An input-output coupler

Abstract

The invention proposes an input-output coupler, which is composed of an input coupler and an output coupler, the input coupler and the output coupler have the same structure, and are distributed at both ends of a rectangular interlaced double-gate slow-wave structure; the input coupler and the output coupler are composed of It consists of a transition section, a rectangular waveguide and a reflective isolator, the central axes of the transition section, the rectangular waveguide and the reflective isolator are parallel in the z direction, and the coupler is mirror-symmetrical about the x=0 plane. The invention adopts rectangular waveguide connected to the opening of the E surface of the rectangular interlaced double-grid slow-wave structure as input and output, and adopts a rectangular cavity reflector to isolate the electromagnetic, so that the overall structure is simple and compact, easy to process, and the port reflection coefficient is small in a wide frequency range. The isolation between electron gun and collector is high.

Description

technical field [0001] The invention relates to an input-output coupler, in particular to an input-output coupler suitable for a rectangular interlaced double-grid slow-wave structure, and belongs to the technical field of vacuum electronics. Background technique [0002] In recent years, rectangular interleaved dual-grid slow-wave structures have attracted attention in the research of millimeter-wave and terahertz sources. This slow-wave structure is obtained by placing two rows of rectangular metal grids interlaced with each other on the two broad sides of the rectangular waveguide, and leaving a certain height of electron injection channels between the upper and lower grids. After the introduction of dislocations, the fundamental mode TEx10 of the double-gate structure is no longer the y-direction antisymmetric mode, the transverse field component Ey in the electron beam channel is weakened, and the longitudinal field component Ez is strengthened, which provides favorable...

AI Technical Summary

Problems solved by technology

The main reasons for the difficulty in the design of the input-output coupler with the rectangular interleaved double-grid slow-wave structure are: (1) the rectangular waveguide is connected to the rectangular interleaved double-grid slow-wave structure, which introduces a large discontinuity of the structure and causes a large reflection; (2) ) The width of the electron beam channel is the same as the width of the slow wave structure, the signal is not cut off in it, and it is easy to leak to the electron gun and the collector, so it is necessary to try to form an electromagnetic isolation

[0004] The document "J.Q.Lai, Y.B.Gong, Y.Y.Wei, et al.W-band 1-kW staggered double vanetraveling-wave tube.IEEE Trans.Electron Devices,2012,59(2):496-503" provides a reflection coefficient Small input-output coupler with high isolation, the input-output structure mentioned in patent CN20111022781.8 (an input-output structure of a broadband phase-shifted traveling wave tube) and the patent CN20101059443.2 (a rectangular interleaved double-gate Energy coupling device with slow wave structure) The mentioned energy coupling device is composed together, the overall structure is more complicated, and the length is longer

The complex structure is due to the introduction of fine structures such as tapered double-ridge waveguides and double-ridge curved waveguides to achieve the purpose of converging electromagnetic energy, guiding electromagnetic energy and reducing reflection coefficients, which will increase the difficulty of micromachining and manufacturing costs in the terahertz frequency band; The longer length is because the slow wave structure is transitioned to the rectangular waveguide by using two rows of staggered upper and lower rows of gradual rectangular gratings, and the number of gradual rectangular gratings in the transition section needs to be large enough (5 pairs or more than 10) to obtain the reflection that meets the needs of engineering applications coefficient, which will increase the difficulty of focusing the ribbon electron beam under the condition of low voltage and high current density

In addition, in order to obtain a good isolation between the electron gun and the collector, when inserting the electron beam channel into the curved waveguide, it is necessary to reduce the size of the channel so that the electromagnetic wave can be cut off in it, which will limit the current passing under a certain current density or increase the interception of electrons by the channel. probability

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