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The far field pattern from a non-uniformly spaced antenna array is computed using a least squares method. The method originally developed for spectral estimation for a non-uniformly spaced finite data set is applied for the analysis of the far field pattern from unevenly spaced antennas, as the far field pattern is due to the spectrum of the location of the antenna elements. The advantage of using...
The impact of anomalous propagation such as sub refraction, super refraction and ducting on terrestrial paths is of great importance for microwave links. In this paper, 5 years (2009–2013) of measurement of climatological parameters such as pressure, temperature and relative humidity among others, at the ground surface and at the first 100 m altitude over five locations across Nigeria (Akure, Minna,...
In this paper, wideband and ultra wideband (UWB) radio propagation within a small aircraft was measured and statistically analyzed. Wideband including UWB wireless technology has been considered for replacing wire harnesses used in aircrafts, spacecraft, and other closed-or semi-closed spaces because of its anti-multipath capabilities and possible low power consumption. Adaptation of wireless technologies...
Broadcast television is one of the most important telecommunication systems in Brazil. Such relevance requires that an assessment of the coverage and quality of the Digital TV signal must be extensively performed in the pursuit of technical excellence. The study of coverage prediction models would allow broadcasters to project their stations in a way to distribute their respective signals harmoniously...
In this paper a dual-band antenna consisting of a double-ridged horn and a low-profile top-hat monopole, is introduced for unmanned aerial vehicle (UAV) applications. The horn is operating on a broad band from 2 GHz to 5.9 GHz with high gain in the bore sight direction to support high-speed data transmission; the low-profile top-hat monopole operates at a low frequency band from 430MHz to 450MHz and...
This work presents the station distribution for a radio interferometer with 192 dipole antennas. The general configuration is optimized for best detecting performances, reaching a sensitivity of 52 mJy for 1 hour observations.
The need for the reduction of energy consumption and size of microelectronic circuits is increasingly in demand. To support this request, this paper presents a comparison study on two integrated technologies: FDSOI 28nm and CMOS 350nm. The aim of this work was to compare the performance of these two technologies for the design of a rectifier and a Dickson charge pump for rectenna application. The...
This paper presents a brief analysis of the existing methods of reducing microstrip device dimensions. This paper also presents a miniaturization method based on using artificial transmission lines, which possess characteristics similar to those of quarter-wave transmission lines. Based on this method, a compact directional coupler, which divides the power in a 1:2 ratio, was designed and manufactured...
This paper proposes a very simple analytical formula for the magnetic field arising from single-circuit twisted three-phase cables as a tool to diagnose faults. Indeed, in the presence of cable faults the magnetic field around these cables increases dramatically. Then, by calculating the field with the formula using the current measured on one phase and by comparing the calculated and the measured...
The X-parameter model is designed for modeling weakly nonlinear devices in an approximately impedance-matched environment. Load dependent X-parameter models were proposed to overcome this, practically very relevant, limitation and model a nonlinear device in a highly mismatched environment. However, the applicability of load dependent X-parameter models for DUTs operating in deep saturation like in...
This presentation focuses on the design and characterization process of an active array demonstrator for the mid-frequency range (i.e., 300 MHz-1000 MHz) of the future Square Kilometre Array (SKA) radio telescope. This demonstrator, called FIDA3 (FG-IGN: Fundación General Instituto Geográfico Nacional — Differential Active Antenna Array), is part of the Spanish contribution to the SKA project. The...
The aim of this contribution is the study of a multi-view electromagnetic scanner. In this system, the final image is dynamically built from several partial images taken from arbitrary views. Thus, the system opens the possibility to produce the surface profiling of an entire target without suffering shadow effects due to occlusions.
Maxwell's equations have been around for over 150 years since its inception. But due to their enduring legacy, their importance has not diminished over the years. In fact, electromagnetic theory finds applications in increasing number of areas and relationship to deeper mathematics. For instance, electromagnetics is important for quantum information, quantum optics, and increasingly being used in...
I will discuss low-frequency radio astronomy engineering efforts underway in Western Australia. We carry out this work through the International Centre for Radio Astronomy Research (ICRAR)/Curtin University. The frequency range of interest is ∼50 to ∼350 MHz, which is the Low-Frequency Square Kilometre Array (SKA-Low) frequency band. I will describe recent and current work in the Murchison Widefield...
In this study, totally 50 grammar school students were exposed (or sham exposed) to radiofrequency (RF) electromagnetic fields (EMF). The physiological variations in heart rate variability (HRV) were examined. The EM wave was used as a pulse modulated 1788.5 MHz sine wave generated by signal functional generator. In exposed group, a lying position was characterized by significant increase in parasympathetic...
For the application of a standardized numerical procedure for the specific absorption rate (SAR) assessment of a mobile phone, it is imperative to first validate the numerical model of the phone. For this purpose, it is proposed in the currently developed numerical SAR standards, to compare the simulated and measured SAR distributions for the configuration of the phone placed against a flat phantom...
Finite Difference Time domain techniques have some interesting features for simulating Very Low Frequency (VLF) antennas in realistic environments. Such multi-scale problems can be solved by using an arbitrary oriented thin wire model. For the Transmission Line Matrix (TLM) method, the definition of the interaction domain that links the wire model to the surrounding Cartesian mesh is a critical issue...
This paper continues the series of works devoted to the investigation of leaky-wave antenna based on layered rectangular waveguide with periodic transverse slots in broad face. Previously developed wavenumber calculation technique has been adapted for analysis of slotted sandwich waveguide with three layers at least. Velocity factor dependencies are presented for partially filled slotted rectangular...
The effect of thickness of a hollow post in a combline resonator on the resonant frequency, coupling coefficients and spurious performance are analysed. It is shown that both the electric and magnetic couplings are not significantly affected by the size of the thickness of the hollow post, whereas the resonant frequency and spurious free band both change. When the thickness of the hollow post reduces...
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