JP2000068715A - Transforming unit of microstrip line and coplanar line and package substrate using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the transforming unit of a microstrip line and a coplanar wave guide, which is difficult to generate mismatching. SOLUTION: A first connecting electrode 3 is formed on one main surface 2a of a substrate 2, and a first distribution line 4 opposed to the electrode 3, a second distribution line 5 obtained by connecting the end parts of the first line 4 and the second line 5 with each other and a second ground electrode 7 adjacent to the side edge of the line second 5 are respectively formed on the other main surface 2b. At the connecting part of the first line 4 and the second line 5, a gap 6 between the side edge of the second line 5 and the first electrode 7 is formed by expanding in the state of a taper from the position of the second line 5 in the direction of the first line 4 and an electrode deleting part 12 expanding in the state of a taper from a position opposed to the first line 4 toward a position opposed to the second line 4 is provided at the first electrode 3. Thus, it is possible to prevent mismatching between the microstrip line consisting of the first distribution constant line and the coplanar wave guide consisting of the second distribution constant line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microstrip line and a coplanar line (coplanar waveguide).
The present invention relates to a converter of a microstrip line and a coplanar line used for a package substrate for an electronic device using high-frequency signals, and a package substrate using the same.

[0002]

2. Description of the Related Art With the recent miniaturization of communication devices and the use of higher frequencies, mismatch between a conversion section of a microstrip line and a coplanar line formed on a package substrate for an electronic device has caused the high frequency characteristics of the electronic device to become poor. Is likely to deteriorate, and it is necessary to improve the mismatch of the conversion unit.

FIG. 5 shows a perspective view of a conventional converter of a microstrip line and a coplanar line. FIG. 6A is a plan view of the microstrip line and coplanar line converter shown in FIG. 5, and FIG. 6B is a bottom view thereof. In the converter 1 of the microstrip line and the coplanar line shown in FIGS.
A first ground electrode 3 is formed on one main surface 2a, and a first distributed constant line 4 is formed on the other main surface 2b so as to face the first ground electrode 3. Also, the other main surface 2 of the substrate 2
b, a second distributed constant line 5 is formed by connecting the first distributed constant line 4 and the ends thereof, and the second distributed constant line 5 is formed adjacent to the side edge of the second distributed constant line 5 via the gap 6. Two ground electrodes 7 are formed. Further, no capacitance is formed between the second distributed constant line 5 and the first ground electrode 3 at a position on the one main surface 2a of the substrate 2 facing the second distributed constant line 5 and around it. As described above, the electrode removing portion 8 of the first ground electrode 3 is formed. Further, the side edge of the first distributed constant line 4 and the second ground electrode 7 are formed to be sufficiently larger than the gap 6 so that a capacitance is not formed between them as much as possible.

[0004] With this configuration, the substrate 2
Is divided into two regions, a region s1 where the first distributed constant line 4 is formed and a region s2 where the second distributed constant line 5 is formed. Here, in the region s1, the first distributed constant line 4 operates as a microstrip line together with the first ground electrode 3, and in the region s2, the second distributed constant line 5 operates as a coplanar line together with the second ground electrode 7. I do. Then, by making the characteristic impedances of the first distributed constant line 4 and the second distributed constant line 5 coincide, it functions as a converter between the microstrip line and the coplanar line.

[0005]

However, in the converter 1 of the microstrip line and the coplanar line shown in FIG. 5 and FIG. A local stray capacitance is generated at the connection between the two distributed constant lines 5. That is, in the vicinity of the connection portion,
A stray capacitance is formed between the first distributed constant line 4 and the second ground electrode 7, and a stray capacitance is also formed between the second distributed constant line 5 and the first ground electrode 3. You. And
There is a problem that these stray capacitances cause a mismatch between the converters of the microstrip line and the coplanar line.

SUMMARY OF THE INVENTION An object of the present invention is to provide a converter of a microstrip line and a coplanar line, which hardly causes a mismatch, and a package substrate using the same.

[0007]

In order to achieve the above object, a converter of a microstrip line and a coplanar line according to the present invention has a first ground electrode formed on one main surface of a substrate, and a second ground electrode formed on the other main surface of the substrate. A first distributed constant line facing the first ground electrode on the main surface, a second distributed constant line formed by connecting the first distributed constant line and an end to each other, A second ground electrode is formed adjacent to a side edge of the distributed constant line, and the first distributed constant line and the second ground electrode are formed.
In the connection part of the distributed constant line, the gap between the side edge of the second distributed constant line and the second ground electrode is
The first distributed constant line is formed so as to expand in a tapered shape from the position of the second distributed constant line toward the first distributed constant line, and the first ground electrode is provided with a position facing the first distributed constant line. And an electrode removing portion that extends in a tapered shape from a position facing the second distributed constant line.

[0008] A package substrate according to the present invention is characterized in that it is constructed using the above-mentioned converter for a microstrip line and a coplanar line.

With this configuration, according to the microstrip line and coplanar line converter of the present invention, the mismatch of the converter can be reduced.

According to the package substrate of the present invention,
It is possible to prevent high-frequency characteristics from deteriorating, and thereby prevent high-frequency characteristics from deteriorating in an electronic device using the same.

[0011]

FIG. 1 is a perspective view showing an embodiment of a converter for a microstrip line and a coplanar line according to the present invention. FIG. 2A is a plan view of the microstrip line and coplanar line converter shown in FIG. 1, and FIG. 2B is a bottom view thereof. 1 and 2
In FIG. 6, the same or equivalent parts as those in FIGS. 5 and 6 are denoted by the same reference numerals, and description thereof will be omitted.

The converter 10 of the microstrip line and the coplanar line shown in FIG. 1 and FIG. 2 is connected to the first distributed constant line 4 and the second distributed constant line 5 at the second distributed constant line 5. Gap 11 between the side edge of the second distributed electrode line 5 and the second ground electrode 7
Of the distributed constant line 4 in a tapered shape. Similarly, the first distributed constant line 4
In the connection portion between the first and second distributed constant lines 5, the first ground electrode 3 is tapered from a position facing the first distributed constant line 4 toward a position facing the second distributed constant line 5. A widening electrode removing section 12 is provided. Here, the side edge of the second distributed constant line 5 and the second ground electrode 7
The gap 11 between the first ground electrode 3 and the portion where the first ground electrode 3 is provided with the electrode removing portion 12 that extends in a tapered manner is defined as a region s3.

By providing the region s3 in this manner, the capacitance formed between the first distributed constant line 4 and the second distributed constant line 5 and the first ground electrode 3 in the region s3 is , Gradually decreases from the region s1 toward the region s2. Conversely, the capacitance formed between the first distributed constant line 4 and the second distributed constant line 5 and the second ground electrode 7 gradually increases from the region s3 toward the region s2. I do. As a result, in the region s3, the first distributed constant line 4 and the second distributed constant line 5
Has both the characteristics of the microstrip line and the characteristics of the coplanar line, and the characteristics change continuously from one to the other.

For this reason, there is almost no locally large stray capacitance from the position of the first distributed constant line 4 toward the second distributed constant line 5, and the first distributed constant line 4 and the second distributed constant line Does not change substantially between the distributed constant line 5 and the first ground electrode 3 and the second ground electrode 7. As a result, the mismatch between the first distributed constant line 4 and the second distributed constant line 5 can be almost eliminated, and a converter of a microstrip line and a coplanar line with small mismatch can be formed. it can.

FIG. 3 shows the return loss of the microstrip line and coplanar line converter 10 of the present invention. FIG.
, X1 indicated by a broken line indicates the reflection loss of the converter 1 of the conventional microstrip line and coplanar line shown in FIG. 5, and x2 indicated by a solid line indicates the microstrip line and the coplanar line of the present invention shown in FIG. 10 shows the return loss of 10 transducers. Here, a larger reflection loss (the lower one in FIG. 3) means that the mismatch is smaller.

From FIG. 3, it can be seen that the microstrip line and coplanar line converter 10 of the present invention can obtain a larger reflection loss and reduce the mismatch than the conventional microstrip line and coplanar line converter 1. I understand.

Incidentally, the tapered shape of the electrode removing portion 12 formed on the first ground electrode 3 and the second distributed constant line 5
The shape of the portion where the gap 11 between the side edge of the second and the second ground electrode 7 is tapered wide is not limited to a linearly changing shape as shown in FIGS. It may be in the shape of a small step or a fine step, and has the same effect.

1 and 2, the tapered portion of the gap 11 between the side edge of the second distributed constant line 5 and the second ground electrode 7 in the region s3, The lengths of the tapered portion of the electrode removing portion 12 of the first ground electrode 3 in the longitudinal direction of the first and second distributed constant lines 5 and 7 are the same, but must always be the same. Instead, any one of the tapered portions may be long, and the same effect can be obtained.

In the embodiments shown in FIGS. 1 and 2, the widths of the first distributed constant line 3 and the second distributed constant line 5 are assumed to be equal to each other. At the same time, a portion in which both widths change in a tapered shape may be provided in the region s3. With this configuration, the first distributed constant line and the second
In the case where the width of the distributed constant line is different, a converter of a microstrip line and a coplanar line with a small mismatch can be similarly formed.

FIG. 4 shows an embodiment of the package substrate of the present invention. Here, FIG. 4A is a plan view, and FIG.
Shows a bottom view.

In FIG. 4, a second ground electrode 22 is provided on one main surface 21a of a substrate 21 forming a package substrate 20.
However, a first ground electrode 23 is formed on the other main surface 21b. A first distributed constant line 23 and a second distributed constant line 25 whose ends are connected to each other are formed at an end of one main surface 21a of the substrate 21. A via pad 26 is formed on the other main surface 21 b of the substrate 21. Then, one end of the second distributed constant line 25 and the via pad 26
Are connected by a via hole 27. The gap 28 between the side edge of the first distributed constant line 24 and the second distributed constant line 25 and the second ground electrode 22 is formed between the second distributed constant line 25 and the first distributed constant line 24. Is formed so as to expand in a tapered shape from the position of the second distributed constant line 25 toward the first distributed constant line 24. Similarly, at the connection between the second distributed constant line 25 and the first distributed constant line 24, the first grounded electrode 23 is provided with a second distributed constant from a position opposed to the first distributed constant line 24. An electrode removing portion 29 that expands in a tapered shape toward a position facing the line 25 and an electrode removing portion 30 that further surrounds the via pad 26 are formed. Here, the connecting portion between the first distributed constant line 24 and the second distributed constant line 25 has the same structure as the converter of the microstrip line and the coplanar line of the present invention shown in FIG.

The package substrate 20 thus configured
, An integrated circuit (not shown) or the like is mounted on the second ground electrode 23 on the other main surface 21b of the substrate 21, and the input / output bonding pads (not shown) and the via pads 26 are connected to the bonding wires (not shown). (Not shown) to form an electronic device. At this time, a high-frequency signal flows from the integrated circuit to the first distributed constant line 24 via the via pad 26, the via hole 27, and the second distributed constant line 25 in this order.

In the package substrate 20 configured as described above, since the mismatch between the first distributed constant line 24 and the second distributed constant line 25 is reduced, deterioration of the high frequency characteristics of the package substrate 20 is prevented. As a result, it is possible to prevent the high-frequency characteristics of the electronic device using the same from deteriorating.

[0024]

According to the microstrip line and coplanar line converter of the present invention, the first ground electrode is formed on one main surface of the substrate, and the other main surface is opposed to the first ground electrode. A first distributed constant line, a second distributed constant line formed by connecting the first distributed constant line and the ends thereof, and a second ground electrode formed close to a side edge of the second distributed constant line. Are formed, and at the connection portion between the first distributed constant line and the second distributed constant line, the side edge of the second distributed constant line and the second
A gap between the first distributed constant line and the second distributed constant line is formed in a tapered shape from the position of the second distributed constant line toward the first distributed constant line. The mismatch between the first distributed constant line and the second distributed constant line is provided by providing an electrode removing portion that extends in a tapered shape from the position facing the line to the position facing the second distributed constant line. Can be prevented.

According to the package substrate of the present invention,
By using the converter of the microstrip line and the coplanar line of the present invention, it is possible to prevent high-frequency characteristics from deteriorating, and thus prevent electronic devices using the same from deteriorating.

[Brief description of the drawings]

FIG. 1 is a perspective view of a microstrip line and coplanar line converter according to an embodiment of the present invention.

FIG. 2 is a plan view of the converter of the microstrip line and the coplanar line of FIG. 1;

FIG. 3 is a diagram showing the return loss of the converter of the microstrip line and the coplanar line of FIG. 1;

FIG. 4 is a sectional view showing an embodiment of the package substrate of the present invention.

FIG. 5 is a perspective view of a conventional converter of a microstrip line and a coplanar line.

FIG. 6 is a plan view of the converter of the microstrip line and the coplanar line of FIG. 5;

[Explanation of symbols]

2 Base 2a One main surface 2b Other main surface 3 First ground electrode 4 First distributed constant line 5 Second distributed constant line 7 Second ground electrode 8, 12 Electrode deleted part 10 ... Transformer between microstrip line and coplanar line 11 ... Gap 20 ... Package substrate

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tsutomu Takai 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Inside Murata Manufacturing Co., Ltd.

Claims (2)

[Claims] A first ground electrode formed on one main surface of the substrate; a first distributed constant line formed on the other main surface of the substrate so as to face the first ground electrode; A second distributed constant line formed by connecting the distributed constant lines and the ends thereof, and a second ground electrode formed near a side edge of the second distributed constant line, respectively, wherein the first distribution At a connection between the constant distributed line and the second distributed constant line, a gap between a side edge of the second distributed constant line and the second ground electrode is formed from the position of the second distributed constant line. The first distributed constant line is formed so as to expand in a tapered shape, and the first ground electrode is opposed to the second distributed constant line from a position opposed to the first distributed constant line. It is characterized by providing an electrode removal part that expands in a tapered shape toward the position Converter Lee cross trip line and the coplanar line. 2. A package substrate using the microstrip line and coplanar line converter according to claim 1.