Abstract This paper presents an eyebolt structural fault detection system, based on the analysis of multiple electromagnetic parameters through a random forest classifier trained by both measurements and high-fidelity simulated signals. The proposed methodology is completely noninvasive and does not require the disassembly of the electrical infrastructure, allowing the live-line working. The obtained results show that the proposed multi-parameter strategy achieves high accuracy and increases the system’s capability of detecting faults, improving the efficiency of the operator’s preventive maintenance routines and, consequently, increasing the reliability of the power supply and energy distribution systems. system highfidelity fidelity signals infrastructure liveline live line working multiparameter multi parameter systems s faults operators operator consequently

Abstract This paper presents the implementation of a 3-bit microstrip fractal-based phase shifter operating in the 430 MHz to 470 MHz frequency range. The fractal structure is used to confine different delay line lengths in the same area due to the space-filling properties of the used Hilbert fractal curve. The proposed design has three bits corresponding to 45, 90, and 180 degrees phase changes selected according to the switching circuit based on a Double Pole Double Throw (DPDT) switch implemented with PIN diodes. Comparisons between simulated and measured results are shown according to the chosen degree of use of PIN diodes.

Abstract The structural condition of the cable-stayed towers anchorage on power transmission lines requires constant monitoring. Maintenance routines must be able to identify faulty anchor rods and substitute them to avoid tower collapses and power delivery interruptions. Modern statistical diagnostic systems based on machine learning requires the generation of several distinct rod sample signals to be trained, which is a time-consuming process in typical electromagnetic solvers. Aiming to generate samples in a feasible time span, this paper presents a modeling strategy based on the cascade analysis of the transmission line composed by the anchor and the reference rods, interconnected by a dedicated high-frequency connector. Each distinct transmission line part is modeled by a quadrupole as a partial ABCD matrix. The complete response for each experimental setup is obtained from the cascaded-multiplying of the partial matrices. The proposed modeling proved to be accurate and provides a faster way to obtain the S-parameters from distinct faulty rods if compared to the traditional methodologies using electromagnetic tools.

Abstract This paper presents a compact and planar reconfigurable filtenna for application in Wireless systems. The filtenna is composed of a UWB circular antenna and a filter with two trapezoidal resonators. The filter is integrated on the antenna feed line and has a band-pass frequency response. The filtenna frequency response reconfiguration is achieved by changing the capacitance of a varactor diode, placed between filter resonators; the capacitance varies continuously from 1.32 pF to 4.09 pF according to an applied bias voltage. The varactor capacitance analog variation defines the filtenna frequency of operation, which can be varied from 2.2 GHz to 3.4 GHz with an average bandwidth of 200 MHz, while maintaining the radiation characteristics of the UWB antenna. Simulated and measured filtenna results are shown according to varactor diode bias, demonstrating multiband operation using a compact planar design.

Abstract In this paper a 2-4 GHz microstrip IFM (Instantaneous Frequency Measurement) subsystem that uses Wilkinson power dividers, frequency discriminators based on band-stop filters and a DC arduino section is reported. The device uses band-stop filters as an alternative to delay lines, commonly used for IFM. The resonators are responsible for frequency adjustment, according to half guided wavelength resonator length, and the distance between the transmission line and the resonator. A fully micro-controlled 125 MHz resolution IFM subsystem is designed and tested. Results of the IFM subsystem composed by filters, 4-way power dividers and an Arduino board are described.

Abstract This paper proposes a new Frequency Selective Surface (FSS) with modifications on the Jerusalem Cross (JC) geometry to provide a multiband response. Fractal levels are created by introducing concentric self-similar JC copies in the original unit cell. This modification results in new dipoles at the structure which allows for the appearance of new bands proportional to these diploles’ lengths, while maintaining total unit cell size. Three fractal levels of the JC FSS are studied in this paper, and third level presents five resonant frequencies which are f1 = 1.78 GHz, f2 = 6.42 GHz, f3 = 8.69 GHz, f4 = 10.94 GHz and f5 = 12.98 GHz. Simulation results for the insertion loss (S21), surface current distribution and measurement results are presented.