JPH10284508A - Microwave switch element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microwave switch element having satisfactory switch characteristics in milliwave bands. SOLUTION: One end of gate finger electrode 13 at an FET is connected to one end of 1st gate power feeding line 14, a 1st resistor 15 having a high resistance value is connected to the other end of this 1st gate power feeding line 14, the other end of gate finger electrode 13 is connected to one end of 2nd gate power feeding line 17, and a 2nd resistor 18 having a high resistance value is connected to the other end of this 2nd gate power feeding line 17. The gate electrode 13, source electrode 12, drain electrode 11, two gate power feeding lines 14 and 17 and two resistors 15 and 18 are respectively constituted point-symmetric.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave switch device using a field effect transistor (hereinafter, referred to as FET).

[0002]

2. Description of the Related Art FIG. 3 is a schematic plan view showing a conventional microwave switch device using an FET.

A microwave signal supplied from a signal source (not shown) is input to a drain electrode 11 and
2 output. The gate finger electrode 13 is connected to a gate power supply line 24, and a resistor 25 for opening the gate electrode at a high frequency is connected to the other end of the gate power supply line 24, and a bias is supplied via the resistor 25. .
Here, since the microwave switch element using the FET is basically used as a passive element, it has bidirectional characteristics, that is, S11 = S22, S21 in the scattering matrix.
= S12 is necessary to obtain good characteristics as a switch element.

However, in the microwave switch element shown in FIG. 3, since the gate feed line 24 is provided only on the source electrode 12 side, the source electrode 12 and the gate feed line 24
At the intersection 16 of the MIM (Metal-Insul
ator-Metal) capacitors are formed. For this reason, the conditions of S11 = S22 and S21 = S12 are not satisfied, and symmetric characteristics cannot be obtained. In particular, when the switch element shown in FIG. 3 is used in the millimeter wave band, the influence of the MIM capacitor formed at the intersection 16 appears remarkably, causing deterioration of the switch characteristics.

[0005]

As described above, in the conventional microwave switch element, the MIM formed by the portion 16 where the source electrode 12 and the gate feed line 24 intersect is formed.
Due to the influence of the capacitor, bidirectionally symmetric characteristics as a switch cannot be obtained, which has led to deterioration of the switch characteristics particularly in the millimeter wave band.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a microwave switch element having good switching characteristics.

[0007]

According to the present invention, there is provided a microwave switching device using a field effect transistor having a gate finger electrode provided between a source electrode and a drain electrode. Even if the first gate power supply line connected to one end of the gate finger electrode and supplying power to the gate electrode, and the second gate power supply line connected to the other end of the gate finger electrode and supplying power to the gate electrode are replaced, the pattern and the characteristics are different. It is characterized in that they are configured to be equal.

In addition, the first resistance and the second resistance, which are sufficiently large with respect to the impedance of the field effect transistor,
It is characterized in that they are respectively connected to the first gate feed line and the second gate feed line.

[0009] Further, the resistance value of the first resistor is equal to the resistance value of the second resistor.

Also, one gate feed line and a source electrode,
The other gate feed line and the drain electrode cross each other via a dielectric.

A gate feed line and a source electrode;
The other gate feed line and the drain electrode intersect with each other via air.

In the microwave switch device having this configuration, by connecting the gate power supply lines to both ends of the gate finger electrode, the structure of the switch can be made completely symmetrical with respect to the source and the drain. Bidirectional symmetric characteristics can be obtained.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a schematic plan view showing the structure of the microwave switch element of the present invention.

In FIG. 1, a gate finger electrode is disposed point-symmetrically between two opposing source and drain electrodes, and two gate feeder lines and two resistors are provided at both ends of the gate finger electrode. Are arranged so as to be point symmetrical. A first gate power supply line connected to one end of the gate finger electrode and supplying power to the gate electrode, and a pattern formed by replacing the second gate power supply line connected to the other end of the gate finger electrode and supplying power to the gate electrode; The characteristics are configured to be equal.

In FIG. 1, one end of a gate finger electrode 13 is connected to one end of a first gate feed line 14, and the other end of the gate finger electrode 13 is connected to one end of a second gate feed line 17. A first resistor 15 having a sufficiently large resistance value with respect to the impedance of the FET is connected to the other end of each of the first gate power supply line 14 and the second gate power supply line 17.
And the second resistor 18 are connected to the gate finger electrode 13 at positions equidistant from each other. The gate feed line 14 and the source electrode 12 intersect at 16 via a dielectric, and the gate feed line 17 and the drain electrode 11 intersect at 19 via a dielectric.

FIG. 1 shows the structure of the gate finger electrode 1.
3, a completely symmetrical structure with respect to the drain electrode 11 and the source electrode 12, and if the drain electrode 11 is an input terminal and the source electrode 12 is an output terminal, the scattering matrix is S11 = S
22, the relationship of S21 = S12 can be obtained, and good bidirectional characteristics as a switch element can be obtained.

In the embodiment of the present invention described above,
Although the simplest field-effect transistor using two opposing comb-shaped source / drain electrodes has been described, the present invention is not limited to this, and the present invention uses more than two comb-teeth and the same number of source / drain electrodes. Can be applied even if

In the above embodiment, the case of one field effect transistor has been described. FIG. 2 is a schematic plan view showing the case of two field-effect transistors having a common drain.

In FIG. 2, a gate finger electrode is arranged point-symmetrically between two source electrodes and a drain electrode facing each other, and two gate power supply lines and two resistors are provided at both ends of the gate finger electrode. Are arranged in a point symmetrical manner, and two field effect transistors are arranged with a common drain.

In FIG. 2, a gate finger electrode 33,
One end of 43 is connected to one end of the first gate feed lines 34 and 44, and the other end of the gate finger electrodes 33 and 43 is connected to one end of second gate feed lines 37 and 47. Further, the first gate power supply lines 34 and 44 and the second gate power supply line 3
The first and second resistors 35 and 45 and the second resistors 38 and 48 having sufficiently large resistance values to the impedance of the FET are connected to the other ends of the gate finger electrodes 33 and 47, respectively.
3 are connected to positions at an equal distance from each other. Also,
The gate feed line 37 and the source electrode 32 intersect at 36 via a dielectric, and the gate feed line 34 and the drain electrode 3
1 intersects at 39 via the dielectric.

In the embodiment shown in FIG. 1, the gate power supply line 14 and the source electrode 12, and the gate power supply line 17 and the drain electrode 11 intersect via the dielectric. However, at the intersection of these two locations, the gate feed line and the source electrode, and the gate feed line and the drain electrode may intersect via air. That is, a so-called air bridge system may be used.

[0023]

As described above, according to the present invention, it is possible to provide a microwave switching device having good switching characteristics.

[Brief description of the drawings]

FIG. 1 is a schematic plan view illustrating the present invention.

FIG. 2 is a schematic plan view illustrating the present invention.

FIG. 3 is a schematic plan view illustrating a conventional example.

[Explanation of symbols]

11, 31 drain electrode 12, 32, 42 source electrode 13, 33, 43 gate finger electrode 14, 34, 44 first gate feed line 17, 37, 47 second gate feed line 15, 35 , 45: first resistor 18, 38, 48 ... second resistor 16, 36, 46 ... intersection of source electrode and gate finger electrode 19, 39, 49 ... intersection of drain electrode and gate finger electrode 24 ... Gate feed line 25 ... Resistance

Claims (5)

[Claims] 1. A microwave switch device using a field effect transistor having a gate finger electrode provided between a source electrode and a drain electrode, the first gate being connected to one end of the gate finger electrode and supplying power to the gate electrode. A microwave characterized in that even if a power supply line and a second gate power supply line connected to the other end of the gate finger electrode and supplying power to the gate electrode are replaced, patterns and characteristics are the same. Switch element. 2. The method according to claim 1, wherein a first resistor and a second resistor that are sufficiently large with respect to the impedance of the field effect transistor are connected to the first gate feed line and the second gate feed line, respectively. The microwave switch element according to claim 1, wherein 3. The microwave switch device according to claim 1, wherein the first resistor and the second resistor have the same resistance value. 4. The microwave switch device according to claim 1, wherein one gate power supply line and the source electrode cross each other, and another gate power supply line and the drain electrode cross each other via a dielectric. 5. The microwave switch device according to claim 1, wherein one gate power supply line and the source electrode cross each other, and another gate power supply line and the drain electrode cross each other via air.