An Active Transmission Line Solution for Loss Characteristics of the Groove Guide

The analysis of loss characteristics for groove guide is one of the most practically important problems in millimeter wave system consisting of groove guide. In this paper, the calculation of the skin loss for the modes in the groove guide is ended to the solution of an active equivalent transmission line equation. The effectiveness and the reliability of the present method are verified by comparison between the present results and those given in the literature.     

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 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.     

Wave Propagation Along a Helical Step-Loaded Groove Waveguide

A new kind of helical groove structure, step-loaded groove waveguide is presented and analyzed in this paper. The dispersion equation of this structure is derived by means of a field-matching method. This equation may be reduced to the dispersion equation of helical ridge-loaded structure and rectangular one. In order to demonstrate the influence of the step on the dispersion properties, the comparison of the dispersion characteristics is made in these helical rectangular and modified rectangular groove structures. Form the analysis, it is shown that the step loading tends to reduce the dispersion of the helical groove circuit and the step-loaded structure has the weaker dispersion compared with the rectangular one or the ridge-loaded one. The effect of the step shape on the wave properties is also discussed under the deep groove case. The theoretical results explicitly indicate that the V-like step-loaded structure has the weakest dispersion in all step-loaded structures.     

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.     

Analysis of dispersion characteristics of groove guides with mode-matching method

Groove guide is widely recognized as one of the most promising millimeter wave transmission structures. In this paper, the mode-matching method is used to analyse the dispersion characteristics of single and asymmetrical double groove guides, and the unified formulae of Nth-order approximation dispersion equations are presented. Based on this analysis, a general program for calculating the dispersion characteristrics of single and asymmetrical double groove guides has been completed. Some comparisons between the results obtained by present method and published data show that very good agreement has been seen. The effectiveness and the reliability of the given formulae and program are thus verified.     

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.     

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     

Analysis of the mono-groove NRD waveguide and antenna

In this paper, an improved structure of symmetric groove nonradiative dielectric (GNRD) guide, the mono groove NRD (MGNRD) guide is presented, which keeps the similar performances of the symmetric groove structure, but is more easy to fabricate in millimeter waveband. The dispersion characteristics of the MGNRD is analysed using the transverse resonance method, then a MGNRD leaky-wave antenna is constructed, calculated and tested. The theoretical and experimental data are agreement with each other, and shows a attractive prospect for application.This article is supported by the State Natural Science Foundation of China.     

ANALYSIS OF ARBITRARILY TRAPEZOIDAL-GROOVE GUIDE WITH THE CONFORMAL MAPPING METHOD

The arbitrarily open trapezoidal-groove guide is analyzed with the conformal mapping technique. A new formula is given for the evaluation of one fundamental parameter associated with the technique. The relationship between the cut-off wavelength for the dominant mode and the geometry of the guide structure is studied; dispersion characteristic of the groove guide is also given. Some numerical results are shown to be in good agreement with both experimental data and the results of the finite element method (FEM). Moreover, it is testified that dispersion of the trapezoidal-groove guide is low. The obtained results are significant for the design and application of the open trapezoidal-groove guide for millimeter waves.     

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.     

The Analysis of Post-Mount in W-Band Circular Groove Guide

Finite-difference time-domain (FDTD) method is used to calculate the driving-point impedance of the circular groove guide diode mount. A simple way is proposed to approximate the curvilinear metal boundary of circular groove guide. Discrete equations are obtained from the Ampere's law and Faraday's law. Perfectly matched layer (PML) is applied on the open boundary of circular groove guide. At last program is made to obtain the field components. The driving-point impedance can be achieved from the ratio of the Fourier transform of the voltage and the Fourier transform of the current. The cutoff frequency and field pattern of the dominant mode are also obtained with well agreement with the theoretical results, this verifies the validity of the FDTD program.     

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.     

On the Main Mode of Trapezoidal-Groove Guide By Finite Element Method

In this paper, the propagation properties such as the dispersion characteristics, cut-off wavelength, guide wavelength and field distribution for the main mode of trapezoidal-groove guide are analysed by using the finite element method. The dispersion is very low, and the field distribution in a trapezoidal-groove guide is similar to that of rectangular one. The results have important values in design, manufacture, and application of groove guides.     

Analyzing Semicircular Groove Guide with the Conformal Mapping Technique

Semicircular groove guide is a kind of waveguide for millimeter waves. In this paper, a conformal mapping technique is used to analyze it. Several semicircular groove guides are calculated with the method. It is shown that their cutoff wavelength calculated by the method are very close to those calculated by the transverse resonance method.     

The Analysis of Radial Transmission-Line in W-Band Circular Groove Guide

In this paper, finite-difference time-domain (FDTD) method is used to calculate the driving-point impedance of radial transmission-line in circular groove guide. A simple way is used to approximate the curvilinear metal boundary of circular groove guide. And perfectly matched layer (PML) is applied on the open boundary of circular groove guide. Fine-grid is used to calculate the EM fields in the radial transmission-line in which we are interest. Discretized wave equation is used to update the tangential electric field on the boundary of coarse- and fine-grid. At last, the driving-point impedances related to different diameter of the radial transmission-line are obtained from the ratio of the Fourier transform of the voltage to the Fourier transform of the current.     

Effect of Dielectric Groove Profiles on Reflection Characteristics of Millimeter Wave Frequency Selective Surface

In this paper, the frequency selective reflection characteristics of dielectric periodic structures with arbitrary groove profiles are analyzed by a method which combines the multimode network theory with the rigorous mode matching procedure. Emphasis is placed on the discussion about the effect of the different groove profiles, such as rectangle, trapezoid, increasing cosine and triangle, on the reflection characteristics of the millimeter wave (MMW) frequency selective surface (FSS). Some useful guidelines for the design of the MMW dielectric FSS are thus suggested. Moreover, the physical explanation of the related wave phenomenon is given.