Near-Field Scanning and Propagation of Correlated Low-Frequency Radiated Emissions

Abstract

Abstract-Electromagnetic radiation from complex printed circuit boards can occur over a broad frequency bandwidth, ranging from hundreds of MHz to tens of GHz. This is becoming a critical issue for assessment of EMC and interoperability as electronic components become more and more integrated. We use emissions from an enclosure with a single-slot aperture and equipped with operating electronics to exemplify and model such sources. Spatial correlation functions obtained from two-probe measurements are used both to characterise the source and to propagate the emissions. We examine emissions in the submicrowave frequency range, where evanescent decay dominates the measured correlation function at the distances measured. We find that an approximate, diffusion-like propagator describes the measured emissions well. A phase-space approach based on Wigner functions is exploited to develop this approximation and to provide enhanced understanding of the emissions.

Comparison of Microstrip Patch Antennas Operated on 2.45GHZ

“…Material of dielectric substrate is from Rogers Company denote as RO4350 with smaller value of dielectric constant in comparison with standard PCB (Printed Circuit Board) material FR04 [4][5][6][7]. connect two conduct layer placed on both sides of substrate [8][9][10]. The main parameter which represents impedance matching and resonance on operating frequency is S 1,1 parameter.…”

Stochastic electromagnetic field propagation— measurement and modelling

“…Starting with the source correlation in momentum space, calculated from boundary data, propagation along the normal direction to the source is described by the propagator using the notation of ( 2.9 ) and where and p = | p |. The transport equation for the WT can then found by inserting ( 2.17 ) into ( 2.8 ) with a kernel given by the dyadic operator where 1 is the unit dyad, from which ( 2.21 ) can be written as [ 33 ] where * x denotes the convolution operation acting only on the spatial variable x . It has been shown in [ 28 , 29 ] that can be simplified through a ray-based approximation for spatial variations in the source correlation that are on a scale that is larger than the wavelength.…”

“…Even better agreement is found for the energy densities reported in figure 2 d , e , both accurately reproducing the measured intensity in figure 2 f . To have a better insight into the accuracy of the approximated WF method, we use the exact MoM method as a reference (where an exact WF propagator has been used in previous work [ 28 , 33 ]). In particular, the differences between both the propagated energy densities and the measured data have been calculated for the example in figure 2 , in order to quantify the relative errors of the two methods with respect to measurements.…”

“…However, the MoM is computationally more intensive than the approximated WF and does not transparently provide information on space-angular properties of emissions as the WF does. We stress that exact formulations of the WF method, based on the full kernel defined in ( 2.20 ), are available [ 28 , 33 ] as an alternative to MoM, but these would be similarly computationally more intensive. The WF method propagates input data with the level of efficiency of a double Fourier transform.…”

Analysis of Nonstationary Emissions for Efficient Characterization of Stochastic EM Fields

“…This algorithm is used to propagate fieldfield correlation functions from the near-field scanning measurement. The field-field correlation function can be provided through measurement by one-probe measurements [7] and two-probe measurements [3], [8]. For the measurement of complex devices, it is more appropriate to do a two-probe measurement in the time domain because of the lack of phase/time reference.…”