JPH01293701A - high frequency 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 a high frequency filter used in electronic equipment, particularly for the UHF band.

Conventional technology λ/2 type resonant circuits and λ/4 type resonant circuits are usually used as high frequency filters for the υIF band, but in both cases, a wavelength shortening capacitor is connected to one or both sides of the resonant line. are doing. Still another example is one constructed using a helical coil in which a λ/2 length copper wire is wound around a bobbin.

Problems to be Solved by the Invention As described above, in any case, the conventional examples required a length of λ/4 or more, and there was a problem that miniaturization was not possible.

It is an object of the present invention to solve these problems and to provide a high frequency filter whose filter characteristics can be adjusted.

Means for Solving the Problem In order to solve this problem, the present invention provides a plurality of approximately U-shaped resonant lines in the center of a dielectric substrate, and connects a capacitor so that the cut portion of the resonant line is exposed to the outside. For installation, create a tuned circuit by connecting a capacitor to the cut part of the resonant line by providing multiple openings, and also providing multiple openings for adjusting the filter characteristics so that a part of the resonant line is exposed to the outside. The configuration is such that there are separate

Effect With this configuration, it is possible to obtain a high frequency filter with a resonant line having a length of λ/4 or less. This means that the filter characteristics can be adjusted.

Example An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a first tuning circuit provided in the center of a dielectric substrate, and this first tuning circuit 1 includes a resonant line 11 made of a substantially U-shaped conductor, and a disconnection of this resonant line 11. Part 1
4 is connected to a capacitor 7, and an external connection terminal 4 is connected to one end of this cutting portion 14 via a capacitor 6. Further, 2 is a second tuning circuit provided in the center of the dielectric substrate, and this second tuning circuit 2 includes a resonant line 12 made of a substantially U-shaped conductor, and a cut portion of this resonant line 12. 16 and a capacitor 8 connected thereto. Furthermore, 3 is a third tuning circuit provided in the center of the dielectric substrate. Furthermore, an external connection terminal 6 is connected to one end of the cut portion 1e via a capacitor 1o. The resonant line 11 is formed with a deleted part 17 by filter characteristic adjustment, the resonant line 12 is similarly provided with a deleted part 18, and the resonant line 13 is provided with a deleted part 19.

And the first. Second. The third tuning circuit 1.2.3 is arranged in a straight line.

FIG. 2 is a top view of this high frequency filter, in which openings 23, 24, 25, 26, 27 for capacitive weighting are provided, and openings 20, 21, 22 for adjusting filter characteristics are provided.

FIG. 3 is a cross-sectional view of this high frequency filter, in which 3o is a dielectric substrate, and in the center of this dielectric substrate 3o there is a first .
Second. A third tuning circuit 1, 2.3 is formed, and conductors 28, 29 are provided on the entire surface of the main surface and the entire surface of the other surface, and these conductors 28, 29 are used as ground conductors.

The filter characteristics of the high frequency filter with this configuration are as follows:
From B in the figure, the central resonant line 11, 12, 13 of the dielectric substrate 30 is removed from the filter characteristic adjustment openings 20, 21, 22 to the desired characteristic, and removed portions 17, 18, 19 are provided to allow resonance. Adjust the filter characteristics by changing the line dimensions.

In the above embodiment, three tuning circuits 1 to 3 are provided, but it goes without saying that the number of tuning circuits may be two or four or more.

Effects of the Invention As described above, according to the present invention, by providing a plurality of tuning circuits in the center of a dielectric substrate and providing openings for adjusting filter characteristics, it is possible to easily create a compact filter with stable filter characteristics. Furthermore, since the outside of the high frequency filter is grounded over a wide range, it is less susceptible to electromagnetic influences from outside, which is of great industrial value.

[Brief explanation of the drawing]

FIG. 1 is a plan view of the central part of a high-frequency filter according to an embodiment of the present invention, FIG. 2 is a plan view of one main surface of a high-frequency filter according to an embodiment of the present invention, and FIG. FIG. 4 is a sectional view of the high frequency filter according to the embodiment, and a characteristic diagram of the high frequency filter of the present invention. 1...First tuned circuit, 2...Second tuned circuit, 3...Third tuned circuit, 4.6...
...External connection terminal, 6.7.8.9.10...
... Capacity, 11.12゜13 ... Resonance line, 1
4.15.16... Cutting section, 17.18.19
. . . Deletion portion, 20, 21. 22 . . . Filter characteristic adjustment opening, 23, 24. 25, 28, 27...opening for capacitor bottle, 28°29...conductor, 30...dielectric substrate. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 4
Zuto Hji [Nyo E (MHz)

Claims (1)

[Claims] Multiple approximately U-shaped resonant lines are provided in the center of the dielectric substrate,
Multiple capacitor installation openings are provided so that the cut portion of the resonant line is exposed to the outside, and each capacitor is connected to the cut portion of the resonant line to form a tuned circuit, and a portion of the resonant line is also exposed to the outside. A high frequency filter that has multiple exposed openings for adjusting filter characteristics.