JPH09246808A - Dielectric block and dielectric filter using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the dielectric block with ease of design developed early by forming two non-throughholes coaxially from one side to a center of the block made of a dielectric material from the other side to the center to the block. SOLUTION: The dielectric block 1 is made of a dielectric material and formed to be nearly a prism and has a 1st end face 13 and a 2nd end face 14, and a non-throughhole 15 is formed from the 1st end face 13 to the center and from the 2nd end face 14 to the center respectively. The two non- throughholes are formed coaxially. Thus, no undesired capacitive coupling is caused and the propagation direction of an electromagnetic wave is straightforward from the 1st 3nd face 13 to the 2nd end face 14 via two resonators, the deterioration in the characteristic is less than that of a conventional block. Thus the dielectric block 1 mounted on the surface without leakage of an electric field with ease of design and development and also a dielectric filter using the dielectric block are realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric filter used in radio communication in a high frequency band and a dielectric block for the dielectric filter, which is a component thereof, and more specifically, a dielectric filter with lower loss. And its dielectric block.

[0002]

2. Description of the Related Art A conventional technique will be described with reference to the drawings. Here, in order to realize a low-loss filter, λ / 2
FIG. 6 shows an example in which a band-pass filter using two resonators is realized as a surface-mounted dielectric filter. Two
Two λ / 2 coaxial dielectric resonators 61 are connected on a mounting substrate 62, and an electric circuit element 64 connected on a circuit pattern 63 formed on the mounting substrate 62 is connected to the resonator 61 and a bonding terminal 65. Thus, a bandpass filter is formed between the input / output terminals 66.

Such a bandpass filter is often mounted on a mobile radio device and is required to be small and lightweight and low in price, but the number of parts is large, the process is complicated, and the members to be used are large. Requires high quality such as heat resistance, temperature characteristics, and dielectric characteristics, and is expensive, and it is difficult to realize downsizing, weight reduction, and cost reduction.

Therefore, recently, a bandpass filter may be realized by a single dielectric block without using a mounting substrate or a circuit element. An example thereof is shown in FIG. In this dielectric filter 7, two through holes 72 are formed in a dielectric block 71, and the inner surface of the through hole 72 and the outer peripheral surface of the dielectric block 71 are covered with a conductor 73. First end face 7
There is no conductor on both 4 and the second end surface 75, and this is an open end, the conductor 73 on the inner surface of the through hole 72 is the inner conductor, and the conductor 73 on the outer peripheral surface of the dielectric block 71 is the outer conductor. It can be regarded as a / 2 resonator. Further, since the input / output terminal 76 is capacitively coupled to the in-resonator conductor via the dielectric and the two in-resonator conductors are also capacitively coupled to each other, the input / output terminal 76 functions as a bandpass filter between the input / output terminals.

[0005]

In the case of the dielectric filter formed on the substrate shown in FIG. 6, a bandpass filter in which the dielectric resonator, the mounting substrate, the circuit coupling element, and the joining terminal are connected by soldering or the like is used. Although it is configured, the number of parts is large and the manufacturing process is complicated. Moreover, when an attempt is made to realize a surface mount type bandpass filter, the members used must be high in heat resistance, temperature characteristics, dielectric characteristics, frequency characteristics, etc., and are expensive. Therefore, it is difficult to realize a small size, a light weight, and a low price.

In the case of the dielectric filter using the dielectric block shown in FIG. 7, compared to the dielectric filter shown in FIG. 6, the dielectric block alone has a small number of parts and the manufacturing process is simple and the cost can be reduced. Although it is configured, one dielectric block composes all the circuits, so that the structural design of the dielectric block is complicated.

In the case of the dielectric filter shown in FIG. 6, since the element structure of the equivalent circuit corresponds to the element actually used as it is, it can be easily calculated by circuit simulation. However, in the case of the dielectric filter shown in FIG. 7, since the input / output terminals and inner conductors necessary for the circuit configuration are close to each other and are capacitively coupled to each other,
There are many capacitive couplings even in parts that should not be needed.
For this reason, it becomes a complicated circuit configuration that is difficult to represent with an equivalent circuit, calculation by simulation is not easy, and the characteristics deteriorate due to unnecessary capacitive coupling.

Further, for example, when it is desired to change the circuit constant at one place, in the case of the dielectric filter shown in FIG. 6, it suffices to change one circuit element value corresponding thereto, but the dielectric filter shown in FIG. In this case, if one attempt is made to change the predetermined number, the characteristics of the entire circuit are greatly changed by affecting not only the portion to be changed due to the influence of capacitive coupling.
Therefore, it is difficult to design and develop when designing the structure of the dielectric block.

In order to overcome the above-mentioned drawbacks, the present invention satisfies the requirements for downsizing, weight reduction and cost reduction of the dielectric filter, and the design is easier and the early development is possible as compared with the conventional dielectric filter. It is an object to provide a dielectric block having

[0010]

A dielectric block of the present invention is made of a dielectric material and has one surface and another surface which is an opposite surface of the one surface. It is characterized in that the two non-through holes are formed so that their axes are coaxial.

Further, the dielectric block of the present invention is made of a dielectric material, and two block division bodies having through holes from one surface to the other surface opposite to the one surface are separated by a dielectric plate. It is characterized in that the two through-holes are attached so that the axes thereof are coaxial.

Further, a dielectric filter of the present invention is a dielectric filter using the above dielectric block, wherein the dielectric block is provided with input / output electrodes, and both end surfaces in the axial direction of the dielectric block, And the entire surface including the inner surface of the hole is covered with a conductor except the area around the input / output electrode.

Further, a dielectric filter of the present invention is a dielectric filter using the above-mentioned dielectric block, wherein the dielectric block is provided with input / output electrodes, and the both end surfaces in the axial direction of the dielectric block are provided. The entire surface including the inner surface of the hole is covered with a conductor except for a region near the opening and a region around the input / output electrode.

Further, the dielectric filter of the present invention is a dielectric filter using the above dielectric block, wherein the dielectric block is provided with an input / output electrode, except for a region around the input / output electrode. The entire surface including the inner surface of the hole is covered with a conductor.

[0015]

1 to 5 show an embodiment of the present invention.

FIG. 1 is a perspective view of a dielectric block according to the first embodiment of the present invention. Referring to FIG. 1, this dielectric block 1 is made of a dielectric material and has a substantially prismatic shape, and has a first end face 13 and a second end face which is an opposing face of the first end face 13.
End face 14 of the non-through hole 15 is formed from the first end face 13 and the second end face 14 toward the center direction. The axes of the two non-through holes 15 are coaxial.

FIG. 2 is a perspective view of a dielectric block according to the second embodiment of the present invention. Referring to FIG. 2, each of the dielectric blocks 1 is made of a dielectric material and has a through hole 1
Two substantially cubic block division bodies 10 each having
The two through-holes 16 are attached to each other via the dielectric plate 11 so that the axes of the through-holes 16 are coaxial with each other.

The dielectric block 1 shown in FIGS. 1 and 2.
Is suitable for a surface mount type dielectric filter which is used in a mobile communication radio such as a mobile phone or a digital cordless phone and which is composed of a single dielectric block.

FIG. 3 is a perspective view of a dielectric filter according to a third embodiment of the present invention. With reference to FIG. 3, this dielectric filter 3 is obtained by covering the inner surface of the non-through hole 15 and the outer peripheral surface of the block with a conductor 21 in the dielectric block 1 shown in FIG.
An input terminal 22 is provided from the first end face 13 of the dielectric block 1 to one side face adjacent thereto, and an output terminal 23 is provided from the second end face 14 to one side face adjacent thereto. Is. At this time, the conductor 21 that covers the inner surface of the non-through hole 15 becomes the resonator inner conductor 24, and the conductor 21 that covers the outer peripheral surface of the dielectric block 1 becomes the resonator outer conductor 25.

Further, by opening the respective end faces 13 and 14 and setting the length of the in-resonator conductor 24 to λ / 2, the electric field at both ends of each in-resonator conductor 24 becomes maximum at the resonance frequency, It has the same characteristics as the λ / 2 resonator. Then, the in-resonator conductor 24 is formed from both end faces 13 and 14 of the dielectric block 1 toward the center thereof.
Are capacitively coupled to each other via the dielectric near the center of the dielectric block 1, and similarly, the input / output terminals 22 and 23 are also capacitively coupled to the in-resonator conductor 24 to form a bandpass filter between the input / output terminals 22 and 23. Function.

This configuration can be considered in the same manner as the configuration in which two λ / 2 resonators are connected via a dielectric, and an input / output terminal formed near the end face of one λ / 2 resonator and the other. The capacitive connection with the λ / 2 intracavity conductor is negligibly small. Further, the two intra-cavity conductors are arranged at parallel positions in the conventional example shown in FIG. 7, but capacitive coupling is required because they are arranged on the same axis in the dielectric block according to the present invention. That is, only that portion, that is, the vicinity of the center of the dielectric block is capacitively coupled.

For this reason, the input / output terminals and inner conductors necessary for the circuit configuration can be treated independently.
Adjustments for each element are facilitated, circuit simulation with an equivalent circuit is also possible, and design can be facilitated. Also,
Since there is no unnecessary capacitive coupling and the direction of electromagnetic wave propagation is linear from the first end face through the two resonators to the second end face, a dielectric filter with less deterioration in characteristics than before is realized. It becomes possible to do.

Of course, the dielectric filter 3 of this embodiment is
It is also possible to use the dielectric block 1 shown in FIG.

FIG. 4 is a perspective view of a dielectric filter according to the fourth embodiment of the present invention. With reference to FIG. 4, this dielectric filter 3 has a structure in which the dielectric filter 3 shown in FIG.
It is covered with the conductor 21 except for 2, 23 and its periphery. By doing so, it is possible to prevent the electric field from leaking from the open end, and improve the reliability when the device is mounted on a wireless device as a device.

Of course, the dielectric filter 3 of this embodiment is
It is also possible to use the dielectric block 1 shown in FIG.

FIG. 5 is a perspective view of a dielectric filter according to the fifth embodiment of the present invention. This dielectric filter 3 is
Input / output terminals 22, 2 are provided on the dielectric block 1 shown in FIG.
The conductor 21 is applied to the whole except for 3 and its periphery. Both the first end surface 13 and the second end surface 14 are short-circuited ends, and the input / output terminals 22 and 23 are formed near the center of the outer peripheral surface. In this configuration, the resonator portion is λ / 4
It can be regarded as a resonator, and a dielectric filter having a small shape can be realized.

Of course, the dielectric filter 3 of this embodiment is
It is also possible to use the dielectric block 1 shown in FIG.

By forming at least a part of the input / output terminals 22 and 23 of the dielectric filter 3 shown in FIGS. 3 to 5 on the same outer peripheral surface, surface mounting becomes possible, and the dielectric block alone is surface mounted. Type dielectric filter.

[0029]

As described above, according to the present invention, unnecessary capacitive coupling is less likely to occur, deterioration of characteristics is reduced, design development is easy, and there is no electric field leakage, and a surface mountable dielectric filter is provided. Can be realized.

[Brief description of drawings]

FIG. 1 is a perspective view of a dielectric block according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a dielectric block according to a second embodiment of the present invention.

FIG. 3 is a perspective view of a dielectric filter according to a third embodiment of the present invention.

FIG. 4 is a perspective view of a dielectric filter according to a fourth embodiment of the present invention.

FIG. 5 is a perspective view of a dielectric filter according to a fifth embodiment of the present invention.

FIG. 6 is a perspective view of a conventional board-mounted dielectric filter.

FIG. 7 is a perspective view of a conventional dielectric filter composed of a single dielectric block.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dielectric block 3 Dielectric filter 10 Block division body 11 Dielectric plate 13 1st end surface 14 2nd end surface 15 Non-through hole 16 Through hole 21 Conductor 22 Input terminal 23 Output terminal 24 In-resonator conductor 25 Outside resonator conductor

Claims (5)

[Claims] 1. A dielectric material having one surface and another surface which is an opposite surface of the one surface, and two non-through holes having their axes coaxial with each other from the one surface and the other surface toward the center. A dielectric block characterized by being formed as follows. 2. Two block division bodies made of a dielectric material and having a through hole extending from one surface to the other surface which is an opposite surface of the one surface are coaxial with each other through the dielectric plate. A dielectric block characterized by being bonded so that 3. A dielectric filter using the dielectric block according to claim 1 or 2, wherein the dielectric block is provided with input / output electrodes, and both ends of the dielectric block in the axial direction are provided. A dielectric filter, characterized in that the entire surface including the inner surface of the hole is covered with a conductor except for the surface and the area around the input / output electrode. 4. A dielectric filter using the dielectric block according to claim 1, wherein the dielectric block is provided with input / output electrodes, and both ends of the dielectric block in the axial direction are provided. A dielectric filter, characterized in that the entire surface including the inner surface of the hole is covered with a conductor except for the area near the opening of the surface and the area around the input / output electrode. 5. A dielectric filter using the dielectric block according to claim 1 or 2, wherein an input / output electrode is provided in the dielectric block, and a region around the input / output electrode is provided. Except for the inner surface of the hole, the entire surface of the hole is covered with a conductor.