JPS63131601A - Strip line filter - Google Patents

Abstract

PURPOSE:To obtain small size and narrow band by arranging a strip line unit between an input unit and an output unit and bringing the lead of each earth electrode in press contact with an earth electrode of an adjacent unit so as to make them conductive mutually. CONSTITUTION:A strip line filter unit 13 is arranged between an input unit 11 and an output unit 12. The earth electrode 19 has lead sections 22, 23 from another main face opposed to a main face of a 3rd dielectric plate 17 toward the side face of the 3rd dielectric plate 17 in parallel with the strip electrode 18 from one major plane. Thus, in the adjacent strip line units 13, 13, a magnetic force of line generated around the strip line electrode 18 of the strip line unit 13 tends to go around the strip line electrode 13 of the strip line unit 13 by the lead sections 22, 22, but part of it is blocked. Thus, the coupling coefficients between the adjacent strip line units 13, 13 are decreased and miniaturization is attained at a narrow band.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a stripline filter used as a bandpass filter in a microwave band or a millimeter wave band.

(Prior art) Generally, as a microwave band or millimeter wave band filter,
Waveguide filters, dielectric filters, strip line filters, etc. are used.

Conventionally, a comb-shaped filter as shown in FIG. 6, for example, is well known as a stripline filter.

The above-mentioned stripline filter is of a band-pass type and consists of a rectangular dielectric plate 1 made of a high permittivity material, and one main surface of the dielectric plate 1 has an input electrode 2, an output electrode 3 and Strip line electrodes 4, 4. ... are formed, and on the other main surface of the dielectric plate l, a ground electrode 5 is formed over the entire surface. Said input electrode 2, output electrode 3 and strip line electrode 4.4.
... extends from one side of one main surface of the dielectric plate 1 toward the other side opposite to this one side. Then, the strip line electrodes 4, 4 . The short-circuit portion 5a of the ground electrode 5 extended to . . . ... are short-circuited to the ground electrode 5.

By the way, in the comb-shaped stripline filter shown in FIG.
is determined by the length e, and is set to Q=λ/4. On the other hand, the passband width of the filter is determined by the coupling coefficient between adjacent stripline electrodes 4.
The smaller the coupling coefficient is, the narrower the passband width becomes. However, the coupling coefficient becomes smaller as the distance S between the adjacent strip line electrodes 4 becomes larger.

Therefore, in the conventional stripline filter shown in FIG. 6, in order to obtain a narrowband filter, the above-mentioned interval S must be increased, which causes the problem that the shape becomes large.

(Object of the Invention) An object of the present invention is to provide a stripline filter with a narrow band and a small size.

(Structure of the Invention) For this reason, the present invention provides a device in which an input electrode and a ground electrode are formed on the bidirectional surfaces of a first dielectric plate, and an output electrode and a ground electrode are formed on the bidirectional surfaces of the second dielectric plate. A stripline filter electrode and a ground electrode are formed on both sides of the third dielectric plate between the output unit and the output unit on which the electrodes are formed, respectively, and the stripline electrode is formed on one end face of the third dielectric plate. A strip line unit is arranged which is short-circuited to the ground electrode by the short-circuit portion, and each ground electrode of the input unit, output unit, and strip line unit is connected to each side of the first dielectric plate to the third dielectric plate. The ground electrodes are electrically bonded to each other at the drawn out portions. The lead-out portion of the ground electrode is strip line 1 of one strip line unit!椛77'l 14*M! -Iegu thi
1 Nafufugo 1”ah< pgμ one θ
)7 Partially prevents the stripline from wrapping around the stripline electrode adjacent to the tripline unit.

This reduces the coupling coefficient between adjacent stripline units.

(Effects of the Invention) According to the present invention, the lines of magnetic force generated around the stripline electrode of one stripline unit are
The lead-out portions of the ground electrodes drawn out on each side of the dielectric plate partially prevent the ground electrodes from going around the stripline electrodes of another stripline unit adjacent to the above-mentioned one stripline unit. Even if the spacing between the stripline electrodes of the line units is reduced, the coupling coefficient between adjacent stripline units can be reduced, and thereby a small-sized stripline filter with a narrow band can be obtained.

(Example) Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

A perspective view of an embodiment of a stripline filter according to the present invention is shown in FIG.

The stripline filter is connected to the input unit 11.
Output unit 12 and multiple stripline units arranged between them! 3. Consists of 13,...
These input units 11. Output unit 12 and stripline unit 13.13. . . . are adhered to each other in the same direction to form a single flat plate.

The human crab knit 11, as shown in FIG. 2(a),
A first dielectric plate 14a having a substantially constant width and an input electrode 1
5a and a ground electrode 16a.

The human-powered electrode 15a is formed on one main surface of the first dielectric plate 14a so as to extend from one end of the one main surface toward the other end in a direction substantially perpendicular to the width direction thereof. . Further, the ground electrode 16a is connected to the first dielectric plate 1
Leading portions 21a, 21 are drawn out to the middle of both side surfaces of the first dielectric plate 14a parallel to the input electrode 15a from another main surface opposite to the one main surface of 4a.
a, while the output unit 12 also has the input unit 1
It has exactly the same configuration as 1. That is, as shown in FIG. 2(a), the output unit I2 includes a second dielectric plate 14b having a substantially constant width, an output electrode 15b, and a ground electrode 16b.

The output electrode 15b is formed on one main surface of the second dielectric plate 14b so as to extend from one end of the main surface toward the other end in a direction substantially perpendicular to the width direction of the second dielectric plate 14b.

Further, the ground electrode 16b extends from the other main surface of the second dielectric plate 14b opposite to the one main surface to the middle of both side surfaces of the second dielectric plate 14b parallel to the output electrode 15b. It has drawn out drawer parts 21b, 21b.

As shown in FIG. 2(b), each stripline filter unit 13 disposed between the input unit 11 and the output unit I2 includes a third dielectric plate 17 having a substantially constant width and a stripline electrode. 18 and a ground electrode 19.

The strip line electrode I8 is formed on one main surface of the third dielectric plate 17 in a direction substantially perpendicular to the width direction thereof, so as to extend from one end of the one main surface toward the other end. There is. Further, the ground electrode 19 is drawn out from another main surface opposite to one main surface of the third dielectric plate 17 to a side surface of the third dielectric plate 17 parallel to the strip line electrode 18. Drawer part 22.2
It has 2. The ground electrode 19 further includes a third dielectric plate [17
It has a short-circuit portion 19a passing through the end face of and reaching the strip line electrode I8.

The first dielectric plate 14a of the input unit 11 explained above
The lead-out portion 21a of the ground electrode 16a formed on the side surface of
, 21a is soldered to one of the lead-out portions 22.22 of the ground electrode 19 formed on the side surface of the third dielectric plate 17 of the strip line unit 13 adjacent to the above-mentioned human crab knit 11. It is glued by. Further, in the two adjacent strip line units 13.13, one of the lead-out portions 22.22 of each of the ground electrodes 19 is bonded to each other with solder or conductive adhesive in the same manner as described above. . Furthermore, a ground electrode 16b formed on the side surface of the second dielectric plate 14b of the output unit 12
One of the lead-out parts 21b, 21b is bonded to one of the lead-out parts 22.22 of the ground electrode 19 formed on the side surface of the third dielectric plate 17' of the output unit 13 by solder or conductive adhesive. Ru. As a result, a stripline filter as shown in FIG. 1 is constructed.

With such a configuration, the lines of electric and magnetic fields of the electric and magnetic fields generated in the stripline electrodes 18 of each stripline unit 13 are shown by dotted lines and solid lines, respectively, in FIG. In unit 13.13, the lines of magnetic force generated around the stripline electrode 18 of one stripline unit 13 are transferred to the stripline electrode 18 of another stripline unit 13 by the lead-out portion 22° 22 of the ground electrode 19. Attempts to sneak around are partially blocked. As a result, even if the spacing between the stripline electrodes 18, 18 of adjacent stripline units 13.13 becomes smaller, the coupling coefficient between them becomes weaker, so that a small and narrow band stripline filter can be obtained.

In the above embodiment, the lead-out portion 22 of the ground electrode 19 of the strip line unit 13 has a constant width, but as shown in FIG. The drawer portion 23 may be formed to extend beyond this range, or, as shown in FIG. 5, a wide portion 24 may be formed in a part of the drawer portion 22. This makes it easy to adjust the coupling coefficient.

Further, in the above embodiment, a 1/4 wavelength type one in which the strip line electrode 18 was short-circuited to the ground electrode 19 at one end was explained, but in the present invention, although not specifically shown, the strip line electrode 18 is short-circuited at both ends. It can also be applied to a 1/2 wavelength type in which the strip line electrodes are open and capacitively coupled to each other.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of a stripline filter according to the present invention, and FIGS. 2(a) and (b) are perspective views of an input/output unit and a stripline unit, respectively, which constitute the stripline filter of FIG. 1. Figure 3 is an explanatory diagram of the operation of the stripline filter in Figure 1, Figures 4 and 5 are side views of modified examples of the stripline unit, respectively, and Figure 6 is a perspective view of a conventional stripline filter. be. 11... Input unit, 12... Output unit, 13... Strip line unit, 14a...
First dielectric plate, 14b...Second dielectric plate, 15a...
...Input electrode, 15b...Output electrode, 16a, 1
6b...Earth electrode, 17...Third dielectric plate, 18...Strip line electrode, 19...Earth electrode, 21a, 2 lb, 22.23-Leader portion, 24...
Wide part. Patent applicant Murata Manufacturing Co., Ltd. Agent Patent attorney Aoyama Aoyama and 2 others wE4 Figure 51! f

Claims (1)

[Claims] (1) An input electrode is formed on one main surface of a first dielectric plate having a substantially constant width, extending from one end of the one main surface toward the other end in a direction substantially perpendicular to the width direction of the first dielectric plate. On the other hand, the ground electrode formed on another main surface opposite to the one main surface of the first dielectric plate has a lead-out portion formed by drawing out the ground electrode to a side surface of the first dielectric plate parallel to the input electrode. An output electrode is formed on one main surface of the input unit and a second dielectric plate having a substantially constant width and extending from one end of the one main surface toward the other end in a direction substantially perpendicular to the width direction of the second dielectric plate. On the other hand, a ground electrode formed on another main surface opposite to one main surface of the second dielectric plate is connected to a second ground electrode parallel to the output electrode.
an output unit having a drawer portion drawn out from a side surface of a dielectric plate; and a third dielectric plate having a substantially constant width, the output unit having a drawer portion extending from the side surface of the dielectric plate; A strip line electrode is formed extending from one end toward the other end, while a ground electrode formed on another main surface opposite to one main surface of the third dielectric plate is parallel to the strip line electrode. a stripline unit having a lead-out portion drawn out from a side surface of a third dielectric plate; and a short-circuit portion formed from an end surface of the third dielectric plate including one end of the one main surface to the stripline electrode. A stripline unit is arranged between the input unit and the output unit, and the lead-out part of each ground electrode of the strip-line unit contacts the lead-out part of the ground electrode of the adjacent input unit, output unit, or stripline unit, so that they are connected to each other. A stripline filter characterized in that it is electrically conductively bonded.