JPH06303010A - High frequency transmission line and integrated circuit device using the same, and connceting method for high frequency plane circuit - Google Patents

Abstract

PURPOSE:To reduce the interference between transmission lines or to suppress the reflection loss or the like due discontinuity of a connecting face by adjusting a width of a signal line through which a high frequency signal is sent and a gap between the signal line and a ground conductor so as to make the characteristic impedance of the signal line constant. CONSTITUTION:A strip line region 15 comprising a conventional microstrip line and a characteristic constant line region 16 comprising a high frequency transmission line are provided and a signal is propagated in the direction of the arrow or in its opposite direction. Furthermore, a dielectric board 17 and upper ground conductors 18, 19 are provided and a signal line 20 is formed between the upper ground conductors 18, 19. Through the constitution above, the gap between the line 20 and the conductors 18, 19 is set so that the width of the signal line 20 having a structure of a coplaner guide path is continuously changed and the characteristic impedance is made constant according to the change. Thus, the high frequency transmission line in which the adjacent signal lines are less affected with each other is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency transmission line for transmitting a high-frequency signal (1 GHz or more) or a broadband signal used for communication, broadcasting, etc., and an integrated circuit device using the high-frequency transmission line, It also relates to a method of connecting a high frequency plane circuit.

[0002]

2. Description of the Related Art In recent years, a substrate having a low dielectric constant on which a semiconductor integrated circuit can be directly mounted has been put on the market. When a microstrip line is constructed with such a low dielectric constant substrate, the width of the signal line for input / output becomes wider than that of a ceramic substrate that has been mainly used conventionally.

Conventionally, for example, when a semiconductor integrated circuit 1 having three ports is mounted on a dielectric substrate 2 having a low dielectric constant as shown in FIG.
When the width of 5 becomes equal to or larger than the size of the semiconductor integrated circuit 1, the transmission line connecting the input terminal A and the output terminal B and the transmission line connecting the input terminal A and the output terminal C influence each other and are separated. As a result, the original characteristics of the semiconductor integrated circuit 1 cannot be fully exhibited. In FIG. 9, 6 is a ground conductor on which the semiconductor integrated circuit 1 is mounted, 7
Is a bond wire that connects each port of the semiconductor integrated circuit 1 to each of the signal lines 3 to 5.

Further, as shown in FIG. 10, when connecting high frequency planar circuits formed on two dielectric substrates 8 and 9 having different relative permittivities or different thicknesses,
When the signal lines 10 and 11 have different widths,
The connection surface of both signal lines 10 and 11 becomes discontinuous, and the discontinuity at the connection surface causes reflection loss. In FIG. 10, D is a connecting surface of the two dielectric substrates 8 and 9, and E and F are input / output terminals of the high frequency flat circuit provided on the dielectric substrates 8 and 9.

[0005]

As described above, in the conventional high-frequency transmission line as described above, when the semiconductor integrated circuit 1 is mounted on the dielectric substrate 2 having a low dielectric constant, the signal lines 3 to 5 are used. When the width becomes equal to or larger than the size of the semiconductor integrated circuit 1, adjacent signal lines influence each other and the degree of separation is reduced, and the original characteristics of the semiconductor integrated circuit 1 can be sufficiently exhibited. There was a problem of disappearing.

Further, when a plurality of high-frequency plane circuits formed on dielectric substrates having different relative permittivities or thicknesses are connected to each other, when the widths of signal lines connected to each other are different from each other, discontinuity on the connection surface is caused. There is a problem that reflection loss occurs due to the sex.

Further, with the recent trend toward portable and low-cost communication equipment, broadcasting equipment, etc., there is an increasing demand for further miniaturization. However, due to the discontinuity in the connection surface, There is also a problem that the deterioration is a major obstacle to downsizing of this kind of communication equipment.

The present invention has been made in view of the above conventional problems, and the width of a signal line through which a high frequency signal is transmitted and the gap between the signal line and the ground conductor are adjusted to adjust the signal line. Provided are a high-frequency transmission line, an integrated circuit device, and a method of connecting a high-frequency plane circuit, which can reduce interference between transmission lines or suppress reflection loss due to discontinuity of a connection surface by making a characteristic impedance constant or almost constant The purpose is to do.

[0009]

The present invention has a structure of a coplanar waveguide in order to solve the above-mentioned problems and the like and to achieve the above-mentioned object, and continuously changes the width of the signal line thereof. In addition, the gap distance between the signal line and the ground conductor is set so that the characteristic impedance of the signal line becomes constant according to the change.

The gap spacing with respect to the change in the width of the signal line can be continuously changed linearly with respect to the change in the width of the signal line so that the characteristic impedance of the signal line is approximately constant.

Further, a high frequency semiconductor integrated circuit is mounted on a dielectric substrate having a high frequency transmission line having a coplanar waveguide structure, and the width of an input / output signal line to / from this high frequency semiconductor integrated circuit is continuously changed. In addition, the gap distance between the signal line and the ground conductor is set so that the characteristic impedance of the signal line becomes constant according to the change.

Further, a plurality of dielectric substrates having different relative permittivities or different thicknesses are connected on the same plane, and a signal line of a high frequency plane circuit having a structure of a coplanar waveguide formed on these dielectric substrates is provided. The width of the signal line is continuously changed, and the gap between the signal line and the ground conductor is set so that the characteristic impedance of the signal line becomes constant according to the change.

[0013]

According to the present invention, the width of the signal line having the structure of the coplanar waveguide is continuously changed and the characteristic impedance is kept constant according to the change of the signal line. Since the gap distance between the line and the ground conductor is set, a high-frequency transmission line in which adjacent signal lines are less likely to influence each other can be obtained.

Since the change in the width of the signal line continuously changes in a polygonal line and the characteristic of the signal line is approximately constant, adjacent signal lines are less likely to influence each other. It is possible to simplify the manufacture of the high frequency transmission line.

Further, by mounting the high frequency semiconductor integrated circuit on the high frequency transmission line, even when the width of the signal line connected to each port becomes equal to or larger than the size of the semiconductor integrated circuit, the adjacent transmission lines. Are less likely to affect each other to reduce the degree of isolation of the semiconductor integrated circuit, and the original characteristics of the semiconductor integrated circuit can be fully exhibited, which can contribute to portability and miniaturization of various electronic devices. An integrated circuit device is obtained.

Further, when a plurality of dielectric substrates having different relative permittivities or thicknesses are connected on the same plane, reflection loss due to discontinuity at the connecting surfaces is suppressed, and the dielectric substrates are formed on those dielectric substrates. It is possible to efficiently connect the generated high-frequency planar circuits to each other.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view of a high frequency transmission line showing an embodiment of the present invention. In the figure, reference numeral 15 is a strip line region formed of a normal microstrip line, and 16 is a constant characteristic line region formed of a high-frequency transmission line according to the present invention. A signal travels in the direction of the arrow or in the opposite direction. In FIG. 1, 17 is a dielectric substrate, 18 and 19 are upper ground conductors, and a signal line 20 is formed between these upper ground conductors 18 and 19.

FIG. 2 shows the structure of a coplanar waveguide having a lower ground conductor 21. The upper ground conductors 18 and 19 and the signal line 20 are formed on the upper surface of the dielectric substrate 17, and the lower ground conductor 21 is formed on the entire lower surface of the dielectric substrate 17. Through holes 22 pass through the upper ground conductors 18, 19 and the dielectric substrate 17 and the lower ground conductor 21, and the upper ground conductors 18, 19 and the lower ground conductor 21 are connected through holes. .

The signal line 20 includes a strip line region 15
Is formed with a constant width, and the constant characteristic line region 16
In, the taper is linearly tapered from the base end 16a on the strip line region 15 side to the tip 16b on the other side. Two upper ground conductors 1 facing each tapered surface corresponding to the tapered shape of the signal line 20.
8 and 19 are formed by narrowing the gap distance 23 between the signal line 20 and the signal line 20 so that the characteristic impedance of a high-frequency signal or the like passing through the signal line 20 becomes constant from the base end 16a to the tip 16b. ing. That is, the end surfaces of the upper ground conductors 18 and 19 on the signal line 20 side are formed in a parabolic shape, and the gap distance 23 on the base end 16a side of the constant characteristic line area 16 is the widest, and the gap distance increases toward the tip 16b. 23 is narrowed, and the gap distance 23 is set to be narrowest at the tip 16b.

FIG. 3 shows a lower ground conductor 2 as shown in FIG.
For a transmission line having a coplanar waveguide structure having 1, the width W of the signal line 20 is set to the width G of the gap interval 23.
It is a graph which shows the example of measurement of the characteristic relation of the value divided by and reflection loss (dB). In this actual measurement, one port of the signal line 20 shown in FIG. 2 is terminated with 50Ω, and the other port is excited by a signal source having a signal source impedance of 50Ω. Therefore, FIG. 3 also shows the ratio of the reflected power to the incident power at the excitation port when excited by the signal source having the signal source impedance of 50Ω.

In this case, the fact that the reflection loss is large means that the reflected waves interfere with each other to cause a lossless state. Therefore, if the reflection loss is large, the characteristic impedance of the signal line 20 is large. Therefore, as is clear from FIG. 3, in the transmission line, the reflection loss W becomes maximum.
It can be seen that there is a / G ratio. That is, the signal line width W /
When the ratio of the gap width G is 5, the reflection loss is 30 dB.
When the W / G ratio fluctuates from 5 to either the larger side or the smaller side, the reflection loss decreases with the fluctuation amount. The frequency used in this example is 2 GHz.

This experiment was carried out for different line widths,
An example of the plot summarizing the results is shown in FIG. This Figure 4
Shows the width W of the signal line on the horizontal axis and the gap width G / signal line width W at which the maximum return loss is plotted on the vertical axis, and the relationship between the two is plotted. That is, FIG. 4 shows the relationship between the signal line width W and the gap width G / signal line width W when the signal line width W / gap width G = 5 where the reflection loss is maximum. According to FIG. 4, for example,
The experimental point S is G when the signal line width W is 0.88 mm.
/ W is 0.195, and it can be seen that when the signal line width W is narrow, the G / W ratio is small, and the G / W ratio increases as the signal line width W increases. Therefore, for an arbitrary signal line width W, G / according to the plot of FIG.
By setting the gap width so as to keep W, the signal line width W can be changed while keeping the characteristic impedance constant.

FIG. 5 shows the case of FIG.
The reflection loss characteristic of the signal line 20 shown in FIG. In this case, the width of the signal line 20 is set so that the tip end 16b is about 1/2 of the base end 16a. The reflection loss obtained by this is about 30 dB within the measurement band, and since the reflection loss hardly occurs, it can be seen that the characteristic impedance is maintained at about 50Ω. Therefore, according to this signal line 20, since the area of the signal line is small and the ground conductors are always present on both sides of the signal line 20, reflection loss is suppressed even when mutual coupling with other peripheral circuits. Can be connected.

FIG. 6 shows another embodiment of the present invention. In this embodiment, the upper ground conductor 24 and the lower ground conductor 25 are connected endlessly to form a wraparound structure, and the gap distance 27 between the signal line 26 and each upper ground conductor 24 is continuously changed in a polygonal line. It is a thing. Figure 6
In, 28 is a dielectric substrate.

In the high frequency transmission line according to the present invention,
When setting the gap width where the characteristic impedance is constant, as shown in this embodiment, the gap interval is not set by continuously changing the width of the signal line 26 with a curve as in the above embodiment. In order to make the characteristic impedance approximately constant by setting an appropriate length linearly and continuously changing the rate of change linearly and setting the gap interval 27 to be gradually narrow. You may form. In this case, if the error of the characteristic impedance is sufficiently small, it is effective also in the electrical characteristics, and the deterioration of the characteristics of the signal to be transmitted can be effectively suppressed as in the above embodiment. Moreover, if the shape of the end surface 24a of the upper ground conductor 24 can be formed to be a straight line like the signal line 26, the processing becomes easy, and therefore, the manufacture of this type of high frequency transmission line is simplified. It

Next, an embodiment in which the high frequency transmission line shown in the above embodiment is used for mounting a high frequency semiconductor integrated circuit will be described. FIG. 7 is an explanatory diagram showing a state in which a high frequency semiconductor integrated circuit 31 is mounted on the dielectric substrate 30 provided with the high frequency transmission line. An upper ground conductor 32 is formed in the center of the upper surface of the dielectric substrate 30, and a high frequency semiconductor integrated circuit 31 is mounted in the center thereof. The high frequency semiconductor integrated circuit 31 has three ports, and a notch 33 having a substantially V shape is formed in the upper ground conductor 32 corresponding to these ports by opening in three directions. And three signal lines 34-36 are formed so that a tip may face in these notches 33.

The signal line 34 has one end connected to the terminal A, and the signal lines 35 and 36 have one end connected to the terminals B and C.
Output lines connected to the respective signal lines 34
To 36 have the same configuration as the signal line 20 shown in the above embodiment. That is, the signal lines 34 to 36 are connected to the terminal A.
The side to which C to C are connected forms an ordinary microstrip line having a uniform line width, and is formed in a taper shape so that the portion entering the notch 33 of the upper ground conductor 32 is tapered. The tip ends of the signal lines 34 to 36 and the ports of the high frequency semiconductor integrated circuit 31 are connected by bond wires 37, respectively. Reference numeral 38 is a through hole that electrically connects the upper ground conductor 32 and the lower ground conductor.

Thus, each of the signal lines 34 to 36 is converted from the microstrip line to the high frequency transmission line according to the present embodiment, and the line width is gradually narrowed toward the high frequency semiconductor integrated circuit 31. The gap distance 39 set between the upper ground conductor 32 and the upper ground conductor 32 is set, for example, according to the plot of FIG. 4 so that the characteristic impedance of the high-frequency signal passing through the signal lines 34 to 36 becomes constant. As a result, the high frequency semiconductor integrated circuit 3
In the vicinity of 1, the line width of each of the signal lines 34 to 36 is equal to or smaller than the size of the high frequency semiconductor integrated circuit 31.
Therefore, the mutual coupling between the input / output lines can be suppressed, and the mutual coupling can be further suppressed because the ground conductor always exists between the input / output signal lines.

Next, an embodiment applied when connecting a plurality of high frequency circuits formed on a plurality of dielectric substrates having different relative dielectric constants will be described. FIG. 8 is an explanatory view showing this embodiment, in which 40 is one dielectric substrate and 41 is the other dielectric substrate. On one of the dielectric substrates 40, a signal line 42 is formed which is converted from the middle of the microstrip line into the transmission line according to the present invention. An upper ground conductor 43 is connected to the lower ground conductor by a through hole 44.

On the upper surface of the other dielectric substrate 41, a signal line 45 having a constant width and extending in the lateral direction is formed in the center, and the signal line 45 is formed by a microstrip line. The dielectric substrate 40 has a connection surface D
Is connected to the other dielectric substrate 41, and the signal line 42 is formed in a taper shape by gradually narrowing the line width so as to be equal to the width of the signal line 45 on the connection surface D. At the same time, the gap distance 46 from the upper ground conductor 43 is tapered so that the characteristic impedance of the signal line 42 becomes constant.

This eliminates the discontinuity in the line width when a high-frequency signal is transmitted from the signal line 42 formed on one dielectric substrate 40 to the signal line 45 formed on the other dielectric substrate 41. It is possible to eliminate the characteristic deterioration due to the discontinuity of the line width. This is exactly the same even when a plurality of high-frequency planar circuits configured on the same type of dielectric substrate having different thicknesses are connected.

Although the present invention has been described above, the present invention is not limited to the above embodiment, and for example, three or more dielectric substrates are connected on the same plane and configured on those substrates.
Of course, it can be applied to the case of connecting the above high frequency circuit. As described above, the present invention can be variously modified without departing from the spirit thereof.

[0034]

As described above, according to the present invention,
The width of the signal line in the high-frequency transmission line having the structure of the coplanar waveguide is continuously changed, and the gap between the signal line and the ground conductor is adjusted so that the characteristic impedance of the signal line becomes constant according to the change. Since the setting is made, it is possible to provide a high-frequency transmission line in which adjacent signal lines are less likely to influence each other when a high-frequency signal or the like is transmitted through the plurality of signal lines. Further, by continuously changing the gap interval with respect to the change of the width of the signal line in a linear manner to make the characteristic impedance of the signal line approximately constant, it is possible to easily process the end face portion of the ground conductor. It is possible to simplify the production of a kind of high-frequency transmission line.

When the semiconductor integrated circuit is mounted on a dielectric substrate having a low dielectric constant, adjacent transmission is performed even when the width of the signal line connected to each port becomes equal to or larger than the size of the semiconductor integrated circuit. It is possible to prevent the lines from affecting each other and degrading the isolation of the semiconductor integrated circuit.
Therefore, it is possible to provide an integrated circuit device capable of sufficiently exhibiting the original characteristics of the semiconductor integrated circuit. As a result, with the recent trend toward portability and cost reduction of communication devices, broadcasting devices, etc., it is possible to obtain the effect of being able to contribute to the demand for further size reduction.

Further, when a plurality of dielectric substrates having different relative permittivities or thicknesses are connected on the same plane, reflection loss due to discontinuity at the connecting surfaces is suppressed and the dielectric substrates are formed on those dielectric substrates. It is possible to provide a method of connecting high-frequency flat circuits, which can efficiently connect the high-frequency flat circuits to each other.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a high frequency transmission line according to the present invention.

FIG. 2 is a perspective view showing a main part of the structure of a coplanar waveguide.

3 is a graph showing the relationship between the signal line width W / gap width G and the reflection loss (dB) in the transmission line shown in FIG.

FIG. 4 is a graph showing the relationship between the signal line width W and the gap width G / signal line width W.

FIG. 5 is a graph showing a relationship between frequency (GHz) and reflection loss (dB).

FIG. 6 is a perspective view showing another embodiment of the high-frequency transmission line according to the present invention.

FIG. 7 is a plan view showing an embodiment in which the high-frequency transmission line according to the present invention is applied to mounting a high-frequency semiconductor integrated circuit.

FIG. 8 is a plan view showing an embodiment applied to the case of connecting a plurality of high-frequency flat circuits formed on dielectric substrates having different relative dielectric constants.

FIG. 9 is a plan view showing an example of a conventional high-frequency transmission line.

FIG. 10 is a plan view showing an example applied to the case of connecting a plurality of high-frequency planar circuits configured on conventional dielectric substrates having different relative dielectric constants.

[Explanation of symbols]

 15 strip line region 16 constant characteristic line region 17, 28, 30, 40, 41 Dielectric substrate 18, 19, 24, 32, 43 Upper ground conductor 20, 26, 34, 35, 36, 42, 45 Signal line 21, 25 Lower Grounding Conductor 22, 38, 44 Through Hole 23, 27, 39, 46 Gap Interval 31 High Frequency Semiconductor Integrated Circuit 37 Bond Wire

Claims (4)

[Claims] 1. A structure having a coplanar waveguide, in which the width of the signal line is continuously changed, and the characteristic impedance of the signal line is kept constant in accordance with the change, the signal line and the ground conductor. A high-frequency transmission line characterized in that a gap interval between them is set. 2. The gap spacing with respect to the change in the width of the signal line is continuously changed linearly with respect to the change in the width of the signal line so that the characteristic impedance of the signal line is approximately constant. The high frequency transmission line according to claim 1, wherein 3. A high-frequency semiconductor integrated circuit is mounted on a dielectric substrate having a high-frequency transmission line having a coplanar waveguide structure, and the width of an input / output signal line to / from this high-frequency semiconductor integrated circuit is continuously changed. The integrated circuit device is characterized in that the gap distance between the signal line and the ground conductor is set so that the characteristic impedance of the signal line becomes constant according to the change. 4. A signal line of a high frequency planar circuit having a structure of a coplanar waveguide formed on a plurality of dielectric substrates having different relative dielectric constants or different thicknesses connected on the same plane. Of the high-frequency plane circuit, characterized in that the gap distance between the signal line and the ground conductor is set so that the characteristic impedance of the signal line becomes constant according to the change. How to connect.