Surface Impedance Boundary Conditions

Yuferev, S.; Ida, Nathan

doi:10.1201/9781420044904

Cited by 63 publications

(93 citation statements)

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“…3. The conductor plates forming the resonator are represented by an impedance boundary condition, with the electric and magnetic fields excluded from the interior of the conductors [18, p 33], [19,20]. This type of boundary condition constrains mutually perpendicular components of the magnetic and electric fields in the boundary to be proportional, with the ratio given by the surface impedance…”

Section: Theory and Simulationmentioning

confidence: 99%

An optimised detector for in-situ high-resolution NMR in microfluidic devices

Finch

Yılmaz

Utz

2016

Journal of Magnetic Resonance

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Integration of high-resolution nuclear magnetic resonance (NMR) spectroscopy with microfluidic lab-on-a-chip devices is challenging due to limited sensitivity and line broadening caused by magnetic susceptibility inhomogeneities. We present a novel double-stripline NMR probe head that accommodates planar microfluidic devices, and obtains the NMR spectrum from a rectangular sample chamber on the chip with a volume of 2 l. Finite element analysis is used to jointly optimise the detector and sample volume geometry for sensitivity and RF homogeneity. A prototype of the optimised design has been built, and its properties have been characterised experimentally. The performance in terms of sensitivity and RF homogeneity closely agrees with the numerical predictions. The system reaches a mass limit of detection of 1.57 nMol p s, comparing very favourably with other micro-NMR systems. The spectral resolution of this chipGprobe system is better than 1.75 Hz at a magnetic field of 7 T, with excellent line shape.

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Section: Theory and Simulationmentioning

confidence: 99%

An optimised detector for in-situ high-resolution NMR in microfluidic devices

Finch

Yılmaz

Utz

2016

Journal of Magnetic Resonance

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“…can be easily obtained starting with the configuration of the strand immersed in a uniform longitudinal magnetic field H 0 z (r i ) because the field is not distorted by the induced currents in the conductor. Additionally, considering the azimuthal electric field inside the strand with a dependence shown in (22) associated with a surface current similar to (31), together with the fact that the magnetic field vanishes inside the conductor, it is possible to define the so called impedance boundary condition [48][49][50] establishing the relationship between the tangential magnetic and electric field in the surface of the strand. In this case, it should be noted that both the longitudinal electric field and the azimuthal electric field are tangential to the surface, thus:…”

Section: Low-and High-frequency Analysismentioning

confidence: 99%

Tm-Te Decomposition of Power Losses in Multi-Stranded Litz-Wires Used in Electronic Devices

Carretero¹,

Acero²,

Alonso³

2012

PIER

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Abstract-Efficiency often constitutes the main goal in the design of a power system because the minimization of power losses in the magnetic components implies better and safer working conditions. The primary source of losses in a magnetic power component is usually associated with the current driven by the wire, which ranges from low to medium frequencies. New power system tendencies involve increasing working frequencies in order to reduce the size of devices, thus reducing costs. However, optimal design procedures involve increasingly complex solutions for improving system performance. For instance, using litz-type multi-stranded wires which have an internal structure to uniformly share the current between electrically equivalent strands, reducing the total power losses in the windings. The power losses in multi-stranded wires are generally classified into conduction losses and proximity losses due to currents induced by a magnetic field external to the strand. Both sources of loss have usually been analyzed independently, assuming certain conditions in order to simplify the derivation of expressions for calculating the correct values. In this paper, a unified analysis is performed given that both power losses are originated by the electromagnetic fields arising from external sources where the wire is immersed applying the decomposition into transversal magnetic (TM) and transversal electric (TE) components. The classical power losses, the so called conduction and proximity losses, can be calculated considering the TM modes under certain conditions. In addition, a new proximity loss contribution emerges from the TE modes under similar conditions.

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“…It shall be underlined here that neither homogeneity, nor linearity of the electromagnetic parameters of the areas, provides the necessary assumption while applying the condition (1) [3]. Nonetheless, dependence (3) does not hold for nonlinear media and the local Z c magnitude should be then determined numerically.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4][5][6][7], more extensive references on this subject can be found in [3]). SIBC are to be applied to systems where skin effect occurs.…”

Section: Introductionmentioning

confidence: 99%

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