JP2003283203A - Dielectric filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small dielectric filter which can stabilize filter characteristics and has high productivity. <P>SOLUTION: A dielectric substrate 6 is disposed in a box-like casing 1, and dielectric films 7, 8 are formed on both surfaces of the plate 6. Also, on the substrate 6, a plurality of both end opening type resonators 9 consisting of slots 9A, 9B which face each other between a front surface 6A and a rear surface 6B are formed, and these resonators 9 are arranged in a direction extending in parallel to allow electric field vectors face each other. In this way, since the adjacent resonators 9 are coupled via an electric field, this filter can decrease a coupling factor, compared with the conventional one employing magnetic field coupling. Thus, the distance between the resonators 9 can be reduced. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric filter suitable for use in high frequency signals such as microwaves and millimeter waves.

[0002]

2. Description of the Related Art Generally, as a dielectric filter, a conductive film is formed on each of a front surface and a back surface of a dielectric substrate, and
There is known a dielectric substrate in which a slot-shaped opening in which a conductor film is cut out is formed so as to face the front surface and the back surface (for example, Japanese Patent Laid-Open No. 11-234008).

In such a conventional technique, by extending both ends or one end of the opening to the end surface of the dielectric substrate,
The open-ended resonator or the open-ended resonator is configured, and a plurality of dielectric substrates are arranged in a casing in such a manner that the open end surfaces of the resonator face each other. Thereby, in the conventional technique, a plurality of resonators are magnetically coupled to form a bandpass filter or the like.

[0004]

By the way, in the above-described dielectric filter according to the prior art, a resonator is formed for each of a plurality of dielectric substrates, and these resonators are mounted in a casing. For this reason, the mounting position of the dielectric substrate is likely to vary, so that there is a problem that the coupling coefficient between the resonators changes and the filter characteristics are not stable.

Further, since a plurality of dielectric substrates are used, a step of assembling these into a casing is required, resulting in poor productivity and high manufacturing cost. Furthermore, in the prior art, since magnetic fields are coupled between the resonators,
Resonators tend to couple more strongly than necessary. For this reason, in order to set the coupling coefficient between the resonators to a predetermined value, it is necessary to increase the distance between the resonators, which tends to increase the size of the entire dielectric filter.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a compact dielectric filter which can stabilize the filter characteristics and has high productivity.

[0007]

In order to solve the above problems, the present invention provides a casing having two conductor surfaces facing each other, and a casing provided between the two conductor surfaces in the casing. A dielectric substrate, conductor films provided on the front surface and the back surface of the dielectric substrate, and slots provided to face the conductor films on the front surface side and the back surface side with the dielectric substrate sandwiched therebetween. It is applied to the provided dielectric filter.

A feature of the structure adopted by the invention of claim 1 is that a plurality of slots are arranged in parallel with respect to the conductor film and arranged in a direction in which electric field vectors face each other.

With this structure, the slot constitutes a resonator and the plurality of resonators are electrically coupled through the inside of the dielectric substrate. As a result, the high-frequency signal input to one slot resonates in the slot and is sequentially coupled to other adjacent slots, so that a band pass filter, a band stop filter, etc. can be configured.

According to the second aspect of the present invention, the plurality of slots constitute a double-ended resonator in which both ends thereof extend to the end surface of the dielectric substrate and are open.

As a result, since there is no conductor film at both ends of the slot where the magnetic field concentrates, the number of places where the surface current of the conductor film concentrates decreases. As a result, the overall conductor loss can be suppressed, and the no-load Q (Qo) of the resonator can be increased as compared with, for example, a double-ended short-circuit type resonator having both ends short-circuited.

According to another aspect of the present invention, one end of each of the plurality of slots extends to the end surface of the dielectric substrate and is open, and the other end is short-circuited by being separated from the end surface of the dielectric substrate by the conductor film. It constitutes an open resonator.

As a result, since the conductor film is not provided at one end of the slot in the portion where the magnetic field is concentrated, the number of locations where the surface current of the conductor film is concentrated is reduced. As a result, the overall conductor loss can be suppressed, and the no-load Q (Qo) of the resonator can be increased as compared with, for example, a double-ended short-circuit type resonator having both ends short-circuited.

According to a fourth aspect of the present invention, at least one slot of the plurality of slots has one end extending to the end surface of the dielectric substrate and opened, and the other end of the slot formed by the conductor film on the end surface of the dielectric substrate. To form a short-circuited one-end open resonator, the one-end open-type resonator is provided on the other end side of the one-end open-type resonator with the conductor film separated, and one end side is short-circuited by the conductor film and the other end side is the dielectric body. A trap resonator that extends to the end face of the substrate and is open is provided.

Thus, the open-ended resonator can be coupled to another resonator composed of a slot to form, for example, a band pass filter or a band stop filter. Also,
By setting the resonance frequency of the trap resonator near the cutoff frequency of the bandpass filter, the amount of attenuation near the cutoff frequency can be increased, and the rise of attenuation near the cutoff frequency can be made steep. it can.

According to a fifth aspect of the present invention, the casing has a partition wall for blocking magnetic field coupling between the plurality of slots.

As a result, the adjacent slots are electric-field-coupled through the dielectric substrate, so that the distance between the resonators can be narrowed as compared with the case where magnetic field coupling is used.

According to a sixth aspect of the present invention, the casing is provided with a space portion that allows magnetic field coupling between the plurality of slots.

As a result, the adjacent slots are electrically coupled through the dielectric substrate and magnetically coupled through the space. At this time, by setting the interval dimension between the slots to a value that cancels the electric field coupling and the magnetic field coupling, the coupling coefficient between the slots can be set to almost zero, so that the isolation between the slots can be improved. it can.

According to a seventh aspect of the invention, the casing has a back surface side printed circuit board having a back surface having a conductor surface which is a back surface side of the two conductor surfaces, and a front surface having a front surface side of the two conductor surfaces. And a front side printed circuit board provided with a conductor surface, the dielectric substrate is sandwiched between the back side printed circuit board and the front side printed circuit board, and the conductor films on the front side and the back side are the front side and the back side. The structure is such that each side is connected to the conductor surface.

As a result, the dielectric filter can be constructed by sandwiching the dielectric substrate between the two printed circuit boards to be the casing, and compared with the case where the casing is made of a metal casing or the like. Since complicated processing is unnecessary, productivity can be improved.

According to an eighth aspect of the present invention, the casing is provided with an input portion located near the dielectric substrate and connectable to one slot, and an output portion connectable to another slot different from the slot. , As a bandpass filter.

Thus, the high frequency signal can be input to one slot through the input section, and the high frequency signal can be sequentially coupled from the one slot to the adjacent slots. Then, since the other slots can output a high frequency signal toward the output section, a band pass filter including a plurality of slots can be formed between the input section and the output section.

According to a ninth aspect of the present invention, the casing is provided with a transmission line located near the dielectric substrate and capable of being coupled to the plurality of slots, and is configured as a band elimination filter.

As a result, since the transmission line is coupled to the plurality of slots, the phase of the transmission line between the slots is 90 °.
By setting to, it is possible to prevent a high-frequency signal in a band centered on the resonance frequency of the slot from propagating in the transmission line, and thus a band stop filter can be configured.

According to a tenth aspect of the present invention, the casing is provided with an input portion, an output portion, and an input / output portion which are located in the vicinity of the dielectric substrate and can be respectively coupled to different slots.
It is configured as a duplexer or a multiplexer.

Thus, a bandpass filter can be formed between the input section and the input / output section, and a bandpass filter can be formed between the input / output section and the output section. Therefore, the bandpass filter can be integrally attached to the duplexer or multiplexer having the input section, the output section and the input / output section.

[0028]

DETAILED DESCRIPTION OF THE INVENTION A dielectric filter according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

First, FIGS. 1 to 3 show a first embodiment, in which 1 is a box-shaped casing made of a conductive metal material, and the casing 1 is cut into, for example, a block-shaped metal body. The bottom body 2 is formed by processing and has an opening on the front surface side, and the lid body 3 is opened on the back surface side and the front surface side of the bottom body 2 is attached. The bottom plate 2A of the bottom body 2 and the lid plate 3A of the lid body 3 form two conductor surfaces facing each other.

Further, the casing 1 is formed with a peripheral wall 1A which is located between the bottom plate 2A and the cover plate 3A and which has a rectangular frame shape and surrounds the outer peripheral side. And casing 1
By being surrounded by the bottom plate 2A, the lid plate 3A, and the peripheral wall 1A, an accommodation space 4 for accommodating a dielectric substrate 6, which will be described later, is defined and adjacent to each other formed in the dielectric substrate 6 inside. A blocking partition wall 5 is formed between the two resonators 9 to block the magnetic field coupling therebetween, and the housing space 4 is partitioned by the blocking partition wall 5 into three chambers corresponding to the resonators 9 described later. There is.

The casing 1 is made of a metal material as a whole. However, for example, a resin material is used to form a resin casing having substantially the same shape as that of the casing 1, and a metal is formed on the entire outer peripheral surface of the resin casing. It may be configured to perform plating.

Reference numeral 6 denotes a dielectric substrate provided in the casing 1 between the bottom body 2 and the lid body 3. The dielectric substrate 6 is provided on the left,
It is formed in a strip shape extending rightward and is arranged at a distance from the bottom plate 2A and the lid plate 3A, and is fixed to the peripheral wall 1A of the casing 1 and the blocking partition wall 5. Further, the dielectric substrate 6 is arranged in the housing space 4 of the casing 1, and a gap is formed between the casing 1 and the front and rear ends thereof. The dielectric substrate 6 is made of a resin material, a ceramic material, or a composite material obtained by mixing and sintering these materials, and is formed in a substantially rectangular flat plate shape.

Reference numerals 7 and 8 denote the front surface 6A and the back surface 6 of the dielectric substrate 6.
Conductor films formed on B respectively, and the conductor films 7 and 8 are
For example, it is formed by patterning a conductive metal thin film of gold, copper, silver or the like on both surfaces together with high precision using a photolithography technique or the like. Then, the conductor film 7,
8 are provided separately by four slots 9A and 9B, respectively. Further, the conductor films 7 and 8 are formed on the peripheral wall 1.
A, is connected to the casing 1 through the blocking partition wall 5, and is held at the same potential as the casing 1 so as not to serve as a floating electrode.

Reference numeral 9 denotes, for example, three resonators provided on the dielectric substrate 6, and the resonator 9 is composed of a pair of slots 9A and 9B provided on the conductor films 7 and 8, respectively. The slots 9A and 9B are provided at positions facing each other with the dielectric substrate 6 interposed therebetween, and the slots 9A and 9B traverse the front and rear directions with respect to the dielectric substrate 6 extending in the left and right directions, and both ends thereof are made of a dielectric material. The groove 6 extends to the end surface of the substrate 6. As a result, both ends of the slots 9A and 9B are electrically opened to form the open-ended resonator 9.

The length dimension L0 of the resonator 9 is, for example, a value of about nλ / 2 (where, λ is the wavelength of the high frequency signal in the dielectric substrate 6 corresponding to the desired resonance frequency).
n: an integer of 1 or more), that is, an integral multiple of a half wavelength.

The three resonators 9 are spaced apart in the left and right directions of the dielectric substrate 6 and extend parallel to each other in the front and rear directions. As a result, the three resonators 9 are arranged so that the electric field vectors E generated in the respective resonators 9 face each other.

On the other hand, from both the front and rear ends of the resonator 9, the magnetic field vector H is directed toward the accommodation space 4 forming the cutoff space.
Is spreading. Therefore, the gap size S between the front and rear ends of the resonator 9 and the casing 1 is set to a value such that the resonance frequency of the resonator 9 is not greatly affected by the casing 1. There is.

Reference numeral 10 denotes an input portion located near the dielectric substrate 6 and capable of being coupled to the resonator 9 on the first stage side.
For example, a microstrip line, a coplanar line (CPW), a CB-CPW (Co
nductor-Backed Coplanar Waveguide) etc. transmission line 1
It is configured by forming 0B. And
The transmission line 10B forms a suspended line in which a ground electrode is not provided on the back surface of the printed circuit board 10A, extends along the open end of the resonator 9 to the left and right of the dielectric substrate 6, and is magnetically coupled to the resonator 9. .

Reference numeral 11 denotes an output portion located near the dielectric substrate 6 and capable of being coupled to the resonator 9 on the final stage side.
It is configured by forming a transmission line 11B on a printed circuit board 11A, similar to the input unit 10. The transmission line 11B extends to the left and right of the dielectric substrate 6 along the open end of the resonator 9 and is magnetically coupled to the resonator 9.

The dielectric filter according to this embodiment has the above-mentioned structure, and its operation will be described below.

First, when a high frequency signal is input to the input section 10, the transmission line 10B and the first-stage resonator 9 are magnetically coupled,
A high frequency signal is excited in the resonator 9. At this time, the resonator 9 strongly excites the high frequency signal having the resonance frequency fo, and also sequentially couples the adjacent resonators 9 by electric field. As a result, a high frequency signal having the resonance frequency fo is excited in the final stage resonator 9, and the final stage resonator 9 and the transmission line 11B of the output unit 11 are magnetically coupled. As a result, the output unit 1
1 outputs a high frequency signal in a band centered on the resonance frequency fo and can block a high frequency signal in another band, so that the dielectric filter operates as a band pass filter.

Next, the operation of the resonator 9 alone will be described with reference to FIGS. 4 and 5.

Since both ends of the resonator 9 are open, the electric field E becomes maximum near the open end.
On the other hand, the magnetic field H spreads in the accommodation space 4 which is a TE blocking area. Since the peripheral wall 1A of the casing 1 is arranged at a position separated from the both ends of the resonator 9 by the gap dimension S, the resonator 9 resonates at a resonance frequency whose length dimension L0 is a half wavelength. The resonance frequency slightly varies depending on the gap size S. Therefore, the resonator 9 has a resonance frequency determined by the length dimension L0 and the gap dimension S, and operates as a one-wavelength resonator that resonates between the two peripheral walls 1A.

Since both ends of the resonator 9 are open, the conductor films 7 and 8 do not exist at both ends of the resonator 9 where the magnetic field is concentrated, and the surface currents of the conductor films 7 and 8 are not present. There will be fewer places to concentrate. As a result, the conductor loss of the entire dielectric filter can be suppressed, and the unloaded Q of the resonator 9 can be suppressed.
(Qo) improves. Therefore, the unloaded Q of the resonator 9 of which both ends are open is about 1.7 to 2 times higher than the unloaded Q of the both-end short-circuited resonator in which both ends are short-circuited with respect to a high frequency signal of 26 GHz, for example. It becomes a value.

Therefore, the material having a relative permittivity εr of 38 has a dielectric loss tangent (tan δ) about 6 times worse than that of a material having a relative permittivity εr of 24, while the material having a relative permittivity εr of 38 is deteriorated. Even if the both-ends open type resonator 9 is constructed by using it, the no-load Q is about 1.2 times higher than the case where the both-ends short-circuit type resonator is constructed by using a material having a relative permittivity εr of 24. (Get better. Therefore, the resonator 9 having a desired unloaded Q can be made of materials having various relative dielectric constants εr, and the degree of freedom in material selection can be increased.

Next, the coupling action between the plurality of resonators 9 will be described with reference to FIGS. 6 to 11.

Here, a case where three or more resonators 9 are coupled can be described by sequentially combining two resonators 9 coupled to each other. Therefore, an analytical model in which two resonators 9 are coupled as shown in FIGS. 6 and 7 will be examined. In the analysis model,
The components corresponding to the embodiment including the three resonators 9 are given a dash ('), and the input unit 10 and the output unit 11 are omitted.

First, when a high frequency signal is excited in one of the resonators 9, a coupling occurs between the two resonators 9 and the high frequency signal is also excited in the other resonator 9. At this time, the two resonators 9 are even modes in which the electric field vectors E excited in the respective resonators 9 are in the same direction (see FIGS. 6 and 7).
Alternatively, they are combined in the odd mode (see FIGS. 8 and 9) in the opposite direction.

The relative permittivity εr of the dielectric substrate 6'is, for example, 24, and the thickness t of the dielectric substrate 6'is, for example, 0.
6 mm, the length L0 of the resonator 9 is set to 1.86 m, for example.
m, the gap dimension S between both ends of the resonator 9 and the peripheral wall 1A of the casing 1 is, for example, 3 mm, the conductor films 7'and 8'and the bottom surface 2A,
When the three-dimensional electromagnetic field simulation is performed with the gap dimension h with the lid surface 3A set to, for example, 1.5 mm,
The analysis results shown in FIGS. 10 and 11 can be obtained.

Here, FIG. 10 shows the relationship between the spacing dimension g between the two resonators 9 and the coupling coefficient k between the resonators 9. On the other hand, FIG. 11 shows the relationship between the interval dimension g between the two resonators 9, the even mode resonance frequency feven of the resonator 9, the odd mode resonance frequency fodd, and the central resonance frequency fc.

In the present embodiment, since the blocking partition wall 5'for blocking the magnetic field coupling is provided between the two resonators 9, the even mode resonance frequency feven is higher than the odd mode resonance frequency fodd. Always higher At this time, the two resonators 9 are not magnetically coupled but are electrically coupled through the dielectric substrate 6 '.

The coupling coefficient k can be expressed by the following equation 1 by the even mode resonance frequency feven and the odd mode resonance frequency fodd.

[0053]

[Equation 1]

Since the coupling coefficient k decreases exponentially as the spacing dimension g between the two resonators 9 increases as shown in FIG. 10, the coupling coefficient k is appropriately set. k can be set to a desired value.

Thus, in the present embodiment, since the plurality of resonators 9 extend in parallel with each other and are arranged in the direction in which the electric field vectors E face each other, the plurality of resonators 9 are formed on the dielectric substrate 6.
The electric field is coupled through the inside of. Therefore, the high frequency signal excited in the first-stage resonator 9 by the input unit 10 resonates in the resonator 9 and is sequentially coupled to the adjacent other resonators 9, so that the resonance frequency of the resonator 9 is centered. It is possible to excite the high frequency signal in the band
A bandpass filter can be constructed.

In particular, since a plurality of resonators 9 are formed on one dielectric substrate 6, all the resonators 9 can be positioned by mounting the dielectric substrate 6 on the casing 1. Therefore, as compared with the case where a dielectric filter is configured by using a plurality of dielectric substrates as in the related art, it is possible to reduce variations in filter characteristics and stabilize the characteristics, and improve productivity. Therefore, the manufacturing cost can be reduced.

Since both ends of the slots 9A and 9B extend to the end surface of the dielectric substrate 6, the both ends open type resonator 9 can be formed. Therefore, the conductor films 7 and 8 are formed on both ends of the slots 9A and 9B where the magnetic field is concentrated.
Therefore, it is possible to reduce the area where the surface currents of the conductor films 7 and 8 are concentrated, and it is possible to suppress the conductor loss of the resonator 9. Therefore, for example, the no-load Q of the resonator 9 can be increased and the loss of the dielectric filter can be reduced as compared with a resonator with both ends short-circuited.

Since the casing 1 is formed with the blocking partition 5 for blocking the magnetic field coupling between the plurality of resonators 9,
Adjacent resonators 9 are electrically coupled through the dielectric substrate 6. Therefore, the coupling coefficient between the resonators 9 can be made smaller than that in the case of magnetic field coupling between the resonators as in the conventional technique, so that the interval between the resonators 9 can be narrowed and the entire dielectric filter can be obtained. Can be miniaturized.

Further, the casing 1 includes a dielectric substrate 6
The input section 1 located near the and connectable to the first-stage resonator 9
Since 0 and the output part 11 that can be coupled to the final stage resonator 9 are provided, a high frequency signal can be propagated by using the coupling between the adjacent resonators 9 from the input part 10 toward the output part 11. A bandpass filter can be easily formed between the input unit 10 and the output unit 11.

Next, FIGS. 12 and 13 show the second embodiment of the present invention.
The present embodiment is characterized in that the plurality of slots are such that one end of each of the slots extends to the end surface of the dielectric substrate and is open, and the other end is separated from the end surface of the dielectric substrate by the conductor film. The purpose is to construct a short-circuited open-ended resonator. In addition, in this embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

Reference numeral 21 denotes a resonator according to the present embodiment. For example, three resonators 21 are provided on the dielectric substrate 6 in the same manner as the resonator 9 according to the first embodiment, and are provided on the conductor films 7 and 8. It is constituted by a pair of slots 21A and 21B provided respectively. Further, the slots 21A and 21B are
Provided at positions facing each other with the dielectric substrate 6 interposed therebetween,
It extends in the front and rear directions of the dielectric substrate 6.

Here, the slots 21A, 21B have their front end sides extending to the end faces of the dielectric substrate 6, but their rear end sides extend to the middle positions in the front and rear directions of the dielectric substrate 6, and the conductor films 7, 8 are formed. It is separated from the end surface of the dielectric substrate 6 by the short-circuit portion 22 that is integrated with. Therefore, slot 2
1A and 21B are open-ended resonators 21 whose front end is electrically open and whose rear end is short-circuited by a short-circuit portion 22.
Are configured.

The length dimension L1 of the resonator 21 is, for example, about (2n-1) λ / 4, where λ is the wavelength of the high frequency signal in the dielectric substrate 6 corresponding to the desired resonance frequency. It is set to a value (however, n is an integer of 1 or more).

Furthermore, the three resonators 21 are spaced apart in the front and rear directions of the dielectric substrate 6 and extend parallel to each other in the left and right directions, so that the electric field vectors generated in the respective resonators 21 face each other. It is arranged.

In this way, also in the present embodiment, it is possible to obtain the same operational effect as the band pass filter as in the first embodiment. However, in this embodiment, the slot 21
Resonator 2 with one end open by opening only the front ends of A and 21B
1, the conductor loss is more likely to occur on the rear end side of the resonator 21 and the no-load Q tends to be lower than in the case of using the resonator of which both ends are open. However, the slots 21A, 2
The length dimension L1 of 1B is 1 of the wavelength λ corresponding to the resonance frequency.
Since it can be set to a value of about / 4 (λ / 4),
The front and rear dimensions of the dielectric substrate 6 can be reduced, and the dielectric filter can be downsized.

In the first and second embodiments, all the resonators 9 and 21 are open-ended type or open-ended type. However, the present invention is not limited to this, and as in the first modification shown in FIG. 14, for example, open-ended resonators 23 are arranged in the first stage and the final stage, and in the middle stage located between these resonators 23. The open-ended resonator 24 may be arranged so that the open-ended resonator and the open-ended resonator are mixed.

Next, FIGS. 15 and 16 show the third embodiment of the present invention.
The embodiment is characterized by the fact that the slots at the first stage and the final stage constitute a single-ended open resonator, and a trap resonator is provided adjacent to the single-ended open resonator. is there. In addition, in this embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

Reference numeral 31 is a resonator provided on both the left and right sides of the dielectric substrate 6, and the resonator 31 is a pair of slots 31 provided on the conductor films 7 and 8 and facing each other.
A and 31B, and slots 31A and 31B
Extends in the front and rear directions. In addition, the slots 31A,
The front end side of 31B extends to the end surface of the dielectric substrate 6 to be opened, and the rear end side extends to an intermediate position in the front and rear directions of the dielectric substrate 6 and is integrated with the conductor films 7 and 8. The resonator 31 is short-circuited by 32 and forms an open-ended resonator 31.

Reference numeral 33 denotes a middle-stage resonator located between the two resonators 31. Like the resonator 31, the resonator 33 extends in the front and rear directions provided on the conductor films 7 and 8, respectively. It is composed of a pair of slots 31A and 31B facing each other. The front ends of the slots 33A and 33B extend to the end surface of the dielectric substrate 6 to open, and the rear ends of the slots 33A and 33B extend to intermediate positions in the front and rear directions of the dielectric substrate 6 to be integrated with the conductor films 7 and 8. Is short-circuited by the short-circuited portion 34, which constitutes an open-ended resonator 33.

The three resonators 31 and 33 are spaced apart in the left and right directions of the dielectric substrate 6 and extend in parallel with each other, and the electric field vectors generated in the resonators 31 and 33 are arranged in directions opposite to each other. And constitutes a bandpass filter as a whole.

Reference numeral 35 denotes a trap resonator provided adjacent to the first-stage and last-stage resonators 31.
Is formed by a pair of slots 35A and 35B provided in the conductor films 7 and 8 and facing each other. The slots 35A and 35B are the slots 31A and 35B of the resonator 31, respectively.
It has a width dimension substantially the same as 31B and extends in the front and rear directions.

Further, the slots 35A and 35B extend in the direction opposite to the slots 31A and 31B with the short-circuit portion 32 interposed therebetween,
The front end side thereof is short-circuited by the short-circuit portion 32, and the rear end side thereof is extended to the end surface of the dielectric substrate 6 and opened, thereby forming a trap resonator 35 of an open-ended type. And
The length dimension L2 of the trap resonator 35 is set so that its resonance frequency is a value near the cutoff frequency of the bandpass filter including the resonators 31 and 33.

Thus, in this embodiment, it is possible to obtain the same effect as that of the first embodiment. However, in the present embodiment, since the trap resonator 35 is provided in the vicinity of the one-end open type resonator 31, the amount of attenuation at the resonance frequency of the trap resonator 35 can be increased, and for example, the bandpass filter cutoff can be reduced. It is possible to make the rise of attenuation near the off frequency steep. This makes it possible to increase the difference in attenuation between the pass band and the attenuation band near the cutoff frequency of the bandpass filter.

Next, FIG. 17 shows a fourth embodiment of the present invention. The feature of this embodiment is that the casing is located near the dielectric substrate and can be coupled to a plurality of slots. A line is provided and the band stop filter is configured. In addition, in this embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

Reference numeral 41 is a transmission line portion provided in the vicinity of the front end surface of the dielectric substrate 6, and the transmission line portion 41 is formed by forming a transmission line 41B on the surface of the printed board 41A, for example. And the transmission line 41B
Extends in the left and right directions of the dielectric substrate 6 along the open ends of the resonators 9, and the phase θ of the transmission line portion 41 between two adjacent resonators 9 is 90 °. Length dimension,
The material and the like of the printed circuit board 41A are set. The transmission line 41B is magnetically coupled to each resonator 9.

Thus, in this embodiment, the transmission line 41B
Is coupled to the three resonators 9, it is possible to prevent a high-frequency signal in a band centered on the resonance frequency of the resonators 9 from propagating through the transmission line 41B, and thus a band stop filter can be configured. .

Next, FIGS. 18 to 25 show a fifth embodiment of the present invention.
The embodiment is characterized by the fact that the casing is formed with a space that allows magnetic field coupling between the plurality of slots. In this embodiment, the first
The same components as those in the embodiment will be designated by the same reference numerals, and the description thereof will be omitted.

Reference numeral 51 denotes a casing according to this embodiment,
The casing 51 is formed of a conductive metal material in a box shape, and includes a bottom body 52 and a lid body 53 that are substantially the same as the bottom body 2 and the lid body 3 according to the first embodiment. The bottom plate 52A of the bottom body 52 and the lid plate 53A of the lid body 53 form a pair of conductor surfaces facing each other.

Further, the casing 51 is provided with a peripheral wall 51A which is located between the bottom plate 52A and the cover plate 53A and which has a rectangular frame shape and surrounds the outer peripheral side. The casing 51 is surrounded by the bottom plate 52A, the lid plate 53A, and the peripheral wall 51A, so that the dielectric substrate 6
An accommodation space 54 for accommodating the is defined.

The bottom plate 5 is provided inside the casing 51.
A connection partition wall 55 extending from 2A and the cover plate 53A toward the dielectric substrate 6 is provided, and the connection partition wall 55 is connected to the conductor films 7 and 8 located between two adjacent resonators 9.
As a result, the conductor films 7 and 8 are connected to the casing 51 through the connection partition wall 55 and are held at the same potential as the casing 51 so as not to serve as floating electrodes.

On the other hand, a gap is formed between the peripheral wall 51A on both front and rear sides of the connection partition wall 55, and a space portion 56 is defined by the gap, which allows magnetic coupling between the adjacent resonators 9. Has been done.

Reference numeral 57 denotes a transmission line portion located near the front end surface of the dielectric substrate 6 and capable of being coupled to the three resonators 9. The transmission line portion 57 is, for example, a transmission line 57B on the surface of the printed board 57A. Is formed by forming.
The transmission line 57B extends to the left and right of the dielectric substrate 6 along the open ends of the resonators 9 and is adjacent to each other.
The length dimension, the material of the printed circuit board 57A, etc. are set so that the phase θ of the transmission line portion 57 between the individual resonators 9 becomes 90 °. The transmission line 57B is magnetically coupled to each resonator 9.

The dielectric filter according to the present embodiment has the above-described structure, and since the transmission line 57B is coupled to the three resonators 9, the high frequency signal in the band centering on the resonance frequency of the resonator 9 is used. Can be prevented from propagating through the transmission line 57B, and a band elimination filter can be configured.

Here, the coupling action between the plurality of resonators 9 will be described with reference to FIGS.

Here, the case where three or more resonators 9 are coupled can be described by sequentially combining two resonators 9 coupled to each other. Therefore, an analytical model in which two resonators 9 are coupled as shown in FIGS. 20 and 21 will be examined. In the analysis model, components corresponding to those of the embodiment including the three resonators 9 are given a dash ('), and the transmission line unit 5
7 is omitted.

First, when a high frequency signal is excited in one of the resonators 9, coupling occurs between the two resonators 9, and the high frequency signal is also excited in the other resonator 9. At this time, the two resonators 9 have an even mode (see FIGS. 20 and 21) in which the electric fields E excited by the respective resonators 9 are in the same direction (see FIGS. 20 and 21) or an odd mode in which the electric fields E are in the opposite directions (see FIGS. 22 and 22). 23)).

The relative permittivity εr of the dielectric substrate 6'is, for example, 24, and the thickness dimension t of the dielectric substrate 6'is, for example, 0.
6 mm, the length L0 of the resonator 9 is set to 1.86 m, for example.
m, the gap dimension S between both ends of the resonator 9 and the peripheral wall 1A of the casing 1 is, for example, 3 mm, the conductor films 7'and 8'and the bottom surface 2A,
When the three-dimensional electromagnetic field simulation is performed with the gap dimension h with the lid surface 3A set to, for example, 1.5 mm,
The analysis results shown in FIGS. 24 and 25 can be obtained.

Here, FIG. 24 shows the relationship between the space dimension g between the two resonators 9 and the coupling coefficient k between the resonators 9. On the other hand, FIG. 25 shows the relationship between the space dimension g between the two resonators 9, the even mode resonance frequency feven of the resonator 9, the odd mode resonance frequency fodd, and the center resonance frequency fc.

In the present embodiment, since the space 56 'for permitting magnetic field coupling is provided between the two resonators 9, electric field coupling between the resonators 9 in the dielectric substrate 6'is provided. Magnetic field coupling in the space portions 56 located on both ends of the resonator 9 is mixed. As a result, the distance g between the resonators 9 is 0 to
In the range of 0.24 mm, the even mode resonance frequency feven
Is higher than the resonance frequency fodd of the odd mode, and the electric field coupling becomes larger than the magnetic field coupling. On the other hand, in the range where the gap dimension g between the resonators 9 is 0.24 mm or more, the even mode resonance frequency feven is lower than the odd mode resonance frequency fodd, and the magnetic field coupling is higher than the electric field coupling. When the distance g between the resonators 9 is 0.24 mm, the electric field coupling and the magnetic field coupling are equal to each other and cancel each other, so that the coupling coefficient between the resonators 9 becomes zero.

Therefore, in the present embodiment, the value (g) at which the space dimension g between the resonators 9 is canceled by the electric field coupling and the magnetic field coupling.
= 0.24 mm) to enhance isolation between the resonators 9.

In this way, also in this embodiment, it is possible to obtain the same effects as those of the first embodiment. However, in this embodiment, since the casing 51 is provided with the space 56 that allows magnetic field coupling between the resonators 9, the gap dimension g between the resonators 9 is set to a value that cancels the electric field coupling and the magnetic field coupling. By doing so, the coupling coefficient between the resonators 9 can be set to almost zero.

Here, for example, when only the electric field coupling is performed between the resonators 9 as in the first embodiment, the distance g between the resonators 9 must be increased (for example, g = 1 mm or more) to perform the coupling. The coefficient cannot be brought close to zero (see FIG. 10).

On the other hand, in the present embodiment, the electric field coupling and the magnetic field coupling cancel each other to set the coupling coefficient between the resonators 9 to substantially zero, so that the interval dimension g between the resonators 9 is set to a small value ( For example, g = 0.24 mm) can be set, and the entire dielectric filter can be downsized.

Next, FIGS. 26 and 27 show a sixth embodiment of the present invention.
This embodiment is characterized in that the casing is composed of a back side printed circuit board and a front side printed circuit board, and a dielectric substrate is sandwiched between these printed circuit boards. In the present embodiment,
The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

Reference numeral 61 denotes a casing according to this embodiment,
The casing 61 is composed of a back surface side printed circuit board 62 and a front surface side printed circuit board 63 having a substantially rectangular shape,
A conductive surface 62A made of a conductive metal thin film is formed on substantially the entire back surface of the back side printed circuit board 62, and
A conductor surface 63A similar to the conductor surface 62A is formed over the entire surface of the front-side printed circuit board 63.

A peripheral wall electrode 62B is formed on the surface of the back side printed circuit board 62 and extends in a strip shape along the outer periphery of the back side printed circuit board 62. The back side printed circuit board 62 is located at an intermediate position in the left and right directions of the back side printed circuit board 62. A connection electrode 62C that can contact the conductor film 8 between the resonators 9 by traversing 62 in the front and rear directions.
Are formed.

On the other hand, on the back surface of the front surface side printed circuit board 63, a peripheral wall electrode 63B extending in a strip shape is formed along the outer peripheral edge of the front surface side printed circuit board 63, and the back surface side printed circuit board 63 is located at an intermediate position in the left and right directions of the back surface side printed circuit board 63. A connecting electrode 63C that can come into contact with the conductor film 7 between the resonators 9 across 63 in the front and rear directions.
Are formed.

Then, these printed circuit boards 62, 63
, A plurality of through holes 64 are formed at intervals sufficiently shorter than the wavelength of the high frequency signal.

The connection electrodes 62C and 63C are connected to the conductor films 7 and 8 of the dielectric substrate 6. As a result, the conductor films 7 and 8 are connected to the conductor surfaces 62A and 63A of the printed boards 62 and 63 through the through holes 64 and are held at the same potential as the conductor surfaces 62A and 63A.

Reference numeral 65 denotes an input section formed on the back side printed circuit board 62. The input section 65 is located in the vicinity of the dielectric substrate 6 and transmits a coplanar line or the like provided on the front side of the back side printed circuit board 62. It is constituted by the line 65A. The transmission line 65A extends along the open end of the resonator 9 on the first stage side and is magnetically coupled to the resonator 9.

Reference numeral 66 denotes an output section formed on the back side printed circuit board 62. The output section 66 is provided on the front surface of the back side printed circuit board 62 in the vicinity of the dielectric substrate 6 like the input section 65. And the transmission line 66A. Then, the transmission line 66A extends along the open end of the resonator 9 on the first stage side and is magnetically coupled to the resonator 9.

As described above, also in this embodiment, it is possible to obtain the same operational effect as the bandpass filter as in the first embodiment. However, in the present embodiment, since the casing 61 is composed of the two printed boards 62 and 63, the dielectric substrate 6 is sandwiched between the two printed boards 62 and 63 to easily form the dielectric filter. Can be assembled. Therefore, as compared with the case where the casing is made of a metal casing or the like, complicated processing is not required, so that the manufacturing cost can be reduced.

Further, since the input portion 65 and the output portion 66 can be formed on the back side printed circuit board 62, the step of attaching the input portion and the like to the casing is omitted as compared with the case where these are formed separately from the casing. It is possible to improve productivity.

In the sixth embodiment, the back side printed circuit board 62 is provided with the input section 65 and the output section 66 to form a band pass filter. However, the present invention is not limited to this. For example, as in the second modification shown in FIG. 28, the transmission line 67 that can be coupled to the three resonators 9 is formed on the back side printed circuit board 62, and the band rejection is performed. You may comprise a filter.

In this case, a gap is provided between the front and rear ends of the connection electrode 62C 'and the peripheral wall electrode 62B' on the back side printed circuit board 62, and the front side and back direction of the connection electrode on the front side printed circuit board. A configuration may be used in which a gap is provided between both ends and the peripheral wall electrode. As a result, it is possible to configure a band elimination filter that is substantially the same as that of the fifth embodiment.

Next, FIG. 29 shows a seventh embodiment of the present invention. The feature of this embodiment is that the casing is provided with an input which is located near the dielectric substrate and can be coupled to different slots. Section, an output section, and an input / output section are provided and configured as a duplexer. In addition, in this embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

Reference numeral 71 denotes a casing according to this embodiment,
The casing 71 is formed of a conductive metal material into a box shape, and is composed of a bottom body and a lid body (only the bottom body is shown) substantially similar to the bottom body 2 and the lid body 3 according to the first embodiment. The bottom plate of the bottom body and the cover plate of the lid body form two conductor surfaces facing each other.

Further, the casing 71 is formed with a peripheral wall 71A having a quadrangular frame shape surrounding the outer peripheral side thereof. Further, a housing space 72 for housing the two dielectric substrates 6 is defined inside the casing 71, and four blocking partitions 73 for blocking the magnetic field coupling between the resonators 9 are provided. 73 is connected to the conductor films 7 and 8 located between two adjacent resonators 9.

Inside the casing 71, two dielectric substrates 6 are attached by being sandwiched between the bottom body and the lid body,
These dielectric substrates 6 are arranged apart from each other in the left and right directions.

Reference numeral 74 denotes an input portion located near the front side of the left dielectric substrate 6 and capable of being coupled to the resonator 9 on the first stage side. The input portion 74 has a transmission line 74B formed on the surface of the printed circuit board 74A. And the transmission line 74
B extends along the open end of the resonator 9 and is magnetically coupled to the resonator 9.

Reference numeral 75 denotes an output portion located near the front side of the dielectric substrate 6 on the right side and capable of being coupled to the resonator 9 on the final stage side. The output portion 75 is substantially the same as the input portion 74.
And the transmission line 75B extends along the open end of the resonator 9 and is magnetically coupled to the resonator 9.

Reference numeral 76 is an input / output section arranged near the rear side of the two dielectric substrates 6, and the input / output section 76 is formed by forming a transmission line 76B on the surface of the printed board 76A. The transmission line 76B extends along the open end of the resonator 9 on the final stage side with respect to the dielectric substrate 6 on the left side, and opens the resonator 9 on the initial stage side with respect to the dielectric substrate 6 on the right side. It extends along the edge. As a result, the transmission line 76B is magnetically coupled to the resonators 9 of the two dielectric substrates 6 respectively.

In this way, also in this embodiment, it is possible to obtain the same effect as that of the first embodiment. However, in the present embodiment, since the input section 74, the output section 75, and the input / output section 76 that can be respectively coupled to different resonators 9 are provided,
The high frequency signal input from the input unit 74 can be propagated to the input / output unit 76 while maintaining the band pass characteristic, and the high frequency signal input from the input / output unit 76 can be retained while maintaining the band pass characteristic and output unit 75. Can be propagated to. Therefore, it is possible to configure a duplexer including a bandpass filter, and it is possible to reduce the size of the duplexer as compared with a duplexer configured by using two bandpass filters separately and independently.

In the seventh embodiment, a single input section 74 and a single output section 75 are attached to the casing 71 to form a duplexer, but a plurality of input sections, output sections, etc. are provided. The multiplexer may be configured by mounting.

In the first and second embodiments, the bandpass filter is constructed with the casing 1 provided with the blocking partition 5 for blocking the magnetic field coupling between the resonators 9. Casing 1 as in the fifth embodiment
The bandpass filter may be configured with a space portion that allows magnetic field coupling between the resonators 9 to be provided.

Further, in each of the above-mentioned embodiments, the dielectric filter is constructed by using the three resonators 9, 21, 22, 23, 31, 33, but, for example, two resonators are used. May be used to form a dielectric filter, or four or more resonators may be used to form a dielectric filter.

[0117]

As described above in detail, according to the first aspect of the invention, the dielectric substrate has a plurality of slots extending in parallel with each other and arranged in the direction in which the electric field vectors face each other. A plurality of resonators are field-coupled through the inside of the dielectric substrate while forming a resonator. As a result, the high-frequency signal input to one slot resonates in the slot and is sequentially coupled to other adjacent slots, so that a band pass filter, a band stop filter, etc. can be configured. Further, since the plurality of resonators are electrically coupled to each other, the distance between the resonators can be made shorter than that of the magnetic field coupling as in the conventional technique, and the entire dielectric filter can be downsized. Furthermore, since a plurality of resonators are provided on a single dielectric substrate,
Compared with the case of using a plurality of dielectric substrates, the filter characteristics can be stabilized and the productivity can be improved.

According to the second aspect of the present invention, since the both ends open type resonator is constituted by the slots, the conductor film can be omitted from both ends of the slot where the magnetic field is concentrated, and the overall conductor loss can be suppressed to suppress the resonator. No load Q can be increased.

According to the invention of claim 3, since the one-end open type resonator is constituted by the slots, the conductor film at one end of the slot in the portion where the magnetic field is concentrated can be omitted, and the both-end short-circuit type resonator can be obtained. In comparison, the unloaded Q of the resonator can be increased. Further, when the same resonance frequency is set, the length dimension of the slot can be shortened as compared with the open-ended resonator, and the dielectric filter can be downsized.

According to the invention of claim 4, the one-end open type resonator is constituted by the slot, and the trap resonator is provided in the vicinity of the one-end open type resonator. Therefore, the one-end open type resonator is used. A band pass filter and a band stop filter can be configured. Also, by setting the resonance frequency of the trap resonator near the cutoff frequency of a bandpass filter, etc., the amount of attenuation near the cutoff frequency can be increased, and the rise of attenuation near the cutoff frequency can be made steep. You can

According to the fifth aspect of the present invention, since the blocking partition for blocking the magnetic field coupling between the plurality of slots is formed in the casing, the adjacent slots can be field-coupled through the dielectric substrate, and the magnetic field It is possible to reduce the distance between the resonators and to downsize the entire dielectric filter as compared with the case of using the coupling.

According to the sixth aspect of the present invention, the casing is formed with the space portion that allows the magnetic field coupling between the plurality of slots. Therefore, the adjacent slots are electrically coupled through the dielectric substrate and the space portion through the space portion. Magnetic field coupling. At this time, by setting the interval dimension between the slots to a value that cancels the electric field coupling and the magnetic field coupling, the coupling coefficient between the slots can be set to almost zero, so that the isolation between the slots can be improved. it can. Further, since the distance between the slots is set to a value that cancels the electric field coupling and the magnetic field coupling, the distance between the resonators is narrowed as compared with the case where only one of the electric field coupling and the magnetic field coupling is used, and the entire dielectric filter is It can be miniaturized.

According to the invention of claim 7, since the dielectric substrate is sandwiched between the back side printed circuit board and the front side printed circuit board, the dielectric substrate is sandwiched between the two printed circuit boards to be the casing. By sandwiching the substrate, the dielectric filter can be configured, and since complicated processing is not required as compared with the case where the casing is formed of a metal casing or the like, productivity can be improved.

According to the eighth aspect of the present invention, the casing is provided with an input portion located near the dielectric substrate and connectable to one slot, and an output portion connectable to another slot different from the slot. Since it is provided, it is possible to configure a bandpass filter including a plurality of slots between the input section and the output section.

According to the ninth aspect of the present invention, the casing is provided with the transmission line portion which is located near the dielectric substrate and can be coupled to the plurality of slots. Therefore, the phase of the transmission line between the slots is set to 90 °. By setting, it is possible to prevent a high-frequency signal in a band centered on the resonance frequency of the slot from propagating in the transmission line, and to configure a band-stop filter.

According to the tenth aspect of the invention, since the casing is provided with the input section, the output section and the input / output section which are located in the vicinity of the dielectric substrate and can be respectively coupled to the different slots, the band pass filter is provided. A duplexer and a multiplexer can be configured.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a dielectric filter according to a first embodiment.

FIG. 2 is a plan view showing the dielectric filter according to the first embodiment with a lid removed.

FIG. 3 is a cross-sectional view of the dielectric filter as viewed in the direction of arrows III-III in FIG.

FIG. 4 is a plan view showing the resonator in FIG. 2 as a single body.

5 is a cross-sectional view of the resonator as seen from the direction of arrows VV in FIG.

FIG. 6 is an explanatory view seen from the same position as FIG. 2 showing a state where two resonators according to the first embodiment are coupled in an even mode.

7 is a cross-sectional view as seen from the direction of arrows VII-VII in FIG.

FIG. 8 is an explanatory view seen from the same position as FIG. 2 showing a state where two resonators according to the first embodiment are coupled in an odd mode.

9 is a cross-sectional view as seen from the arrow IX-IX direction in FIG.

FIG. 10 is a characteristic diagram showing a relationship between a space dimension between two resonators and an absolute value of a coupling coefficient according to the first embodiment.

FIG. 11 is a characteristic diagram showing a relationship between a space dimension between two resonators and a resonance frequency according to the first embodiment.

FIG. 12 is a plan view showing the dielectric filter according to the second embodiment with a lid removed.

FIG. 13 is a bottom view showing the dielectric substrate in FIG. 12 as a single body.

FIG. 14 is a plan view showing a dielectric filter according to a first modified example with a lid removed.

FIG. 15 is a plan view showing the dielectric filter according to the third embodiment with a lid removed.

16 is a bottom view showing the dielectric substrate in FIG. 15 as a single body.

FIG. 17 is a plan view showing a dielectric filter according to a fourth embodiment with a lid removed.

FIG. 18 is a plan view showing the dielectric filter according to the fifth embodiment with a lid removed.

19 is a cross-sectional view of the dielectric filter as seen from the direction of the arrow XIX-XIX in FIG.

FIG. 20 is an explanatory view seen from the same position as FIG. 18, showing a state in which two resonators according to the fifth embodiment are coupled in an even mode.

21 is a cross-sectional view as seen from the direction of arrows XXI-XXI in FIG.

FIG. 22 is an explanatory view seen from the same position as FIG. 18, showing a state where two resonators according to the fifth embodiment are coupled in an odd mode.

23 is a cross-sectional view as seen from the direction of arrows XXIII-XXIII in FIG. 22.

FIG. 24 is a characteristic diagram showing the relationship between the distance between two resonators and the absolute value of the coupling coefficient according to the fifth embodiment.

FIG. 25 is a characteristic diagram showing a relationship between a space dimension between two resonators and a resonance frequency according to the fifth embodiment.

FIG. 26 is a plan view showing the dielectric filter according to the sixth embodiment with the front side printed circuit board removed.

FIG. 27 shows a dielectric filter as indicated by arrows in FIG. 26 XXVII-XXV.
It is the sectional view seen from the II direction.

FIG. 28 is a plan view showing a dielectric filter according to a second modification with the front side printed circuit board removed.

FIG. 29 is a plan view showing a dielectric filter according to a seventh embodiment with a lid removed.

[Explanation of symbols]

1, 51, 61, 71 Casing 2A, 52A Bottom plate (conductor surface) 3A, 53A Cover plate (conductor surface) 5, 55 Breaking partition wall 6 Dielectric substrate 7, 8 Conductor film 9, 24 Resonator (both ends open type resonator) ) 9A, 9B, 21A, 21B, 31A, 31B, 33
A, 33B Slot 10, 65, 74 Input part 11, 66, 75 Output part 21, 23, 31, 33 Resonator (single end open type resonator) 35 Trap resonator 41B, 57B, 67 Transmission line 56 Space part 62 Rear surface Side printed circuit board 63 Front side printed circuit board 62A, 63A Conductor surface 76 Input / output section

Continued front page    (72) Inventor Kiyoshi Kanagawa             2-10-10 Tenjin, Nagaokakyo, Kyoto Stock             Murata Manufacturing Co., Ltd. (72) Inventor Keiichi Hirose             2-10-10 Tenjin, Nagaokakyo, Kyoto Stock             Murata Manufacturing Co., Ltd. (72) Inventor Kazuhiro Yamaji             2-10-10 Tenjin, Nagaokakyo, Kyoto Stock             Murata Manufacturing Co., Ltd. F term (reference) 5J006 HC03 JA01 JA02 KA03 LA02                       LA03 LA12 LA21 LA25 NA01                       NA08 PA01 PA10

Claims (10)

[Claims] 1. A casing having two conductor surfaces facing each other, a dielectric substrate provided between the two conductor surfaces in the casing, and a front surface and a back surface of the dielectric substrate, respectively. And a slot provided to face the conductor films on the front surface side and the back surface side with the dielectric substrate interposed therebetween.
The dielectric filter, wherein a plurality of the slots extend parallel to the conductor film and are arranged in a direction in which electric field vectors face each other. 2. A dielectric filter according to claim 1, wherein both ends of the plurality of slots extend to the end face of the dielectric substrate and are open to form an open-ended resonator. 3. A single-ended open resonator in which one end of each of the plurality of slots extends to the end surface of the dielectric substrate and is opened, and the other end is short-circuited by being separated from the end surface of the dielectric substrate by the conductor film. The dielectric filter according to claim 1, which comprises: 4. At least one slot of the plurality of slots has one end extending to the end surface of the dielectric substrate and opened, and the other end separated from the end surface of the dielectric substrate by the conductor film. A short-circuited open-ended resonator is configured, and the open-ended resonator is provided on the other end side of the open-ended resonator with the conductor film interposed therebetween. The dielectric filter according to claim 1, wherein the trap resonator is extended and opened. 5. The dielectric filter according to claim 1, 2, 3, or 4, wherein the casing is formed with a blocking partition for blocking magnetic field coupling between the plurality of slots. 6. The dielectric filter according to claim 1, wherein the casing is formed with a space that allows magnetic field coupling between the plurality of slots. 7. The casing has a back surface side printed circuit board having a back surface provided with a conductor surface which is a back surface side of the two conductor surfaces, and a conductor having a front surface which is a front surface side of the two conductor surfaces. A front side printed circuit board provided with a surface, the dielectric substrate is sandwiched between the back side printed circuit board and the front side printed circuit board, and the conductor films on the front side and the back side are the front side and the back side. The dielectric filter according to claim 1, 2, 3, 4, 5 or 6, which is configured to be respectively connected to the conductor surfaces on the side. 8. The bandpass filter is provided with an input unit located near the dielectric substrate and couplable to one slot, and an output unit couplable to another slot different from the slot. Claim 1, which is configured as a filter
The dielectric filter described in 2, 3, 4, 5, 6 or 7. 9. The casing is provided with a transmission line located near the dielectric substrate and capable of being coupled to the plurality of slots, and configured as a band elimination filter. The dielectric filter described in 4, 5, 6 or 7. 10. The casing is provided with an input section, an output section and an input / output section which are located in the vicinity of the dielectric substrate and can be respectively coupled to different slots, and are configured as a duplexer or a multiplexer. The dielectric filter described in 1, 2, 3, 4, 5, 6 or 7.