Modal analysis of the 'gap effect' in waveguide dielectric measurements

Wilson, Simeon

doi:10.1109/22.3581

Cited by 30 publications

(17 citation statements)

References 5 publications

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“…The air gap can form defects, which may generate localized modes in EBG and destroy the homogeneous, leading to inaccurate test results. Wilson et al [19] pointed out that filling the air gap with conducting paste can nearly alleviate the effect caused by the air gap. The air gaps in this work were filled with room temperature silver paste and the smooth S 21 j j spectrums were obtained as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

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Fabrication of three-dimensional electromagnetic band-gap structure with high-K dielectric ceramics by rapid-prototyping

Dai

Wang

et al. 2010

J Electroceram

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Three-Dimensional diamond structure electromagnetic band-gap (EBG) structures containing high-K dielectric ceramic Bi(Nb 0.992 V 0.008 )O 4 (BVN) fabricated by rapidprototyping (RP) technique were investigated. The simulations based on finite element method (FEM) were employed to model the band diagram. The influences of structure dimensions, aspect ratio and permittivity contrast on the band gap width were studied. The optimal band gap width EBGs were fabricated and investigated experimentally. EBG structures composed of epoxy resin diamond lattice and inversediamond lattice made of high-K BVN ceramic with silica gel were fabricated by RP method. The transmission characteristics of the EBG structures were measured by transmission/ reflection (T/R) methods with a vector network analyzer. Obvious wide band-gaps of two EBGs with different lattice parameters were observed in the curve of transmission characteristics, which agreed well with the simulation results.

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Section: Resultsmentioning

confidence: 99%

“…For T/R methods using the rectangular waveguide, the air gap, caused by imperfect match of the sample and the waveguide, is a serious uncertainty exciter [19]. The effect of air gap along the height is not as serious as that along the width since the excited TE 10 mode has a zero field at the short walls [17].…”

Section: Resultsmentioning

confidence: 99%

Fabrication of three-dimensional electromagnetic band-gap structure with high-K dielectric ceramics by rapid-prototyping

Dai

Wang

et al. 2010

J Electroceram

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“…Wilson [29] and Champlin [9] have analyzed the effect of an air gap on calculation of complex permittivity from transmission and reflection measurements. Wilson, using Wexler's formulation with a material slab discontinuity, successfully derived field expansions in the empty and PFW regions.…”

Section: Other Methodsmentioning

confidence: 99%

“…However, each higher order mode transmits or stores a finite amount of complex power that does not propagate to the 2 receiving sensor inside the network analyzer. Therefore, characterization using the NRW algorithm with the standard reflection (S 11 , S 22 ) and transmission (S 21 , S 12 ) scattering (S) parameters yields inaccurate results [17,21,29]. In addition, the reflection measurements are extremely sensitive to the axial placement of the sample in the waveguide.…”

Section: Problem Statementmentioning

confidence: 99%

Material Characterization Improvement in High Temperature Rectangular Waveguide Measurements

Buschelman¹,

Havrilla²,

Terzuoli³

et al. 2007

2007 International Conference on Electromagnetics in Advanced Applications

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This research presents a method using modal analysis by which electromagnetic characterization of materials in a partially filled rectangular waveguide, having a single top air gap, can be accurately performed. Thermal expansion of waveguides commonly occurs during high-temperature measurements, resulting in air gaps between the sample and waveguide walls. Higher order modes are excited by the discontinuous geometry, which are not accounted for in most closed form extraction algorithms. A correction must be applied that considers the complex power transmitted and stored by higher-order modes, not merely the dominant mode. Characterization independent of sample distance from the calibration plane is also presented.Expanding upon previous analysis of partially filled rectangular waveguides, a modal solution for a single air gap between the top of the material sample and the waveguide wall is developed. The analysis is performed on samples of dielectric to verify the method, and further tests are performed on magnetic shielding material.Boundary conditions between the empty and partially filled regions are formulated so it is only necessary to explicitly satisfy two of the existing three field components, the third being linearly dependent.Calculation of the complex permittivity and permeability of magnetic shielding material, within 10% of the true value, was achieved by using less than 20 modes. AcknowledgementsTremendous thanks go out to several people: My wonderful wife who always loved me and tried her best to keep me on track through these 18 months -you'll have many more chances in the future. To my son -you're so wonderful! How hard it was for me to leave the house for work when I wanted to spend time with you! Thank you for being so well behaved.To Dr. Havrilla, my advisor and best professor, who put up with a lot of my procrastination, but was (and is) always patient with me, and made me realize the importance of thinking physically and caring about details. Thanks for the neverending encouragement. The support of Dr. Crittenden was invaluable, and I owe a large part of this work to his guidance.

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“…will be excited at planes Z = 0 and Z = 1. Wexler [4] and Wilson [5] introduced a general method for solving waveguide discontinuity problems. Filled and unfilled portions of the waveguide are described by different sets of orthogonal modes.…”

Section: (2)mentioning

confidence: 99%

Complex permittivity and permeability measurements for high‐loss material in a waveguide

Cao

Yang

1995

Micro & Optical Tech Letters

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Modal analysis of the 'gap effect' in waveguide dielectric measurements

Cited by 30 publications

References 5 publications

Fabrication of three-dimensional electromagnetic band-gap structure with high-K dielectric ceramics by rapid-prototyping

Fabrication of three-dimensional electromagnetic band-gap structure with high-K dielectric ceramics by rapid-prototyping

Material Characterization Improvement in High Temperature Rectangular Waveguide Measurements

Complex permittivity and permeability measurements for high‐loss material in a waveguide

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