Guntars Balodis

Case Shielding Efficiency, High Frequency Technology

We have presented the comparison of different electromagnetic (EM) shielding case vent shapes (different shape, but same surface) and estimate EM shielding efficiency for one mode E wave. EM shield is the integral part of the effective functioning devices. By changing type of the shape vent, it is possible to minimize EM impact. It is offered to value the shielding efficiency, by using scattering S matrix in analysis. Ill. 15, bibl. 8 (summaries in English, Russian and Lithuanian).

Modified estimation of shielding efficiency for hole

For reduction of the impact of electromagnetic field on parameters of electronic equipment, shielding in many different shapes and qualities is used. The quality of the shielding is dependent on size, shape and amount of openings in the body of the shield. In electromagnetic immunity and emission tests it is very difficult to predict the shielding efficiency from theory of refraction, reflection and diffraction due to the very complicated shape and material mix in the design configuration of multilayer PCB, supports, covers and screens. For this reason in order to build up and make calculations of scattering matrix parameters as the estimation of the shielding efficiency in the given frequency range we propose to use the drawn 3D electromagnetic model.

Performance estimation for MIMO channel

In this paper we present the performance estimation for mobile environment wideband radio channel based on multiple antenna system. Wireless communications systems equipped with multiple antennas at both the transmitter and receiver have been widely stated as an important technology to improve performance. These so-called multiple-input multiple-output (MIMO) systems can increase diversity to reduce performance degradation due to the fading phenomenon in wireless channels. Using statistical signal processing approach Rayleigh, Rician and Nakagami fading scenarios are analyzed. Obtained results show slightly better performance for mean received power in Nakagami environment compared to Rician broadband radio channel in the weak interference conditions