Electric Coupler Research Articles

A directional coupler for partial discharge measurements in gas-insulated substations

This paper introduces a directional coupler for partial discharge (PD) measurements in gas-insulated substations (GIS). The sensor comprises a combination of magnetic and electric couplers, effectively segregating forward and backward pulses to enhance PD charge estimation and defect location. The sensor's design was supported with finite element method simulations and measurements conducted in a transverse electromagnetic test bench. Comparative analyses were performed against independent magnetic and electric couplers. The charge estimation and the directional coupler's directivity were evaluated in both the test bench and a full-scale GIS with different PD defects. Initially, the combined magnetic and the electric couplers exhibited undesired interactions, prompting corrective measures. Subsequent adjustments included changes to the electric coupler material and modifications to the magnetic coupler construction. The resulting high-voltage directional coupler performed better than the separated couplers in a GIS with discontinuities. This partial discharge sensor emerges as a candidate for future SF6-free alternative GIS.

Flexible Multi-Band Linearly Frequency Modulated Signal Generation Using a Single-Drive Mach–Zehnder Modulator

A photonic method for multi-band linearly frequency-modulated (LFM) signal generation is proposed and demonstrated experimentally. An intermediate-frequency (IF) LFM signal and a single-tone radio frequency (RF) signal are first coupled by an electrical coupler. Then the coupling signal is used to drive a single-drive Mach–Zehnder modulator (SDMZM). By properly setting the frequencies and corresponding modulation indices of the IF LFM signal and RF signal, the multi-band LFM signal can be generated. The number of sub-bands can be adjusted by simply controlling the direct current bias of the SDMZM. The proposed method features simple structure and flexible tunability, which is promising for modern multi-band radar systems.

Circular Polarized Ground Radiation Antenna for Mobile Applications

Here, we propose a ground radiation antenna (GradiAnt) with circular polarization (CP) by applying the ground-mode tuning (GMT) technique to the ground plane. We demonstrate that a GradiAnt at an arbitrary location of the ground plane can simultaneously excite two orthogonal modes of the same magnitude, and the phase difference between the two modes can be adjusted via GMT to achieve CP in mobile antennas. The proposed GradiAnt can be viewed as a combination of an electric coupler (J-type) and magnetic coupler (M-type) to the modes of the ground plane, and both modes can be excited to the same amplitude by tuning the coupling-type. GMT, applied to the ground modes using inductor-connected metal strips, can generate a 90° phase difference between the two modes of the ground plane. The proposed antenna design generates a 6 dB axial ratio bandwidth of 140 MHz from 2.38 to 2.52 GHz in the $+\textit {z}$ -direction. Right-hand CP and left-hand CP in the $+\textit {z}$ -direction and $-\textit {z}$ -direction, respectively, are obtained. The tuning mechanism is presented, and measurements are taken to validate the proposed technique.

Design of expert system for train operational feasibility with Tsukamoto fuzzy inference system

Train is one of the most favorite mass transportation in the world. In 2017 train in Indonesia can bring about 341.605 passengers to many destinations. PT. Kereta Api Indonesia is a state owned enterprise that has responsibility to make sure that train is safe and works well. As we know that a train has several components to check. It is very difficult to identify whether a train is in a good condition or needs repairing. The purpose of this work is to proposes a model of operational feasibility by several main criteria: bogie, breaking system, boffer, electric coupler, and safety kit. In its experiment phase, this model uses Tsukamoto Fuzzy Inference System to decide that a train is in good condition or need repairing. In evaluation phase we compare this model with traditional method and this model shows exactly 99% of the same result. It is suggested for further work to include several methods such as Tsugeno and Mamdani fuzzy inference system.

Proposal of Solidly Mounted Resonator Type Functional Devices

New device configurations using a solidly mounted piezoelectric thin film resonator (SMR) are proposed. In addition to the piezoelectric layer for the excitation of vibration, an additional piezoelectric layer is added in the SMR. The additional piezoelectric layer functions as an electric coupler. The resonant frequency of the SMR can be electrically adjusted through the coupler. The filter configuration using the SMR with the coupler is proposed. Moreover, the possibility of fabricating a chip type SMR device is considered. Simulation results for the proposed devices are presented.

Large signal analysis of optical directional coupler modulators

Expressions are obtained for the output harmonic and intermodulation products of optical electrical coupler modulators driven by multisinusoidal input signals. The special case of relatively small input amplitudes is considered. The results are verified by comparisons with previously published results.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>