Patent ID: 12207384

In the drawings:1—feed waveguide;2—brim;3—metal base;4—sub-waveguide;5—radiation slot;6—first platform;7—first section of steps;8—second platform;9—second section of steps.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The following clearly and completely describes the technical solutions in the embodiments of the present disclosure with reference to the accompanying drawings in the embodiments of the present disclosure. Apparently, the described embodiments are merely a part rather than all of the embodiments of the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present disclosure without creative efforts shall fall within the protection scope of the present disclosure.

An objective of the present disclosure is to provide a top surface wave antenna of a spherical Tokamak to solve the problem of density limit involved in current driving of low-hybrid wave external antenna of a small Tokamak in the prior art, such that the surface wave antenna and a peripheral antenna are supplementary to each other. The surface wave antenna is stable in performance and good in testing result, and conforms to experimental requirements.

To make the objectives, features and advantages of the present disclosure more apparently and understandably, the present disclosure is further described in detail with reference to accompanying drawings and specific embodiments.

As shown inFIG.1toFIG.5, the embodiment provides a top surface wave antenna of a spherical Tokamak, comprising a feedback waveguide1, a brim2, sub-waveguides4, and a metal base3. The lower end of the feed waveguide1is connected to one end of the metal base3, and one side of the feed waveguide is connected to the brim2. The brim2is towards a length direction of the metal base3. A plurality of sub-waveguides4are arranged on the metal base3at equal intervals, the tops of the sub-waveguides4are not higher than the height of the metal base3, and the sub-waveguides4are arranged in a rising line trend. The feed waveguide1serves as a microwave input port.

A through opening of the feed waveguide1is rectangular and has only a left input port. Only a reflection coefficient needs to be focused during an experiment. The top surface of the feed waveguide1is flush with the top end of the metal base3, and the initial height of the sub-waveguide4is not higher than the bottom surface of the feed waveguide1. The brim2is an inverted U shape, the top surface of the brim2is flush with the top surface of the feed waveguide1, the two side surfaces of the brim are right triangles, and the two side surfaces of the brim are connected to the side wall of the feed waveguide1. The arrangement of the brim2is more conducive to the uniform conduction of the microwave.

Two platforms and two sections of steps are arranged on the metal base3. A first platform6, a first section of steps7, a second platform8and a second section of steps9are connected in sequence. The sub-waveguides4arranged on the first platform6, the first section of steps7and the second platform8have the same height, and the top ends of the sub-waveguides4on the second section of steps9are flush with the top ends of the sub-waveguides4on the second platform8. Each step of the first section of steps7has a height of 3.38 mm, and each step of the second section of steps9has a height of 5 mm. The height of each step is not equal to the height of the sub-waveguide4, and the thicknesses of the sub-waveguides4are consistent, such that the radiation performance of the antenna is better and more accurate. The arrangement of the steps is more conducive to the crawling of microwaves.

A radiation slot5between the adjacent sub-waveguides4has a width of 0 mm to 100 mm. The number of the sub-waveguides4is 0 to 100, and the sub-waveguides4each have a thickness of 0 mm to 100 mm and a height of 0 mm to 100 mm. According to the transmission line principle, the performance of the antenna and the setting of the reflection coefficient, the thickness and the number of the sub-waveguides4and the spacing distance between the adjacent sub-waveguides can be properly changed. In the embodiment, the number of the sub-waveguides4is 27, the number of the radiation slots5is 28, the radiation slots5formed in the first platform6, the first section of steps7and the second platform8each have a depth of 0 to 100 mm, preferably 27 mm to 28 mm, the sub-waveguides4each have a thickness of 0 to 100 mm, preferably 5 mm, and a spacing distance between the adjacent sub-waveguides4is 0 to 100 mm, preferably 5 mm.

The total length of the feed waveguide1and the metal base3is not greater than 240 mm, and the top surface wave antenna has a parallel refractive index n11of 0 to 10. In accordance with the embodiment, the antenna has a dimension of 210 mm in a microwave transmission direction. Due to the fact that the top antenna needs to extend into a metal cylinder having a diameter of 240 mm to reach a plasma region, the length of the antenna cannot exceed 240 mm, and the width of the antenna can be set according to actual needs. The feed waveguide1, the brim2, the sub-waveguide4and the metal base3are made of, but not limited to, copper, aluminum, iron, or stainless steel. The sub-waveguide4and the metal base3may be integrally machined and manufactured.

In accordance with the embodiment, the top surface wave antenna of the spherical tokamak and a peripheral antenna supplement each other and work together. One port is used for the input of microwaves, the other port is used for the output of microwaves. The antenna generates plasmas through saw teeth, slots and radiation energy, and is mainly used in a high-average-power microwave system, especially low-hybrid wave driving of the Tokamak, where the thickness of the sub-waveguide4, the depth of the radiation slot5and the height of the step supplement each other to jointly determine the performance, the reflection coefficient, the field intensity distribution, the parallel refractive index and the like of the antenna. The antenna, after being machined and molded, is debugged to achieve the engineering requirement, with an excellent experimental test result.

As shown inFIG.4, an actual testing diagram of reflection coefficients of an antenna in accordance with the present disclosure is provided. The testing result may vary slightly with the change of the machining materials (gold, silver, copper, aluminum, stainless steel and the like). The antenna has a central operating frequency of 2.45 GHz, S11(reflection coefficient) at the point is equal to −17 dB, about 99% microwave energy is radiated into the air, less than 1% of the energy is reflected back from the port of the feeder waveguide1, and the microwave bandwidth is 6 MHz. As shown inFIG.5, a diagram illustrating parallel refractive indexes of an antenna in accordance with the present disclosure is provided. The antenna has a central operating frequency of 2.45 GHz, n11(parallel refractive index) at the point is equal to 3.6, and the parallel refractive rate n11related to the antenna is equal to 0 to 100. It is shown in the figure that the top surface wave antenna is excellent in directivity.

Several examples are used for illustration of the principles and implementation methods of the present disclosure. The description of the embodiments is merely used to help illustrate the method and its core principles of the present disclosure. In addition, a person of ordinary skill in the art can make various modifications in terms of specific embodiments and scope of application in accordance with the teachings of the present disclosure. In conclusion, the content of this specification shall not be construed as a limitation to the present disclosure.