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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...
In this paper, it is illustrated how to carry out adaptive processing simultaneously at multiple frequencies using the same antenna array consisting of dissimilar antenna elements nonuniformly spaced and deployed above an imperfect ground plane. First, an electromagnetic transformation technique is described which can compensate for all non-ideal effects of an antenna array deployed in a real environment,...
In this paper, the distinction between Zenneck waves and surface plasmon polaritons is illustrated. Both are evanescent waves. The surface plasmon needs to be excited by an electron beam which can be effectively generated by a source of electrons or a quasiparticle like an evanescent wave which can tunnel through the medium and thus excite the electrons. This electron wave produces its own electromagnetic...
This document presents the application of a new electromagnetic in-house parallel EM simulator to the antenna analysis. The simulator is included in the commercial software HOBBIES. HOFEM makes use of a weak formulation based on double curl vector wave equation discretized with the higherorder isoparametric curl-conforming tetrahedral and triangular prismatic finite element rigorous implementations...
The far field of an antenna is generally considered to be the region where the outgoing wavefront is planar and the antenna radiation pattern has a polar variation and is independent of the distance from the antenna. In this paper, the starting distance for the far field is defined for antennas operating in free space and over an imperfect ground plane. First, this paper intends to illustrate that...
In electrical engineering, we obtain maximum average power from a source with some internal impedance when the connected load impedance equals the complex conjugate of the internal source impedance. This is known by the maximum power transfer theorem. Applying this theorem means that the best we can do is to distribute the source power equally between the source internal impedance and the load impedance;...
This short expository paper provides a brief introduction to ultrawideband (UWB) theory, technology, applications, and systems with a focus on radar and brief observations on communications. The definition of UWB radar is discussed, and an experimental UWB radar (Microwave Microscope) is considered to illustrate system properties and the imaging effectiveness of UWB transmissions.
The far field of an antenna is generally considered to be the region where the outgoing wavefront is planar and the antenna radiation pattern has a polar variation and is independent of the distance from the antenna. Hence, to generate a locally plane wave in the far field the radial component of the electric field must be negligible compared to the transverse component. Also, the ratio of the electric...
Received signal level measurements are frequently used to check the performance and the Quality Of Service (QOS) inside the coverage area in cellular networks. These expensive time consuming measurements are carried out using actual drive tests to assess the coverage area of a base station for a given cell and thus evaluate the QOS. In a drive test measurement system, a receiving antenna is placed...
The far field of an antenna is generally considered to be the region where the outgoing wavefront is planar and the antenna radiation pattern has a polar variation and is independent of the distance from the antenna. Hence, to generate a locally plane wave in the far field the radial component of the electric field must be negligible compared to the transverse component. Also, the ratio of the electric...
In electrical engineering, we obtain maximum average power from a source with some internal impedance when the connected load impedance equals the complex conjugate of the internal source impedance. This is known by the maximum power transfer theorem. Applying this theorem means that the best we can do is to distribute the source power equally between the source internal impedance and the load impedance;...
A hands-on approach to avoid scientific debates and confusions about surface waves and Zenneck waves are presented. The reflection coefficient for a TM incident wave on a flat boundary is studied as a function of the medium parameters in the most general way. When the second medium is lossy, the zero of this function results in a Zenneck wave and an infinite value represents a surface wave. Even though...
In this paper, we show how to eliminate shadow fading in cellular wireless system and discuss the main reason for such a phenomenon. One can deploy the transmitting antenna closer to the ground. In that case, the region of the variation in the field strength (shadow fading region) would be quite small and the field strength will decay monotonically inside the remainder of the cell area. We can improve...
The Electrically Small Antennas (ESAs) perform well compared to larger antennas under matched conditions. In this paper, we study the difficulties in achieving a good design of an ESA matched to 50 O system. These difficulties are summarized in three topics: First, the Quality (Q) factor of an ESA, in general, is high and cannot be less than the Chu limit. The Q factor of an antenna is inversely proportional...
In this paper, we study the performance of the Electrically Small Antennas (ESAs) versus larger antennas in both transmitting and receiving modes. We conclude that the ESAs perform well compared to larger antennas under matched conditions where the input power to the antenna is real (input power is S = VinIin, Vin and Iin are the phasor domain Root Mean Square (RMS) input voltage and input current,...
A new boundary integral method for solving the general Helmholtz equation has been developed starting from the frequency independent Laplace's equation. The new formulation is based on the Method of Moments solution of Laplace's equation. The main feature of this new formulation is that the boundary conditions are satisfied independent of the region node discretizations. The numerical solution of...
Corrosion inhibition performance of synthesized indoline compounds, namely, 3′-(4-(1-acetyl-5-(4-methoxyphenyl)-4,5-dihydro-1H-pyrazol-3-yl)phenyl)spiro[indoline-3,2′-thiazolidine]-2,4′-dione (MPIT) and 1-(4-(1-acetyl-5-(4-methoxyphenyl)-4,5-dihydro-1H-pyrazol-3-yl)phenyl)spiro[imidazolidine-2,3′-indoline]-2′,5-dione (MPII) on N80 steel in 15% HCl solution was studied using weight loss measurement,...
An electromagnetic in-house parallel EM solver for RCS computation of complex target is presented in this paper. The solver makes use of a weak formulation based on double curl vector wave equation discretized with the higher-order isoparametric curl-conforming tetrahedral finite element rigorous implementations of Nedelec first family of elements. For RCS analysis, a non-standard mesh truncation...
Received signal level measurements are frequently used to check the performance and the Quality of Service (QOS) coverage area in cellular networks. These expensive time consuming measurements are carried out using an actual drive tests to assess the coverage area of a base station for a given cell and thus evaluate the QOS. In this paper, the novelty of the proposed electromagnetic analysis technique...
Received signal level measurements are frequently used to check the performance and the Quality of Service (QOS) inside the coverage area in cellular networks. These expensive time consuming measurements are carried out using an actual drive tests to assess the coverage area of a base station for a given cell and thus evaluate the QOS. In this paper, the novelty of the proposed electromagnetic analysis...
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