Current Search:  Time-domain analysis (x)

View All Items

  • CSV Spreadsheet
(1 - 3 of 3)
Analysis and design of simulated human bodies using the finite difference time domain method
Title
Analysis and design of simulated human bodies using the finite difference time domain method.
Creator
Napoles, Adrian., Florida Atlantic University, Bagby, Jonathan S., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
A three-dimensional finite difference time domain analysis of a saline water phantom used in industry for testing body-mounted receivers is presented. Specifically, a saline water phantom known as "Salty" is analyzed. Salty is an acrylic circular cylinder which is filled with a saline solution. The fields at the center of the cylinder and 1 cm external to the surface of the cylinder are obtained with the FDTD method for normally incident TMz and TEz plane wave excitation in free space. The...
Show moreA three-dimensional finite difference time domain analysis of a saline water phantom used in industry for testing body-mounted receivers is presented. Specifically, a saline water phantom known as "Salty" is analyzed. Salty is an acrylic circular cylinder which is filled with a saline solution. The fields at the center of the cylinder and 1 cm external to the surface of the cylinder are obtained with the FDTD method for normally incident TMz and TEz plane wave excitation in free space. The results from the FDTD simulation are then compared to the closed-form solution, which is obtained by assuming that Salty is infinitely long. A low dielectric constant simulated human body which emulates the performance of Salty is designed using the closed-form solution for the near fields of a two-layer cylinder and its performance is verified with the FDTD method.
Show less
Date Issued
1995
PURL
http://purl.flvc.org/fcla/dt/15215
Subject Headings
Time-domain analysis, Beepers (Pagers), Electromagnetic waves--Scattering--Mathematical models
Format
Document (PDF)
study on the electromagnetic performance of body-worn radio units in the presence of scatterers in the proximity
Title
A study on the electromagnetic performance of body-worn radio units in the presence of scatterers in the proximity.
Creator
Peterson, Vance Howard, Florida Atlantic University, Ungvichian, Vichate, Neelakanta, Perambur S., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
The research addressed refers to a study on the electromagnetic performance aspects of body-worn radio units operating in the presence of scatterers in close proximity, using analytical, numerical, and experimental methods. The application potentials of such methods include evaluating the integrity of radio units such as cell phones. Consistent with the scope of the study above, considered in this research are specific details on analytical and numerical modeling of the effects of a nearby...
Show moreThe research addressed refers to a study on the electromagnetic performance aspects of body-worn radio units operating in the presence of scatterers in close proximity, using analytical, numerical, and experimental methods. The application potentials of such methods include evaluating the integrity of radio units such as cell phones. Consistent with the scope of the study above, considered in this research are specific details on analytical and numerical modeling of the effects of a nearby conducting cylindrical object on the electromagnetic field near a human-model phantom. Calculations are performed using the Finite Difference Time Domain (FDTD) method. Considered are various separations of the body wearing the test radio unit from the proximal object and polarization of the incident wave. An anechoic chamber and the test setup used for the measurement of EM field amplitudes near a saline-water phantom are described. Within the anechoic chamber, a small shielded loop is used as a field measurement probe and is positioned near the test phantom. The field probe orientation was in the vertical plane for characterizing the prevailing electromagnetic field intensity. This study indicates that variations in the field amplitude near the phantom occur, which are responsive to phantom rotation and measurement distance from the phantom. The electromagnetic field amplitude decreases rapidly with increasing distance between the probe and the surface of the phantom. The analysis is also extended to examine the electromagnetic field distribution in the gap between a human body phantom model and a nearby conducting cylinder. An appropriate three-dimensional FDTD method is presented and applied to a near-field problem of analyzing the influence of proximal conductive objects on fields near a phantom wearing an RF unit.
Show less
Date Issued
2004
PURL
http://purl.flvc.org/fau/fd/FADT12085
Subject Headings
Scattering (Mathematics), Sound-waves (Scattering), Electromagnetic waves--Scattering, Electromagnetism--Computer simulation, Finite differences, Time-domain analysis
Format
Document (PDF)
Effects of Adaptive Antenna Array Beamforming and Power Management with Antenna Element Selection
Title
Effects of Adaptive Antenna Array Beamforming and Power Management with Antenna Element Selection.
Creator
Abazari Aghdam, Sajjad, Bagby, Jonathan S., Florida Atlantic University, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
This research is the array processing help wireless communication techniques to increase the signal accuracy. This technique has an important part of prevalent applications. The wireless communication system, radar, and sonar. Beamforming is one of methods in array processing that filters signals based on their capture time at each element in an array of antennas spatially. Numerous studies in adaptive array processing have been proposed in the last several decades, which are divided in two...
Show moreThis research is the array processing help wireless communication techniques to increase the signal accuracy. This technique has an important part of prevalent applications. The wireless communication system, radar, and sonar. Beamforming is one of methods in array processing that filters signals based on their capture time at each element in an array of antennas spatially. Numerous studies in adaptive array processing have been proposed in the last several decades, which are divided in two parts. The first one related to non-adaptive beamforming techniques and the next one related to digitally adaptive Beamforming methods. The trade-off between computational complexity and performance make them different. In this thesis, we concentrate on the expansion of array processing algorithms in both non-adaptive and adaptive ones with application of beamforming in 4G mobile antenna and radar systems. The conventional and generalized side-lobe canceller (GSC) structures beamforming algorithms were employed with a phase array antenna that changed the phase of arrivals in array antenna with common phased array structure antennas. An eight-element uniform linear array (ULA), consisting of di-pole antennas, represented as the antenna array. An anechoic chamber measures the operation of beamforming algorithms performance. An extended modified Kaiser weighting function is proposed to make a semi-adaptive structure in phased array beamforming. This technique is extended to low complexity functions like hyperbolic cosine and exponential functions. Furthermore, these algorithms are used in GSC beamforming. The side-lobe levels were so lower than other algorithms in conventional beamforming around -10 dB. On the other hand, a uniform linear arrays for smart antenna purposes designed to utilize in implementing and testing the proposed algorithms. In this thesis, performance of smart antenna with rectangular aperture coupled microstrip linear array which experimental investigations carried out for obtaining X-band operation of rectangular microstrip antenna by using aperture coupled feeding technique. Frequency range set at approximately 8.6 to 10.9 GHz, by incorporating frequency range of the antenna resonates for single wideband with an impedance bandwidth of 23%. The enhancement of impedance bandwidth and gain does not affect the nature of broadside radiation characteristics. This thesis describes the design, operation, and realization of the beamforming such as Sidelobe level (SLL) control and null forming array antenna are examined with the prototype. An antenna radiation pattern beam maximum can be simultaneously placed towards the intended user or Signal of interest (SOl), and, ideally nulls can be positioned towards directions of interfering signals or signals not of interest (SNOIs). Finally, we focused on the adaptive digitally algorithms in compact antenna that faces with mutual coupling. The variable step-size normalized lease mean square (VS-NLMS) algorithm is implemented in beamforming. This algorithm utilizes continuous adaptation. The weights are attuned that the final weight vector to the most satisfied result. The gradient vector can be achieved by iterative beamforming algorithm from the available data. This algorithm is compared with LMS, NLMS, VSS-NLMS algorithms, it is determined that the VSS-NLMS algorithm is better performance to other algorithms. Finally, we introduced novel adaptive IP-NNLMS beamformer. This beamformer reaches to faster convergence and lower error floor than the previous adaptive beamformers even at low SNRs in presence of mutual coupling. The experimental results verified the simulation results that the proposed technique has better performance than other algorithms in various situations.
Show less
Date Issued
2016
PURL
http://purl.flvc.org/fau/fd/FA00004789, http://purl.flvc.org/fau/fd/FA00004789
Subject Headings
Global system for mobile communications., Long-Term Evolution (Telecommunications), Wireless communication systems., Antennas (Electronics), Antenna arrays., Array processors., Time-domain analysis.
Format
Document (PDF)