JP4867359B2 - Transmission line interlayer connection structure - Google Patents

Description

  The present invention relates to a transmission line interlayer connection structure used for transmission and reception in the millimeter wave band.

  In order to use the dielectric waveguide line in the multilayer wiring board as a transmission line for millimeter waves, it is necessary to electrically connect the layers. One of the methods for realizing such electrical connection is a method of connecting the upper and lower triplate lines with patches formed at the end of the line (see, for example, Patent Document 1), and around the through hole for interlayer connection In addition, there is a method of forming a via hole group having a periodic structure or a via hole group having a coaxial structure (see, for example, Patent Document 2).

  In Patent Document 1, referring to FIG. 1, the first ground conductor 1 / the first dielectric 4a / the first power supply board 6 / the second dielectric 4b / the second ground conductor 2 is used. The first triplate line and the second triplate line composed of the second ground conductor 2 / the third dielectric 7a / the second power supply substrate 9 / the fourth dielectric 7b / the third ground conductor 3. In particular, there is shown a connector for electrically connecting to each other, and in particular, a patch pattern is formed at a connection terminal portion of each feed line, and these patch patterns are electromagnetically coupled to each other at a frequency to be used. is there.

In Patent Document 2, a periodic structure via hole group or a coaxial structure via hole group is formed around a via hole serving as a central conductor to confine electromagnetic waves in a plane direction, thereby performing interlayer connection with a small loss.
JP 11-261308 A JP 2003-133801 A

  However, in the method described in Patent Document 1, it is necessary to form a hollow structure between the upper and lower patches, and there are problems that the manufacturing process is complicated, the cost is high, and the plate thickness is increased.

  In the method described in Patent Document 2, high-frequency signal leakage is prevented by the periodic structure of the via holes, but the connection between layers goes through through holes with unstable characteristic impedance. There was a problem that it was insufficient for loss reduction.

  The present invention is a method proposed to solve the above problems, and an object of the present invention is to provide a transmission line interlayer connection structure that is thin and has low transmission loss.

In order to achieve the above object, the transmission line interlayer connection structure according to claim 1 is configured such that the first ground conductor pattern having the same potential as the ground conductor layer is connected to the terminal portion of the first feed line. A first transmission line configured by laminating a conductor layer, a first dielectric layer, a first ground conductor layer in which a first slot is formed, and a second dielectric layer; A second conductor layer in which a second ground conductor pattern having the same potential as that of the ground conductor layer is connected to the terminal portion of the second feeder line, a third dielectric layer, and a second slot are formed. And a second transmission line configured by laminating a second ground conductor layer, the first conductor layer, the first ground conductor layer, the second ground conductor layer, and the second ground line. The first ground conductor pattern and the first ground conductor are formed on the transmission line layer in which the layers are laminated and integrated in the order of the conductor layers. A layer, the second ground conductor layer, between the second ground conductor pattern, and electrically connected by a via hole group formed around the said first slot and said second slot, The length of the first slot in the direction parallel to the first feed line and the length in the direction perpendicular to the first feed line are at least 0.5 times the effective line wavelength of the frequency to be used, The length of the second slot in the direction parallel to the second feed line and the length in the direction perpendicular to the second feed line are at least 0.5 times the effective line wavelength of the frequency used, The interval between the via hole groups is equal to or less than one-fourth of the effective line wavelength of the frequency to be used, the connection between the first feed line and the first ground conductor pattern, and the second feed line. A slit is formed in each of the connecting portions with the second ground conductor pattern. And summarized in that it was.

The transmission line interlayer connection structure according to claim 2 is the transmission line interlayer connection structure according to claim 1 , wherein the second ground conductor layer and the third dielectric layer are not provided, and the first conductor layer is provided. The first dielectric layer, the first ground conductor layer, the second dielectric layer, and the second conductor layer are laminated and integrated in this order.

The transmission line interlayer connection structure according to claim 3 is the transmission line interlayer connection structure according to claim 1 or 2 , wherein the structure of the first transmission line and the second transmission line is a microstrip line or a strip. The gist is that it is an arbitrary structure of a line and a coplanar line.

  According to the first aspect of the present invention, the first ground conductor pattern formed in the first conductor layer, the first slot formed in the first ground conductor layer, and the first ground conductor. A first cavity structure is formed by a via hole group for electrically connecting the pattern and the first ground conductor layer.

  Similarly, a second ground conductor pattern formed in the second ground conductor layer, a second slot formed in the second ground conductor layer, the second ground conductor pattern and the second ground conductor. A second cavity structure is formed by a group of via holes for electrically connecting the conductor layers.

  A high-frequency signal flowing through the first transmission line resonates in the first cavity structure, and similarly, a high-frequency signal flowing through the second transmission line resonates in the second cavity structure. At this time, the first cavity structure and the second cavity structure are electromagnetically coupled to each other via the first slot and the second slot, whereby the interlayer connection of the transmission line can be achieved. For this reason, unlike the hollow structure described in Patent Document 1, an inexpensive and thin transmission line interlayer connection structure is obtained.

  In addition, it is possible to perform interlayer connection with a waveguide structure having a transmission loss smaller than that in Patent Document 2.

Further, according to the invention described in claim 1, it is possible to adjust the resonance peak frequency of the reflection loss by slits length, at a desired frequency, it is possible to inter-connect lower loss.

Further, according to the invention described in claim 1, electromagnetic waves can be suppressed parallel plate components, it is possible to inter-connect lower loss.

Further, according to the invention described in claim 2 , in addition to the effect of the invention described in claim 1, it is possible to configure an odd-numbered layer such as a three-layer structure, and to further reduce the thickness.

Furthermore, according to the invention described in claim 3 , in addition to the effect of the invention described in claim 1 or 2 , it is possible to connect transmission line structures of arbitrary forms between layers, and the degree of freedom in substrate design is increased. improves.

  Hereinafter, embodiments of a transmission line interlayer connection structure according to the present invention will be described in detail with reference to the drawings.

<First Embodiment>
FIG. 1 is an exploded perspective view showing a schematic configuration of a first embodiment of a transmission line interlayer connection structure in the present invention.

As shown in FIG. 1, the transmission line interlayer connection structure 100 according to the first embodiment of the present invention includes a second conductor layer 3B, a third dielectric layer 1 C , a second ground conductor layer 2B, The second dielectric layer 1 B , the first ground conductor layer 2 A, the first dielectric layer 1 A, and the first conductor layer 3 A are laminated in this order from the bottom.

  Here, a first feed line 4A and a second feed line 4B are formed in the first conductor layer 3A and the second conductor layer 3B, respectively, and ground conductor patterns 5A and 5B is connected. At this time, a slit may be formed in the connecting portion as will be described later according to the required characteristics.

  In addition, the first ground conductor layer 2A and the second ground conductor layer 2B have positions corresponding to the ground conductor patterns 5A and 5B formed on the first conductor layer 3A and the second conductor layer 3B, respectively. Slots 6A and 6B are formed. The slots 6A and 6B serve as a window for electromagnetic wave passage between the ground conductor pattern 5A and the ground conductor pattern 5B.

  Further, particularly in the present invention, the via hole group 10 for electrically connecting the ground conductor pattern 5A, the first ground conductor layer 2A, the second ground conductor layer 2B, and the ground conductor pattern 5B, It is characterized by being regularly formed at positions corresponding to the periphery of the slots 6A and 6B.

  FIG. 2 is a plan view of the conductor layer 3A (3B). Specifically, in the conductor layer 3A (3B), a ground conductor pattern 5A (5B) having the same potential as that of the ground conductor layer is connected to a terminal portion of the feeder line 4A (4B), and a resonance peak of reflection loss is connected to the connection portion. Slits 7A (7B) for adjusting the frequency are formed.

  The ground conductor pattern 5A (5B) is electrically connected to the ground conductor layer 2A (2B) at a position corresponding to the periphery of the slot 6A (6B) formed in the ground conductor layer 2A (2B). A via hole group 10 is formed.

  It is preferable that the interval between the via hole groups is set to be equal to or less than ¼ of the effective line wavelength of the frequency to be used. This is because the parallel plate component of the electromagnetic wave increases and the transmission loss increases as a result of the interval between the via hole groups being equal to or greater than one quarter of the line effective wavelength.

  FIG. 3 is a plan view of a modified example of the conductor layer 3A (3B). As described above, the connection portion between the feed line 4A (4B) and the ground conductor pattern may not be formed with a slit according to the required characteristics.

  FIG. 4 is a plan view of the ground conductor layer 2A (2B). The length L1 of the slot 6A (6B) formed in the ground conductor layer 2A (2B) in the feed line direction and the length L2 in the direction perpendicular thereto are preferably 0.5 times or more of the effective line wavelength of the frequency used. . This is because when L1 and L2 are less than 0.5 times the effective line wavelength used, the electromagnetic wave radiated from the cavity structure is prevented from passing, resulting in an increase in transmission loss.

  The via hole group 11 connecting the ground conductor layers is preferably formed so as to go around the slot 6A (6B).

  In general, two ground conductor layers 2A and 2B are used as in the first embodiment described above. However, as shown in FIG. 5, the second ground conductor layer 2B is removed and the first ground conductor is removed. The layer 2A may be a common ground conductor layer for the first conductor layer 3A and the second conductor layer 3B. According to such a configuration, an odd-numbered layer structure such as a three-layer structure is possible, and the thickness can be further reduced.

<Second Embodiment>
FIG. 6 is an exploded perspective view showing a schematic configuration of the second embodiment of the transmission line interlayer connection structure in the present invention.

  In the first embodiment, the transmission line interlayer connection structure for connecting the microstrip lines to each other has been described. However, in the second embodiment, the transmission line interlayer connection structure of the present invention is replaced with a microstrip line and a strip. It was applied to the connection with the track. In addition, the same code | symbol is attached | subjected to the same structure as 1st Embodiment, and the description is abbreviate | omitted.

  As shown in FIG. 6, the transmission line interlayer connection structure 200 in the second embodiment connects the microstrip line 12 and the strip line 13. The strip line 13 includes a first ground conductor layer 2A, a second dielectric layer 1B, a second conductor layer 3B, a third dielectric layer 1C, and a third ground conductor layer 2C.

<Third Embodiment>
FIG. 7 is an exploded perspective view showing a schematic configuration of a third embodiment of the transmission line interlayer connection structure in the present invention.

  In the second embodiment, the transmission line interlayer connection structure for connecting the microstrip line and the strip line has been described. However, in the third embodiment, the transmission line interlayer connection structure of the present invention is referred to as a microstrip line. It was applied to the connection with the coplanar line. In addition, the same code | symbol is attached | subjected to the same structure as 1st Embodiment, and the description is abbreviate | omitted.

  As shown in FIG. 7, the transmission line interlayer connection structure 300 in the third embodiment connects the microstrip line 12 and the coplanar line 14. The coplanar line 14 includes a second ground conductor layer 2B, a third dielectric layer 1C, and a third conductor layer 3C.

  As shown in the above embodiment, the via hole group in the structure of Patent Document 2 has an IVH (non-through hole) structure, whereas in the structure of the present invention, the via hole group has a through hole structure. The connection structure is easier to manufacture, and the same or better characteristics can be obtained.

  In the second embodiment described above, the combination of the microstrip line and the strip line has been described. In the third embodiment, the combination of the microstrip line and the coplanar line has been described. The present invention is not limited, and any two combinations of a microstrip line, a strip line, and a coplanar line are possible.

  The material specification for realizing the transmission line interlayer connection structure of the present invention is not particularly limited as long as it is a general multilayer wiring board material, and ceramic or organic wiring board materials can be used.

  In order to suppress transmission loss, a wiring board material having a low dielectric constant and a low dielectric loss tangent is preferable. As such a material, for example, MCL-LX-67Y (manufactured by Hitachi Chemical Co., Ltd., trade name) and GEA-LX-67Y (manufactured by Hitachi Chemical Co., Ltd.) Product name).

  In addition, there is no particular restriction on the copper foil used when manufacturing the multilayer wiring board, and a general one can be used. However, in order to suppress transmission loss, the roughened shape of the copper foil is as flat as possible. Is preferred. As such a material, for example, 3EC-VLP-12 (Mitsui Metal Mining Co., Ltd., trade name) is available.

  Examples of the transmission line interlayer connection structure of the present invention will be described below.

  First, the manufacturing procedure of an Example is demonstrated. FIG. 8 is a flowchart showing the manufacturing procedure of the embodiment.

  First, a copper foil-clad laminate with a plate thickness of 0.3 mm and a copper foil thickness of 12 μm (made by Hitachi Chemical Co., Ltd., product name MCL-LX-67Y, a via hole is drilled at a position surrounding a slot to be formed later by etching. Then, the inner layer circuit board (2A, 1C, 2B) is manufactured by patterning the 5 mm square slot 6A and the slot 6B by etching (step S1).

  Next, 12 μm copper foil (trade name 3EC-VLP-12, manufactured by Mitsui Mining & Smelting Co., Ltd.), prepreg (trade name GEA-LX-67Y, manufactured by Hitachi Chemical Co., Ltd.), inner layer obtained in step S1 from the top Circuit board, prepreg (manufactured by Hitachi Chemical Co., Ltd., trade name GEA-LX-67Y), 12 μm copper foil (trade name 3EC-VLP-12, made by Mitsui Mining & Smelting Co., Ltd.) A multilayer circuit board (3A, 1A, 2A, 1C, 2B, 1B, 3B) that is laminated and integrated under conditions of a pressure of 3 MPa and a time of 60 minutes is manufactured (step S2).

  Finally, via holes are formed in the multilayer circuit board obtained in step S2 at positions surrounding the slots 6A and 6B formed in the inner layer circuit board, and then electroless plating is performed. Then, the feed line 4A and 4B having a width of 0.7 mm, the ground conductor patterns 5A and 5B at the tip of the feed line, and the slits 8A and 8B are patterned by etching to obtain the transmission line interlayer connection structure 100 for 24 GHz (step S3). .

<Comparative Example 1>
Here, the transmission line interlayer connection structure of the comparative example will be described. Hereinafter, the manufacturing procedure of the embodiment comparative example will be described. FIG. 9 is a flowchart showing the manufacturing procedure of the comparative example.

  First, a copper foil-clad laminate with a thickness of 0.3 mm and a thickness of 12 μm (made by Hitachi Chemical Co., Ltd., trade name MCL-LX-67Y, 5 mm square slot 6A and slot 6B, 3 mm square The parasitic patch pattern 9A and the parasitic patch pattern 9B are patterned by etching (FIG. 11) to produce the inner layer circuit boards (2A, 1C, 2B) (step S1 ′).

  Next, 12 μm copper foil (trade name 3EC-VLP-12, manufactured by Mitsui Mining & Smelting Co., Ltd.), prepreg (trade name GEA-LX-67Y, manufactured by Hitachi Chemical Co., Ltd.), inner layer obtained in step S1 from the top Circuit board, prepreg (manufactured by Hitachi Chemical Co., Ltd., trade name GEA-LX-67Y), 12 μm copper foil (trade name 3EC-VLP-12, made by Mitsui Mining & Smelting Co., Ltd.) A multilayer circuit board (3A, 1A, 2A, 1C, 2B, 1B, 3B) laminated and integrated under the conditions of a pressure of 3 MPa and a time of 60 minutes is manufactured (step S2 ′).

  Finally, through-holes are drilled in positions surrounding the slot 6A and the slot 6B formed in the inner layer circuit board on the multilayer circuit board obtained in step S2 ', and then electroless plating is performed. Then, the feed line 4A and the feed line 4B having a width of 0.7 mm, the ground conductor pattern 5A and the ground conductor pattern 5B, the space 8A and the space 8B are patterned by etching (FIG. 12), and the transmission line interlayer connection structure 1000 for 24 GHz (FIG. 12). 10) is obtained (step S3 ′).

  A high-frequency probe (manufactured by Cascade, product name ACP-GSG500) is brought into contact with the transmission line 4A and the transmission line 4B with respect to the transmission line interlayer connection structures 100 and 1000 for 24 GHz manufactured as described above, and a coaxial cable (manufactured by SUHNER). In addition to supplying power from a network analyzer (manufactured by Agilent Technologies, product name E8364B) connected via a product name SUCOFLEX100), the power is transmitted from the transmission line 4A to the end face of the transmission line 4B. The transmission loss was measured. The result of measuring the reflection loss is shown in FIG. 13, and the result of measuring the transmission loss is shown in FIG. Table 1 summarizes the characteristics of each transmission line interlayer connection structure at 24 GHz.

  From FIG. 13 and Table 1, it can be seen that the transmission line interlayer connection structure 100 has a smaller reflection loss near 24 GHz than the transmission line interlayer connection structure 1000, and therefore the radiation of electromagnetic waves near this frequency is large. 14 and Table 1, it can be seen that the transmission line interlayer connection structure 100 has a transmission loss in the vicinity of 24 GHz smaller than that of the transmission line interlayer connection structure 1000, and a wide frequency region in which the transmission loss is small.

  Finally, as a capture, Table 4 shows a comparison of transmission loss of the interlayer connection structure of the present embodiment and Patent Document 2 under the analysis conditions and analysis models shown in Tables 2 and 3, respectively. The electromagnetic field simulator used is “HFSS” (trade name) manufactured by Ansoft.

It is a disassembled perspective view which shows schematic structure of 1st Embodiment of the transmission line interlayer connection structure in this invention. It is a top view of a conductor layer. It is a top view of the modification of a conductor layer It is a top view of a ground conductor layer. A three-layer transmission line constructed by laminating and integrating a first conductor layer, a first dielectric layer, a first ground conductor layer, a second dielectric layer, and a second conductor layer in this order. It is a disassembled perspective view which shows schematic structure of an interlayer connection structure. It is a disassembled perspective view which shows schematic structure of 2nd Embodiment of the transmission line interlayer connection structure in this invention. It is a disassembled perspective view which shows schematic structure of 3rd Embodiment of the transmission line interlayer connection structure in this invention. It is a flowchart for demonstrating the manufacture procedure of an Example. It is a flowchart for demonstrating the manufacture procedure of a comparative example. It is a disassembled perspective view which shows schematic structure of the transmission line interlayer connection structure of a comparative example. It is a top view of the ground conductor layer of a comparative example. It is a top view of the conductor layer of a comparative example. It is a graph which shows the frequency characteristic of the reflection loss of an Example and a comparative example. It is a graph which shows the frequency characteristic of the transmission loss of an Example and a comparative example.

Explanation of symbols

100, 200, 300, 400 Transmission line interlayer connection structure 1000 according to the present invention Transmission line interlayer connection structure 1A according to comparative example (prior art) 1st dielectric layer 1B 2nd dielectric layer 1C 3rd dielectric layer 2A 1st ground conductor layer 2B 2nd ground conductor layer 2C 3rd ground conductor layer 3A 1st conductor layer 3B 2nd conductor layer 3C, 3A ', 3B' conductor layer 4A 1st feed line 4B 2nd Feed line 5A First ground conductor pattern 5B Second ground conductor pattern 6A First slot 6B Second slot 7A, 7B Slit 8A, 8B Space 9A, 9B Parasitic patch pattern 10 Conductor layer and ground conductor layer Via hole group 11 connecting the ground conductor layers 12 microstrip line 13 strip line 14 coplanar line 15 first transmission line 16 second transmission line

Claims (3)

A first conductor layer having a first ground conductor pattern connected to the ground conductor layer at the end of the first feeder line, a first dielectric layer, and a first slot are formed. A first transmission line configured by laminating a first ground conductor layer and a second dielectric layer;
A second conductor layer in which a second ground conductor pattern having the same potential as that of the ground conductor layer is connected to the terminal portion of the second feeder line, a third dielectric layer, and a second slot are formed. A second transmission line configured by laminating a second ground conductor layer,
The first conductor layer, the first ground conductor layer, the second ground conductor layer, and the second conductor layer are stacked in a unified manner so that the layers are in order, the first conductor layer, the first ground conductor layer, the second ground conductor layer, and the second conductor layer. Between the first slot and the second slot between the ground conductor pattern, the first ground conductor layer, the second ground conductor layer, and the second ground conductor pattern. Electrically connected by a group of via holes formed in
The length of the first slot in the direction parallel to the first feed line and the length in the direction perpendicular to the first feed line are at least 0.5 times the effective line wavelength of the frequency to be used,
The length of the second slot in the direction parallel to the second feed line and the length in the direction perpendicular to the second feed line are at least 0.5 times the effective line wavelength of the frequency used,
The interval between the via hole groups is not more than one quarter of the line effective wavelength of the frequency used,
A slit is formed in each of a connection portion between the first feed line and the first ground conductor pattern and a connection portion between the second feed line and the second ground conductor pattern. Transmission line interlayer connection structure. Without the second ground conductor layer and the third dielectric layer, the first conductor layer, the first dielectric layer, the first ground conductor layer, and the second dielectric 2. The transmission line interlayer connection structure according to claim 1, wherein the transmission line interlayer connection structure is formed by stacking and integrating a layer and the second conductor layer in this order. The transmission line interlayer connection according to claim 1 or 2 , wherein the first transmission line and the second transmission line are any combination of a microstrip line, a strip line, and a coplanar line. Construction.