JPH09130110A - Connection terminal for coaxial resonator and dielectric filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a loss that is caused at the connection terminal of a coaxial resonator mounted on a dielectric filter and also in the pass band generated in the vicinity of the connection terminal of the resonator by rounding the edge of a recess corner part of the connection terminal. SOLUTION: A coaxial resonator is provided with a through-hole formed in a dielectric block and the inner and outer conductors formed on the inner and outer circumference surfaces of the through-hole, respectively. A connection terminal which is connected to the inner conductor of the resonator has an inner conductor connection part 11 which is electrically connected to the inner conductor and a circuit connection part 12 which protrudes from one of both ends of the part 11 and is connected to an electric circuit element or a circuit pattern formed on a printed circuit board. Then the recess corner part of a coupling part between both parts 11 and 12 are subjected to the rounding 13. In such a constitution, the loss of the working circuit element is minimized and the loss, if caused, despite an ideal circuit design can be improved. Thus the smaller insertion loss is attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency loss reduction method for a dielectric filter used in high frequency wireless communication and the like.

[0002]

2. Description of the Related Art As a connection terminal of a coaxial type resonator used in a conventional dielectric filter, for example, an actual open circuit 59-1 is used.
There are connection terminals as shown in 54906. This conventional connection terminal will be described with reference to FIG. A cylindrical inner conductor connecting portion 1 for connecting to an inner conductor provided on the inner peripheral surface of the through hole of the coaxial resonator, and a circuit extended at one end side of the inner conductor connecting portion for joining to an electric circuit element. There is a joint 2.

Further, it has a supporting portion protruding from one end of the inner conductor connecting portion, and a circuit connecting portion branched from the supporting portion for connecting to an electric circuit element or a circuit pattern on a wiring board. As a conventional example of the shaped connection terminal, there is a connection terminal as disclosed in Japanese Patent Application No. 6-203489 filed by the applicant of the present application. Regarding this connection terminal, FIG.
This will be described with reference to FIG. A cylindrical inner conductor connecting portion 1 for electrically connecting to an inner conductor formed on the inner peripheral surface of the through hole of the coaxial resonator, and a supporting portion 3 protruding from one end side of the inner conductor connecting portion are provided. In addition, it has a circuit joint portion 2 which is branched and extended in two for joining with an electric circuit element.

These connection terminals are joined to an electric circuit element or a board pattern by soldering to form a dielectric filter. The amount of solder used for joining at this time is
It is customary to minimize it.

[0005]

The characteristics of the dielectric filter are required to have a smaller insertion loss in the signal pass band and a larger attenuation amount in the signal stop band.

Loss = 0 is desirable for the characteristics in the signal pass band, but when a filter is actually manufactured, there are losses in the circuit elements such as the resonator, coil, and capacitor used, so the circuit configuration is Although it depends on the value of the amount of attenuation in the required signal stop band, a loss of about 0.5 dB is usually generated even if the circuit design is ideal, and it is difficult to remove this. When attempting to realize a characteristic of 0.5 dB or less, in addition to the loss of the circuit element used, the equivalent circuit at the circuit design stage, such as the stray capacitance and the connection terminal used for the mounting board and the resonator, etc. Then, the loss ratio that is difficult to express becomes a value that cannot be ignored.

A technical object of the present invention is to provide a connection terminal of a coaxial resonator mounted on a dielectric filter, a connection terminal in which a loss in a pass band generated near the connection terminal is reduced, and a coaxial terminal having the connection terminal. To provide a dielectric filter using a type resonator.

[0008]

In order to realize a very small insertion loss of 0.5 dB or less in a signal pass band which is difficult to realize, the present invention has the following solving means.

A connection terminal for connecting a through hole is formed in a dielectric block, an inner conductor is formed on the inner peripheral surface of the through hole of the dielectric body, and an inner conductor is formed on the outer peripheral surface of the dielectric resonator to the inner conductor of the coaxial resonator. An inner conductor connecting portion electrically connected to the inner conductor,
A circuit joint portion protruding from one end of the inner conductor connecting portion and connected to a circuit pattern on an electric circuit element or a wiring board, and a corner of a concave portion of a connecting portion between the inner conductor connecting portion and the circuit joint portion. The inner conductor connecting portion electrically connected to the inner conductor, the supporting portion protruding from one end of the inner conductor connecting portion, the electric circuit element or the wiring board A circuit joint portion branching from the support portion for connecting to a circuit pattern, and a concave corner portion of a connecting portion between the inner conductor connecting portion and the support portion, and the support portion and the circuit joint portion. A connecting terminal for a coaxial resonator, wherein at least one of the concave corners of the connecting portion is rounded, and a dielectric filter using the coaxial resonator having these connecting terminals. is there.

Further, a connection is formed by forming a through hole in the dielectric block and connecting the inner conductor to the inner peripheral surface of the through hole of the dielectric and the inner conductor of a coaxial type resonator having an outer conductor formed on the outer peripheral surface thereof. The terminal has an inner conductor connecting portion electrically connected to the inner conductor, and a circuit joint portion protruding from one end of the inner conductor connecting portion and connected to an electric circuit element or a circuit pattern on a wiring board. Characterized in that solder is welded so as to round the corners of the concave corners of the connecting portion between the conductor connecting portion and the circuit joint portion, and the inner conductor connecting portion for electrically connecting the connecting terminal to the inner conductor An inner conductor connecting portion, the supporting portion protruding from one end of the inner conductor connecting portion, and a circuit joint portion branched from the supporting portion for connecting to a circuit pattern on the electric circuit element or the wiring board. Corner portion of the connecting portion between the base portion and the support portion, and Solder is welded to round at least one of the concave corners of the connecting portion between the supporting portion and the circuit joint portion, and a dielectric using a coaxial resonator having these connecting terminals. It is a filter.

In addition, the circuit connecting portion of the connection terminal is welded by increasing the amount of solder so that a corner is not formed at a portion to be soldered to an electric circuit element or a circuit pattern on a wiring board. And a method of manufacturing the same.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a filter having a very small pass band loss required in a mobile communication system such as a mobile phone and a digital cordless phone, and a dielectric filter for filtering electromagnetic waves with lower loss. As the connection terminal of the coaxial resonator mounted in, the edge of the concave corner of the connection terminal is rounded, or the solder is welded so that there is no corner at the joint between the connection terminal and the circuit element. The loss characteristics are 30 compared with the conventional one.
% Improvement is possible and insertion loss in a smaller pass band is realized.

(Embodiment) FIGS. 1 and 2 show an embodiment of a connection terminal of a coaxial resonator according to the present invention.

Further, FIG. 3 shows a connection terminal in which the concave corners of the connection terminal shown in FIGS. 1 and 2 are both rounded, and a specific example will be described using this. The connection terminal is formed of a phosphor bronze plate having a thickness of 0.2 mm and is plated with solder. As for the dimensions, the tube diameter of the cylindrical inner conductor connecting portion 11 is 3.0 mm,
The pipe length is 4.0 mm, the width of the circuit joint 32 is 8.7 mm,
The vertical width is 0.5 mm, the longitudinal direction of the support portion 33 is 2 mm, and the horizontal width is 0.5 mm.

The size of the corner rounding 34 applied to the concave corner between the circuit joint and the support is R = 1.0 mm, and the corner rounding applied to the concave corner between the support and the circuit joint. The size of 35 is R = 1.0 mm, which is twice the vertical width of the circuit joint portion and the horizontal width of the support portion.

Next, an embodiment of a dielectric filter using the connection terminal of the embodiment shown in FIG. 3 will be described in FIG. The coaxial resonator 4 is grounded on the mounting board 42. Through holes 41 are formed in the axial direction of these coaxial resonators. Three electrical coupling elements (electrical circuit elements) 43 for coupling a plurality of coaxial resonators are provided and are coupled by a connection terminal 47. The two electric coupling elements provided on both sides are respectively connected to the input / output terminals 44
And a dielectric filter is formed between the input and output terminals.

FIG. 10 shows a circuit configuration of the dielectric filter shown in FIG. As a specific example, the resonance frequency of the two coaxial resonators is 2090 MHz, the capacitance of the electric coupling elements provided on both sides is 0.9 pF, and the capacitance of the electric coupling elements provided in the middle is 0.4 pF. did.

Loss in the pass band of the dielectric filter when using the conventional connection terminal not having rounded corners and when using the connection terminal shown in FIG. 3 in the embodiment of the present invention. , Shown in Table 1.

[0019]

FIG. 5, FIG. 6, FIG. 7, and FIG. 8 show an embodiment of solder welding applied to the connection terminal according to the present invention.

Further, FIG. 9 shows an embodiment of the dielectric filter to which the solder welding shown in FIGS. 5 to 8 is applied, and a specific example will be explained using this. The coaxial resonator 4 is grounded on the mounting board 42. Through holes 41 are formed in the axial direction of these coaxial resonators. Three electric coupling elements 43 for coupling a plurality of coaxial resonators are provided and are coupled by a connection terminal 47. Two electrical coupling elements (electrical circuit elements) 4 provided on both sides
3 are connected to the input / output terminals 44, and a dielectric filter is formed between the input / output terminals. Then, a large amount of solder is applied to the connection portion between the connection terminal and the electric circuit element so that no recessed corner portion is formed (a solder application portion is indicated by 56).

FIG. 10 shows a circuit configuration of the dielectric filter shown in FIG. As a specific example, the resonance frequency of the two coaxial resonators is 2090 MHz, and the capacitance of the electric coupling elements provided on both sides is 0.4 pF.

Table 2 shows the loss in the pass band of the conventional dielectric filter and the dielectric filter soldered as shown in FIG. 9 in the embodiment of the present invention.

[0024]

When it is attempted to realize the characteristic that the pass band loss is 0.5 dB or less, in addition to the loss of the circuit element used,
On the equivalent circuit at the circuit design stage, such as stray capacitance, the mounting board, and the junction terminals used for the resonator, the loss ratio that is difficult to express becomes a value that cannot be ignored. It is not easy to improve the characteristics by improving the circuit design and the loss of the circuit elements used.

It is known that the smaller the shape, the more the loss of the coaxial resonator increases. The structure of the dielectric filter shown in FIGS. 4 and 9 is as large as 10 mm square, but Q A coaxial resonator with a low loss of about 800 is used, and a material with a low loss is selected for the electric coupling element.
Moreover, in order to minimize the stray capacitance and the loss on the mounting board, wiring is not performed on the mounting board. Even in this case, as shown in Tables 1 and 2, the passband loss is 0.
There is a 33 dB loss remaining.

However, the rounded corners of the connection terminals of the coaxial resonator are rounded as shown in FIG.
The 8 dB pass band loss is reduced, and it is possible to improve it by about 30% as compared with the conventional one, and the insertion loss in a smaller pass band is realized.

Further, conventionally, it has been considered desirable to minimize the amount of solder used for connection. However, as shown in FIG. 9, by welding the solder so that there is no corner at the connection portion between the connection terminal and the circuit element, the 0.09 dB pass band loss is reduced, which is about 30% of the conventional value. Improvement is possible and insertion loss in a smaller pass band is realized.

[0029]

As described above, according to the present invention, even if the loss of circuit elements used is as small as possible and the circuit design is ideal, the generated loss is further improved.
It is possible to realize a smaller insertion loss.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a connection terminal of a coaxial resonator according to the present invention.

FIG. 2 is a perspective view showing another example of the connection terminal of the coaxial resonator according to the present invention.

FIG. 3 is a perspective view showing another example of the connection terminal of the coaxial resonator according to the present invention.

FIG. 4 is a perspective view showing a dielectric filter using a connection terminal of a coaxial resonator according to the present invention.

FIG. 5 is a perspective view showing an example of a solder application portion of the connection terminal of the coaxial resonator according to the present invention.

FIG. 6 is a perspective view showing another example of the solder application portion of the connection terminal of the coaxial resonator according to the present invention.

FIG. 7 is a perspective view showing another example of the solder application portion of the connection terminal of the coaxial resonator according to the present invention.

FIG. 8 is a perspective view showing a solder application portion of a joint portion between a connection terminal and a circuit element of the coaxial resonator according to the present invention.

FIG. 9 is a perspective view showing a dielectric filter using a connection terminal of a coaxial resonator according to the present invention.

FIG. 10 is a circuit configuration diagram of a dielectric filter.

FIG. 11 is a perspective view showing an example of a connection terminal of a conventional coaxial resonator.

FIG. 12 is a perspective view showing another example of the connection terminal of the conventional coaxial resonator.

[Explanation of symbols]

1,11 Inner conductor connecting part 2,12,22,32,52,62,72,82 Circuit joining part 3,23,33,73,83 Support part 4 Coaxial resonator 13 (Inner conductor connecting part and circuit joining Recessed corners between parts) Corner rounding 24, 34 (Recessed corners between circuit joint and support) Corner rounding 35 (Recessed corners between support and inner conductor joint)
Rounded corner 41 Through hole (of coaxial resonator) 42 Mounting board 43 Electrical coupling element 44 Input / output terminal 47 Connection terminal 54, 56, 64, 74, 84 Solder welded portion 90 Electrical circuit element

Claims (7)

[Claims] 1. An inner conductor connecting portion for electrically connecting an inner conductor formed on an inner peripheral surface of a through hole of a coaxial resonator to the inner conductor, and the inner conductor connecting portion. And a circuit joint portion for connecting to an electric circuit element or a circuit pattern on a wiring board, and a rounded corner is formed at a concave portion formed by a connecting portion between the inner conductor connecting portion and the circuit joint portion. The connection terminal of the coaxial resonator characterized in that. 2. An inner conductor connecting portion for connecting an inner conductor formed on an inner peripheral surface of a through hole of a coaxial resonator to the inner conductor electrically, and the inner conductor connecting portion. Of the inner conductor connecting portion and the support portion, the support portion projecting from one end of the inner conductor connecting portion and the circuit joint portion branched from the support portion for connecting to a circuit pattern on an electric circuit element or a wiring board. A connection terminal for a coaxial resonator, wherein at least one of a concave corner formed by a portion and a concave corner formed by a connecting portion between the support portion and the circuit joint portion is rounded. 3. An inner conductor connecting portion for connecting an inner conductor formed on the inner peripheral surface of the through hole of the coaxial resonator to the inner conductor, and one end of the inner conductor connecting portion. And a circuit joint portion that is connected to the electric circuit element or the circuit pattern on the wiring board and is soldered so as to round the corners of the recessed corner portion formed by the connecting portion between the inner conductor connecting portion and the circuit joint portion. The connection terminal of the coaxial resonator characterized in that. 4. An inner conductor connecting portion for electrically connecting to the inner conductor, the connecting terminal connecting to the inner conductor formed on the inner peripheral surface of the through hole of the coaxial resonator, and one end of the inner conductor connecting portion. And a circuit joint portion branched from the support portion for connecting to a circuit pattern on an electric circuit element or a wiring board, and a connecting portion between the inner conductor connecting portion and the support portion. A connection terminal for a coaxial resonator, wherein solder is welded so as to round at least one of the concave corner portion and the concave corner portion formed by the connecting portion between the support portion and the circuit joint portion. 5. A dielectric filter comprising a coaxial resonator having the connection terminal according to claim 1, 2, 3, or 4. 6. The dielectric filter according to claim 5, wherein a circuit joint portion of the connection terminal is soldered so that a portion where the circuit joint portion of the connection terminal is soldered to an electric circuit element or a circuit pattern on a wiring board cannot be angled. A dielectric filter characterized in that 7. The method of manufacturing a dielectric filter according to claim 5, wherein the circuit joint portion of the connection terminal is not soldered to a portion where the circuit joint portion of the connection terminal is soldered to an electric circuit element or a circuit pattern on a wiring board. A method for manufacturing a dielectric filter, characterized in that