No abstract

No abstract

A concept of backward-wave bianisotropic composite medium matched to free space is suggested. It is based on the use of a uniaxial bianisotropic structure embedded into a matrix with negative effective permittivity. Since bianisotropy is easier to achieve in the optical range than artificial magnetism, this concept is prospective for optical backward-wave metamaterials. As an example of possible realizations, a microwave Ω-composite combined with a wire lattice is analytically studied.Design and studies of materials with negative electromagnetic parameters supporting backward waves is currently a very active field of research. The concept of backward waves is not new: It goes back to the beginning of the 19th century and is connected to the names of Lamb, Schuster, and Pocklington. In the middle of the 20th century, this concept was extended to waves in homogeneous materials and negative refraction effect was theoretically predicted (Mandelshtam, Sivukhin, Silin, Veselago). Detailed reviews on the current status and on the history of this research field can be found in e.g. [1][2][3][4][5][6][7].The main application for backward-wave materials is in sub-wavelength imaging devices ("perfect lens" [8]-[10]), but a full range of other possibilities is expected, especially for optical frequencies, if low-loss and matched slabs of backward-wave materials are realized [6,11]. The well-known design approach for the microwave range is based on the use of arrays of long thin metal conductors and split rings [12]. This approach has been extended to terahertz [13] and even infrared frequency range [14]. Realization of negative permeability with the use of split rings becomes very problematic at optical frequencies, and some alternative approaches have been proposed [18]- [21]. Considerable progress has been reported along this route, but the samples realized so far suffer from high losses and poor matching with free space [13,14]. There exist possibilities to realize backward waves also in anisotropic media [15,16] and in anisotropic waveguides [17], which do not necessarily require magnetic properties of materials, but are restricted to strongly anisotropic structures. In addition, difficulties to realize backwardwave samples matched to free space inhibit potential applications both in the microwave and in the optical regions.Majority of researchers focus on the design of magnetodielectrics, where the backward-wave regime is realized when both the permittivity ǫ and permeability µ have negative real parts. Following to paper [22], the bianisotropy is usually considered as a factor that one should avoid in the design of backward-wave materials, and effort is often concentrated on the design of symmetrical variants of split rings which minimizes magnetoelectric coupling [23]. However, backward waves can exist in more general linear media, namely in bianisotropic media (e.g., in chiral media [24]-[26]). It was recently demonstrated that in chiral media it is possible to improve the characteristics of backward-wave regime [26,...

Abstract-An alternative approach for assessing the conformity of electromagnetic interference measuring receivers with respect to the baseline CISPR 16-1-1 requirements is proposed. The method's core is based on the generation of digitally synthesized complex waveforms comprising multisine excitation signals and modulated pulses. The superposition of multiple narrowband reference signals populating the standard frequency bands allows for a single-stage evaluation of the receiver's voltage accuracy and frequency selectivity. Moreover, characterizing the response of the weighting detectors using modulated pulses is more repeatable and less restrictive than the conventional approach. This methodology significantly reduces the amount of time required to complete the verification of the receiver's baseline magnitudes, because time-domain measurements enable a broadband assessment while the typical calibration methodology follows the time-consuming narrow band frequency sweep scheme. Since the reference signals are generated using arbitrary waveform generators, they can be easily reproduced from a standard numerical vector. For different test receivers, the results of such assessment are presented in the 9 kHz-1 GHz frequency range. Finally, a discussion on the measurement uncertainty of this methodology for assessing measuring receivers is given.

Abstract-This paper presents an effective medium approach to calculate the attenuation and phase constants of modes in a 3D connected wire medium both below and above the plasma frequency. Physical and nonphysical modes in the structure are identified for all the important lattice directions. According to this, the medium behaves as an isotropic material in the vicinity of the plasma frequency. These results were compared with the numerical simulation and it was observed that the wave spreads below the plasma frequency along all the important lattice directions with the same attenuation constant. This implies isotropic behavior of the 3D wire lattice below the plasma frequency, and thus this medium can be considered as an isotropic negative permittivity medium.