JPH07235846A - Microwave amplifier - Google Patents

Abstract

PURPOSE:To provide the microwave amplifier isolating an input and an output of a microwave active element without use of a special mechanism component. CONSTITUTION:An HEMT(high electron mobility transistor) 31 is mounted on a Teflon board 30 and source leads 32,33 are led from both sides of the board. A cover 20 is located on the Teflon board 30. A notch 20-2 formed on a wall 20-4 is placed so as to bridge over the HEMT 31 main body, and steps 20-1,20-3 formed on the wall 20-4 are placed corresponding to the source leads 32,33 of the HEMT 31 respectively. When the cover 20 is fitted to the main body case, the source leads 32,33 connect to ground via the steps 20-1,20-3 formed on the wall 20-4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave amplifier used in microwave equipment, and is particularly suitable for application to satellite broadcasting BS equipment and CS equipment.

[0002]

The device for constructing a low-noise amplifier of the Prior Art Microwave, G _{a A s} FET (gallium arsenide field effect transistor) or HEMT (High Elec
Microwave active devices such as tronMobility Transistors are commonly used. The HEMT is a semiconductor device in which high-mobility electrons accumulated on the heterojunction surface of a compound semiconductor are used as carriers, and is a transistor suitable for high-frequency amplification and high-speed operation. These microwave active elements are surface-mounted on the surface of an insulating substrate on which a circuit pattern is formed, and this insulating substrate is generally housed in a metal case.

In such a microwave active device, when the source electrode is used as the ground electrode, the gate electrode is used as the signal input electrode, and the drain electrode is used as the signal output electrode, spatial coupling between the input and output, Due to the relative phase relationship between the input signal supplied to the gate electrode and the output signal output from the drain electrode, abnormal oscillation or unstable amplification operation may be performed. In order to prevent such an operation, it has been conventionally practiced to use a metal separator, and the preventing means described in Japanese Patent Laid-Open No. 5-121975 is shown in FIG. 7 to FIG. A conventional example will be described with reference to FIG.

In FIG. 7, a circuit pattern is formed on the dielectric substrate 100, and H is formed on this circuit pattern.
The EMT 102 is mounted. And this HEMT
Separator 1 provided with a notch so as to straddle 102
01 is arranged along the grounded source electrode of the HEMT 102. Further, in another conventional example shown in FIG. 8, a separator 101 provided so as to straddle the HEMT 102 is soldered to a source electrode of the HEMT 102. In the means shown in FIG. 7, it is necessary to directly contact the separator 101 with the source electrode 103 of the HEMT 102 in order to enhance the oscillation prevention effect.
Due to the dimensional difference when mounting T102, it was difficult to make contact, and there was a drawback that the effect of preventing oscillation was low. Further, in order to obtain reliable grounding with the separator 101, it is necessary to press the separator 101 against the substrate 100, but there is a fear that the HEMT 102 may be broken due to the stress at the time of pressing. In addition, the means shown in FIG. 8 has a drawback that it is difficult to solder a large volume separator 101 and the HEMT 102 cannot be easily replaced.

Therefore, FIG. 9 shows still another conventional example in which these drawbacks are eliminated. In this conventional example, as shown in the top view of FIG. 1A, the gate electrode 106 and the drain electrode 107 of the HEMT 102 are connected to the circuit pattern 105 formed on the dielectric substrate 100 and are grounded. In the source electrode 103, the separator 10
The lower part of the metal fitting 108 sandwiched by 1 contacts. This metal fitting 108 is used for the separator 1 as shown in FIG.
A sandwiching piece 109 in which 01 is sandwiched is formed on the upper side, and a leg piece 110 which is in contact with the source electrode 103 and has elasticity is formed on the lower side. That is, the metal fitting 108
When the leg piece 110 is sandwiched between the separators 101 and comes into contact with the source electrode as shown in FIG. 2B, the leg piece 110 has elasticity, so that the HEMT 102 is surely grounded without being damaged. Can be obtained. Therefore, abnormal oscillation and unstable operation can be prevented. Further, since the leg piece 110 is only in contact with the electrode of the HEMT 102, the HEMT 102 can be easily replaced.

[0006]

However, in the conventional oscillation preventing means of the microwave amplifier, a special mechanical component such as a separator or a metal fitting is used to break the spatial coupling of the input and output. Therefore, there is a problem that the cost increases. Further, in the oscillation preventing means shown in FIG. 9, since the elasticity of the metal fitting is used, there is a problem that the durability is poor. Therefore, an object of the present invention is to provide a microwave amplifier in which input / output of a microwave active element is isolated without using a special mechanical component.

[0007]

In order to achieve the above object, a microwave amplifier of the present invention comprises a circuit pattern formed on an insulating substrate, a microwave active element mounted on the circuit pattern, In a microwave amplifier including a conductive main body case in which the insulating substrate is housed, and a conductive lid part fitted in the main body case, a wall portion forming a shield room is projected inside the lid portion. In addition, a notch portion and step portions are formed on both sides of the notch portion in the wall portion, and when the lid portion is fitted to the main body case, the step portion is the insulating substrate. The microwave active element mounted on the upper surface of the microwave active element is contacted so as to be pressed so that the input and output of the microwave active element are separated by the step and the notch. is there. Further, the microwave amplifier of the present invention is such that the insulating substrate is an insulating substrate having elasticity.

[0008]

According to the present invention, since no special mechanical component is used for isolation of the input / output of the microwave active element, the cost increase can be suppressed. Further, according to the present invention, the insulating substrate is a substrate having elasticity, so that it is possible to prevent the microwave active element from being broken and to improve the durability.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A converter including a microwave amplifier of the present invention is shown as an example in FIG. 1, and the present invention will be described with reference to this drawing. The converter 1 shown in this figure is used as a BS broadcast converter or a CS broadcast converter, and shows a state in which the conductive lid 20 is removed from the conductive main body case 10. As shown in this figure, a Teflon substrate 30 having a circuit pattern formed therein is housed in the main body case 10.
HEMTs 11 and 12 are mounted on 0. 4
0 is a frequency-converted BS-IF signal or CS-
This is a terminal for outputting an IF signal.

Further, as shown in the figure, concave portions are formed inside the lid portion 20 which is fitted into the main body case 10 to form a shield case, and which forms a plurality of shield rooms 21, 22, and 23. This shield room is formed to isolate the spatial coupling of input and output, and although it is not clear in this figure, HEM
The input and output of T11 and T12 are isolated by the wall portion forming the shield room. However, this isolation is performed in a state where the lid portion 20 is fitted to the main body case 10.

Therefore, a part of this wall portion is enlarged and shown in FIG. In this drawing, the HEMT is shown by the wall portion 20-4.
It shows the case of performing input / output isolation of.
The wall portion 20-4 has a cutout portion 20-2 and a step portion 20.
-1 and the step portion 20-3 are provided, the notch portion 20-2 is for allowing the wall portion 20-4 to straddle the HEMT main body, and the step portion 20-1 and the step portion 20-3 are provided. Reference numeral 20-3 is for sandwiching the source lead, which is the ground electrode of the HEMT, with the substrate 30. Such a wall portion 20-4 is formed on the lid portion 20 according to a circuit, and the shield rooms 21, 22, and 23 are provided in the wall portion 20.
It is formed by surrounding a predetermined space with -4, 20-5, 20-6 and the like.

Next, FIG. 3 shows a state in which the input / output of the HEMT is isolated by using the wall portion 20-4 shown in FIG. 2, and the lid portion 20 provided with the wall portion 20-4 is FIG. 4 shows a state immediately before being fitted into the main body case 10. However, the main body case 10 is omitted in these drawings. First, in FIG. 4, H is on the Teflon substrate 30.
The EMT 31 is mounted, and the source leads 32 and 33 are drawn out from both sides thereof. Further, the drain lead 34 (or gate lead) is drawn out so as to be orthogonal to the source lead. The lead out form of these leads is as shown in FIG. 9 (a).
The lid 20 is located on the Teflon substrate 30, and the notch 20- formed in the wall 20-4 of the lid 20.
2 is positioned so as to straddle the HEMT 31 main body, and a step portion 20- formed on the wall portion 20-4.
1 and the step portion 20-3 correspond to the source lead 3 of the HEMT 31.
2 and the source lead 33 are respectively positioned.

Then, the lid 20 is lowered and the main body case 1
When it is fitted to 0, the state shown in FIG. 3 is obtained. That is, the source leads 32 and 33 have the step portions 20-1 and 20-2 formed on the Teflon substrate 30 and the wall portion 20-4.
It becomes to be pinched by 0-3. At this time, the step portions 20-1 and 20-3 press the source leads 32 and 33, so that reliable grounding can be performed via the wall portion 20-4. When the step portions 20-1 and 20-3 press the source leads 32 and 33 of the HEMT 31, the HEMT 31 is more reliably grounded because the substrate 30 is made of Teflon having elasticity.

Next, FIG. 6 shows the frequency characteristic and the return loss characteristic of the microwave amplifier according to the present invention. For comparison, the frequency characteristic and the return loss characteristic of the microwave amplifier shown in FIG. 7 are shown. 5 and will be described by comparing these characteristics. First, in FIG. 5, the gain of the microwave amplifier is a high gain of about 50 dB in the use band of the frequency range between the inverted triangles indicated by "1" and "2", and the return loss is the use of the same frequency range. In the band, it is -10 dB to -15 dB, which is a sufficiently satisfactory characteristic. However, the return loss exceeds 0 dB in the part shown as A surrounded by the broken line above the used band. As described above, it has been confirmed that when the return loss exceeds 0 dB, phenomena such as abnormal oscillation occur in the exceeded frequency range.
It can be sufficiently predicted that the microwave amplifier having the characteristics shown in (1) causes abnormal oscillation. That is, it is understood that the oscillation preventing means in the microwave amplifier shown in FIG.

On the other hand, referring to the frequency characteristic and the return loss characteristic of the microwave amplifier of the present invention provided with the oscillation preventing means, the gain is the frequency between the inverted triangles indicated by "1" and "2". Approximately 50 dB in the band used
The return loss is set to -10 dB to -15 dB in the use band of the same frequency range. Furthermore, the return loss is 0d even in the frequency range shown as B surrounded by the broken line above the frequency band used.
Since it is B or less, it is understood that the microwave amplifier of the present invention is a microwave amplifier capable of performing stable amplification operation without causing abnormal oscillation at any frequency. The center frequency of the characteristics shown in FIGS. 5 and 6 is, for example, 12 GHz.

In the above description, the Teflon substrate having elasticity is used as the insulating substrate, but the substrate is not limited to the Teflon substrate and any substrate having elasticity and good high frequency characteristics can be used. May be used. In the above description has been described as using a HEMT as a microwave device, not limited thereto, G _a A _s that may be used microwave active element such as an FET it is a matter of course.

[0017]

As described above, according to the present invention, the input / output isolation of the microwave active element can be surely performed by utilizing the wall portion formed in the lid portion which constitutes the shield case, and for that reason. Since no special mechanical parts are required, the cost increase can be suppressed. Furthermore, according to the present invention, since the insulating substrate is a substrate having elasticity, the microwave active element can be prevented from being broken and the durability can be improved.

[Brief description of drawings]

FIG. 1 is an overall view of a converter including a microwave amplifier according to the present invention with a lid removed.

FIG. 2 is an enlarged view showing a part of a lid portion.

FIG. 3 is a diagram showing a coupling relationship between a wall portion formed on a lid portion and an insulating substrate.

FIG. 4 is a diagram showing a positional relationship between a wall portion formed on a lid portion and an insulating substrate.

FIG. 5 is a diagram showing characteristics of a conventional microwave amplifier.

FIG. 6 is a diagram showing characteristics of the microwave amplifier of the present invention.

FIG. 7 is a diagram showing a configuration of a conventional microwave amplifier.

FIG. 8 is a diagram showing another configuration of a conventional microwave amplifier.

FIG. 9 is a diagram showing still another configuration of a conventional microwave amplifier.

[Explanation of symbols]

 1 Converter 10 Body case 11,12,31,102 HEMT 20 Lid part 20-1,20-3 Step part 20-2 Notch part 20-4,20-5,20-6 Wall part 21,22,23 Shield Room 30 Teflon substrate 32, 33 Source lead 34 Drain lead 40 Terminal 100 Dielectric substrate 101 Separator 103 Source electrode 104 Soldering 105 Circuit pattern 106 Gate electrode 107 Drain electrode 108 Metal fitting 109 Clamp piece 110 Leg piece

Claims (2)

[Claims] 1. A circuit pattern formed on an insulating substrate,
A microwave active element mounted on this circuit pattern, and a conductive body case in which the insulating substrate is housed,
In a microwave amplifier including a conductive lid fitted to the body case, a wall forming a shield room is projected inside the lid, and a notch is formed in the wall. A step portion is formed on both sides of the cutout portion, and when the lid portion is fitted to the main body case, the step portion is connected to the ground electrode of the microwave active element mounted on the insulating substrate. The microwave amplifier characterized in that the input and output of the microwave active element are separated by the step portion and the cutout portion while being pressed and brought into contact with each other. 2. The microwave amplifier according to claim 1, wherein the insulating substrate is an insulating substrate having elasticity.