In this paper, an efficient method for the numerical simulation of near-and far-field propagation of stochastic electromagnetic (EM) fields is presented. The method is based on the transformation of field correlation dyadics using Green's functions or the field transfer functions computed for deterministic fields. The method accounts for arbitrary correlations between the noise radiation sources and allows to compute the spatial distribution of the spectral energy density of noisy electromagnetic sources. The introduced methodology can be combined with available electromagnetic modeling tools. It is shown that the method of moments can be applied to solve noisy electromagnetic field problems by network methods applying correlation matrix techniques. Examples demonstrating the strong influence of the correlation between the sources on the spatial distribution of the radiated noise field are presented.Index Terms-Electromagnetic interference, near-field scanning, noisy electromagnetic fields, stochastic electromagnetic fields. 0018-9480

decisive drawbacks are (i) only a low to moderate level of scalability, (ii) restrictions for the size as well as the material of the substrate due to high-vacuum processes at elevated temperatures, iii) a lack of mechanical flexibility and iv) optical transparency.A few of these obstacles have been overcome with the emergence of novel materials such as carbon nanotubes (CNTs), graphene, [2] graphene oxide, [3] poly (3,4ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), [4] metal nanomeshes, [5] silver-coated polyester films (AgHT), [6] silver flakes, [7] silver nanoparticles, [8] copper oxide nanoparticles [9] as well as metal nanowires. [10,11] For the majority of these materials, scalable and high-yield synthesis protocols or fabrication techniques exist and these materials can potentially be deposited at almost arbitrary scale and under ambient conditions. Due to the cost-effectiveness, the ease-of-processing and the scalability, deposition methods such as inkjet printing, [12] direct laser writing, [13] spray coating [14] or screen printing [15] have become increasingly popular over the last years and raised academic and industrial interest.A high optical transparency of the deposited films is already a requirement for numerous antenna applications including solar cells, [16] sun shields on satellites, [17] radio-identification tags (RFIDs), [18][19][20][21] smart glasses, [22] bandstop filters to reduce the interference from wireless local area networks (WLANs) [23] as well as for energy harvesting. [24,25] Due to this broad application spectrum and the commercialization potential, notable technology companies including the so-called Big Techs, have recently filed several patents related to transparent conductive films and their use for antennas. [26][27][28] The conducting and transparent films presented in this work were made of a commercially available silver nanowire (AgNW)-based screen print paste. The use of screen printed AgNWs for antennas has already been reported in 2014 by Song et al. [29] However, in that work, the antenna films were fully opaque, which is a criterion for exclusion in many applications. In this work, as transparent electrode (TE) material, AgNWs were selected since this material is currently considered as the most promising alternative to the prevailing TE material, i.e., indium tin oxide (ITO), [30] with regard to the electro-optical performance as well as the chemical and the mechanical stability. [31] The antennas presented in this work show a highThe advent of mobile communication has made antennas omnipresent. Conventional methods of antenna manufacturing cannot address the growing demands for novel applications requiring transparent and flexible antennas. In this paper, transparent silver nanowire films are studied with respect to their highfrequency properties. Transparent silver nanowire (AgNW)-based antennas that are screen printed onto flexible polyethylene terephthalate (PET) substrate are reported. Transparent films with a low sheet resistance of 8.5 Ω sq −...

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Stochastic electromagnetic fields can be described by the auto-and cross correlation spectra of the electric and magnetic field values at pairs of points in space. In this work the characterization of noisy electromagnetic fields by sampling the field values in pairs of sampling points is discussed. Sampling of the electric or magnetic field values in all pairs of a set of sampling points yields the correlation matrix of the field samples. If the near-field in a surface of reference enclosing the stochastic field sources is sampled and characterized by its correlation matrix the field radiated in the space outside the surface of reference can be calculated and described by the field correlation spectra. Depending on the number of statistically independent field sources the eigenvalue decomposition of the correlation matrix yields a compact description of the measured EM noise field. I. INTRODUCTIONNumerical values of noise amplitudes cannot be specified for stochastic signals. For numerical modeling of noisy circuits one has to deal with energy and power spectra. Correlation matrix based methods have been developed for the numerical simulation of noisy linear circuits [1]- [4]. Stochastic electromagnetic fields can be described by the auto-and cross correlation spectra of the electric and magnetic field values at pairs of points in space. In this work the characterization of noisy electromagnetic fields by sampling the field values in pairs of sampling points is discussed. Sampling of the electric or magnetic field values in all pairs of a set of sampling points yields the correlation matrix of the field samples. If the nearfield in a surface of reference enclosing the stochastic field sources is sampled and characterized by its correlation matrix the field radiated in the space outside the surface of reference can be calculated and described by the field correlation spectra. Depending on the number of statistically independent field sources the eigenvalue decomposition of the correlation matrix yields a compact description of the measured EM noise field.According to the uniqueness theorem the field in a sourcefree region outside a volume V enclosing electromagnetic radiation sources is determined in a unique way, if the tangential component of either the electric field intensity or the magnetic field intensity is known on the boundary surface ∂V of the volume V [5]. Therefore based on either the tangential electric field or the tangential magnetic field sampled on the boundary ∂V of the volume V enclosing the field sources allows to compute the electromagnetic field in the region outside V .

Magnetic-resonant wireless power transfer (MRWPT) has been typically realized by using systems of coupled resonators. In this paper, we introduce a rigorous network modeling of the wireless channel and we introduce several viable alternatives for achieving efficient MRWPT. Ideally, the wireless channel should realize a 1:n transformer; we implement such transformer by using immittance inverters. Examples illustrate the proposed network modeling of the magnetic-resonant wireless power channel.