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Powerlines can provide an economical medium for high-speed communications; however, the low-voltage electrical network is an unfriendly environment with interferences, noise, attenuation, and multi-path reflections. This paper presents a reliable multi-step procedure for designing an optimal broadband impedance-matching circuit providing gain equalization and mitigation of the effects of low-impedance loads on modern wide-band power line communications. Special attention is given to the application of such devices on board of luxury yachts, where the use of power line communications could dramatically reduce weights and costs. Results carried out on the network of a real yacht confirm the efficiency of the proposed approach.

The evaluation of the shielding effectiveness of metallic enclosures with apertures containing metallic objects and excited by arbitrary sources is the main topic of this work. The shielding effectiveness is computed through an integral formulation based on the Method of Moments which makes use of a fast computation of the enclosure Green functions. Absorbing artificial materials are also designed and proposed to damp the resonant fields excited inside the enclosure in order to improve the shielding performance.

The low-voltage powerline communication (PLC) field constitutes today a hot open research area. Powerlines, that often already exist to support energy distribution, can provide an economical broadband medium for high-speed reliable communication traffic, not only for equipment monitoring, protection, and control purposes, but especially today for supporting the smart home technology. However, despite several attractions, the low-voltage electrical network provides an unfriendly environment for data communications. Besides interferences, noise, attenuation, and multi-path reflections, the extremes as well as the unpredictability of the access impedance are limiting factors in the performance of PLCs. This paper presents a preliminary study about a possible methodology of designing an optimal broadband impedance matching circuit (BIM) for providing gain equalization and mitigation of the effects of low-impedance loads on the PLC modem in a wide frequency range. The design is achieved in successive steps by means of the Vector Fitting method, rational parametric approximation of the driving impedance and nonlinear optimization through a novel Meta Particle Swarm Optimization (MPSO).

Performance of artificial planar screens composed of small magnetic elements are investigated through equivalent circuit models and a full-wave approach involving a periodic method-of-moments formulation. The conventional split-ring resonator screen is first studied and next the geometry of the single inclusion is modified in order to reduce the operating frequency of the screen. It is shown how the proposed spiral-resonator screen can operate in the VHF band and that a careful numerical analysis needs to be carried out to accurately predict the selective properties of the screen. Different commercial full-wave software are also used and their limits in the modeling of such microstructured materials are pointed out.

The effects of conducting loads on the shielding effectiveness of rectangular metallic enclosures is investigated through an efficient formulation based on the method of moments. As expected, the analysis shows that the classical shielding effectiveness is a very tricky figure of merit which is seriously affected by the possible presence of loads inside the enclosure, especially in the frequency range above the first resonant frequency of the enclosure. Comparisons with rigorous full-wave results obtained through commercial software confirm the validity of the proposed technique and its high efficiency.