JPH03187501A - Interdigital filter - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an interdigital filter mainly used in the VIIF band, UIIF band, and microwave band.

[Prior Art] Conventionally, there has been a radio wave device of this type as shown in FIG. This figure 5(a) is G, Matthaei
Others, 'MICROWAVE FILTER3, IMP
EDANCE-1[ATcllINGNETWORKS
, AND C0IIPLING SchoRUC
TURES,” PP, 614-625, 1964.
i[cGraw-11i11. In the figure, (1) to (5) are the inner conductors, (6) is the outer conductor, and (
7) and (8) are coaxial terminals, and (9) and (10) are center conductors of the coaxial terminals (7) and (8), respectively. Fifth (
b) The figure is a cross section taken along line B-B in figure 5(a), and shows (1) to (
6) is the same as FIG. 5(a).

One end of the inner conductors (2), (3), and (4) is a short-circuit end.

The other end is an open end, and is supported on the short-circuit end side.

In this interdigital filter, the inner conductor (2)
, (3), and (4) resonate at the same frequency f t+, then the frequency f. In this case, inner conductors (1) and (5) are inner conductors (2) and (3) in a resonant state.

(4), and the incident wave on the coaxial terminal (7) is guided to the terminal (8). However, at frequencies other than fo, the coupling between the inner conductors (1) to (5) is very weak, and most of the power of the wave incident on the coaxial terminal (7) is reflected. In this way, the interdigital filter shown in FIG. 5(a) has a function as a bandpass filter.

[Problems to be Solved by the Invention] Since the conventional interdigital filter is configured as described above, the inner conductors (2) and (3).

(4) Since the open end side is not supported, there is a problem in that it is mechanically unstable due to vibrations and the like. In addition, since the inner conductors (2), (3), and (4) must have a length of at least approximately 1/4 wavelength of the resonant wave, when used at relatively low frequencies such as the UIIF band, the inner conductors (2) ,(
There was a problem that 3) and (4) became long and the filter became large.

This invention was made in order to solve the above-mentioned problems, and it is an object of the present invention to obtain an interdigital filter that is mechanically stable against vibrations, etc., easy to process, and compact. With the goal.

[Means for Solving the Problems] An interdigital filter according to the present invention has two rectangular parallelepiped-shaped dielectric blocks each having a surface parallel to the surface from one side to the other side opposite to this side. A plurality of grooves are provided, a conductor film is closely attached to the bottom surface of each of the two dielectric blocks and two side surfaces parallel to the grooves to form an outer conductor, and a plurality of conductor films are closely attached to the inner walls of the grooves. The plurality of inner conductors and the outer conductor on the bottom surface are alternately short-circuited at one end of the opposite side by a short circuit part of the conductor film, and the two dielectric blocks are connected to each of the plurality of grooves. The dielectric blocks are assembled so that they are symmetrical with respect to the surfaces that are in close contact with each other, and the surfaces provided with the inner conductors are placed in close contact with each other so that they face each other. It is filled with a conductor.

[Function] In the present invention, a plurality of grooves are provided on the surface of each of two rectangular parallelepiped dielectric blocks, and a plurality of inner conductors are formed by closely adhering a conductor film to the inner wall of the groove, and the two dielectric blocks are The blocks are closely attached so that the surfaces provided with the plurality of grooves face each other and the dielectric block is symmetrical to this surface, and the blocks are bonded into the plurality of through holes formed by the opposing inner conductors. Since the inner conductor is filled with a conductor, the inner conductor is mechanically stably supported against vibrations, etc., and processing is facilitated, and the length of the inner conductor is shortened due to the wavelength shortening effect of the dielectric material. Further, the two inner conductors in each of the through holes have the same potential, and the occurrence of unnecessary modes is suppressed.

[Embodiment] FIG. 1 is a block diagram showing an embodiment of the present invention.
The figure is a structural diagram with some parts missing, Figure 2 is a sectional view taken along the line AA in Figure 1,
FIG. 3 is a BB sectional view of FIG. 1.

In the figure (la) ~ (5a), (lb) ~
(5b) is the inner conductor, (6a) and (6b) are the outer conductors, (7a) ~ (lla) (7b) ~ (llb)
are grooves, (12a) and (12b) are dielectric blocks, (13) to (17) are short circuit parts, (18) is an adhesive conductor such as solder or epoxy conductive adhesive,
(19) is the inner conductor (la), (lb) and the outer conductor (
6a), (6b) and an adhesive conductor (18), (20) is an inner conductor (2a)
, (21) is composed of inner conductors (3a), (3b) and outer conductor (6a).

(6b) and an adhesive conductor (18), (22) is an inner conductor (4a), (4b)
), outer conductor (6a), (6b) and adhesive conductor (1
8), and (23) is an inner conductor (5a), (5b) and an outer conductor (6a),
(6b) and an adhesive conductor (18), (24) is a connector plate, and (25) is an inner conductor (la).

(lb) is the through hole, (26) is the inner conductor (2
a) Through hole consisting of +' (2b), (27
) is a through hole consisting of inner conductors (3a) and (3b), (28) is a through hole consisting of inner conductors (4a) and (4b), (29) is an inner conductor (5a),
The through holes PI and P2 consisting of (5b) are input/output terminals.

In addition, in FIG. 1, the adhesive conductor (18) is not shown.

Inner conductor (la) ~ (5a), (lb) ~ (5
b) are dielectric blocks (12a),
(12b) substantially concave grooves (7a) to (ll
It is formed by closely adhering a conductive film to the inner walls of a), (7b) to (11b). Outer conductor (6a)
, (6b) is a dielectric block (12a),
(12b), and grooves (7a) to (lla
) , (7b) to (llb) are formed by closely adhering a conductor film over the side surfaces parallel to (llb).

The short circuit parts (13) to (17) are connected to the corresponding inner conductors (1a) to
(5a), (lb) to (5b) A groove is formed by slightly notching the side surface of the dielectric block at one end, and a conductive film is formed in close contact with the groove. Inner conductor (la) ~
(5a), (lb) to (5b) are connected to the outer conductor (6) by the conductor film at the short circuit parts (13) to (17), respectively.
a) or (6b) and are short-circuited. In addition, the adhesive conductor (
18), the opposing inner conductors (1a) and (lb
).

(2a) and (2b), (3a) and (3b), (4
a) and (4b), (5a) and (5b) are electrically connected to each other, and two dielectric blocks (12a) and (1
2b') are mechanically glued. Input/output terminal PI
, P2, the inner conductor (la), (lb),
(5a) and (5b), the center conductor of the coaxial line is connected via the adhesive conductor (18), and the outer conductor (6a),
(6b) is the outer conductor of the coaxial line on the connector plate (24)
are directly electrically connected to each other via.

Next, the operation will be explained. In the interdigital filter of the present invention shown in FIGS. 1 to 3, the triplate lines (20), (21), and (22) have the same frequency f. If it resonates at f. Here, the triplate lines (19) and (23) are the triplate lines (20) and (21) in a resonant state.

(22), and the incident wave on the input terminal P1 is guided to the output terminal P2. However, at frequencies other than fo, the coupling between the triplate lines (19) to (23) is very weak, and most of the power of the wave incident on the input terminal P1 is reflected. In this way, the interdigital filter shown in FIGS. 1 to 3 has a function as a bandpass filter.

In the interdigital filter of the present invention, a substantially rectangular parallelepiped dielectric block is processed with grooves, and a conductive film is formed in close contact with a predetermined portion of the dielectric block by, for example, baking. Inner conductors (1a) to (5a), (lb) to which are easy to conduct and mechanically stable
(5b) can be formed. In addition, a dielectric block (12a
), (12b), the inner conductor (la) ~ (5a), (lb) ~ (5b)
can be shortened.

In addition, in the wave device having the structure shown in Figs. 1 to 3, the inner conductor (1a
) and (lb) , (2a) and (2b) , (3a)
and (3b), (4a) and (4b), or (
When a potential difference is created between 5a) and (5b), the triplate line (19).

In (20), (21), (22), or (23), an unnecessary mode as shown in FIG. 4(b) occurs in addition to the basic mode shown in FIG. 4(a). In the interdigital filter of this invention, the adhesive conductor (18
) to form through holes (25) to (29).
1a) and (lb), (2a) and (2b), (3a
) and (3b).

Since (4a) and (4b) and (5a) and (5b) are connected and have the same potential, an unnecessary mode as shown in FIG. 4(b) does not occur. Since the adhesive conductor (18) has elasticity, the grooves (7a) to (lla), (
Even if the depths of the inner conductor (1
a) and (lb), (2a) and (2b), (3a)
and (3b).

(4a) and (4b) and (5a) and (5b) are connected simultaneously.

In the above embodiment, the number of pairs of inner conductors is 5, but the number may be 3, 4, or 6 or more, and the same effects as in the above embodiment can be obtained. Moreover, in the above embodiment, the grooves (7a) to (lla).

Although the cross-sectional shapes of (7b) to (11b) are shown as being substantially concave, they may be semi-elliptical or semicircular, and the same effects as in the above embodiments can be achieved.

[Effects of the Invention] As described above, according to the present invention, a plurality of grooves are provided in the surface of each of two rectangular parallelepiped dielectric blocks from one side to the other side opposite to this side in parallel to the surface,
A conductor film is closely attached to the bottom surface of each of the two dielectric blocks and two side surfaces parallel to the groove to form an outer conductor, and a plurality of inner conductors are formed by closely attaching the conductor film to the inner wall of the groove. , the plurality of inner conductors and the outer conductor on the bottom surface are alternately short-circuited at one end of the opposite side by a short circuit part of the conductor film, and the two dielectric blocks are arranged so that the surfaces provided with the plurality of grooves face each other. The two dielectric blocks are combined so as to be symmetrical with respect to the surface of this close contact, and the adhesive conductor is filled into the plurality of through holes formed by the inner conductors facing each other. , the inner conductor is supported mechanically and stably against vibrations, etc., making processing easier.
The inner conductors facing each other and forming the through hole have the same potential, and the length of the inner ring body is shortened due to the wavelength shortening effect of the dielectric material. Therefore, it is mechanically stable against vibrations, etc., easy to process, and has the advantage of being compact.

[Brief explanation of drawings]

FIG. 1 is a partially omitted configuration diagram showing an embodiment of the present invention;
2 is a sectional view taken along line AA in FIG. 1, FIG. 3 is a sectional view taken along BB in FIG. 1, FIG. 4 is a diagram for explaining the operation shown in FIG. 1, and FIG. FIG. 2 is a schematic configuration diagram showing a wave device. In the figure, (la) ~ (5a), (lb)
~(5b) is the inner conductor, (6a), (6b) is the outer conductor, (7a) ~(lla), (7b) ~(l
lb) is a groove, (12a). (12b) is a dielectric block, (13) to (17) are short circuit parts, (18) is an adhesive conductor, (19) to (23) are triplate lines, (24) is a connector plate, (25) to (
29) is a through hole, and PI and P2 are input/output terminals. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] A plurality of grooves are provided on the surface of each of the two rectangular parallelepiped dielectric blocks from one side to the other side opposite to this side surface, and a plurality of grooves are provided in parallel to the surface, and a bottom surface and the grooves are provided on each of the two dielectric blocks. an outer conductor formed by closely adhering a conductor film to two side surfaces parallel to the groove, a plurality of inner conductors formed by adhering a conductor film to the inner wall of the groove, and a plurality of inner conductors and an outer conductor formed by adhering the conductor film to the inner wall of the groove. a short-circuit portion of the conductor film that alternately shorts the conductor at one end on the opposite side, and the two dielectric blocks are brought into close contact with each other so that the surfaces provided with the plurality of grooves face each other, An interdigital filter characterized in that the dielectric blocks are assembled symmetrically with respect to a plane, and a plurality of through holes formed by the opposing inner conductors are filled with an adhesive conductor.