PARAMETERS THAT AFFECT PARALLEL PROCESSING FOR COMPUTATIONAL ELECTROMAGNETIC SIMULATION CODES ON HIGH PERFORMANCE COMPUTING CLUSTERS

What is the impact of multicore and associated advanced technologies on computational software for science? Most researchers and students have multicore laptops or desktops for their research and they need computing power to run computational software packages. Computing power was initially derived from Central Processing Unit (CPU) clock speed. That changed when increases in clock speed became constrained by power requirements. Chip manufacturers turned to multicore CPU architectures and associated technological advancements to create the CPUs for the future. Most software applications benefited by the increased computing power the same way that increases in clock speed helped applications run faster. However, for Computational ElectroMagnetics (CEM) software developers, this change was not an obvious benefit – it appeared to be a detriment. Developers were challenged to find a way to correctly utilize the advancements in hardware so that their codes could benefit. The solution was parallelization and this dissertation details the investigation to address these challenges. Prior to multicore CPUs, advanced computer technologies were compared with the performance using benchmark software and the metric was FLoting-point Operations Per Seconds (FLOPS) which indicates system performance for scientific applications that make heavy use of floating-point calculations. Is FLOPS an effective metric for parallelized CEM simulation tools on new multicore system? Parallel CEM software needs to be benchmarked not only by FLOPS but also by the performance of other parameters related to type and utilization of the hardware, such as CPU, Random Access Memory (RAM), hard disk, network, etc. The codes need to be optimized for more than just FLOPs and new parameters must be included in benchmarking. In this dissertation, the parallel CEM software named High Order Basis Based Integral Equation Solver (HOBBIES) is introduced. This code was developed to address the needs of the changing computer hardware platforms in order to provide fast, accurate and efficient solutions to large, complex electromagnetic problems. The research in this dissertation proves that the performance of parallel code is intimately related to the configuration of the computer hardware and can be maximized for different hardware platforms. To benchmark and optimize the performance of parallel CEM software, a variety of large, complex projects are created and executed on a variety of computer platforms. The computer platforms used in this research are detailed in this dissertation. The projects run as benchmarks are also described in detail and results are presented. The parameters that affect parallel CEM software on High Performance Computing Clusters (HPCC) are investigated. This research demonstrates methods to maximize the performance of parallel CEM software code

MIMO antennas for mobile phone applications

Recent evolutions in wireless mobile communications have shown that by employing multiple inputs and multiple outputs (MIMO) technology at both the transmitter and receiver, both the wireless system capacity and reliability can be enhanced without the need for increasing the power transmitted or using more spectrum. Despite a considerable amount of research have been done on the design of MIMO and diversity handset antennas, the design of low profile, small footprint and multi-standard (wideband or multiband) diversity antennas on handset devices remains a challenging issue. Therefore, the purpose of this thesis is to present new antenna structures for handset MIMO and diversity applications. As the MIMO antenna design can be conducted either using multiple element antennas (MEA) or isolated mode antenna technology (IMAT), the work in this thesis is fallen in these two general design themes (areas). The first area under investigation concerns multiport antennas (IMAT antennas). It has the following two contributions: • A novel dual-feed water-based antenna is designed from a low cost liquid material with a very high dielectric constant (pure water ). The isolation between feeds is achieved by two back to back L-shaped ground plane strips. A prototype is made and the optimised diversity parameters are obtained, the results show that this design has a good diversity performance over the frequency range of 2.4 – 2.7 GHz. • A new and low profile (h = 3 mm) planar inverted-F antenna (PIFA) with a coplanar-feed is presented. It has a wideband response over the frequency range of 2.35 – 3.25 GHz. The design is based on a comparative study on the mutual coupling between different feed arrangements. As a result, the coplanar feed is employed in the proposed antenna; the polarization diversity is achieved by exciting two orthogonal radiation modes. The isolation between the feeds is achieved by an L-shaped ground plane slot. Both simulated and measured results demonstrate that the design is a very good candidate for mobile diversity and MIMO applications. The second investigation area concerns multiple element antenna (MEA) systems for wideband and multiband handset applications. It includes the following contributions: • Three antenna systems of the planar inverted-L (PILA) antenna (h = 5 mm) are employed for wideband handset diversity applications over the frequency range of 1.7 – 2.85 GHz: 1) The first design has a dual-element PILA in which both the pattern and spatial diversities are employed; one antenna element is located on the upper edge of the ground plane while the other is located on the lower edge. 2) The second design represents a more compact dual-element PILA antenna in which the two elements are placed on the same ground plane edge (collocated on the same edge). The antenna isolation is achieved using a parasitic decoupling element inserted between the two elements. A novel approach for the design of the parasitic decoupling element is proposed. It is based on stepped impedance resonator circuit theory. As a result, more space is saved with this design (footprint = 385 mm2) over the first design (footprint = 702 mm2). 3) The third design is a four-element PILA system in which two antenna pairs (one pair at the upper edge which the other pair is located on the lower edge on the system PCB). All the prototypes are made and evaluated; the results show excellent diversity performance over the applications in the frequency range of 1.7-2.7 GHz. • A dual-element hexa-band antenna is proposed for smartphone MIMO applications. It consists of two elements: a hexa-band metallic frame antenna and a hepta-band PILA antenna coupled with a meandered shorted strip as an internal antenna. The isolation is achieved due to the resulted orthogonal radiation patterns, especially, at 0.85 GHz. The optimized antenna is made and tested and the results show that this design covers a hexa-band and is particularly suitable for GSM850/ DCS1800/ PCS1900/ UMTS2100/ LTE2500/ LTE3600 smartphone applications

Design and analysis of wideband passive microwave devices using planar structures

A selected volume of work consisting of 84 published journal papers is presented to demonstrate the contributions made by the author in the last seven years of his work at the University of Queensland in the area of Microwave Engineering. The over-arching theme in the author’s works included in this volume is the engineering of novel passive microwave devices that are key components in the building of any microwave system. The author’s contribution covers innovative designs, design methods and analyses for the following key devices and associated systems: Wideband antennas and associated systems Band-notched and multiband antennas Directional couplers and associated systems Power dividers and associated systems Microwave filters Phase shifters Much of the motivation for the work arose from the desire to contribute to the engineering o

Unmanned Aircraft Systems in the Cyber Domain

Unmanned Aircraft Systems are an integral part of the US national critical infrastructure. The authors have endeavored to bring a breadth and quality of information to the reader that is unparalleled in the unclassified sphere. This textbook will fully immerse and engage the reader / student in the cyber-security considerations of this rapidly emerging technology that we know as unmanned aircraft systems (UAS). The first edition topics covered National Airspace (NAS) policy issues, information security (INFOSEC), UAS vulnerabilities in key systems (Sense and Avoid / SCADA), navigation and collision avoidance systems, stealth design, intelligence, surveillance and reconnaissance (ISR) platforms; weapons systems security; electronic warfare considerations; data-links, jamming, operational vulnerabilities and still-emerging political scenarios that affect US military / commercial decisions. This second edition discusses state-of-the-art technology issues facing US UAS designers. It focuses on counter unmanned aircraft systems (C-UAS) – especially research designed to mitigate and terminate threats by SWARMS. Topics include high-altitude platforms (HAPS) for wireless communications; C-UAS and large scale threats; acoustic countermeasures against SWARMS and building an Identify Friend or Foe (IFF) acoustic library; updates to the legal / regulatory landscape; UAS proliferation along the Chinese New Silk Road Sea / Land routes; and ethics in this new age of autonomous systems and artificial intelligence (AI).https://newprairiepress.org/ebooks/1027/thumbnail.jp

NASA Tech Briefs, February 1995

No abstract availabl

Dispersion Relations in Scattering and Antenna Problems

This dissertation deals with physical bounds on scattering and absorption of acoustic and electromagnetic waves. A general dispersion relation or sum rule for the extinction cross section of such waves is derived from the holomorphic properties of the scattering amplitude in the forward direction. The derivation is based on the forward scattering theorem via certain Herglotz functions and their asymptotic expansions in the low-frequency and high-frequency regimes. The result states that, for a given interacting target, there is only a limited amount of scattering and absorption available in the entire frequency range. The forward dispersion relation is shown to be valuable for a broad range of frequency domain problems involving acoustic and electromagnetic interaction with matter on a macroscopic scale. In the modeling of a metamaterial, i.e., an engineered composite material that gains its properties by its structure rather than its composition, it is demonstrated that for a narrow frequency band, such a material may possess extraordinary characteristics, but that tradeoffs are necessary to increase its usefulness over a larger bandwidth. The dispersion relation for electromagnetic waves is also applied to a large class of causal and reciprocal antennas to establish a priori estimates on the input impedance, partial realized gain, and bandwidth of electrically small and wideband antennas. The results are compared to the classical antenna bounds based on eigenfunction expansions, and it is demonstrated that the estimates presented in this dissertation offer sharper inequalities, and, more importantly, a new understanding of antenna dynamics in terms of low-frequency considerations. The dissertation consists of 11 scientific papers of which several have been published in peer-reviewed international journals. Both experimental results and numerical illustrations are included. The General Introduction addresses closely related subjects in theoretical physics and classical dispersion theory, e.g., the origin of the Kramers-Kronig relations, the mathematical foundations of Herglotz functions, the extinction paradox for scattering of waves and particles, and non-forward dispersion relations with application to the prediction of bistatic radar cross sections

Precision Agriculture Technology for Crop Farming

This book provides a review of precision agriculture technology development, followed by a presentation of the state-of-the-art and future requirements of precision agriculture technology. It presents different styles of precision agriculture technologies suitable for large scale mechanized farming; highly automated community-based mechanized production; and fully mechanized farming practices commonly seen in emerging economic regions. The book emphasizes the introduction of core technical features of sensing, data processing and interpretation technologies, crop modeling and production control theory, intelligent machinery and field robots for precision agriculture production