Hybrid-mode Analysis Research Articles

Advanced recursive modal integral technique for accurate hybrid mode characterization of symmetrical/asymmetrical multilayered uniaxial anisotropic planar structures

This paper introduces, for the first time, an extended modal integral technique for reliable characterization of multilayered symmetrical/asymmetrical planar structures built on arbitrary number of uniaxial electric/magnetic anisotropic layers. Based on a simple but efficient recursive algorithm devoted to composite substrates, the proposed hybrid mode analysis involves the Galerkin’s procedure combined with the formalism concept of mathematical operators to more conveniently formulate the boundary conditions. By properly selecting adequate trial functions, the technique was demonstrated through a close agreement between the obtained results and published data.

Computational analysis of cutoff wavenumbers in rectangular waveguides filled with left‐handed material and/or right‐handed material

This paper investigates the cutoff wavenumbers and their geometric and dielectric dependence in rectangular waveguides filled with left-handed material (LHM) and/or right-handed material (RHM). A rigorous hybrid mode analysis of these structures produces the dispersion equations and the formulations of cutoff wavenumbers for the first three modes. It is shown how the geometric and dielectric parameters may influence the cutoff wavenumbers of the waveguides filled with LHM and/or RHM. The graphs of cutoff wavenumbers over a range of geometric and dielectric parameters sufficiently wide to cover most requirements of design and application have been plotted. The cutoff wavenumbers of waveguides with LHM increase as the thicknesses or the absolute values of permittivity of LHM increase. It is noted that the variation rules of cutoff wavenumbers in waveguides with LHM show different changing tendencies compared with the waveguides with RHM.

Hybrid-mode analysis of circular waveguide with chiral dielectric lining for dispersion characteristics for potential application in broadbanding a gyro-traveling-wave tube

ABSTRACTA circular waveguide with chiral dielectric lining was analyzed for hybrid mode dispersion relation. In chiral dielectric lining region, the different radial propagation constants, and in the central free-space region only one radial propagation constant for the left- and right- circularly polarized waves were considered. A method was presented to obtain the hybrid-mode dispersion relation of the proposed structure using the field matching technique. A numerical computer code was developed to solve the hybrid-mode dispersion relation and the solutions were plotted to explore the dispersion characteristics and shaping with the change of material and geometry parameters of the structure. Further, the azimuthal electric field intensity was plotted against radial coordinate to explore the position of field maxima for placing the gyrating electron beam for the potential application of the structure in a gyro-traveling-wave tube. Thus, out of the two modes studied, EH01 and HE01, the later found suitable for the operation of a gyro-traveling-wave tube.

Microcavity electrodynamics of hybrid surface plasmon polariton modes in high-quality multilayer trench gratings

In common plasmonic structures, absorption and radiation losses are often mutually restricted and can seriously influence the device performance. The current study presents a compound structure composed of multilayer grating stripes and multilayer shallow trenches. A small depth was adopted for the trench configuration to exclude the extra bend loss. These two sections supported Fabry–Perot resonance and cavity modes, respectively, with hybrid modes formed through intercoupling. In addition, the total loss for the entire framework was clearly reduced due to the introduction of the trench geometry, indicating that both absorption and radiation losses were successfully taken into consideration in the compound structure. Significantly, such a low loss realized by the hybridization of surface plasmon polariton modes has rarely been seen before. Moreover, the debatable relationship between the total and partial quality factors was described for the first time based on a hybrid mode analysis to establish a new approach to investigate the different resonance modes. In the detailed calculation process, the relative electric field intensity was first adopted to stipulate the effective areas for the various modes, which is more reasonable than using the common definition that is based on a unit structure. The multilayer trench grating exhibited a relatively low loss without weakening energy localization, which is significant in the design of plasmonic devices.

Guided-Wave Properties of Mode-Selective Transmission Line

The so-called mode-selective transmission line or simply “MSTL” is studied theoretically and experimentally. This low-loss and low-dispersion transmission line operates with a frequency-dependent mode-switching behavior. This self-adaptive mode-selective guided-wave structure begins with the propagation of electromagnetic waves over the lower frequency range in the form of a quasi-TEM fundamental mode similar to the microstrip line case, then followed by a fundamental quasi-TE10 mode with reference to rectangular waveguide over the higher frequency region. To gain insight into the physical mechanism and fundamental features of this mode-selective transmission line, a detailed semi-analytical hybrid-mode analysis is developed through the application of a method of lines. This method allows accurate and effective modeling of MSTL guided-wave properties. Propagation characteristics of this proposed mode-agile structure in terms of dispersion, modal, and loss properties are examined, which leads to the establishment of some basic MSTL design guidelines. Numerical results confirm the expected mode conversion and low-loss behavior through the observation of field evolutions along the structure. For experimental verification, a set of MSTL prototypes are fabricated on two different substrates through dissimilar fabrication processes. Measurements are carried out from dc-to-500 GHz using a vector network analyzer. Excellent agreement between theoretical and experimental results is observed. It is confirmed that the low-dispersion and low-loss behavior of MSTL makes it an outstanding integrated waveguide in support of high-performance super-broadband signal transmission and/or ultra-fast pulse propagation in a fully-integrated platform.

ANFIS MODELS FOR SYNTHESIS OF OPEN SUPPORTED COPLANAR WAVEGUIDES

Simple and accurate models based on adaptive-network-based fuzzy inference system (ANFIS) to compute the physical dimensions of open supported coplanar waveguides are presented. The ANFIS is a class of adaptive networks which are functionally equivalent to fuzzy inference systems. Four optimization algorithms, hybrid learning, simulated annealing, least-squares, and genetic, are used to determine optimally the design parameters of the ANFIS. When the per- formances of ANFIS models are compared with each other, the best results are obtained from the ANFIS models trained by the hybrid learning algorithm. The results of ANFIS are compared with the results of the conformal mapping tech- nique, the rigorous spectral-domain hybrid mode analysis, the improved spectral domain approach, the synthesis formulas, a full-wave electromagnetic simulator IE3D, and experimental works realized in this study.

A New Measurement System for the Perpendicular Complex Permittivity to DUT Sheet by Stripline Simulation

The relative dielectric constant ε <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</i> is calculated by quasi-static and frequency-dependent hybrid-mode analysis of two layers of dielectric materials (a sample material and a resonator base material) after measuring the rate of change of the resonating frequency of a sheet material under test sandwiched between a sheet metal and a calibrated stripline resonator. This method corrects the fringing effect of the resonator by using two resonators that have slightly different resonating frequencies. In the present study, tan δ is calculated by balancing the conductor loss. The features of this method are as follows. 1) Measurement of ε <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</i> and tan δ is accurate. 2) Measurement can occur at several frequencies simultaneously. 3) Measurement can be made of ε <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</i> and tan δ in the <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i> direction perpendicular to the sheet material, e.g., a printed circuit board. 4) A metal pattern is not required. Only the sheet material under test is necessary. 5) Measurement provides accurate data since there is no radiation loss. This method is useful for measurement in the 0.5-14-GHz range, calculated at multiple frequencies. Fully automatic calculation can be achieved by computer analysis through connection to a network analyzer.

Quasi-static and hybrid-mode analysis of asymmetric coupled cylindrical striplines

Quasi-static and the frequency-dependent hybrid-mode analyses are presented for the general structure of coupled cylindrical striplines. Stationary expressions are derived for all elements of capacitance and inductance matrices which describe the quasi-static characteristics of the dominant C - and π-modes of asymmetric coupled cylindrical striplines. The hybrid-mode analysis is also developed to afford the frequency dependency of the phase constants as well as characteristic impedances. The characteristic impedances of asymmetric coupled striplines are evaluated first by using the appropriate definition based on the variational scheme. A very accurate numerical method is presented in incorporating the tight coupling between strip conductors and the edge singularities of the fields near the conductor edge properly. The frequency-dependent characteristics ensure consistency with the corresponding quasi-static solutions in lower frequencies, and the numerical results reveal the notable characteristics of the asymmetric coupled cylindrical striplines for the tight-coupling as well as the extremely weak-coupling cases.

F122002 ハイブリッドロケットの概念設計検討法と非劣解データのモード解析法出([F12200](設計工学・システム部門企画),多目的最適化は設計につかえるか?)

F122002 ハイブリッドロケットの概念設計検討法と非劣解データのモード解析法出([F12200](設計工学・システム部門企画),多目的最適化は設計につかえるか?)

ANALYSIS OF PERIODICALLY LOADED SUSPENDED SUBSTRATE STRUCTURES IN MILLIMETER WAVE

Abstract—This paper presents a comprehensive study on the hybrid mode analysis of a periodic structure in a Suspended Microstrip and Broadside-coupled Suspended Stripline. The analysis has been use of Floquet’s theorem in special harmonics to express the field equations in various sub regions of the periodic loaded suspended substrate. Their characteristic equation is derived, using the Galerkin’s procedure. The unknown electric field distribution in the substrate region, corresponding to one unit cell of the periodic structure is specified in terms of suitable basis functions. The characteristic of slow wave properties, resonance behavior and the passband-stopband characteristics are at the millimeter wave frequencies as a various structural parameters are presented.

Accurate hybrid mode analysis of hollow optical fibers

The dispersion relation equation of hybrid modes in hollow optical fiber is derived in the closed form by modeling the fiber in a three-layered structure and by rigorous hybrid mode analysis. The effective refractive indices of hybrid modes as a function of wavelength are accurately calculated. Modal characteristics and transverse field distributions of hollow optical fiber are precisely analyzed by use of the derived hybrid mode dispersion relation equation and the compact 2-D finite difference time domain method. In addition, the effects of the fiber dimension on propagating properties are presented. The number of hybrid modes that can exist in hollow optical fiber is calculated as a function of fiber dimension. We believe that this rigorous analysis is very accurate and provides precise computing methods to design and characterize hollow optical fiber based optical devices.

Full-wave analysis of coupled strip-slot guiding structures

In this paper, the coupled strip-slot lines are modeled using hybrid mode analysis. Standard spectral-domain analysis is employed to solve the eigenvalue problem in multilayered media and a novel formulation is proposed to obtain strip and slot modal impedances. Comparisons with available published data are presented. The model is used to obtain scattering parameters of a bandpass filter with a novel topology. These scattering parameters are then compared with those obtained using rigorous Sonnet simulations, thereby confirming the reliability of the model.

Hybrid mode analysis of microstrip lines by the method of lines with pseudospectral discretization

AbstractIn this paper, the method of lines (MoLs), which has been proved to be very efficient for calculating the characteristics of one‐dimensional and two‐dimensional planar microwave structures, is extended to nonequidistant discretization with pseudospectral technique. This pseudospectral MoLs is developed by combining pseudospectral technique and the MoLs, so that its solution is not only analytical along line direction, but also maintains high accuracy in discrete direction. A pseudospectral‐based discretization strategy, distribution of collocation nodes, global power series interpolation of differential quadrature, second‐order difference matrix, and decoupling of coupled ordinary differential equations are discussed in detail. The convergence behaviors are provided for line discretization, based on both the pseudospectral strategy and the second‐order finite difference (FD), respectively. The calculated results are compared with those published in the previous literature and our numerical results show that accuracy is improved with reduced computational effort for the analysis of microstrip lines. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 224–227, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10563

Novel beam-control techniques using dielectric-image-line-fed microstrip patch-antenna arrays for millimeter-wave applications

This paper reports novel beam-control methods which have the potential of low cost and simplicity. The beam direction of the antenna array is controlled by changing the distance between the perturbed dielectric image line (DIL) and a movable reflector plate. A rigorous hybrid-mode theoretical analysis is developed for calculating the dispersion of propagation constants in DILs without or with the movable reflector plate and, then, for designing beam-control patch-antenna arrays. Experimental results of scanning angles agree well with theoretical predictions at Ka-band frequencies.

New tunable phase shifters using perturbed dielectric image lines

This paper presents new tunable phase shifters using perturbed dielectric image lines (DILs). The propagation constant in the DIL was perturbed by a movable metal reflector plate installed in parallel with the ground plane of the DII. The phase shift was thus controlled and adjusted by varying the perturbation spacing between the DIL and movable reflector plate at a given operating frequency. A rigorous hybrid-mode analysis was used for calculating the dispersion of propagation constants in the perturbed DII, and then for designing tunable phase shifters. Ka-band tunable phase shifters have been designed, fabricated, and tested. Measurement results agree well with theoretical predictions. The device is especially useful for millimeter-wave applications where traditional phase shifters are lossy.

Analysis of hybrid modes in channel multilayer optical waveguides with the compact 2-D FDTD method

In this article, a full-wave numerical approach based on the compact 2-D finite-difference time-domain (FDTD) method is used for the analysis of hybrid modes of channel multilayer and multiple quantum well (MQW) waveguides. Numerical results in terms of field distributions and dispersion characteristics as a function of number of layers are given, and they are compared with available results obtained by the vector finite-element method. In addition, by comparing the field distributions of the hybrid mode and the scalar mode, it is found that to closely model the natural property of the channel multilayer and MQW waveguide systems, an analysis of the hybrid modes is necessary. © 1997 John Wiley & Sons, Inc. Microwave Opt Technol Lett 15: 398–403, 1997.

A Wiener-Hopf-type analysis of uniaxial substrate-superstrate microstrip structures

A Wiener-Hopf-type technique in conjunction with the hybrid-mode analysis and a space-domain Fourier transform pair was employed for the solution of the canonical problem of a TEM wave obliquely incident upon the edge and defined by a semi-infinite plate conductor lying at the interface of two uniaxial dielectrics, forming an otherwise grounded double-layer geometry. The single-cover layer and double-layer surface-wave modes' characteristic equations are examined and their cutoff conditions, along with safe conditions avoiding longitudinal-section magnetic (LSM) modes are given. The scattered field components and the TEM-wave reflection coefficient are given analytically in the form of Sommerfeld-type integrals. A thin layers approximation and a numerical integration scheme were adopted for the evaluation of the reflection coefficient. Its expression can be directly used for the analysis of wide microstrip lines and patch antennas printed in a substrate/superstrate geometry. The whole analysis gives a clear physical insight into the problem. Furthermore, a twofold theoretical verification was adopted by either forcing the absence of the superstrate or considering both layers to be isotropic. Numerical parametric Investigations show the effects of either the presence of the superstrate or both layers' dielectric anisotropy.

Hybrid-mode analysis of multilayered and multiconductor transmission lines

Hybrid-mode propagation properties of multilayered and multiconductor transmission lines are studied by using an efficient vector finite element method (FEM) with high-order hybrid edge/nodal triangular elements, which can give frequency-dependent propagation constants directly. Characteristic impedances are also calculated from the FEM field solutions employing a reciprocity-related definition and taking the modal orthogonality into account. The numerical results of a coupled microstrip line are compared with those of the boundary integral equation technique, and good agreement is obtained. Also, a dual-plane triple microstrip line is analyzed. The approach is found to be very general and able to simultaneously handle different thicknesses and widths of strip conductors. The flexibility of the approach is also shown by including anisotropy in the dielectric substrates of such lines.

Characterization of off-slot discontinuity in unilateral fin line

A new type of fin line discontinuity, which consists of a rectangular conducting strip placed transversely on the back side of the air dielectric interface containing the slot, is characterized in this work. Modeling of the fin line cavity containing the discontinuity is carried out using hybrid mode analysis, and then the transverse resonance technique is used to extract equivalent circuit parameters of the discontinuity. Suitable sets of basis functions are chosen for accurately representing the field in the slot and the current on the strip. Calculated results are compared with the measured results for a sample discontinuity to validate the choice of the basis functions.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Method of lines for analysis of waveguidestructures with multidiscontinuities

An efficient full-wave analysis, based on the method of lines, is performed on waveguides with multidiscontinuities. Three-dimensional hybrid mode analysis is used. The spectrum of the reflection coefficient for a periodic structure is provided as an example and is in good agreement with published results. Compared to other methods, the algorithm is stable in numerical computation for a large number of discontinuities.