Analysis of Loss and Dispersion Characteristics for Groove Guides with Arbitrary Groove Profiles by an Equivalent Active Transmission Line Method*

Loss and dispersion characteristics of groove guide are two practically important factors in the design for millimeter wave system consisting of groove guide. In this paper, a new method is presented for analyzing loss and dispersion characteristics of the groove guides with arbitrary groove cross-sections. The method is based on the combination of an equivalent active transmission line equation and the staircase approximation. Numerical results of dispersion and attenuation properties for some groove guides with different groove profiles are given. The effectiveness and practicality of the present analysis are confirmed by the data given in the literature.*Supported by the National Natural Science Foundation of China (No. 60171019) and (No. 60371010)     

Finite-element analysis of dispersion and loss characteristics of groove guide with arbitrary shapes

The dispersion and loss characteristics of groove guide with arbitrary shapes are analyzed with high-order finite element method. The effectiveness and the reliablity of the method are verified by the experiments and the results obtained by other methods. Groove guides with various groove shapes, such as rectangular, triangular, parabolic, elliptic and cosine functions, are investigated systematically. The calculating results show that the dispersion of groove guide with different groove shape is almost the same, however, the loss characteristics is rather different; among them, V-shape groove guide has the lowest loss which is about half of the rectangular one. All the curves and the data given in this paper can be used in designing elements and circuits of the groove guide.     

Finite Element Analysis of Field Pattern in Multiple Groove Guide

Rectangular groove guide with multiple grooves has been analyzed by finite element method (FEM) in this paper. The electrical field patterns of the dominant mode and the first higher-order TE mode have been presented for groove guide with single-, double-, triple-, and quadruple-rectangular grooves. The electromagnetic field of the dominant mode is distributed with a concentration in the groove regions, while the electromagnetic field of the first higher-order TE mode is mainly distributed in regions between grooves. The low loss characteristic has been found not only in single-groove guide, but also in multiple groove guide.     

Design of EPU oscillator cavity in femtosecond accelerator

We adopt the groove guide as the cavity of the undulator to reduce the diffraction effect. The groove guide has the advantages of lower surface energy loss, larger power capacity, less modes, and larger structure dimension over the traditional method waveguide. The attenuation calculation is given in this paper including the cavity optimization. And the dispersive character indicates that the oscillator can work in different modes with the change of the electron beam energy.     

Design of EPU oscillator cavity in femtosecond accelerator

We adopt the groove guide as the cavity of the undulator to reduce the diffraction effect. The groove guide has the advantages of lower surface energy loss, larger power capacity, less modes, and larger structure dimension over the traditional method waveguide. The attenuation calculation is given in this paper including the cavity optimization. And the dispersive character indicates that the oscillator can work in different modes with the change of the electron beam energy.     

Dominant mode characteristics of circular groove guide

Circular groove guide is a kind of waveguide for millimeter waves with low loss, large dimensions, and low dispersion. In this paper, the dominant mode characteristics of it is analysed. The technique that mode macthing method combines with point matching method is used to derive the Nth-order characteristic equation of the guide. The 1st order, 2nd order and 3rd order approximate curves that the normalized cutoff wavelength of circular groove guide varies with c/a are given. The attenuation curves are given at 1mm, 1.5mm and 3mm wavelength. The numerical results are in well agreement with the experimental results published.Supported by National Science Foundation of P. R. China     

Finite Element Analysis of the Dominant Mode Variation in Groove Guide

In this paper, the dominant mode in groove guide is analyzed by finite element method. For the guide with a shallow groove, the electric field lines (abbreviated as E lines) are perpendicular to the parallel plate, which is different from the literatures, and the dominant mode distribution is irrelevant to the groove width; for the guide with a narrow but deeper groove, the E lines are parallel to the plate region, which represents the characteristics of lower attenuation, for the guide with a deeper and wider groove, a complicated E lines are obtained. These results reveal that the dominant mode distribution in groove guide is varied, which replenish our understanding of groove guide, and the results have important values in design, manufacture, and application of groove guide.     

Analysis for a Novel Cocoon-Shaped Groove Guide with Method of Lines

An arbitrarily cross-sectional groove guide is analyzed by using the method of lines and its characteristic equations are gives for TE and TM modes. Some numerical results show that correctness of the method of lines compared with the relevant results in the references is verified, and it is convenient to solve groove guide with arbitrary shape in practical application problems. A novel cocoon-shaped groove guide is firstly presented and its transmission characteristics are analyzed and discussed. The new type of cocoon-shaped groove guide has the good performances. The obtained results are of important application values in theoretical studies and practical applications of groove guides for millimeter waves.     

The solution of the characteristic equation of circular-rectangular groove guide

Circular-rectangular groove guide is a new type of structure we have presented for coupling between circular groove guide and rectangular groove guide. In this paper, as the continuity of our previous work, the characteristic equation of circular-rectangular groove guide has been solved and the numerical results have been given and discussed.The Project Supported by National Natural Science Foundation of P. R. China     

A New Fourier''s Expansion-Differential Method for Analyzing Groove Guide with Arbitrary Shape

A new Fourier's expansion-differential method for analyzing groove guide with arbitrary shape is firstly presented in this paper. It is convenient to solve practical application problems of arbitrary groove guides. The calculated results of the guide wavelengths of typical groove guides are in good agreement with ones in references, and its computing precision is fairly high. Hence the computational correctness of the new method is verified. The new method has the advantages of clear conception, direct-viewing expression, simple and easily feasible computation, etc. So it is of important application values for enriching groove guide theory and is solving actual engineering application problems for millimeter waves.     

Groove guide and H-guide: Supplementary information

Interest in groove guide and H-guide for application at millimeter waves is considerable at present. Hitherto unpublished material dealing with these waveguides is presented. The early history, patent applications, drawings and prototypes are described.     

LEAKY CHARACTERISTICS OF A NEW MILLIMETER WAVE ANTENNA BASED ON GROOVE GUIDE WITH AN ASYMMETRIC CONDUCTOR STRIP

A new millimeter wave leaky wave antenna is presented in this paper, which is a modification of the groove guide with an asymmetric conductor strip by introducing a dielectric slab into the conductor plane region of the groove guide antenna. The leakage property of the new antenna is carefully examined through calculations of an equivalent network, which is developed here with taking into account the coupling between different modes to guarantee the calculating accuracy. It has been found that the new leaky wave antenna is of larger leakage constant than that for the original groove guide antenna because of the introduction of the dielectric slab. Extensive numerical results of the leakage characteristics are given to establish useful guidelines for the design of the new type groove guide leaky wave antenna.     

The dominant mode in closed circular groove guide

The structure of closed circular groove guide is similar to that of open circular groove guide, but it can prevent energy from leaking out of the guide. In this paper, the dominant mode in closed circular groove guide is considered. The characteristic equation is derived and solved and the results are discussed.The Project Supported by National Natural Science Foundation of P. R. China and National Key Laboratory of Millimeter Waves Foundation of P. R. China     

Analysis of groove NRD waveguide bend using the coupled-mode theory

In this paper, the propagation characteristics of the dominant mode in GNRD guide bend are analysed employing the coupled-mode theory. The curves of bending loss vs. The groove depth or width, radius of curvature and frequency are given, which caused by the mode conversion of the operatingLSM ₁₁ ^x mode to the parasiticLSE ₁₁ ^x mode. It is found that the groove depth has a great influence upon the bending loss than the other parameters. According to the theoretical results, appropriate sizes of groove and radius of curvature should be chosen in designing a GNRD bend structure.     

The effect of tolerance on characteristic of circular groove guide

The variations in propagating characteristic of circular groove guide due to tolerance are analyzed by using eigen-weighted boundary integral equation method (EWBIEM). Theoretical analysis and experimental results show that as long as the tolerance of circular groove guide is not very large the variations in characteristic of circular groove guide are very small.The Project Supported by National Natural Science Foundation of P.R. China     

Circular Groove Guide Coupled with High-Q Cavity

The structure of circular groove guide coupled with high-Q cavity is studied. As a new type of millimeter wave component, it can be used for wavemeter and highly stabilized circular groove guide oscillator. The design and analysis of the novel structure are given in this paper.     

The wide band property of circular groove guide

According to the analyses of the moding properties of circular groove guide, the guide dimension for single mode operation is determined. Our results show that circular groove guide has the advantage of wide band.The Project Supported by National Natural Science Foundation of P.R. China and National Key Laboratory of Millimeter Waves Foundation of P. R. China     

Field Patterns in Asymmetrical Double Groove Guide by Finite Element Method

The electromagnetic power coupling in asymmetrical double-groove guide is analyzed by finite element method (FEM) in this paper. The electrical field patterns of the dominant mode and the first higher-order TE mode have been presented. The electromagnetic field of the dominant mode is distributed with a concentration of energy in the wide groove region, while the electromagnetic field of the first higher-order TE mode is distributed with a concentration of energy in the narrow groove region. The results in this paper have important values in design of groove guide power coupler for millimeter wave applications.     

Transmission characteristics of several kinds of closed groove waveguides for millimeter waves

An advantage of closed groove guide over open groove guide is attended. In this paper, the several kinds of closed groove guides including the trapezoidal-, elliptic- and parabolic-groove guides as new types of millimeter wave transmission lines are presented. Their dispersion and cut-off characteristics of the dominant mode are analysed and compared with ones of the closed V-and circular- groove guides by using the equivalent network method. The obtained results have important meaning in theoretical studies and actual applications of groove waveguides.