directly connected to one end of the input resonator 40I is further formed on the upper surface of the dielectric layer 61d via the capacitor conductor layer 65A. The end of the terminal conductor layer 67 opposite to the input resonator 40I is the unbalanced input end 2.
[0062]
Two ground conductor layers 68A and two ground conductor layers 68B are formed on the upper surface of the dielectric layer 61e. The two ground conductor layers 68A are arranged at positions facing the two capacitor conductor layers 65A. Similarly, the two ground conductor layers 68B are disposed at positions facing the two capacitor conductor layers 65B. A ground conductor layer 69 that also serves as a shield is formed on the upper surface of the dielectric layer 61f.
[0063]
The capacitor C in FIG. 15 is formed by capacitor conductor layers 65A and 65B and ground conductor layers 68A and 68B. The capacitor C1 in FIG. 15 is formed of two capacitor conductor layers 65A, two capacitor conductor layers 63A, and a conductor layer 64A. Further, the capacitor C2 in FIG. 15 is formed by two capacitor conductor layers 65B, two capacitor conductor layers 63B, and a conductor layer 64B.
[0064]
The appearance of the multilayer substrate 30 in the fourth configuration example is the same as that of the multilayer substrate 30 in the first configuration example, for example. In the fourth configuration example, the capacitor C is provided between each open end of the resonator 40 and the ground. Therefore, compared to the case where the capacitor C is not provided, the physical structure of the resonator 40 having a desired resonance frequency is provided. Length can be reduced. In the fourth configuration example, a capacitor C1 is provided between one open ends of the two resonators 40, and a capacitor C2 is provided between the other open ends of the two resonators 40. These capacitors C 1 and C 2 have a function of forming an attenuation pole in the attenuation / insertion loss characteristics of the multilayer bandpass filter 1. In the fourth configuration example, since the bandpass filter unit 4 is configured by the two resonators 40, the insertion loss is small compared to the case where the bandpass filter unit 4 is configured by the three resonators 40. Become.
[0065]
Here, FIGS. 17 to 20 show examples of characteristics of the multilayer bandpass filter 1 of the first configuration example. FIG. 17 shows the attenuation / insertion loss characteristics of the multilayer bandpass filter 1. FIG. 18 shows the reflection loss characteristics of the multilayer bandpass filter 1. From FIG. 17 and FIG. 18, it can be seen that the multilayer bandpass filter 1 functions as a bandpass filter that selectively passes a signal having a frequency within a predetermined frequency band. FIG. 19 shows the frequency characteristic of the amplitude difference between the output signals of the balanced output terminals 3A and 3B of the multilayer bandpass filter 1. FIG. 20 shows the frequency characteristics of the phase difference between the output signals of the balanced output terminals 3A and 3B of the multilayer bandpass filter 1. FIG. 19 and 20, it can be seen that in this multilayer bandpass filter 1, a balanced signal is output from the balanced output terminals 3A and 3B.
[0066]
As described above, according to the multilayer bandpass filter 1 according to the present embodiment, it is possible to output a balanced signal composed of two signals whose phases are approximately 180 ° different from each other and whose amplitudes are approximately equal.
[0067]
Further, according to the multilayer bandpass filter 1 according to the present embodiment, a balanced signal can be output without using a balun. In the multilayer bandpass filter 1 according to the present embodiment, a plurality of resonators 40 are integrated by the multilayer substrate 30. For these reasons, according to the present embodiment, the multilayer bandpass filter 1 can be miniaturized.
[0068]
In the multilayer bandpass filter 1 according to the present embodiment, the balanced output terminals 3A and 3B are directly connected to the balanced output half-wave resonator 41A, so that the characteristics can be easily adjusted.
[0069]
[Second Embodiment]
Next, the basic configuration of the multilayer bandpass filter according to the second embodiment of the present invention will be described with reference to FIG. As shown in FIG. 21, the multilayer bandpass filter 71 according to the present embodiment includes one unbalanced input terminal 2 that inputs an unbalanced signal and two balanced output terminals 3A and 3B that output a balanced signal. And a band-pass filter unit 4 provided between the unbalanced input terminal 2 and the balanced output terminals 3A and 3B. The bandpass filter unit 4 has a plurality of resonators each formed of a TEM line. The multilayer bandpass filter 71 further includes a multilayer substrate for integrating a plurality of resonators. The resonance frequencies of the plurality of resonators constituting the bandpass filter unit 4 are equal. The plurality of resonators are arranged so that adjacent ones are electromagnetically coupled. Thus, the plurality of resonators exhibit a function as a band pass filter that selectively allows a signal having a frequency within a predetermined frequency band to pass therethrough.
[0070]
The bandpass filter unit 4 includes, as resonators, a balanced output ½ wavelength resonator 41A including a ½ wavelength resonator 41 having both ends open, a balanced output ½ wavelength resonator 41A, and a balanced output end 3A. , 3B, and 1/4 wavelength resonators 72A, 72B for balanced output. The balanced output quarter-wave resonators 72 </ b> A and 72 </ b> B are each composed of a quarter-wave resonator 43. The balanced output quarter-wave resonators 72A and 72B are provided in a plurality of stages, with the pair of resonators 72A and 72B as one stage. The balanced output terminals 3A and 3B are directly connected to the pair of balanced output quarter-wave resonators 72A and 72B at the final stage.
[0071]
The bandpass filter unit 4 may further include one or more resonators provided between the unbalanced input terminal 2 and the balanced output half-wave resonator 41A. As this resonator, any one of a half-wave resonator with both ends open, a half-wave resonator with both ends short-circuited, and a quarter-wave resonator can be used. FIG. 21 shows an example in which at least an input resonator 40I is provided between the unbalanced input terminal 2 and the balanced output half-wave resonator 41A. However, the unbalanced input terminal 2 is connected to the balanced output ½ wavelength resonator 41A without providing another resonator between the unbalanced input terminal 2 and the balanced output ½ wavelength resonator 41A. The balanced output half-wave resonator 41A may also serve as the input resonator 40I.
[0072]
The connection method of the unbalanced input terminal 2 to the input resonator 40I may be a method of connecting the unbalanced input terminal 2 to the input resonator 40I via a capacitor, as in the first embodiment, or via a capacitor. Instead, a method of directly connecting the unbalanced input terminal 2 to the input resonator 40I may be used.
[0073]
Next, the operation of the multilayer bandpass filter 71 according to this embodiment will be described. First, the operation of the multilayer bandpass filter 71 when only the final-stage balanced output quarter-wave resonators 72A and 72B are provided as the balanced-output quarter-wave resonators 72A and 72B will be described. . In this case, one resonator 72A is coupled to one half of the half-wave resonator 41A for balanced output in the longitudinal direction, and the other resonator 72B is a half-wave resonator 41A for balanced output. To the other half of the longitudinal direction.
[0074]
As described in the first embodiment, in the half-wave resonator for balanced output 41A, the phase of the electric field differs by 180 ° in one half portion and the other half portion in the longitudinal direction. Therefore, the phase of the electric field in the balanced output quarter-wave resonators 72A and 72B is also different by 180 °. Therefore, by providing the balanced output terminals 3A and 3B at positions where the amplitudes of the two voltages output from the balanced output terminals 3A and 3B are equal, a balanced signal can be output from the balanced output terminals 3A and 3B. .
[0075]
As described above, according to the multilayer bandpass filter 71 according to the present embodiment, a balanced signal can be output without using a balun, as in the first embodiment. In the multilayer bandpass filter 71 according to the present embodiment, a plurality of resonators 40 are integrated by the multilayer substrate 30. For these reasons, according to the present embodiment, the multilayer bandpass filter 71 can be downsized.
[0076]
In the multilayer bandpass filter 71 according to the present embodiment, the balanced output terminals 3A and 3B are directly connected to the balanced output quarter-wave resonators 72A and 72B, so that the characteristics can be easily adjusted. .
[0077]
Here, with reference to FIGS. 22 to 28, a method of coupling the balanced output quarter-wave resonators 72A and 72B with the balanced output half-wave resonator 41A will be described. As a method of coupling the two resonators, there are interdigital coupling and combline coupling. As shown in FIG. 22, the interdigital coupling means that the open end 301a of one resonator 301 and the short-circuited end 302b of the other resonator 302 face each other, and the short-circuited end 301b of one resonator 301 and the other In this coupling method, the resonators 301 and 302 are arranged so as to face the open end 302a of the resonator 302. As shown in FIG. 23, the comb line coupling means that the open end 301a of one resonator 301 and the open end 302a of the other resonator 302 face each other, and the short-circuited end 301b of one resonator 301 and the other end In this coupling method, the resonators 301 and 302 are arranged so as to face the short-circuited end 302b of the resonator 302. Interdigital coupling is stronger than combline coupling.
[0078]
As the coupling method between the balanced output quarter-wave resonators 72A and 72B and the balanced output half-wave resonator 41A, the three coupling methods shown in FIGS. In the coupling method shown in FIG. 24, both the balanced output quarter-wave resonators 72A and 72B are interdigitally coupled to the balanced output half-wave resonator 41A. In the coupling method shown in FIG. 25, both the balanced output quarter-wave resonators 72A and 72B are comb-line coupled to the balanced output half-wave resonator 41A. In the coupling method shown in FIG. 26, one of the balanced output 1/4 wavelength resonators 72A and 72B (resonator 72B in FIG. 26) is interdigitally coupled to the balanced output 1/2 wavelength resonator 41A. The other (resonator 72A in FIG. 26) is comb-line coupled to the balanced output half-wavelength resonator 41A.
[0079]
In the coupling method shown in FIG. 26, the balance of the amplitude of the balanced signal is deteriorated. Therefore, as shown in FIG. 24 or FIG. 25, the balanced output quarter wavelength resonators 72A and 72B are preferably coupled to the balanced output half wavelength resonator 41A by the same coupling method. .
[0080]
In addition, as shown in FIG. 27, one of the balanced output quarter-wave resonators 72A and 72B (resonator 72B in FIG. 27) is one in the longitudinal direction of the balanced output half-wave resonator 41A. If it is coupled to both the half portion 41Aa and the other half portion 41Ab, the balance of the balanced signal will be poor. Therefore, as shown in FIG. 28, the balanced output ¼ wavelength resonator 72A is coupled only to one half portion 41Aa in the longitudinal direction of the balanced output ½ wavelength resonator 41A. The quarter wavelength resonator 72B is preferably coupled only to the other half portion 41Ab in the longitudinal direction of the balanced output half wavelength resonator 41A.
[0081]
Next, the operation of the multilayer bandpass filter 1 in the case where a plurality of stages of 1/4 wavelength resonators 72A and 72B for balanced output are provided as the balanced output 1/4 wavelength resonators 72A and 72B will be described. . In this case, one of the first-stage pair of resonators 72A and 72B closest to the balanced output 1/2 wavelength resonator 71A is in the longitudinal direction of the balanced output 1/2 wavelength resonator 41A. The other resonator 72B is coupled to the other half portion in the longitudinal direction of the balanced output half-wave resonator 41A. The rear stage resonator 72A is coupled to the front stage resonator 72A, and the rear stage resonator 72B is coupled to the front stage resonator 72B.
[0082]
As described above, in the half-wave resonator for balanced output 41A, the phase of the electric field differs by 180 ° in one half portion and the other half portion in the longitudinal direction. Therefore, the phase of the electric field in the balanced output quarter-wave resonators 72A and 72B in each stage is also different by 180 °. Therefore, by providing the balanced output terminals 3A and 3B at positions where the amplitudes of the two voltages output from the balanced output terminals 3A and 3B are equal, a balanced signal can be output from the balanced output terminals 3A and 3B. .
[0083]
For the same reason as described with reference to FIGS. 24 to 26, the first-stage balanced output quarter-wave resonators 72A and 72B are coupled to the balanced output half-wave resonator 41A by the same coupling method. It is preferred that Further, for the same reason, as shown in FIG. 29 or FIG. 30, the pair of balanced output quarter-wave resonators 72A and 72B in each stage has a pair of balanced output 1/4 in the preceding stage or the subsequent stage. The wavelength resonators 72A and 72B are preferably coupled by the same coupling method. FIG. 29 shows a case where two adjacent stages of resonators 72A and resonators 72B are coupled together by comb line coupling. FIG. 30 shows a case where two adjacent stages of resonators 72A and resonators 72B are coupled together by interdigital coupling.
[0084]
For the same reason as described with reference to FIG. 27 and FIG. 28, the first-stage balanced output ¼ wavelength resonator 72A is half of the longitudinal direction of the balanced output ½ wavelength resonator 41A. Only the portion 41Aa is coupled, and the first-stage balanced output quarter wavelength resonator 72B is coupled only to the other half portion 41Ab in the longitudinal direction of the balanced output half wavelength resonator 41A. preferable.
[0085]
The configuration of the multilayer substrate 30 in the present embodiment includes, for example, one or more stages between the balanced output half-wave resonator 41A and the balanced output terminals 3A and 3B conductor layers in the first embodiment. The balanced output 1/4 wavelength resonators 72A and 72B are arranged. The appearance of the multilayer substrate 30 in the present embodiment is the same as that of the multilayer substrate 30 shown in FIG. 10, for example. Other configurations, operations, and effects in the present embodiment are the same as those in the first embodiment.
[0086]
[Third Embodiment]
Next, a multilayer bandpass filter according to a third embodiment of the present invention will be described with reference to FIGS. In the multilayer bandpass filter according to the present embodiment, in the multilayer bandpass filter according to the first or second embodiment, at least one of a plurality of resonators constituting the bandpass filter unit 4 is Compared to the case where the shape is a rectangle, the capacitance or inductance is increased.
[0087]
Hereinafter, four examples of specific shapes of the resonator according to the present embodiment will be described.
[0088]
[First example of resonator shape]
FIG. 31 is an explanatory diagram showing the resonator 101 of the first example and a rectangular resonator 102 for comparison with the resonator 101. The resonators 101 and 102 are both half-wave resonators that are open at both ends. The resonance frequencies of the resonators 101 and 102 are equal. In the resonator 101, the width of the two portions 101a and 101b near the open end is larger than the width of the portion 101c between the portions 101a and 101b. The width of the portion 101 c is equal to the width of the resonator 102. In the resonator 101, the capacitance near the open end is larger than that in the resonator 102. As a result, the physical length of the resonator 101 is smaller than the physical length of the resonator 102.
[0089]
FIG. 32 is an exploded perspective view showing an example of the configuration of the multilayer substrate 30 that realizes the resonator 101 shown in FIG. 31. FIG. 32 shows only a portion of the multilayer substrate 30 in the vicinity of the resonator 101. The multilayer substrate 30 shown in FIG. 32 has nine dielectric layers 111a to 111i that are sequentially stacked from the bottom. A ground conductor layer 112 is formed on the upper surface of the dielectric layer 111b. A conductor layer 113 that is long in one direction is formed on the upper surface of the dielectric layer 111c. A ground conductor layer 114 and two through holes 115 are formed on the upper surface of the dielectric layer 111d. The through hole 115 is not in contact with the ground conductor layer 114. On the upper surface of the dielectric layer 111e, two capacitor conductor layers 116a and 116b and two through holes 117 connected to the capacitor conductor layers 116a and 116b, respectively, are formed. A ground conductor layer 118 and two through holes 119 are formed on the top surface of the dielectric layer 111f. The through hole 119 is not in contact with the ground conductor layer 118. On the upper surface of the dielectric layer 111g, two capacitor conductor layers 120a and 120b and two through holes 121 connected to the capacitor conductor layers 120a and 120b, respectively, are formed. A ground conductor layer 122 is formed on the upper surface of the dielectric layer 111h.
[0090]
The widths of the capacitor conductor layers 116 a, 116 b, 120 a, 120 b are larger than the width of the conductor layer 113. Capacitor conductor layers 116 a and 120 a are connected to the vicinity of one end of conductor layer 113 through through holes 115, 117, 119 and 121. The capacitor conductor layers 116 b and 120 b are connected to the vicinity of the other end of the conductor layer 113 through the through holes 115, 117, 119, and 121. Conductor layer 113 and capacitor conductor layers 116a, 116b, 120a, and 120b constitute resonator 101 shown in FIG. The capacitor conductor layers 116a and 120a correspond to the portion 101a in FIG. The capacitor conductor layers 116b and 120b correspond to the portion 101b in FIG.
[0091]
[Second Example of Resonator Shape]
FIG. 33 is an explanatory diagram showing a resonator 131 of the second example and a rectangular resonator 132 for comparison with the resonator 131. The resonators 131 and 132 are both half-wave resonators that are short-circuited at both ends. The resonance frequencies of the resonators 131 and 132 are equal. In the resonator 131, the width of the portion 131c near the center in the longitudinal direction is larger than the width of the two portions 131a and 131b near the short-circuit end. The widths of the portions 131 a and 131 b are equal to the width of the resonator 132. In the resonator 131, the capacitance near the center in the longitudinal direction is larger than that in the resonator 132. As a result, the physical length of the resonator 131 is smaller than the physical length of the resonator 132.
[0092]
FIG. 34 is an exploded perspective view showing an example of the configuration of the multilayer substrate 30 that realizes the resonator 131 shown in FIG. 33. FIG. 34 shows only a portion of the multilayer substrate 30 in the vicinity of the resonator 131. The multilayer substrate 30 shown in FIG. 34 has eight dielectric layers 141a to 141h stacked in order from the bottom. A ground conductor layer 142 is formed on the upper surface of the dielectric layer 141b. A conductor layer 143 that is long in one direction is formed on the upper surface of the dielectric layer 141c. A capacitor conductor layer 144 and a through hole 145 connected to the capacitor conductor layer 144 are formed on the upper surface of the dielectric layer 141d. A ground conductor layer 146 and a through hole 147 are formed on the upper surface of the dielectric layer 141e. The through hole 147 is not in contact with the ground conductor layer 146. A capacitor conductor layer 148 and a through hole 149 connected to the capacitor conductor layer 148 are formed on the upper surface of the dielectric layer 141f. A ground conductor layer 150 is formed on the upper surface of the dielectric layer 141g.
[0093]
The widths of the capacitor conductor layers 144 and 148 are larger than the width of the conductor layer 143. The capacitor conductor layers 144 and 148 are connected to the central portion of the conductor layer 143 in the longitudinal direction via through holes 145, 147 and 149. The conductor layer 143 and the capacitor conductor layers 144 and 148 constitute the resonator 131 shown in FIG.
[0094]
[Third example of resonator shape]
FIG. 35 is an explanatory diagram showing a resonator 151 of the third example and a rectangular resonator 152 for comparison with the resonator 151. Each of the resonators 151 and 152 is a quarter wavelength resonator in which one end is short-circuited and the other end is opened. The resonance frequencies of the resonators 151 and 152 are equal. In the resonator 151, the width of the portion 151a on the open end side is larger than the width of the portion 151b on the short-circuit end side. The width of the portion 151 b is equal to the width of the resonator 152. In the resonator 151, the capacitance in the open end portion 151 a is larger than that in the resonator 152. As a result, the physical length of the resonator 151 is smaller than the physical length of the resonator 152.
[0095]
FIG. 36 is an exploded perspective view illustrating an example of the configuration of the multilayer substrate 30 that realizes the resonator 151 illustrated in FIG. 35. FIG. 36 shows only a portion of the multilayer substrate 30 in the vicinity of the resonator 151. The multilayer substrate 30 shown in FIG. 36 has eight dielectric layers 161a to 161h stacked in order from the bottom. A ground conductor layer 162 is formed on the top surface of the dielectric layer 161b. A conductor layer 163 that is long in one direction is formed on the top surface of the dielectric layer 161c. A capacitor conductor layer 164 and a through hole 165 connected to the capacitor conductor layer 164 are formed on the upper surface of the dielectric layer 161d. A ground conductor layer 166 and a through hole 167 are formed on the upper surface of the dielectric layer 161e. The through hole 167 is not in contact with the ground conductor layer 166. A capacitor conductor layer 168 and a through hole 169 connected to the capacitor conductor layer 168 are formed on the upper surface of the dielectric layer 161f. A ground conductor layer 170 is formed on the top surface of the dielectric layer 161g.
[0096]
The widths of the capacitor conductor layers 164 and 168 are larger than the width of the conductor layer 163. The capacitor conductor layers 164 and 168 are connected to the vicinity of the open end of the conductor layer 163 through the through holes 165, 167 and 169. The conductor layer 163 and the capacitor conductor layers 164 and 168 constitute the resonator 151 shown in FIG.
[0097]
Here, according to the resonators of the first to third examples, the reason why the physical length can be reduced as compared with the rectangular resonator will be described. In each of the resonators of the first to third examples, the width of the vicinity of the portion where the electric field is maximum in the resonator is made larger than the width of the other portions. FIG. 37 shows an equivalent circuit of the resonator having such a shape. The circuit shown in FIG. 37 includes an inductor 171, a capacitor 172, and a capacitor 173 connected in parallel. One end of each of the inductor 171, the capacitor 172, and the capacitor 173 is grounded. The inductor 171 and the capacitor 172 correspond to an inductance component and a capacitance component in a rectangular resonator. The capacitor 173 corresponds to the capacitance component generated by increasing the width of a part of the rectangular resonator.
[0098]
Here, the inductance of the inductor 171 is L ₀ And the capacitance of the capacitor 172 is C ₀ And the capacitance of the capacitor 173 is C _add And Also, the resonance frequency of the circuit obtained by removing the capacitor 173 from the circuit shown in FIG. ₀ And the resonance frequency of the circuit shown in FIG. ₁ And Resonance frequency f ₀ , F ₁ Are represented by the following equations, respectively.
[0099]
f ₀ = 1 / {2π√ (L ₀ C ₀ )}
[0100]
f ₁ = 1 / [2π√ {L ₀ (C ₀ + C _add ]}]
[0101]
As can be seen from the above two equations, the width of a part of the rectangular resonator is increased to increase the capacitance C _add In the resonator that generates the resonance frequency, the resonance frequency is lower than that of the rectangular resonator. Therefore, if the resonance frequency is not changed, the physical length of the resonator can be reduced by increasing the width of a part of the rectangular resonator.
[0102]
[Fourth Example of Resonator Shape]
The resonator of the fourth example has a shape in which the inductance component in the vicinity of the portion where the electric field is zero in the resonator is larger than that of the rectangular resonator. Specifically, in the resonator of the fourth example, a spiral-shaped inductor is formed in the vicinity of the portion where the electric field is zero in the resonator. According to the resonator having such a shape, the physical length of the area occupied by the resonator can be made smaller than the physical length of the rectangular resonator.
[0103]
FIG. 38 is an exploded perspective view showing an example of the configuration of the multilayer substrate 30 that realizes the resonator of the fourth example. FIG. 38 shows only a portion of the multilayer substrate 30 in the vicinity of the resonator of the fourth example. The multilayer substrate 30 shown in FIG. 38 has eight dielectric layers 181a to 181h stacked in order from the bottom. A ground conductor layer 182 is formed on the upper surface of the dielectric layer 181b. An inductor conductor layer 183 having an approximately 3/4 turn shape is formed on the upper surface of the dielectric layer 181c. On the top surface of the dielectric layer 181d, an inductor conductor layer 184 having a shape of about 3/4 turns and a through hole 185 connected to one end of the inductor conductor layer 184 are formed. A ground conductor layer 186 and a through hole 187 are formed on the upper surface of the dielectric layer 181e. The through hole 187 is not in contact with the ground conductor layer 186. A capacitor conductor layer 188 and a through hole 189 connected to the capacitor conductor layer 188 are formed on the upper surface of the dielectric layer 181f. A ground conductor layer 190 is formed on the top surface of the dielectric layer 181g.
[0104]
The width of the capacitor conductor layer 188 is larger than the width of the conductor layers 183 and 184. One end of the conductor layer 183 is connected to the ground conductor layers 182, 186, and 190 via terminal electrodes (not shown). One end portion of the conductor layer 183 is connected to one end portion of the conductor layer 184 through the through hole 185. The other end of the conductor layer 184 is connected to the capacitor conductor layer 188 via through holes 187 and 189. The conductor layers 183, 184, and 188 constitute a resonator.
[0105]
Other configurations, operations, and effects in the present embodiment are the same as those in the first or second embodiment.
[0106]
[Fourth Embodiment]
Next, a multilayer bandpass filter according to a fourth embodiment of the invention will be described with reference to FIGS. As shown in FIG. 39, the multilayer bandpass filter according to the present embodiment is a half-wavelength resonance with at least one open end included in the bandpass filter unit 4 in the first to third embodiments. Both ends of the vessel 191 are connected via a capacitor 192. The half-wave resonator 191 may be a balanced output half-wave resonator 41A, or other half-wave resonator with both ends open.
[0107]
In FIG. 39, the broken line indicated by reference numeral 193 indicates the center position in the longitudinal direction of the half-wave resonator 191 and the center position between the two conductors constituting the capacitor 192. In the circuit shown in FIG. 39, the potential becomes zero at the position indicated by reference numeral 193. The circuit shown in FIG. 39 is equivalent to the circuit shown in FIG. The circuit shown in FIG. 40 includes a quarter wavelength resonator 191a and a capacitor 192a. The short-circuited end of the quarter wavelength resonator 191a is grounded. The open end of the quarter wavelength resonator 191a is connected to one end of the capacitor 192a. The other end of the capacitor 192a is grounded. The capacitance of the capacitor 192a is twice the capacitance of the capacitor 192 shown in FIG.
[0108]
Therefore, according to the configuration shown in FIG. 39, as compared with the case where both ends of the half-wave resonator 191 are grounded via separate capacitors, the physical properties of the half-wave resonator 191 are reduced using fewer capacitors. The typical length can be reduced.
[0109]
41 is an exploded perspective view showing an example of the configuration of the multilayer substrate 30 that implements the resonator 191 and the capacitor 192 shown in FIG. FIG. 41 shows only a portion of the multilayer substrate 30 in the vicinity of the resonator 191 and the capacitor 192. The multilayer substrate 30 shown in FIG. 41 has nine dielectric layers 201a to 201i stacked in order from the bottom. A ground conductor layer 202 is formed on the upper surface of the dielectric layer 201b. A conductor layer 203 that is long in one direction is formed on the upper surface of the dielectric layer 201c. A capacitor conductor layer 204 and a through hole 205 connected to the capacitor conductor layer 204 are formed on the upper surface of the dielectric layer 201d. A capacitor conductor layer 206 and a through hole 207 connected to the capacitor conductor layer 206 are formed on the upper surface of the dielectric layer 201e. A capacitor conductor layer 208 and a through hole 209 connected to the capacitor conductor layer 208 are formed on the upper surface of the dielectric layer 201f. A capacitor conductor layer 210 and a through hole 211 connected to the capacitor conductor layer 210 are formed on the upper surface of the dielectric layer 201g. A ground conductor layer 212 is formed on the upper surface of the dielectric layer 201h.
[0110]
The widths of the capacitor conductor layers 204, 206, 208 and 210 are larger than the width of the conductor layer 203. The capacitor conductor layers 204 and 208 are connected to the vicinity of one end portion of the conductor layer 203 through the through holes 205 and 209. The capacitor conductor layers 206 and 210 are connected to the vicinity of the other end of the conductor layer 203 through the through holes 207 and 211. The conductor layer 203 constitutes the resonator 191 in FIG. 39, and the capacitor conductor layers 204, 206, 208, 210 constitute the capacitor 192 in FIG.
[0111]
Other configurations, operations, and effects in the present embodiment are the same as those in the first to third embodiments.
[0112]
In addition, this invention is not limited to said each embodiment, A various change is possible. For example, as the resonator 40 constituting the band-pass filter unit 4, various combinations other than those described in the embodiment are possible.
[0113]
【The invention's effect】
As explained above, claims 1 to 4 In the multilayer bandpass filter according to any one of the above, the bandpass filter unit having a plurality of resonators includes a balanced output half-wave resonator composed of a half-wave resonator open at both ends. In addition, the balanced output terminal is directly connected to the half-wave resonator for balanced output. The multilayer bandpass filter according to the present invention includes a multilayer substrate for integrating a plurality of resonators. From the above, according to the present invention, it is possible to realize a multilayer bandpass filter that can output a balanced signal, is small, and can be easily adjusted.
[0114]
Claims 5 In the described multilayer bandpass filter, the bandpass filter unit having a plurality of resonators includes a balanced output ½ wavelength resonator composed of a ½ wavelength resonator with both ends open, It consists of a 4-wavelength resonator, and a pair of 1 / 4-wavelength resonators is placed in one stage between the balanced-wavelength 1 / 2-wavelength resonator and the balanced output terminal Multiple steps Each of the balanced output terminals is directly connected to each of the pair of balanced output quarter wavelength resonators in the final stage. The multilayer bandpass filter according to the present invention includes a multilayer substrate for integrating a plurality of resonators. From the above, according to the present invention, it is possible to realize a multilayer bandpass filter that can output a balanced signal, is small, and can be easily adjusted.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a basic configuration of a multilayer bandpass filter according to a first embodiment of the invention.
FIG. 2 is an explanatory diagram showing a half-wave resonator with both ends open.
FIG. 3 is an explanatory diagram showing a half-wavelength resonator with both ends short-circuited.
FIG. 4 is an explanatory diagram showing a quarter wavelength resonator.
FIG. 5 is an explanatory diagram for explaining the operation of the multilayer bandpass filter according to the first embodiment of the invention.
FIG. 6 is an explanatory diagram for explaining a method of connecting an unbalanced input terminal to an input resonator via a capacitor.
FIG. 7 is an explanatory diagram for explaining a method of directly connecting an unbalanced input terminal to an input resonator without using a capacitor.
FIG. 8 is a circuit diagram of the multilayer bandpass filter of the first configuration example according to the first embodiment of the invention.
9 is an exploded perspective view showing an example of the configuration of a multilayer substrate that realizes the multilayer bandpass filter shown in FIG. 8. FIG.
10 is a perspective view showing an example of the appearance of the multilayer substrate shown in FIG. 9. FIG.
FIG. 11 is a circuit diagram of a multilayer bandpass filter of a second configuration example according to the first embodiment of the present invention.
12 is an exploded perspective view showing an example of the configuration of a multilayer substrate that realizes the multilayer bandpass filter shown in FIG. 11. FIG.
FIG. 13 is a circuit diagram of a multilayer bandpass filter of a third configuration example according to the first embodiment of the invention.
14 is an exploded perspective view showing an example of the configuration of a multilayer substrate that realizes the multilayer bandpass filter shown in FIG. 13. FIG.
FIG. 15 is a circuit diagram of a multilayer bandpass filter of a fourth configuration example according to the first embodiment of the invention.
16 is an exploded perspective view showing an example of the configuration of a multilayer substrate that realizes the multilayer bandpass filter shown in FIG. 15. FIG.
17 is a characteristic diagram showing attenuation / insertion loss characteristics of the multilayer bandpass filter shown in FIG. 8. FIG.
18 is a characteristic diagram showing reflection loss characteristics of the multilayer bandpass filter shown in FIG.
19 is a characteristic diagram illustrating frequency characteristics of an amplitude difference between output signals at balanced output terminals of the multilayer bandpass filter illustrated in FIG. 8;
20 is a characteristic diagram showing frequency characteristics of the phase difference of the output signal at the balanced output end of the multilayer bandpass filter shown in FIG.
FIG. 21 is an explanatory diagram showing a basic configuration of a multilayer bandpass filter according to a second embodiment of the invention.
FIG. 22 is an explanatory diagram for explaining interdigital coupling as a resonator coupling method;
FIG. 23 is an explanatory diagram for explaining comb line coupling as a resonator coupling method;
FIG. 24 is an explanatory diagram for explaining a coupling method between a balanced output quarter-wave resonator and a balanced output half-wave resonator;
FIG. 25 is an explanatory diagram for explaining a coupling method between a balanced output quarter-wave resonator and a balanced output half-wave resonator;
FIG. 26 is an explanatory diagram for explaining a coupling method between a balanced output quarter-wave resonator and a balanced output half-wave resonator;
FIG. 27 is an explanatory diagram for explaining a coupling method between a balanced output quarter-wave resonator and a balanced output half-wave resonator;
FIG. 28 is an explanatory diagram for explaining a coupling method between a balanced output quarter-wave resonator and a balanced output half-wave resonator;
FIG. 29 is an explanatory diagram for explaining a coupling method of the balanced output quarter-wave resonators of two adjacent stages.
FIG. 30 is an explanatory diagram for explaining a coupling method of balanced output quarter-wave resonators in two adjacent stages;
FIG. 31 is an explanatory diagram showing a first example of the shape of a resonator according to the third embodiment of the invention.
32 is an exploded perspective view showing an example of the configuration of a multilayer substrate that realizes the resonator shown in FIG. 31. FIG.
FIG. 33 is an explanatory diagram showing a second example of the shape of the resonator according to the third embodiment of the invention.
34 is an exploded perspective view showing an example of the configuration of a multilayer substrate that realizes the resonator shown in FIG. 33. FIG.
FIG. 35 is an explanatory diagram showing a third example of the shape of the resonator according to the third embodiment of the invention.
36 is an exploded perspective view showing an example of the configuration of a multilayer substrate that realizes the resonator shown in FIG. 35. FIG.
FIG. 37 is a circuit diagram showing an equivalent circuit of the resonators of the first to third examples.
FIG. 38 is an exploded perspective view showing an example of the configuration of a multilayer substrate that realizes the resonator of the fourth example according to the third embodiment of the invention.
FIG. 39 is a circuit diagram showing a circuit composed of a half-wave resonator with open ends and a capacitor according to the fourth embodiment of the present invention.
40 is a circuit diagram showing a circuit equivalent to the circuit shown in FIG. 39. FIG.
41 is an exploded perspective view showing an example of a configuration of a multilayer board that realizes a circuit including the resonator and the capacitor shown in FIG. 39. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Stack type bandpass filter, 2 ... Unbalanced input terminal, 3A, 3B ... Balanced output terminal, 4 ... Bandpass filter part, 40 ... Resonator, 41A ... 1/2 wavelength resonator for balanced output.

Claims (3)

An unbalanced input terminal for inputting an unbalanced signal;
Two balanced output terminals for outputting balanced signals;
A plurality of resonators each consisting of a TEM line, and a band-pass filter unit provided between the unbalanced input end and the balanced output end;
A multilayer substrate for integrating the plurality of resonators,
The band-pass filter unit includes, as the resonator, a half-wave resonator for balanced output composed of a half-wave resonator open at both ends,
The balanced output terminal is directly connected to the balanced output half-wave resonator,
The half-wave resonator for balanced output is composed of one conductor layer,
Furthermore, a DC voltage application terminal used for applying a DC voltage to the half-wave resonator for balanced output is provided,
The DC voltage application terminal is connected to one location near the center in the longitudinal direction of the balanced output half-wave resonator by one terminal conductor layer ,
Furthermore, it comprises two capacitor conductor layers that are connected to both ends of the half-wave resonator for balanced output via through holes, respectively, and form a capacitor between the ground and the ground.
The multilayer bandpass filter, wherein the two capacitor conductor layers are arranged on the same plane . One balanced output terminal is directly connected to one half of the half-wave resonator for balanced output in the longitudinal direction, and the other balanced output terminal is connected to the half-wave resonator for balanced output. The multilayer bandpass filter according to claim 1 , wherein the multilayer bandpass filter is directly connected to the other half portion in the longitudinal direction. An unbalanced input terminal for inputting an unbalanced signal;
Two balanced output terminals for outputting balanced signals;
A plurality of resonators each consisting of a TEM line, and a band-pass filter unit provided between the unbalanced input end and the balanced output end;
A multilayer substrate for integrating the plurality of resonators,
The bandpass filter section includes a balanced output half-wave resonator made up of a half-wave resonator open at both ends and a quarter-wave resonator as the resonator. Between the two-wavelength resonator and the balanced output end, a pair of quarter-wave resonators as a single stage, including a balanced output quarter-wavelength resonator provided in multiple stages,
Each balanced output terminal is directly connected to each of the pair of balanced output 1/4 wavelength resonators in the final stage,
One of the first-stage pair of balanced output quarter-wave resonators closest to the balanced output half-wave resonator is one in the longitudinal direction of the balanced output half-wave resonator. The other half of the pair of balanced output quarter-wave resonators in the first stage is coupled to the other half of the balanced output half-wave resonator in the longitudinal direction. A laminated band-pass filter characterized by being made.

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