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In order to increase the efficiency of thin-film solar cells, the nanostructure of these cells has to be optimized. To this end, simulations of the optical wave in thin-film solar cells are required. The frequency dependence of the refraction index of materials, like amorphous silicon (a-Si:H), cannot be described by dispersive models like Drude model. Therefore, single frequency simulations for the...
The nature of reflectarray (RA) optimization problems is intrinsically multi-target and therefore the use of a multi-objective optimization scheme is particularly convenient, although it can be computationally expensive. In this paper some considerations on the characterization and optimization of a RA are presented. The results of the use of efficient approaches for the modeling of the planar RA...
Mathematically strong and numerically efficient approach for simulation of waveguides and cylindrical resonators of arbitrary profile in the case of H-(TE-) polarized waves is suggested. The approach is based on new implementation of Analytical Regularization Method. Special attention paid to methods of the profiles infinitely smoothing, which gives a possibility to achieve a super-algebraic (faster...
The size reduction for resonant monopoles is an important issue for HF and VHF antennas. Unfortunately, size reduction results in degradation in both efficiency and bandwidth, as is well known from the fundamental limits on small antennas. This paper firstly introduces a MATLAB-controlled NEC2 simulation tool with genetic algorithm optimization, and uses this to find the optimal position of inductors...
We are developing a sensitive magnetic tensor gradiometer for detection of underwater unexploded ordnance (UXO) using high temperature superconducting quantum interference devices (SQUIDs). In parallel with the instrument development, we are looking at the challenges of making electromagnetic field and gradient measurements in electrically conductive seawater. We have been carrying out a theoretical...
Research at the Frequency Standards and Metrology Laboratories at the University of Western Australia has involved the invention, creation and applications of precise frequency generation and measurement. In recent years we have pursued a range of research topics from tests of fundamental physics to commercial and space applications. The symbiotic relationship between applied and fundamental related...
A generalized geometrical optics type locally Floquet field expansion is presented for describing the field transmitted through a plane periodic wall when it is illuminated by a nearby antenna. It is developed from a rigorous plane wave spectral integral for the field associated with this problem, and the integral is evaluated asymptotically via a double stationary phase approach. This ray expansion...
Plasmon resonances are able to produce a large field enhancement, which can be exploited for various purposes, such as biosensing or optical mixing. In this paper, the plasmon resonance of two stacked gold nanodisks separated by a tiny 2 nm gap is studied in time-domain simulations, offering the possibility of transient and broadband analysis. Moreover, time-domain simulations are amenable to extensions...
The design of a wideband orthomode transducer (OMT) with an integrated directional coupler for radio astronomy applications in the frequency range 900 MHz to 1760 MHz is presented. The OMT has very low insertion and transmission losses, good isolation, and is of small size.
In this paper, a novel rectangular patch antenna is proposed to have Zeroth Order Resonance(ZOR) at 2.4GHz generated based on the Metamaterial Complosite Right- and Left-Handed(CRLH) structure.
Traditional high-value monostatic imaging systems employ frequency-diverse pulses to form images from small synthetic apertures. In contrast, RF tomography utilizes a network of spatially diverse sensors to trade geometric diversity for bandwidth, permitting images to be formed with narrowband waveforms. Such a system could use inexpensive sensors with minimal ADC requirements, provide multiple viewpoints...
The magnetised plasma of near-Earth space (magnetosphere) supports two ultra-low frequency (ULF; 1-100 mHz), magnetohydrodynamic (MHD) oscillations known as the shear and fast Alfvén wave modes. The fast mode propagates across the ambient magnetic field, spreading ULF wave energy throughout the magnetosphere. For sufficiently large ionosphere conductance, the shear Alfvén mode forms field line resonances...
This paper describes the application of the analytical regularization method to the solution of electrostatic problem for several charged coaxial surfaces of revolution of arbitrary profile. The surfaces may be closed or open.
In order to solve complex electromagnetic radiation or scattering problems, there is often not a single method of choice. Different components or parts of such a complex problem are best solved with different numerical techniques, which then also need to be coupled within a hybrid framework. This paper provides an overview of a number of such hybrid techniques as available in the field solver package...
For some applications the use of metal backed substrates is advantageous. The solid backside-metallization provides a good heatsink and gives the possibility to produce MMIC-cavities by milling. However, the circuit design is bounded to one layer, and therefore the choice of suitable waveguide transitions is limited. Especially if right-angle transitions are needed, no structures are known to the...
We previously proposed a new coaxial-slot antenna of not whole conductor needle but one sandwiched dielectric between conductors for cancer therapy. The heating of the antenna was possessed of suppressed extension in the direction of the tip compared with that of the antenna of whole conductor needle, as a result of the experiment of liver phantom In this paper, we calculate the heating characteristics...
We examine the hopping dynamics of an artificial spin ice system constructed from colloids on a kagome optical trap array where each trap has two possible states. By applying an external drive from an electric field which is analogous to a biasing applied magnetic field for real spin systems, we can create polarized states that obey the spin-ice rules of two spins in and one spin out at each vertex...
In the paper, a survey of finite-element techniques developed for the numerical analysis of composite objects is presented. The computations are performed both in time domain and in frequency domain in parallel. For both the domains, perfectly matched layers have been developed to analyze open problems. In order to model sharp pulses followed by a long tail, adaptive time sampling has been proposed...
This paper presents a methodology to improve the performance of an UWB circular monopole antenna fed with a coplanar waveguide by coupling the waveguide slowly into the radiating element using a pre-defined curve that satisfies boundary conditions on the contour and its derivatives. The resulting antenna is modelled in Matlab and then transferred to CAD programs for simulation and manufacture using...
We consider the problem of reducing, in a given angular sector ΔΩ and at a given frequency, the time-harmonic far-held scattered from a perfectly conducting (PEC) surface Γ, or radiated by an antenna array made up of sources located in front of a PEC surface Γ.
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