1,720,974 research outputs found
Analysis of Radiating Structure Input Impedance in Reverberation Chambers
No full textThis paper focuses on the study of the input impedance of radiating structures placed in a reverberation chamber, comparing it to what measured in an anechoic environment. The following emitters are considered, because usually responsible for radiated emissions in equipment under test (EUT): common mode current in a cable, differential mode current flowing into a closed circuit, and radiation from apertures. The analysis is performed via experimental measurements, by using a reverberation chamber and an anechoic corner. Differences in terms of input impedance have been observed in the case of common mode emissions and radiation from aperture in the EUT enclosure. Minor differences have been detected for the differential mode radiation
Uncertainty Analysis on the Reconstruction of the Radiated Field in a Multiple Monopole Source Stirred Reverberation Chamber
No full textIn this paper a statistical analysis on the measurement uncertainties related to the radiated emissions of an Equipment Under Test (EUT) is reported. The measurement environment is a Reverberation Chamber (RC), where the EUT is placed inside its working volume and the electric field is sampled close to the RC's metallic walls. From these measurements the free space emission of the EUT is reconstructed. The RC is equipped for the Multiple Monopole Source Stirring (MMSS) technique, which requires an array of monopole antennas placed onto the walls; therefore, in the present paper, the same antennas are used to sample the orthogonal component of the electric field radiated by the EUT. Two uncertainties mechanisms are analyzed: the position of the monopoles onto the walls and the direction of the monopole, that in the ideal scenario are perfectly orthogonal to the walls, but in a more realistic scenario, they could be oriented slightly in a different way
Theoretical Analysis of a Wall-Mounted Broadband Antenna for Source Stirred Reverberation Chambers
Full text linkThis paper is based on the analytical formulation of a method for predicting the electromagnetic field radiated by a wire antenna placed in a reverberation chamber. The antenna is discretized by a series of oblique segments. After verifying this assumption using full-wave numerical simulations, the proposed model is applied to a broadband antenna designed for a multiple antenna source stirred reverberation standard. The model can be used to analyze the performance of the chamber with respect to a number of indicators. This analysis has been extended to the entire frequency range in which the chamber has been experimentally characterized
Design of a Broadband Antenna for a Reverberation Chamber with Multiple Antenna Source Stirring
No full textThis paper presents the design of a broadband antenna to be used in a multiple antenna source stirring scenario. Usually, an array of monopole is placed onto the chamber's walls and the antennas are sequentially fed to perform the stirring action. But monopoles are intrinsically narrowband antennas: for this reason the use of a broadband antenna was investigated. The adopted structure is a helix antenna able to minimize the chamber volume reduction and to maximize the averaged power delivered to the chamber. Its performance was investigated by analyzing some typical RC performance indicators
Rician K Factor Tuning for 5G Channel Emulation in Different Typologies of Reverberation Chambers
No full textReverberation chambers usually exhibit low values of the Rician k factor; this means that the stirred component of the electromagnetic field is dominant with respect to the unstirred one. To increase this parameter in order to emulate propagation environments for 5G telecommunication systems, usually lossy elements are added into the chamber. In this way, the strength of the field inside the cavity decreases and more amplification of the signal is needed. This paper shows how to increase the Rician k factor by selecting a subset of electromagnetic configurations without the insertion of dissipative material. Successful results were obtained using different typologies of stirring techniques, multiple monopole source stirring, rotating paddles mechanical stirring, and oscillating wall stirring
Theoretical Radiated Emission Prediction of an Aperture Array by Reverberation Chamber Field Sampling
No full textThis paper reports the application of a theoretical model designed to predict the electromagnetic field radiated by a piece of equipment under test through an array of apertures on its metallic chassis. The simulated scenario is a reverberation chamber where the electric field is measured close to its walls. At this scope the multipole monopole source stirring technique is considered because of the presence of the antennas onto the chamber's walls. The results are successfully compared to the emissions in free space, and a wideband frequency analysis is performed. Finally, the effect of a random numeric noise on the module and on the phase of the electric field samples is analyzed
Emission Test Method for Source Stirred Reverberation Chambers With Scalar Measurements
Full text linkThis paper describes a novel method to reconstruct the radiated emission of a device under test placed in a reverberation chamber equipped with multiple monopole source stirring technique. The method is based on the measurement of the normal component of the electric field, collected close to the walls of the chamber by the monopole antennas. The main improvement from the previous formulation of the method is that the only knowledge of the amplitude of the electric field is sufficient to reconstruct, within a predictable range of uncertainty, the maximum level of the radiation of the device over all the directions at a given distance. The consequent advantage is that the method is immediately usable in a realistic scenario for emission tests, where an EMI receiver or a spectrum analyzer are used to measure the electric field and therefore only the amplitude of the field is retrieved
Flexible FDTD Simulation for the Wireless Earphone Exposure Evaluation
No full textThe electromagnetic field penetration into a human head is computed when a wireless earphone is dressed. The computation done by a home made FDTD code able to account for tissues permittivity and for a real feeding of the earphone antenna. We adopted a human head model developed on the Zubal Phantom downloaded from SourceForge. Permittivity values are assigned to each tissue accounting for the Cole-Cole frequency dependence
Rician K Factor Fluctuation in Reverberation Chambers
Full text linkReverberation chambers play a fundamental role in evaluating the efficacy of wireless communication systems by providing controlled environments for testing. One crucial aspect of this assessment is the manipulation of the Rician K factor within these chambers. The inherent challenge lies in the typically low values of the Rician K factor, necessitating intentional adjustments to replicate real-world communication scenarios accurately. This paper aims to expound upon the statistical analysis of the Rician K factor, focusing on the various measures undertaken to modulate this parameter. The experimentation involves a comprehensive examination of actions taken to tune the Rician K factor. One of the key strategies involves the strategic insertion of lossy elements within the reverberation chamber. These elements introduce intentional signal attenuation, impacting the Rician K factor and contributing to a more realistic simulation of wireless communication conditions. The paper delves into the intricacies of selecting and placing these lossy elements to achieve the desired level of signal degradation and, consequently, an appropriate Rician K factor. Furthermore, the investigation considers the positioning of these lossy elements within the reverberation chamber. The spatial distribution and arrangement of these elements can significantly influence the electromagnetic field characteristics, affecting the Rician K factor. In addition to the insertion and placement of lossy elements, the orientation of the receiver within the chamber emerges as another factor under analysis. The paper explores how variations in receiver orientation impact the statistics of the Rician K factor Keywords - mechanical stirring; reverberation chamber; Rician K factor; statistical analysis
Well-Stirred Condition Method applied to a Multiple Monopole Source Stirred Reverberation Chamber
No full textThis paper reports the application of the well-stirred condition method to a multiple monopole source stirred reverberation chamber. Measurements and theoretical simulations confirm the applicability of this method to the examined scenario
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