Input/output coupler

Abstract

The invention provides an input / output coupler which is composed of an input coupler and an output coupler. The input and output couplers are the same in structure, and distributed in the two ends ofa rectangular interlaced double-gate slow wave structure respectively; each coupler is composed of a transition section, a rectangular waveguide and a reflection isolator which are parallel with one another in the direct z of the central axis; and the couplers are in planar mirror symmetry by taking x=0 as the center. An E-surface opening connecting rectangular waveguide of the rectangular interlaced double-gate slow wave structure serves as input and output, the rectangular cavity reflector isolates electromagnetism, the whole structure is simple, compact and easy to process, the port reflection coefficient within the broadband scope is low, and the isolated degree for an electronic gun and collector are 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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