JPH07249909A - Dielectric filter and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a compact dielectric resonator having excellent mass- productivity and stabilizing connection between resonators and its manufacturing method. CONSTITUTION:A 1st dielectric board 11 provided with recessed grooves on both the sides and two 2nd plane dielectric bases are prepared and the boards 15, 16 are stuck to the faces having the recessed grooves of the board 11. After the adhesion, inner, outer and short-circuited conductors are formed to obtain a dielectric filter. When plural recessed grooves are formed in parallel on the dielectric boards, many dielectric elements can be manufactured by sticking and cutting off the boards.

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 for manufacturing the same, and more particularly to a small size and excellent mass productivity dielectric filter having a structure in which dielectric substrates are bonded together and a method for manufacturing the same. .

[0002]

2. Description of the Related Art Various dielectric filters are used as high frequency filters. 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 generally used, but a stripline or a laminated LC is used for downsizing. Some types are also used.

The coaxial dielectric resonator has a limit of 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, in order to realize the miniaturization, the inventor has applied for Japanese Patent Application No. 4-1860
In 1999, we proposed a dielectric filter with a structure in which two dielectric substrates are bonded together. This includes a dielectric substrate having a plurality of grooves formed on one surface of a substrate and a flat dielectric substrate bonded together to form an inner conductor, an outer conductor and a short-circuit conductor, and a plurality of dielectric resonators. It is a dielectric filter.

[0004]

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

Further, a manufacturing method in which two dielectric plates are adhered and cut is possible, but since the cutting can be performed only on a plane where the resonators are arranged in a direction parallel to the groove and a direction perpendicular to the groove, mass productivity is improved. In terms of terms, it wasn't enough.

The present invention solves such a problem and provides a dielectric filter suitable for mass production, which is small in size and provides stable coupling.

[0007]

According to the present invention, a dielectric substrate having concave grooves on two opposing surfaces and two flat dielectric substrates are bonded, and a flat dielectric substrate is bonded to the surface having the concave grooves. The above problem is solved by adopting a structure which does not adhere and a method in which the inner surface of the resonator does not adhere to each other.

That is, a flat second dielectric substrate is bonded onto each grooved surface of a first dielectric substrate having a groove extending parallel to one surface and the opposite surface.
Inner conductors are formed in the concave groove and on the surface of the second dielectric substrate facing the concave groove, and the outer conductor is formed on the outer peripheral surface parallel to the extending direction of the concave groove of the first dielectric substrate and the second dielectric substrate. A conductor is formed,
It is characterized in that a short-circuit conductor is provided on one of the end faces where the groove is opened.

Further, a first dielectric substrate having a groove extending parallel to one surface and the surface on the opposite side is arranged so that the groove is positioned in the horizontal direction, and the surface is made vertical. A flat second dielectric substrate is adhered to each of them, and a conductor film is formed in the concave groove and on the surface of the second dielectric substrate facing the concave groove to form an inner conductor. And a conductor film is formed on the outer peripheral surface of the second dielectric substrate parallel to the extending direction of the concave groove to form an outer conductor, and a conductor film is formed on one of the end surfaces where the concave groove is open to form a short-circuit conductor. It is characterized by doing.

[0010]

[Function] Between adjacent resonators, the adhesive parts of the two types of dielectric substrates do not face each other, so there is no dimensional error between the resonators, stable coupling can be obtained, and the area is 30% smaller than in the past. %, About 50% in volume, it is possible to miniaturize. Further, mass production is also possible by forming a plurality of concave grooves for adhering a large number of elements on one substrate, adhering them, and cutting them.

[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 adhering three dielectric substrates to form a predetermined conductor film. A dielectric substrate 11 having concave grooves formed on two facing surfaces is used, and two flat dielectric substrates 15 and 16 are adhered to the surfaces having the concave grooves, respectively, and integrated. Blocks are constructed.

A conductor film is formed on the inner surface of the through holes 17 and 18 formed in the recessed groove portion to serve as an inner conductor. Further, a conductor film is formed on the outer peripheral surface parallel to the extending direction of the concave groove to form an outer conductor. A conductor film (not shown) is formed on one of the surfaces where the through holes 17 and 18 are opened to form a short-circuit conductor, and the opposite end surface is an open end surface where the dielectric is exposed. Usually, a part of the outer conductor is removed and the terminal electrode 19 is formed in that part.

FIG. 2 is a perspective view of a dielectric filter according to the present invention before assembly, which is a dielectric substrate 21 having concave grooves 23 and 24.
Bonding the two flat plate dielectric substrates 25 and 26 is the same as in the above example.

Further, a conductor film 29 for input / output can be formed on the bonding surface of the flat dielectric substrates 25 and 26. The conductor film 29 may be formed so as to be connected to the inner conductor at the impedance matching point, or may be structured to be capacitively coupled to the inner conductor. This conductor film 29 is used for the dielectric substrate 2
It is advisable to pull out to the end faces of 5, 26, and after assembly, connect to the terminal electrode 19 shown in FIG.

If the positions of the concave 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 can be positioned within this width on the opposing surface even if the other groove is displaced. . In this way, by changing the width of the surface of the surface on the opposite side of the groove facing the groove, it becomes easier to match the width of the surface facing each other, and the positional deviation caused by problems in processing accuracy, that is, coupling It is possible to correct the variation in the state.

FIG. 3 is a perspective view showing the manufacturing method of the present invention. A dielectric substrate 51 in which a plurality of parallel concave grooves are arranged at a predetermined interval has two concave grooves facing each other in the horizontal direction, and a flat dielectric substrate is provided on each surface having the vertical concave grooves.
After bonding 55 and 56, 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 dielectric filters can be cut out from a set of bonded blocks. It is advisable to form the above-mentioned input / output conductor film before bonding.

The present invention has three elements (dielectric resonator).
It goes without saying that it can be applied to the above dielectric filters. Further, as described above, dielectric substrates having different concave groove sizes may be bonded together, and in this case, even if a positional deviation occurs, it is possible to prevent variations in the bonding state and obtain a stable bonding state. To be

[0019]

According to the present invention, only the formation of the concave groove in the dielectric substrate poses a processing problem, which is advantageous in terms of downsizing the dielectric filter. Since it is possible to form a groove with a depth of about 0.5 mm on both sides of a substrate with a width of 2 mm and a thickness of 1.5 mm, if the thickness of the flat dielectric substrate is 0.5 mm, the two-element dielectric filter The cross-sectional area can be around 3.0mm x 1.5mm.

In the manufacturing process, except the formation of the conductor film,
Since only the bonding and cutting of the dielectric substrate are required, the number of steps can be reduced, and if a dielectric substrate having a large area is used, a method of manufacturing a dielectric filter having extremely high mass productivity can be realized.

Further, since the adhesive such as glass on the adhesive surface does not flow out to the opposing surface of the inner conductor of the resonator, the distance between the inner conductors of the resonator becomes constant and the influence of the dispersion of the distance is exerted. Since it can be made difficult, a dielectric filter having stable characteristics such as coupling between resonators can be obtained.

[Brief description of 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, 21, 51: Dielectric substrate (with concave groove) 15, 16, 25, 26, 55, 56: (Plate) dielectric substrate

Claims (5)

[Claims] 1. A flat second dielectric substrate is adhered onto each grooved surface of a first dielectric substrate having a groove extending parallel to one surface and an opposite surface thereof to form a groove. An inner conductor is formed in the groove and on the surface of the second dielectric substrate facing the concave groove, and an outer conductor is formed on the outer peripheral surface parallel to the extending direction of the concave groove of the first dielectric substrate and the second dielectric substrate. And a dielectric filter having a short-circuit conductor on one of the end faces where the groove is formed. 2. An input / output conductor pattern is formed on an adhesive surface of a second dielectric substrate, and these conductor patterns are extended to an outer peripheral surface and connected to a terminal electrode insulated from an outer conductor. The dielectric filter described. 3. The dielectric filter according to claim 1, wherein the concave grooves formed on both surfaces of the first dielectric substrate have different widths. 4. A flat second dielectric substrate is adhered onto each grooved surface of a first dielectric substrate having grooves extending parallel to one surface and the opposite surface to form a concave surface. A conductor film is formed in the groove and on the surface of the second dielectric substrate facing the groove to form an inner conductor, and the inner conductor is parallel to the extending direction of the groove of the first and second dielectric substrates. A method for manufacturing a dielectric filter, wherein a conductor film is formed on the outer peripheral surface to form an outer conductor, and the conductor film is formed on one of the end surfaces where the concave groove is opened to form a short-circuit conductor. 5. A flat second dielectric substrate is bonded onto each grooved surface of a first dielectric substrate having a plurality of parallel grooves on one surface and on the opposite surface. A plurality of dielectric blocks are formed by cutting an intermediate portion between the recessed grooves in a direction perpendicular to the bonding surface, and the inside of the recessed grooves of each dielectric block and the recessed groove of the second dielectric substrate An inner conductor by forming a conductor film on the surface facing the outer conductor, and by forming a conductor film on the outer peripheral surfaces of the first dielectric substrate and the second dielectric substrate parallel to the extending direction of the concave groove, the outer conductor is formed. And a conductor film is formed on one of the end faces where the groove is opened to form a short-circuit conductor.