JPS60247302A - High power type coaxial waveguide converter - Google Patents

Abstract

PURPOSE:To obtain a high power type coaxial waveguide converter which can secure the high power resistance performance under the normal temperature, by increasing the width of the broad surface of a waveguide at the conversion part compared with the width of the broad surfaces at other areas. CONSTITUTION:The width a2 of a broad surface 2A of a waveguide 2 is increased at a conversion part 1 compared with the width a1 of other area. For instance, the width a1 of a broad surface 2A of the waveguide 2 of WRJ-10 is set at 22.9mm. together with the width b1 of a narrow surface set at 10.2mm. respectively. Then the width a2 of the surface 2A is increased to 30mm. at the part 1. As a result, the characteristic impedance of the waveguide 2 is reduced and approximates to that of a coaxial line 3. If a conical regeneration element 4 is used under such conditions, the matching is facilitated. Furthermore the degree of concentration is reduced since the width of the surface 2A is increased in terms of the distribution of electric field. In this way, the voltage breakdown is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a high-power waveguide converter that converts between a coaxial mode and a waveguide mode.

(Prior art) When using a coaxial mode (TEM mode) and waveguide mode (TE mode) converter used in the microwave band as a high power transmission element, the following functions are required: (a) low reflection; (1) Low loss per unit; (3) High power resistance.

Conventional coaxial waveguide transducers are generally doorknob type as shown in FIG. 2 and ridge guide type as shown in FIG. 3. The doorknob-shaped coaxial waveguide converter shown in FIG. A conical transformation element 4 is connected to the central conductor 3B that protrudes from the center conductor 3B. The ridge guide type coaxial waveguide converter shown in FIG. 3 has a structure in which a ridge guide type transformation element 5 is disposed within a waveguide 2 in a conversion section 1 and a center conductor 3B is connected. . Note that 6 is an end plate.

All such coaxial waveguide converters are characterized by the impedance transformation method, and can satisfy the functions of low reflection and low loss.

(Problems to be Solved by the Invention) However, all coaxial waveguide converters have the drawback that high power durability cannot be obtained under normal pressure. One of the reasons for this is that the impedance transformation section also serves as a mode conversion section, and electric field concentration that leads to voltage breakdown is likely to occur. For example, when a coaxial waveguide converter consisting of a waveguide called WRJ-10 and a hollow coaxial line with an inner conductor outer diameter of 6 mm and a characteristic impedance of 36 Ω is realized in the shape of a doorknob, the withstand power under normal pressure is the peak power. The power output is 120KW, and the power output is 90KW when realized in the ridge guide type. Therefore, when transmitting higher power, it is known that the converter has an airtight structure and is pressurized to increase the power resistance. For example, an increase of 1 atm will theoretically increase the withstand power by 4
It increases twice. Although such a converter can provide higher power resistance, it has drawbacks such as a complicated structure and the need for a pressurizing device.

(Objective of the Invention) An object of the present invention is to provide a high-power coaxial waveguide converter that can obtain high power durability under normal pressure.

(Means of the Invention for Solving Problems) The present invention provides a coaxial mode to waveguide mode converter in which the width of the wide surface of the waveguide in the conversion section is made wider than the width of the wide surface in other parts. This is a characteristic feature.

(Operation of the Invention) When the width of the wide surface of the waveguide is made wider than the width of the other portions of the wide surface in the conversion section in this way, the characteristic impedance of the waveguide decreases and approaches the characteristic impedance of a coaxial line. In addition, since the width of the wide surface of the waveguide is wide, the electric field distribution is less concentrated, making voltage breakdown less likely to occur, and improving power durability.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to FIG. Note that parts corresponding to those in FIG. 2 are designated by the same reference numerals. In the high power type coaxial waveguide converter of this example,
In the converter 1, the width a2 of the wide surface 2A of the waveguide 2 is made wider than the width a1 of the wide surface of the squared portion. For example, the waveguide 2 is a WRJ-10 waveguide, and the width a1 of the wide surface 2A is 22.9 mm and the width b1 of the narrow surface is 10.2#+#I. width a2 of 3ONIR
It is expanding to Further, for example, the coaxial line 3 is a coaxial line with a characteristic impedance of 36Ω, the inner diameter of the outer conductor 3A is 1111 m, and the outer diameter of the center conductor 3B is 6#.

When the width of the wide surface 2A of the waveguide 2 is increased in the converter 1 in this way, the characteristic impedance of the waveguide 2 decreases and approaches the characteristic impedance of the coaxial line 3.

In this state, if the inner conical transformation element 4 is used, alignment can be easily achieved. Furthermore, since the width of the wide surface 2A of the waveguide 2 is wide, the electric field distribution is less concentrated and voltage breakdown is less likely to occur.

When the power resistance of a coaxial waveguide converter having the above dimensions was measured, it withstood a peak power of 200 KW under normal pressure.

(Effects of the Invention) In the coaxial waveguide converter according to the present invention, since the width of the wide surface of the waveguide in the conversion section is made wider than the width of the wide surface in other parts,
The characteristic impedance of the waveguide is lowered, making it possible to approach the characteristic impedance of a coaxial line. In addition, since the width of the wide surface of the waveguide is widened in the conversion section, the electric field distribution is less concentrated, making voltage breakdown less likely to occur, and making it possible to significantly improve power durability under normal pressure compared to conventional products. Furthermore, the present invention eliminates the need for an airtight structure and a pressurizing device, which is economically advantageous.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view of an embodiment of a coaxial waveguide converter according to the present invention, and FIGS. 2 and 3 are partially cutaway perspective views of two examples of conventional converters. . 1... Conversion section, 2... Waveguide, 2A... Wide surface, 2
B... Narrow surface, 3... Coaxial line, 3A... Outer conductor, 3B... Center conductor, 4... Conical transformation element.

Claims (1)

[Claims] A high-power coaxial waveguide converter for coaxial mode and waveguide mode, characterized in that the width of the wide surface of the waveguide in the conversion section is wider than the width of the wide surface in other parts.