JPS635282Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is concerned with improving the performance of a single-throw bipolar semiconductor switch that controls microwaves using an FET constructed on a semiconductor substrate.

FIG. 1 shows a perspective view of an example of the configuration of a conventional single-throw bipolar semiconductor switch.

In the figure, 1 is a semiconductor substrate, 2 is a ground conductor, 3 is a main line consisting of a microstrip line configured together with the ground conductor 2, 4a is a first sub-line also made of a microstrip line, and 4b is also a The second sub line is a microstrip line, 5 is an FET,
6 is the drain electrode of FET5, 7a is the same FET
5 is the first source electrode of FET 5, 7b is the second source electrode of FET 5, and 8a is the first source electrode of FET 5.
8b is the second gate electrode of the FET 5, and 9a and 9b are bias circuits consisting of microstrip lines for applying bias voltage to the first gate electrode 8a and the second gate electrode 8b, respectively. It is.

A conventional single-throw double-pole semiconductor switch has three main lines.
and the first and second sub-lines 4a, 4b are arranged at right angles, the drain electrode 6 of the FET 5 is connected to the main line 3, and the first source electrode 7a and second source electrode 7b are connected to the first line 3, respectively. sub-line 4a and second
The portions between the drain electrode 6 and the first source electrode 7a and between the drain electrode 6 and the second source electrode 7b of the FET 5 form an interdigital structure, and are bent into this interdigital structure. First and second gate electrodes 8a and 8b of the structure are formed.

In this case, the bottom of the recess of the first source electrode 7a in the FET 5 and the second source electrode 7b
It was formed in a parallel relationship with the bottom of the recess.

Figure 2 is a diagram used to explain the characteristics of a typical FET, and shows the voltage and current characteristics between the source and drain electrodes when the bias voltage of the gate electrode is changed. In the figure, numerals 10 and 11 are characteristic curves when the bias voltage of the gate electrode is zero and in a pinch-off state, respectively.

For convenience of explanation, the voltage between the source electrode and the drain electrode is assumed to be V _DS and the current is assumed to be I _DS here.

At this time, the resistance R _DS between the source electrode and the drain electrode is expressed as R _DS =V _DS /I _DS .

Figures 3a and 3b are diagrams used to explain a 90-degree corner section consisting of a general microstrip line.
b is the unaligned corner and b is the aligned corner. In the figure, 12a and 12b indicate internal conductor patterns of mismatched corners and matched corners, respectively, and 13 indicates a cut portion.

A conventional single-throw double-pole semiconductor switch will be described below with reference to these figures.

Now, consider the case where microwaves are applied to the main line 3. A bias circuit 9a is connected to the first gate electrode 8a.
Applying zero voltage through the second gate electrode 8b
When a pinch-off voltage is applied to the first source electrode 7a and the drain electrode 6 through the bias circuit 9b, as can be seen from FIG. The resistance between them shows a large value. Therefore, the microwave from the main line 3 is transmitted to the first sub-line 4a.

On the other hand, if the bias voltage conditions of the first gate electrode 8a and the second gate electrode 8b are reversed, the microwave from the main line 3 is similarly transmitted to the second sub-line 4b.

In this way, the first and second gate electrodes 8a, 8
By changing the bias voltage to b, a single-throw double-pole semiconductor switch can be realized.

However, if we consider as an example the state in which microwaves are transmitted from the main line 3 to the first sub-line 4a, the drain electrode 6 on the second sub-line 4b side will affect the matching of the single-throw bipolar semiconductor switch. Deterioration is seen in the characteristics.

This is because the convex portions of the drain electrode 6 are generally arranged in a large number, and the FET 5 section is
This is because it functions in the same way as the misaligned corner of .

In this way, in a single-throw double-pole semiconductor switch,
Due to the shape of FET5, matching characteristics deteriorated, which became a problem.

This invention solves the above problem by using FET
The purpose of this is to change the loading shape of the FET 5 and eliminate the deterioration in matching characteristics of the single-throw bipolar semiconductor switch due to the influence of the shape of the FET 5.

FIG. 4 is a plan view showing the structure of a single-throw bipolar semiconductor switch according to an embodiment of the invention.

The single-throw bipolar semiconductor switch based on this idea is
Main line 3, first sub line 4a, second sub line 4b
The tapered part of the main line 3 and the one-side tapered part of the first and second sub-lines 4a and 4b are made to be tapered so that the tips of the main line 3 and the first and second sub-lines 4 are isosceles.
a and 4b are arranged adjacent to each other so as to be perpendicular to each other, and these adjacent parts have an interdigital configuration.

In addition, the interdigital part of the main line 3 is connected to FET5.
The drain electrode 6 of the FET 5 is the interdigital part of the first sub-line 4a, and the first source electrode 7 of the FET 5 is the interdigital part of the first sub-line 4a.
a, and the interdigital part of the second sub-line 4b is used as the second source electrode 7b of the FET 5.

Further, a first gate electrode 8a is formed in a bent structure between the drain electrode 6 and the first source electrode 7a of the FET 5, and a second gate electrode 8a is formed in a bent structure between the drain electrode 6 and the second source electrode 7b of the FET 5.
A gate electrode 8b is formed.

The single-throw bipolar semiconductor switch according to this invention will be explained below with reference to these figures.

The basic operation of the single-throw bipolar semiconductor switch according to this invention (first and second gate electrodes 8a,
8b) is the same as that of a conventional single-throw double-pole semiconductor switch, so a description thereof will be omitted.

In the single-throw double-pole semiconductor switch according to this invention, if we take as an example a state in which microwaves are transmitted from the main line 3 to the first sub-line 4a, we can assume that in the second sub-line 4b.
The tapered portion forming a part of the FET 5 performs the same function as the cut surface 13 in FIG. 3b, and the matching characteristics are improved.

This includes the main line 3, the first sub line 4a and the second
The tip of the sub-line 4b is tapered to be isosceles,
The tapered part of the main line 3 and the one-sided tapered part of the first and second sub-lines are arranged adjacent to each other, and these adjacent parts
Since FET5 is formed, the microwave is the first
Alternatively, in the state where the signal is transmitted to the second sub-lines 4a and 4b, the matching corner in FIG. 3b functions very closely.

As described above, in the single-throw bipolar semiconductor switch according to this invention, by changing the mounting shape of the FET 5 installed at the intersection of the main line 3 and the first and second sub-lines 4a and 4b and the shape of the intersection, Improved matching characteristics.

Although the above description has been made regarding a single-throw bipolar semiconductor switch, this invention is not limited to this, and may be applied to a switched line type semiconductor phase shifter.

As described above, in the single-throw bipolar semiconductor switch according to this invention, by changing the loading shape of the FET, the FET loading portion can be matched, which is effective in improving the characteristics.

[Brief explanation of drawings]

Figure 1 is a perspective view showing the configuration of a conventional single-throw bipolar semiconductor switch, Figure 2 is a diagram showing the static characteristics of FET used to explain general FETs, Figure 3 a, b
Figure 4 is a diagram used to explain a 90-degree corner made of a general microstrip line. 1 is a plan view showing the configuration of a single-throw bipolar semiconductor switch according to an embodiment; FIG. In the figure, 1 is a semiconductor substrate, 2 is a ground conductor, 3 is a main line, 4a and 4b are first and second sub-lines, and 5 is a ground conductor.
FET, 6 is a drain electrode, 7a, 7b are first and second source electrodes, 8a, 8b are first and second
gate electrodes, 9a and 9b are bias circuits, 10
is a characteristic curve, 11 is a characteristic curve, 12a and 12b are
The internal conductor pattern at the 90 degree corner, 13 is the cut surface. It should be noted that the same or corresponding parts in the figures are indicated by the same reference numerals.

Claims (1)

[Scope of utility model registration request] In a single-throw bipolar semiconductor switch formed by connecting an FET formed on a semiconductor substrate and a microstrip line formed on the semiconductor substrate, a main line formed of the microstrip line, a first sub-line, and The tip of the second sub-line is formed into an isosceles taper, and the tapered part of the main line and the first
and a second sub-line with one-sided tapered portions arranged adjacent to each other so that the main line and the first and second sub-lines are perpendicular to each other, and the main line and the first and second sub-lines The part adjacent to the sub line has an interdigital configuration, the main line of the interdigital part is used as the drain electrode of the FET, and the first and second sub lines of the interdigital part are used as the first and second lines of the FET, respectively. A first gate electrode is formed with a bent structure between the drain electrode of the FET and the first source electrode, and a second gate electrode is formed between the drain electrode of the FET and the second source electrode. 1. A single-throw bipolar semiconductor switch, characterized in that the gate electrode of the upstream FET is formed in a bent structure, and that the first and second gate electrodes of the upstream FET are each provided with means for applying a bias voltage.