JP2869332B2 - Dielectric filter and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric filter and a method of manufacturing the same, and more particularly, to a dielectric filter having a small size and excellent mass productivity, and having a structure in which a dielectric substrate is bonded, and a method of manufacturing the same. .

[0002]

2. Description of the Related Art Various dielectric filters have been used as high frequency filters. In general, a coaxial dielectric resonator in which an inner conductor, an outer conductor, and a short-circuit conductor are formed in a dielectric having a through hole is used. Types are also used.

The limit of a coaxial dielectric resonator is about 2 mm square due to molding problems and the like. Further, the laminated LC filter has a small Q, and it is difficult to obtain desired characteristics. Therefore, the inventor has made Japanese Patent Application No. 4-1860 to realize miniaturization.
In 99, we proposed a dielectric filter with a structure in which two dielectric substrates are bonded. This was provided with a plurality of dielectric resonators by bonding a dielectric substrate having a plurality of grooves on one surface of the substrate and a flat dielectric substrate to form an inner conductor, an outer conductor, and a short-circuit conductor. This is a dielectric filter.

[0004]

In the above-described dielectric filter, when the two dielectric substrates are bonded with glass or the like, the adhesive flows out into the concave grooves and the parallel concave grooves face each other. It will adhere to the wall. Since the inner conductor is formed on the surface of the wall surface to which the adhesive has adhered, an error occurs in the interval between the inner conductors, and it becomes difficult to stabilize the coupling between the resonators.

[0005] In addition, a manufacturing method in which two dielectric plates are bonded and cut can be performed. However, since cutting can be performed only on a plane in which resonators are arranged in a direction parallel to the concave groove and in a direction perpendicular to the groove, mass productivity is reduced. It was not enough in terms of terms.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a dielectric filter suitable for mass production, which can obtain a small and stable coupling.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems by employing a structure and a method of bonding a dielectric substrate having a groove and two flat dielectric substrates in combination. Things.

That is, the first dielectric substrate is bonded to the grooved surface of the first dielectric substrate having a groove extending in parallel with one surface and the opposite surface, so that the first dielectric substrate is bonded to the first dielectric substrate. The dielectric substrate and the flat second dielectric substrate are alternately arranged, and an inner conductor is formed in the concave groove and on the surface of the second dielectric substrate facing the concave groove, and the first dielectric substrate and An outer conductor is formed on an outer peripheral surface of the second dielectric substrate parallel to a direction in which the concave groove extends, and a short-circuit conductor is provided on one of the end faces where the concave groove opens.

Further, the first dielectric substrate having a concave groove extending parallel to one surface and the opposite surface and the second dielectric substrate of a flat plate are alternately formed on the first dielectric substrate. The flat plate second dielectric substrate is bonded to the grooved surface so that the inner conductor is formed by forming a conductive film in the groove and on the surface of the second dielectric substrate facing the groove. Forming a conductor film on an outer peripheral surface parallel to a direction in which the concave groove of the first dielectric substrate and the second dielectric substrate extends to form an outer conductor, and forming a conductor on one of the end faces where the concave groove is opened It is characterized in that a short-circuit conductor is formed by forming a film.

[0010]

[Function] Since the bonded portions of the two types of dielectric substrates are less likely to face each other between adjacent resonators, stable coupling can be obtained, and the area is about 30% smaller than in the past.
The size can be reduced to about 50% by volume. In addition, mass production is possible by forming a plurality of concave grooves for obtaining a large number of elements on a single substrate, bonding the grooves, and cutting the grooves.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of the present invention. The dielectric filter 10 is formed by bonding five dielectric substrates to form a predetermined conductor film. Two dielectric substrates 11 and 12 having concave grooves formed on two opposing surfaces are used, and three flat dielectric substrates 13 to 15 are adhered to the surfaces on which the concave grooves are formed, respectively. A flat dielectric substrate is arranged between both ends and a middle of a dielectric substrate having a concave groove to constitute an integrated dielectric block.

A conductor film is formed on the surface of the through holes 16 to 19 formed in the concave groove portion, and becomes an inner conductor. In addition, a conductor film is also formed on the outer peripheral surface parallel to the direction in which the groove extends, and is used as an outer conductor. A conductor film (not shown) is formed on one of the surfaces where the through holes 16 to 19 are opened to form a short-circuit conductor, and the opposite end surface is an open end surface from which the dielectric is exposed. Normal,
A part of the outer conductor is removed, and the terminal electrode 20 is formed in that part.

FIG. 2 is a perspective view before assembling a dielectric filter according to the present invention. The dielectric substrates 21 and 22 having concave grooves are shown in FIG.
And two dielectric substrates 23 and 25 are attached to both ends thereof,
Placing a flat dielectric substrate 24 between the dielectric substrates 21 and 22 is the same as in the above-described example.

An input / output conductor film 31 can be formed on the bonding surfaces of the flat dielectric substrates 23 and 25. The conductor film 31 may be formed so as to be connected to the inner conductor at the impedance matching point, or may be configured to be capacitively coupled to the inner conductor. The conductor film 31 is formed on the dielectric substrate 2
It is preferable to pull out to the end surfaces of 3 and 25, and after assembly, connect to the terminal electrode 20 shown in FIG.

It should be noted that if the positions of the grooves can be accurately formed, it is not necessary to adjust the coupling between the resonators. One of the grooves provided on the opposing surface of the second dielectric substrate is formed wider than the other groove so that the other groove is located within this width on the opposing surface even if the other groove is misaligned. . In this way, by changing the width of the surface opposite to the concave groove on the surface opposite to the concave groove, misalignment caused by a problem in processing accuracy,
That is, it is possible to correct the variation in the coupling state.

FIG. 3 is a perspective view showing the manufacturing method of the present invention. The grooves of the dielectric substrates 51 and 52 in which a plurality of parallel grooves are arranged at predetermined intervals are horizontally arranged, and the flat dielectric substrates 53 to 55 are respectively adhered to the surface having the vertical grooves. After that, the dielectric filter according to the present invention is manufactured by cutting in a direction perpendicular to the bonding surface at a portion between the concave grooves. According to this method, a large number of dielectric blocks for a dielectric filter can be cut out from the bonded block. Prior to bonding, the input / output conductor film as described above may be formed.

It is needless to say that the present invention can be applied to a dielectric filter having three or five elements (dielectric resonators) or more. Further, as described above, the dielectric substrates having different sizes of the concave grooves may be bonded, and in this case, even if the displacement occurs, the variation of the coupling state can be prevented, and the stable coupling state can be obtained. Can be If a single groove is arranged at the end of the dielectric substrate having the groove, an odd number of elements can be formed.

[0019]

According to the present invention, only the formation of a concave groove in the dielectric substrate poses a problem in processing, which is advantageous in terms of miniaturization of the dielectric filter. Since it is possible to form a groove with a depth of about 0.5 mm on a substrate with a width of 3 mm and a thickness of 1 mm,
The cross section of the four-element dielectric filter can be about 4.5 mm × 1.5 mm.

Also, except for the formation of the conductor film, the manufacturing process
Since only the bonding and cutting of the dielectric substrate are performed, the number of steps can be reduced, and the use of a dielectric substrate having a large area can realize a method of manufacturing a dielectric filter with extremely high productivity.

Further, since it is possible to reduce the influence of the outflow of the adhesive such as glass on the bonding surface, it is possible to obtain a dielectric filter having stable characteristics such as coupling between resonators.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing an embodiment of the present invention.

FIG. 3 is a perspective view showing an example of a manufacturing method according to the present invention.

[Explanation of symbols]

 11, 12, 21, 22, 51, 52: Dielectric substrate (with concave groove) 13-15, 23-25, 53-55: (flat) dielectric substrate

Continuation of the front page (56) References JP-A-5-347504 (JP, A) JP-A-2-94901 (JP, A) JP-A-58-123606 (JP, U) JP-A-4-137602 (JP) , U) Hikaru Hei 3-56204 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01P 1/20-1/219 H01P 7/00-7/10 H01P 5/08 H01P 11/00

Claims (5)

(57) [Claims] 1. A first dielectric substrate having a groove extending parallel to one surface and an opposite surface thereof, wherein the first dielectric substrate is bonded to the grooved surface of the first dielectric substrate. The dielectric substrate and the flat second dielectric substrate are alternately arranged, and an inner conductor is formed in the concave groove and on the surface of the second dielectric substrate facing the concave groove, and the first dielectric substrate and A dielectric filter comprising an outer conductor formed on an outer peripheral surface of a second dielectric substrate parallel to a direction in which a groove extends, and a short-circuit conductor provided on one of the end faces where the groove is opened. 2. An input / output conductor pattern is formed on an adhesion surface of a second dielectric substrate at both ends, and the conductor pattern is drawn out to an outer peripheral surface and connected to a terminal electrode insulated from an outer conductor. Item 7. The dielectric filter according to Item 1. 3. The dielectric filter according to claim 1, wherein the width of one of the grooves facing each other on both surfaces of the first dielectric substrate is different from the width of the other groove. 4. A first dielectric substrate having a concave groove extending parallel to one surface and a surface opposite to the first dielectric substrate and a flat second dielectric substrate. A second dielectric substrate of a flat plate is bonded to the surface having the groove so that a conductive film is formed inside the groove and on the surface of the second dielectric substrate facing the groove, thereby forming an inner conductor. Is formed, a conductor film is formed on the outer peripheral surface parallel to the direction in which the concave groove of the first dielectric substrate and the second dielectric substrate extends, and an outer conductor is formed. A method for manufacturing a dielectric filter for forming a short circuit conductor by forming a conductor film. 5. A first dielectric substrate comprising a first dielectric substrate having a plurality of grooves extending parallel to one surface and a surface opposite to the first dielectric substrate and a second dielectric substrate of a flat plate, alternately. A flat plate-shaped second dielectric substrate is bonded to each of the surfaces having the grooves, and a plurality of dielectric blocks are formed by cutting an intermediate portion of the grooves in a direction perpendicular to the bonding surface. Then, a conductor film is formed on the surface of the dielectric block opposite to the groove of the second dielectric substrate to form an inner conductor, and the first dielectric substrate and the second dielectric substrate are formed. A method of manufacturing a dielectric filter, wherein a conductor film is formed on an outer peripheral surface parallel to a direction in which a concave groove extends, an outer conductor is formed, and a conductive film is formed on one of the end faces where the concave groove opens to form a short-circuit conductor. .