JP5219856B2 - 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 according to 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. An upper main conductor layer that is disposed on the upper surface of the dielectric layer and forms an upper tube wall of the annular waveguide portion; and a lower surface of the annular waveguide portion that is disposed on the lower surface of the dielectric layer. An electrical connection is established between the lower main conductor layer constituting the tube wall and the upper main conductor layer and the lower main conductor layer at a repetition interval of less than half the wavelength of the high-frequency signal propagating through the annular waveguide portion. The inner peripheral tube wall through conductor group constituting the inner peripheral tube wall of the annular waveguide portion and the outer peripheral tube constituting the outer peripheral tube wall of the annular waveguide portion, which are arranged so as to be connected to each other A wall through conductor group, the upper main conductor layer, the lower main conductor layer, the inner pipe wall through conductor group and the front Is configured annularly dielectric waveguide line for transmitting a high frequency signal by the first region is a region surrounded by the outer peripheral tube wall through conductor group, out of the first area in which the high-frequency signal is transmitted wherein while positioned in a region surrounded by the first region, the upper main conductor layer, a second region wherein a region closed surrounded by the lower main conductor layer and said inner circumferential tube wall through conductors The dielectric layer is provided with at least one through hole.

  The waveguide-type rat race circuit of the present invention is characterized in that the through hole is filled with a conductor.

  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.

  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, at least one penetration is made in the dielectric layer in the region surrounded by the upper main conductor layer, the lower main conductor layer, and the inner pipe wall through conductor group. Since a hole is provided, when a resonance phenomenon due to leaked electromagnetic waves occurs in the space surrounded by the upper main conductor layer, the lower main conductor layer, and the inner pipe wall through conductor group, the resonance frequency Can be shifted to the high frequency side. Therefore, when the resonance frequency is located within the frequency band to be used, the resonance frequency can be shifted outside the frequency band to be used, thereby preventing deterioration of the electrical characteristics of the waveguide type rat race circuit. can do.

  Furthermore, according to the waveguide-type rat race circuit of the present invention, since the through hole is filled with the conductor, it is surrounded by the upper main conductor layer, the lower main conductor layer, and the inner conductor wall through conductor group. Since the resonance of the electromagnetic wave leaking into the space can be prevented, deterioration of the electrical characteristics of the waveguide type rat race circuit can be prevented.

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

  FIG. 1 (a) is a perspective view schematically showing an example of an embodiment of a waveguide type rat race circuit of the present invention, and FIG. 1 (b) is a waveguide type rat shown in FIG. 1 (a). It is a top view which shows a 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. 1A shows a state where the upper main conductor layer 51a is partially removed, and FIG. 1B shows a state where the upper main conductor layer 51a is completely 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, if the guide wavelength of the high-frequency signal in the annular waveguide section 30 at the frequency used by the rat race circuit is λ, the first waveguide section 21 and the second waveguide section will be described. The length of the wave portion 22 and the third waveguide portion 23 is substantially set to 3λ / 4, and the length of the fourth waveguide portion 24 is substantially set to 9λ / 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. An upper main conductor layer 51a, a lower main conductor layer 51b that is disposed on the lower surface of the dielectric layer and serves as a lower tube wall of the annular waveguide portion 30, and a high-frequency signal propagating through the annular waveguide portion 30 A tube wall on the inner peripheral side of the annular waveguide portion 30 disposed so as to electrically connect the upper main conductor layer 51a and the lower main conductor layer 51b at a repetition interval of less than ½ of the wavelength; An inner peripheral tube wall through conductor group 52a and an outer peripheral tube wall through conductor group 52b which becomes an outer peripheral wall of the annular waveguide portion 30, and an upper main conductor layer 51a and a lower main conductor layer 51b. , A dielectric waveguide line for transmitting a high-frequency signal by a region surrounded by the inner pipe wall through conductor group 52a and the outer pipe wall through conductor group 52b. . 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. Between the upper main conductor layer 51a and the lower main conductor layer 51b at a repetition interval of less than half the wavelength of the high-frequency signal propagating through the transmission line. And two rows of through conductor groups for side walls 52 that serve as side walls (tube walls on both sides) of the transmission line, which are arranged so as to be electrically connected, and have an upper main conductor layer 51a and a lower main conductor layer 51b. , And a region surrounded by two rows of through-hole conductor groups 52 for side walls, and a dielectric waveguide line for transmitting a high-frequency signal. 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 81 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 portion 30 are connected to each other. 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 part 21 and a signal transmitted toward the fourth waveguide part 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. Thus, the waveguide type rat race 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 section 30 is λ, the first waveguide section 21, the second waveguide section 22 and The length of the third waveguide 23 is substantially set to 3λ / 4, and the length of the fourth waveguide 24 is substantially set to 9λ / 4. As a result, the first port 11 is compared with a rat race circuit composed of three λ / 4 lines and one 3λ / 4 line arranged between the four known ports. 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 portion 30 can be formed without difficulty using a dielectric waveguide line, and the first to fourth elements configured with dielectric waveguide lines having a width of about λ / 2. The 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 this example, the dielectric layer in the region surrounded by the upper main conductor layer 51a, the lower main conductor layer 51b, and the inner peripheral pipe wall through conductor group 52a is formed. Since a plurality of resonance suppressing through conductors 45 are provided, 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. Therefore, it is possible to prevent deterioration of electrical characteristics of the waveguide type rat race circuit. This phenomenon will be described in detail below.

  In a dielectric waveguide line composed of an upper main conductor layer, a lower main conductor layer, and two rows of side wall through conductor groups arranged on the upper and lower surfaces and inside of the dielectric layer, the side wall through conductor groups are It is thought that leakage of high frequency signals from the through conductor group for the side wall can be prevented by setting the arrangement pitch of the through conductors to be set to less than ½ of the wavelength of the high frequency signal propagating through the dielectric waveguide line. It was. 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, the arrangement pitch of the through conductors constituting the inner circumferential pipe wall through conductor group 52a is set to 1 of the wavelength of the high-frequency signal propagating through the annular waveguide section 30. Even when it is set to less than / 2, resonance occurs 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 peripheral pipe wall through conductor group 52a, and the waveguide It has been clarified by the present inventors that a phenomenon occurs in which the electrical characteristics of the type rat race circuit deteriorate. This is because even when the arrangement pitch of the through conductors constituting the inner circumference pipe wall through conductor group 52a is set to be less than ½ of the wavelength of the high-frequency signal propagating through the annular waveguide portion 30, the inner circumference tube It may be caused by a slight distribution of electromagnetic waves of high-frequency signals in a region near the inside of the wall through conductor group 52a.

  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 By providing a through-hole in the dielectric layer in the region surrounded by 52a, resonance caused by electromagnetic waves leaking into the space surrounded by the upper main conductor layer, the lower main conductor layer, and the inner conductor wall through-conductor group is provided. It was found that the resonance frequency can be shifted to the high frequency side. This can reduce the substantial dielectric constant in the region surrounded by the upper main conductor layer 51a, the lower main conductor layer 51b, and the inner pipe wall through conductor group 52a by forming a through hole. It is thought to be possible. As a result, when the resonance frequency is located within the frequency band to be used, the resonance frequency can be shifted out of the frequency band to be used, thereby preventing deterioration of the electrical characteristics of the waveguide type rat race circuit. be able to. The shape and number of through holes to be formed can be appropriately set according to the frequency band to be used, the resonance frequency before forming the through holes, the dielectric constant of the dielectric layer, and the like.

  Further, as a result of further studies by the inventor, conductors are formed in through holes formed in a dielectric layer in a region surrounded by the upper main conductor layer 51a, the lower main conductor layer 51b, and the inner peripheral pipe wall through conductor group 52a. To prevent resonance due to electromagnetic waves leaking into the space surrounded by the upper main conductor layer, the lower main conductor layer, and the inner conductor wall through conductor group. I found out that The shape, position and number of the resonance suppressing through conductor 45 are the shape and size of the region surrounded by the upper main conductor layer 51a, the lower main conductor layer 51b, and the inner peripheral pipe wall through conductor group 52a. In addition, the resonance peak due to electromagnetic waves leaking into the space surrounded by the upper main conductor layer, the lower main conductor layer, and the inner peripheral pipe wall through conductor group can be set as appropriate depending on how much the resonance peak is desired to be reduced.

  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 11c 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 of the high-frequency signal transmitted through the dielectric waveguide line from the viewpoint of preventing leakage of the high-frequency signal, and may be less than ¼. preferable. Via holes and through holes can be used as the inner peripheral pipe wall through conductor group 52a, the outer peripheral pipe wall through conductor group 52b, the side wall through conductor group 52, and the resonance suppressing through conductor 45. For example, about 0.05 mm to 0.5 mm. The diameter of the through hole formed in the inner dielectric layer of the inner peripheral tube wall through conductor group 52a when viewed in plan is also set to, for example, about 0.05 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, the inner peripheral tube wall through conductor group 52a, the outer peripheral tube wall through conductor group 52b, the side wall through conductor group 52 and the resonance suppressing through conductor 45 are formed on the obtained ceramic green sheet using a punching machine or the like. A through-hole is formed, and a paste made by adding and mixing a suitable oxide, organic solvent, etc., such as alumina, silica, and magnesia to the metal powder is filled into the through-hole by the thick film printing method. A ceramic green sheet with a conductive paste is prepared by applying to the surface of the ceramic green sheet. 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 constituted by a signal transmission conductor insulated from the passing tube wall, or the port may be constituted by a slot formed in the tube wall of the waveguide.

  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.

  Furthermore, in the example of the embodiment described above, for resonance suppression comprising via holes filled with conductors in the entire through holes formed in the dielectric layer inside the inner pipe wall through conductor group 52a in plan view. Although the example of the through conductor 45 is shown, the resonance suppressing through conductor 45 may be formed of a through hole in which the conductor is attached to the through hole so that the conductor adheres only to the wall surface of the through hole formed in the dielectric layer.

  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 example of the embodiment shown in FIG. 1 were calculated by simulation by 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 annular with an inner radius of 0.55 mm and an outer 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. When viewed from above, the inner region of the inner peripheral tube wall through conductor group 52a has a circular shape with a radius of 0.55 mm, and a total of five resonance suppressing through conductors, one at the center and four on the circumference with a radius of 0.27 mm. 45 was placed. The resonance suppressing through conductors 45 are all cylindrical with a diameter of 0.1 mm.

  Then, the reflection characteristic at port 1 (S11), the transmission characteristic between ports 1 and 2 (S21), the transmission characteristic between ports 1 and 3 (S31), and the transmission characteristic between ports 1 and 4 (S41) were calculated. . FIG. 2 is a graph showing the results, and FIG. 3 is a graph showing the simulation results of the electrical characteristics of the waveguide type rat race circuit of the comparative example in which the resonance suppressing through conductor 45 is removed from the structure shown in FIG. is there. In each graph, the horizontal axis represents frequency and the vertical axis represents attenuation.

  According to the graph of FIG. 3 showing the electrical characteristics of the waveguide type rat race circuit of the comparative example, the upper main conductor layer 51a, the lower main conductor layer 51b, and the inner peripheral pipe wall through conductor group 52a are near 76.5 GHz. In the graph of FIG. 2 showing the electrical characteristics of the waveguide type rat race circuit of the present invention, a peak due to unnecessary resonance is not seen at all. It can be seen that good electrical characteristics are obtained. This confirmed the effectiveness of the present invention.

30: Annular waveguide section
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

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. A lower main conductor layer constituting a lower tube wall of the wave tube portion, and the upper main conductor layer and the lower side at a repetition interval of less than half of the wavelength of the high-frequency signal propagating through the annular waveguide portion A through conductor group for an inner peripheral tube wall constituting an inner peripheral tube wall of the annular waveguide portion and an outer periphery of the annular waveguide portion, which are arranged so as to electrically connect the main conductor layers. A peripheral conductor wall through conductor group constituting a pipe wall, and surrounded by 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 the first region is a region which is configured annularly dielectric waveguide line for transmitting a high frequency signal, the high frequency signal A region surrounded by the first region with located outside of the first region to be transmitted, the upper main conductor layer, said enclosed by the lower main conductor layer and said inner circumferential tube wall through conductors A waveguide-type rat race circuit, wherein at least one through hole is provided in the dielectric layer in the second region which is a closed region.   The waveguide-type rat race circuit according to claim 1, wherein the through hole is filled with a conductor.

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