New variational principle in electromagnetics

Bodnar, D.; Paris, Demetrius Theodore

doi:10.1109/tap.1970.1139642

Cited by 28 publications

(8 citation statements)

References 6 publications

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“…9, we computed the aperture admittance of the WR-90 waveguide with an infinite flange and compared it with analytical and experimental results available in the literature [10][11][12]. Formulas (6), (7) agree well with analytical results by Bois [10], Bodnar [11], and Baudrand [12].…”

Section: Reflection Coefficient Of An Oewg With a Flangesupporting

confidence: 59%

“…Analytical approaches to the reflection coefficient or equivalently the aperture admittance of a rectangular waveguide radiating into air in the presence of an infinite flange have been studied by many researchers [9][10][11][12][13][14][15][16], where modal expansionmode matching and variational principles are among most frequentlyused techniques. These authors provide equations for the reflection coefficient or the aperture admittance of an OERW, where complicated calculations such as series summation and numerical integration are required.…”

Section: Introductionmentioning

confidence: 99%

“…The widely-used commercial electromagnetic softwares CST Microwave Studio (MWS) v.2009 and Ansoft HFSS v.11 are used for the numerical simulation. Proposed formulas, however, are no replacements for full-wave computational or rigorous analytical methods [9][10][11][12][13][14][15]. An approach similar to one presented in this paper can be applied to derive formulas for the reflection coefficient of an OERW radiating into a material half space.…”

Section: Introductionmentioning

confidence: 99%

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New Formula for the Reflection Coefficient of an Open-Ended Rectangular Waveguide With or Without an Infinite Flange

Kim¹,

Enkhbayar²,

Bang³

et al. 2010

PIER M

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Abstract-New formulas are presented for the reflection coefficient at the open end of a rectangular waveguide radiating into air including the effect of wall thickness or flange. Existing formulas require significant amount of numerical calculations and do not cover the practical range of waveguide dimensions.Reflection coefficients of open-ended standard waveguides are simulated using commercial electromagnetic software and curve-fitted to derive new formulas. Proposed formulas also include the effect of the broad-to-narrow wall aspect ratio. The accuracy of proposed formulas is compared with existing analytical, numerical and experimental results.

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Section: Reflection Coefficient Of An Oewg With a Flangesupporting

confidence: 59%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

New Formula for the Reflection Coefficient of an Open-Ended Rectangular Waveguide With or Without an Infinite Flange

Kim¹,

Enkhbayar²,

Bang³

et al. 2010

PIER M

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show abstract

“…Then, the measured S 11a_sample was converted to normalized admittance, Y/ Y o parameter by a formula: Y/Y o =( 1− S 11a_sample )/(1 + S 11a_sample ). The SOO calibration techniques were validated by comparing normalized admittance, Y/Y o with the literature data [15][16][17][18][19][20][21][22] as shown in Figure 14. The real part, Re(Y/Y o ), and the imaginary part, Im(Y/Y o ), of admittance results were found to be in good agreement with literature data over the operational range of frequencies.…”

Section: Short-offset-offset Short (Soo) Standard Calibrationsmentioning

confidence: 99%

Materials Characterization Using Microwave Waveguide System

You¹

2017

Microwave Systems and Applications

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This chapter reviews the application and characterization of material that uses the microwave waveguide systems. For macroscopic characterization, three properties of the material are often tested: complex permittivity, complex permeability and conductivity. Based on the experimental setup and sub-principle of measurements, microwave measurement techniques can be categorized into either resonant technique or nonresonant technique. In this chapter, calibration procedures for non-resonant technique are described.The aperture of open-ended coaxial waveguide has been calibrated using Open-Short-Load procedures. On the other hand, the apertures of rectangular waveguides have been calibrated by using Short-Offset-Offset Short procedures and Through-ReflectLine calibration kits. Besides, the extraction process of complex permittivity and complex permeability of the material which use the waveguide systems is discussed. For one-port measurement, direct and inverse solutions have been utilized to derive complex permittivity and complex permeability from measured reflection coefficient. For two-port measurement, in general, the material filled in the waveguide has been conventional practice to measure the reflection coefficient and the transmission coefficient by using NicholsonRoss-Weir (NRW) routines and convert these measurements to relative permittivity, ε r and relative permeability, μ r . In addition, this chapter also presents the calculation of dielectric properties based on the difference in the phase shifts for the measured transmission coefficients between the air and the material.

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“…These errors are primarily due to the exclusion of higher-order modes in the theoretical fonnulation. To remedy this problem several attempts have been made which incorporate the effect of higher-order modes in the derivations [1][2][3][14][15][16][17][18][19][20][21], …”

mentioning

confidence: 99%

A Multi-Mode Solution for Analysis of the Reflection Coefficient of Open-Ended Rectangular Waveguides Radiating into a Dielectric Infinite Half-Space

Bois

Benally

Zoughi

1998

Review of Progress in Quantitative Nondestructive Evaluation

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The open-ended rectangular waveguide probe is a powerful tool for characterizing the dielectric and reflection properties of various materials and structures [1][2][3][4][5][6][7][8][9][10][11]. In these applications the measurable parameter, r (i.e. the reflection coefficient), is used to determine the sought-for parameters. The said reflection coefficient is defmed as the ratio of the reflected electric field at the aperture of the waveguide to that of the incident electric field.In light of this, many studies have dealt with the radiation properties of the openended waveguide probe radiating into an infinite dielectric half-space. The original studies, using variational principles, approximate the field distribution at the aperture to that of the dominant propagating TE IO mode [12][13]. Although these derivations are reasonably accurate and computationally efficient for most practical cases, they lead to significant errors when attempting to re-calculate the dielectric properties of the infinite half-space from the measured rfor a certain range of dielectric properties and frequency of operation in the waveguide band [10]. These errors are primarily due to the exclusion of higher-order modes in the theoretical fonnulation. To remedy this problem several attempts have been made which incorporate the effect of higher-order modes in the derivations [1][2][3][14][15][16][17][18][19][20][21],

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New variational principle in electromagnetics

Cited by 28 publications

References 6 publications

New Formula for the Reflection Coefficient of an Open-Ended Rectangular Waveguide With or Without an Infinite Flange

New Formula for the Reflection Coefficient of an Open-Ended Rectangular Waveguide With or Without an Infinite Flange

Materials Characterization Using Microwave Waveguide System

A Multi-Mode Solution for Analysis of the Reflection Coefficient of Open-Ended Rectangular Waveguides Radiating into a Dielectric Infinite Half-Space

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