FD-Probing (Fourier transform)

QuickWave offers the FD-Probing post-processing that can be invoked for two types of objects and depending on that delivers separate results:

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for Point Source and Point Probe the FD-Probing post-processing calculates Fourier transforms of the terminal voltage and current, and therefore extracts embedding impedance and admittance

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for contours the FD-Probing post-processing calculates Fourier transforms of voltage and current along contours and also Fourier transforms of fields integrals along the contours

There are four main applications of the FD-Probing post-processing:

The FD-Probing results contain the following results: Fourier transform of current I through the lumped port and voltage U across the lumped port (amplitudes and phases), absolute value of embedding impedance (Z=U/I), phase of embedding impedance, absolute value of embedding admittance (Y=I/U), phase of embedding admittance, absolute value of reflection coefficient (calculated with respect to the lumped port resistance if its value is finite, and with respect to 50Ω if the resistance is zero or +INF), phase of reflection coefficient, real part of impedance, imaginary part of impedance, real part of admittance, imaginary part of admittance, inductance defined as L=Im(Z)/(2πf), capacitance defined as C=Im(Y)/(2πf), E-field at point Ep, H-field at point Hp.

The FD-Probing results in the case of field integration along an arbitrary path contain the following results:

The FD-Probing results in the case of field integration along an arbitrary path contain the following results:

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amplitude of voltage and phase of voltage for E-field integration contour

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amplitude of current and phase of current for H-field integration contour

The FD-Probing post-processing comes across such needs and enables extraction of currents and voltages by integrating H-fields along a virtual loop surrounding a conductor and E-fields along a virtual line connecting two conductors. At the end, the Fourier transform of these integrals is performed.

This information may be helpful in the analysis of quasi-TEM circuits for verifying the frequency range of their TEM behaviour. Also, lumped element models of parts of 3D structures can be extracted. Please note that for TEM lines, the integration of both electric and magnetic fields over specific contours can be also used for extracting the characteristic impedance of the transmission line, calculated as a ratio of the integration results.

See also online documentation about FD-Probing.