JP6239477B2 - Planar transmission line / waveguide converter - Google Patents

Description

  The present invention relates to a planar transmission line / waveguide converter.

  In the field of wireless communication having a high frequency such as millimeter waves, a waveguide is often used as a transmission line because it has an advantage of low transmission loss. On the other hand, the main circuit portion is composed of a planar transmission line such as a microstrip line or a coplanar line. For this reason, a planar transmission line / waveguide converter capable of mutually converting the power transmitted through the planar transmission line and the power transmitted through the waveguide is required.

  As such a planar transmission line / waveguide converter, for example, there are technologies disclosed in Patent Document 1 and Non-Patent Document 1. In Non-Patent Document 1, since a patch antenna is used as a matching element and electromagnetically coupled with a coplanar line for conversion, a part called back short shown in Patent Document 1 can be reduced and the size can be reduced. is there. However, since a patch antenna is used, there is a problem that even if the substrate has a relative dielectric constant of 2.2, the specific band is about 3% (reflection characteristics <−20 dB).

From the equation shown in Non-Patent Document 1, the following relationship is derived.

  Here, BW indicates the bandwidth, Q indicates the Q (Quality) value, t indicates the thickness of the substrate, and εr indicates the relative dielectric constant of the substrate. From equation (1), it can be seen that the bandwidth is proportional to the substrate thickness and inversely proportional to the dielectric constant. That is, when the substrate is thin and the relative dielectric constant is high, the bandwidth decreases.

  In order to reduce the size, millimeter waves often use a thin substrate having a high relative dielectric constant of about 7 to 10 such as alumina. If the same method as that of Patent Document 1 is adopted and analyzed using electromagnetic field analysis, even if the substrate thickness is the same, the specific band is reduced by about 1/10 from about 3.2% to about 0.32%. For this reason, it is difficult to employ a method such as that of Patent Document 1 with a high dielectric material such as an alumina substrate.

  In order to solve such problems, a technique aimed at widening the bandwidth has been disclosed.

  In the technique disclosed in Patent Document 2, the number of patch antennas which are matching elements is increased, and each patch antenna is resonated at a frequency shifted up and down from the resonance frequency to achieve a wide band. According to such a configuration, the specific band can be increased from 3.2% to 7.2%, and an improvement of about 2.25 times can be achieved.

  In the technique disclosed in Patent Document 3, a double resonator is generated by providing a cavity resonator between a waveguide and a matching element to achieve a wide band. According to such a technique, the specific bandwidth can be increased from 3.2% to 7.2%, and an improvement of about 2.25 times can be achieved.

  In the technique disclosed in Patent Document 4, weakening of electromagnetic coupling between the coplanar line and the patch antenna caused by the high dielectric constant of the alumina substrate is improved by coupling the coplanar line and the patch antenna with a through hole. doing. In such a technique, the transmission characteristic is -2.2 dB and the reflection characteristic is -19.2 dB at 60 GHz.

JP 2000-244212 A JP 2013-138356 A JP 2012-049862 A JP 2008-131513 A

Iizuka, Hideo, Toshiaki Watanabe, and Kunitoshi NISHIKAWA. "Millimeter-wave microstrip line to waveguide transition fabricated on a single layer dielectric substrate." IEICE transactions on communications 85.6 (2002): 1169-1177.

  By the way, in the techniques disclosed in Patent Document 2 and Patent Document 3, the specific band can be improved by about 2.25 times. However, when the substrate is changed to an alumina substrate in Patent Document 1, the specific band is 0. As a result, only a specific bandwidth of about 0.72% (= 3.2% × 2.25 × 0.1 times) can be expected, so that it is difficult to employ an alumina substrate. There is.

  In the technique disclosed in Patent Document 4, the pass characteristic is -2.2 dB, and in a converter that generally requires a pass characteristic (conversion loss) of about -0.5 to 1.0 dB, the loss is low. There is a problem that it is excessive.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a planar transmission line / waveguide converter having a wide band and low loss.

In order to solve the above problems, the present invention provides a planar transmission line / waveguide converter capable of mutually converting power transmitted by a planar transmission line and power transmitted by a waveguide. A short-circuit plate disposed substantially parallel to an opening surface of one opening of the wave tube; a planar transmission line having an end disposed in the opening; and the waveguide a predetermined distance from the short-circuit plate A matching element that is spaced apart in the axial direction and is substantially parallel to the short-circuit plate and electromagnetically coupled to the planar transmission line, and is disposed between the short-circuit plate and the matching element. The first dielectric plate is disposed on the opposite side of the first dielectric plate across the matching element, and is spaced apart from the matching element in the axial direction of the waveguide by a predetermined distance. a second dielectric plate arranged, the first and second dielectric It is interposed between, and having a at least one of the metal plates and the dielectric plate having an opening corresponding to the opening of the waveguide.
According to such a configuration, it is possible to obtain a planar transmission line / waveguide converter having a wide band and low loss.

Further, the present invention is characterized in that a cut is formed in a part of the short-circuit plate, and an end of the planar transmission line is arranged in the cut.
According to such a configuration, the planar transmission line / waveguide converter in which the planar transmission line is disposed in the cut can be reduced in bandwidth and loss.

The present invention is characterized in that an end of the planar transmission line is connected to the matching element.
According to such a configuration, the planar transmission line / waveguide converter in which the end of the planar transmission line is connected to the matching element can have a wide band and low loss.

In the invention, it is preferable that the first dielectric plate and the second dielectric plate have a relative dielectric constant in the range of 7 to 10.
According to such a configuration, it is possible to realize a wide band and a low loss, and it is possible to reduce the size of the apparatus.

In the invention, it is preferable that the short-circuit plate, the planar transmission line, the matching element, and the first dielectric plate are formed of a multilayer substrate having three or more layers.
  According to such a configuration, a target configuration can be easily obtained by using a multilayer substrate.

Further, the invention is characterized in that a matching circuit is loaded on a part of the planar transmission line.
According to such a configuration, impedance matching can be easily performed.

  According to the present invention, it is possible to provide a planar transmission line / waveguide converter having a wide band and low loss.

It is a perspective view which shows the example of a basic composition of embodiment of this invention. It is a figure which shows the detailed structural example of embodiment shown in FIG. It is a figure which shows the electric field distribution of embodiment shown in FIG. It is a figure which shows the electric field distribution of the conventional structural example. It is a figure which shows the transmission characteristic of embodiment shown in FIG. 1, and a prior art example. It is a figure which shows the reflection characteristic of embodiment shown in FIG. 1, and a prior art example. It is a perspective view which shows the structural example of 1st Embodiment of this invention. It is sectional drawing of 1st Embodiment shown in FIG. It is a figure which shows the relationship between L and T of 1st Embodiment shown in FIG. 7, and a specific band. It is a perspective view which shows the structural example of 2nd Embodiment of this invention. It is sectional drawing of 2nd Embodiment shown in FIG. It is a perspective view which shows the structural example of 3rd Embodiment of this invention. It is sectional drawing of 3rd Embodiment shown in FIG. It is a perspective view which shows the structural example of 4th Embodiment of this invention. It is a figure which shows the internal structure of 4th Embodiment shown in FIG. It is sectional drawing of 4th Embodiment shown in FIG. It is a figure which shows the electric field distribution of embodiment shown in FIG. It is a figure which shows the electric field distribution of the conventional structural example. It is a figure which shows the transmission characteristic of 4th Embodiment shown in FIG. 14, and a prior art example. It is a figure which shows the reflection characteristic of 4th Embodiment shown in FIG. 14, and a prior art example.

  Next, an embodiment of the present invention will be described.

(A) Description of Basic Configuration of Embodiment FIG. 1 is a diagram for explaining a basic configuration of an embodiment of the present invention. As shown in FIG. 1, the basic configuration of the embodiment of the present invention includes a waveguide 200, a dielectric plate 210, a conductor plate 220, a dielectric plate 230, and a conductor plate 240. The conductor plate 220 (including a matching element 222 to be described later), the dielectric plate 230, and the conductor plate 240 (including a planar transmission line 242 to be described later) are stacked in this order to constitute one stacked substrate. Here, the waveguide 200 is configured by forming a waveguide 202 in the center of a metal member 201 having a rectangular parallelepiped shape. The dielectric plate 210 is disposed in the waveguide 202 of the waveguide 200 as will be described later. The conductor plate 220 is made of a conductive plate-like member and has an opening 221 at the center. A matching element 222 made of a conductive plate member is disposed in the opening 221. A plurality of through holes 223 are formed around the opening 221. The dielectric plate 230 is made of a plate-like dielectric, and a plurality of through holes 231 are formed at positions corresponding to the plurality of through holes 223 formed in the conductor plate 220. The conductor plate 240 functions as a short-circuit plate, and is composed of a conductive plate-like member having a notch 240a formed in the center. A planar transmission line 242 having a linear shape is disposed inside the notch 240a. A plurality of through holes 241 are formed on the inner periphery of the conductor plate 240.

  FIG. 2 is a diagram illustrating a detailed configuration example of each unit of the basic configuration of the embodiment illustrated in FIG. 1. FIG. 2A shows a detailed configuration example of the conductor plate 240 arranged on the dielectric plate 230 shown in FIG. In this example, the dielectric constant of the dielectric plate 230 is εr, the diameter of the through hole 241 formed in the conductor plate 240 is φ, the interval between adjacent through holes 241 is d, and the planar transmission line 242 The width in the short direction is wt, and the distance between the planar transmission line 242 and the notch 240a is g.

  FIG. 2B shows a detailed configuration example of the conductor plate 220 shown in FIG. In this example, the length in the longitudinal direction of the opening 221 formed in the conductor plate 220 is a, and the length in the short direction is b. The width of the matching element 222 arranged in the opening 221 is w1 in the horizontal direction (horizontal direction in FIG. 2) and w2 in the vertical direction (vertical direction in FIG. 2).

  FIG. 2C shows an example of a cross-sectional view when the basic configuration of the embodiment shown in FIG. 1 is cut along AA shown in FIG. In this example, the conductor plate 220 and the conductor plate 240 are electrically connected by a plurality of through holes 223, 231, and 241. As a result, the conductor plate 220 and the conductor plate 240 have the same potential. Further, the thickness of the dielectric plate 230 is t, the length in which the planar transmission line 242 and the matching element 222 overlap is ρ, the thickness of the dielectric plate 210 is T, The interval between the matching elements 222 is L. 1 and 2 are schematic views for facilitating understanding, and the dimensions of each part are different from actual ones.

(B) Description of Operation of Basic Configuration of Embodiment Next, the operation of the basic configuration shown in FIGS. 1 and 2 will be described. The characteristics when the dimensions of each part of the basic configuration of the present invention were set as follows were obtained by simulation.

W1: 1.085mm
W2: 1.085mm
ρ: 0.195 mm
wt: 0.27 mm
g: 0.1 mm
t: 0.127 mm
a: 3.1 mm
b: 1.55 mm
φ: 0.2 mm
d: 0.5 mm
T: 0.3 mm
L: 0.1 mm

  FIG. 3 shows the result of setting the parameters as described above and simulating the electric field distribution. Similarly, FIG. 4 shows the result of simulating the electric field distribution when parameters are set and the dielectric plate 210 is excluded.

  3 and 4 both show the electric field distribution on the surface where the matching element 222 is arranged in FIG. From comparison between FIG. 3 and FIG. 4, the electric field strength around the matching element 222 is reduced in this embodiment.

  FIG. 5 is a graph in which the amount of transmission between the waveguide 200 and the planar transmission line 242 is obtained by simulation. In FIG. 5, the solid line represents the transmission characteristics when a dielectric (eg, alumina) having a relative dielectric constant of 9.9 is used as the dielectric plate 210 and the dielectric plate 230 in the basic configuration of the present invention. 1 shows transmission characteristics when a dielectric having a relative dielectric constant of 2.2 is used with respect to the conventional configuration not having the dielectric plate 210 shown in FIG. 1, and a one-dot chain line shows the dielectric shown in FIG. The transmission characteristics in the case where a dielectric having a relative dielectric constant of 9.9 is used with respect to the conventional configuration without the plate 210 are shown. As shown in this figure, when a member such as alumina having a relative dielectric constant of 9.9 is used, the transmission amount which was -1.7 dB in the conventional configuration is improved to -0.5 dB in the present embodiment. be able to. Therefore, in this embodiment, even when a dielectric having a high relative dielectric constant is used, loss can be reduced.

  FIG. 6 is a graph in which the amount of reflection between the waveguide 200 and the planar transmission line 242 is obtained by simulation. In FIG. 6, the solid line shows the reflection characteristics when a dielectric having a relative dielectric constant of 9.9 is used as the dielectric plate 210 and the dielectric plate 230 in the basic configuration of the present invention, and the broken line is shown in FIG. 1 shows a reflection characteristic when a dielectric having a relative dielectric constant of 2.2 is used with respect to the conventional configuration without the dielectric plate 210 shown, and the alternate long and short dash line indicates the conventional configuration without the dielectric plate 210 shown in FIG. The reflection characteristic when a dielectric having a relative dielectric constant of 9.9 is used is shown. As shown in this figure, when a member such as alumina having a relative dielectric constant of 9.9 is used, the ratio band (= bandwidth (reflection amount: -20 dB or less) / (Center frequency) can be improved to 1.5%. For this reason, in this embodiment, even when a dielectric having a high relative dielectric constant is used, it is possible to realize a broadband that is about 4.5 times as large as the conventional one.

As described above, in the basic configuration of the present embodiment, the dielectric plate 210 is disposed on the opposite side of the dielectric plate 230 with the matching element 222 interposed therebetween, so that loss is reduced and the specific band is widened. can do. Further, by forming a gap between the dielectric plate 210 and the matching element 222 and disposing a layer made of air, it is possible to further reduce the loss and further increase the specific band. Further, in the basic configuration of this embodiment, a planar transmission line 242 disposed notches 240a of the conductive plate 240 and the matching element 222, planar transmission line-guiding of the wider band and low loss be placed closer to each other A wave tube converter can be obtained.

  In the above example, the case where T = 0.3 mm and L = 0.1 mm has been described as an example. However, when T = 0.3 mm and L = 0 mm, the specific bandwidth is 0.61%. When T = 0.2 mm and L = 0.2 mm, the specific band is 1.06%, and when T = 0.2 mm and L = 0.3 mm, the specific band is 1.03%. Therefore, even with such a setting, it is possible to realize a low loss and a wide band.

FIG. 7 is an exploded perspective view showing a configuration example of the planar transmission line / waveguide converter according to the first embodiment of the present invention. 8 is a cross-sectional view showing a cross section when the planar transmission line / waveguide converter 1 shown in FIG. 7 is cut along arrows BB. As shown in FIG. 7, the planar transmission line / waveguide converter 1 according to the first embodiment of the present invention includes a waveguide 10, a laminated substrate 20, a metal plate 31 , and a laminated substrate 40. Yes.

  Here, the waveguide 10 is configured by forming a waveguide 12 at the center of a metal member 11 having a rectangular parallelepiped shape. On the upper surface of the waveguide 10 (the upper surface in FIG. 7), the tips of screws 51 and 52 are inserted, and screw holes 13 and 14 for locking these screws 51 and 52 are formed.

  The multilayer substrate 20 has conductor plates 22 and 23 formed on the front (front) surface (upper surface in FIG. 7) and the back surface (lower surface in FIG. 7), respectively. It is constituted by a dielectric plate 21 of about 9.9 alumina. The conductor plate 22 has an opening 22 a having a central portion having the same shape as the waveguide 12. As shown on the right side of FIG. 7, the conductor plate 23 is similarly formed with an opening 23 a having the same shape as the waveguide 12 at the center. The dielectric plate 21 is not formed with an opening. A plurality of through holes 26 are formed around the openings 22a and 23a. The plurality of through holes 26 are formed so as to penetrate the conductor plate 22, the dielectric plate 21, and the conductor plate 23. Screw holes 24 and 25 are formed at positions corresponding to the screw holes 13 and 14 formed in the waveguide 10. The screw holes 24 and 25 are also formed so as to penetrate the conductor plate 22, the dielectric plate 21, and the conductor plate 23.

The metal plate 31 is composed of a conductive plate member. An opening 32 having a shape corresponding to the waveguide 12 of the waveguide 10 is formed at the center of the metal plate 31 . Screw holes 33 and 34 are formed at positions corresponding to the screw holes 13 and 14 formed in the waveguide 10.

  The multilayer substrate 40 is made of alumina having conductor plates 42 and 43 formed on the front surface (upper surface in FIG. 7) and the back surface (lower surface in FIG. 7), respectively, for example, having a relative dielectric constant of about 9.9. Of the dielectric plate 41. The conductor plate 42 is configured such that the width in the X direction is narrower than that of the dielectric plate 41, and a cut portion 42a is formed at the center. A planar transmission line 46 made of a conductive metal member having a rectangular shape smaller than the shape of the cut portion 42a is disposed in the cut portion 42a. As shown on the right side of FIG. 7, the conductor plate 43 has an opening 43 a having the same shape as the waveguide 12. A matching element 48 made of a conductive metal member having an area smaller than that of the opening 43a is disposed at the center of the opening 43a. A plurality of through holes 47 are formed around the opening 43a. The plurality of through holes 47 are formed so as to penetrate the conductor plate 42, the dielectric plate 41, and the conductor plate 43. Screw holes 44 and 45 are formed at positions corresponding to the screw holes 13 and 14 formed in the waveguide 10. The screw holes 44 and 45 are also formed so as to penetrate the conductor plate 42, the dielectric plate 41, and the conductor plate 43.

The laminated substrate 20, the metal plate 31 , and the laminated substrate 40 having the above-described configuration are screwed to the waveguide 10 by screws 51 and 52 in a state of being stacked in this order.

As a result, as shown in FIG. 8, the laminated substrate 20, the metal plate 31 , and the laminated substrate 40 are arranged on the upper side of the waveguide 10 (upper side in FIG. 8). The conductor plates 22 and 23 of the multilayer substrate 20 are arranged so that the openings 22a and 23a and the waveguide 12 coincide. Further, the metal plate 31 and the laminated substrate 40 are also arranged so that the opening 32 and the opening 43 a coincide with the waveguide 12. A dielectric plate 21 is disposed at the end of the waveguide 12, and a dielectric plate 41 is disposed behind the dielectric plate 21. A matching element 48 is disposed on the back side of the dielectric plate 41 (the lower side in FIG. 8). A plurality of through holes 26 formed in the laminated substrate 20 electrically connect the conductor plates 22 and 23. A plurality of through holes 47 formed in the laminated substrate 40 electrically connect the conductor plates 42 and 43. The thickness of the dielectric plate 21 is T, and the distance between the matching element 48 and the dielectric plate 21 is L. 7 and 8 are schematic views for facilitating understanding, and the dimensions of each part are different from actual ones.

(D) Description of Operation of First Embodiment Next, the operation of the first embodiment shown in FIG. 7 will be described. In the first embodiment, when parameters are set as in the basic configuration, and when T = 0.3 mm and L = 0.1 mm, the electric field distribution is in the same state as in FIG. Further, the transmission characteristics and the reflection characteristics are the same as the solid lines shown in FIGS . Also in the case of the first embodiment, it is possible to realize a wide band and a low loss.

  9 shows the first embodiment shown in FIG. 7, in which the thickness t of the dielectric plate 41 is 0.1 mm, the thickness T of the dielectric plate 21 to be loaded, and the distance between the matching element 48 and the dielectric plate 21 It is a figure which shows the change of a ratio band at the time of changing T and L when it is set to L. In this figure, the column direction indicates T, and in this example, T = 0, 0.1, 0.2, 0.3, and 0.4 are shown. The row direction indicates L. In this example, L = 0, 0.1, 0.2, and 0.3 are shown. T = 0 indicates a case where the dielectric plate 21 is not provided, and shows a conventional configuration. In this example, the ratio band when T = 0 is 0.61%. The hatched area in the figure indicates that the characteristics are improved as compared with the ratio band 0.61% of the conventional configuration.

When the above results are expressed using a variable c (= 0.1 mm), it has become clear that the effect can be obtained within the following range.
(1) When L = 0, T = 3c
(2) When L = c, c ≦ T ≦ 3c
(3) When L = 2c, T = 2c
(4) When L = 3c, T = 2c

In addition, when T is used as a reference, the effect is obtained in the following range.
(5) In the case of T = 2c, 1 c ≦ L ≦ 3 c

From the above, the dielectric plate 21 is disposed on the opposite side of the dielectric plate 41 with the matching element 48 interposed therebetween, so that loss can be reduced and the specific band can be widened. Further, by forming a gap between the dielectric plate 21 and the matching element 48 and disposing a layer of air, it is possible to further reduce the loss and further increase the specific band. Further, by setting the distance L between the matching element 48 and the dielectric plate 21 and the thickness T of the dielectric plate 21 to have a predetermined relationship, the specific band can be widened. Further , the planar transmission line 46 and the matching element 48 arranged in the notch 42a of the conductor plate 42 are electromagnetically coupled to each other by being arranged close to each other, and the dielectric plate 41 has a thickness greater than that of the dielectric plate 41. By arranging the body plate 21, it is possible to obtain a planar transmission line / waveguide converter with a wide band and low loss.

(E) Description of Second Embodiment FIG. 10 is a diagram illustrating a configuration example of the second embodiment of the present invention. In FIG. 10, parts corresponding to those in the first embodiment shown in FIG. In the second embodiment shown in FIG. 10, compared with FIG. 7, the laminated substrate 20 and the metal plate 31 are excluded, and laminated substrates 70, 80, and 90 are added. Further, the conductor plate 43 is excluded from the back surface of the multilayer substrate 40, and only the matching element 48 is left. Furthermore, in the embodiment shown in FIG. 12, the dielectric plates 41, 71, 81, 91 are configured by a plate-like member such as LTCC (Low Temperature Co-fired Ceramics).

  Here, in the multilayer substrate 70, conductor plates 72 and 73 are respectively formed on the front and back surfaces of the dielectric plate 71, and an opening 74 having a shape corresponding to the waveguide 12 is formed at the center. It is formed so as to penetrate the plate 71. A plurality of through holes 77 and screw holes 75 and 76 are formed around the opening 74.

  In the laminated substrate 80, a conductor plate 82 is laminated on the surface of a dielectric plate 81. An opening 82 a having a shape corresponding to the waveguide 12 is formed in the center of the conductor plate 82. The dielectric plate 81 has no opening. A plurality of through holes 85 and screw holes 83 and 84 are formed around the opening 82a.

  In the multilayer substrate 90, a conductor plate 92 is laminated on the surface of the dielectric plate 91, and an opening 93 having a shape corresponding to the waveguide 12 is formed in the center so as to penetrate the conductor plate 92 and the dielectric plate 91. Yes. A plurality of through holes 96 and screw holes 94 and 95 are formed around the opening 93.

  The laminated substrates 70 to 90 and the laminated substrate 40 having the above-described configuration are screwed to the waveguide 10 by screws 51 and 52 in a state of being stacked in this order.

  As a result, as shown in FIG. 11, the laminated substrates 70 to 90 and the laminated substrate 40 are arranged on the upper side of the waveguide 10 (upper side of FIG. 11). 11 is a cross-sectional view showing a cross section when the planar transmission line / waveguide converter 1 shown in FIG. 10 is cut by arrows CC. The laminated substrate 70 is disposed so that the opening 74 and the waveguide 12 of the waveguide 10 coincide. The laminated substrate 80 is disposed so that the opening 82a and the waveguide 12 are aligned, and the laminated substrate 90 is disposed so that the opening 93 and the waveguide 12 of the waveguide 10 are aligned. A dielectric plate 81 is disposed at the end of the waveguide 12, and a dielectric plate 41 is disposed behind the dielectric plate 81. A matching element 48 is disposed on the back side of the dielectric plate 41 (the lower side in FIG. 11). A plurality of through holes 77, 85, 96 formed in the multilayer substrates 70, 80, 90 electrically connect the conductor plates 73, 72, 82, 92. The plurality of through holes 77, 85, 96, 47 formed in the multilayer substrates 70, 80, 90, 40 electrically connect the conductor plates 73, 72, 82, 92, 42. The thickness of the dielectric plate 81 is T, and the interval between the matching element 48 and the dielectric plate 81 is L. 10 and 11 are schematic views for facilitating understanding, and the dimensions of each part are different from the actual ones.

In the second embodiment of the present invention as described above, the dielectric plate 81 is arranged on the opposite side of the dielectric plate 41 with the matching element 48 sandwiched between the basic configuration and the first embodiment described above. As a result , the loss can be reduced and the specific band can be widened. Further, by forming a gap between the dielectric plate 81 and the matching element 48 and disposing a layer made of air, it is possible to further reduce the loss and further increase the specific band. In addition , the planar transmission line 46 and the matching element 48 disposed in the notch 42a of the conductor plate 42 are disposed close to each other so as to be electromagnetically coupled to each other, and the dielectric plate 41 has a thickness greater than that of the dielectric plate 41. By disposing the body plate 81, it is possible to obtain a planar transmission line / waveguide converter with a wide band and low loss.

(F) Description of Third Embodiment FIG. 12 is a diagram illustrating a configuration example of a third embodiment of the present invention. In FIG. 12, parts corresponding to those of the first embodiment shown in FIG. In the third embodiment shown in FIG. 12, compared with FIG. 7, the planar transmission line 46 arranged on the multilayer substrate 20 is replaced with a planar transmission line 49. Other configurations are the same as those in FIG. Here, the planar transmission line 49 has a matching circuit 49a whose width is partially enlarged. Impedance matching can be achieved by providing such a matching circuit 49a.

FIG. 13: is sectional drawing at the time of cut | disconnecting 3rd Embodiment shown in FIG. 12 by DD. As shown in FIG. 13, the laminated substrate 20, the metal plate 31 , and the laminated substrate 40 are disposed on the upper side of the waveguide 10 (upper side in FIG. 13). The laminated substrate 20 is disposed so that the openings 22a and 23a and the waveguide 12 of the waveguide 10 coincide. Further, the metal plate 31 and the laminated substrate 40 are also arranged so that the opening 32 and the opening 43 a coincide with the waveguide 12 of the waveguide 10. A dielectric plate 21 is disposed at the end of the waveguide 12, and a dielectric plate 41 is disposed behind the dielectric plate 21. A matching element 48 is arranged on the back side (lower side in FIG. 13) of the dielectric plate 41. A plurality of through holes 26 formed in the laminated substrate 20 electrically connect the conductor plates 22 and 23. A plurality of through holes 47 formed in the laminated substrate 40 electrically connect the conductor plates 42 and 43. The thickness of the dielectric plate 21 is T, and the distance between the matching element 48 and the dielectric plate 21 is L. 12 and 13 are schematic views for facilitating understanding, and the dimensions of each part are different from the actual ones.

In the third embodiment of the present invention as described above, the dielectric plate 21 is arranged on the opposite side of the dielectric plate 41 with the matching element 48 sandwiched between the basic configuration and the first and second embodiments described above. By doing so , the loss can be reduced and the specific band can be widened. Further, by forming a gap between the dielectric plate 21 and the matching element 48 and disposing a layer of air, it is possible to further reduce the loss and further increase the specific band. Further , the planar transmission line 49 and the matching element 48 arranged in the cut 42a of the conductor plate 42 are electromagnetically coupled to each other by being arranged close to each other, and a dielectric having a thickness equal to or greater than that of the dielectric plate 41. By arranging the body plate 21, it is possible to obtain a planar transmission line / waveguide converter with a wide band and low loss.

(F) Explanation of 4th Embodiment FIG. 14: is a figure which shows the structural example of 4th Embodiment of this invention. The fourth embodiment is an embodiment using a patch antenna, and includes a waveguide 110 and a laminated substrate 120. Here, the waveguide 110 is constituted by a rectangular parallelepiped metal member 111 having a waveguide 112 inside. In the multilayer substrate 120, the matching element 123 is disposed in the central portion on the upper surface (the upper side in FIG. 14) of the dielectric plate 121, and the conductor plate 122 is disposed so as to surround the periphery thereof. A planar transmission line 124 is connected to the matching element 123. In addition, a conductor plate 125 is formed on the entire surface of the lower side of the multilayer substrate 120 (lower side in FIG. 14). The conductor plate 122 and the conductor plate 125 are connected to each other through a through hole (not shown).

  FIG. 15 shows the internal structure when cut by EE shown in FIG. As shown in this figure, a dielectric plate 130 is disposed at the bottom of the waveguide 112 of the waveguide 110. The dielectric plate 130 is made of a dielectric (for example, alumina) having a relative dielectric constant of 9.9, for example.

  FIG. 16 is a cross-sectional view taken along the line EE shown in FIG. As shown in this figure, the dielectric plate 130 is disposed at a position separated from the matching element 123 by a distance L. The thickness of the dielectric plate 130 is T. The conductor plate 122 and the conductor plate 125 are electrically connected by a plurality of through holes 126. As a result, the conductor plate 122 and the conductor plate 125 have the same potential. 14 to 16 are schematic diagrams for facilitating understanding, and the dimensions of each part are different from the actual ones.

  FIG. 17 is a diagram illustrating a result of electric field distribution simulation according to the fourth embodiment. FIG. 18 is a diagram showing the result of electric field distribution simulation when the dielectric plate 130 is excluded from the configuration shown in FIG. 17 and 18 both show the electric field distribution on the surface where the matching element 123 is arranged. From the comparison between FIG. 17 and FIG. 18, in the fourth embodiment, the electric field strength is low.

  FIG. 19 is a diagram illustrating the transmission characteristics of the fourth embodiment. In this figure, the solid line shows the transmission characteristic of the fourth embodiment, and the broken line shows the transmission characteristic of the conventional technique (when the dielectric plate 130 is excluded). As shown in this figure, in the fourth embodiment, the transmission characteristics can be improved by about 1 dB compared with the case where the dielectric plate 130 is not used.

  FIG. 20 is a diagram illustrating the reflection characteristics of the fourth embodiment. In this figure, the solid line shows the reflection characteristic of the fourth embodiment, and the broken line shows the reflection characteristic of the prior art. As shown in this figure, in the fourth embodiment, the reflection characteristic can be broadened by about twice as compared with the case where the dielectric plate 130 is not used.

As described above, even in the case of the fourth embodiment, similarly to the basic configuration described above and the first, second, and third embodiments, the matching element 123 is sandwiched on the opposite side of the dielectric plate 121. The dielectric plate 130 is arranged . As a result, the loss can be reduced and the specific band can be widened. Further, by forming a gap between the dielectric plate 130 and the matching element 123 and disposing a layer made of air, it is possible to further reduce the loss and further increase the specific band.

(E) Description of Modified Embodiment Each of the above embodiments is an example, and it is needless to say that the present invention is not limited to the case described above. For example, in the basic embodiment, the dielectric plate 210 is made of alumina, but other dielectric materials may be used. Further, although the space between the dielectric plate 210 and the dielectric plate 230 is filled with air, it may be filled with a gas other than air (for example, a rare gas). Of course, a liquid dielectric may be filled.

  Moreover, although the dimension of each part was shown in the basic composition, this dimension is an example, Comprising: This invention is not limited only to these numerical values, You may make it change a dimension according to the objective.

  Further, in the first embodiment, as shown in FIG. 9, the change in the ratio band when the thickness T of the dielectric plate 21 and the distance L between the matching element 48 and the dielectric plate 21 are changed is examined. The result of FIG. 9 is an example in which alumina is used as the dielectric plate 21 and the above-described dimensions are used. Therefore, when other dimensions and dielectrics are used, other results may be obtained. Of course there is.

DESCRIPTION OF SYMBOLS 1 Planar transmission line and waveguide converter 10,110 Waveguide 12,112 Waveguide 20,40,70,80,90,120 Laminated substrate 21,41,71,81,91,121,130 Dielectric board 30 Metal plate 43, 72, 73, 82, 92, 125 Conductor plate 42, 122, 240 Conductor plate (short circuit plate)
46,124 Planar transmission line 48,123 Matching element

Claims (6)

In a planar transmission line / waveguide converter capable of mutually converting power transmitted by a planar transmission line and power transmitted by a waveguide,
A short-circuit plate disposed substantially parallel to the opening surface of one opening of the waveguide;
A planar transmission line having an end disposed in the opening;
A matching element that is arranged in a direction parallel to the short-circuit plate and spaced apart in the axial direction of the waveguide by a predetermined distance from the short-circuit plate, and electromagnetically coupled to the planar transmission line;
A first dielectric plate disposed between the shorting plate and the matching element;
A second dielectric plate disposed on the opposite side of the first dielectric plate across the matching element and spaced apart from the matching element by a predetermined distance in the axial direction of the waveguide When,
At least one of a metal plate and a dielectric plate interposed between the first and second dielectric plates and having an opening corresponding to the opening of the waveguide;
A planar transmission line / waveguide converter characterized by comprising: A cut is formed in a part of the short-circuit plate,
The planar transmission line / waveguide converter according to claim 1, wherein an end of the planar transmission line is disposed in the cut.   The planar transmission line / waveguide converter according to claim 1, wherein an end of the planar transmission line is connected to the matching element. 4. The planar transmission line according to claim 1, wherein the first dielectric plate and the second dielectric plate have a relative dielectric constant in the range of 7 to 10. 5. -Waveguide converter. The said short circuit board, the said plane transmission line, the said matching element, and the said 1st dielectric board are comprised by the multilayer board | substrate of 3 or more layers, The any one of Claims 1 thru | or 4 characterized by the above-mentioned. The planar transmission line / waveguide converter described. The planar transmission line / waveguide converter according to claim 1, wherein a matching circuit is loaded on a part of the planar transmission line.

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