JPH10215104A - Connection structure for dielectric waveguide line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use a dielectric waveguide line for forming a pseudo waveguide inside a dielectric in combination with another transmission line. SOLUTION: This structure is provided with a pair of main conductor layers 3a and 3b facing each other across at least a part of a dielectric substrate 1 and the group of the two columns of via holes 4 disposed with an interval less than 1/2 of an interruption wavelength in the transmission direction of electric signals for electrically connecting the pair of the main conductor layers 3a and 3b and is the structure for connecting the dielectric waveguide line 2 for transmitting the electric signals and the other transmission line 6 by a waveguide area surrounded by the main conductor layers 3a and 3b and the group of the via holes 4. In this case, one end 7' of the line conductor 7 of the other transmission line 6 is inserted inside the dielectric waveguide line 2 through a side face or an end face formed by the group of the via holes 4 of the dielectric waveguide line 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coupling structure between a dielectric waveguide line for transmitting high-frequency electric signals such as microwaves and millimeter waves and other transmission lines.

[0002]

2. Description of the Related Art Conventionally, strip lines, microstrip lines, coplanar lines and the like have been known as transmission lines for high frequency signals (having a frequency of 1 GHz or more) formed inside a wiring board or a high frequency package. I have. These transmission lines can be formed relatively easily by a lamination technique of printing conductors to be lines on a plurality of dielectric layers and laminating them, and an electric signal having a frequency in a microwave region. It has been widely used as a transmission line for high-frequency signals because of its excellent characteristics in transmission.

Recently, a pseudo rectangular waveguide is formed by a pair of main conductor layers sandwiching a dielectric substrate and two rows of via holes arranged between the main conductor layers. A waveguide waveguide has been proposed (Japanese Unexamined Patent Publication No. 6-53).
No. 711), a new type of transmission line having excellent transmission characteristics equivalent to that of a conventional rectangular waveguide and high productivity.

[0004] These various transmission lines are properly used depending on the transmission characteristics and applications.
Therefore, there is a demand for a technique of forming a plurality of different types of transmission lines inside a wiring board or the like and interconnecting them.

However, when connecting different types of transmission lines to each other, for example, a strip line and a microstrip line can be connected relatively easily by electromagnetically coupling their ends. Although,
No specific study has been made so far on the coupling structure between the dielectric waveguide line and other transmission lines as described above, and a combination of the dielectric waveguide line and other transmission lines should be used. Could not.

[0006]

Means for Solving the Problems The inventors of the present invention have repeatedly examined the coupling structure between the dielectric waveguide line and another transmission line, and as a result, have found that the coupling structure is formed through the side surface or end surface of the dielectric waveguide line. It has been found that a direct connection can be made by inserting a part of another transmission line and coupling it electromagnetically.

That is, the coupling structure of the dielectric waveguide line of the present invention electrically connects the pair of main conductor layers facing each other with at least a part of the dielectric substrate therebetween. And two rows of via holes arranged in the transmission direction of the electric signal at an interval of の or less of the cutoff wavelength, and the electric signal is formed by the waveguide region surrounded by the main conductor layer and the via hole group. And a structure for coupling a dielectric waveguide line for transmitting the dielectric waveguide line with another transmission line, wherein the dielectric waveguide line is formed through a side surface or an end surface formed by a via hole group of the dielectric waveguide line. It is characterized in that one end of a line conductor of another transmission line is inserted inside the waveguide line.

Further, in the coupling structure of the laminated waveguide of the present invention, the other transmission line is a coplanar line or a strip line.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic perspective view showing one embodiment of a coupling structure of a dielectric waveguide line according to the present invention, wherein 1 is a dielectric substrate, 2 is a dielectric waveguide line, and 3a and 3b are a pair of main conductors. The layer 4 is a via hole, 6 is a coplanar line as another transmission line, and 7 is a line conductor of the coplanar line 6.

The dielectric substrate 1 is made of a dielectric material such as alumina ceramics, glass ceramics and aluminum nitride ceramics. For example, when the dielectric substrate 1 is made of alumina ceramics, an organic solvent suitable for ceramic raw material powder such as alumina, silica, magnesia, etc. A plurality of ceramic green sheets are obtained by adding and mixing a solvent to form a slurry and forming the sheet into a sheet by employing a conventionally known doctor blade method, calender roll method, or the like. Are subjected to an appropriate punching process, stacked one above the other, and fired at a high temperature (about 1600 ° C.).

A dielectric waveguide line 2 and a coplanar line 6 are provided inside the dielectric substrate 1, and the two transmission lines are mutually coupled in the dielectric substrate 1. I have. The dielectric waveguide line 2 forms at least a part of the dielectric substrate 1, for example, the dielectric substrate 1.
A pair of main conductor layers 3a, 3b facing each other across the lower four layers of the dielectric layer 1a;
b are electrically connected to each other, and two rows of via holes (diameter of via hole 4: φ50 to 300 μm) arranged in the transmission direction of the electric signal at an interval c of １ ／ or less of the cutoff wavelength (λc).
m) and three sub-conductor layers 5 arranged between the pair of main conductor layers 3a and 3b in a state of being connected to the respective via holes 4.

In such a dielectric waveguide line 2, the two via-hole groups formed between the pair of main conductor layers 3a and 3b have a half of the cutoff wavelength (λc) in the electric signal transmission direction.
Since they are arranged at the following intervals c and form electric walls in a direction perpendicular to the direction of transmission of electric signals, electromagnetic waves can be propagated favorably only in the direction in which the lines are formed. Therefore, a region surrounded by the pair of main conductor layers 3a and 3b and the two rows of via holes is defined as a × b (a: distance between the pair of main conductor layers 3a and 3b, b: between two rows of via holes). ), And can be used as a transmission line suitable for transmitting high-frequency electric signals such as microwaves and millimeter waves. For example, when the mode of the electromagnetic wave propagating through the dielectric waveguide line 2 is the TE10 mode, the pair of main conductor layers 3a and 3b
The distance a between them was slightly larger than の of the central wavelength of the electric signal, and the distance b between the two rows of via holes was set to about a / 2 to form a pair of main conductor layers 3a and 3b. The plane is an E plane parallel to the electric field, and the plane surrounded by the via hole 4 and the sub-conductor layer 5 is an H plane parallel to the magnetic field.

Here, the reason why the arrangement pitch c of the via holes 4 is made equal to or less than 1/2 of the cutoff wavelength (λc) is that if the arrangement pitch c is larger than 1/2 of the cutoff wavelength (λc), This is because, when an electromagnetic wave is supplied to the waveguide line 2, the electromagnetic wave leaks from between the adjacent via holes 4, and the electric signal does not propagate well along the dielectric waveguide line 2. The arrangement pitch c needs to be set to １ ／ or less of the cutoff wavelength (λc).

The sub-conductor layer 5 serves to improve the effect of blocking electromagnetic waves by forming the side walls of the dielectric waveguide line 2 into a finer lattice shape. Are not indispensable components to construct.

On the other hand, the coplanar line 6 disposed inside the dielectric substrate 1 together with the dielectric waveguide line 2 is:
It is composed of a strip-shaped line conductor 7 and ground conductors 5 ′ arranged on both sides of the line conductor 7 by using a part of the sub-conductor layer 5, and propagates an electric signal through the line conductor 7. It is made to let.

Such a coplanar line 6 is formed on one surface of the dielectric layer 1a constituting the dielectric substrate 1. For example, the conductor width of the line conductor 7 is adjusted so that the characteristic impedance becomes 50Ω. The distance between the line conductor 7 and the ground conductor is set to 50 to 500 μm, and the distance between the line conductor 7 and the ground conductor is set to 50 to 500 μm.

The coplanar waveguide 6 and the pair of main conductor layers 3a and 3b, the via hole 4, the subconductor layer 5 and the line conductor 7 constituting the dielectric waveguide line 2 are made of an alumina ceramic. Is formed of a high melting point metal material such as tungsten or molybdenum, and is simultaneously provided inside the dielectric substrate 1 when the dielectric substrate 1 is manufactured. That is, a predetermined pattern having a thickness of 5 to 25 μm is formed on a surface of a plurality of ceramic green sheets serving as the dielectric substrate 1 by applying a conductive paste containing a metal powder such as tungsten or molybdenum by a conventionally known thick film printing method or the like. And a conductive paste is buried in a hole previously formed in the ceramic green sheet, and baked simultaneously with the ceramic green sheet to form a dielectric waveguide line 2 in the dielectric substrate 1.
And a coplanar line 6 are formed.

The dielectric waveguide line 2 and the coplanar line 6 are connected to one end (hereinafter referred to as a stub) of a line conductor 7 of the coplanar line 6 as shown in FIGS.
Is inserted into the dielectric waveguide line 2 through the side surface formed by the via hole group of the dielectric waveguide line 2 to achieve the coupling.

According to this coupling structure, the electric signal propagating through the coplanar line 6 is transmitted to the stub 7 ′ of the line conductor 7.
To generate a concentric magnetic field centered on the stub 7 '. Therefore, when the distance b between the two rows of via holes in the dielectric waveguide line 2 is set to a / 2, it is coupled to the propagating TE10 mode, and the dielectric waveguide line 2 and the coplanar line 6 A good connection will be made.

When the length d of the stub 7 'is set to 1/4 of the center wavelength of the electric signal to be propagated, the stub 7' performs the same operation as the 1/4 wavelength monopole antenna. The electric signal of the wavelength can be more efficiently radiated into the dielectric waveguide line 2. However, actually, a capacitance is generated with respect to the ground conductor on the right side of FIG. 2 and an inductance is generated with respect to the ground conductor on the lower side.
It is necessary to finely adjust the length d of the stub 7 'in consideration of the amount. Therefore, the length d of the stub 7' is a / 4 to a /
It is preferably set to 3.

If the distance e between the end face of the dielectric waveguide line 2 and the center of the stub 7 'is set to 1/4 of the guide wavelength of the electric signal to be propagated, the light is reflected at the end face and has the opposite phase. The resulting electromagnetic wave is added in the same phase as the electromagnetic wave traveling without being reflected, so that good characteristics can be obtained. However,
Actually, a capacitance is generated with respect to the ground conductor on the right side of FIG. 2 and an inductance is generated with respect to the ground conductor on the lower side. Therefore, the end face of the dielectric waveguide line 2 and the stub 7 'are taken into account in consideration thereof. It is necessary to finely adjust the distance e from the center. For this reason, the distance e is preferably set to a / 4 to a / 3.

It should be noted that the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made without departing from the spirit of the present invention. Although a line is used, a strip line 6 'composed of a strip-shaped line conductor 8 and a part of the sub-conductor layer 5' may be used instead, as shown in FIG. In this case, since the electromagnetic wave propagating through the strip line 6 ′ excites the stub 8 ′ and generates a concentric magnetic field, this is coupled with the mode propagating through the dielectric waveguide line 2 to form a transmission line. Can be satisfactorily combined. Further, in the above-described embodiment, the stub 7 'of the line conductor 7 of the coplanar line 6 inserted into the dielectric waveguide line 2 has a width substantially equal to other portions of the line conductor 7, but instead of this, As shown in FIG. 5, the stub 9 'of the line conductor 9 of another transmission line such as a coplanar line inserted into the dielectric waveguide line can be made wider than other portions of the line conductor 9. If this is the case, the mismatch between the characteristic impedances of the coplanar waveguide and the dielectric waveguide can be effectively mitigated to improve the transmission characteristics. Therefore, it is preferable that the stub 9 'of the line conductor 9 of the other transmission line inserted into the dielectric waveguide is wider than the other portion of the line conductor 9.

Further, in the above-described embodiment, the stub 7 'of the line conductor 7 of the coplanar line 6 is connected to the dielectric waveguide line 2 via the side surface of the dielectric waveguide line 2 formed by a group of via holes.
6 was inserted inside, but instead of this, FIG.
As shown in FIG. 5, a stub 10 'of a line conductor 10 of another transmission line such as a coplanar line may be inserted into the dielectric waveguide line 2 through an end face of the dielectric waveguide line 2. I do not care. In this case, by coupling with the electromagnetic wave of the TE11 mode, the coupling with the electromagnetic field is favorably performed.

[0024]

According to the present invention, it is possible to easily and satisfactorily connect a dielectric waveguide line to another transmission line, and to connect another dielectric waveguide line inside one wiring board or the like. Can be used in combination with the transmission line.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing one embodiment of a coupling structure of a dielectric waveguide line according to the present invention.

FIG. 2 is a plan view showing one main surface of a dielectric layer provided with another transmission line.

FIG. 3 is a sectional view taken along line XX of FIG. 2;

FIG. 4 is a schematic perspective view showing another embodiment of the coupling structure of the dielectric waveguide according to the present invention.

FIG. 5 is a plan view showing another embodiment of the coupling structure of the dielectric waveguide according to the present invention.

FIG. 6 is a plan view showing another embodiment of the coupling structure of the dielectric waveguide according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Dielectric substrate 2 ... Dielectric waveguide line 3a, 3b ... A pair of main conductor layers 4 ... Via holes 5, 5 ' ... Subconductor layer 6,6 '... Other transmission line 7,8,9,10 ... Line conductor 7', 8 ', 9', 10 '... Line conductor One end of

Claims (2)

[Claims] 1. A pair of main conductor layers opposed to each other with at least a part of a dielectric substrate interposed therebetween, and the pair of main conductor layers are electrically connected to each other. A dielectric waveguide line that transmits an electric signal through a waveguide region surrounded by the main conductor layer and the via hole group, and another transmission line. A line conductor of another transmission line inside the dielectric waveguide line via a side surface or an end surface formed by a via hole group of the dielectric waveguide line. Characterized in that one end of the laminated waveguide line is inserted. 2. The coupling structure of a dielectric waveguide line according to claim 1, wherein said another transmission line is a coplanar line or a strip line.