JP5721458B2 - Connection structure between high-frequency circuit and slot - Google Patents

Description

  The present invention relates to a connection structure between a slot and a high-frequency circuit that are frequently used in a high-frequency band such as a millimeter wave, and particularly relates to a connection structure to a differential terminal using a conducting wire such as a bonding wire.

  Conventionally, a connection structure between a differential line and a waveguide via a slot is known. For example, a structure has been proposed in which a waveguide is disposed under a substrate on which a differential line is formed, and an end portion of the differential line and both sides of the central portion of the slot are connected by via holes (for example, Patent Documents). 1).

JP 2009-33526 A

In recent years, differential terminals for inputting / outputting differential signals have come to be used also in monolithic microwave integrated circuits (MMICs). However, when the MMIC having the differential terminal on the upper surface and the slot are connected using the structure proposed in Patent Document 1, it is necessary to connect the differential line and the differential terminal with a bonding wire. There was a problem that became complicated.

  The present invention has been devised in view of such problems in the prior art, and an object thereof is to provide a connection structure between a high-frequency circuit and a slot that has a simple structure and can transmit a differential signal. There is to do.

The connection structure between the high-frequency circuit and the slot according to the present invention includes a slot formed in a planar conductor and short-circuited at both ends , a high-frequency circuit having a pair of terminals composed of first and second terminals, and a differential signal. And the first and second conductive wires connecting the slot and the high-frequency circuit, and the pair of terminals are arranged at a distance from the slot in the length direction of the slot, One end of the first conductor is connected to the first terminal, one end of the second conductor is connected to the second terminal, and the other of the first and second conductors The end is connected to the planar conductor at a position opposite to the pair of terminals with respect to the center in the length direction of the slot and sandwiching the slot in the width direction of the slot. With what That.

  Further, according to the connection structure between the high frequency circuit and the slot of the present invention, in the connection structure between the high frequency circuit and the slot, the first and second conductive wires are arranged so as not to cross over the slot. It is characterized by this.

  Crossing the slot means crossing the slot in the width direction of the slot (including crossing the slot in the width direction obliquely), and when the slot is rectangular, from the normal direction at the center of gravity of the slot. When viewed, it means intersecting with both of the two long sides of the slot. The planar conductor includes both a planar conductor and a curved conductor.

  According to the present invention, it is possible to obtain a connection structure between a high-frequency circuit and a slot that can transmit differential signals satisfactorily.

(A) is a perspective view which shows typically the connection structure of the high frequency circuit and slot of the 1st example of embodiment of this invention, (b) is the connection of the high frequency circuit and slot shown to (a). It is a top view which shows a structure typically. (A) is a perspective view which shows typically the connection structure of the high frequency circuit and slot of the 2nd example of embodiment of this invention, (b) is the connection of the high frequency circuit and slot shown to (a). It is a top view which shows a structure typically. (A) is a perspective view which shows typically the connection structure of the high frequency circuit and slot of the 3rd example of embodiment of this invention, (b) is the connection of the high frequency circuit and slot shown to (a). It is a top view which shows a structure typically. It is a graph which shows the electrical property of the connection structure of the high frequency circuit of the 2nd example of embodiment of this invention, and a slot. It is a graph which shows the electrical property of the connection structure of the high frequency circuit of the 3rd example of embodiment of this invention, and a slot.

  Hereinafter, a connection structure between a high-frequency circuit and a slot according to the present invention will be described in detail with reference to the accompanying drawings.

(First example of embodiment)
FIG. 1A is a perspective view schematically showing a connection structure between a high frequency circuit and a slot according to a first example of the embodiment of the present invention, and FIG. 1B is a perspective view showing the high frequency circuit and the slot shown in FIG. It is a top view which shows typically the connection structure of these.

  As shown in FIG. 1, the connection structure between the high-frequency circuit and the slot of this example includes a planar conductor 11, a slot 12, a first conductor 31, a second conductor 32, and a high-frequency component 20. ing. The slot 12 is formed in a planar conductor 11 that is planar.

  The high frequency component 20 is disposed on the planar conductor 11 and incorporates a high frequency circuit. The high-frequency circuit built in the high-frequency component 20 has a pair of terminals including a first terminal 21 and a second terminal 22. The first terminal 21 and the second terminal 22 are for performing at least one of differential signal input and output, and are disposed on the upper surface of the high-frequency component 20. The high-frequency component 20 is disposed at a distance from the slot 12 in the length direction of the slot 12. Therefore, the pair of terminals are arranged at a distance from the slot 12 in the length direction of the slot 12.

  The first conducting wire 31 and the second conducting wire 32 transmit a differential signal and connect the slot 12 and the high frequency circuit built in the high frequency component 20. One end of the first conducting wire 31 is connected to the first terminal 21, and one end of the second conducting wire 32 is connected to the second terminal 22. The other ends of the first conductor 31 and the second conductor 32 are opposite to the pair of terminals (the + x side in the figure) with respect to the center in the length direction of the slot 12 (the x direction in the figure), and The slot 12 is connected to the planar conductor 11 at a position sandwiching the slot 12 in the width direction of the slot 12 (y direction in the figure). The lengths of the first conductor 31 and the second conductor 32 are set to approximately ½ of the wavelength of the signal to be transmitted, and the length of the slot 12 is also approximately 1 / wavelength of the signal to be transmitted. 2 is set. As a result, good impedance matching is realized.

According to the connection structure of the high-frequency circuit and the slot of this example having such a configuration, the high-frequency circuit built in the high-frequency component 20 and the slot 12 can be connected well. This mechanism can be estimated as follows. That is, the direction of the electric field between the first conductor 31 and the second conductor 32 is substantially horizontal (y direction in the figure) in the vicinity of the first and second terminals 21 and 22. Thereafter, as the slot 12 is approached, the component in the vertical direction (z-axis direction in the figure) gradually increases, and the coupling with the slot 12 becomes stronger. At this time, the other ends of the first conducting wire 31 and the second conducting wire 32 are connected to the planar conductor 11 on the side opposite to the pair of terminals with respect to the center in the length direction (x direction in the figure) of the slot 12. This is considered to be because it is possible to sufficiently secure the coupling with the slot 12 and to prevent the coupling with the planar conductor 11 in the region where the slot 12 is not formed.

  When the other ends of the first conducting wire 31 and the second conducting wire 32 are connected to the planar conductor 11 at the center in the length direction of the slot 12, the high frequency circuit and the slot built in the high frequency component 20 are used. As a result of the study by the present inventor, it has been found that the connection with 12 is not possible. This is considered to be because the coupling with the planar conductor 11 becomes stronger before the coupling with the slot 12 as the first and second conducting wires 31 and 32 approach the planar conductor 11.

  In addition, according to the connection structure between the high-frequency circuit and the slot in this example, the first and second conducting wires 31 and 32 are arranged so as not to cross the slot 12. The connection can be made even better. This is considered to be because the first and second conducting wires 31 and 32 are prevented from being coupled to the planar conductor 11 on both sides of the slot 12.

  According to the connection structure between the high-frequency circuit and the slot in this example, the high-frequency circuit built in the high-frequency component 20 and the slot 12 can be satisfactorily connected. Therefore, the structure shown in FIG. 1 can function as a slot antenna that radiates electromagnetic waves from the slot 12.

(Second example of embodiment)
FIG. 2A is a perspective view schematically showing a connection structure between a high-frequency circuit and a slot of a second example of the embodiment of the present invention, and FIG. 2B is a perspective view of the high-frequency circuit and the slot shown in FIG. It is a top view which shows typically the connection structure of these. Note that in this example, only differences from the first example of the above-described embodiment will be described, and the same components will be denoted by the same reference numerals and redundant description will be omitted.

  As shown in FIG. 2, the high-frequency circuit and slot connection structure of this example includes a dielectric 41 and a back conductor 42 below the planar conductor 11, and the planar conductor 11, the dielectric 41, and the back A dielectric substrate 40 is formed by the conductor 42.

  In the connection structure of the high-frequency circuit and the slot of this example having such a configuration, the differential signal coupled to the slot 12 enters a parallel plate line sandwiched between the planar conductor 11 and the back conductor 42, The slot 12 spreads radially in the width direction (± y direction in the figure). By forming a plurality of such structures on the dielectric substrate 40, two-dimensional communication is possible.

(Third example of embodiment)
FIG. 3A is a perspective view schematically showing a connection structure between the high-frequency circuit and the slot of the third example of the embodiment of the present invention, and FIG. 3B is a perspective view showing the high-frequency circuit and the slot shown in FIG. It is a top view which shows typically the connection structure of these. Note that in this example, only differences from the first example of the above-described embodiment will be described, and the same components will be denoted by the same reference numerals and redundant description will be omitted.

In the connection structure between the high-frequency circuit and the slot of this example, as shown in FIG.
A waveguide line 50 is formed which becomes the upper tube wall. One end of the waveguide line 50 is short-circuited, and the inside of the waveguide line 50 is filled with a dielectric 51. The high frequency component 20 is mounted on the substrate 61.

  In the connection structure between the high-frequency circuit and the slot of the present example having such a configuration, the differential signal of the high-frequency circuit built in the high-frequency component 20 is satisfactorily connected to the waveguide line through the slot 12. Can do.

(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 first to third examples of the above-described embodiment, the shape of the slot 12 is a rectangle, but any shape may be used as long as it functions as a slot, such as a polygon, an ellipse, a bow tie, A dumbbell type or the like may be used.

  Moreover, although the example in which the planar conductor 11 is a planar conductor has been shown, a curved conductor may be used. For example, a part of a spherical surface or a curved curved conductor may be used.

  Furthermore, the example in which the center of the slot 12 is located at a position away from the center of the pair of terminals 21 and 22 in the y direction in the figure is shown. It doesn't matter.

  Furthermore, although the case where the terminals 21 and 22 are a pair of differential types has been shown, the present invention is not limited to this. For example, a terminal lined up with GSSGSG (G: ground conductor, S: signal line) may be used. In the case of such a structure, the ground terminal can also be used for radiation suppression.

  Furthermore, in the first to second examples of the above-described embodiment, the high-frequency component 20 is formed on the planar conductor 11, but this is not always necessary. For example, the planar conductor 11 may not be provided under the high frequency component 20 and may be formed on an insulator. Further, as in the third example of the embodiment, the substrate on which the high frequency component 20 is mounted and the substrate on which the slot 12 is formed may be separated.

  Furthermore, in the second example of the above-described embodiment, an example is shown in which the slot 12 acts as an antenna and electromagnetic waves are radiated into a parallel plate waveguide formed by the planar conductor 11 and the back conductor 42. However, the present invention is not limited to this. For example, the slot 12 can be used not as an antenna but as a power feeding structure to another antenna. Examples of other antennas include a patch antenna, a dipole antenna, a monopole antenna, an inverted F antenna, a dielectric resonator antenna, a loop antenna, a horn antenna, and an array antenna.

  Furthermore, in the third example of the above-described embodiment, an example in which the waveguide line 50 is connected via the slot 12 is shown, but the present invention is not limited to this. For example, it may be connected to a microstrip line, a coplanar line, a slot line, a laminated waveguide line, or the like.

  A specific example of the connection structure between the high-frequency circuit and the slot of the present invention will be described.

Example 1
The electrical characteristics in the connection structure between the high-frequency circuit and the slot of the second example of the embodiment of the present invention shown in FIG. 2 were calculated by simulation based on electromagnetic field analysis.

As calculation conditions, the size of the slot 12 is 1.5 mm × 0.3 mm, the size of the first and second terminals 21 and 22 is 1.0 mm × 0.8 mm, and the size of the high-frequency component 20 incorporating the high-frequency circuit is 0.5.
mm × 1.0 mm, and the thickness was 0.2 mm. The thickness of the planar conductor 11 and the back conductor 42 was set to 0.01 mm. The dielectric 41 had a thickness of 0.8 mm, a dielectric constant of 4.4, and a dielectric loss tangent of 0.02. The distance in the x direction between the first and second terminals 21 and 22 and the center of the slot 12 is 2.15 mm, and the first and second conductors 31 and 32 have a diameter of 25 μm and a length in the x direction of 2.7 mm. It was. The position where the first and second conducting wires 31 and 32 are connected to the planar conductor 11 is a position moved 0.55 mm from the center in the length direction of the slot 12 in the x direction in the figure.

The first and second terminals 21 and 22 were set as differential ports, and their reflection characteristics (S11) were calculated by simulation. FIG. 4 shows the calculation result. In the graph shown in FIG. 4, the horizontal axis is frequency and the vertical axis is attenuation. The solid line indicates S21, the broken line indicates S22, and the dotted line indicates S11. According to the graph shown in FIG. 4, good reflection characteristics of −30 dB or less are shown in the vicinity of 59 GHz. Also, the frequency with reflection amount less than -10dB is 53.5GHz ~ 66.0GHz
The ratio band (bandwidth / center frequency) is 20.9%. This confirmed the effectiveness of the present invention.

Table 1 shows the positions where the conductors 31 and 32 are connected to the planar conductor 11 in the connection structure between the high-frequency circuit and the slot according to the second example of the embodiment of the present invention shown in FIGS. The change in the ratio band when the positional relationship between the slot 12 and the slot 12 is changed is shown. The positional relationship between the position where the conductors 31 and 32 are connected to the planar conductor 11 and the slot 12 by fixing the positions of the first and second conductors 31 and 32 and moving the slot 12 in the x direction. Changed. The connection positions in the table are positive in the + x direction in the figure with the center position in the longitudinal direction of the slot 12 as the origin. Therefore, when the connection position is 0 mm, it means that the first and second conducting wires 31 and 32 are connected to the planar conductor 11 on both sides of the longitudinal center portion of the slot 12. Further, in this embodiment, the length of the slot 12 in the longitudinal direction is 1.5 mm. Therefore, when the connection position is 0.75 mm, the first and first ends at the end portion in the length direction of the slot 12 (the end portion in the + x direction). This means that the two conducting wires 31 and 32 are connected to the planar conductor 11. Only the connection position is changed, and the other conditions are the same as those described above.

  According to Table 1, when the connection position is -0.25 mm and 0.95 mm, the region of S11 <-10 dB is not obtained. When the connection position is p, it can be seen that good characteristics are obtained in the range of 0.15 ≦ p ≦ 0.75.

Table 2 shows that the slot 12 is rotated with respect to the conducting wires 31 and 32 in the connection structure between the high-frequency circuit and the slot in the second example of the embodiment of the present invention shown in FIGS. 2 (a) and 2 (b). It shows the ratio band (bandwidth / center frequency) when the rotation angle is changed. The first and second conducting wires 31 and 32 are fixed, a line segment connecting the two connection points between the first and second conducting wires 31 and 32 and the planar conductor 11, and the width direction of the slot 12 (in the drawing) The characteristics are shown when the slot 12 is rotated with the intersection with the line segment connecting the centers in the y-axis direction as the center and the z-axis direction in the figure as the rotation axis.

  According to Table 2, the center frequency shifts to the low frequency side as it rotates, and the ratio band tends to narrow gradually. A wide band characteristic is shown up to a rotation angle of 10 °, but the band suddenly narrows from 10 ° to 15 °. When viewed from the z direction, up to 10 °, one or both of the first or second conducting wires 31 and 32 intersect the long side and the short side of the slot 12, but in the case of 15 °, One or both of the first or second conductors 31 and 32 intersect the two long sides of the slot 12 and cross the slot 12. From this, it can be seen that in order to obtain good electrical characteristics, the first and second conducting wires 31 and 32 need to be arranged so as not to cross the slot 12.

(Example 2)
The electrical characteristics in the connection structure between the high-frequency circuit and the slot in the third example of the embodiment of the present invention shown in FIG. 3 were calculated by simulation based on electromagnetic field analysis.

As calculation conditions, the size of the slot 12 is 1.5 mm × 0.3 mm, the size of the first and second terminals 21 and 22 is 1.0 mm × 0.8 mm, and the size of the high-frequency component 20 incorporating the high-frequency circuit is 0.5.
mm × 1.0 mm, and the thickness was 0.2 mm. Further, the thickness of the tube wall of the waveguide line 50 including the planar conductor 11 was set to 0.01 mm. The dielectric 51 had a thickness of 0.8 mm, a dielectric constant of 4.4, and a dielectric loss tangent of 0.02. The distance in the x direction between the first and second terminals 21 and 22 and the center of the slot 12 was 2.15 mm. The first and second conducting wires 31 and 32 had a diameter of 25 μm and a length in the x direction of 2.8 mm. The waveguide line 50 has a width of 1.8 mm and a length in the y direction of 3.0 mm.
The distance between the center of the slot 12 and the short-circuited end of the waveguide line 50 was 0.35 mm. Further, the height in the z direction of the surface of the substrate 61 on which the high-frequency component 20 is mounted and the surface of the planar conductor 11 are matched.

The first and second terminals 21 and 22 are set to the differential port 1 and the open surface of the waveguide line 50 is set to the port 2, and the electrical characteristics are calculated by simulation. FIG. 5 shows the calculation result. According to the graph shown in FIG. 5, the frequency when the reflection amount S11 is −10 dB or less is 58.3 GHz to 71.3 GHz, and the frequency when the reflection amount S22 is −10 dB or less is 56.4 GHz to 73.9 GHz. Therefore, S11
The ratio band where both S22 and S22 are -10 dB or less was 20.0%, confirming the effectiveness of the present invention.

  In the frequency band, the insertion loss S21 has a loss of about -2.3 dB, that is, about 40%, about half of which is loss due to dielectrics and conductors, and the other half is radiation loss. It is considered that this radiation loss can be suppressed by forming a conducting wire that is connected to the planar conductor 11 at both ends and crosses the slot 12 in the air.

11: Planar conductor
12: Slot
21: First terminal
22: Second terminal
31: First conductor
32: Second conductor

Claims (2)

A slot formed in a planar conductor and shorted at both ends ;
A high-frequency circuit having a pair of terminals composed of first and second terminals;
A differential signal is transmitted, the first and second conductors connecting the slot and the high-frequency circuit;
The pair of terminals are arranged at a distance from the slot in the length direction of the slot,
One end of the first conducting wire is connected to the first terminal, and one end of the second conducting wire is connected to the second terminal;
The other end of each of the first and second conducting wires is opposite to the pair of terminals with respect to the center in the length direction of the slot, and at the position sandwiching the slot in the width direction of the slot, the surface A connection structure between a high-frequency circuit and a slot, characterized by being connected to a conductor.   2. The connection structure between a high frequency circuit and a slot according to claim 1, wherein the first and second conducting wires are arranged so as not to cross the slot.

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