JPH07154111A - Dielectric resonator and its characteristic setting method - Google Patents

Abstract

PURPOSE:To set and adjust the characteristic of the dielectric resonator without changing a metallic die or the like. CONSTITUTION:Part of a conductor layer 14 formed on an outer side face of a ferroelectric ceramic 10 is coated by a dielectric layer 26. Part of the dielectric layer 26 is coated by a conductor layer 28. Since a high frequency distributed capacitor is formed by the conductor layer 14, the dielectric layer 26 and the conductor layer 28, the characteristic of the dielectric resonator 18 is changed without changing a metallic die or the like to form the ferroelectric ceramic 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric resonator formed by ferroelectric ceramics and the like, and a method for setting its characteristics.

[0002]

2. Description of the Related Art In recent years, the field of wireless communication has made great progress mainly in cordless telephones, satellite communication and the like. Along with this, the frequency of wireless communication devices is increasing, and miniaturization is required. A so-called dielectric resonator is a component that contributes to higher frequencies and smaller sizes.

The dielectric resonator has a good impedance matching property, has a high Q, and since it uses a dielectric having a high dielectric constant, it can form a device smaller than a stripline. Have advantages. Due to these advantages, dielectric resonators are frequently used in oscillation circuits and resonance circuits in the band of several hundred MHz or higher. As a result, dielectric resonators are occupying an important position in the field of wireless communication.

Furthermore, dielectric resonators are being widely used in fields other than wireless communication. For example, an electrostatic sensor using a dielectric resonator and a cordless sensor mounted on an automobile or the like to reduce the wiring have been developed.
In each of these fields, simplification, miniaturization, weight reduction, etc. are required, and by using a dielectric resonator, these objects are suitably achieved.

As described above, the dielectric resonator is expanding its application in various fields such as communication, automobiles, measurement, and consumer equipment. Therefore, the dielectric resonator is required to be improved in its characteristics and to be manufactured in various types.

FIG. 22 shows an example of the shape of the dielectric resonator. In particular, the one shown in FIG. 22A is called a circular resonator, and the one shown in FIG. 22B is called a rectangular resonator.

The resonator shown in FIG. 22 has a structure in which conductor layers 12 and 14 are formed on the inner side surface and the outer side surface of a hollow cylindrical ferroelectric ceramic 10, respectively. The conductor layers 12 and 14 form a coaxial line using the ferroelectric ceramics 10 as a dielectric. When this core is configured as a quarter-wave resonator, the conductor layers 12 and 14 are short-circuited at the end surface of the ferroelectric ceramic 10 where the terminal 16 is not provided. A terminal 16 for inputting a high frequency signal is electrically connected to the conductor layer 12.

FIG. 23 shows a mounting method on a substrate. The resonator 18 shown in this figure is the rectangular resonator shown in FIG. 22B.
It can also be applied to the circular resonator shown in (a).

The conductor layer 1 formed on the outer surface of the resonator 18
4 is soldered to the ground conductor 22 on the substrate 20. Further, the terminal 16 is soldered to the signal conductor 24 on the substrate 20. By mounting the resonator 18 on the substrate 20 by such a method, the resonator 18 can be fixed on the substrate 20 and electrical connection can be secured. Board 20
Although not shown, components such as a transistor and a capacitor are mounted on the upper portion, and the resonator 18 constitutes a resonance circuit and the like together with these components.

[0010]

The basic characteristics of conventional dielectric resonators have been uniquely determined when their size and shape and materials are determined. That is, in order to change the characteristics even a little, it is necessary to renew the equipment such as the mold used for forming the ferroelectric ceramics, and a significant cost was incurred due to the specification change. .

The present invention has been made to solve the above problems, and the characteristics of the resonator can be improved by adding a simple structure to the dielectric resonator.
An object of the present invention is to enable setting and adjustment without changing the size and shape and the material, that is, without changing the mold or the like.

[0012]

In order to achieve such an object, a dielectric resonator according to the present invention has a dielectric core (for example, a ferroelectric ceramics core) provided with a conductor layer on its outer surface. Forming body), a coated dielectric layer formed so as to cover at least a part of the conductor layer, and a coated conductor layer formed so as to cover at least a part of the coated dielectric layer,
It is characterized by including.

Further, in the characteristic setting method according to the present invention, a coated dielectric layer is formed around an element having a conductor layer on its outer surface so as to cover at least a part of the conductor layer.
Further, a characteristic of the core is set and adjusted by forming a coated conductor layer so as to cover at least a part of the coated dielectric layer.

[0014]

In the present invention, the coating dielectric layer is formed around the core. The covering dielectric layer covers at least a part of the conductor layer provided on the outer surface of the core. Further, at least a part of the coated dielectric layer is coated with the coated conductor layer. The characteristics of the core obtained by using this coated conductor layer as the ground conductor are different from the characteristics of the conventional core. Therefore, in the present invention, the core is designed by the design of the coated dielectric layer or the coated conductor layer without changing the size and shape of the element or the material, that is, without renewing the equipment such as the mold for forming the core. It is possible to set and adjust the characteristics of.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. The same components as those of the conventional example shown in FIGS. 22 and 26 are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 1 shows the configuration of the first embodiment of the present invention. In particular, in FIG. 1A, the end face on the terminal 16 side is
FIG. 1B is a diagram showing a longitudinal side cross section of a portion (hereinafter referred to as a core) 18 corresponding to a conventional resonator.

As shown in this drawing, in this embodiment, a dielectric layer 26 is formed outside the conductor layer 14, and the dielectric layer 26 covers the conductor layer 14. Further, a conductor layer 28 is formed outside the dielectric layer 26, and the conductor layer 28 is covered with the dielectric layer 26.

As the dielectric layer 26, for example, various plastic films made of a dielectric material such as a single substance or a mixture of polyimide, polyester, acetate or a copolymer can be used. The thickness is, for example, 10
It may be about 50 μm. As the conductor layer 28, a good conductor such as steel, copper, aluminum, or gold can be used. If the thickness is 3 wavelengths or more, the function of the present invention is exhibited, but it may be, for example, about 35 to 100 μm. Further, in FIG. 1, the dielectric layer 26 and the conductor layer 28 are a pair, but a plurality of pairs of these may be provided.

FIG. 2 shows the configuration of the second embodiment of the present invention. In this embodiment, the dielectric layer 26 and the conductor layer 28 are formed around the conductor layer 14 so as to make a plurality of turns just like spirals.

FIG. 3 shows the configuration of the third embodiment of the present invention. In particular, in FIG. 3A, the end face on the terminal 16 side is
FIG. 3B shows a side cross section of the core 18 in the longitudinal direction. In this embodiment, a coated conductor wire is used as the conductor layer 28. That is, the covered conductor wire is wound around the dielectric layer 26, and thus the conductor layer 2 is formed.
8 are configured.

FIG. 4 shows the configuration of the fourth embodiment of the present invention. This figure is a top side view of the core 18. In this embodiment, the dielectric layer 26 or the conductor layer 28 is patterned.

FIG. 5 shows the configuration of the fifth embodiment of the present invention. This drawing is also an upper side view similar to FIG. 4, and the dielectric layer 26 or the conductor layer 28 is also patterned in this embodiment. However, the pattern is different from that of the fourth embodiment, and a comb-like pattern is formed.

FIG. 6 shows the configuration of the sixth embodiment of the present invention. This drawing shows the end face on the terminal 16 side.
In this embodiment, the dielectric layer 26 and the conductor layer 28 are not formed over the entire circumference of the conductor layer 14, but the dielectric layer 26 and the conductor layer 28 are laminated on one outer surface of the conductor layer 14. ing. The outermost conductor layer 28 of the conductor layers 28 is electrically connected to the connection member 30 by pressing contact or the like. The connecting member 30 has a “U” shape, and its tip is electrically connected to the ground conductor 22 on the substrate 20 by, for example, soldering.

FIG. 7 shows the configuration of the seventh embodiment of the present invention. In this embodiment as well, the same connecting member 30 as in the sixth embodiment is used, but its tip is not in direct contact with the ground conductor 22 or the like on the conductor 20. That is, the tip of the connecting member 30 floats from the substrate 20,
The ground conductor 22 is electromagnetically coupled.

FIG. 8 shows the configuration of the eighth embodiment of the present invention. This drawing shows the end face on the terminal 16 side.
In this embodiment, one of the two conductor layers 28 is
It has a "U" -shaped curved portion 28a and two "L" -shaped bridge portions 28b provided on both sides thereof. The core 18 is held by the bending portion 28a, and
Three side surfaces of the conductor layer 14 formed on the outer surface of each piece are covered with the curved portion 28a. Bridge part 28
b is soldered to, for example, the ground conductor 22 on the substrate 20. The dielectric layer 26 includes the curved portion 28 of the conductor layer 14.
One outer surface not covered by a and the bridging portion 28b
Part of it is covered. Another one on top of the dielectric layer 26
The individual conductor layers 28 are provided.

FIG. 9 shows the configuration of the ninth embodiment of the present invention. This embodiment is characterized in that the tip of the bridging portion 28b in the eighth embodiment is floated from the substrate 20 and is electromagnetically coupled to the ground conductor 22 like the tip of the connecting member 30 in the seventh embodiment. I am trying.

FIG. 10 shows the configuration of the tenth embodiment of the present invention. In this embodiment, the dielectric layer 26
Cover the three outer surfaces of the conductor layer 14. Conductor layer 28
Has the same shape as the connecting member 30 in the sixth or seventh embodiment. However, the conductor layer 28 is the sixth or the seventh.
The connection member 30 in the embodiment is arranged so as to be turned over, and the bottom of the conductor layer 28 is the ground conductor 22 on the substrate 20.
Is soldered to. Further, the tip of the conductor layer 28 extends left and right when viewed from the core 18. That is, the conductor layer 2
8 has two expansion parts 28c.

FIG. 11 shows the configuration of the eleventh embodiment of the present invention. This embodiment is a modification of the configuration of the tenth embodiment, in which a part 28d of the expanded portion 28c of the conductor layer 28 is bent in the direction opposite to the expanded direction of the expanded portion 28c, whereby the core 18 is strongly fixed as compared with the tenth embodiment. Along with this, the part 26a of the dielectric layer 26 is also expanded in the direction opposite to the expanding direction of the expanding portion 28c.

The feature common to these first to eleventh embodiments is, firstly, that the dielectric layer 26 is provided so as to cover at least a part of the conductor layer 14. Secondly, the dielectric layer 2
The conductor layer 28 is provided so as to cover at least a part of 6. In other words, the common feature is that a capacitor having the conductor layers 14 and 28 as electrodes and the dielectric layer 26 as a dielectric is formed.

This feature, that is, the capacitor formed on the outside of the conductor layer 14, has a core 18 as will be exemplified later.
The characteristics of is changed, and its Q is improved, for example. The principle of such an action has not been clarified at this stage, but it can be roughly inferred to be as follows.
That is, the conductor layer 14 is formed on the outer surface of the ferroelectric ceramics 10, and an eddy current is generated at the interface of the conductor layer 14 with the ferroelectric ceramics 10.
This eddy current is distributed according to the electric field distribution inside the ferroelectric ceramics 10. Therefore, when the dielectric layer 26 and the conductor layer 28 are provided as in the respective embodiments of the present invention and the conductor layer 14 is connected to the ground conductor 22 via a capacitor composed of these, the ferroelectric ceramics 10 is connected by the capacitor. It is considered that the electric field distribution in the inside is made uniform and the distribution of the eddy current in the conductor layer 14 becomes uniform. Due to this homogenization, the conductor layer 1 of the characteristics of the core 18
It is considered that the resistance component depending on the eddy current inside the No. 4 changes.

The capacitor formed of the conductor layer 14, the dielectric layer 26 and the conductor layer 28 is a capacitor in the high frequency sense, that is, a distributed capacitance. Therefore, the characteristic changing action in each embodiment of the present invention is, for example, 500M.
It is thought to occur at high frequencies above Hz. Further, since this capacitor has a distributed capacitance, the above-mentioned characteristic change action occurs even if the conductor layer 14 and the conductor layer 28 are in contact with each other at a low frequency as in the eighth or ninth embodiment. .
Furthermore, at such a high frequency, the electromagnetic field coupling as shown in the seventh or ninth embodiment is also possible.

In addition, in the tenth and eleventh embodiments, the conductor layer 28 also functions as a member for holding and fixing the core 18. That is, the core 18 is sandwiched and fixed by the conductor layer 28, and contact with the ground conductor 22 is maintained via the core 28. Therefore, only the conductor layer 28 is sufficient as the member to be soldered to the board 20, and the core 18 is mounted on the board 2 without using a soldering iron having a large output.
A simple method such as mounting on top of 0, eyelet stop, etc. becomes possible. In addition, if the structure of the eleventh embodiment is used,
The holding strength of the core 18 by the conductor layer 28 can be further increased.

12 to 24 show the method of characteristic measurement performed by the inventor of the present invention and the result thereof. In particular, FIG. 12 (a) shows the front surface of the measuring jig used by the inventor, FIG. 12 (b) shows the side surface, FIGS. 13 to 22 show the characteristic measurement results of the respective examples, and FIG. Shows the results of measurement reproducibility confirmation.

As shown in FIG. 12, in the jig 32 used by the inventor, the conductor 36 of the coaxial cable 34 is connected to the terminal 16
Alternatively, the phosphor bronze 3 is pressed against the signal conductor 24 while being pressed.
8 is a structure in which a spring electrode composed of 8 and a foil 40 is brought into spring contact with the conductor layer 28 of the core 18. Also, this jig 3
2 has a cover 42 surrounding the measurement site. The cover 42 is formed of, for example, a copper plate having a thickness of 0.8 mm, and the coaxial cable 34 penetrates the cover 42. The phosphor bronze 38 and the foil 40 are spot-welded to the inside of the cover 42 and then soldered.
4 is soldered at its penetrating portion. Radio frequency (RF) signals for measurement are supplied via the coaxial cable 34.

FIGS. 13 to 21 are frequency vs. attenuation amount data obtained using the jig 32 shown in FIG.
Frequency (MHz, linear) on the horizontal axis, attenuation (dB) on the vertical axis
And the thickness of the dielectric layer 26 is 50 μm. Also,
The sample for measurement is a sample using a copper plate of 50 μm as the conductor layer 28. In each figure, sample 1 and sample 2
Note that although the same reference numerals are used and the same sample number appears in different figures, the same sample number appearing in different figures generally does not indicate the same sample.

First, when the structure of the first embodiment is adopted and polyimide is used as the material of the dielectric layer 26, the measurement results as shown in FIGS. 13 and 14 are obtained. Of these figures, FIG. 13 shows the case where the dielectric layer 26 is one layer, and FIG. 14 shows the case where the dielectric layer 26 is five layers. As is clear from these figures, when the dielectric layer 26 is made of polyimide in the configuration of the first embodiment, the Q at the resonance point is better than that of the core alone. Further, when the number of layers of the dielectric layer 26 is 5, the Q is further improved as compared with the case where the number of layers is 1.

FIGS. 15 and 16 show the characteristic measurement results when acetate is used as the dielectric layer 26. In particular, FIG. 15 shows the case where the number of dielectric layers 26 is 5 in the structure of the first embodiment, and FIG. 16 is the number of dielectric layers 26 is 1 in the structure of the eighth embodiment. This is the case. As shown in these figures, in both the first embodiment and the eighth embodiment, the Q at the resonance point is better than that of the core alone. Similar results are obtained when Teflon (trademark), mylar, blend tape, polyethylene terephthalate (PET), or the like is used as the dielectric layer 26. FIG. 17 shows the characteristic measurement results when the number of dielectric layers 26 is 5 and Teflon is used as the material thereof in the first embodiment. FIG. 18 shows the characteristics when the dielectric layer 26 is one layer and the material is Mylar in the first embodiment. Further, FIGS. 19 and 20 show the characteristic measurement results when the dielectric layer 26 is a blend tape in the first embodiment. The number of dielectric layers 26 in FIG. 19 is one layer, and FIG. The number of layers in is 5
It is a layer. FIG. 21 shows that the dielectric layer 26 in the second embodiment is a pet (Panak Co., trade name: GS-3).
8) is the result of characteristic measurement when it is wound twice, and in this case, the thickness of the dielectric layer 26 is 35 μm.

As described above, according to the characteristic measurement result of the inventor, it can be seen that the characteristic change of the core 18 described above obviously occurs.

Although the above description has been made with respect to the case where a rectangular core is used as the core 18, the same action and effect also occur when the dielectric layer 26 and the conductor layer 28 are provided in the round core. . Further, although the above description is for the quarter-wave resonator, the present invention can be applied to a half-wave resonator and the like.

[0040]

As described above, according to the present invention,
Since the covering dielectric layer is provided so as to cover at least a part of the conductor layer provided on the outer surface of the core, and the covering layer is formed so as to cover at least a part of the covering dielectric layer, the dielectric The characteristics of the body resonator can be modified by the design of the coated dielectric layer and the coated conductor layer without recreating the equipment such as the mold for forming the core. Will be easier.
As a result, the manufacturing cost of the dielectric resonator can be reduced and its application can be further expanded.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a first embodiment of the present invention, FIG. 1 (a) is an end view on a terminal side, and FIG. 1 (b) is a side sectional view in a core longitudinal direction.

FIG. 2 is an end view on the terminal side showing the configuration of a second embodiment of the present invention.

3A and 3B are diagrams showing a configuration of a third embodiment of the present invention, FIG. 3A is an end view on the terminal side, and FIG. 3B is a side sectional view in the core longitudinal direction.

FIG. 4 is an upper side view showing the configuration of the fourth exemplary embodiment of the present invention.

FIG. 5 is an upper side view showing the configuration of the fifth embodiment of the present invention.

FIG. 6 is an end view on the terminal side showing the configuration of a sixth embodiment of the present invention.

FIG. 7 is an end view on the terminal side showing the configuration of a seventh embodiment of the present invention.

FIG. 8 is an end view on the terminal side showing the configuration of an eighth embodiment of the present invention.

FIG. 9 is an end view on the terminal side showing the configuration of a ninth embodiment of the present invention.

FIG. 10 is a perspective view showing the configuration of a tenth embodiment of the present invention.

FIG. 11 is a perspective view showing the structure of an eleventh embodiment of the present invention.

12A and 12B are diagrams showing a configuration of a jig used by the inventor for characteristic measurement. FIG. 1A is a front view, and FIG. 12B is a side view (a sectional view only inside a cover).

FIG. 13 is a diagram showing a characteristic measurement result by the inventor,
FIG. 5 is a characteristic diagram in the case where one dielectric layer is used and its material is polyimide in the first embodiment.

FIG. 14 is a diagram showing a characteristic measurement result by the inventor,
FIG. 6 is a characteristic diagram in the case where five dielectric layers are used and a material thereof is polyimide in the first embodiment.

FIG. 15 is a diagram showing a characteristic measurement result by the inventor,
FIG. 5 is a characteristic diagram when five dielectric layers are used and the material thereof is acetate in the first embodiment.

FIG. 16 is a diagram showing a characteristic measurement result by the inventor,
FIG. 20 is a characteristic diagram in the case where one dielectric layer is used and the material thereof is acetate in the eighth embodiment.

FIG. 17 is a diagram showing a characteristic measurement result by the inventor,
FIG. 6 is a characteristic diagram when five dielectric layers are used and the material is Teflon in the first embodiment.

FIG. 18 is a diagram showing a characteristic measurement result by the inventor,
FIG. 6 is a characteristic diagram when one dielectric layer is used and the material is Mylar in the first embodiment.

FIG. 19 is a diagram showing a characteristic measurement result by the inventor,
FIG. 6 is a characteristic diagram in the case where one dielectric layer is used and a material thereof is a blend tape in the first embodiment.

FIG. 20 is a diagram showing a characteristic measurement result by the inventor,
FIG. 6 is a characteristic diagram in the case where five dielectric layers are used and a material thereof is a blend tape in the first embodiment.

FIG. 21 is a diagram showing a characteristic measurement result by the inventor,
FIG. 9 is a characteristic diagram when the dielectric layer is wound twice and the material is polyethylene terephthalate in the second example.

22 is a view showing an example of the shape of a conventional dielectric resonator, FIG. 22 (a) shows a round core, and FIG. 22 (b).
FIG. 3 is a diagram showing a rectangular core, respectively.

FIG. 23 is a perspective view showing a method for mounting a conventional dielectric resonator on a substrate.

[Explanation of symbols]

 10 Ferroelectric Ceramics 12, 14, 28 Conductor Layer 16 Terminal 18 Core 20 Substrate 22 Grounding Conductor 24 Signal Conductor 26 Dielectric Layer

Claims (2)

[Claims] 1. A dielectric core having a conductor layer on its outer surface, a coated dielectric layer formed to cover at least a part of the conductor layer, and at least a portion of the covered dielectric layer. And a coated conductor layer formed so as to have a dielectric resonator. 2. A coated dielectric layer is formed so as to cover at least a part of the conductor layer around a core of a dielectric having a conductor layer provided on the outer surface thereof, and at least a part of the coated dielectric layer. A method for setting the characteristics of a dielectric resonator, wherein the characteristics of the dielectric resonator are set and adjusted by forming a coated conductor layer to cover the.