CN112928412A

CN112928412A - Compact matching load

Info

Publication number: CN112928412A
Application number: CN202110353535.7A
Authority: CN
Inventors: 王清源
Original assignee: Chengdu Jihengte Technology Co ltd
Current assignee: Wuxi Carbon Technology Co ltd
Priority date: 2021-04-01
Filing date: 2021-04-01
Publication date: 2021-06-08

Abstract

The invention discloses a design scheme of a compact matching load. A short rectangular absorbing material is utilized and placed near a short-circuit end of a short-circuit rectangular waveguide, and then a plurality of screws are set on the upper surface of the rectangular waveguide to widen the bandwidth of the compact matching load and reduce the reflection coefficient in the working frequency band of the compact matching load. The rectangular absorbing material has the advantages of low processing cost and high processing yield, and is not easy to crack like a wedge-shaped absorbing body after absorbing microwaves to reach high temperature. The use of a stainless steel waveguide of relatively low thermal conductivity and a heat sink of high thermal conductivity can effectively reduce the temperature of the compact matched-load flange and other waveguide devices connected thereto. The compact matching load has the characteristics of small volume, large power capacity, low manufacturing cost and the like, and can be widely applied to the fields of high-power radio frequency microwave accelerators, microwave energy heating and the like.

Description

Compact matching load

Technical Field

The invention relates to a compact matched load. In particular to a high-power miniaturized waveguide matched load formed by utilizing a bulk absorber and a screw.

Background

Compared with the traditional waveguide load, the compact waveguide matching load has the advantages of simplified structure, greatly reduced weight, reduced installation volume, high power and high performance in various microwave systems, particularly in radio frequency microwave accelerators, radio frequency microwave heating systems and the like. The shape of the absorption material used by the traditional waveguide matching load is wedge-shaped, the length is several wavelengths, and a longer rectangular waveguide is required. When microwaves are incident into the matched load, the microwave energy is primarily lost to the tip portion of the absorbing material closest to the waveguide flange. In order to reduce the temperature of the waveguide flange and other waveguide devices connected thereto, it is necessary to further increase the length of the rectangular waveguide. Therefore, the power-transmitting high-power waveguide is long in matched load. The wedge-shaped absorbent material also has problems of high processing cost and low yield. Meanwhile, the tip of the absorbing material is also the place which is most easily broken and damaged due to overheating in the high-power matching load, and the service life of the rectangular waveguide matching load is directly influenced.

Disclosure of Invention

The invention aims to provide an economical and compact high-power waveguide matching load. In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a compact matched load includes a length of rectangular waveguide short-circuited at its rear end face in the Z direction, an absorber on a lower inner surface in the-Y direction in the rectangular waveguide, and at least one screw on an upper inner surface in the Y direction in the rectangular waveguide. The depth of the screw extending into the rectangular waveguide from the outside of the rectangular waveguide can be adjusted and fixed from the outside of the rectangular waveguide. The X, Y direction and the Z direction form a rectangular coordinate system.

To try to shorten the overall length of the compact matched load, we use as short an absorber as possible: the maximum dimension of the absorber in the Z-direction is smaller than the operating wavelength of the microwave in vacuum. In a preferred embodiment, the maximum dimension of the absorber in the Z direction may be less than half of the operating wavelength of the microwave in vacuum, or even less than one third of the operating wavelength of the microwave in vacuum.

In order to solve the problems of high processing cost and easy cracking at high power of the absorber, the absorber is shaped as a cuboid.

The number of screws is at least three in order to minimize the reflection coefficient of the input end of the compact matched load over a wide frequency range using a shorter absorber. In order to realize the compact matching load which is as short as possible, the distance between the central line of all the screws and the short-circuit end of the rectangular waveguide along the Z direction is smaller than the operating wavelength of microwaves in vacuum. In a preferred design, the distance between the central line of all the screws and the short-circuit end of the rectangular waveguide along the Z direction is less than three-quarters of the operating wavelength of the microwave in vacuum.

In order to facilitate the communication of the compact matching load with other waveguide devices, a flange is arranged on the end face of the rectangular waveguide along the-Z direction.

In order to solve the problem that the compact matching load is short, the absorbing material is close to the flange, so that the flange is overheated, and the temperature of other waveguide devices connected with the compact matching load is increased, the rectangular waveguide is made of a material with low thermal conductivity. In a preferred design, the rectangular waveguide is made of stainless steel.

In order to guide the heat generated by the absorber as far as possible and prevent the compact matching load from overheating, a heat sink is arranged outside the part of the rectangular waveguide connected with the absorber. In a preferred design, the material of the heat sink is a material with relatively high thermal conductivity, such as aluminum alloy or copper alloy.

The invention has the following beneficial effects:

the invention discloses a design scheme of a compact matching load. We utilize a very short rectangular absorbing material and place it near the short end of a short-circuited rectangular waveguide, then set several screws on the upper surface of the rectangular waveguide to broaden the bandwidth of the compact matched load, reducing the reflection coefficient within its operating band. The rectangular absorbing material has the advantages of low processing cost and high yield, and is not easy to crack like a wedge-shaped absorbing body after absorbing microwaves to reach high temperature. The use of a stainless steel waveguide of relatively low thermal conductivity and a heat sink of high thermal conductivity can effectively reduce the temperature of the compact matched-load flange and other waveguide devices connected thereto. The compact matching load has the characteristics of small volume, large power capacity, low manufacturing cost and the like, and can be widely applied to the fields of high-power radio frequency microwave accelerators, microwave energy heating and the like.

Drawings

FIG. 1 is a schematic end view of the present invention

FIG. 2 is a schematic cross-sectional view along the AA direction in FIG. 1

FIG. 3 is a schematic view of the BB direction in FIG. 1

The reference numbers in the drawings correspond to the names: 1-rectangular waveguide, 2-absorber, 3-screw, 4-flange and 5-radiating fin.

Some of the terms specified in this specification are as follows:

upper, i.e. Y-direction, and lower, i.e. -Y-direction. The rear, i.e. the Z-direction. The X direction, the Y direction and the Z direction form a rectangular coordinate system.

The central line of the screw refers to the axis of the cylindrical screw.

Detailed Description

Example 1

As shown in figures 1 to 3.

A compact matched load comprises a rectangular waveguide 1 with a short-circuited rear end face in a Z direction, an absorber 2 on a lower inner surface in a-Y direction in the

rectangular waveguide

1, and 3 screws 3 on an upper inner surface in the Y direction in the rectangular waveguide 1. The depth of the screw 3 protruding from the rectangular waveguide 1 into the rectangular waveguide 1 can be adjusted and fixed from the rectangular waveguide 1. The X, Y direction and the Z direction form a rectangular coordinate system.

The maximum dimension of the absorber 2 in the Z direction is less than half the operating wavelength of the microwaves in vacuum

The absorber 2 is shaped as a rectangular parallelepiped.

The distance between the central line of all the screws 3 and the short-circuit end of the rectangular waveguide 1 along the Z direction is less than three-quarters of the operating wavelength of the microwave in vacuum.

And a flange plate 4 is also arranged on the end surface of the rectangular waveguide 1 along the-Z direction. The rectangular waveguide 1 is made of stainless steel. The radiating fins 5 are made of aluminum alloy.

The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner. According to the technical spirit of the present invention, any simple modification, equivalent replacement, and improvement made to the above embodiments within the spirit and principle of the present invention still fall within the protection scope of the technical solution of the present invention. For example, the cavity may be in the shape of a rectangular parallelepiped, a cylinder, or the like.

The X, Y and Z directions herein constitute a rectangular coordinate system. The X-direction, Y-direction, and Z-direction are referred to herein as any three mutually perpendicular directions, and are provided merely for convenience in explaining the innovative concepts of the present invention. The compact matching load provided by the invention can be arbitrarily translated and integrally rotated in an actual three-dimensional space, and the innovation and the advancement of the compact matching load are not influenced.

Claims

1. A compact matched load, comprising a length of rectangular waveguide (1) short-circuited at its rear end face in the Z-direction, an absorber (2) on the lower inner surface in the-Y direction in the rectangular waveguide (1), and at least one screw (3) on the upper inner surface in the Y direction in the rectangular waveguide (1); the depth of the screw (3) extending from the rectangular waveguide (1) into the rectangular waveguide (1) can be adjusted and fixed from the outside of the rectangular waveguide (1). The X, Y direction and the Z direction form a rectangular coordinate system.

2. A compact matched load according to claim 1, wherein the largest dimension of said absorber (2) in the Z-direction is smaller than the operating wavelength of microwaves in vacuum.

3. A compact matched load according to claim 1, wherein the largest dimension of said absorber (2) in the Z-direction is less than half the operating wavelength of microwaves in vacuum.

4. A compact matched load according to claim 1, wherein the largest dimension of said absorber (2) in the Z-direction is less than one third of the operating wavelength of microwaves in vacuum.

5. A compact matched load according to claim 1, wherein the number of said screws (3) is at least three; the distance between the central line of all the screws (3) and the short-circuit end of the rectangular waveguide (1) along the Z direction is smaller than the operating wavelength of microwaves in vacuum.

6. A compact matched load according to claim 1, wherein the number of said screws (3) is at least three; the distance between the central line of all the screws (3) and the short-circuit end of the rectangular waveguide (1) along the Z direction is less than three-quarters of the operating wavelength of the microwave in vacuum.

7. A compact matched load according to claims 1 to 6, wherein said absorber (2) is in the shape of a cuboid.

8. A compact matched load according to claim 7, wherein the material of said rectangular waveguide (1) is stainless steel.

9. A compact matched load according to claim 8, wherein a heat sink (5) is provided outside the part of the rectangular waveguide (1) connected to the absorber (2); the radiating fins (5) are made of aluminum alloy or copper alloy.

10. A compact matched load according to claim 9, wherein a flange (4) is further provided at the end face of said rectangular waveguide (1) in the-Z direction.