JPS6243902A - Triplate type filter - Google Patents

Abstract

PURPOSE:To increase the degree of freedom in design and to reduce the cost by overlapping a resin base formed with an earth electrode on the dielectric base formed with a filter electrode so as to simplify remarkably the processing of the resin base and to make it inexpensive. CONSTITUTION:Other major face of a resin base 20 formed with the earth electrode 14 on one major face is overlapped onto the other main face of a dielectric base 2 where the earth electrode 4 is formed on one major face and the filter electrode 6 is formed onto the other major face. For example, the resin base 20 made of a material such as glass epoxy or 'Teflon(R)' group resin is used, the earth electrode 14 made of a material such as copper is formed on the one major face and the resin base 20 is overlapped on the dielectric base 2 to form a triplate structure. Since the processing of the resin base is very simple and made inexpensive, the degree of freedom in the design of the filter pattern is increased largely and the cost is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a triplate filter using a so-called strip line.

[Conventional technology]

For example, in a bandpass filter using a strip line, in order to ∎ prevent leakage of electromagnetic field, ∎ improve the symmetry of filter characteristics, ∎ increase the dielectric constant and reduce the size, etc. In some cases, it is a triplate type as shown in . In other words, this triplate type filter is
A ground electrode 4 is provided on the entire surface of one main surface, and a comb-shaped filter electrode (resonant electrode) 6 or an input/output electrode 8 is provided on the other main surface.
The other side of the dielectric substrate 2 (i.e., the filter electrode 6
The main surface of the dielectric substrate 12, which has a ground electrode 14 formed on one main surface, is stacked on the other main surface of the dielectric substrate 12. The patterns of the filter electrode 6, input/output electrode 8, etc. are formed by, for example, printing or etching.

[Problem that the invention seeks to solve]

For stripline filters, as shown in FIG. 6, for example, a filter has been proposed in which a chip component 16 such as a chip capacitor is mounted on a pattern such as a filter electrode 6 to adjust the frequency or to reduce the size. (Refer to Utility Application No. 1983-070144). 17 is solder.

In this case, in the case of the tri-plate type as shown in FIG. 5, for example, as shown in FIG. 7, the dielectric substrate 12 must be carved to provide a recess 121 in which the chip component 16 can be accommodated. Dielectric substrate】2
Because it is hard and easily scraped, it is difficult and time-consuming to process, which poses a problem for actual commercialization.

Another problem with the triplate type is that the cost for the dielectric substrate is twice that of a normal (ie, non-triplate) stripline filter.

Therefore, an object of the present invention is to provide a triplate type filter that can solve the above problems.

[Means for solving problems]

The triplate type filter of the present invention includes a dielectric substrate having a ground electrode formed on one main surface and a filter electrode formed on the other main surface, and a resin substrate having a ground electrode formed on one main surface on the other main surface side. The main surface side of the other side is overlapped.

[Effect]

Triplate formation can also be achieved by stacking a resin substrate on which a ground electrode is formed on a dielectric substrate on which a filter electrode is formed. Moreover, since resin substrates are extremely easy to process and inexpensive, the degree of freedom in design is increased and costs can be reduced.

〔Example〕

FIG. 1 is a sectional view showing a triplate type filter according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view thereof. Components equivalent to those in FIGS. 5 to 7 are designated by the same reference numerals and their explanations will be omitted.

In this embodiment, instead of the dielectric substrate 12 described above, a resin substrate 20 made of, for example, glass epoxy, Teflon resin, etc. is used, and the entire surface of one main surface (and also the side surface if necessary) is used. For example, a ground electrode 14 made of copper or the like is formed, and such a resin substrate 20 is stacked on the dielectric substrate 2 described above to form a triplate structure. This resin base vi20 may be, for example, a printed circuit board made of glass epoxy with a copper electrode attached to one side.

Even in such a filter, the effect of preventing electromagnetic field leakage, which is a major feature of the triplate type, can be obtained in the same way as in a filter using a dielectric substrate. In addition, regarding other features of the tri-plate type, such as improving the symmetry of filter characteristics and reducing the size by increasing the dielectric constant, if the dielectric constant of the resin substrate 20 is small, it is better than that of a non-tri-plate type. Since both the upper and lower parts of the resin substrate are slightly inferior to those using dielectric substrates, it is preferable to select a resin substrate 20 having a dielectric constant as large as possible.

The shape of the resin substrate 20 can be selected appropriately depending on the pattern of the filter electrode 6 and the like. for example,
When chip components 16 are mounted on the filter electrode 6 as illustrated in FIG. 6 above, cutouts 201 may be provided in the portions corresponding to each chip component 16, as shown in FIG. 3, for example. Alternatively, as shown in FIG. 4, a hole 202 may be provided in a portion corresponding to each chip component 16, or a depression may be provided in a portion corresponding to each chip component 16, although not shown. Such a resin substrate 20 can be manufactured extremely easily by, for example, molding.

In this way, the resin substrate 20 is much easier to process than the dielectric substrate, so it is easier to design filter patterns, etc. (that is, the degree of freedom in design is increased), and the resin substrate 20 can be used as described above depending on the purpose. It is also possible to use a chip component 16 or the like. Therefore, the ability to respond to various specification requests from users is greatly increased.

Furthermore, since the resin substrate 20 is easy to process, assembly is also facilitated.

Furthermore, since the resin substrate 20 is cheaper than the dielectric substrate, cost reduction is also achieved.

゛ Note that the electrode pattern configurations of the filter electrode 6, the output electrode 8, etc. are not limited to those described above.

For example, the filter electrode 6 may be of an interdigital type instead of the comb type as described above.

〔Effect of the invention〕

As described above, in the present invention, processing of the resin substrate is very simple and inexpensive, so the degree of freedom in designing filter patterns and the like is greatly increased, and costs are also reduced. Therefore, commercialization becomes very easy.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a triplate type filter according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view thereof. FIG. 3 and FIG. 4 are plan views showing examples of resin substrates, respectively. FIG. 5 is a sectional view showing an example of a conventional triplate filter. FIG. 6 is a plan view showing an example in which a chip component is mounted on a filter electrode, and FIG. 7 is a sectional view of a triplate type filter in that case. 2.12... Dielectric substrate, 4, 14... Earth electrode, 6... Filter electrode, 16... Chip component, 20
・・・Resin substrate

Claims (1)

[Claims] (1) On the other main surface side of a dielectric substrate with a ground electrode formed on one main surface and a filter electrode on the other main surface, and on the other main surface side of a resin substrate with a ground electrode formed on one main surface. A triplate type filter characterized by being made up of overlapping layers.