JP4503476B2 - High frequency line-waveguide converter - Google Patents

Description

      The present invention relates to a high-frequency line-waveguide converter for converting and propagating high-frequency signals such as microwaves and millimeter waves, and in particular, there is little conversion loss of high-frequency signals, and there is no leakage of high-frequency signals, resulting in miniaturization. The present invention relates to a possible high-frequency line-waveguide converter.

An example of a conventional high-frequency line-waveguide converter is shown in FIG. This conventional example is disclosed in the “waveguide / microstrip line converter” of Patent Document 1, and is composed of a strip conductor pattern 103 and a ground conductor pattern 102 formed on a dielectric substrate 101. A microstrip line and a waveguide 107 formed at right angles to the bottom surface of the dielectric substrate 101 are connected via a ground conductor pattern extraction portion 106 to convert a high-frequency signal with low loss.
JP 2003-273612 A

      However, in the technique disclosed in Patent Document 1 described above, since the microstrip line composed of the strip conductor pattern 103 and the ground conductor pattern 102 formed on the dielectric substrate 101 is employed, the dielectric substrate A high-frequency signal leaked on 101, and it was necessary to cover the upper surface of the converter with a cover or the like. Furthermore, it is necessary to secure the distance from the upper surface of the microstrip line to the cover so as not to affect the electromagnetic field of the microstrip line, and there is a situation that the size cannot be reduced.

      The present invention has been made in view of the above-described conventional circumstances, and provides a high-frequency line-waveguide converter that has low conversion loss of a high-frequency signal and that can be reduced in size without leakage of the high-frequency signal. With the goal.

In order to solve the above-mentioned problem, a high-frequency line-waveguide converter according to the present invention according to claim 1 is a multilayer dielectric substrate in which first, second, third and fourth dielectric substrates are laminated, a first ground conductor said formed so as to cover the surface entire one surface of the first dielectric substrate serving as one surface of the multilayer dielectric substrate, one face of said third dielectric substrate A second ground conductor formed so as to have a predetermined shape of holes, and a predetermined shape so as to overlap a part of the holes of the second ground conductor on one surface of the second dielectric substrate. And the third and fourth ground conductors formed so as to have holes in a shape overlapping with the holes in the second ground conductor on both surfaces of the fourth dielectric substrate, respectively. The multilayer dielectric substrate provided around the holes of the second, third and fourth ground conductors. A plurality of via holes penetrating therethrough to electrically connect the first, second, third and fourth ground conductors, and empty spaces in the second, third and fourth ground conductors; A waveguide connected to the other surface of the fourth dielectric substrate, which is the other surface of the multilayer dielectric substrate, in accordance with the position of the hole, via a base plate, of the base plate A through hole is provided at a position coincident with the opening of the waveguide, and the other surface of the first dielectric substrate faces one surface of the second dielectric substrate in the multilayer dielectric substrate. The other surface of the second dielectric substrate and the one surface of the third dielectric substrate face each other, and the other surface of the third dielectric substrate and the fourth dielectric substrate One surface of the multi-layer dielectric substrate is laminated with the surface facing each other. The first, the second, the third and the fourth dielectric substrates and the positions of the holes of the second, third and fourth ground conductors surrounded by the plurality of via holes, and A dielectric waveguide including a portion of the strip conductor that overlaps the air hole is configured, and the dielectric waveguide matches the impedance between the strip conductor and the waveguide so that the strip conductor And a signal between the waveguide and the waveguide.

      The high-frequency line-waveguide converter having the above-described configuration is provided at the positions of the holes of the second, third, and fourth ground conductors surrounded by the plurality of via holes in the multilayer dielectric substrate. A dielectric waveguide including a portion overlapping the first, second, third and fourth dielectric substrates and the holes of the strip conductor is formed, and a high frequency signal is formed by projecting the strip conductor into the dielectric waveguide. Is propagated into the dielectric waveguide. Further, a high frequency signal is propagated to a waveguide connected to the bottom surface of the multilayer dielectric substrate. The surface of the multilayer dielectric substrate above the strip conductor is covered with the first ground conductor. Thus, the converter between the strip line formed in the multilayer dielectric substrate and the waveguide connected to the lower side of the multilayer dielectric substrate is configured in the multilayer dielectric substrate. There is no leakage of high-frequency signals to the upper side of the body substrate, and since it is not necessary to cover the body substrate with a cover or the like as in the prior art, the height can be reduced.

  A high-frequency line-waveguide converter according to a second aspect of the present invention is the high-frequency line-waveguide converter according to the first aspect, wherein the second, third and fourth grounds are used. The shape of the overlapping holes in the conductor is a rectangle or an ellipse.

      As described above, according to the high-frequency line-waveguide converter of the present invention, between the strip line formed in the multilayer dielectric substrate and the waveguide connected below the multilayer dielectric substrate. Since the converter is configured in the multilayer dielectric substrate, there is no leakage of high-frequency signals above the multilayer dielectric substrate. Further, since it is not necessary to cover with a cover or the like as in the prior art, it is possible to reduce the size in the height direction, and the distance between the strip conductor and the bottom surface of the multilayer dielectric substrate is a quarter of the in-tube wavelength of the waveguide. Therefore, impedance matching between the strip line and the waveguide can be achieved, and the conversion loss of the high-frequency signal can be minimized.

      Hereinafter, an embodiment of the high-frequency line-waveguide converter of the present invention will be described in detail with reference to FIG. FIG. 1 is a configuration diagram of a high-frequency line-waveguide converter according to an embodiment of the present invention. FIG. 1 (a) is a cross-sectional view taken along line AA ', and FIG. 1 (b) is a bottom view seen from below. FIG. The high-frequency line-waveguide converter of this embodiment is applied to, for example, a millimeter-wave module unit such as a millimeter-wave vehicle-mounted radar, and performs signal conversion from a microstrip line or a strip line to a waveguide in a high-frequency circuit. It is.

      In FIG. 1, 1 is a first dielectric substrate, 2 is a second dielectric substrate, 3 is a third dielectric substrate, 4 is a fourth dielectric substrate, 1a is a first ground conductor, 2a is a strip conductor, 3a is 2nd ground conductor, 4a is 3rd ground conductor, 4b is 4th ground conductor, 5 is a multilayer dielectric substrate, 6 is a base plate, 7 is a via hole (cylindrical conductor), 8 is a strip line, 9 is a waveguide And 10 are waveguides, and 11 is a dielectric waveguide.

      The first ground conductor 1a is formed over the entire area of one surface (front surface) of the first dielectric substrate 1 serving as one surface (upper surface) of the multilayer dielectric substrate 5, and the second ground conductor 3a is formed of the third dielectric substrate. The strip conductor 2a is formed on one surface (upper surface) of the second dielectric substrate 2 so as to have a void in the second ground conductor 3a. The third ground conductor 4a and the fourth ground conductor 4b are formed in a predetermined shape (rectangular shape) so as to overlap a part of the hole. The second ground conductor 3a Are formed so as to have vacancies that overlap the vacancies. The plurality of via holes 7 are provided around the holes of the second ground conductor 3a, the third ground conductor 4a, and the fourth ground conductor 4b, and penetrate the multilayer dielectric substrate 5 to form the first ground conductor 1a. The second ground conductor 3a, the third ground conductor 4a, and the fourth ground conductor 4b are electrically connected.

      The multilayer dielectric substrate 5 is formed by laminating the first dielectric substrate 1, the second dielectric substrate 2, the third dielectric substrate 3 and the fourth dielectric substrate 4 on the base plate 6. The other surface (bottom surface) of the body substrate 1 and one surface (top surface) of the second dielectric substrate 2 face each other, and the other surface (bottom surface) of the second dielectric substrate 2 and the third dielectric substrate 3 This is a laminated structure in which one surface (upper surface) faces and the other surface (bottom surface) of the third dielectric substrate 3 faces one surface (upper surface) of the fourth dielectric substrate 4. In the multilayer dielectric substrate 5, the first dielectric substrate 1 is positioned at the holes of the second ground conductor 3 a, the third ground conductor 4 a and the fourth ground conductor 4 b surrounded by the plurality of via holes 7. The second dielectric substrate 2, the third dielectric substrate 3, the fourth dielectric substrate 4, and the dielectric waveguide 11 composed of portions overlapping the holes of the strip conductor 2a are configured.

      Further, the base plate 6 has a fourth dielectric that serves as the other surface (bottom surface) of the multilayer dielectric substrate 5 in accordance with the positions of the holes of the second ground conductor 3a, the third ground conductor 4a, and the fourth ground conductor 4b. A waveguide portion 11 connected to the other surface (bottom surface) of the substrate 4 is provided, and the dielectric waveguide 11 is connected to the waveguide 10 via the waveguide portion 11 of the base plate 6. .

      The strip line 8 includes a first dielectric substrate 1 and a second dielectric substrate 2, a strip conductor 2a, and a first ground conductor 1a and a second ground conductor 3a. The strip conductor 2a is placed in the dielectric waveguide 9. It is a protruding structure.

      In the high-frequency line-waveguide converter of the present embodiment, the surface of the multilayer dielectric substrate 5 above the strip conductor 2a is covered with the first ground conductor 1a. The first dielectric substrate 1, the second dielectric substrate 2, and the third dielectric are located at the positions of the holes of the second ground conductor 3 a, the third ground conductor 4 a, and the fourth ground conductor 4 b surrounded by the via holes 7. A dielectric waveguide 11 composed of a portion overlapping the holes of the body substrate 3 and the fourth dielectric substrate 4 and the strip conductor 2a is formed, and the strip conductor 2a is projected into the dielectric waveguide 11 so that the strip The high-frequency signal of the line 8 is propagated into the dielectric waveguide 11, and the dielectric waveguide 11 is further connected to the bottom surface of the multilayer dielectric substrate 5 via the waveguide portion 9 formed in the base plate 6. A high-frequency signal is propagated to the waveguide 10 connected to.

      As described above, the dielectric waveguide 11 is used as a transducer between the strip line 8 formed in the multilayer dielectric substrate 5 and the waveguide 10 connected below the multilayer dielectric substrate 5. Since it is configured in the body substrate 5, there is no leakage of high frequency signals to the upper side of the multilayer dielectric substrate 5, and it is not necessary to cover with a cover or the like as in the prior art, so that it is possible to reduce the size in the height direction. it can.

      Further, the thickness of the dielectric substrate laminated by the second dielectric substrate 2, the third dielectric substrate 3, and the fourth dielectric substrate 4 is set to ¼ of the in-tube wavelength λg of the waveguide 10. As a result, the distance between the strip conductor 2a and the bottom surface of the multilayer dielectric substrate 5 becomes a quarter of the in-tube wavelength λg of the waveguide 10, so that impedance matching between the strip line 8 and the waveguide 10 is achieved. Therefore, the conversion loss of the high frequency signal can be minimized.

It is a block diagram of the high frequency line-waveguide converter based on one Example of this invention, Fig.1 (a) is sectional drawing in AA 'of FIG.1 (b), FIG.1 (b) is from the downward direction. It is the bottom view seen. It is a perspective view of the conventional high frequency track-waveguide converter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... 1st dielectric substrate, 2 ... 2nd dielectric substrate, 3 ... 3rd dielectric substrate, 4 ... 4th dielectric substrate, 1a ... 1st ground conductor, 2a ... Strip conductor, 3a ... Second ground conductor, 4a ... Third ground conductor, 4b ... Fourth ground conductor, 5 ... Multi-layer dielectric substrate, 6 ... Base plate, 7. ..Via hole, 8 ... strip line, 9 ... waveguide section, 10 ... waveguide, 11 ... dielectric waveguide

Claims (2)

A multilayer dielectric substrate in which first, second, third and fourth dielectric substrates are laminated;
A first ground conductor formed so as to cover the surface entire one surface of the first dielectric substrate serving as the multilayer dielectric a surface of a substrate,
A second ground conductor formed to have a predetermined shape of a hole on one surface of the third dielectric substrate;
A strip conductor formed in a predetermined shape so as to overlap a part of a hole in the second ground conductor on one surface of the second dielectric substrate;
A third ground conductor and a fourth ground conductor formed on both surfaces of the fourth dielectric substrate so as to have holes in a shape overlapping with the holes in the second ground conductor,
The first, second, third, and fourth ground conductors are provided around the holes of the second, third, and fourth ground conductors and penetrate the multilayer dielectric substrate. A plurality of via holes that electrically connect
Connected to the other surface of the fourth dielectric substrate, which is the other surface of the multilayer dielectric substrate, through a base plate in accordance with the positions of the holes of the second, third and fourth ground conductors A waveguide, and
A through hole is provided at a position corresponding to the opening of the waveguide in the base plate,
In the multilayer dielectric substrate, the other surface of the first dielectric substrate faces one surface of the second dielectric substrate, and the other surface of the second dielectric substrate and the third dielectric substrate. The other surface of the dielectric substrate is faced, the other surface of the third dielectric substrate and the one surface of the fourth dielectric substrate are faced and laminated,
In the multilayer dielectric substrate, the first, second, third, and third positions of the second, third, and fourth ground conductors surrounded by the plurality of via holes are positioned. A dielectric waveguide including the fourth dielectric substrate and a portion of the strip conductor that overlaps the hole;
The dielectric waveguide converts the signal between the strip conductor and the waveguide by matching the impedance between the strip conductor and the waveguide. Waveguide converter.   2. The high-frequency line-waveguide converter according to claim 1, wherein a shape of an overlapping hole in the second, third, and fourth ground conductors is a rectangle or an ellipse.

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