JPH03150903A - Dielectric filter - Google Patents

Abstract

PURPOSE:To obtain a dielectric filter which is of low cost, compact and highly reliable by ensuring a common plane to each resonator and forming an input output pattern and a polarized pattern on the plane. CONSTITUTION:One end of resonator slots 11-15 and coupling slots 16-19 reaches the side face of a dielectric base 10, while the other end is terminated on the way to the side face. Metallized conductor plating is applied in the resonator slots 11-15 and a short-circuit end connecting to the conductor layer 20 is formed at the end reaching the side face of the dielectric base 10 and the other end forms an open end. Input output patterns 22, 23 and a polarized pattern 24 comprising the metallized conductor layer are formed on the upper face of the dielectric base 10 by utilizing a space in common to each resonator formed by terminating each slot on its way. Thus, the manufacture cost is reduced and the reliability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a dielectric filter used in a transmitting/receiving circuit of, for example, a car telephone.

[Conventional technology]

For example, dielectric filters are used as filters in transmitting and receiving circuits in mobile radio communications such as car telephones and multi-channel access radios, and furthermore in microwave multiplex radio communications. As this kind of dielectric filter,
In a dielectric filter in which a strip conductor and a ground conductor are integrally formed with a conductive film closely adhered to a dielectric substrate, the fifth
As shown in the figure, a plurality of resonator grooves 41, 42, and 43 are provided on a dielectric substrate 40, which has a conductive layer (matte patterned portion) that is at ground potential on each side and bottom surface, and in each resonator groove. In this case, strip conductors 44 and 45° 46 having one end connected to the conductive layer and the other end open are formed so that the open ends are oriented in the same direction, and a capacitor is connected to the open end side of these strip conductors. It has already been proposed to provide 47 and 48 for inter-stage coupling (
(Japanese Patent Application Laid-Open No. 61-161801). In this known dielectric filter, one stage of resonator is constructed for each resonator groove 41, 42, 43, and interstage coupling is performed by a capacitor 47, 48 provided at the open end side of the strip conductor. . As illustrated in FIG. 6, the terminal as a dielectric filter can be formed by leading out four tabs in the longitudinal direction from the strip conductor 44, or by using a strip 50 formed on the dielectric substrate 40 at right angles to the resonator groove. This is done by connecting tabs (lead wires) not shown in FIG. 5).

[Problem to be solved by the invention]

In the above dielectric filter, since there is no common plane on both sides of the resonator groove on the dielectric substrate, it is impossible or difficult to form any conductive layer pattern on the dielectric substrate. Conventionally, therefore, a configuration has been adopted in which separate printed circuit boards with predetermined patterns are arranged side by side and connected to each other. In addition, as mentioned above, the only way to derive the terminal is to form a conductive layer on the dielectric substrate and connect the tab (lead wire) to it, or to derive the tab from the resonator groove. However, the only option was to attach a tab to the top surface of the dielectric substrate.

An object of the present invention is to provide 12 dielectric filters that can be easily and freely patterned with a cover pattern, a polarization pattern, etc. on a dielectric substrate.

[Means to solve the problem]

In order to achieve the above object, the present invention forms resonator grooves and coupling grooves alternately on the upper surface of a dielectric substrate, substantially perpendicular to the longitudinal direction of the substrate, and furthermore, the convex groove is formed on one side of the dielectric substrate. It has a structure that starts from one side and does not penetrate to the other side.
A conductive layer is applied to the resonator groove and the side and bottom surfaces of the substrate, and a cover pattern and a polarized pattern made of the conductive layer are formed on the other side of the upper surface of the dielectric substrate, with at least one end facing the resonator groove. This is a dielectric filter constructed using the following methods.

[For production]

In the above dielectric filter, on the top surface of the dielectric substrate,
By creating a structure in which the resonator groove and coupling groove start from one side of the dielectric substrate and do not penetrate to the other side, a common plane is secured for each resonator, and input/output patterns and polar Since the structure was designed to form a pattern of
A compact and highly reliable dielectric filter can be provided without increasing manufacturing costs.

〔Example〕

FIG. 1 shows an embodiment of a dielectric filter according to the present invention. In this dielectric filter, the dielectric substrate 10 has resonator grooves 11, 12, 13 running in the width direction thereof,
14, 15 are arranged in parallel along the longitudinal direction, and coupling grooves 16, 17, 18, 19 are arranged between adjacent shaker grooves. On the dielectric substrates 12.13 and 14.15, metallized conductive layers 20 are formed, respectively, as shown by the satin pattern. The bottom and side surfaces of the dielectric substrate 10 are covered with a lid 2.
1 and is used at ground potential. Resonator groove 11
15 and coupling grooves 16 to 19, one end of each reaches to the side surface of the dielectric substrate 10, and the other end terminates halfway to the side surface. A conductive layer made of metallization is applied inside the resonator grooves 11 to 15, and one end thereof reaching the side surface of the dielectric substrate 10 is connected to the conductive layer 20 to constitute a short-circuited end, and the other end constitutes an open end. There is. An input/output pattern 2223 and a polarized pattern 24 made of a metallized conductive layer are formed on the upper surface of the dielectric substrate 10 by utilizing the space common to each resonator created by terminating the convex groove midway. has been done.

One ends of the input/output patterns 22 and 23 face the ends of the resonator grooves 11 and 15 located at both ends, respectively, and the other ends terminate at both ends of the dielectric substrate 10, respectively. Terminal pins 2 are provided at both ends of the dielectric substrate 10, passing through the dielectric substrate 10.
5.26 is provided, and the input/output pattern 22.23
is connected to it. As shown in FIG. 2, the portions of the bottom surface of the dielectric substrate 10 through which the terminal pins 25 and 26 pass are configured as non-conductive portions 28 in which no conductive layer is provided. Both ends of the polarized pattern 24 are
In the embodiment of FIG. 1, the second and fourth resonator grooves 12.
It is facing 14. Although the ground pin is not shown,
It can be provided at one end or both ends of the dielectric substrate 10 in parallel with the terminal pins 25 and/or 26.

According to the above configuration, the cover turns 22 and 23 formed on the dielectric substrate 10 and the resonator groove 11 facing thereto
．． 15 and between the polarized pattern 24 and the conductive layer of the resonator groove 12.2 facing it, capacitance is formed between the input and output patterns 22.
3, the input/output terminals are derived from the first and fifth resonators via capacitance coupling, and the polarized pattern 24 is connected to the capacitive part that couples with the second and fourth resonators, and the transmission that connects them. White polarization due to the line portions is achieved by conductive patterns provided on the upper surface of the dielectric substrate 10, respectively. In this way, polarization can be achieved without arranging terminal tabs on the top surface of the dielectric substrate 10 or arranging tabs along the resonator groove, and without providing a separate printed circuit board. A dielectric filter can be constructed.

The present invention can also be applied to a step impedance type dielectric filter, which is a known type in which a circular resonator hole is formed in a dielectric block. FIG. 3 shows an embodiment in which the present invention is applied to such a step impedance type. A feature of this embodiment is that the resonator grooves 31, 32 are configured in a stepped impedance type, that is, a stepped type.

In this type of dielectric filter, an undesirable peak of characteristic line called triple harmonic occurs at three times the center frequency. This third harmonic wave can be an obstacle depending on the field of application, so it can be solved by shifting it. A step impedance type dielectric filter is used as a stage for shifting such third harmonic waves.

In the embodiment of FIG. 3, the resonator groove 31. The cross section of 32 is large on the population side that is open to the side, and small on the return port side that is closed to the side. On the contrary, it is also possible in principle to make the cross-section of the resonator grooves 31, 32 smaller on the population side that is open to the side surfaces and larger on the population side that is closed to the side surfaces. .

According to the embodiment of FIG. 3, the so-called 3-Δ waves can be easily shifted.

FIG. 4 shows a third embodiment of the invention. In this embodiment, capacitance coupling between the resonator formed by the resonator groove 11 and the Ota cover pattern 22 is performed by a chip capacitor 36, and the resonator formed by the resonator groove 12 and the polarized pattern 24 are A chip capacitor 37 provides capacitance coupling between the two. In this way, it goes without saying that the capacitance coupling between each pattern and the resonator can use a separate capacitor without using the dielectric substrate 10 as a capacitance element.

As described above, by forming the input/output pattern and the polarized pattern on the same dielectric substrate as the resonator, manufacturing costs can be reduced and reliability can be improved.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, there is no need to arrange terminal tabs on the top surface of the dielectric substrate or tabs along the resonator groove, and moreover, it is possible to use a separate printed circuit board. A polarized dielectric filter can be easily constructed without providing a polarized dielectric filter.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of the present invention, and FIG. 2 is a perspective view showing one embodiment of the present invention.
FIG. 3 is a perspective view showing the second embodiment of the present invention, FIG. 4 is a perspective view showing the third embodiment of the present invention, and FIG. 5 is a conventional FIG. 6 is a perspective view of a main part showing a conventional terminal lead-out section. 10...Dielectric substrate, 11, 12.1B, 14°15
．． 31.32...Resonator groove, 16.17, 18°19
...Coupling groove, 20... Conductive layer, 22.23... Input/output pattern, 24... Polarized pattern, 25.26
...Terminal pin, 36°37...Chip capacitor.

Claims (1)

[Claims] 1. Resonator grooves and coupling grooves are formed alternately on the upper surface of the dielectric substrate, substantially perpendicular to the longitudinal direction of the substrate, and each groove starts from one side of the dielectric substrate and does not penetrate to the other side. a conductive layer formed by metallization on the resonator groove and the side and bottom surfaces of the substrate, and further comprising a conductive layer on the other side surface side of the upper surface of the dielectric substrate with at least one end facing the resonator groove. A dielectric filter with an input/output pattern and a polarized pattern.