JP5183546B2 - Waveguide type rat race circuit - Google Patents

Description

  The present invention relates to a rat race circuit often used in a high-frequency circuit, and more particularly to a waveguide rat race circuit using a waveguide type transmission line.

  A rat race circuit is known as one used as a phase shift circuit or a directional coupling circuit in a high-frequency circuit. The rat race circuit realizes functions as a phase shift circuit and a directional coupling circuit by providing four input / output ports at specific positions of a circular transmission line having a specific length. A configuration using a stripline or a microstripline is known (see, for example, Patent Document 1).

JP 2001-292012 JP

  However, the conventional rat race circuit as proposed in Patent Document 1 forms an annular transmission line using a strip line or a microstrip line, so that transmission loss in the annular transmission line increases as the frequency increases. However, this increases the loss in the rat race circuit.

  The present invention has been devised in view of such problems in the prior art, and its purpose is to be suitably used in a high-frequency region of the millimeter wave band or higher, and can be downsized and mass-produced. An object of the present invention is to provide a waveguide type rat race circuit excellent in the above.

  The waveguide-type rat race circuit of the present invention is a waveguide-type rat race circuit in which four ports are provided at predetermined positions on the tube wall of the annular waveguide portion, respectively. Are disposed on the upper surface of the dielectric layer and constitute an upper main conductor layer constituting the upper tube wall of the annular waveguide portion, and disposed on the lower surface of the dielectric layer and below the annular waveguide portion. The lower main conductor layer constituting the tube wall and the upper main conductor layer and the lower main conductor layer are electrically connected at a repetition interval of less than half of the wavelength of the high frequency signal. And an inner tube wall through conductor group constituting the inner tube wall of the annular waveguide portion and an outer tube wall through conductor group constituting the outer tube wall of the annular waveguide portion. And the upper main conductor layer, the lower main conductor layer, the inner peripheral pipe wall through conductor group, and the outer peripheral pipe wall through conductor group. The dielectric waveguide line that transmits the high-frequency signal is formed in an annular shape by the region that is arranged, and when the bird's-eye view is obtained, it is obtained by connecting the centroids of adjacent through conductors of the through-conductor group for the inner peripheral pipe wall. The minimum value of the length of the line segment between the two intersections of the straight line passing through the center of gravity of the convex polygon and the side of the convex polygon is less than ½ of the wavelength of the high-frequency signal. It is characterized by being.

  In the waveguide type rat race circuit of the present invention, in the above configuration, the annular waveguide portion includes first and third regions arranged adjacent to each other in parallel, and the first and third regions. Comprising a second region connecting the first and third regions at one end of the first region and a fourth region connecting the first and third regions at the other end of the first and third regions. In this case, the inner circumferential tube wall through conductor group is arranged linearly along the boundary between the first and third regions.

  In the present invention, the dielectric layer may be a laminate in which a plurality of dielectrics are laminated in layers, or may be a single layer made of a dielectric in the laminate.

  Further, in the present invention, the figure obtained by connecting the centroids of the adjacent through conductors of the inner peripheral pipe wall through conductor group only needs to be a convex polygon as a whole, and the range in which the effect of the present invention is achieved. There may be a portion that is not locally a convex polygon.

  According to the waveguide-type rat race circuit of the present invention, the annular transmission line constituting the rat-lace circuit includes the annular waveguide portion constituted by the waveguide-type transmission line. Since the transmission loss in the annular waveguide portion is small, a waveguide type rat race circuit having excellent electrical characteristics in the high frequency region can be obtained.

  Further, according to the waveguide-type rat race circuit of the present invention, the annular waveguide portion includes the upper main conductor layer, the lower main conductor layer, and the inner peripheral pipe disposed on the upper and lower surfaces and inside of the dielectric layer. Since it is composed of dielectric waveguide lines with wall through conductor groups and outer tube wall through conductor groups, the annular waveguide section can be reduced in size and easily formed in the dielectric. Therefore, it is possible to obtain a waveguide type rat race circuit that can be miniaturized and is excellent in mass productivity.

  Furthermore, according to the waveguide-type rat race circuit of the present invention, the convex polygon obtained by connecting the centroids of adjacent through conductors of the inner conductor wall through conductor group when viewed from the top, Since the minimum value of the length of the line segment between the two intersections of the straight line passing through the center of gravity and the side of the convex polygon is less than ½ of the wavelength of the high frequency signal, the upper main conductor layer, A resonance phenomenon does not occur even if electromagnetic waves leak into the space surrounded by the lower main conductor layer and the inner pipe wall through conductor group, so that a waveguide-type rat race circuit having good electrical characteristics can be obtained. it can.

  Still further, according to the waveguide-type rat race circuit of the present invention, the annular waveguide section includes the first and third regions arranged adjacent to each other in parallel, and one of the first and third regions. A second region connecting the first and third regions at the end and a fourth region connecting the first and third regions at the other end of the first and third regions, and the inner circumference When the through-wall conductor group for a tube wall is arranged linearly along the boundary between the first and third regions, there is no space for generating the above-described resonance phenomenon. A wave tube type rat race circuit can be obtained.

(A) is an external appearance perspective view which shows typically the waveguide type rat race circuit of the 1st example of embodiment of this invention, (b) is the waveguide type rat race circuit shown to (a). It is a top view which shows typically. (A) is an external appearance perspective view which shows typically the waveguide type rat race circuit of the 2nd example of embodiment of this invention, (b) is the waveguide type rat race circuit shown to (a). It is a top view which shows typically. It is a graph which shows the electrical property of the waveguide type rat race circuit of the 1st example of embodiment of this invention. (A) is an external appearance perspective view which shows typically the waveguide type rat race circuit of a comparative example, (b) is a top view which shows typically the waveguide type rat race circuit shown to (a). . It is a graph which shows the electrical property of the waveguide type rat race circuit of a comparative example.

  Hereinafter, a waveguide type rat race circuit of the present invention will be described in detail with reference to the accompanying drawings.

(First example of embodiment)
FIG. 1A is an external perspective view schematically showing a waveguide-type rat race circuit according to a first example of the embodiment of the present invention, and FIG. 1B is a circuit diagram shown in FIG. It is a top view which shows a wave tube type rat race circuit typically. In order to make the internal structure of the waveguide type rat race circuit easy to understand, the dielectric layers constituting the waveguide type rat race circuit are not shown in FIGS. 1 (a) and 1 (b). Further, FIG. 1B shows a state in which all of the upper main conductor layer 51a is removed.

  As shown in FIGS. 1A and 1B, the waveguide type rat race circuit of the present example has a first port 11, a second port 12, A third port 13 and a fourth port 14 are provided at intervals. The annular waveguide section 30 is connected between the first waveguide section 21 connecting the first port 11 and the second port 12, and between the second port 12 and the third port 13. The second waveguide 22 to be connected, the third waveguide 23 to be connected between the third port 13 and the fourth port 14, and the fourth port 14 to the first port 11 The first waveguide section 21, the second waveguide section 22 and the third waveguide section are separated at the frequency used by the waveguide type rat race circuit of this example. The phase shift amount of the wave portion 23 is set to 3π / 2, and the phase shift amount of the fourth waveguide portion 24 is set to 9π / 2. Therefore, the difference between the sum of the phase shift amounts of the first waveguide portion 21, the second waveguide portion 22, and the third waveguide portion 23 and the phase shift amount of the fourth waveguide portion 24 is zero. ing. In order to realize such a phase shift amount, assuming that the guide wavelength of the high-frequency signal in the annular waveguide section 30 at the frequency used by the rat race circuit is λg, the first waveguide section 21 and the second waveguide section are used. The length of the wave portion 22 and the third waveguide portion 23 is substantially set to 3λg / 4, and the length of the fourth waveguide portion 24 is substantially set to 9λg / 4. Yes.

  Further, in the waveguide type rat race circuit of the present example, the annular waveguide portion 30 is disposed on the upper surface of a dielectric layer (not shown) and becomes the upper tube wall of the annular waveguide portion 30. The upper main conductor layer 51a, the lower main conductor layer 51b which is disposed on the lower surface of the dielectric layer and becomes the lower tube wall of the annular waveguide section 30, and the repetition of less than half of the wavelength λ0 of the high frequency signal A through-conductor for an inner peripheral tube wall, which is disposed so as to electrically connect between the upper main conductor layer 51a and the lower main conductor layer 51b at an interval, and serves as an inner peripheral tube wall of the annular waveguide portion 30 And an outer peripheral tube wall through conductor group 52b which becomes a tube wall on the outer peripheral side of the annular waveguide portion 30, and includes an upper main conductor layer 51a, a lower main conductor layer 51b, and an inner peripheral tube wall through conductor. A region surrounded by the group 52a and the outer circumferential tube wall through conductor group 52b is composed of a dielectric waveguide line that transmits a high-frequency signal. Further, in order to prevent leakage of high-frequency signals from the inner pipe wall through conductor group 52a and the outer pipe wall through conductor group 52b, each through conductor and outer circumference constituting the inner pipe wall through conductor group 52a are provided. Sub conductor layers 51c that connect the respective through conductors constituting the tube wall through conductor group 52b are provided between the upper main conductor layer 51a and the lower main conductor layer 51b.

  Further, in the waveguide type rat race circuit of the present example, the annular waveguide portion 30 has an annular upper and lower tube walls as H planes. The first to fourth ports 11 to 14 are configured by openings formed on the outer peripheral wall of the annular waveguide portion 30, and input or output high-frequency signals to the respective ports. For this purpose, first to fourth input / output transmission lines 71 to 74 are connected. The first to fourth input / output transmission lines 71 to 74 are disposed on the upper surface of a dielectric layer (not shown) and disposed on the lower surface of the dielectric layer and the upper main conductor layer 51a serving as the upper tube wall. The lower main conductor layer 51b, which becomes the lower tube wall, is electrically connected to the upper main conductor layer 51a and the lower main conductor layer 51b at a repetition interval less than ½ of the wavelength λ0 of the high-frequency signal. And two rows of through-hole conductor groups 52 for side walls (tube walls on both sides) of the transmission line, the upper main conductor layer 51a, the lower main conductor layer 51b, and two rows The dielectric waveguide line transmits a high-frequency signal by a region surrounded by the side wall through conductor group 52. In the dielectric waveguide lines constituting the first to fourth input / output transmission lines 71 to 74, the sub-conductors connecting the respective through conductors constituting the two side wall through conductor groups 52, respectively. A layer 51c is provided. The annular waveguide portion 30 and the first to fourth input / output transmission lines 71 to 74 are integrally formed. That is, in the annular waveguide portion 30 and the first to fourth input / output transmission lines 71 to 74, the upper main conductor layer 51a, the lower main conductor layer 51b, and the sub conductor layer 51c are integrally formed. Has been.

  Furthermore, in the waveguide type rat race circuit of this example, the upper tube wall and the lower side are arranged on the inner peripheral side of the position where the first to fourth ports 11 to 14 of the annular waveguide portion 30 are formed. Matching pins 61 made of columnar conductors for connecting the tube walls are arranged, whereby the first to fourth input / output transmission lines 71 to 74 and the annular waveguide section 30 are connected to the first to fourth. Impedance matching at ports 11 to 14 is improved.

  In the waveguide-type rat race circuit of this example having such a configuration, for example, a high-frequency signal input to the first port 11 via the first input / output transmission line 71 is an annular waveguide. The part 30 is separated into two high-frequency signals, a high-frequency signal transmitted toward the first waveguide 21 and a signal transmitted toward the fourth waveguide 24 in opposite directions. The two high-frequency signals are in phase with each other in the second port 12 and the fourth port 14, but are out of phase with each other in the third port 13. Therefore, a high frequency signal is output from the second input / output transmission line 72 and the fourth input / output transmission line 74, but no high frequency signal is output from the third input / output transmission line 73. In this way, the circuit of this example functions as a rat race circuit.

  According to the waveguide type rat race circuit of the present example, the annular waveguide portion 30 and the first to fourth input / output transmission lines 71 to 74 have a dielectric waveguide line with a small transmission loss in a high frequency region. Therefore, it is possible to obtain a waveguide type rat race circuit having excellent electrical characteristics in a high frequency region.

  Further, according to the waveguide type rat race circuit of this example, when the guide wavelength of the high frequency signal in the annular waveguide portion 30 is λg, the first waveguide portion 21, the second waveguide portion 22 and The length of the third waveguide 23 is substantially set to 3λg / 4, and the length of the fourth waveguide 24 is substantially set to 9λg / 4. As a result, the first port 11 is compared with a rat race circuit composed of three λg / 4 lines and one 3λg / 4 line arranged between the four ports known in the art. The distance between the second port 12, the distance between the second port 12 and the third port 13, and the distance between the third port 13 and the fourth port 14 can be increased. Therefore, the annular waveguide section 30 can be formed without difficulty using a dielectric waveguide line, and is composed of a dielectric waveguide line having a width of 1/2 or more of the wavelength λ0 of the high-frequency signal. The first to fourth input / output transmission lines 71 to 74 can be easily connected to the first to fourth ports 11 to 14 formed on the outer periphery of the annular waveguide portion 30.

  Furthermore, according to the waveguide type rat race circuit of the present example, the annular waveguide portion 30 and the first to fourth input / output transmission lines 71 to 74 are configured by dielectric waveguide lines. Therefore, compared to the case of using a hollow rectangular waveguide, it can be miniaturized and can be easily formed in a dielectric, so that it can be miniaturized and has excellent mass productivity. A wave tube type rat race circuit can be obtained.

  Furthermore, according to the waveguide type rat race circuit of the present example, when a region surrounded by the upper main conductor layer 51a, the lower main conductor layer 51b, and the inner pipe wall through conductor group 52a is viewed in plan view. In the convex polygon 41 obtained by connecting the centroids of the adjacent through conductors of the inner peripheral pipe wall through conductor group 52a, the straight line passing through the centroid 42 of the convex polygon 41 and the sides of the convex polygon 41 are two. Since the minimum value of the length of the line segment between the intersections is less than ½ of the wavelength λ0 of the high frequency signal, the upper main conductor layer 51a, the lower main conductor layer 51b, and the inner peripheral tube wall through conductor group 52a Resonance due to electromagnetic waves leaking into the space surrounded by can be prevented, so that deterioration of the electrical characteristics of the waveguide rat race circuit can be prevented. This phenomenon will be described in detail below.

  In the dielectric waveguide line composed of the upper main conductor layer 51a, the lower main conductor layer 51b, and the two rows of through-hole conductor groups 52 for the sidewalls disposed on the upper and lower surfaces and inside of the dielectric layer, It has been considered that leakage of high-frequency signals from the through-conductor group for side walls can be prevented by setting the arrangement pitch of the through conductors constituting the conductor group 52 to be less than ½ of the wavelength λ0 of the high-frequency signal. However, the upper main conductor layer 51a, the lower main conductor layer 51b, the inner peripheral pipe wall through conductor group 52a, and the outer peripheral pipe wall through conductor group 52b arranged on the upper and lower surfaces and inside of the dielectric layer are formed. In the waveguide type rat race circuit including the waveguide section 30, when the arrangement pitch of the through conductors constituting the inner pipe wall through conductor group 52a is set to be less than ½ of the wavelength λ0 of the high frequency signal In addition, resonance due to electromagnetic waves leaking into the space surrounded by the upper main conductor layer 51a, the lower main conductor layer 51b, and the inner pipe wall through conductor group 52a occurs, and the electrical characteristics of the waveguide-type rat race circuit. It has been clarified by the inventor's examination that the phenomenon of worsening occurs (see the comparative example in FIG. 4 and the electrical characteristics in FIG. 5). Even when the arrangement pitch of the through conductors constituting the inner pipe wall through conductor group 52a is set to be less than ½ of the wavelength λ0 of the high frequency signal, the inner pipe wall through conductor group 52a is larger than the inner pipe wall through conductor group 52a. This is considered to be caused by a slight distribution of electromagnetic waves of high-frequency signals in a region near the inside.

  In order to prevent the electrical characteristics of the waveguide-type rat race circuit from deteriorating due to this phenomenon, as a result of extensive studies by the present inventors, the upper main conductor layer 51a, the lower main conductor layer 51b, and the inner peripheral tube wall through conductor group When the area surrounded by 52a is viewed in plan, the convex polygon 41 obtained by connecting the centers of adjacent through conductors of the inner peripheral pipe wall through conductor group 52a passes through the center of gravity 42 of the convex polygon 41. By setting the minimum value of the length of the line segment between the two intersections of the straight line and the side of the convex polygon 41 to less than ½ of the wavelength λ 0 of the high frequency signal, the upper main conductor layer 51a and the lower main conductor The frequency at which the electromagnetic wave can resonate in the space surrounded by the layer 51b and the inner pipe wall through conductor group 52a can be shifted to the high frequency side, thereby leaking the high frequency signal lower than the resonable frequency. It was found that resonance due to can be prevented.

  The reason why this effect can be obtained is that when the area surrounded by the inner pipe wall through conductor group 52a is viewed in plan, the centers of adjacent through conductors of the inner pipe wall through conductor group 52a are connected to each other. If the figure is a convex polygon, the minimum length of the line segment between the two intersections of the straight line passing through the center of gravity and the side of the convex polygon is less than half of the wavelength λ0 of the high-frequency signal. If it is satisfied, since any dimension of the convex polygon is smaller than half the wavelength λ0 of the high-frequency signal, the dimension in the direction orthogonal to the longitudinal direction of the figure cannot exist. . This can be understood from the fact that in a rectangular waveguide, when the width of the waveguide is less than half of the wavelength λ0 of the high frequency signal, the high frequency signal cannot propagate.

(Second example of embodiment)
FIG. 2A is an external perspective view schematically showing a waveguide-type rat race circuit according to a second example of the embodiment of the present invention, and FIG. 2B is a circuit diagram shown in FIG. It is a top view which shows a wave tube type rat race circuit typically. In order to facilitate understanding of the internal structure of the waveguide type rat race circuit, the dielectric layers constituting the waveguide type rat race circuit are not shown in FIGS. 2 (a) and 2 (b). Further, FIG. 2B shows a state in which the upper main conductor layer 51a is completely removed. Further, in this example, only differences from the above-described first example will be described, and the same components will be described using the same reference numerals, and redundant description will be omitted.

In the waveguide type rat race circuit of this example, as shown in FIGS. 2A and 2B, the annular waveguide portions 30 are linearly arranged adjacent to each other in a straight line. A region 81 and a third region 83; a semicircular second region 82 connecting the first region 81 and the third region 83 at one end of the first region 81 and the third region 83; The other end portion of the third region 83 comprises a first region 81 and a semicircular fourth region 84 connecting the third region 83. When viewed from the top, the inner circumferential tube wall through conductor group 52a In the waveguide type rat race circuit of this example, which is arranged in a straight line along the boundary between the first region 81 and the third region 83, resonance may occur as was problematic in the first embodiment. Since there is no space in the first place, good characteristics can be obtained.

  The waveguide-type rat race circuit of the present example is similar to the waveguide-type rat race circuit of the first example described above when the through-conductors adjacent to the through-hole conductor group 52a for the inner peripheral tube wall are viewed from above. Corresponds to the case where the length of a line segment between two intersections of a straight line passing through the center of gravity 42 of the convex polygon 41 and the side of the convex polygon 41 is zero in the convex polygon 41 obtained by connecting the centers. To do.

  In the waveguide type rat race circuit of the present invention, the dielectric constant of the dielectric layer is, for example, about 2 to 20. The material of the dielectric layer is not particularly limited as long as it has a characteristic that does not hinder the transmission of high-frequency signals, and a resin such as glass epoxy can be used. It is desirable to use dielectric ceramics from the viewpoints of accuracy in forming and ease of manufacturing. The upper main conductor layer 51a, the lower main conductor layer 51b, and the sub conductor layer 51c are made of a highly conductive metal and have a thickness of about 3 μm to 50 μm, for example. The inner peripheral tube wall through conductor group 52a, the outer peripheral tube wall through conductor group 52b, and the side wall through conductor group 52 function as tube walls on both sides of the dielectric waveguide. Each repetition interval needs to be less than ½ of the wavelength λ0 of the high frequency signal and preferably less than ¼ from the viewpoint of preventing leakage of the high frequency signal. As the inner pipe wall through conductor group 52a, the outer pipe wall through conductor group 52b, the side wall through conductor group 52, and the alignment pin 61, a via hole or a through hole can be used. It is set to about mm to 0.5 mm.

  The waveguide type rat race circuit of the present invention can be manufactured as follows, for example. First, using a slurry obtained by adding and mixing a suitable organic solvent and solvent to a ceramic raw material powder mainly composed of glass, alumina, aluminum nitride, etc., a ceramic green sheet is formed by a doctor blade method or a calender roll method. Make it. Next, an inner peripheral tube wall through conductor group 52a, an outer peripheral tube wall through conductor group 52b, a side wall through conductor group 52, and an alignment pin 61 are formed on the obtained ceramic green sheet using a laser, a punching machine, or the like. A through-hole is formed, and a paste prepared by adding and mixing an appropriate oxide, organic solvent, or the like such as alumina, silica, or magnesia to the metal powder is filled into the through-hole by a thick film printing method and ceramic. Apply to the surface of the green sheet to make a ceramic green sheet with conductor paste. Next, the obtained ceramic green sheets with a conductive paste are laminated and pressed using a hot press apparatus to form a laminate. And when the dielectric layer is made of glass ceramics, the obtained laminate is about 850 ° C. to 1000 ° C., alumina ceramics is about 1500 ° C. to 1700 ° C., and aluminum nitride ceramics is about 1600 ° C. to 1900 ° C. It is produced by firing at a peak temperature of about. The metal powder is preferably copper, gold or silver when the dielectric layer is glass ceramic, and tungsten or molybdenum when the dielectric layer is alumina ceramic or aluminum nitride ceramic.

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and improvements can be made without departing from the spirit of the present invention.

  For example, in the example of the embodiment described above, the example in which the first to fourth ports 11 to 14 are formed on the tube wall on the outer peripheral side of the annular waveguide unit 30 is shown. A port may be formed on the upper tube wall of 30, or a port may be formed on the lower tube wall. When a port is formed in the upper tube wall or the lower tube wall of the annular waveguide portion 30, the through-hole formed in the tube wall of the annular waveguide portion 30 and the through-hole The port may be configured by a signal transmission conductor insulated from the tube wall passing through, or the port may be configured by a slot formed in the tube wall of the annular waveguide portion 30. I do not care.

  In the example of the embodiment described above, an example in which the sub conductor layer 51c is provided is shown, but a configuration in which the sub conductor layer 51c is not provided may be employed.

  Next, a specific example of the waveguide type rat race circuit of the present invention will be described.

  The electrical characteristics in the waveguide type rat race circuit of the first example of the embodiment shown in FIG. 1 were calculated by simulation based on electromagnetic field analysis. As calculation conditions, the dielectric constant and thickness of the dielectric layer were set to 9.4 and 0.45 mm, respectively. The upper main conductor layer 51a, the lower main conductor layer 51b, and the sub conductor layer 51c were each 0.01 mm in thickness, and the sub conductor layer 51c was positioned at the center of the dielectric layer. The annular waveguide portion 30 has a track shape in which a straight portion and a semicircle are combined, and the tube width is 1.08 mm. The inner peripheral tube wall through conductor group 52a, the outer peripheral tube wall through conductor group 52b, and the side wall through conductor group 52 are configured such that cylindrical conductors having a diameter of 0.1 mm are arranged at a pitch of about 0.3 mm. The distance between the pair of through-hole conductor groups 52 and 52 for the first to fourth input / output transmission lines 71 to 74 was 1.15 mm. The minimum length of the convex polygon 41 connecting the adjacent centers of the through-hole conductor group 52a for the inner peripheral tube wall when viewed in plan with a straight line passing through the center of gravity 42 is 0.553 mm, and the length orthogonal thereto is It was 1.73 mm. In this case, if the maximum signal frequency to be used is 76 GHz, the wavelength λ0 of the high-frequency signal is 1.287 mm, and the minimum length obtained by cutting the convex polygon 41 by a straight line passing through the center of gravity 42 is less than λ0 / 2. It is a small value. Further, the position of the matching pin 61 for matching the input / output transmission lines 71 to 74 and the annular waveguide portion 30 was formed at a position separated from the center of each port by 0.75 mm.

Then, the reflection characteristic at the first port 11 (S11), the transmission characteristic between the first and second ports 11 and 12 (S21), and the transmission characteristic between the first and third ports 11 and 13 (S31). The transmission characteristics (S41) between the first and fourth ports 11 and 14 were calculated. FIG. 3 is a graph showing the results. The horizontal axis represents the frequency, and the vertical axis represents the attenuation. The characteristics as a good rat race circuit are shown in the range of 74 GHz to 76 GHz.
(Comparative example)
Next, a waveguide type rat race circuit of a comparative example will be described. 4A is an external perspective view schematically showing a waveguide type rat race circuit of a comparative example, and FIG. 4B is a schematic view of the waveguide type rat race circuit shown in FIG. FIG. In order to make the internal structure of the waveguide type rat race circuit easy to understand, the dielectric layers constituting the waveguide type rat race circuit are not shown in FIGS. 4 (a) and 4 (b). Further, FIG. 4B shows a state in which the upper main conductor layer 51a is completely removed. In addition, the same reference numerals are used for the same constituent elements as those in the above-described embodiment, and redundant description is omitted.

  The electrical characteristics of the waveguide type rat race circuit of the comparative example shown in FIG. 4 were calculated by simulation based on electromagnetic field analysis. As calculation conditions, the dielectric constant and thickness of the dielectric layer were set to 9.4 and 0.45 mm, respectively. The upper main conductor layer 51a, the lower main conductor layer 51b, and the sub conductor layer 51c were each 0.01 mm in thickness, and the sub conductor layer 51c was positioned at the center of the dielectric layer. The annular waveguide portion 30 was an annulus having an inner peripheral radius of 0.5 mm and an outer peripheral radius of 1.68 mm. The inner peripheral tube wall through conductor group 52a, the outer peripheral tube wall through conductor group 52b, and the side wall through conductor group 52 are configured such that cylindrical conductors having a diameter of 0.1 mm are arranged at a pitch of about 0.3 mm. The distance between the pair of through-hole conductor groups 52 and 52 for the first to fourth input / output transmission lines 71 to 74 was 1.15 mm. The region inside the through-hole conductor group 52a for inner peripheral tube wall when viewed from above was a circular shape having a radius of 0.5 mm.

  Then, the reflection characteristic at the first port 11 (S11), the transmission characteristic between the first and second ports 11 and 12 (S21), and the transmission characteristic between the first and third ports 11 and 13 (S31). The transmission characteristics (S41) between the first and fourth ports 11 and 14 were calculated. FIG. 5 is a graph showing the results.

  According to the graph of FIG. 5 showing the electrical characteristics of the waveguide type rat race circuit of the comparative example, in the vicinity of 77.3 GHz, the upper main conductor layer 51a, the lower main conductor layer 51b, and the inner peripheral tube wall through conductor group 52a. A peak due to resonance of the electromagnetic wave leaked in the space surrounded by. In contrast, as described above, in the graph of FIG. 3 showing the electrical characteristics of the waveguide type rat race circuit of the first example of the embodiment of the present invention, no peak due to unnecessary resonance is observed. Good electrical characteristics have been obtained. This confirmed the effectiveness of the present invention.

30: Annular waveguide section
41: Convex polygon
42: Center of gravity
51a: Upper main conductor layer
51b: Lower main conductor layer
52a: Through conductor group for inner peripheral pipe wall
52b: Outer pipe wall through conductor group
81: First area
82: Second area
83: Third area
84: Fourth area

Claims (2)

A waveguide-type rat race circuit in which four ports are provided at predetermined positions on the tube wall of the annular waveguide section,
The annular waveguide portion is disposed on the upper surface of the dielectric layer and constitutes an upper main conductor layer that constitutes an upper tube wall of the annular waveguide portion, and is disposed on the lower surface of the dielectric layer and is disposed on the annular conductor. An electrical connection between the lower main conductor layer constituting the lower tube wall of the wave tube portion and the upper main conductor layer and the lower main conductor layer at a repetition interval of less than ½ of the wavelength of the high-frequency signal For the outer peripheral tube wall constituting the inner peripheral tube wall through conductor group constituting the inner peripheral tube wall of the annular waveguide portion and the outer peripheral tube wall of the annular waveguide portion, arranged to be connected A through conductor group, and transmits the high-frequency signal by a region surrounded by the upper main conductor layer, the lower main conductor layer, the inner pipe wall through conductor group and the outer pipe wall through conductor group. It is configured in an annular shape with a dielectric waveguide line that
In a convex polygon obtained by connecting the centroids of adjacent through conductors of the inner peripheral pipe wall through conductor group when viewed from above, a straight line passing through the centroid of the convex polygon and a side of the convex polygon A waveguide-type rat race circuit, wherein a minimum value of a length of a line segment between two intersections is less than ½ of a wavelength of the high-frequency signal. The annular waveguide portion includes first and third regions arranged adjacent to each other in parallel and a second region connecting the first and third regions at one end of the first and third regions. And a fourth region connecting the first and third regions at the other end of the first and third regions,
2. The waveguide type according to claim 1, wherein when viewed from the top, the through-hole conductor group for the inner peripheral tube wall is linearly arranged along a boundary between the first and third regions. Rat race circuit.

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