JP2002171102A - Dielectric waveguide resonator and filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dielectric waveguide resonator and a filter which are easily designed and manufactured independently of the frequencies of signals. SOLUTION: A cutoff waveguide (d) is provided to a part of a dielectric waveguide 1 which is formed in a dielectric board and provided with an H plane composed of conductor layers 1a and 1b, and an E plane composed of a group of conductor vias 1c arranged at an internal below half the wavelength of signals or a group of conductor vias 1c and a conductor belt 1d. Dielectric vias 5 which are formed of dielectric which has higher dielectric constant than that forms the dielectric waveguide are provided in the cutoff waveguide d.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric waveguide resonator and a filter mainly used for microwaves and millimeter waves, and more particularly to a dielectric waveguide resonator and a filter which can be built in a dielectric multilayer substrate.

[0002]

2. Description of the Related Art FIG. 8 shows an example of a conventional waveguide filter. 31 is a waveguide, 32 is an input port, 33 is an output port, and 35, 36 and 37 are resonators. In this waveguide filter, a constricted portion 34 is provided in a part of the waveguide, and waveguide resonators 35, 36, and 37 are provided therebetween.
This is a stage filter formed. Each resonator 35, 3
By adjusting the characteristics of 6, 37 and the number of resonator stages, the characteristics of the whole filter are controlled.

[0003] The waveguide filter having such a structure has a structure that is very difficult to form with a waveguide in which a normal waveguide wall is entirely made of a metal plate. So, USP53829
No. 31 proposes that this structure be provided in a dielectric waveguide formed by laminating dielectric sheets. As one of the above, as shown in FIG. 9, conductor vias 38 are arranged in a dielectric substrate at intervals of less than 1/2 of a signal wavelength, and this is set as an E plane. Resonator 3
9 is formed to form a filter structure as a whole. This structure is advantageous in that it can be manufactured by applying a conventional lamination technique.

[0004]

However, the dielectric waveguide filter shown in FIG. 9 has the following problems. First, there are restrictions on the diameter of conductor vias and their pitch in manufacturing. For example, when the via diameter is φ0.2 mm,
It is desired that the via pitch is 0.5 mm or more. This is because if the via pitch is too narrow, cracks may occur between the vias, resulting in poor reliability.

[0005] Second, the conductive via 38 is formed of the dielectric waveguide E.
Since it forms a surface, in principle, it must be set at an interval of at most less than half the signal wavelength. Therefore, as shown in FIG. 9A, when the frequency to be used is low, that is, when the signal wavelength is long, the resonator 39 is used.
Is large, there is no problem even if the via pitch is 0.5 mm or more, since the resonator 39 and the dielectric waveguide can be formed with a sufficient number of vias. However, as shown in FIG. 9B, when the frequency used increases, the
Becomes short, the number of conductor vias 38 that can be arranged on the side surrounding the resonator 39 becomes several. In some cases, they cannot be arranged within the above-mentioned via pitch limitation. Further, since the equivalent waveguide size varies depending on the via pitch, it is very difficult to design the dielectric waveguide formed by the conductor via 38.

Accordingly, it is an object of the present invention to provide a resonator or a filter which can be easily designed and manufactured regardless of the level of a signal frequency.

[0007]

The present inventor has studied the above problem, and as a result, as shown in FIG. 9, a resonator is formed by surrounding the conductor via with a size matched to the frequency by a conductor via. Rather, a dielectric via in which conductive vias are arranged at equal intervals in two rows with a predetermined width, and a large number of dielectrics higher than the dielectric constant of the dielectric substrate are embedded between the two rows of conductive vias The inventors have found that a resonator can be formed by forming a group, and a dielectric waveguide filter can be formed by connecting the resonators, and the present invention has been accomplished.

That is, a dielectric waveguide resonator according to the present invention is formed in a dielectric substrate, wherein the H plane is formed of a conductor layer, and the E plane is arranged at an interval of less than half the signal wavelength. A cut-off waveguide is formed in a part of the dielectric waveguide composed of the via group, and a dielectric having a higher dielectric constant than the dielectric forming the dielectric waveguide is formed in the cut-off waveguide. A dielectric via is formed.

In the above dielectric waveguide resonator, a conductor band for electrically connecting adjacent conductor vias is formed in the E plane formed by the group of conductor vias, thereby forming a dielectric waveguide. Since the tube can be formed with several layers and can be made thick, the loss can be reduced.

Further, by providing a plurality of dielectric vias, the resonance frequency can be adjusted, and the resonance characteristics can be adjusted by changing the arrangement of the dielectric vias. In particular, when the dielectric vias are arranged on the central axis of the cut-off waveguide and / or a plurality of dielectric vias are arranged at symmetric positions with respect to the central axis, the dielectric via has an effect of increasing the effective dielectric constant. .

The dielectric forming the dielectric waveguide is a low-temperature fired porcelain, and the conductor via is made of a low-resistance metal such as copper, aluminum or silver, thereby reducing the occurrence of conductor loss and the like. be able to.

In particular, the dielectric constant of the dielectric via is twice or more higher than the dielectric of the dielectric waveguide, so that the performance as a resonator can be improved.

A filter can be formed by arranging a plurality of dielectric waveguide resonators in series.

According to the dielectric waveguide resonator and the filter of the present invention, a dielectric material having a dielectric constant higher than the dielectric material of the dielectric material forming the dielectric waveguide in the cut-off waveguide having a fixed width. Since the resonator can be formed by forming the dielectric via, even when the signal frequency is high, the width of the dielectric waveguide forming the resonator can be formed with a constant width, and the dielectric waveguide can be formed. The conductor vias forming the side wall of the tube can be formed at a constant pitch, and are easy to design and easy to manufacture.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a perspective view for explaining a detailed structure of a dielectric waveguide according to the present invention. FIGS. 2 and 3 show one embodiment of a dielectric waveguide resonator and a filter according to the present invention. It is a schematic perspective view shown. In addition,
In the drawings, all are shown in a transmission diagram without the dielectric, and FIG.
In the above, the conductor via on the E-plane of the waveguide is omitted as it forms a pseudo conductor wall. In the figure, 1 is a dielectric waveguide, 2 is an input port, 3 is an output port, and 4 is a resonator.

As shown in FIG. 1, a dielectric waveguide 1 according to the present invention has a pair of conductor layers 1a above and below a predetermined dielectric.
1b are arranged in parallel at a predetermined interval t to form an H plane, and an E plane perpendicular to the conductor layers 1a and 1b, that is, so as to electrically connect the conductor layers 1a and 1b, ie, Conductor vias 1c are arranged in two rows with a width z at a predetermined interval x to form side walls. The distance x between the conductor vias 1c is
The interval is set to less than 1/2 of the signal wavelength. The width w1 of the waveguide is usually 0.65 to 0.95 times the signal wavelength.
Set to double. Also, the interval t between the conductor layers 1a and 1b
Is set to w1 / 2. The distance x between the conductor vias 1c is important for preventing signal leakage from leaking from the side wall.

Further, in the dielectric waveguide 1, the conductor vias 1c adjacent to the conductor vias 1c
The conductor band 1d for electrically connecting the conductor bands to the conductor layers 1a and 1b
When the dielectric waveguide 1 is formed in parallel, the side wall of the dielectric waveguide 1 can be formed by a grid composed of the conductor formed by the conductor via 1c and the conductor band 1d. Can be.

On the other hand, according to the dielectric waveguide resonator 1 of FIG. 2, the dielectric waveguide of FIG. 1 has a basic structure.
An input port 2 is provided at one end of the dielectric waveguide 1, and an output port 3 is provided at the other end. And, between the input port 2 and the output port 3, the width w1 of the waveguide
A portion formed by w2 which is narrower than that is formed. As described above, when the width is set to be smaller than the waveguide width w1 through which a signal can be transmitted, specifically, when the width is set to less than １ ／ of the signal wavelength,
In this part, the signal cannot be propagated. Such a portion is called a cutoff waveguide d.

According to the present invention, the cut-off waveguide d
In the region, the conductor layers 1 formed above and below the dielectric waveguide 1
a, a via is formed through the dielectric so as to connect the dielectric with the dielectric having a dielectric constant εd higher than the dielectric constant εr of the dielectric in the dielectric waveguide in the via. Filled dielectric vias 5 are formed. Also,
According to the dielectric waveguide resonator of FIG. 2, three dielectric vias 5 are arranged in a line along the central axis of the waveguide with a center distance a. As described above, the resonator 4 is formed by forming the dielectric via 5 in the cut-off waveguide d and increasing the effective permittivity of a part of the cut-off waveguide d. .

The number of the dielectric vias 5 may be one or more. However, in order to partially increase the effective dielectric constant, it is desirable to form a plurality of the dielectric vias. Also, the plurality of dielectric vias 5
In the cut-off waveguide d, they may be arranged in a line as shown in FIG. 2 or may be arranged in two lines as shown in FIG. Arranging in two rows in this manner has an advantage that the length of the resonator can be reduced as compared with the case of one row as shown in FIG.

The resonance frequency of the resonator 4 can be adjusted by the dielectric constant εd of the dielectric filled in the dielectric via 5, its number, or the position in the width direction of the waveguide.
In particular, the dielectric constant εd of the dielectric to be filled is desirably at least twice the dielectric constant εr of the dielectric in the dielectric waveguide.

The diameter of the dielectric via 5 is determined in consideration of necessary resonance characteristics. From the viewpoint of processing, the diameter is not more than twice the thickness of the dielectric sheet forming the dielectric waveguide. It is desirable.

FIG. 4 is a schematic perspective view showing another embodiment of the present invention. The dielectric waveguide resonator of FIG. 4 includes three resonators 4a, 4a in a cutoff waveguide d.
b, 4c. In this case, the cut-off in the waveguide d, in each resonator, the dielectric vias 5a, 5b, between the centers 5c respectively distances a _1, a _2, a ₃
It is arranged with. And the resonators 4a, 4b,
4c are formed apart from each other at intervals of e ₁ and e ₂ .

In the resonator having such a structure, the resonator 4
a, 4b, and 4c, ie, the dielectric via 5
a, 5b, 5c and the length dL of the cut-off waveguide
By adjusting the in the band outside the center frequency,
The amount of attenuation can be adjusted.

The resonator characteristics can be adjusted by adjusting the relative permittivity of each dielectric via 5. Further, in the above-described three embodiments shown in FIGS. 2, 3, and 4,
Although the dielectric via 5 penetrates the dielectric waveguide from the conductor layer 1a to the conductor layer 1b, the dielectric via 5 does not necessarily need to penetrate the conductor layer 1a and the dielectric in the conductor layer 1b. For example, in the case where the dielectric waveguide itself is formed by a laminate of multiple dielectric layers, the conductor layers 1a and 1
The dielectric via can be formed only in a specific dielectric layer between the first and second dielectric layers.

Further, it is desirable that the dielectric material forming the dielectric waveguide be a ceramic material which can be fired at a low temperature. According to the present invention, it is necessary to embed a dielectric material different from the dielectric material in the dielectric waveguide in the dielectric via 5 according to the present invention. This is to minimize the reaction with In particular, when a material that can be fired at a temperature of 1050 ° C. or less is used, the conductor via 1c and the conductor band 1d that form the E plane are formed together with at least one low-resistance metal selected from the group consisting of copper, silver, and aluminum. can do. Examples of the ceramic material which can be fired at a low temperature include, for example, borosilicate glass powder or 10 to 90% by volume of glass powder.
And at least one selected from the group consisting of alumina, silica, mullite, and aluminum nitride at a ratio of 10 to 90% by volume and firing at a temperature of 800 to 1050 ° C.

In the dielectric waveguide resonator of the present invention, for example, the conductor layers 1a and 1b, the conductor vias 1c, and the conductor bands 1d are printed and applied with a conductor paste on a plurality of ceramic green sheets, respectively. Patterning is performed using a foil or the like. At the same time, a predetermined via is filled with a dielectric paste. The green sheets thus produced can be produced by aligning the laminated sheets, laminating and integrating them, and then firing them at a predetermined temperature.

The filter can be formed by combining dielectric waveguide resonators having predetermined resonance characteristics.

[0029]

EXAMPLE 1 A resonator according to an embodiment of the present invention shown in FIG. 2 was connected in series.
FIG. 5 shows the resonator characteristics.
The parameters in this filter were as follows.
The basic dielectric waveguide has a relative permittivity εr = 4.9 and a waveguide
Width W₁= 1.6 mm, waveguide thickness t = 0.48 mm
The resonator 4 has a width W of the cut-off waveguide. _Two= 0.8m
m, cut-off waveguide length dL = 2.6 mm, dielectric
A) The relative permittivity εd of the dielectric in the dielectric layer = 20.0, and the diameter of the dielectric via
b = φ0.2mm, dielectric via pitch (center-to-center distance) a
= 0.5 mm. The dielectric via 5 is cut off.
They were arranged in a line on the central axis of the waveguide d.

In this case, as shown in FIG. 5, a characteristic having a resonance frequency of 73.2 GHz and a frequency band of 0.5 GHz are obtained, which indicates that such a structure functions as a resonator.

Example 2 A filter was manufactured using a resonator based on the embodiment of the present invention shown in FIG. 3, and the resonator characteristics were shown in FIG. The parameters in the filter of FIG. 6 were as follows. The basic dielectric waveguide was set the same as in the first embodiment. The resonator 4 is
Cut-off waveguide width W ₂ = 0.8 mm, cut-off waveguide length dL = 2.0 mm, dielectric constant εd of dielectric via =
20.0, dielectric via diameter b = φ0.2 mm, and dielectric via pitch a = 0.4 mm. The dielectric via group was arranged at the center of the cutoff waveguide.

In this case, the resonance frequency is 74.1 GHz,
The frequency band has a characteristic of 0.9 GHz, which indicates that it functions as a resonator. As can be seen from comparison with FIG. 5 according to the first embodiment, it is understood that the resonance characteristics can be adjusted by adjusting the arrangement of the dielectric vias and the length of the cutoff waveguide.

Example 3 A filter was manufactured by using a resonator based on the embodiment of the present invention shown in FIG. 4, and the resonator characteristics were shown in FIG. The parameters in the filter of FIG. 4 were as follows. The basic dielectric waveguide is the same as that of the first embodiment. The resonator 4 has a cut-off waveguide width W ₂ = 0.8 mm and a cut-off waveguide length dL.
= 7.2 mm, relative permittivity εd of dielectric vias 5a, 5b, 5c = 20.0, dielectric via diameter b = φ0.2 mm, dielectric via pitch (a ₁ , a ₂ , a ₃ ) = 0.5 mm , Distance between the dielectric via groups (e ₁ = 1.57 mm, e ₂ = 1.57 mm
And The dielectric vias of the resonators 4a, 4b and 4c were arranged in a line at the center of the cutoff waveguide. The dielectric via group of the resonator 4 was arranged at a position shifted by 0.03 mm from the center of the cutoff waveguide.

In this case, the center frequency is 73.3 GHz,
The frequency band has a characteristic of 0.7 GHz, and it can be seen that the filter functions as a filter having an attenuation of -20 dB or less at ± 1 GHz on both sides of the center frequency.

[0035]

As described above in detail, according to the dielectric waveguide resonator and the filter of the present invention, regardless of the level of the signal frequency, the side wall is formed by the conductor via or the conductor via and the conductor layer. Since the waveguide can be easily formed, the design of the resonator and the filter is facilitated. further,
According to a conventional method of manufacturing a multilayer substrate, a resonator and a filter can be easily incorporated in various multilayer substrates.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view for explaining the structure of a dielectric waveguide according to the present invention.

FIG. 2 is a schematic perspective view showing one embodiment of the dielectric waveguide resonator of the present invention.

FIG. 3 is a schematic perspective view showing another embodiment of the dielectric waveguide resonator of the present invention.

FIG. 4 is a schematic perspective view showing still another embodiment of the dielectric waveguide resonator of the present invention.

FIG. 5 shows resonator characteristics of a filter manufactured by using the resonator shown in FIG. 2;

FIG. 6 shows resonator characteristics of a filter manufactured by using the resonator shown in FIG.

FIG. 7 shows the resonator characteristics of a filter manufactured by using the resonator shown in FIG.

FIG. 8 is a schematic perspective view for explaining the structure of a conventional waveguide filter.

FIG. 9 is a schematic plan view for explaining the structure of a filter using a conventional dielectric waveguide.

[Explanation of symbols]

 Reference Signs List 1 dielectric waveguide 1a, 1b conductor layer 1c conductor via 1d conductor band 2 input port 3 output port 4 resonator 5 dielectric via d cut-off conductor path

Claims (8)

[Claims] 1. A part of a dielectric waveguide formed in a dielectric substrate, wherein an H plane is formed of a conductor layer, and an E plane is formed of a group of conductor vias arranged at an interval of less than 1/2 of a signal wavelength. Forming a dielectric via made of a dielectric having a higher dielectric constant than the dielectric forming the dielectric waveguide in the cut-off waveguide. And a dielectric waveguide resonator. 2. The dielectric waveguide resonator according to claim 1, wherein a conductor band for electrically connecting adjacent conductor vias is formed in an E plane comprising said conductor via group. 3. The dielectric waveguide resonator according to claim 1, comprising a plurality of dielectric vias. 4. The dielectric waveguide resonator according to claim 3, wherein the resonance characteristics are adjusted by changing the arrangement of the plurality of dielectric vias. 5. The apparatus according to claim 1, wherein the dielectric vias are arranged on a central axis of the cut-off waveguide, or a plurality of dielectric vias are arranged at positions symmetrical with respect to the central axis. The dielectric waveguide resonator according to any one of claims 1 to 4. 6. The dielectric waveguide resonator according to claim 1, wherein the dielectric forming said dielectric waveguide is a low-temperature fired porcelain. 7. The dielectric waveguide according to claim 1, wherein the dielectric via has a dielectric constant at least twice as high as that of the dielectric in the dielectric waveguide. Resonator. 8. A filter comprising a plurality of dielectric waveguide resonators according to claim 1 arranged in series.