JPH1168416A - Dielectric waveguide line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dielectric waveguide line having high transmission characteristics which do not radiate nor leak electromagnetic waves of a high frequency signal even when a bent part exists in a transmission line and have reduced transmission losses. SOLUTION: This waveguide line is provided with a pair of conductive layers 2 holding a dielectric substrate in-between, and two lines of through conductive groups 4 formed at a repetitive interval (p) less than a half of cutoff wavelength and fixed width (d). In the above structure, bent parts are formed on the two lines of the conductive groups 4, one line arranged on the bent part position is formed like a broken line having one through conductor 6 as a bent point, and the other line is formed like a circular arc having the fixed width (d) as a radius. Consequently the radiation of electromagnetic waves on the bent can be almost eliminated and a high frequency signal can be transmitted with a low transmission loss.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric waveguide line for transmitting a high frequency signal in a microwave band, a millimeter wave band or the like.

[0002]

2. Description of the Related Art In a high-frequency circuit for handling a high-frequency signal such as a microwave band or a millimeter wave band, a transmission line for transmitting a high-frequency signal is required to be small and small in transmission loss. Since it is advantageous in terms of miniaturization if it can be formed on or in a substrate, strip lines, microstrip lines, coplanar lines, dielectric waveguide lines, and the like have been conventionally used as such transmission lines.

[0003] Among them, strip lines, microstrip lines and coplanar lines are composed of a signal line comprising a dielectric substrate and a conductor layer and a ground conductor layer, and the space around the signal line and the ground conductor layer and the dielectric material are formed. Although electromagnetic waves of high-frequency signals propagate through the inside, these lines have no problem for signal transmission up to the 30 GHz band, but transmission loss easily occurs at 30 GHz or higher.

On the other hand, a waveguide type line is advantageous in that the transmission loss is small even in a millimeter wave band of 30 GHz or more. Formable lines have also been proposed.

For example, in JP-A-6-53711,
There has been proposed a waveguide line in which a dielectric substrate is sandwiched between a pair of conductor layers, and a sidewall is formed by a plurality of rows of via holes connecting the conductor layers. According to this waveguide line, the area inside the conductor wall is used as a signal transmission line by surrounding the four sides of the dielectric material with a pseudo conductor wall formed by the conductor layer and the via hole. Thus, the size of the entire apparatus can be reduced.

[0006]

Generally, when a high-frequency circuit is formed, it is often inevitable to provide a bent portion in a wiring circuit of a transmission line.

However, in a dielectric waveguide line proposed in Japanese Patent Application Laid-Open No. Hei 6-53711, a signal transmission signal surrounded by a pair of conductor layers and pseudo conductor walls formed by two rows of via holes. When a bent portion is simply provided on a line, there is a problem that a transmission loss increases because an electromagnetic field is disturbed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object the advantage that even if a bent portion exists in a transmission line, electromagnetic waves of high-frequency signals are not radiated or leaked and transmission loss is small. An object of the present invention is to provide a dielectric waveguide line having transmission characteristics.

[0009]

Means for Solving the Problems The present inventors have studied the above problems, and as a result, have found that a dielectric waveguide line has two rows of via holes provided in a dielectric substrate. The via holes of the two rows of via holes are arranged in a predetermined arrangement at the bent portion provided in the transmission line having a structure formed by completely covering the pair of conductor layers electrically connected to the via holes. It has been found that even if there is a bent portion in the transmission line, there is almost no radiation and leakage of high-frequency signal electromagnetic waves, and good transmission characteristics with low transmission loss can be achieved.

A dielectric waveguide line according to the present invention has a pair of conductor layers sandwiching a dielectric substrate, and a repetition interval in a transmission direction of a high-frequency signal at a half or less of a cutoff wavelength of the high-frequency signal, and A two-row penetrating conductor group formed to electrically connect the conductor layers with a constant width in a direction perpendicular to the transmission direction, and a region surrounded by the conductor layer and the penetrating conductor group. A dielectric waveguide line for transmitting a high-frequency signal, wherein the two rows of through conductor groups have a bent portion in a part thereof, and one row located at the bent portion is connected to one through conductor by a bending point. And the other row is formed in an arc shape having the one width as the center and the radius having the constant width.

Further, the dielectric waveguide line according to the present invention has a pair of conductor layers sandwiching a dielectric substrate and a repetition interval in a transmission direction of a high-frequency signal at a half or less of a cutoff wavelength of the high-frequency signal. And two rows of through conductor groups formed so as to electrically connect the conductor layers with a constant width in a direction orthogonal to the transmission direction, and are surrounded by the conductor layers and the through conductor groups. A dielectric waveguide line for transmitting a high-frequency signal by a region, wherein the two rows of through conductor groups have a bent portion in a part thereof, and one row located in the bent portion has one bend.
Two through conductors are formed in a polygonal line shape having a bending point, and the other row is a polygonal line shape corresponding to the base of an isosceles triangle having the height of the certain width with the bending point of the one row as a vertex. It is characterized by being formed.

Further, the dielectric waveguide line of the present invention has a pair of conductor layers sandwiching a dielectric substrate and a repetition interval in a transmission direction of a high-frequency signal at a half or less of a cutoff wavelength of the high-frequency signal. And two rows of through conductor groups formed so as to electrically connect the conductor layers with a constant width in a direction orthogonal to the transmission direction, and are surrounded by the conductor layers and the through conductor groups. A dielectric waveguide line for transmitting a high-frequency signal by a region, wherein the two rows of through conductor groups each have a bent portion in which each row is arranged in a concentric arc shape.

According to the dielectric waveguide line of the present invention, the pair of conductor layers sandwiching the dielectric substrate and the repetition interval in the transmission direction of the high-frequency signal are equal to or less than half the cutoff wavelength of the high-frequency signal. And two rows of through conductor groups formed so as to electrically connect the conductor layers with a certain width in a direction orthogonal to the transmission direction. A part corresponding to a pseudo conductor wall parallel to the E-plane and the H-plane or the H-plane and the E-plane of the body waveguide is formed. Therefore, a transmission line for a high-frequency signal having a characteristic similar to that of a dielectric waveguide in a flat plate structure using a dielectric substrate can be obtained.

According to the dielectric waveguide line of the present invention, when providing a bent portion in the wiring of the transmission line,
By arranging the through conductor group of the row in the specific structure,
There is almost no electromagnetic wave radiation at the bent portion, and the transmission loss is small and good transmission characteristics are obtained.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. 1 and 2 are a schematic perspective view and a plan view, respectively, for explaining an example of an embodiment of a dielectric waveguide line according to the present invention. In these figures,
1 is a dielectric substrate, 2 is a pair of conductor layers sandwiching the dielectric substrate 1, 3 is a through conductor formed to electrically connect the pair of conductor layers 2, and 4 is a transmission direction of a high-frequency signal. A constant width d at a repetition interval p equal to or less than half the cutoff wavelength of the high-frequency signal and in a direction orthogonal to the transmission direction.
Are two rows of through conductor groups formed by disposing the through conductors 3.

According to FIG. 1, a pair of conductor layers 2 are formed at positions sandwiching a flat dielectric substrate 1 having a predetermined thickness a. The conductor layers 2 are formed on the upper and lower surfaces of the dielectric substrate 1 sandwiching at least the transmission line forming position. A large number of through conductors 3 are provided between the conductor layers 2 to electrically connect the conductor layers 2 to each other. As shown in FIGS. 1 and 2, these through conductors 3 are arranged at a predetermined repetition interval p which is equal to or less than half the cutoff wavelength of the high-frequency signal transmitted through the line in the transmission direction of the high-frequency signal, that is, the line forming direction. In addition, the through conductor group 4 which is a transmission line is formed by being formed in two rows at a predetermined constant interval (width) d in a direction orthogonal to the transmission direction.

Since the TEM wave can propagate between the pair of conductor layers 2 arranged in parallel, the distance p between the through conductors 3 in each row of the through conductor group 4 is larger than half the cutoff wavelength. Then, even if this line is supplied with electromagnetic waves, it does not propagate along the pseudo waveguide made here. However, if the distance p between the penetrating conductors 3 is less than half the cutoff wavelength, an electric side wall is formed, and the electromagnetic wave cannot propagate in the direction perpendicular to the transmission line and is reflected. The light is then propagated in the direction of the transmission line. As a result, a good transmission characteristic very similar to that of a dielectric waveguide can be obtained in a region having a cross section of a × d size surrounded by the conductor layer 2 and the through conductor group 4 having such a structure.

Here, there is no particular limitation on the thickness a of the dielectric substrate 1, but when it is used in the single mode, it is preferably about one half or twice the fixed width d. In the example of FIG. 1, portions corresponding to the H plane and the E plane of the dielectric waveguide are formed by the conductor layer 2 and the through conductor group 4, respectively.
If the thickness a is about twice as large as the width d, portions corresponding to the E-plane and the H-plane of the dielectric waveguide are formed by the conductor layer 2 and the through conductor group 4, respectively.

Reference numeral 5 denotes an auxiliary conductor layer for electrically connecting the through conductors 3 forming each column of the through conductor group 4 to each other.
It is formed appropriately as required. 1 and FIG.
In this example, the through conductor groups 4 are formed in two rows, but the through conductor groups 4 are arranged in four or six rows to form pseudo conductor walls formed by the through conductor groups 4 in two or three layers. By doing
Leakage of electromagnetic waves from the conductor wall can be prevented more effectively.

According to such a waveguide structure, to 1 / epsilon _r ^1/2 the size of the relative permittivity of the dielectric substrate 1 and epsilon _r is the waveguide size conventional waveguide Become. Therefore, as the material constituting the dielectric substrate 1 has a higher relative dielectric constant, the waveguide size can be reduced, and a multilayer wiring board or a semiconductor element housing package in which wiring is formed with high density can be formed. This is a size that can be used as a transmission line.

As shown in FIGS. 1 and 2, the dielectric waveguide line of the present invention has a bent portion in a part of the through conductor group 4 which is the transmission line, and has a bent portion inside the bent portion. One row positioned is formed in a polygonal line shape with one through conductor 6 as a bending point, and the other row positioned outside is formed in an arc shape centered on the one through conductor 6. It is characterized by the following. Such a bent portion has a structure as shown in FIG. 2, for example.

As shown in FIG. 2, the width of the line orthogonal to the transmission direction of the high-frequency signal at the bent portion has a constant width d.
The through conductor group 4 is arranged so that the through conductor group 4 located inside the bent portion is arranged in a broken line with one through conductor 6 as a bending point. On the other hand, the rows of the through-conductor groups 4 located outside the bent portion are arranged so as to draw an arc having a radius d around one through-conductor 6 which is a bending point of the row inside the bent portion.

The through conductors 3 constituting the through conductor group 4
Are arranged at a repetition interval p equal to or less than a half of the cutoff wavelength as described above. The repetition interval p is desirably a constant repetition interval in order to realize good transmission characteristics. It goes without saying that the interval may be changed as appropriate or some values may be combined as long as the interval is equal to or less than half the cutoff wavelength. Therefore, the repetition interval p of the through conductors 3 forming the row of the through conductor group 4 corresponding to the outside of the bent portion is also set to a constant value in order to sufficiently suppress the radiation of the electromagnetic wave and realize the good transmission characteristics. However, similarly, it may be changed variously at a value equal to or less than half the cutoff wavelength.

The dielectric substrate 1 according to the present invention is not particularly limited as long as it functions as a dielectric and has a characteristic that does not hinder the transmission of a high-frequency signal. It is desirable that the dielectric substrate 1 be made of ceramics from the viewpoint of easiness of manufacture.

As such ceramics, ceramics having various relative dielectric constants are known.
In order to transmit a high-frequency signal by the waveguide line of the present invention, it is desirable that the waveguide line be a paraelectric substance. This is because ferroelectric ceramics generally have large dielectric loss and high transmission loss in a high frequency range. Therefore, the relative dielectric constant ε _r of the dielectric substrate 1 is suitably about 4 to 100.

In general, the line width of a wiring layer formed on a multilayer wiring board or a package for housing a semiconductor element has a maximum of 1
mm, the minimum frequency that can be used is 15 GHz when a material having a relative dielectric constant of 100 is used and the upper surface is an H plane, that is, an electromagnetic field distribution in which the magnetic field is wound parallel to the upper surface. , And can be used in the microwave band region. On the other hand, a dielectric made of a resin generally used as the dielectric substrate 1 has a relative dielectric constant ε _r of about 2, and therefore cannot be used unless the line width is 1 mm or more than about 100 GHz. Becomes

Further, among such paraelectric ceramics, many have very small dielectric loss tangents, such as alumina and silica, but not all paraelectric ceramics can be used. In the case of a dielectric waveguide line, there is almost no loss due to the conductor, and most of the loss during signal transmission is due to the dielectric, and the loss due to the dielectric α
(DB / m) is expressed as follows. α = 27.3 × tanδ / λ / ｛1- (λ / λc) ² ｝ ^1/2 where tanδ: dielectric loss tangent of dielectric λ: wavelength in dielectric λc: cut-off wavelength Standardized rectangular waveguide According to the (WRJ series) shape, {1- (λ / λc) ² } ^1/2 in the above equation is about 0.75.

Therefore, the transmission loss is practically usable.
In order to make it 100 (dB / m) or less, it is necessary to select a dielectric so that the following relationship is satisfied.

F × ε _r ^1/2 × tan δ ≦ 0.8 where f is a frequency (GHz) to be used.

Examples of such a dielectric substrate 1 include alumina ceramics, glass ceramics, and aluminum nitride ceramics. For example, an appropriate organic solvent or solvent is added to and mixed with ceramic raw material powder to form a slurry. A plurality of ceramic green sheets are obtained by forming a sheet by employing a conventionally known doctor blade method or calender roll method, and thereafter, each of these ceramic green sheets is subjected to appropriate punching and laminated. It is manufactured by firing at a temperature of 1500 to 1700 ° C for alumina ceramics, 850 to 1000 ° C for glass ceramics, and 1600 to 1900 ° C for aluminum nitride ceramics.

When the dielectric substrate 1 is made of alumina ceramics, for example, a suitable oxide such as alumina, silica, magnesia, or an organic solvent or solvent is added to a metal powder such as tungsten when the dielectric substrate 1 is made of alumina ceramics. The mixed paste was printed on a ceramic green sheet by a thick film printing method so as to completely cover at least the transmission line, and then fired at a high temperature of about 1600 ° C.
It is formed so as to have a thickness of 15 μm or more. In the case of glass ceramics, copper / gold / silver is used as the metal powder,
Tungsten for aluminum nitride ceramics
Molybdenum is preferred. The thickness of the conductor layer 2 is generally about 5 to 50 μm.

The through conductor 3 may be formed of, for example, a via-hole conductor or a through-hole conductor.
The cross-sectional shape may be a polygon, such as a rectangle or a rhombus, in addition to a circular shape that is easy to manufacture. These through conductors 3 are formed by embedding a metal paste similar to that of the conductor layer 2 in a through hole formed by, for example, punching a ceramic green sheet, and then firing the same at the same time as the dielectric substrate 1.
The diameter of the through conductor 3 is suitably 50 to 300 μm.

Next, another embodiment of the dielectric waveguide line according to the present invention is shown in FIG. 3 in a plan view similar to FIG.

According to the structure shown in FIG. 3, the dielectric waveguide line of the present invention has a bent portion in a part of the through conductor group 4 which is the transmission line, and the bent portion has a transmission direction of the high-frequency signal. The through-conductor group 4 is arranged so that the width of the line perpendicular to the line is substantially the same as the constant width d. One row of the through-conductor group 4 located inside the bent portion is similar to FIG. The penetrating conductors 3 are arranged and formed in a polygonal line with one penetrating conductor 7 as a bending point, and the other row of the penetrating conductor group 4 located outside the bent portion has this one penetrating conductor 7 as a vertex. The penetrating conductor 3 is formed in a polygonal shape corresponding to the base 8a of the isosceles triangle 8 having a certain width d and a height.

The example shown in FIG. 3 can be said to have a shape in which the corners of the bent portion are obliquely cut, and the manufacture of the bent portion is easier than the bent portion in the example shown in FIG.

Next, still another example of the embodiment of the dielectric waveguide line of the present invention is shown in FIG. 4 in a plan view similar to FIGS.

According to the structure shown in FIG. 4, the dielectric waveguide line of the present invention has a bent portion in a part of the through conductor group 4 which is the transmission line, and the bent portion has a transmission direction of the high frequency signal. Are arranged such that the width of the line perpendicular to the line is substantially the same as the constant width d. One row of the through conductor group 4 located inside the bent portion is bent in this row. The through conductors 3 are arranged and formed in an arc shape having a predetermined radius r around the inner virtual center point 9, and the other row of the through conductor group 4 located outside the bent portion is positioned at the center. Since the through conductors 3 are arranged and formed in an arc shape having a radius r + d obtained by adding a certain width d to the radius r with the center at the point 9, that is, an arc shape concentric with the inner row, the through conductor group 4 is formed.
Are provided with bent portions arranged in concentric arcs.

The example shown in FIG. 4 has the advantage that the disturbance of the electromagnetic field is very small and the transmission loss is small because both the inside and outside of the bent portion are formed in a smooth shape.

[0039]

EXAMPLE A transmission characteristic of a transmission line including a bent portion of the dielectric waveguide line of the present invention having the structure shown in FIGS. 1 and 2 was calculated by the finite element method. The conductor layer 2 and the through conductor 3 are made of pure copper having a conductivity of 5.8 × 10 ⁷ (1 / Ωm), and the dielectric substrate 1 has a relative permittivity of 5 and a dielectric loss tangent of 0.
Using a glass-ceramic sintered body prepared by firing 75% by weight of borosilicate glass and 25% by weight of alumina of 001,
The thickness a of the dielectric substrate 1 is 1 mm, and the diameter of the through conductor 3 is set to 0.
The frequency characteristics of the S parameters were calculated assuming that 16 mm, the repetition interval p of the through conductor group 4 was 1.58 mm, the fixed width d of the through conductor group 4 was 2 mm (corresponding to the WRJ-34 standard), and the length of the line was 30 mm.

As a result, it was found that the cutoff frequency was about 42 GHz, and that at higher frequencies, the signal was transmitted well. In addition, the electric field distribution at the outlet of the bent portion is similar to that at the inlet, and the bent portion affects the distribution of the electric field strength only in the bent portion, and the distribution of the electric field intensity is outside the transmission line at the bent portion. No electromagnetic wave was emitted at the bent portion.

Further, when a dielectric waveguide line sample having the same configuration was prepared and its transmission characteristics were evaluated, good transmission characteristics similar to the above calculation results were obtained.

Further, the dielectric waveguide of the present invention having the structure shown in FIGS. 3 and 4 was similarly calculated by the finite element method and evaluated the transmission characteristics of the manufactured sample. It was confirmed that there was no electromagnetic wave radiation at the bent portion and that the device had good transmission characteristics.

[0043]

As described above in detail, according to the dielectric waveguide line of the present invention, the dielectric substrate is sandwiched between the pair of conductor layers,
By forming the side wall of the waveguide line with a group of through conductors, it can be easily manufactured by applying the conventional ceramic lamination technology, and regarding the configuration of the bent portion provided in a part of the waveguide line, By forming the penetrating conductor group in two rows in the form of a polygonal line and an arc, or a polygonal line and a polygonal line, or a concentric arc as described above, transmission loss due to radiation and leakage of electromagnetic waves at the bent portion is almost eliminated. As a result, a dielectric waveguide line having good transmission characteristics of a high-frequency signal can be provided.

In particular, the use of ceramics having a high relative dielectric constant for the dielectric substrate makes it suitable for high-density wiring multilayer wiring boards, packages for housing semiconductor elements, and the like, and is stable from the microwave band to the millimeter wave band. A waveguide line having transmission characteristics can be formed.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view for explaining an example of an embodiment of a dielectric waveguide line according to the present invention.

FIG. 2 is a plan view of FIG. 1 for explaining an example of an embodiment of the dielectric waveguide line of the present invention.

FIG. 3 is a plan view similar to FIG. 2 for describing another example of the embodiment of the dielectric waveguide line of the present invention.

FIG. 4 is a plan view similar to FIG. 2 for explaining still another example of the embodiment of the dielectric waveguide line of the present invention.

[Explanation of symbols]

 1 ... dielectric substrate 2 ... conductor layer 3 ... through conductor 4 ... through conductor group 6, 7 ... one through conductor (bending point) 8. .... Isosceles triangle 8a .... Base

Claims (3)

[Claims] A pair of conductor layers sandwiching a dielectric substrate;
In the transmission direction of the high-frequency signal, the cutoff wavelength of the high-frequency signal is 2
Two rows of through conductor groups formed so as to electrically connect the conductor layers with a constant width in a direction orthogonal to the transmission direction at a repetition interval of 1 / th or less, and the conductor layer and A dielectric waveguide line for transmitting a high-frequency signal by a region surrounded by the through conductor group, wherein the two rows of through conductor groups have a bent portion in a part thereof, and Is formed in a polygonal line shape with one through conductor as a bending point, and the other row is formed in an arc shape with the one through conductor as a center and a radius having the constant width. Characteristic dielectric waveguide line. 2. A pair of conductor layers sandwiching a dielectric substrate,
In the transmission direction of the high-frequency signal, the cutoff wavelength of the high-frequency signal is 2
Two rows of through conductor groups formed so as to electrically connect the conductor layers with a constant width in a direction orthogonal to the transmission direction at a repetition interval of 1 / th or less, and the conductor layer and A dielectric waveguide line for transmitting a high-frequency signal by a region surrounded by the through conductor group, wherein the two rows of through conductor groups have a bent portion in a part thereof, and Are formed in a polygonal line shape having one through conductor as a bending point, and the other row corresponds to a base of an isosceles triangle having the bending point of the one row as a vertex and the constant width as a height. A dielectric waveguide line formed in a polygonal line shape. 3. A pair of conductor layers sandwiching a dielectric substrate,
In the transmission direction of the high-frequency signal, the cutoff wavelength of the high-frequency signal is 2
Two rows of through conductor groups formed so as to electrically connect the conductor layers with a constant width in a direction orthogonal to the transmission direction at a repetition interval of 1 / th or less, and the conductor layer and A dielectric waveguide line for transmitting a high-frequency signal by a region surrounded by the through conductor group, wherein the two rows of through conductor groups have a bent portion in which each row is arranged in a concentric arc shape. Characteristic dielectric waveguide line.