JPH01173903A - Dielectric filter - Google Patents

Abstract

PURPOSE:To realize miniaturization and light weight by forming an inner conductor and an outer conductor by conductor films adhered on a dielectric block, coupling the inner conductors mutually by an inner conductor coupling means, and arranging an electrostatic coupling means in the neighborhood of the open terminal of the inner conductor by connecting an input/output inner conductor to the middle way of the open terminal and the short-circuit terminal of the inner conductor. CONSTITUTION:The inner conductor 16 is formed by a conductor film adhered on the inner peripheral planes of plural through holes 14 provided on the dielectric block, and the outer conductor 15 is formed by the conductor film adhered on an outer peripheral plane other than the aperture plane of the through hole 14 of the dielectric block. And on one side of the flat plane and the bottom plane of the dielectric block 13, the inner conductor coupling means 19 is provided, and the input/output inner conductors 17 and 18 are connected to a part on the middle way of a prescribed inner conductor 16, and furthermore, the electrostatic coupling means 8 to be connected to each of the said inner conductors electrostatically is provided, and the electrostatic coupling means 8 is connected to a connection line 9. In such a way, it is possible to realize the miniaturization and the light weight by reducing the number of components and also, making the attachment of the function of a case on the outer conductor unnecessary.

Description

[Detailed description of the invention] [Industrial application field].

The present invention relates to a dielectric filter that is often used in the V)-IF band, UHF band, and microwave band.

[Conventional technology]

FIG. 6 is a cross-sectional view showing a conventional dielectric filter disclosed in, for example, Japanese Utility Model Application Publication No. 57-158203, and FIG. 7 is a vertical cross-sectional view thereof. In the figure, l is an outer conductor that also serves as a case. The main body, 2 is an outer conductor fluid that covers the opening surface of the outer conductor main body 1, and 3 is a plurality of fluids whose length is set to approximately 1/4 wavelength, and which are arranged in the outer conductor main body l, each of which has an outer conductor at one end. an inner conductor which is short-circuited to the bottom of the main body 1 and whose other end is an open end; 4 is a dielectric closely arranged around each inner conductor 3;
Reference numeral 5 denotes a conductor film disposed in close contact with the portion of the dielectric 4 that contacts the outer conductor body l, 6a to 6f denote the outer conductor body l, the outer conductor lid 2. A dielectric material 4 in which an inner conductor 3 and a conductive film 5 are arranged in close contact with each other.
7 is an input/output coupling pattern closely arranged on the surface of the dielectric 4 near the inner conductor 3 constituting the resonators 6a and 6r and coupled to the inner conductor 3; 8 is the resonator 6a; , 6b, 6e, and 6f are closely arranged on the surface of the dielectric 4 near the inner conductor 3 and are coupled to the inner conductor 3, and 9 is a connection line that connects the predetermined coupling patterns 8 to each other. coaxial cable, 10.1
1 is an input/output terminal connected to the human output coupling pattern 7;
Reference numeral 2 designates a frequency adjustment screw which is adjustable and screwed onto the outer conductor lid 2 in correspondence with each inner conductor 3, and whose end faces the open end of the corresponding inner conductor 3.

Next, the operation will be explained. Adjacent resonators 6a to 6f are coupled to each other by magnetic field coupling, and the amount of coupling is adjusted by the distance between adjacent inner conductors 3.

Further, the resonances 56a and 6r and 6b and 60 are coupled by a coaxial cable 9 via a coupling pattern 8 arranged on the surface of the dielectric 4 on the open end side of the inner conductor 3, and input/output terminals 10.11 are connected to the input/output coupling pattern 7 arranged on the open end side surface of the inner conductor 3 of the dielectric 4 of the resonator 6a or 6r, respectively, and are coupled to the resonator 6a or 6r, and the amount of each coupling is It is adjusted by the size of the pattern 8 or the input/output coupling pattern 7.

Now, if all the resonators 6a to 6r resonate at the same frequency, for example fo, by adjusting the length of the inner conductor 3 and the frequency adjustment screw 12, then the frequency f0
In this case, the resonators 6a to 6f in a resonant state are strongly coupled to each other, and the incident wave to the input/output terminal IO is guided to the resonator 6a through the input/output coupling pattern 7, and from the resonator 6f to the input/output coupling pattern. The signal is outputted from the input/output terminal 11 via 7. However, at frequencies other than fo, the resonator 6a
~6f The mutual coupling is very weak, and most of the power of the wave incident on the input/output terminal 10 or 11 is reflected.

In this way, the dielectric filter shown in FIGS. 6 and 7 has a function as a bandpass filter, and the non-adjacent resonators 6a and 6f and 6b and 60 are connected via the coupling pattern 8. They are coupled by a coaxial cable 9, and this coupling is electric field coupling with a different polarity from the magnetic field coupling between adjacent resonators, so an attenuation pole occurs near the passband.
Exhibits steep attenuation characteristics.

[M points while the invention is trying to solve]

Since the conventional dielectric filter is constructed as described above, the outer conductor main body 1 and the outer conductor lid 2 are fitted with the inner conductor 31 and the frequency adjustment screw 12, and function as a case with a mechanically stable structure. In order to satisfy this requirement, a certain degree of wall thickness is required, which hinders miniaturization and weight reduction, and the outer conductor body 1. Outer conductor lid 2, inner conductor 31 frequency adjustment screw 4. Since the dielectric 5 and the like are all separate parts, the number of parts is large, making manufacturing and assembly complicated. Since the filters are placed close to each other, there are problems such as coupling with each other and deteriorating the out-of-band attenuation characteristics of the filter.

This invention was made in order to solve the above-mentioned problems, and it has a small number of parts, is easy to manufacture and assemble, is small and light (can be made into one unit), and also has good out-of-band attenuation characteristics. The purpose is to obtain a dielectric filter having the following properties.

[Means for solving problems]

In the dielectric filter according to the present invention, the inner conductor is a conductive film that is in close contact with the inner peripheral surface of a plurality of through holes formed in a dielectric block, and the outer conductor is a conductive film that is in close contact with the inner peripheral surface of a plurality of through holes formed in a dielectric block, and the outer conductor is a conductive film that is in close contact with the inner peripheral surface of a plurality of through holes formed in a dielectric block. The dielectric block is formed of a conductor film that is in close contact with the surface, and an inner conductor coupling means is provided on at least one of the plane and the bottom of the dielectric block, and an input/output inner conductor is connected to a part in the middle of a predetermined inner conductor. A capacitive coupling means is provided to electrostatically couple with each of the capacitors, and the capacitive coupling means are connected by a connecting line.

[Effect]

The dielectric filter of the present invention has an inner conductor and an outer conductor formed of a conductor film that is in close contact with a dielectric block, and achieves a filter function by the action of the inner conductor coupling means provided on at least one of the plane and bottom surface of the dielectric block. By doing so, the inner conductor.

Integration of the outer conductor and dielectric block reduces the number of parts and facilitates manufacturing and assembly. It eliminates the need for the outer conductor to function as a case, resulting in smaller size and lighter weight. By separating the connecting portion and the capacitive coupling means from each other, the two are prevented from coupling, thereby preventing deterioration of the out-of-band attenuation characteristics.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure and FIG. 2, 8 is a coupling pattern as an electrostatic coupling means, and 9 is a coaxial cable as a connection line, which corresponds to the conventional ones with the same reference numerals in FIGS. 6 and 7. be. Further, 13 is a dielectric block made of a dielectric having a high dielectric constant of t1, and 14 is a dielectric block made from one side of this dielectric block 13, for example, from the front side to the opposite side, which is the back side, parallel to the plane and the bottom side. , a plurality of through holes arranged in parallel to the plane and the bottom surface □;
I5 is an outer conductor made of a conductive film that is placed in close contact with the plane, bottom, left side, right side, and back of the dielectric block 13, and 16 is placed in close contact with the inner peripheral surface of each through hole 14. one end of which is a dielectric block 13.
seamlessly connected to the outer conductor 15 on the back surface of the
Inner conductors 17 and 18, which together with the outer conductor 15 constitute a 1/4 wavelength resonator with one end open and one end short-circuited, are connected to the portion between the open end and the short-circuited end of the inner conductor 1G arranged at both ends. An input/output inner conductor 19 that shunts and extracts a part of the current flowing through the conductor 16 is carved continuously on the plane and bottom surface of the dielectric block 13 in a direction perpendicular to the axial direction of the inner conductor 16. (a groove in which the connected conductor film is closely arranged and acts as an inner conductor coupling means,
The coupling patterns 8 are arranged on the surface of the dielectric block 13 near the open end surfaces of the inner conductors 16 arranged at both ends, and are connected to each other by a coaxial cable 9.

Next, the operation will be explained. This dielectric filter is 1/
Since the open ends of the four-wavelength resonators are arranged on the same side, normally coupling between the inner conductors 16 cannot be obtained, but? By providing R19, coupling between each inner conductor 16 is obtained by the action of the TM mode generated in the electromagnetic field at that part, and the amount of coupling is adjusted by the depth of the groove 19 and the mutual spacing of the inner conductors 16. be able to. Now, by adjusting the length of the inner conductor 16, all the inner conductors 16
are the same frequency f. At that frequency f0, each inner conductor 16 in the resonant state is strongly coupled to the adjacent inner conductor 16 or the input/output inner conductor I7.18, and is connected to the input/output inner conductor 17. An incident wave to an input/output terminal (not shown) is guided to an input/output terminal (not shown) connected to the input/output inner conductor 18. however,
At frequencies other than f0, the coupling between the inner conductors 16 and the coupling between the inner conductors 16 and the input/output inner conductors 17 and 18 is very weak, and the incident wave to the input/output terminal connected to the input/output inner conductor 17 or 18 is very weak. Most of its power is reflected. As described above, the dielectric filter of the present invention has a function as a band-pass filter, and non-adjacent resonators are coupled by the coaxial cable 9 via the coupling pattern 8, and the coupling is transmitted to the adjacent resonators. Since the magnetic field coupling between them is electric field coupling with a different polarity, an attenuation pole occurs near the passband, exhibiting a steep attenuation characteristic, and the input/output inner conductor 17° 18 and the coupling pattern 8 are placed apart in distance. Therefore, they do not combine with each other and deteriorate the out-of-band attenuation characteristics of the filter.

In the above embodiment, a case has been described in which continuous 11W19 is used as the inner conductor coupling means, but this may be replaced by step 20 as shown in FIG. This step 20 also has a conductor film that is seamlessly connected to the outer conductor 15 and is disposed in close contact with the inner conductor 16 in a continuous direction perpendicular to the axial direction of the inner conductor 16. Due to the action of TM mode, the inner conductor I6
By coupling them together, the function of a bandpass filter is realized, and by coupling with the coaxial cable 9 via the coupling pattern 8, a steep attenuation characteristic with good out-of-band attenuation is realized.

Further, FIG. 4 is a perspective view showing still another embodiment of the present invention, and FIG. 5 is a longitudinal sectional view thereof, in which a capacitor is used as the electrostatic coupling means in place of the coupling pattern. In the figure, the second one is the capacitor, and one electrode is directly connected to the open end of the inner conductor 16, and the coaxial cable 9 is connected to the other electrode of this capacitor 21.

The operation of this embodiment is similar to that of the embodiment shown in FIGS. 1 and 2, and in this embodiment the capacitor 21 provides a greater coupling than in the previous embodiment due to the coupling pattern 8.

In the above embodiment, four inner conductors were used and the inner conductor coupling means were provided on both the top and bottom surfaces of the dielectric block. However, it is possible to use a number other than four inner conductors. Alternatively, the inner conductor coupling means may be provided only on one of the plane and bottom surfaces of the dielectric block, and furthermore, the coaxial cable as a connection line may also be provided on the open end surface of the inner conductor of the dielectric block. It is also possible to replace it with a conductor pattern formed of a thick film or the like, and in either case, the same effects as in the above embodiment can be achieved.

〔Effect of the invention〕

As described above, according to the present invention, the inner conductor and the outer conductor are formed of a conductive film closely attached to the dielectric block, the inner conductors are coupled to each other by the inner conductor coupling means, and the input/output inner conductor is connected to the inner conductor by opening the inner conductor. Since the structure is such that the capacitive coupling means is placed near the open end of the inner conductor by connecting it midway between the end and the shorted end, there is no need for the outer conductor to function as a case, making it possible to reduce the size and weight. , frequency adjustment screws, etc. are no longer required, and the components are reduced to just a dielectric block with the inner conductor and outer conductor placed in close contact with each other, and the connection line, which not only simplifies manufacturing and assembly, but also makes it easier to connect the input and output inner conductors. Since the position and the position of the capacitive coupling means are separated from each other in terms of distance, a dielectric filter having steep attenuation characteristics and good attenuation outside the band can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a dielectric filter according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view thereof, FIG. 3 is a perspective view showing another embodiment of the invention, and FIG. 4 is a perspective view showing a dielectric filter according to an embodiment of the invention. FIG. 5 is a vertical cross-sectional view thereof, FIG. 6 is a cross-sectional view showing a conventional dielectric filter, and FIG. 7 is a vertical cross-sectional view thereof. 8 is an electrostatic coupling means (coupling pattern), 9 is a connection line (coaxial cable), 13 is a dielectric block, 14 is a 1" through hole, 15 is an outer conductor, 16 is an inner conductor, 17°!8 is an input 19 is an inner conductor coupling means (groove), 20 is an inner conductor coupling means (step), and 21 is an electrostatic coupling means (capacitor). In the drawings, the same reference numerals indicate the same or equivalent parts.

Claims (5)

[Claims] (1) A plurality of through holes formed from one side in parallel to the plane and the bottom are arranged in close contact with the dielectric block arranged parallel to the plane and the bottom and the inner peripheral surface of each of the through holes. an inner conductor made of a conductor film, and a conductor film disposed in close contact with the outer circumferential surface of the dielectric block, excluding one surface where the through hole is open, and a seam between the inner conductor and one end thereof. an input/output inner conductor connected to a portion between an open end and a shorted end of a predetermined inner conductor; and an input/output inner conductor provided on at least one of the flat surface and the bottom surface of the dielectric block. inner conductor coupling means;
A dielectric material comprising: capacitive coupling means electrostatically coupled to the open end of the inner conductor to which the input/output inner conductor is connected; and a connection line connecting the capacitive coupling means with each other. filter. (2) As the inner conductor coupling means, a groove is used, in which a conductor film seamlessly connected to the outer conductor is disposed in close contact with the inner conductor, and the groove is continuously provided in a direction perpendicular to the axial direction of the inner conductor. A dielectric filter according to claim 1. (3) The inner conductor coupling means is characterized by using a step in which a conductive film seamlessly connected to the outer conductor is closely arranged and continuously provided in a direction perpendicular to the axial direction of the inner conductor. A dielectric filter according to claim 1. (4) As the electrostatic coupling means, a coupling pattern arranged on the surface of the dielectric block near the open end of the inner conductor is used. The dielectric filter according to item 1. (5) As the electrostatic coupling means, a capacitor having one electrode connected to the open end of the inner conductor is used.
The dielectric filter described in section.