JP6685893B2 - Adiabatic waveguide - Google Patents

Description

  Embodiments of the present invention relate to adiabatic waveguides.

Conventionally, there is a waveguide using a planar circuit board as a connection structure for transmitting a signal such as a high frequency between two points having different temperatures. The waveguide may be required to have heat insulation performance.
In the above-mentioned waveguide, the heat inflow can be suppressed and the heat insulation performance can be improved by reducing the area of the ground layer, but in that case, the electromagnetic wave radiation may increase the amount of signal passage loss.

Japanese Patent No. 4236408

  The problem to be solved by the present invention is to provide an adiabatic waveguide that can achieve both low loss and low heat inflow.

  The heat insulating waveguide of the embodiment has a substrate, a first conductor line, a second conductor line and a third conductor line. The first conductor line extends from one end of the substrate to the other end. The second conductor line and the third conductor line are different in position in the thickness direction of the substrate from the first conductor line, and are arranged in the width direction from one end of the substrate to the other end thereof. It is formed separately. The first conductor line is located at a position overlapping at least a part of a gap between the second conductor line and the third conductor line when viewed from a direction perpendicular to the substrate.

(A) The top view which shows one surface of the heat insulation waveguide of embodiment. (B) The top view which shows the other surface of the heat insulation waveguide of embodiment. It is sectional drawing of the heat insulation waveguide of embodiment, and is a figure which shows the II cross section of Fig.1 (a). (A) The top view which shows one surface of the 1st modification of the heat insulation waveguide of embodiment. (B) The top view which shows the other surface of the 1st modification of the heat insulation waveguide of embodiment. It is sectional drawing of the heat insulation waveguide of the 1st modification, Comprising: It is a figure which shows the II-II cross section of Fig.3 (a). (A) The top view which shows one surface of the 2nd modification of the heat insulation waveguide of embodiment. (B) The top view which shows the other surface of the 2nd modification of the heat insulation waveguide of embodiment. The figure which shows typically the heat insulation waveguide of the 3rd modification of the heat insulation waveguide of embodiment. The figure which shows the relationship between the heat inflow amount and the loss amount. The figure which shows the relationship of the ratio of the gap of a ground line with respect to the width of a transmission line, and the amount of losses. (A) The figure which shows the distribution of the electric current intensity in the one surface of the 1st example of an adiabatic waveguide. (B) The figure which shows the distribution of the electric current intensity in the other surface of the 1st example of an adiabatic waveguide. (A) The figure which shows the distribution of the electric current intensity in the one surface of the 2nd example of an adiabatic waveguide. (B) The figure which shows the distribution of the electric current intensity in the other surface of the 2nd example of an adiabatic waveguide. (A) The figure which shows the distribution of the electric current intensity in one surface of the other example of a heat insulation waveguide. (B) The figure which shows the distribution of the electric current intensity in the other surface of the other example of a heat insulation waveguide. (A) The top view which shows one surface of an example of the conventional heat insulation waveguide. (B) The top view which shows the other surface of an example of the conventional heat insulation waveguide.

  Hereinafter, the heat insulating waveguide of the embodiment will be described with reference to the drawings.

  FIG. 1A is a plan view showing one surface of the heat insulating waveguide 100 of the embodiment. FIG. 1B is a plan view showing the other surface of the heat insulating waveguide 100 of the embodiment. FIG. 2 is a cross-sectional view of the adiabatic waveguide 100 and is a view showing a II cross section of FIG. Note that the plan view refers to viewing from a direction perpendicular to the dielectric substrate 101.

  As shown in FIGS. 1A and 1B, the heat insulation waveguide 100 includes a dielectric substrate 101, a transmission line 102, a first ground line 103a, and a second ground line 103b. .

The dielectric substrate 101 is made of, for example, a ceramic material such as alumina. The dielectric substrate 101 is, for example, rectangular in plan view. The dielectric substrate 101 is an example of a “substrate”.
The direction along the length direction of the dielectric substrate 101 is called the Y direction. The direction orthogonal to the Y direction in the plane along the first main surface 101a of the dielectric substrate 101 is called the X direction.

  The heat insulating waveguide 100 can be used, for example, in an environment in which one end 104a in the length direction of the dielectric substrate 101 has a higher temperature than the other end 104b. That is, for example, the end portion 104a is arranged on the high temperature portion side, and the end portion 104b is arranged on the low temperature portion side. The end 104a may be referred to as a high temperature end 104a, and the end 104b may be referred to as a low temperature end 104b. The temperature difference between one end (high temperature end 104a) and the other end (low temperature end 104b) of the heat insulating waveguide 100 is, for example, 150 ° C. or more.

  As shown in FIGS. 1A and 2, the transmission line 102 is formed on the first main surface 101 a (one surface) of the dielectric substrate 101. The transmission line 102 is a film made of a conductive material such as metal. As the metal, for example, gold, copper, copper alloy or the like is preferable. The transmission line 102 is an example of a “first conductor line”.

  The transmission line 102 is formed from the high temperature end 104a to the low temperature end 104b of the dielectric substrate 101. The transmission line 102 is formed, for example, in the center of the dielectric substrate 101 in the width direction (X direction) along the length direction (Y direction) of the dielectric substrate 101 and has a constant width in the length direction. The width of the transmission line 102 (that is, the dimension in the X direction) is referred to as “width W”.

The transmission line 102 is located at a position overlapping a gap 105 between the ground lines 103a and 103b, which will be described later, in plan view.
Note that the transmission line 102 shown in FIGS. 1A and 2 and the like is located at a position where it is entirely overlapped with the gap 105, but the transmission line may be located at a position where it is at least partially overlapped with the gap.

As shown in FIGS. 1B and 2, the first ground line 103a and the second ground line 103b are formed on the second main surface 101b (the other surface) of the dielectric substrate 101. The first ground line 103a and the second ground line 103b are films made of a conductive material such as metal. As the metal, for example, gold, copper, copper alloy or the like is preferable.
The first ground line 103a is an example of a "second conductor line". The second ground line 103b is an example of a “third conductor line”.

  The first ground line 103a and the second ground line 103b are respectively formed from the high temperature end 104a to the low temperature end 104b of the dielectric substrate 101. The first ground line 103a and the second ground line 103b have, for example, a constant line width, and are formed along the length direction (Y direction) of the dielectric substrate 101. The width directions of the first ground line 103a and the second ground line 103b coincide with the X direction.

The first ground line 103a and the second ground line 103b are formed apart from each other in the width direction (X direction) of the lines 103a and 103b. The first ground line 103a and the second ground line 103b are parallel to each other and are formed in parallel on the second main surface 101b of the dielectric substrate 101.
The first ground line 103a and the second ground line 103b need only be formed along substantially the same direction, and need not be parallel to each other. For example, if both the first ground line and the second ground line are formed by connecting one end and the other end of the substrate, it can be said that they are formed substantially in the same direction.

  Since the first ground line 103a and the second ground line 103b are formed on the second main surface 101b of the dielectric substrate 101, the transmission line 102 formed on the first main surface 101a is different from that of the dielectric substrate 101. The position in the thickness direction is different.

  The gap 105 between the first ground line 103a and the second ground line 103b is a region of the second main surface 101b between the first ground line 103a and the second ground line 103b. The gap 105 is a rectangular area extending from the high temperature end 104a to the low temperature end 104b of the dielectric substrate 101. The gap 105 has a constant width in the length direction (X direction), for example. The dimension of the gap 105 in the width direction (dimension in the X direction) is referred to as “gap G”.

The first ground line 103a and the second ground line 103b are, for example, parallel to the transmission line 102. The width of the first ground line 103a and the width of the second ground line 103b may be the same as or different from each other.
The first ground line 103a and the second ground line 103b need only be formed along the same direction as the transmission line 102, and need not be parallel to the transmission line 102. For example, if the ground line and the transmission line are both formed by connecting one end and the other end of the substrate, the ground line is formed substantially in the same direction as the transmission line. Can be said.

As shown in FIG. 2, the inner side edges 103a1 and 103b1 (the opposite edges) of the first ground line 103a and the second ground line 103b are more outward than the side edges 102a and 102a of the transmission line 102, for example. It is located close to. That is, the inner side edge 103a1 of the ground line 103a is located closer to the −X direction than the side edge 102a1 of the transmission line 102 on the −X direction side. An inner side edge 103b1 of the ground line 103b is located closer to the + X direction than a side edge 102a2 of the transmission line 102 on the + X direction side.
The + X direction is a direction of the X direction from the first ground line 103a toward the second ground line 103b. The −X direction is the opposite direction of the + X direction.

The distance L1 between the first ground line 103a and the transmission line 102 in the width direction (X direction) and the distance L2 between the second ground line 103b and the transmission line 102 in the width direction (X direction) are preferably equal to each other. .
The distance L1 is a distance in the X direction between the inner side edge 103a1 of the first ground line 103a and the −X direction side side edge 102a1 of the transmission line 102. The distance L2 is a distance in the X direction between the inner side edge 103b1 of the second ground line 103b and the side edge 102a2 of the transmission line 102 on the + X direction side.

According to the adiabatic waveguide 100 shown in FIGS. 1A, 1B, and 2, the transmission line 102 is located at a position overlapping the gap 105 between the first ground line 103a and the second ground line 103b. Therefore, as compared with the case where the entire transmission line overlaps with the ground line, the loss can be suppressed low even when the area of the line is small.
By reducing the areas of the transmission line 102 and the ground lines 103a and 103b, the amount of heat inflow can be suppressed, so that in the adiabatic waveguide 100, the loss can be reduced and the heat inflow can be suppressed. That is, the heat insulating waveguide 100 can achieve both low loss and low heat inflow.

In the heat insulating waveguide 100, the following assumption can be made regarding the fact that the loss can be suppressed even when the area of the line is small.
In the heat insulating waveguide 100, the transmission line 102 is located at a position overlapping the gap 105 between the ground lines 103a and 103b. Therefore, the radiation of energy in the transmission line 102 and the ground lines 103a and 103b is suppressed by the bias of the current distribution at the side edge of the line due to the electrical interaction between the transmission line 102 and the ground lines 103a and 103b. Therefore, as compared with the case where the entire transmission line overlaps with the ground line, the loss can be suppressed even when the area of the line is small.

  In the adiabatic waveguide 100, since the transmission line 102 and the ground lines 103a and 103b have no defective portions, it is advantageous when a direct current is used. Therefore, it is possible to deal with the supply of the direct current to the circuit connected to the downstream side.

Next, a first modified example of the heat insulating waveguide 100 of the embodiment will be described. The same points as those of the heat insulating waveguide 100 are designated by the same reference numerals, and the description thereof will be omitted.
FIG. 3A is a plan view showing one surface of a heat insulating waveguide 100A which is a first modified example of the heat insulating waveguide 100. FIG. 3B is a plan view showing the other surface of the heat insulating waveguide 100A. FIG. 4 is a cross-sectional view of the heat insulating waveguide 100A and is a view showing a II-II cross section of FIG.

As shown in FIG. 3A, FIG. 3B, and FIG. 4, the adiabatic waveguide 100A is the same as that shown in FIG. 1A except that the cutout 504 is formed in the intermediate portion 102d of the transmission line 102. The heat insulating waveguide 100 shown in FIGS. 1B and 2 has the same structure.
The intermediate portion 102d is a portion between the one end portion 102b and the other end portion 102c of the transmission line 102.

The defective portion 504 is a portion where there is no conductive film forming the transmission line 102. In the defective portion 504, the first main surface 101a of the dielectric substrate 101 is exposed.
The defective portion 504 is located, for example, inside the side edges 102a and 102a of the transmission line 102. That is, as shown in FIG. 4, the defective portion 504 is located closer to the + X direction than the side edge 102a1 of the transmission line 102 and closer to the −X direction than the side edge 102a2.

  As shown in FIG. 3A, the defective portion 504 is formed, for example, in the center of the transmission line 102 in the width direction (X direction) along the length direction (Y direction) of the transmission line 102. The defective portion 504 has, for example, a constant width in the length direction. The planar view shape of the defective portion 504 is, for example, a rectangular shape (for example, a rectangle). The plan view shape of the defective portion is not particularly limited, and may be, for example, an elliptical shape with the major axis direction oriented in the length direction of the line.

  In the adiabatic waveguide 100A, since the defective portion 504 is formed in the intermediate portion 102d having a low current intensity, the area of the transmission line 102 can be reduced without increasing the loss. Therefore, it is possible to reduce the loss and further suppress the heat inflow amount.

Next, a second modified example of the heat insulating waveguide 100 of the embodiment will be described. The same points as those of the heat insulating waveguide 100 are designated by the same reference numerals, and the description thereof will be omitted.
FIG. 5A is a plan view showing one surface of a heat insulating waveguide 100B which is a second modified example of the heat insulating waveguide 100. FIG. 5B is a plan view showing the other surface of the heat insulating waveguide 100B.

As shown in FIGS. 5A and 5B, in the heat insulating waveguide 100B, a narrow portion having a narrower width than the other portion 804a in the length direction of the transmission line 802 is provided in the middle portion 802d of the transmission line 802. The structure is the same as that of the adiabatic waveguide 100 shown in FIG. 1A, FIG. 1B, and FIG. 2 except that 804b is formed.
The intermediate portion 802d is a portion between the one end 802b and the other end 802c of the transmission line 802.
The narrow portion 804b is formed by forming a notch in each of the side edges 802a, 802a. The narrow portion 804b has, for example, a constant width in the length direction.
The narrow portion 804b is formed by forming notches having the same width on both side edges 802a, 802a. Therefore, the position of the narrow portion 804b in the width direction (X direction) is the center of the transmission line 802.

  In the adiabatic waveguide 100B, since the narrow portion 804b is formed in the intermediate portion 802d having a low current intensity, the area of the transmission line 802 can be reduced without increasing loss. Therefore, it is possible to reduce the loss and further suppress the heat inflow amount.

Next, a third modified example of the heat insulating waveguide 100 of the embodiment will be described. The same points as those of the heat insulating waveguide 100 are designated by the same reference numerals, and the description thereof will be omitted.
FIG. 6 is a diagram schematically showing a heat insulating waveguide 100C which is a third modified example of the heat insulating waveguide 100.

As shown in FIG. 6, the heat insulating waveguide 100C has the same configuration as that of the heat insulating waveguide 100 shown in FIGS. 1A, 1B and 2, except that the substrate 1001 is a flexible substrate.
The substrate 1001 is a flexible substrate made of, for example, a polyimide material.
Connection parts 1004a and 1004b are provided at both ends of the heat insulating waveguide 100C, respectively.
The heat insulating waveguide 100C is bent at about 90 ° in the thickness direction at the bent portion 1003, for example.

  In the heat insulating waveguide 100C, since the substrate 1001 is a flexible substrate, bending deformation in the thickness direction is possible. Therefore, the degree of freedom in mounting can be increased without increasing loss. Therefore, even if the connection parts 1004a and 1004b have restrictions on the installation position, they can be installed at appropriate positions. Therefore, it is possible to reduce the size of the device using the heat insulating waveguide 100C.

  Hereinafter, the above-described embodiment will be described in more detail based on examples.

First, the first embodiment will be described.
Using the adiabatic waveguide 100 shown in FIGS. 1A, 1B and 2, the loss amount (dB) and the heat inflow amount (mW) when the center frequency was 9 GHz were calculated.
The thermal conductivity of the dielectric substrate 101 of the heat insulating waveguide 100 was 0.5 (W / m · K), the thickness was 0.1 mm, and the width was 2 mm.
The thickness of the metal film forming the transmission line 102 and the ground lines 103a and 103b was 9 μm. The metal forming the metal film was copper. The width of the transmission line 102 was 0.24 mm (50Ω line width in the microstrip line). The total width of the ground lines 103a and 103b is 0.2 mm.
In this configuration, the loss amount at the center frequency is 0.32 dB and the heat inflow amount is 31.7 mW. The results are shown in Fig. 7.

Next, Comparative Example 1 will be described.
FIG. 12A is a plan view showing one surface of a heat insulating waveguide 200 which is an example of a conventional heat insulating waveguide. FIG. 12B is a plan view showing the other surface of the heat insulating waveguide 200.
The heat insulating waveguide 200 includes a dielectric substrate 201, a transmission line 202, and a ground line 203.
The transmission line 202 is formed on the first main surface 201a (one surface) of the dielectric substrate 201. The transmission line 202 is located at a position overlapping the ground line 203 in a plan view.
The ground line 203 is formed on the second main surface 201b (the other surface) of the dielectric substrate 201. The ground line 203 is formed wider than the transmission line 202. The center line along the length direction of the ground line 203 overlaps the center line along the length direction of the transmission line 202 in a plan view.

Using the adiabatic waveguide 200 shown in FIGS. 12A and 12B, the loss amount (dB) and the heat inflow amount (mW) when the center frequency was 9 GHz were calculated.
The thermal conductivity of the dielectric substrate 201 of the heat insulating waveguide 200 was 0.5 (W / m · K), the thickness was 0.1 mm, and the width was 2 mm.
The thickness of the metal film forming the transmission line 202 and the ground line 203 was 9 μm. The metal forming the metal film was copper. The width of the transmission line 202 was 0.24 mm (50Ω line width in the microstrip line).
When the width W1 of the ground line 203 is 0.2 mm, 0.75 mm, and 1.2 mm, the loss amounts at the center frequency are 0.50 dB, 0.26 dB, and 0.18 dB, respectively. The heat inflows are 31.7 mW, 47.3 mW, and 70.5 mW, respectively. The results are shown in Fig. 7.

Next, Comparative Example 2 will be described.
The loss amount (dB) and the heat inflow amount (mW) when the center frequency was set to 9 GHz were calculated using a waveguide which is a coaxial cable.
The outer diameter of the central conductor (Cu) of the waveguide was set to 2.2 mm. The outer diameter of the intermediate layer (Cu) was 3.2 mm. The outer diameter of the outermost layer (CuNi) was set to 3.6 mm.
The loss amounts at the center frequency are 1.60 dB, 0.42 dB, and 0.25 dB, respectively. The heat inflows are 78 mW, 357 mW and 714 mW, respectively. The results are shown in Fig. 7.

As shown in FIG. 7, in Example 1, a lower heat inflow amount can be achieved with a comparable loss amount, and a lower loss amount can be achieved with a comparable heat inflow amount, as compared with Comparative Examples 1 and 2.
From this, it can be seen that in the first embodiment, since the loss can be suppressed by reducing the line area that causes heat inflow, both the low loss amount and the low heat inflow amount can be achieved.
Further, in the first embodiment, since there is no defective portion in the line, it is advantageous when a direct current is used. Therefore, it is possible to deal with the supply of the direct current to the circuit connected to the downstream side.

  In the heat insulating waveguide 100 according to the first embodiment, the width W of the transmission line 102 (see FIG. 1A and FIG. 2) is constant, and the gap G between the ground lines 103a and 103b (see FIG. 1B and FIG. 2). ) Was changed, the ratio of the gap G to the width W (G / W) was calculated. FIG. 8 shows the calculation result of the relationship between the ratio G / W and the loss amount. The center line of the transmission line 102 in the width direction and the center line of the gap 105 in the width direction were made to coincide with each other in a plan view.

From FIG. 8, the loss amount can be reduced by setting the ratio G / W to be larger than 1.
As the ratio G / W increases up to a certain range, the bias of the current intensity decreases, but if it becomes too large, the radiation loss may increase. Therefore, the loss amount as a whole may increase.
By setting the ratio G / W to 2 or more, the loss amount can be further reduced. By setting the ratio G / W to 3.5 or less, the total loss amount can be reduced. Therefore, the loss amount can be reduced by setting the ratio G / W to 2 to 3.5.

Next, a second embodiment will be described.
Using the adiabatic waveguide 100A shown in FIGS. 3A, 3B, and 4, the loss amount (dB) and the heat inflow amount (mW) when the center frequency was 9 GHz were calculated.
The second embodiment is similar to the first embodiment except that the defective portion 504 is formed at the center of the transmission line 102 in the width direction.
Table 1 shows the calculation results of the loss amount and the heat inflow amount at the center frequency in this configuration.

  From Table 1, it can be seen that in Example 2, the heat inflow amount can be lowered without increasing the loss amount as compared with Example 1.

Next, a third embodiment will be described.
Using the adiabatic waveguide 100B shown in FIGS. 5A and 5B, the loss amount (dB) and the heat inflow amount (mW) when the center frequency was 9 GHz were calculated.
The third embodiment is similar to the first embodiment except that the narrow portion 804b is formed in the intermediate portion 802d of the transmission line 802.
Table 2 shows the calculation results of the loss amount and the heat inflow amount at the center frequency in this configuration.

  From Table 2, it can be seen that in Example 3, the heat inflow amount can be reduced without increasing the loss amount as compared with Example 1.

Next, a fourth embodiment will be described.
Using the adiabatic waveguide 100C shown in FIG. 6, the loss amount (dB) was calculated when the center frequency was 9 GHz.
Example 3 was the same as Example 1 except that the flexible substrate 1001 was used as the substrate.
In this configuration, Table 3 shows the loss amount at the center frequency when the heat insulating waveguide 100C is bent by 90 ° in the thickness direction and when it is not bent (bending angle 0 °).

  From Table 3, it can be seen that in Example 4, even when bending is applied, the same loss amount as when bending is not applied is obtained.

  FIG. 9A is a diagram showing a distribution of current intensity on one surface (first main surface 101a) of the heat insulating waveguide 100D which is the first example of the heat insulating waveguide 100. FIG. 9B is a diagram showing a distribution of current intensity on the other surface (second main surface 101b) of the heat insulating waveguide 100D. In FIG. 9 (a) and FIG. 9 (b), the current intensity is represented by shading.

As shown in FIG. 9B, in the heat insulating waveguide 100D, the gap G (G1) between the ground lines 103a and 103b is relatively small. Therefore, the distance between the ground lines 103a and 103b and the transmission line 102 is small.
As shown in FIG. 9A, the current intensity is high in the portions of the side edges 102a, 102a of the transmission line 102 near the ends 102b, 102c.
As shown in FIG. 9B, in the inner side edges 103a1, 103b1 of the ground lines 103a, 103b (edges on the opposite sides), the current strength is close to the end portions 103a2, 103a3, 103b2, 103b3. It's getting higher.

  FIG. 10A is a diagram showing a distribution of current intensity on one surface (the first main surface 101a) in the heat insulating waveguide 100E which is the second example of the heat insulating waveguide 100. FIG.10 (b) is a figure which shows distribution of the electric current intensity in the other surface (2nd main surface 101b) in the heat insulation waveguide 100E.

As shown in FIG. 10B, in the heat insulating waveguide 100E, the gap G (G2) between the ground lines 103a and 103b is relatively large. Therefore, the distance between the ground lines 103a and 103b and the transmission line 102 is larger than that of the adiabatic waveguide 100D shown in FIGS. 9A and 9B.
As shown in FIG. 10A, the current intensity is higher in the portions of the side edges 102a and 102a of the transmission line 102 closer to the ends 102b and 102c than in the other portions. Compared with the transmission line 102 of the adiabatic waveguide 100D shown, the deviation of the current intensity is small.
As shown in FIG. 10B, the current densities are different at the inner side edges 103a1 and 103b1 of the ground lines 103a and 103b (the edges on the opposite sides) which are close to the end portions 103a2, 103a3, 103b2 and 103b3. Although it is higher than that of the portion, the bias of the current density is smaller than that of the ground lines 103a and 103b of the adiabatic waveguide 100D shown in FIG. 9B.

  FIG. 11A is a diagram showing a distribution of current density on one surface (first main surface 101a) of a heat insulating waveguide 100F which is another example of the heat insulating waveguide. FIG. 11B is a diagram showing the distribution of the current density on the other surface (second main surface 101b) of the heat insulating waveguide 100F.

  The heat insulating waveguide 100F is an example in which the gap G between the ground lines 103a and 103b shown in FIGS. 9B and 10B is zero. Therefore, as shown in FIG. 11B, one ground line 103ab is formed on the second main surface 101b of the dielectric substrate 101 instead of the ground lines 103a and 103b.

As shown in FIGS. 9 (a) to 11 (b), the heat insulating waveguides 100D and 100E shown in FIGS. 9 (a) to 10 (b) are shown in FIGS. 11 (a) and 11 (b). The distribution of current density in the transmission line and the ground line is different from that of the adiabatic waveguide 100F.
In addition, compared with the adiabatic waveguide 100D (see FIGS. 9A and 9B), the adiabatic waveguide 100E (see FIGS. 10A and 10B) having a larger gap G has a higher current density. The bias of is relatively small.

In the adiabatic waveguide 100 shown in FIG. 1A, FIG. 1B, and FIG. 2, the entire transmission line 102 overlaps the gap 105 in a plan view, but a part of the transmission line 102 is grounded. It may overlap with the lines 103a and 103b.
In the adiabatic waveguide 100, as shown in FIG. 2, the distance L1 between the first ground line 103a and the transmission line 102 and the distance L2 between the second ground line 103b and the transmission line 102 are equal to each other, but the distance L1 is equal to the distance L1. The distance L2 does not have to be the same.
In the adiabatic waveguide 100, the transmission line 102, the first ground line 103a, and the second ground line 103b are parallel to each other, but the present invention is not limited to this, and the lines 102, 103a, and 103b have two or more of them. The tracks do not have to be parallel.

  The adiabatic waveguide 100 has two ground lines 103a and 103b, but the number of ground lines may be plural, and for example, three or more ground lines may be formed at intervals in the width direction. Good. In that case, the adiabatic waveguide has a plurality of gaps between the ground lines, but the transmission line only needs to be in a position overlapping at least a part of at least one of the plurality of gaps.

  In the heat insulating waveguide 100, the transmission line 102 and the ground lines 103a and 103b are formed on one surface and the other surface of the dielectric substrate 101, respectively. As a result, the transmission line 102 and the ground lines 103a and 103b are formed at different positions in the thickness direction of the dielectric substrate 101. In the heat insulating waveguide of the embodiment, the configuration in which the transmission line and the ground line are formed at different positions in the thickness direction of the substrate is not limited to this. For example, one of the transmission line and the ground line may be formed on the surface of the substrate and the other may be embedded inside the substrate.

  In the adiabatic waveguide 100 shown in FIG. 2, the inner side edges 103a1 and 103b1 of the ground lines 103a and 103b are more outward than the side edges 102a and 102a of the transmission line 102 over the entire length in the width direction (X direction). However, only a part of the side edges 103a1 and 103b1 in the length direction may be located outward of the side edges 102a and 102a of the transmission line 102.

  The side edges 103a1 and 103b1 of the ground lines 103a and 103b are preferably located outwardly of the side edges 102a and 102a of the transmission line 102 in a plan view, but they are located at positions corresponding to the side edges 102a and 102a. Alternatively, it may be located inward of the side edges 102a, 102a.

In the heat insulating waveguide 100A shown in FIGS. 3A, 3B and 4, the defective portion 504 is formed only in the transmission line 102 of the transmission line 102 and the ground lines 103a and 103b. The adiabatic waveguide according to the embodiment is not limited to this, and may have a configuration in which a defective portion is formed in at least one of the transmission line and the ground line. For example, a defect portion may be formed in either or both of the first ground line and the second ground line.
In the adiabatic waveguide 100A, the position of the defective portion 504 in the width direction (X direction) is the center of the transmission line 102, but the position of the defective portion in the transmission line in the width direction is not limited to this, and is X with respect to the center. The position may be shifted in the direction.

In the heat insulating waveguide 100B shown in FIGS. 5A and 5B, the narrow portion 804b is formed only in the transmission line 802 of the transmission line 802 and the ground lines 103a and 103b. The adiabatic waveguide of the embodiment is not limited to this, and may have a configuration in which the narrow portion is formed in at least one of the transmission line and the ground line. For example, the narrow portion may be formed in either or both of the first ground line and the second ground line.
In the adiabatic waveguide 100B, the position of the narrow portion 804b in the width direction (X direction) is the center of the transmission line 802, but the position of the narrow portion in the transmission line in the width direction is not limited to this, and the position in the center is May be displaced in the X direction.

  According to at least one embodiment described above, since the transmission line 102 is located at a position overlapping the gap 105 between the first ground line 103a and the second ground line 103b, it is possible to reduce loss and suppress heat inflow. .

  Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the invention described in the claims and the equivalents thereof as well as included in the scope and the gist of the invention.

100, 100A, 100B, 100C ... Adiabatic waveguide, 101 ... Dielectric substrate, 102 ... Transmission line, 102d, 802d ... Intermediate part, 103a ... First ground line 103a (second conductor line), 103b ... Second ground line 103b (third conductor line), 104a ... End part (one end part), 104b ... End part (other end part), 105 ... Gap, 804b ... Narrow part, 1001 ... Flexible substrate.

Claims (5)

Board,
A first conductor line extending from one end to the other end of the substrate;
A second conductor line and a third conductor line that are formed at different positions in the thickness direction of the substrate from the first conductor line and are separated from each other in the width direction from one end of the substrate to the other end thereof. And a conductor line,
Said first conductor line, when viewed from a direction perpendicular to the substrate, Ri position near overlapping with at least a portion of the gap between the second conductor line and the third conductor line,
The first conductor line is an adiabatic waveguide having a cutout portion at an intermediate portion between the one end portion and the other end portion .   The heat insulating waveguide according to claim 1, wherein a gap between the second conductor line and the third conductor line is wider than a width of the first conductor line.   The heat insulating waveguide according to claim 2, wherein a ratio G / W of a gap G between the second conductor line and the third conductor line and a width W of the first conductor line is 2 to 3.5. At least one of the first conductor line, the second conductor line, and the third conductor line has a width that is narrower than at least a part of the other portion of the conductor line whose position in the length direction is different. having a narrow section, adiabatic waveguide according to any one of claims 1-3. The substrate is a flexible substrate, insulation waveguide according to any one of claims 1-4.