JPS6148201A - Low noise amplifier - Google Patents

Abstract

PURPOSE:To simplify the structure and to improve the cooling efficiency by mounting an amplifier formed of MIC to a cut-off shape part of a waveguide to cool directly the said amplifier. CONSTITUTION:The middle part 11 of the waveguide 10 is narrowed for the height and lateral width to an input/output part at both ends as a taper and formed into the cut-off shape. The amplifier circuit 12 is mounted to the cut- off part 11. The amplifier circuit 12 is subjected to MIC by mounting an FET chip 12a on a carrier 12b. Further, the amplifier circuit 12 is cooled directly by an electronic cooling module 15. Since the amplifier circuit is mounted to the insid of the waveguide in this way to simplify the structure. Since the amplifier circuit is cooled directly, the cooling efficiency is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a low-noise amplifier used in radio equipment in microwave or millimeter wave bands.

In microwave or millimeter wave band wireless communications, especially in satellite communications, the received radio waves are extremely weak, so the amplifier used immediately after the receiving section (antenna) of the receiving device must be installed with an extremely low level of noise emitted by the amplifier itself. It is necessary to use a low noise amplifier.

[Conventional technology]

Conventionally, as a method for reducing the noise level of an amplifier, a method of cooling the amplifier has been generally adopted.

The structure of a conventional cooled low-noise amplifier is such that the amplifier circuit is housed in a metal casing, and this casing is cooled by a cooling device. It is. In the figure, reference numeral 1 indicates an amplifier circuit, which is an amplifier element such as an FET (field effect transistor) chip 1.
A is mounted on a carrier 1b and converted into a microwave IC (MI).The amplifier circuit 1 is housed in a metal housing 2, and has waveguides for input (IN) and output (OUT). 3.
4 via a coaxial line. The housing 2 and the waveguides 3 and 4 are housed in a case 5, and inside the case 5, electronic cooling modules 6 are arranged in multiple stages such that the low temperature side is in contact with the bottom surface of the housing 2 and the high temperature side is in contact with the case 5. be. As a result, the housing 2 is cooled, and the amplifier circuit is cooled down to -50°C.
cooled down to a certain degree. In addition, the reference numeral 7 indicates a heat insulating material packed inside the case 5, and the reference numeral 8 indicates a heat dissipation fin provided on the outer surface of the case. Since the circuit is housed in a metal casing and is indirectly cooled through the casing, it not only has a complicated structure, but also has a large heat capacity due to the large size of the parts to be cooled, including the casing. Since it is large and there is a lot of heat inflow from the outside, there is a problem that cooling efficiency is poor. In recent years, attempts have been made to reduce the size of the cooled portion as a countermeasure, such as by converting the amplifier circuit to an MIC as in the above example, but there are limits to this as well.

[Means for solving problems]

In order to solve the above-mentioned problems, the low noise amplifier according to the present invention forms a part of the waveguide into a cutoff shape, mounts an MIC amplification circuit in the cutoff shape part, and further mounts the amplification circuit in the cutoff shape. The configuration includes a cooling device that can directly cool the circuit.

[Effect]

In the above structure, the MIC amplifier circuit is mounted on the to-off shape part of the waveguide, so the structure is simple and compact.The amplifier circuit is directly cooled, so efficient cooling is possible. It is possible.

Note that if the waveguide is formed of a material with low thermal conductivity, the inflow of heat from the outside will be small, and the cooling efficiency can be further improved.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a longitudinal sectional view of an embodiment of a low noise amplifier according to the present invention. In the figure, reference numeral 10 indicates a waveguide, and FIG. 2 is a horizontal sectional view of this waveguide 10. The waveguide 10 is made of a material with low thermal conductivity, for example, a glass material,
Its surface is plated with metal. As shown in FIGS. 1 and 2, the central portion 11 of the waveguide 10 is narrowed in height and width with respect to the input and output portions at both ends, and is formed into a so-called cut-off shape. ing.

An amplifier circuit 1 is placed in the cut-off shaped portion 11 of the waveguide 10.
2 has been implemented. This amplifier circuit uses FET chip 7'1
2a'i The MIC is mounted on a carrier 12b, and the carrier 12b is mounted in a hole formed in the bottom wall of the waveguide 10. waveguide 10
Although not shown, the coupling between the amplifier circuit 12 and the amplifier circuit 12 is a well-known coupling structure such as electric field coupling using an antenna or magnetic field coupling using a loop or horn. Incidentally, the work of mounting the amplifier circuit 12 on the waveguide 10 can be easily carried out by, for example, forming the waveguide 10 into an upper and lower halves.

The waveguide 10 is housed in a case 13 with both ends fixed with seven runs 14. Then, the electronic cooling monoule 15 is installed in the case 13, with the low temperature side being the carrier 1 of the amplifier circuit 12.
2b, and are arranged in multiple stages so that the high temperature side is in contact with the case 13, respectively.゛Thus, the amplifier circuit 12 is cooled to about -50°C5).
.

◎Note that numerals 16 and 17 indicate a heat insulating material and a radiation fin, respectively.

In addition, in the embodiments shown in FIGS. 1 and 2, the cutoff-shaped portion 11 of the waveguide 10 is formed by narrowing both the height and the width in the shape of a bow. It is sufficient to narrow the width, and it is not necessarily necessary to narrow the height. However, narrowing the height also contributes to improving the coupling efficiency between the waveguide and the amplifier circuit.

Furthermore, the cutoff shape of the waveguide is not limited to the Theno f-shape. For example, the cutoff-shaped portion 11A of the waveguide 10A of the other embodiment shown in FIG. 3 has a step shape, and this can also provide substantially the same function as in the case of the Chi/4'-shape.

〔Effect of the invention〕

According to the present invention, since the amplifier circuit is mounted inside the waveguide, there is no need to use a casing for accommodating the amplifier circuit as in the conventional case, and the structure becomes extremely simple.

Furthermore, since the amplifier circuit can be directly cooled, the heat capacity of the cooled section is smaller than in the conventional case where it is indirectly cooled through a metal casing, and the cooling efficiency can be improved accordingly.

Furthermore, as described above, if the waveguide is made of a material with low thermal conductivity, the inflow of heat from the outside can be reduced, and further improvement in cooling efficiency can be realized.

[Brief explanation of the drawing]

1 and 2 are diagrams showing an embodiment of a low noise amplifier according to the present invention, with FIG. 1 being a longitudinal sectional view thereof, and FIG. 2 being a horizontal sectional view of a waveguide thereof. FIG. 3 is a horizontal sectional view of a waveguide according to another embodiment of the present invention. FIG. 4 is a longitudinal sectional view of an example of a conventional low noise amplifier. 10.10A...Waveguide, 11.11A...Cutoff shape part, 12...Amplification circuit, 12a...FE
T Chicno, 12b...Carrier, 13...Case,
14...7 lunge, 15...electronic cooling module,
16...Insulating material, 17...Radiating fin. Figure 1 Figure 3

Claims (1)

[Claims] 1. A part of the waveguide is formed into a cutoff shape, an amplification circuit formed as a microwave IC is mounted in the cutoff shape part, and a cooling device that can directly cool the amplification circuit is provided. A low noise amplifier characterized by comprising a device. 2. The low noise amplifier according to claim 1, wherein the waveguide is made of a material with low thermal conductivity. 3. The low noise amplifier according to claim 1, wherein the cooling device is an electronic cooling module.