JPH08237007A - High frequency circuit device - Google Patents

Abstract

PURPOSE: To attain high performance by providing a radio wave absorbing body between a couple of guide paths so as to effectively suppress interference or resonance or the like between the guide paths thereby reducing a signal transmission loss. CONSTITUTION: First and second dielectric boards 2a, 2b are bonded via a radio wave absorbing body 3. The radio wave absorbing body 3 is preferably made of a resin with ferromagnetic material such as ferrite or iron impregnated thereto or a porous ceramics with ferromagnetic material impregnated thereto. Furthermore, a 1st strip conductor 4a (2nd strip conductor 4b) is formed respectively on an upper face of a 1st dielectric board 2a (2nd dielectric board 2b). The radio wave absorbing body 3 is formed integrally between the 1st and 2nd strip conductors 4a, 4b so as to be extended continuously along the 1st and 2nd strip conductors 4a, 4b. On the other hand, 1st (2nd) conductor planar board 5a(5b) is formed respectively on the rear side of the 1st dielectric board 2a (2nd dielectric board 2b).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency circuit device, and more particularly to a high frequency circuit device having a wave absorber provided between wirings.

[0002]

2. Description of the Related Art Conventionally, various studies have been made on a high frequency circuit device for processing a high frequency signal, and its development has been advanced. FIG. 5 is a perspective view showing an example of a conventional high frequency circuit device.

Referring to FIG. 5, insulator layers 6a and 6b made of glass, epoxy or the like are laminated.
Grounding metal layers 7a and 7b made of Cu or the like are formed so as to sandwich a and 6b from above and below. Insulator layers 6a, 6
A plurality of signal lines 8 are formed between b. And
Conductor through holes 9 are formed in the insulating layers 6a and 6b located between the signal lines 8. The conductor through hole 9 is formed by the grounding metal layers 7a and 7b and the insulator layers 6a and 6b.
It is formed by forming a plurality of through holes so as to penetrate b and then burying Cu or the like in the through holes by electroless plating or the like.

By forming the conductor through holes 9 as described above between the signal lines 8, it is possible to reduce crosstalk. The smaller the pitch of the conductor through holes 9, the more effective it is in reducing crosstalk.

[0005]

However, the above-mentioned conventional high-frequency circuit device has the following problems.

As described above, it is possible to reduce the crosstalk by reducing the pitch of the conductor through holes 9. However, in consideration of the manufacturing aspect and the mechanical strength of the high frequency circuit device, the conductor through holes can be reduced. The pitch of 9 has a lower limit. Therefore, a space is inevitably required between the conductor through holes 9, and there is a concern that radio waves may leak from the gap between the conductor through holes 9.

A wiring material such as Cu is used as the conductor filled in the conductor through hole 9. This is because if the conductor through-hole 9 is filled with a material capable of effectively absorbing electromagnetic waves, its resistance value becomes high. The volume of the wiring material filled in the conductor through hole 9 is also small. for that reason,
The electromagnetic wave absorption performance of the wiring material filled in the conductor through-hole 9 cannot be said to be very excellent.

From the above, in the conventional example shown in FIG. 5, the electric wave leaks through the gap between the conductor through holes 9 and the electric wave absorbing performance of the wiring material filled in the conductor through holes 9 Is not excellent,
It is considered that the function of preventing interference and resonance between wirings is insufficient. Therefore, it is considered that the signal transmission loss cannot be sufficiently reduced.

The present invention has been made to solve the above problems. An object of the present invention is to provide a high frequency circuit device that can effectively suppress interference and resonance between wirings.

[0010]

A high frequency circuit device according to the present invention has a pair of waveguides provided at intervals. And between this pair of waveguides, this 1
A radio wave absorber is integrally provided so as to extend along the pair of waveguides.

[0011]

In the high frequency circuit device according to the present invention, the radio wave absorber is integrally provided so as to extend along the pair of waveguides. Since the electromagnetic wave absorber is integrally provided so as to extend along the waveguide in this manner, no gap is formed unlike the case of the conductor through hole 9 in the above-mentioned conventional example.
As a result, it is possible to more effectively prevent the radio wave propagating in one waveguide from leaking to the other waveguide side than in the conventional example. As a result, it becomes possible to more effectively suppress the interference and resonance between the waveguides as compared with the conventional example. Further, since the material of the electromagnetic wave absorber can be selected without considering the resistance of the electromagnetic wave absorber, it is possible to select a material having excellent electromagnetic wave absorbing performance such as a ferromagnetic material as the material of the electromagnetic wave absorber. As a result, the electromagnetic wave absorption performance of the electromagnetic wave absorber itself can be made higher than the electromagnetic wave absorption performance of the conductor through hole 9 in the conventional example. Further, since the electromagnetic wave absorber is integrally provided so as to extend between the waveguides, the volume of the electromagnetic wave absorber can be increased more than the volume of the conductor embedded in the conductor through hole 9 in the conventional example. Becomes This also contributes to the improvement of the electromagnetic wave absorption performance of the electromagnetic wave absorber.

[0012]

Embodiments of the present invention will be described below with reference to FIGS.

(First Embodiment) First, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG.
FIG. 1 is a perspective view showing a high frequency circuit device according to a first embodiment of the present invention. 1 shows a microstrip line 1 to which the present invention is applied as an example of a high frequency circuit device.

Referring to FIG. 1, first and second dielectric substrates 2a and 2b are joined via a radio wave absorber 3. The materials for the first and second dielectric substrates 2a and 2b are:
Ceramics such as alumina may be mentioned. It should be noted that a ceramic porous body containing at least one selected from the group consisting of SiO ₂ , Si ₃ N ₄ , Al ₂ O ₃ , AlN and MgO is used as the first and second dielectric substrates 2a,
The material of 2b may be selected. In this case, by adjusting the porosity of the ceramic porous body to 50% or more and 90% or less, the relative dielectric constant of the ceramic porous body can be made as low as about 3.5 or less. The radio wave absorber 3 is preferably made of a material in which a resin is impregnated with a ferromagnetic material such as ferrite or iron, or a material in which a ferromagnetic material is infiltrated into a porous ceramic body.

First and second strip conductors 4a and 4b are formed on the upper surfaces of the first and second dielectric substrates 2a and 2b, respectively. The above-mentioned radio wave absorber 3 is shown in FIG.
, The first and second strip conductors 4a,
4b between the first and second strip conductors 4a, 4
It is integrally provided so as to continuously extend along b. Thereby, the first and second strip conductors 4a, 4
It is possible to effectively suppress the interference and resonance between b. Further, the radio wave absorber 3 may include a material having excellent radio wave absorption performance such as a ferromagnetic body as described above, and its volume may be larger than that in the conventional example shown in FIG. Become. This is also effective in suppressing interference and resonance between the first and second strip conductors 4a and 4b.

On the other hand, the first and second dielectric substrates 2a and 2b
The first and second flat conductor plates 5a and 5b are formed on the back surface of each.

Next, the planar structure and sectional structure of the microstrip line 1 shown in FIG. 1 will be described with reference to FIG. FIG. 2A is a plan view of the microstrip line 1 shown in FIG. 2 (b) is shown in FIG. 2 (a).
IIb-IIb line sectional view.

First, referring to FIG. 2A, the length L of the microstrip line 1 is, for example, 10 mm, and the width W1.
Is 5 mm. In this case, the plane width W4 of the first and second strip conductors 4a and 4b is about 0.4 mm,
The plane width W2 of the radio wave absorber 3 is about 1.2 mm. Further, the first and second strip conductors 4a and 4b are spaced apart from the side end of the microstrip line 1 by a distance W of about 1 mm.
It is formed by opening 3.

Next, referring to FIG. 2B, the thickness t1 of the electromagnetic wave absorber 3 is about 0.4 mm. On the other hand, the thickness of the first and second dielectric substrates 2a and 2b is also about 0.4 mm.

Next, a method of manufacturing the microstrip line 1 having the above structure will be described. First,
Ceramics such as alumina 10mm × 1.9mm ×
Process to 0.4 mm ^t . Strain two such ceramics. These are the first and second dielectric substrates 2a and 2b. Then, the first and second strip conductors 4 are formed on the surfaces of the first and second dielectric substrates 2a and 2b.
First and second flat conductor plates (metallized layers) are formed on the a and 4b and the entire back surface by a mask coating method or a photolithography method.

Next, a radio wave absorber 3 is formed by impregnating a resin with a ferromagnetic material such as ferrite or iron, and the radio wave absorber 3 is formed.
Is cut into 10 mm × 1.2 mm × 0.4 mm ^t . Then, both side surfaces of the radio wave absorber 3 and one side surface of the first and second dielectric substrates 2a and 2b are bonded with an adhesive. As a result, the microstrip line 1 shown in FIG. 1 is formed.

Next, a manufacturing method in the case where a material obtained by infiltrating a ferromagnetic material into a ceramic porous body is used as the radio wave absorber 3 will be described. In this case, it is possible to improve the heat resistance (150 ° C. or higher) as compared with the case where the resin is used as described above.

First, by firing alumina at a temperature of about 1400 ° C., a porous body of alumina is formed without proceeding the firing. Then, iron is infiltrated into the porous body thus obtained. Thereby, the radio wave absorber 3 is formed. Then, the radio wave absorber 3 and the first and second dielectric substrates 2a and 2b are bonded using glass. Specifically, a glass paste is applied to one side surface of each of the first and second dielectric substrates 2a and 2b, and the radio wave absorber 3 is applied to the above glass paste of the first and second dielectric substrates 2a and 2b. Insert it on the side that has been applied. Then, the glass paste is fired in the firing furnace to bond the radio wave absorber 3 to the first and second dielectric substrates 2a and 2b. The heat resistant temperature also changes depending on the type of glass used in this case.
For example, by using PbO glass at 400 ° C
The heat resistance up to 800 ° C. can be obtained by using borosilicate glass.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS. FIG.
FIG. 6 is a perspective view showing a microstrip line 1 according to a second embodiment of the present invention.

Referring to FIG. 3, in this embodiment, 1
First and second strip conductors 4a and 4b are formed on the upper surface of one dielectric substrate 2 at intervals. A groove is formed on the upper surface of the dielectric substrate 2 located between the first and second strip conductors 4a and 4b, and the radio wave absorber 3 is joined to the groove. A flat conductor plate 5 is formed on the entire back surface of the dielectric substrate 2. The other structure is the same as that of the first embodiment shown in FIG.

Since the microstrip line 1 in this embodiment has the above structure, the following effects can be obtained. That is, since the radio wave absorber 3 may be installed and joined in the groove, the radio wave absorber 3 and the dielectric substrate 2 can be joined more easily than in the first embodiment. Also,
As in the case of the first embodiment described above, it is possible to effectively suppress the interference and resonance between the first and second strip conductors 4a and 4b.

Next, the sectional structure of the microstrip line 1 shown in FIG. 3 taken along the line IV-IV will be described with reference to FIG. FIG. 4 is a view showing a cross section taken along line IV-IV in FIG.

Referring to FIG. 4, the dielectric substrate 2 remains below the radio wave absorber 3. The thickness t2 of the radio wave absorber 3 is about 0.2 mm. Also, the radio wave absorber 3
The sum t1 of the thickness t2 and the thickness of the dielectric substrate 2 located under the radio wave absorber 3 is about 0.4 mm. The dimensions of the other components shown in FIG. 3 are the same as in the case of the first embodiment.

Next, a modified example of the second embodiment will be described. In this modification, the dielectric substrate 2 is made of a porous ceramic body. Preferably 50
The dielectric substrate 2 is composed of a porous ceramic body having a porosity of not less than 90% and not more than 90%. Then, a part of the dielectric substrate 2 is transformed into the radio wave absorber 3 by selectively infiltrating a ferroelectric substance such as iron into the dielectric substrate 2. At this time, the first and second strip conductors 4a, 4a
The above infiltration treatment is performed without placing iron on the portion where b is formed. Thereby, the dielectric substrate 2 in which the radio wave absorber 3 is partially formed is obtained.

Then, the first and second strip conductors 4a and 4b are formed on the surface of the dielectric substrate 2 so as to sandwich the radio wave absorber 3 by using a mask vapor deposition method or the like. Also in the case of this modification, substantially the same effects as those of the first and second embodiments can be obtained. In this modification, since the dielectric substrate 2 is made of a ceramic porous body having a low relative permittivity, the plane width W4 of the first and second strip conductors 4a and 4b is as thick as about 0.8 mm. It becomes possible to do.

Next, the usefulness of the radio wave absorber 3 according to the present invention will be described with reference to Table 1 below. The inventor of the present invention has found that the microstrip line 1 according to each of the above-described embodiments.
If, to prepare a microstrip line without the wave absorber as a comparative example, the S _11, S _21, 2 two lines (first and second strip conductors 4a, 4b) S ₂₁ between at 20GH _z It was measured by a network analyzer.

The results are shown in Table 1 below.

[0033]

[Table 1]

In Table 1 above, as a comparative example, the microstrip line 1 shown in FIG. 3 in which the groove and the electromagnetic wave absorber 3 were not formed was used. Although this comparative example has a different structure from the conventional example, it is considered appropriate to compare this comparative example with the device according to the present invention in order to show the usefulness of the radio wave absorber 3. In Table 1, the prototype 1 is obtained by joining the resin wave absorber 3 in the above-described Example 1 with the epoxy adhesive. Prototype 2 is
Radio wave absorber 3 made of porous alumina in Example 1
And is joined with PbO glass. Prototype 3
Is the one in which the alumina wave absorber 3 of Example 1 was joined with borosilicate glass. The prototype 4 is obtained by joining the resin wave absorber 3 in Example 2 with an adhesive. The trial manufacture 5 is one in which the radio wave absorber 3 of the porous alumina body is bonded to the groove provided in the dielectric substrate 2 with PbO glass in the above-described second embodiment. The prototype 6 is obtained by joining the alumina porous electromagnetic wave absorber 3 to the groove provided in the dielectric substrate 2 using borosilicate glass in Example 2 described above. Prototype 7 is obtained by infiltrating iron into the central portion of dielectric substrate 2 made of an alumina porous body in the modification of Example 2 described above.

[0035] As shown in Table 1 above, prototype 1-7 according to the present invention, S _11, S _21, for any of the S ₂₁ between lines, it showed better performance than the comparative example I understand. Further, it can be seen that S ₂₁ between the lines exhibits particularly excellent characteristics. That is, the isolation property between the two strip conductors is particularly excellent. From this fact, it is considered that the present invention has a separation characteristic superior to that of the above-mentioned conventional example.

[0036]

As described above, according to the present invention,
By providing the radio wave absorber between the pair of waveguides, it is possible to effectively suppress the interference or resonance between the pair of waveguides. As a result, a high-performance high-frequency circuit device with less signal transmission loss can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view showing a microstrip line in a first embodiment of the present invention.

2A is a plan view of the microstrip line shown in FIG. 1. FIG. (B) is IIb- in (a).
It is sectional drawing which follows the IIb line.

FIG. 3 is a perspective view showing a microstrip line according to a second embodiment of the present invention.

4 is a cross-sectional view taken along the line IV-IV in FIG.

FIG. 5 is a perspective view showing an example of a conventional high-frequency circuit device.

[Explanation of symbols]

 1 Microstrip Line 2 Dielectric Substrate 2a First Dielectric Substrate 2b Second Dielectric Substrate 3 Radio Wave Absorber 4a First Strip Conductor 4b Second Strip Conductor 5 Flat Conductor Plate 5a First Flat Conductor Plate 5b Second flat conductor plate

Claims (6)

[Claims] 1. A high-frequency circuit device having a pair of waveguides provided at intervals, integrally with each other between the pair of waveguides so as to extend along the pair of waveguides. A high-frequency circuit device comprising the provided electromagnetic wave absorber. 2. The high frequency circuit device according to claim 1, wherein the pair of waveguides are respectively formed on a pair of substrates, and the pair of substrates are bonded to each other via the radio wave absorber. . 3. The pair of waveguides are formed on one substrate at intervals, and the substrate surface located between the pair of waveguides is provided along the pair of waveguides. The high frequency circuit device according to claim 1, wherein a groove is formed so as to extend, and the radio wave absorber is installed in the groove. 4. The pair of waveguides are formed on one substrate with a space therebetween, and a part of the substrate located between the pair of waveguides functions as the radio wave absorber. The high frequency circuit device according to Item 1. 5. The high frequency circuit device according to claim 1, wherein the radio wave absorber includes a ferromagnetic body. 6. The high frequency circuit device according to claim 2, wherein the waveguide is a planar waveguide, and the substrate is made of a ceramic porous body having a porosity of 50% or more and 90% or less.