JP2006340141A - Manufacturing method of dielectric waveguide filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a dielectric waveguide filter with which productivity is improved without need of a complicated process such as grooving, and high-accuracy filter characteristics is provided. <P>SOLUTION: A conductor pattern having a window for coupling is formed on a composition surface of a plurality of dielectric substrates, the plurality of dielectric substrates are bonded, the bonded dielectric substrates are cut vertically to their surfaces to form a plurality of dielectric blocks each internally comprising a conductor pattern, an input/output conductor pattern is formed on one of cross sections, and a conductor film is formed over the relevant cross section other than a portion where the input/output conductor pattern is formed, and over the other three cross sections. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a dielectric waveguide filter used in a microwave band to a millimeter wave band, and particularly relates to a highly accurate manufacturing method suitable for mass production.

  A dielectric waveguide filter is realized by coupling a plurality of dielectric waveguide resonators, and is used as a high-frequency filter. There are roughly two types of methods for configuring this dielectric waveguide filter. One is a method in which individual dielectric waveguide resonators are joined and formed, and this is mainly a microwave of about 2 GHz to about several tens of GHz, which increases the size of the resonator. The other is to provide some discontinuities in the dielectric waveguide by machining, etc., and operate the section delimited by the discontinuities as a resonator, which makes the resonator smaller It is often used in the quasi-millimeter wave band and millimeter wave band of more than a dozen GHz.

FIG. 9 is a perspective view showing a structure in which individual independent resonators are combined. The coupling between the resonators is adjusted by a coupling (adjustment) electrode pattern formed on the side surface (bonding surface). In this case, since conductor films are formed on the surfaces of individual rectangular parallelepiped dielectrics, they are joined together, so that the assembly work becomes complicated. FIG. 10 is a perspective view showing a type in which several discontinuous portions are formed in a dielectric waveguide (block) and a portion sandwiched between the discontinuous portions operates as a resonator. In the case of FIG. 10, four grooves are formed by forming five grooves (generally called iris) on the side surface of the dielectric waveguide. In order to obtain a sufficiently accurate resonance frequency and coupling coefficient between resonators in this structure, it is necessary to sufficiently increase the dimensional accuracy of groove processing by machining, which is a big problem in mass production. .
JP 2002-77907 A JP 2003-110307 A

  The problems of the above-described dielectric waveguide filter can be summarized as follows. The dielectric waveguide filter that joins the individual resonators is likely to be misaligned when the resonators are joined, resulting in characteristic fluctuations. In addition, since the number of parts increases, there is a problem that assembling takes time and the production cost increases. On the other hand, the dielectric waveguide filter with a single structure has only one dielectric block and does not need to be assembled. However, the accuracy of the groove processing of the discontinuous portion for forming the resonator is high. Greatly affects the resonance frequency. In order to perform grooving with sufficient accuracy, there is a problem that a great amount of processing time is required. In particular, when quartz or the like having excellent characteristics as a dielectric material in the millimeter wave band is used as a dielectric material, the hardness and brittleness of the material becomes an obstacle to high-precision groove processing, which is a major problem in manufacturing. .

  The present invention provides a method of manufacturing a dielectric waveguide filter that does not require a complicated process such as groove processing, has high productivity, and can obtain highly accurate filter characteristics.

  The present invention solves the above-mentioned problem by cutting the stacked dielectric substrate and dividing it into a number of dielectric blocks instead of joining individual dielectric resonators or performing groove processing. Is. That is, a conductor pattern having a coupling window is formed on the bonding surfaces of a plurality of dielectric substrates, the plurality of dielectric substrates are bonded, and the bonded dielectric substrates are cut in a direction perpendicular to the surface. A plurality of dielectric blocks having conductor patterns are formed inside, a conductor pattern for input / output is formed on one of the cut surfaces, and a portion other than the portion where the conductor pattern for input / output of the cut surface is formed The method is characterized in that a conductor film is formed on the entire surface of the other three cut surfaces.

The effects of the present invention are as follows.
1. By adopting a production method using batch processing, dielectric waveguide filters can be mass-produced at low cost.
2. Since a conductor pattern by photolithography similar to that of a semiconductor manufacturing process can be formed, high-precision filters that do not require adjustment after assembly can be mass-produced.
3. Since a highly accurate conductor pattern can be formed, an iris resonance type dielectric waveguide filter that does not require adjustment after assembly can be produced.

The manufacturing process of the dielectric filter according to the present invention is as follows.
(1) Polishing the substrate and photolithography of the conductor film (2) Adhering (bonding) the substrate
(3) Cutting (4) Input / output conductor pattern formation (5) Earth conductor film formation

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a dielectric substrate. The dielectric substrate used has a predetermined thickness, and the surface is polished and flattened to the extent that photolithography is possible. FIG. 2 is a perspective view showing a process of stacking a plurality of dielectric substrates. In this example, a dielectric waveguide filter having four elements is formed. Conductive patterns 13 for coupling adjustment are formed on the front and back surfaces of four dielectric substrates 10, and thin dielectrics are formed at both ends thereof. The substrate 12 is arranged and sandwiched. Since the formation of the conductor pattern on the surface of the dielectric substrate can utilize a photolithography technique, a highly accurate conductor pattern can be formed.

  The conductor pattern formed on the surface of the four dielectric substrates 10 is a pattern 13 in which windows for exposing the dielectric material are formed vertically and horizontally on the metal film. The conductor pattern on the surface of the two thin dielectric substrates 11 at both ends is also a pattern in which the dielectric is partially exposed. This is because the end of the conductor pattern for input and output is a dielectric waveguide filter. This is to prevent conduction with the earth conductor. The thickness and number of dielectric substrates can be arbitrarily selected according to the characteristics of the filter.

  The dielectric substrates on which the conductor patterns are formed as described above are joined as shown in FIG. A joining method is arbitrary, and a general adhesion or joining technique may be used. The stacked and bonded substrates are cut and separated as shown in FIG. In this step, a multi-wire saw or the like used for cutting a crystal unit can be used, and cutting can be performed collectively with high accuracy. A conductor pattern as shown in FIG. 5 is formed on the end face and inside of each dielectric block 16 cut and separated. That is, in this example, five coupling adjustment patterns are formed inside, and a conductor pattern serving as a ground conductor is formed on the end face except for a part thereof. These conductor patterns are the same as the conductor patterns shown in FIG.

  Input / output conductor patterns are formed on one side of the cut surface of each dielectric block. The input / output conductor pattern may be drawn to a single surface as the bottom conductor strip shown in FIG. The end of the conductor strip is drawn out so as to be in contact with the exposed portion of the dielectric so as not to be connected to the conductor pattern on the end face. A conductor film is formed on the front surface of the remaining three cut surfaces, and a dielectric waveguide filter having an appearance as shown in FIG. 6 is obtained.

  In the above example, the conductor pattern for adjusting the coupling between the resonators is the one shown in FIG. 7A, but the shape thereof can be arbitrarily selected. For example, a simple shape as shown in FIG. 7B or an H shape as shown in FIG. The coupling between the resonators can be adjusted by the position and size of the opening.

  The dielectric waveguide filter manufacturing method according to the present invention can be applied to an iris resonant filter as shown in FIG. A waveguide filter is usually designed so that a half-wavelength or one-wavelength section partitioned by discontinuous parts operates as a resonator. However, in the production method of the present invention, since the conductor pattern can be formed with micron accuracy, the conductor pattern itself can be formed as a resonance element, and the resonance frequency can be controlled with very high accuracy. Therefore, it is easy to configure a filter using the conductive pattern as a resonance element. In this case, the distance between the conductor patterns is about one-fourth of the guide wavelength, and a normal waveguide filter has a size of the entire filter as compared with the one-half distance between the coupling patterns. Can be made smaller.

  The present invention can be applied to all bands of dielectric waveguide filters that can be used from the microwave band to the millimeter wave band.

The perspective view which shows the process of this invention The perspective view which shows the process (conductor pattern formation) of this invention The perspective view which shows the process (adhesion) of this invention The perspective view which shows the process (cutting | disconnection) of this invention The perspective view explaining the state of the conductor film after cutting The perspective view explaining the inside at the time of cutting Plan view showing an example of a conductor pattern for coupling adjustment The perspective view which shows the other Example of this invention. Perspective view showing a junction type dielectric waveguide filter Perspective view showing an integrated dielectric waveguide filter

Explanation of symbols

10, 11: Dielectric substrate
13, 14: Conductor pattern
16: Dielectric block

Claims (3)

Forming a conductor pattern having a coupling window on the joint surface of a plurality of dielectric substrates;
Bond these multiple dielectric substrates,
Cutting the bonded dielectric substrate in a direction perpendicular to the surface to form a plurality of dielectric blocks having a conductor pattern inside,
A dielectric that forms an input / output conductor pattern on one of the cut surfaces and forms a conductor film on the entire surface of the other three cut surfaces other than the portion where the input / output conductor pattern is formed on the cut surface. Method for manufacturing a body waveguide filter. A conductor pattern having a coupling window is formed on the joint surfaces of a plurality of dielectric substrates, and a conductor film is formed on a portion other than the portion in contact with the input / output conductor pattern on the surface other than the joint surface,
Bond these multiple dielectric substrates,
Cutting the bonded dielectric substrate in a direction perpendicular to the surface to form a plurality of dielectric blocks having a conductor pattern inside,
An input / output conductor strip extending to the end face is formed on one of the cut surfaces, and a conductor film is formed on the entire surface of the other three cut surfaces other than the portion where the input / output conductor pattern of the cut surface is formed. A method of manufacturing a dielectric waveguide filter to be formed.   3. The method of manufacturing a dielectric waveguide filter according to claim 1, wherein the thickness of the dielectric substrates at both ends is made thinner than that of other dielectric substrates.

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