JPH089924Y2 - Dielectric filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a dielectric filter.

(Prior Art) FIG. 3 is an electrical equivalent circuit diagram of a band elimination filter (abbreviation: BEF) as a dielectric fill, in which a high frequency signal is applied to an input terminal IN and then an output terminal.
This filter receives a predetermined filtering action from OUT to output.

The circuit configuration of the band elimination filter for the above filter action is as follows.

The coils L1 to L3 are connected in series in this order between the input terminal IN and the output terminal OUT. The series circuit of the dielectric coaxial resonator R1 and the capacitor C1 and the series circuit of the dielectric coaxial resonator R4 and the capacitor C4 are respectively connected between the input terminal IN and the ground section and between the output terminal OUT and the ground section. Is connected in between. The series circuit of the dielectric coaxial resonator R2 and the capacitor C2 and the series circuit of the dielectric coaxial resonator R3 and the capacitor C3 are respectively connected between the connecting portions of the coils L1 and L2 and the ground portion, and the coils L2 and L3. Is connected between the connection part and the ground part. The capacitor C5 is between the input terminal IN and the ground portion, the capacitor C6 is between the connection portions of the coils L1 and L2 and the ground portion, and the capacitor C7 is between the connection portions of the coils L and L3 and the ground portion. The capacitor C8 is connected between the output terminal OUT and the ground section.

Since the filter action of the band elimination filter having such a circuit configuration is well known, its explanation is omitted.

4 and 5 show the mechanical structure of the above band elimination filter. The band elimination filter has a dielectric substrate CS.
Is provided. An electrode EDI is formed on the entire lower surface of the dielectric substrate CS. A plurality of electrodes ED2 having an area shape corresponding to the capacities of the capacitors C5 to C8 are formed on the upper surface of the dielectric substrate CS and from one end side to the other end side of the dielectric substrate CS. Capacitors C1 to C4 are mounted on the electrodes ED2 on the upper surface of the dielectric substrate CS, respectively.
A coil is placed on the upper surface of the dielectric substrate CS and between the lower electrodes of the capacitors C1 to C4.
L1 to L3 are installed. The coils L1 to L3 are provided between the connecting portions of the electrodes ED2 on the upper surface of the dielectric substrate CS and the lower electrodes of the capacitors C1 to C4, respectively. At both ends of the dielectric substrate CS, the input terminal IN and the output terminal OUT of FIG. 3 are respectively provided.
Input / output terminals T1 and T2 corresponding to are provided.

Each of the dielectric coaxial resonators R1 to R4 has through holes H1 to H4 formed on both end faces thereof, and each of the through holes H1.
One end sides of coupling terminals K1 to K4 are inserted and fixed to the inner peripheral surfaces of to H4, respectively. The other ends of the coupling terminals K1 to K4 are connected and fixed to the upper electrodes of the capacitors C1 to C4 by soldering, respectively.

(Problems to be Solved by the Invention) In the conventional band elimination filter having the above structure, a dielectric coaxial resonator R1 and a capacitor C1 are representatively shown because they handle high frequency signal filters. As explained based on FIG. 6,
The coupling terminal K1 connected between the dielectric coaxial resonator R1 and the upper surface electrode of the capacitor C1 exhibits a considerably large inductance component L _X for the high frequency signal. Moreover, the inductance component L _X fluctuates at a considerable value depending on the length of the coupling terminal K1.

Therefore, when the coupling terminal K1 is soldered S to the upper surface electrode of the capacitor C1, the amount of solder is small as shown in FIG. 7 (a) and large as shown in FIG. 7 (b). And, the substantial length of the coupling terminal K1, that is, the length of the portion where the coupling terminal K1 is not in contact with any of them, changes, and thereby the inductance component L _X greatly differs.

In addition, the thickness of the capacitor C1 differs depending on its capacitance, but as shown in FIG. 8 (a), the capacitance is large and the thickness of the dielectric is thin, so that the coupling terminal K1 is connected to the capacitor C1. When the part that contacts the top surface electrode becomes longer,
The actual length of the coupling terminal K1 is different from that in the case where the capacitance is small and the thickness of the dielectric material is large, and the portion where the coupling terminal K1 contacts the upper surface electrode of the capacitor C1 becomes short as shown in FIG. 8 (b). . As a result, the inductance component L _{X at} the coupling terminal K1 greatly differs.

However, even if the inductance component L _X of the coupling terminal K1 itself with respect to a high frequency signal is considered in the design of the dielectric filter in advance, the amount of soldering or the thickness of the capacitor should be carefully examined and designed. Things are, in fact, very difficult, and as a result,
It was considered unavoidable that the attenuation characteristics of the band-elimination filter and other filter characteristics based on the variation of the length of the coupling terminal and some other deviations from the design were unavoidable.

Therefore, it is an object of the present invention to further improve the filter characteristics by minimizing the fluctuation of the substantial length of the coupling terminal due to the soldering or the thickness of the capacitor.

(Means for Solving the Problems) In order to achieve such an object, the dielectric filter of the present invention has a dielectric substrate, a capacitance electrode, a dielectric coaxial resonator, and a coupling terminal, and a capacitance electrode. Is provided on the dielectric substrate, the dielectric coaxial resonator is arranged such that the end faces thereof face the side faces of the dielectric substrate, and the coupling terminal has one end connected to the dielectric coaxial resonator. In the dielectric filter having the other end connected to the electrode surface of the capacitance electrode with solder or the like, the coupling terminal has a middle portion bent or curved toward the capacitance electrode, and The end side tip is in contact with the electrode surface of the capacitance electrode at a predetermined angle.

In addition, not only the electrode directly formed on the surface of the dielectric substrate itself but also the capacitor is indirectly mounted on the capacitance electrode in the above-mentioned utility model registration claim, The electrodes on the top surface of the capacitor should also be construed to be included. In addition, the above-mentioned utility model registration request should be construed as including one or more parts in the middle.

(Function) Since the other end side tip of the coupling terminal is in contact with the electrode surface of the capacitance electrode at a predetermined angle, when the other end side tip of the coupling terminal is soldered onto the capacitance electrode of the dielectric substrate, As for the solder, the solder adheres only from the tip of the other end to the periphery of the substantially same place. Therefore, no matter where the position where the other end side end contacts the capacitance electrode is on the capacitance electrode, as a result, the substantial length of the coupling terminal between the dielectric coaxial resonator and the capacitance electrode is the amount of solder. Are almost independent of each other, and the variation of the inductance component based on the coupling terminal is suppressed to a small level.

(Embodiment) Although a band elimination filter is used as a dielectric filter in the present invention, it can be similarly applied to other dielectric filters.

The band elimination filter to which the embodiment of the present invention is applied basically has the mechanical structure shown in FIG. 4 based on the circuit structure shown in FIG. Above, the drawing corresponding to FIG. 4 is omitted, and the configuration of the embodiment is shown in FIG. 1 corresponding to FIG.

Hereinafter, a band elimination filter as a dielectric filter according to an embodiment of the present invention will be described with reference to FIG. 1. The total length of the coupling terminal K1 is l. Further, the coupling terminal K1 is such that the remaining second terminal portion K1b is at an angle of 15 ° to 90 ° with respect to the first terminal portion K1a from the one end side to the middle portion at 1 / 5l to 4 / 5l and the capacitor C1 is formed. Of the second terminal portion K1b is in contact with the electrode surface of the upper surface electrode of the capacitor C1 at a predetermined angle. As a result, for example, the end portion of the second terminal portion K1b of the coupling terminal K1 is placed on the upper surface electrode of the capacitor C1 from the state of FIG. 2 (a) as shown in FIG. 2 (b) or FIG. 2 (c). In the case of soldering, the amount of solder S in FIG.
Although the amount of the solder S is large in FIG. 6C, the solder S adheres to the periphery of the second terminal portion K1b without any difference in any case. Therefore, no matter where the end portion of the second terminal portion K1b is brought into contact with the upper surface electrode of the capacitor C1, as a result, the substantial length of the coupling terminal K1 is constant regardless of the amount of solder, The variation of the inductance component L _X based on the coupling terminal K1 is suppressed to a small level. Since the same applies to the other coupling terminals K2 to K4, the description thereof will be omitted.

Further, although the coupling terminal K1 is bent in the above-mentioned embodiment, it may be bent instead of being bent, and the bending or bending portion is not provided at one place as in the embodiment, but is provided at a plurality of places. Good.

(Effects of the Invention) As is apparent from the above description, according to the present invention, the middle portion of the coupling terminal is bent or curved toward the capacitance electrode, and the other end of the coupling terminal is attached to the electrode surface of the capacitance electrode. Since it was made to contact with at a predetermined angle,
Even if the height of the capacitance electrode changes due to changes in the soldering position on the other end of the coupling terminal to the capacitance electrode or the amount of that solder, or the thickness of the capacitor changes, the actual length of the coupling terminal varies. It will be greatly reduced,
As a result, the filter characteristics can be further improved.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a band elimination filter to which an embodiment of the present invention is applied, and FIGS. 2 (a) and 2 (b).
(C) is each sectional drawing of the said important part for each explaining the operation | movement by the same Example. FIG. 3 is an equivalent circuit diagram of the band elimination filter. 4 to 8 relate to a band elimination filter to which a conventional example is applied, and FIG. 4 is a perspective view showing a mechanical structure of the band elimination filter, and FIG.
FIG. 6 is a sectional view of an essential part of FIG. 4, FIG. 6 is a circuit diagram used to explain the inductance component of the coupling terminal in FIG. 5, and FIGS. 7 (a) (b) and 8 (a) ( FIGS. 7 (a) and 7 (b) are sectional views when the above-mentioned connection is made by soldering. FIGS. 8A and 8B are cross-sectional views when the thickness of the capacitor is different. CS ... Dielectric substrate, C1-C4 ... Capacitor, K1-K4 ... Coupling terminals.

Claims (1)

[Scope of utility model registration request] 1. A dielectric substrate, a capacitance electrode, a dielectric coaxial resonator, and a coupling terminal, wherein the capacitance electrode is provided on the dielectric substrate, and the dielectric coaxial resonator has a dielectric end face. The coupling terminals are arranged opposite to each other on the side surfaces of the substrate, and one end of the coupling terminal is connected to the dielectric coaxial resonator and the other end is connected to the electrode surface of the capacitance electrode by soldering or the like. In the filter, the coupling terminal has an intermediate portion bent or curved toward the capacitance electrode, and the other end side tip is in contact with the electrode surface of the capacitance electrode at a predetermined angle. Characteristic dielectric filter.