JPH08335806A - Band pass filter - Google Patents

Abstract

PURPOSE: To adjust the frequency of a band pass filter even after it is mounted. CONSTITUTION: The dielectric coaxial resonators 8, 9 and 10 are mounted on a substrate 1 in parallel to each other. At the same time, the input/output electrodes 14 are placed on one of both sides of surfaces of resonators 8 to 10 touching the substrate 1, together with the input/output electrodes 15 placed on the other side of the surfaces of these resonators and the frequency electrodes 13 placed between the electrodes 14 and 15 respectively. Then the electrode 15 of the resonator 8 is electrically connected to the electrode 14 of the resonator 9. Furthermore, these electrodes 13 to 15 of resonators 8 to 10 are facing to an opening part 16 of the substrate 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bandpass filter used in mobile communication equipment and the like.

[0002]

2. Description of the Related Art In a conventional bandpass filter, at least two coaxial type dielectric resonators are mounted on a substrate having electrodes, and one end of a terminal is inserted into an inner conductor of the dielectric resonator. , The other end of this terminal was connected to an electrode on this substrate. The electrodes are used to connect and mount the coupling capacitors and the capacitors of the dielectric resonators.

[0003]

In the above configuration, when the frequency is adjusted as the bandpass filter, the coupling or frequency adjusting capacitors are appropriately replaced and mounted. Such a capacitor is replaced. The mounting work was very time-consuming.

Therefore, the present invention has an object to provide a band-pass filter which can easily perform such frequency adjustment.

[0005]

In order to achieve this object, the present invention comprises at least two coaxial type dielectric resonators mounted in parallel on a substrate, wherein the two dielectric resonators are provided. The input electrode on one side, the output electrode on the other side, the frequency adjustment electrode between the input and output electrodes, and the output electrode of one dielectric resonator Is electrically connected to the input electrode of the dielectric resonator, and the input / output electrodes and the frequency adjusting electrode of these two dielectric resonators are made to face the opening provided in the substrate.

[0006]

With the above structure, the frequency adjustment is appropriately performed according to the amount of the at least one of the input / output electrode or the frequency adjustment electrode to be scraped from the back side of the substrate through the opening provided in the substrate. Can be done, and the workability is extremely easy.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 1 is a substrate formed of a material having a low dielectric constant, and as shown in FIG. 7, electrodes 2, 3, 4, 5, 6, 7 are provided on the surface side thereof. . Further, three dielectric coaxial resonators 8, 9 and 10 are mounted in parallel on the substrate 1. These dielectric coaxial resonators 8 to
As shown in FIG. 6, 10 has a prismatic shape, and a through hole 11 is provided in the central portion thereof. An electrode 12 is provided in the through hole 11 and on the outer peripheral surface and the lower surface in FIG. In addition, these dielectric coaxial resonators 8 to 10
In the mounting surface portion of the substrate 1 on the open end side, the wide portion 13
Frequency adjustment electrode 1 in which the width a is 13a
3 are provided, and island-shaped input / output electrodes 14 and 15 extending to the side surfaces are provided on both sides of the small width portion 13b.

These dielectric coaxial resonators 8 to 10 are shown in FIG.
1 is mounted on the substrate 1 shown in FIG. By this mounting, the wide portion 13a of the frequency adjusting electrode 13 of the dielectric coaxial resonator 8 is soldered to the electrode 4 of the substrate 1, and similarly, the wide portion 13a of the frequency adjusting electrode 13 of the dielectric coaxial resonators 9 and 10 is soldered. Is also soldered to the electrode 4 of the substrate 1 and electrically connected. And the dielectric coaxial resonator 8
10 to 10 of the island-shaped input / output electrodes 14 and 15 are soldered to the input / output electrodes 14 and 15 of the dielectric coaxial resonator which are arranged in parallel, and the island-shaped input / output electrodes 14 which are not arranged in parallel to each other. Is soldered to the electrode 2 on the substrate 1, and the island-shaped input / output electrode 15 on the other side which is not in parallel is soldered to the electrode 3 on the substrate 1 so as to be electrically connected.

On the substrate 1, the fixing electrodes 5, 5 are also provided.
6 and 7 are provided side by side, and the electrodes are provided with a dielectric coaxial resonator 8 on the electrode 5, a dielectric coaxial resonator 9 on the electrode 6, and a dielectric coaxial resonator 10 on the electrode 7. Each is fixed.

In this embodiment, as shown in FIG. 7, an opening 16 is provided in the center of the substrate 1, and the opening 16 is provided.
As shown in FIG. 3, the dielectric coaxial resonators 8 to 1
0 input / output electrodes 14 and 15 and frequency adjustment electrode 1
The width details 13b of 3 can be seen. Therefore, if the input / output electrodes 14 and 15 on the side where the dielectric coaxial resonators 8 to 10 are not in parallel contact with each other are cut through the opening 16, the capacitance values of the capacitors 17 and 20 shown in FIG. 4 can be changed. be able to. Then, by removing the island-shaped input / output electrodes 14 and 15 on the side where the dielectric coaxial resonators 8 to 10 are in parallel, the capacitance values of the capacitors 18 and 19 shown in FIG. 4 can be varied. Further, by removing the width detail 13b of the frequency adjustment electrode 13 of the dielectric coaxial resonators 8 to 10, the capacitance values of the capacitors 21, 22, and 23 shown in FIG. 4 can be changed. As a result, a bandpass filter as shown in FIG. 4 is constructed.

In the bandpass filter shown in FIG. 4, 21, 22, and 23 are formed between the width detail 13b of the frequency adjusting electrode 13 of the dielectric coaxial resonators 8 to 10 and the electrode 12 in the through hole 11. This is the capacitance of the capacitor, and the larger the area of the width detail 13b cut from the rear surface side of the substrate 1 through the opening 16, the smaller the capacitance value becomes.
As a result, the pass band of the band pass filter characteristic rises to the high band.

In the bandpass filter shown in FIG. 4, 18 and 19 are formed between the island-shaped input / output electrodes 14 and 15 of the dielectric coaxial resonators 8 to 10 and the electrode 12 in the through hole 11. This is the capacitance of the capacitor, and by connecting the dielectric coaxial resonators 8 to 10 in parallel, the resonators are coupled by the capacitors 18 and 19, and the capacitor not in parallel is the input / output capacitor 17. , 20
Becomes

The coupling capacitors 18 and 19 are mounted on the substrate 1.
The larger the area to be shaved from the back surface side through the opening 16 is, the smaller the capacitance value is. As a result, the degree of coupling formed on the low frequency side of the filter pass characteristic is weakened. Similarly, the larger the area of the input / output capacitors 17 and 20 to be cut from the back surface of the substrate 1 through the opening 16 is, the smaller the capacitance value is, and as a result, the filter pass characteristic can be adjusted.

[0014]

As described above, the present invention is provided with at least two coaxial type dielectric resonators mounted in parallel on the substrate, and the surfaces of the two dielectric resonators that are in contact with the substrate. Each of them has an input electrode on one side, an output electrode on the other side, and a frequency adjustment electrode between the input and output electrodes, and the output electrode of one dielectric resonator and the input of the other dielectric resonator. Since the input / output electrodes and the frequency adjusting electrodes of these two dielectric resonators are electrically connected to the electrodes and face the opening provided in the substrate, the frequency adjustment is performed in the opening provided in the substrate. At least one of the input / output electrode or the frequency adjustment electrode from the back side of the substrate via
The workability can be extremely simplified because the work can be performed appropriately according to the amount of scraping off.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of a bandpass filter of the present invention.

FIG. 2 is a top view of the same.

[Figure 3] Rear view of the same

FIG. 4 is an electrical equivalent circuit diagram of the same.

FIG. 5 is an exploded perspective view of the same.

FIG. 6 is a perspective view of the dielectric resonator.

FIG. 7 is a perspective view of the board.

[Explanation of symbols]

 1 Substrate 2 Electrode 3 Electrode 4 Electrode 8 Dielectric Coaxial Resonator 9 Dielectric Coaxial Resonator 10 Dielectric Coaxial Resonator 11 Through Hole 12 Electrode 13 Frequency Adjustment Electrode 13a Wide Part 13b Width Detail 14 Input / Output Electrode 15 Input / Output Electrode 16 opening

Claims (3)

[Claims] 1. At least two coaxial type dielectric resonators mounted side by side on a substrate are provided, and the surfaces of the two dielectric resonators in contact with the substrate are respectively input to one side thereof. Electrodes, output electrodes on the other side, and frequency adjustment electrodes between the input and output electrodes, and electrically connect the output electrode of one dielectric resonator and the input electrode of the other dielectric resonator. , A bandpass filter in which the input / output electrodes and the frequency adjusting electrodes of these dielectric resonators are made to face an opening provided in a substrate. 2. The frequency adjustment electrode of at least one of the two dielectric resonators has a linear width detail facing the inner conductor of the dielectric resonator, and extends laterally at one end of this width detail. The bandpass filter according to claim 1, comprising a wide portion. 3. The bandpass filter according to claim 1, wherein the opening is smaller than at least two dielectric resonators arranged in parallel.