Metamaterial high-power microwave source

Abstract

A metamaterial high-power microwave source relates to the fields of vacuum electronic technology, particle physics, and accelerators, including: a cathode, a metamaterial slow-wave structure (SWS), a waveguide and coaxial line coupler located at one end of the metamaterial SWS and a collector component located at the other end of the metamaterial SWS. The metamaterial SWS provided by the present invention is greatly smaller than a rectangular waveguide having the same frequency, so as to realize a miniaturization of devices and facilitate integration with semiconductor devices. The waveguide and coaxial line coupler has a good transmission characteristic and a low reflection in a relatively wide frequency band, which guarantees a high-efficient coupling output of a signal. Moreover, the metamaterial high-power microwave source has a high-power output and a pulsed output power reaching a megawatt level.

Claims

1. A metamaterial high-power microwave source, comprising: a cathode, a metamaterial slow-wave structure (SWS), a waveguide and coaxial line coupler which is located at one end of said metamaterial SWS, and a collector component which is located at the other end of said metamaterial SWS, wherein: said metamaterial SWS comprises a square waveguide and a metamaterial which is fixed at a central position of an inner cavity of said square waveguide; said waveguide and coaxial line coupler comprises a coupling waveguide and a coaxial line; said coupling waveguide comprises a rectangular coupling waveguide, a waveguide baffle which is located at one end of said rectangular coupling waveguide, and a waveguide connecting flange which is located at the other end of said rectangular coupling waveguide for fixedly connecting said rectangular coupling waveguide with said square waveguide; said coaxial line comprises a coaxial probe, two coaxial media, a medium fixing cylinder, and an output transferring cylinder; a central position of a lateral surface of said rectangular coupling waveguide has a circular hole thereon; one end of said medium fixing cylinder is embedded in an external side of said circular hole; the other end of said medium fixing cylinder is embedded in said output transferring cylinder; said medium fixing cylinder is filled with said two coaxial media; one end of said coaxial probe is fixedly connected with said metamaterial; and the other end of said coaxial probe passes through said two coaxial media; and said waveguide baffle has a pyramid-shaped square hole thereon for an electron beam to pass through; and said cathode is located at an external side of said square hole.

2. The metamaterial high-power microwave source, as recited in claim 1, wherein said collector component comprises a collector and a collector fixing cylinder for fixing said collector and said square waveguide.

3. The metamaterial high-power microwave source, as recited in claim 1, wherein two ends of said metamaterial respectively exceed said square waveguide by a quarter of a period length of a metamaterial unit cell.

4. The metamaterial high-power microwave source, as recited in claim 1, wherein adjustable gaskets are provided between said waveguide baffle and said rectangular coupling waveguide, for adjusting a position of said square hole.

5. The metamaterial high-power microwave source, as recited in claim 1, wherein said two coaxial media are made of polytetrafluoroethylene.

6. The metamaterial high-power microwave source, as recited in claim 1, wherein said two coaxial media are divided into two sections having different external diameters; an external diameter of a first section which is close to said circular hole of said rectangular coupling waveguide is larger than an external diameter of a second section.

7. The metamaterial high-power microwave source, as recited in claim 1, wherein said output transferring cylinder has a flange at an end.

8. The metamaterial high-power microwave source, as recited in claim 1, wherein said electron beam is a sheet electron beam or a multi-electron beam.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a structural sketch view (X-Z sectional view) of a metamaterial unit cell according to prior art.

(2) FIG. 2 is a diagram of an interaction impedance changing with a frequency according to the prior art.

(3) FIG. 3 is a first structural sketch view (X-Z sectional view) of a metamaterial high-power microwave source according to a preferred embodiment of the present invention, wherein a central axis of the metamaterial high-power microwave source overlaps with a coordinate axis Z.

(4) FIG. 4 is a second structural sketch view (Y-Z sectional view) of the metamaterial high-power microwave source according to the preferred embodiment of the present invention.

(5) FIG. 5 is a structural sketch view (X-Z sectional view) of a waveguide and coaxial line coupler according to the preferred embodiment of the present invention.

(6) FIG. 6 is a diagram of a transmission coefficient amplitude changing with the frequency according to the preferred embodiment of the present invention.

(7) FIG. 7 is a diagram of a reflection coefficient amplitude changing with the frequency according to the preferred embodiment of the present invention.

(8) FIG. 8 is a diagram of a pulsed output power changing with time according to the preferred embodiment of the present invention.

(9) In the figures, 1-metamaterial SWS, wherein: 1-1-metamaterial; and 1-2-square waveguide; 2-waveguide and coaxial line coupler, wherein: 2-1-waveguide connecting flange; 2-2-rectangular coupling waveguide; 2-3-waveguide baffle; 2-4-coaxial probe; 2-5-medium fixing cylinder; 2-6-coaxial medium A; 2-7-coaxial medium B; 2-8-output transferring cylinder; and 2-9-adjustable gaskets; 3-cathode; and 4-collector component, wherein: 4-1-collector fixing cylinder; and 4-2-collector.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(10) The present invention is further illustrated with the accompanying drawings and preferred embodiments.

(11) Referring to FIG. 3-FIG. 8, according to a preferred embodiment of the present invention, a sheet beam metamaterial high-power microwave signal generator which works in a frequency band ranging from 2.85 GHz to 2.95 GHz is provided.

(12) A metamaterial 1-1 is made of oxygen-free copper (OFC). The metamaterial 1-1 has 20 periods and a length of 290 mm. A structural sketch view of each period is showed in the FIG. 1. According to the preferred embodiment of the present invention, a=14.5 mm, b=13.5 mm, h.sub.1=4.25 mm, h.sub.2=4 mm, g=1 mm, j=1.5 mm, d=1 mm; a thickness of the metamaterial 1-1 is 1.2 mm. A square waveguide 1-2 is made of OFC and has a length of 282.75 mm. A cross section of the square waveguide 1-2 is square. An inner side length of the square waveguide 1-2 is 14.5 mm. Two ends of the metamaterial 1-1 respectively exceed the square waveguide 1-2 by a quarter of a period length of the metamaterial 1-1.

(13) A waveguide connecting flange 2-1 is made of OFC, for fixedly connecting the square waveguide 1-2 with a rectangular coupling waveguide 2-2.

(14) The rectangular coupling waveguide 2-2 is made of OFC. A cross section of the rectangular coupling waveguide 2-2 is square. An inner side length of the rectangular coupling waveguide 2-2 is 60 mm. The rectangular coupling waveguide 2-2 has a length of 50 mm.

(15) A waveguide baffle 2-3 is made of OFC and has a pyramid-shaped square hole at a center of the waveguide baffle 2-3 for an electron beam to pass through. The electron beam is embodied as a sheet electron beam according to the preferred embodiment of the present invention.

(16) A coaxial probe 2-4 is made of OFC and has a diameter of 1.2 mm. The coaxial probe is divided into an arc section and a straight section, wherein: the arc section is a quadrant having an external diameter R of 23.8 mm; and the straight section has a length of 40.3 mm. The straight section of the coaxial probe 2-4 passes through a coaxial medium A 2-6 and a coaxial medium B 2-7. An end of the straight section has a cylindrical hollow part which has a length of 6 mm and an internal diameter of 0.8 mm.

(17) A medium fixing cylinder 2-5 is made of OFC and filled with the two coaxial media, 2-6 and 2-7, having different external diameters. One end of the medium fixing cylinder 2-5 is embedded in a circular hole on a lateral surface of the rectangular coupling waveguide 2-2, for fixing the coaxial media 2-6 and 2-7. A distance L between a step of the medium fixing cylinder 2-5 and an inner surface of the rectangular coupling waveguide 2-2 is 7 mm. The coaxial medium A 2-6 and the coaxial medium B 2-7 are made of polytetrafluoroethylene and have the same internal diameter of 1.2 mm. The coaxial medium A 2-6 has the external diameter of 5.4 mm and a length of 18 mm. The coaxial medium B 2-7 has the external diameter of 4.4 mm and a length of 8.5 mm. The coaxial medium A 2-6 and the coaxial medium B 2-7 can be integrated.

(18) An output transferring cylinder 2-8 is made of stainless steel and has a length of 14.5 mm. One end of the output transferring cylinder 2-8 is embedded into the medium fixing cylinder 2-5; the other end of the output transferring cylinder 2-8 has a connecting flange for connecting with external devices and outputting a signal.

(19) Adjustable gaskets 2-9 are made of OFC, for adjusting a relative deviation between the pyramid-shaped square hole and the metamaterial 1-1. According to the preferred embodiment of the present invention, the relative spacing between a cathode 3 and the metamaterial 1-1 is 2.1 mm.

(20) The cathode 3 is made of stainless steel. An emission surface of the cathode 3 has a size of 12 mm2 mm.

(21) A collector fixing cylinder 4-1 is made of OFC. A collector 4-2 is made of graphite. An X-Y cross section of the graphite is square, having a side length of 15 mm and a Z-directional thickness of 10 mm.

(22) Through a simulation, namely replacing a collector component by the waveguide and coaxial line coupler and simulating scattering parameters within the frequency band ranging from 2.85 GHz to 2.95 GHz, it is obtained that |S.sub.21| is about 2 dB and |S.sub.11| is about 10 dB. Thus, the sheet beam metamaterial high-power microwave signal generator has a good transmission characteristic (as shown in FIG. 6) and a low reflection characteristic (as shown in FIG. 7). Moreover, through simulating a nonlinear beam wave interaction, namely under a condition that the sheet electron beam has a voltage of 220 kV and a beam current of 2.75 kA, it is obtained that a pulsed output power of the microwave signal generator is about 8 MW (as shown in FIG. 8).

(23) One skilled in the art will understand that the embodiment of the present invention as shown in the drawings and described above is exemplary only and not intended to be limiting.

(24) It will thus be seen that the objects of the present invention have been fully and effectively accomplished. Its embodiments have been shown and described for the purposes of illustrating the functional and structural principles of the present invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.