JPH05251905A - Layered dielectric filter - Google Patents

Abstract

PURPOSE:To make the dielectric filter small and to effectively improve the characteristic of an insertion loss for a pass band by effectively increasing the attenuation of high frequency and low frequency portions of the pass band while minimizing number of stages of resonators being components of the dielectric filter. CONSTITUTION:Resonance electrodes 26, 26 located side by side at both sides in the dielectric filter provided with 4-stages of 1/4 wavelength tri-plate resonators corresponding to four resonance electrodes 26 arranged in a dielectric board 20 are arranged in a comb-line structure and a capacitance is added between their open ends to allow them to be capacitance-coupled. On the other hand, the resonance electrodes 26, 26 located side by side in the middle are arranged in an interdigital structure to allow them to be inductive-coupled.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a laminated dielectric filter useful as a high frequency filter or a duplexer used in a high frequency wireless device represented by a mobile phone or the like.

[0002]

BACKGROUND ART Recently, in various high-frequency wireless devices,
In order to reduce the loss, dielectric filters using various dielectric ceramics are used. As such a dielectric filter, for example, a filter using a coaxial resonator as shown in FIG.
A filter using a triplate resonator as shown in FIG. 1 is well known.

Among them, in the dielectric filter using the coaxial resonator shown in FIG. 9, a plurality of resonators 2 having a structure in which an inner conductor 4 and an outer conductor 6 are provided in a rectangular parallelepiped dielectric block 8 ( (Three are used here), and a desired frequency characteristic is obtained by coupling them by capacitive coupling. Specifically, the dielectric substrate 10 separate from the resonator 2
Is provided and a plurality of coupling electrodes 12 corresponding to the respective resonators 2 are arranged on the dielectric substrate 10, the capacitance between the coupling electrodes 12 causes the coupling between the resonators. The capacity is formed. In the figure, 5 is a solder and 7 is an input / output terminal.

On the other hand, in the dielectric filter using the triplate resonator shown in FIG. 10, a desired frequency characteristic is obtained by coupling a plurality of resonators (resonance electrodes 16) with each other by inductive coupling. Has been obtained. In particular,
A plurality of quarter-wavelength resonance electrodes 16 (three here are formed) arranged in parallel in a rectangular plate-shaped dielectric substrate 14 have open ends (sides not connected to the ground electrode 18). By arranging such that the end portion) and the short-circuit end (the end portion on the side connected to the ground electrode 18) are staggered, they are coupled by an electromagnetic phenomenon based on the arrangement. In the figure, reference numeral 17 is an input / output electrode.

In the dielectric filter using such a triplate resonator, all the resonance electrodes 16 are used.
Is placed so that its open end and short-circuited end are in the same direction,
Moreover, it is also possible to couple a plurality of resonators by capacitive coupling by adding a capacitance between the open ends. On the other hand, also in a dielectric filter using a coaxial resonator, for example, a plurality of internal conductors 4 are provided for one dielectric block 8 so that adjacent internal conductors 4 and 4 are provided.
By arranging the inner conductors 4 closer to each other, forming a through hole for coupling between the inner conductors 4 and 4, or arranging the inner conductors 4 so that the open ends and the shorted ends are staggered. Although inductive coupling may be realized, in practice, there are problems such as press working of the dielectric block 8, a complicated printing process of the conductor, and a problem of hindering miniaturization of the filter. , Not well adopted.

Furthermore, in Japanese Patent Laid-Open No. 3-72706, a resonator is formed by incorporating a capacitor formed through a dielectric in a dielectric substrate and a coil pattern connected in series to the capacitance. It has been clarified that a plurality of resonators thus formed are coupled by mutual inductance between coil patterns to obtain a desired frequency characteristic.

By the way, the good or bad of the frequency characteristics of the dielectric filter is mainly judged from the insertion loss in the pass band and the amount of attenuation at a specific frequency outside the pass band. The attenuation amount is usually set as the minimum guaranteed attenuation amount at a point distant from the pass band by a predetermined frequency. For example, at the center frequency (f ₀ ) ± 32.5 MHz, 4
It is decided to be 0 dB or more.

However, in the conventional dielectric filter as shown in FIGS. 9 and 10, the frequency characteristic appears as shown in FIG. 11 or 12, and the pass band (center frequency: f ₀ ).
There is a problem that the required attenuation amount cannot be obtained on the opposite side even if the required attenuation amount is obtained on one of the high frequency side and the low frequency side. That is, as is generally known, as a characteristic of the coupling circuit, in the capacitive coupling, the attenuation on the low frequency side of the pass band is good, but on the high frequency side, it is poor, and in the inductive coupling, the opposite is true. The characteristic of such a coupling circuit adversely affects the frequency characteristic of the filter. Therefore, in the dielectric filter of FIG. 9 which employs only capacitive coupling as a coupling means between the resonators, the attenuation characteristic becomes worse on the high frequency side of the pass band as shown in FIG. In the dielectric filter of FIG. 10 which employs only inductive coupling as a means, the attenuation characteristic deteriorates on the low frequency side of the pass band as shown in FIG. 12, and an effective attenuation characteristic cannot be obtained.

Therefore, conventionally, when a dielectric filter is manufactured, a sufficient attenuation amount can be obtained with a better attenuation characteristic on the high frequency side or the low frequency side of the pass band at a certain number of resonator stages. However, by increasing the number of resonators further, the overall attenuation amount is increased so that the worse attenuation amount in the high frequency side or low frequency side of the pass band reaches the required attenuation amount. Was there. However, in that case, at the same time, there is a problem that the insertion loss in the pass band increases and the filter becomes large. Then, in order to reduce the insertion loss while maintaining the number of resonators, it is necessary to increase the Q of the resonator to be used, but generally, in order to increase the Q of the resonator, the shape of the resonator must be increased. However, this immediately leads to an increase in the size of the filter, which goes against the recent strict demand for miniaturization of parts.

[0010]

The present invention has been made in view of such circumstances, and the problem to be solved by the present invention is to reduce the attenuation characteristics of a dielectric filter without unnecessarily increasing the number of resonator stages. This is to improve the size of the dielectric filter and to improve the characteristics of the insertion loss in the pass band.

[0011]

In order to solve the above problems, the present invention comprises a resonance electrode arranged in a dielectric substrate and a ground electrode provided on both main surfaces of the dielectric substrate. In a triplate type line, one end of the resonance electrode is opened and the other end is short-circuited to the ground electrode.
A quarter-wavelength triplate resonator is used as a dielectric filter having three or more stages, and the coupling between the resonators is configured by at least one capacitive coupling and at least one inductive coupling. The gist of the present invention is a laminated dielectric filter.

Further, in such a laminated dielectric filter, the capacitive coupling is preferably arranged such that at least a pair of adjacent resonators are arranged in parallel with each other so that their open ends and shorted ends are oriented in the same direction. And is formed by adding capacitance between their open ends, while inductive coupling causes at least one pair of adjacent resonators to be brought together such that their open and shorted ends are in the same direction. It is formed by arranging in parallel and adding a capacitance between the open end of at least one of the resonators and the ground electrode so that the coupled electrical length of the resonators is controlled to a predetermined value. The Rukoto. Alternatively, the inductive coupling can also be advantageously formed by arranging at least one set of adjacent resonators parallel to each other such that their open and shorted ends are staggered.

[0013]

[Operation / Effect] In short, in such a dielectric filter, since the coupling between the resonators includes both capacitive coupling and inductive coupling, the characteristics of both coupling circuits are added,
Both attenuations on both sides of the passband can be effectively controlled. Therefore, it is possible to configure the dielectric filter using the minimum required number of resonators without unnecessarily increasing the number of resonators, and it is possible to advantageously reduce the size of the dielectric filter. Moreover, the insertion loss in the pass band can be effectively reduced by saving the number of resonator stages.

Further, since such a dielectric filter is constructed by using a triplate type resonator, a comb line structure (a plurality of resonators having open ends thereof) having a narrow space between the resonators is formed by a printing process. And the interdigital structure (structures in which multiple resonators are arranged in parallel so that their open ends and shorted ends are staggered) are easy. It is possible to form a capacitive coupling and an inductive coupling very easily.

[0015]

EXAMPLES Hereinafter, in order to more specifically clarify the present invention, typical examples of the laminated dielectric filter according to the present invention will be described in detail with reference to the drawings.

First, FIGS. 1 to 3 show an example of a laminated dielectric filter according to the present invention. Reference numeral 20 denotes a substantially rectangular plate-shaped dielectric substrate made of various dielectric ceramics, on which a ground electrode 22 is formed on substantially the entire surface thereof, and a pair of side surfaces facing each other in the longitudinal direction. Has a pair of input / output terminals 24, 24 in a state of not being electrically connected to the ground electrode 22. On the other hand, inside the dielectric substrate 20, four 1/4 wavelength resonance electrodes 26 are formed in parallel with each other in the pattern shown in FIG. In addition, the pair of input / output electrodes 2 are provided at positions sandwiching the resonance electrodes 26.
8 and 28 are formed, and the input / output electrodes 28 and 28 are formed.
Are connected to the input / output terminals 24, 24. Thus, here, 1/4 is provided corresponding to each resonance electrode 26.
The wavelength triplate resonator is provided in four stages.

By the way, the four resonance electrodes 26 are
As is apparent from FIG. 2, the two on one side are arranged in parallel with each other so that the open end and the short-circuited end are in the same direction, and the two on the opposite side are opposite to each other and the open end and the short-circuited end are in the same direction. Are arranged in parallel with each other. In other words, the resonance electrodes 26 are arranged so that the groups on both sides have a combline structure and the central group has an interdigital structure.

In the combline structure set, the resonance electrodes 26 facing each other at the open end of each resonance electrode 26.
The coupling electrode 30 that extends toward the side is integrally provided. As a result, capacitance is added between the open ends by the electrostatic capacitance between the coupling electrodes 30 and 30, and the resonance electrodes 26 and 26 are coupled by capacitive coupling. On the other hand, in the set of interdigital structure, the two resonance electrodes 26, 26 are coupled by inductive coupling due to an electromagnetic phenomenon based on their arrangement. That is, in this dielectric filter, the four resonance electrodes 26
In between, the capacitive coupling, the inductive coupling, and the capacitive coupling are realized in order from one side, and the equivalent circuit is as shown in FIG. The resonance electrodes 26 located at both ends are further provided with coupling electrodes 32 for adding capacitance between the resonance electrodes 26 and the input / output electrodes 28.

Therefore, in such a dielectric filter, the coupling between the resonators (resonance electrodes 26) includes both capacitive coupling and inductive coupling, so that the characteristics of both coupling circuits are added to pass through. The attenuations on both sides of the band (center frequency: f ₀ ) can be efficiently controlled together, and excellent frequency characteristics as shown in FIG. 5 can be obtained. Then, the minimum guaranteed attenuation amount set at a point distant from the pass band by a predetermined frequency (for example, f ₀ ± 35 MHz) is achieved with the minimum required number of stages, which advantageously realizes downsizing of the filter. Is done. Further, by saving the number of stages of the resonator (resonance electrode 26), the insertion loss in the pass band can be effectively reduced.

Further, in such a dielectric filter, since the triplate resonator is used, both the combline structure and the interdigital structure of the resonance electrode 26 are extremely easily formed by a printing process. Therefore, both capacitive coupling and inductive coupling can be formed extremely easily.

FIGS. 6 and 7 show another embodiment of the laminated dielectric filter according to the present invention. As shown in FIG. 7, this dielectric filter is constructed by laminating a total of seven dielectric substrates 40 each having a predetermined electrode pattern formed thereon. Specifically, ground electrodes 42 are provided on the upper surface of the first dielectric substrate 40 from the top and the lower surface of the seventh dielectric substrate 40, respectively. Further, on the upper surface of each of the second, third, sixth, and seventh dielectric substrates 40 from the top, one quarter-wavelength resonance electrode 46 extending in the longitudinal direction of the substrate is provided. The
A connecting electrode 54 for connecting to the ground electrode 42 is integrally provided at the short-circuit end. Thus, here, four quarter-wavelength triplate resonators are provided corresponding to each resonance electrode 46.

Further, an input / output electrode 48 is provided on each of the second and seventh dielectric substrates 40 from the top so as to be located on the open end side of the resonance electrode 46. In addition, the upper surface of each of the fourth and fifth dielectric substrates from the top is connected to the open end of the resonance electrode 46 on the third and sixth dielectric substrates 40, respectively. An electrode 50 for use is provided. The connection between the coupling electrode 50 and the resonance electrode 46 is realized by the conductor in the through hole 52 formed on the third and fifth dielectric substrates 40 from the top.

Then, the dielectric substrates 40 are laminated and integrated to form an integral dielectric filter as shown in FIG.
The upper and lower ground electrodes 4 are provided on the side surface of the dielectric filter.
An electrode 56 for short-circuiting the second and second electrodes 42 is burnt in, and is electrically disconnected from the ground electrode 42 and the electrode 56, and is connected to the input / output electrodes 48, 48 so as to be predetermined. A pair of input / output terminals 44, 4 at the position
4 are provided.

In this dielectric filter, as is apparent from FIG. 7, the resonance electrodes 46 and 46 at the first and second stages and the resonance electrodes at the third and fourth stages from the top. The electrodes 46, 46 are arranged so that the directions of the open end and the short-circuited end are opposite to each other, so that they are coupled to each other by inductive coupling. On the other hand, the resonance electrodes 46, 46 of the second and third steps from the top are arranged so that the open end and the short-circuited end have the same direction, and the coupling electrode 50 is provided between the open ends. As a result of the addition of a predetermined capacitance, they are coupled to each other by capacitive coupling.

Therefore, even in such a dielectric filter, since both the capacitive coupling and the inductive coupling are included in the coupling between the resonators (resonance electrode 46), the attenuation on both sides of the pass band can be efficiently controlled. Therefore, the number of resonator stages can be minimized, whereby the size of the filter and the insertion loss in the pass band can be advantageously improved. Further, since the triplate resonator is used, the resonance electrode 46 can be easily arranged in various modes in the printing process, and both the capacitive coupling and the inductive coupling can be formed very easily. Can be done.

Further, FIG. 8 shows another embodiment of the laminated dielectric filter according to the present invention. This dielectric filter has substantially the same structure as the dielectric filter shown in FIGS. 1 to 3, and FIG. 8 corresponds to FIG.

That is, reference numeral 60 denotes a dielectric substrate having a substantially rectangular plate shape, a ground electrode 62 is formed on substantially the entire surface thereof, and a pair of side surfaces facing each other in the longitudinal direction are provided with a ground electrode 62. A pair of input / output terminals 64, 64 are formed in a state of not being electrically connected to the ground electrode 62. Then, inside the dielectric substrate 60, five 1 /
The four wavelength resonance electrodes 66 are parallel to each other and all have a combline structure (a structure in which the open end and the short-circuited end have the same direction).
Are arranged and formed so that Further, a pair of input / output electrodes 68, 68 are formed at positions sandwiching the resonance electrodes 66 therebetween.
68 is connected to the input / output terminals 64, 64.
Thus, here, the number of resonance electrodes 66 is 1
Five quarter-wavelength triplate resonators are provided.

In the set of the resonance electrodes 66 and 66 in the first and second stages from the left, the coupling electrode 7 extended toward the opposing resonance electrode 66 at each open end.
0 is provided integrally. As a result, a predetermined capacitance is added between the open ends, and thus the pair of resonance electrodes 66, 66 are coupled by capacitive coupling.

On the other hand, in each of the third and fourth resonance electrodes 66 from the left, the ground electrode 6 is provided at a position facing the open end.
Since the electrodes 74 connected to 2 are provided respectively, a predetermined capacitance is added between the open end of the resonance electrode 66 and the ground electrode 62. As a result, the resonance electrode 66 is actually formed to have a wavelength of 1/4 or less and the coupling electric length thereof is adjusted, so that a predetermined inductive component is generated in the resonance electrode 66. It is designed to be used. Therefore, the second row from the left and 3
In the sets of the resonance electrodes 66, 66 of the third, fourth and fourth steps, and the fifth and fifth steps, the coupling between the resonators is realized by inductive coupling. It should be noted that each of the resonance electrodes 66 located at both ends has the input / output electrodes 68 at the open ends thereof.
A coupling electrode 72 for adding a capacitance is provided between and.

Therefore, even with such a structure, both the capacitive coupling and the inductive coupling are included in the coupling between the resonators (resonance electrodes 66), and therefore, the same effect as the dielectric filter of the above-described embodiment is obtained. You can get it in a grudge.

Further, FIGS. 13 and 14 show still another embodiment of the laminated dielectric filter according to the present invention. As is clear from FIG. 13, the dielectric filter of this example is formed by integrally laminating a total of four dielectric substrates 76 each having a predetermined electrode pattern formed thereon. Specifically, ground electrodes 78 are provided on the upper surface of the first dielectric substrate 76 from the top and the lower surface of the fourth dielectric substrate 76, respectively, and the third dielectric substrate from the top. Four quarter-wavelength resonance electrodes 80 are provided in parallel with each other on the upper surface of 76, and the second dielectric substrate 76 from the top is further provided with the resonance electrodes 80, 80 on the open end side. Input / output electrodes 84, 84 are provided so that the dielectric substrate 76 has the resonance electrode 80 and the corresponding input / output electrode 84 located between them.
Are capacitively coupled via. Thereby,
Corresponding to each of the resonance electrodes 80, four quarter-wavelength triplate resonators are configured.

By the way, in the exemplified dielectric filter, the four-stage resonator (resonance electrode 80) is
Similar to the filter shown in FIGS. 1 to 3 described above,
The groups on both sides are arranged so as to have a combline structure, and the groups at the center have an interdigital structure. In the interdigital structure set, the two resonance electrodes 8
0 and 80 are coupled by inductive coupling by an electromagnetic phenomenon based on the arrangement. On the other hand, in the combline structure set, the coupling electrode 82 is provided on the upper surface of the fourth dielectric substrate 76 from the top at the position where the open ends of the resonance electrodes 80, 80 of each set are connected. Coupling electrode 82
Each of the resonance electrodes 80, 8 via the dielectric layer (substrate 76).
When coupled to 0, the two resonance electrodes 80,
80 is coupled by capacitive coupling.

The four dielectric substrates 76 are laminated and integrated to form an integral dielectric filter, and the side faces of the dielectric filter have upper and lower portions. An electrode for short-circuiting the ground electrodes 78, 78 is burned, and is electrically disconnected from the electrode, and the input / output electrode 8 is also provided.
A pair of input / output terminals are provided at predetermined positions so as to be connected to 4, 84 (see FIG. 1).

Therefore, the equivalent circuit of such a laminated dielectric filter is as shown in FIG. 14, and also by this structure, both the capacitive coupling and the inductive coupling are used for the coupling between the resonators (resonance electrodes 80). Since the above is included, the same effect as that of the dielectric filter of the above-described embodiment can be obtained. Further, in this laminated dielectric filter, the coupling electrode 82 that forms a capacitance is formed in a different layer from the resonance electrode 80, so that a larger capacitance is required or a more complicated equivalent circuit is formed. In some cases, there is an advantage over the dielectric filter shown in FIGS.

The excellent characteristics of the laminated dielectric filter according to the present invention as described above can be clearly recognized in the following test examples.

Test Example 1 The electrode pattern of FIG. 2 was printed with a silver paste on a green sheet made of a material obtained by adding a small amount of glass component or glass powder to a barium oxide-titanium oxide-neodymium oxide compound. Then, this green sheet is sandwiched between a pair of green sheets each having a ground electrode printed on one side, and the green sheets are further laminated between them so as to have a predetermined thickness. Baked at ° C. Then, on the side of the sample, as shown in Fig. 1,
Bake the silver electrode so that the ground electrodes on the front and back are short-circuited,
Further, by providing input / output terminals, the dielectric filter having the structure according to the present invention was completed.

For comparison, the same green sheet is used and the number of resonator stages is made equal, while the resonators are coupled only by inductive coupling (Comparative Example 1) and the resonators. A dielectric filter (Comparative Example 2) in which the coupling was constituted only by capacitive coupling was produced.

When the frequency characteristics of the thus obtained dielectric filter were examined, the center frequency was 838 MHz, the pass band was 32 MHz, and the attenuation outside the pass band was
At 803 MHz, it is 7 more than the dielectric filter of Comparative Example 1.
It was excellent in dB, and at 873 MHz, it was superior to the dielectric filter of Comparative Example 2 by 3 dB.

Test Example 2 A plurality of green sheets made of a barium oxide-titanium oxide-neodymium oxide compound to which a small amount of glass component or glass powder was added were prepared, and each of them is shown in FIG. A series of electrode patterns were printed with silver paste.
Then, the respective green sheets were laminated in the order shown in FIG. 7, and the laminated sample was fired at about 900 ° C. Then, as shown in FIG. 6, silver electrodes were baked on the side surfaces of the sample so as to short-circuit the front and back ground electrodes, and input / output terminals were provided to complete a dielectric filter having a structure according to the present invention.

For comparison, the same green sheet is used and the number of stages of the resonators is made equal, while the coupling between the resonators is made only by inductive coupling. A dielectric filter (Comparative Example 2) in which the coupling was constituted only by capacitive coupling was produced.

When the frequency characteristics of the dielectric filter thus obtained were examined, the center frequency was 840 MHz and the pass band was 35 MHz, and the attenuation outside the pass band was
At 805 MHz, 4 more than the dielectric filter of Comparative Example 1.
It was superior to the dielectric filter of Comparative Example 2 by 6 dB at 873 MHz.

Although some embodiments of the present invention have been described in detail above, it is needless to say that the present invention is not limited by the description of such embodiments. Further, in addition to the above-described embodiments, the present invention may be modified in various ways based on the knowledge of those skilled in the art without departing from the spirit of the present invention. Should be understood.

[Brief description of drawings]

FIG. 1 is an explanatory view schematically showing an example of a laminated dielectric filter according to the present invention.

FIG. 2 is an explanatory view showing an arrangement form of electrodes incorporated in the dielectric filter of FIG.

3 is a sectional view showing a section taken along line III-III in FIG.

FIG. 4 is an equivalent circuit of the dielectric filter of FIG.

5 is a graph showing frequency characteristics of the dielectric filter of FIG.

FIG. 6 is a perspective view showing another example of the laminated dielectric filter according to the present invention.

FIG. 7 is an explanatory diagram showing an arrangement form of electrodes incorporated in the dielectric filter of FIG.

FIG. 8 is an explanatory view showing an arrangement form of electrodes incorporated in a multilayer dielectric filter according to still another embodiment of the present invention.

FIG. 9 is a perspective view showing an example of a conventional coaxial type dielectric filter.

FIG. 10 is an explanatory diagram showing an example of a layout of electrodes incorporated in a conventional triplate-type dielectric filter.

FIG. 11 is a graph showing frequency characteristics that appear in a dielectric filter in which a plurality of resonators are coupled only by capacitive coupling.

FIG. 12 is a graph showing frequency characteristics that appear in a dielectric filter in which a plurality of resonators are coupled only by inductive coupling.

FIG. 13 is an explanatory view showing a layout form of electrodes internally provided in still another multilayer dielectric filter according to the present invention.

FIG. 14 is an equivalent circuit of the dielectric filter of FIG.

[Explanation of symbols]

 20, 40, 60 Dielectric substrate 22, 42, 62 Ground electrode 24, 44, 64 Input / output terminal 26, 46, 66 Resonance electrode 28, 48, 68 Input / output electrode 30, 50, 70 Coupling electrode 32 Coupling Electrode 52 through hole 54 connection electrode 72 coupling electrode 74 electrode 76 dielectric substrate 78 ground electrode 80 resonance electrode 82 coupling electrode 84 input / output electrode

Claims (3)

[Claims] 1. A triplate type line comprising a resonance electrode arranged in a dielectric substrate and ground electrodes provided on both main surfaces of the dielectric substrate, wherein one end of the resonance electrode is opened, and the other. 1 / which is configured by shorting the end to the ground electrode
A multilayer filter characterized in that a four-wavelength triplate resonator is used as a dielectric filter having three or more stages, and the coupling between the resonators is constituted by at least one capacitive coupling and at least one inductive coupling. Type dielectric filter. 2. In a triplate type line composed of a resonance electrode arranged in a dielectric substrate and ground electrodes provided on both main surfaces of the dielectric substrate, one end of the resonance electrode is opened and another 1 / which is configured by shorting the end to the ground electrode
A four-wavelength triplate resonator is used as a dielectric filter having three or more stages, and at least one pair of adjacent resonators are arranged in parallel so that their open ends and shorted ends are in the same direction. , While coupling them by capacitive coupling by adding capacitance between their open ends, at least one pair of adjacent resonators are parallel to each other so that their open and shorted ends are in the same direction. By placing a capacitance between the open end of at least one of the resonators and the ground electrode, and by controlling the coupling electric length of the resonator to a predetermined value, inductive coupling can be achieved. A laminated dielectric filter characterized by being bonded together. 3. In a triplate type line comprising a resonance electrode arranged in a dielectric substrate and ground electrodes provided on both main surfaces of the dielectric substrate, one end of the resonance electrode is opened and 1 / which is configured by shorting the end to the ground electrode
A four-wavelength triplate resonator is used as a dielectric filter having three or more stages, and at least one pair of adjacent resonators are arranged in parallel so that their open ends and shorted ends are in the same direction. , By adding capacitance between their open ends, while coupling by capacitive coupling, at least one pair of adjacent resonators are arranged parallel to each other such that their open ends and shorted ends are staggered By doing so, the laminated dielectric filter is characterized by being coupled by inductive coupling.