Search results for "Transmission line"
showing 10 items of 50 documents
Optimal Design of an X-Band, Fully-Coaxial, Easily-Tunable Broadband Power Equalizer for a Microwave Power Module
2020
A microwave power module (MPM), which is a hybrid combination of a solid-state power amplifier (SSPA) as a driver and a traveling-wave tube amplifier (TWT) as the final high power stage, is a high-power device largely used for radar applications. A gain equalizer is often required to flatten the TWT output power gain owing to its big gain fluctuations over the operating frequency range. In this paper, the design of an X-band, fully-coaxial, easily-tunable broadband power equalizer for an MPM is presented. The structure is composed of a coaxial waveguide as the main transmission line and a coaxial cavity loaded with absorbing material as a resonant unit. Sensitivity analyses of the attenuati…
TLM Nodes: A New Look at an Old Problem
2015
In this paper, an alternative perspective on the transmission line modeling (TLM) method concepts to unify previous work is presented. The procedure begins by discretizing Maxwell’s equations and proposing TLM equivalent models. Node voltage and mesh current definitions are provided in terms of link line contributions, compatible with stub currents and voltages. They allow obtaining an expression that relates incident and reflected pulses with no other condition required. With this unified approach, modeling of other situations is straightforward. 2-D cases, source implementation, and anisotropic media are described and numerically tested.
Maximizing energy transfer and RES integration using dynamic thermal rating. Italian TSO experience
2019
The production of electricity from wind and other renewable sources is rapidly increasing all over the world, causing significant changes in the management of electrical systems. The current structural asset is not adequate to manage this growing generation of energy. The hypothesis of construction of new power lines would mean taking into consideration economic, political and social problems. The following paper reports the experience gained by the Italian TSO, Terna S.p.A, on the use of the DTR (Dynamic Thermal Rating), which is able to dynamically calculate the real transport capacity of an overhead power line. The results obtained are en- couraging as they show how it is possible to inc…
A New Approach to the Modeling of Anisotropic Media with the Transmission Line Matrix Method
2021
A reformulation of the Transmission Line Matrix (TLM) method is presented to model non-dispersive anisotropic media. Two TLM-based solutions to solve this problem can already be found in the literature, each one with an interesting feature. One can be considered a more conceptual approach, close to the TLM fundamentals, which identifies each TLM in Maxwell’s equations with a specific line. But this simplicity is achieved at the expense of an increase in the memory storage requirements of a general situation. The second existing solution is a more powerful and general formulation that avoids this increase in memory storage. However, it is based on signal processing techniques and considerabl…
Impact of transparent conductive oxide on the admittance of thin film solar cells
2010
Abstract The impact of transparent electrically conducting oxide (TCO) on the admittance measurements of thin film p–i–n a-Si:H solar cells was investigated. Admittance measurements on solar cell devices, with different area and geometry, in a wide range of frequencies and biases were performed. The admittance measurements of the investigated solar cells, which use the TCO as an electrical contact, showed that the high frequency admittance per area unit depends on the area. This effect increases both with the probe frequency and the size of the solar cells. Transmission line model valid for strip geometry which explains how the resistivity of the TCO layer impacts the measured admittance of…
Efficient Design of Waveguide Manifold Multiplexers Based on Low-Order EM Distributed Models
2015
In this paper, a new systematic technique to design manifold-coupled multiplexers in waveguide technology is proposed. The new technique uses generalized low-order electromagnetic (EM) distributed models, which constitute a half-way point between the fast, but imprecise, analytical models, and the more accurate, but costly, full-wave EM models. The method can be applied to contiguous and noncontiguous channel multiplexers, in both E-plane or H-plane configurations. This paper covers the complete design procedure for manifold multiplexers, starting from the required specifications and finishing with the physical dimensions. After explaining the general design technique for multiplexers with …
EFFECTS OF THE PENETRATION OF WIND POWER IN THE BRAZILIAN ELECTRICITY MARKET
2016
Climate variability has been the main driver for renewables in the Brazilian electricity market. This article analyzes the vulnerabilities of the dependence on hydropower in renewable energy production due to climate variation, as well as wind power penetration in Brazil, given a set of wind industry policies. Despite Brazilian renewable energy increase, the study shows the impact in energy supply in north region, due to the lack of transmission infrastructure. In Brazil, the potential trade-offs between renewables growth, and transmission infrastructure inconsistencies in terms of policy implementation are not yet well analyzed. Simulation results show the potential conflicts between energ…
Transmission-line model to analyze a multistage polarizer rotator
1991
A simple transmission-line model to design a broadband system consisting of a multilayered polarization rotator that rotates the polarization plane of a linearly polarized electromagnetic wave is presented. A simulation program that permits the design of the rotator parameters was implemented, and a prototype was designed, manufactured, and tested. Comparisons between the theoretical results and measurements are given, and a good correspondence is found.
Cascadability and efficiency of a saturable absorber device inserted into a SMF transmission line for future 160-Gbit/s all-optical reshaping applica…
2007
In this prospective work, we analyze the cascadability and reshaping properties of a quantum well microcavity saturable absorber (SA) device cascaded inside a RZ-signal SMF-based transmission line to annihilate the ghost-pulse phenomenon taking place in the "...01010101..." 160-Gbit/s 2-bit pattern.
Power Line Communication in Medium Voltage Systems: Characterization of MV Cables
2008
The aim of this paper is to illustrate the development of a theoretical and experimental study on the characterization of medium voltage (MV) cables in the frequency range 25-200 kHz. Two transmission line configurations, line-ground and line-line, were considered in order to evaluate the main parameters, such as the characteristic impedance and the attenuation constant alpha. A simplified model of the line-ground configuration is proposed which allows one to evaluate the characteristic impedance and the attenuation constant by means of geometrical dimensions. The model was verified by experimental measurements on commonly used MV cables, RG7H1R, with an aluminium core of different sections…