Direct Laser Writing of Supercapacitors

Direct laser writing is a single-step fabrication technique for the micro and nanostructures even below the sub-diffraction limits. In recent times, the technique is adapted to the fabrication of on-chip energy storages with additional features of flexibility and stretchability. The major category of the energy storages taken into consideration for laser writing belongs to the family of supercapacitors which is known for the high rate of charge transfer, longer life spans and lesser charging times in comparison with traditional batteries. The technology explores the possibilities of non-explosive all solid-state energy storage integration with portable and wearable applications. These features can enable the development of self-powered autonomous devices, vehicles and self-reliant infrastructures. In this chapter, we discuss the progress, challenges and perspectives of micro-supercapacitors fabricated using direct laser writing

Advanced Radio Frequency Identification Design and Applications

Radio Frequency Identification (RFID) is a modern wireless data transmission and reception technique for applications including automatic identification, asset tracking and security surveillance. This book focuses on the advances in RFID tag antenna and ASIC design, novel chipless RFID tag design, security protocol enhancements along with some novel applications of RFID

Design and Analysis of Hexagonal Shaped Fractal Antennas

In this report three antenna designs using fractals have been proposed. Fractal is a concept which is being implemented in microstrip antenna to have better characteristics than conventional microstrip antenna. In the first design, a hexagonal shaped monopole fractal antenna for wideband application is designed. The proposed fractal-like geometry is implemented on a microstrip fed planar hexagonal monopole antenna. The iterated hexagonal fractal patch and modified ground plane are employed to achieve the desired wideband characteristics. A notch is also achieved by introducing slits in ground plane. In the second proposal, a new hexagonal shaped patch with modified hexagonal carpet ground plane antenna for multiband application is proposed. Its structure is based on carpet fractal geometry introduced in ground plane. The resonance frequency of a conventional hexagonal patch with full ground is lowered by removing carpet of hexagonal elements from the full ground plane. The antenna is optimized for a dual band operation. The last antenna is the smallest of all the three antennas obtained by taking a hexagonal patch of 8mm side on a fractal ground plane and whole dimension of 30x30mm2. Firstly, full ground plane is taken and studied. Then ground plane is modified by introducing and etching out Symmetrical Vertical Pyramidal Structure (SVPS). All antennas are simulated using CST Microwave Studio Suite 12. For all designs, low cost and readily available FR-4 substrate of relative permittivity of 4.4 and height 1.6mm has been used and fed with 50-ohm microstrip line. All antennas are measured to validate the simulated results. The measured antenna parameters such as return loss, radiation patterns and gain of the proposed antennas are found well matched to the simulated results

Design and Analysis of Fractal antennas

This report contains design proposals of three antennas with completely different functionalities. All of the three employ the concept of fractal geometry is designing compact antennas with better performance than Microstrip Patch antennas (MPAs). Fractals are one of the ripest fields of research for antenna design, their greatest merit being their ability to enhance electrical length while having virtually unaltered area and better performance. The first proposal is that of a hybrid fractal employing, two distinct categories of fractals, namely Sierpinski Carpet and Giuseppe Peanu, superimposed with each other to give Narrow-band functionality to the antenna. Resonating in the S-band it comes with a possibility to be employed for WiMAX applications. The second proposal is that of a multi-band fractal which again employs a self-similar iterative design. Carving circles out of squares while maintaining electrical conductivity throughout, the antenna results is multi-band functionality. Resonating at five distinct frequencies within the range of 3 GHz to 12 GHz, it has great scope of being employed for the applications that are possible within this range. The third proposal is that of an Ultra Wide band antenna whose fabrication gas also been carried out. Designed by carving hexagonal slots out of a circular patch this is the smallest of the three and optimisation is done using parametric analysis. All simulations are done in CST Microwave Studio. All of them are implemented on the readily available & low cost FR4 substrate of Er= 4.4.Antenna characteristics like radiation pattern and gain are analysed through simulations

SciTech News Volume 70, No. 4 (2016)

Columns and Reports From the Editor 3 Division News Science-Technology Division 4 SLA Annual Meeting 2016 Report (S. Kirk Cabeen Travel Stipend Award recipient) 6 Reflections on SLA Annual Meeting (Diane K. Foster International Student Travel Award recipient) 8 SLA Annual Meeting Report (Bonnie Hilditch International Librarian Award recipient)10 Chemistry Division 12 Engineering Division 15 Reflections from the 2016 SLA Conference (SPIE Digital Library Student Travel Stipend recipient)15 Fundamentals of Knowledge Management and Knowledge Services (IEEE Continuing Education Stipend recipient) 17 Makerspaces in Libraries: The Big Table, the Art Studio or Something Else? (by Jeremy Cusker) 19 Aerospace Section of the Engineering Division 21 Reviews Sci-Tech Book News Reviews 22 Advertisements IEEE 17 WeBuyBooks.net 2

Rigorous direct and inverse design of photonic-plasmonic nanostructures

Designing photonic-plasmonic nanostructures with desirable electromagnetic properties is a central problem in modern photonics engineering. As limited by available materials, engineering geometry of optical materials at both element and array levels becomes the key to solve this problem. In this thesis, I present my work on the development of novel methods and design strategies for photonic-plasmonic structures and metamaterials, including novel Green’s matrix-based spectral methods for predicting the optical properties of large-scale nanostructures of arbitrary geometry. From engineering elements to arrays, I begin my thesis addressing toroidal electrodynamics as an emerging approach to enhance light absorption in designed nanodisks by geometrically creating anapole configurations using high-index dielectric materials. This work demonstrates enhanced absorption rates driven by multipolar decomposition of current distributions involving toroidal multipole moments for the first time. I also present my work on designing helical nano-antennas using the rigorous Surface Integral Equations method. The helical nano-antennas feature unprecedented beam-forming and polarization tunability controlled by their geometrical parameters, and can be understood from the array perspective. In these projects, optimization of optical performances are translated into systematic study of identifiable geometric parameters. However, while array-geometry engineering presents multiple advantages, including physical intuition, versatility in design, and ease of fabrication, there is currently no rigorous and efficient solution for designing complex resonances in large-scale systems from an available set of geometrical parameters. In order to achieve this important goal, I developed an efficient numerical code based on the Green’s matrix method for modeling scattering by arbitrary arrays of coupled electric and magnetic dipoles, and show its relevance to the design of light localization and scattering resonances in deterministic aperiodic geometries. I will show how universal properties driven by the aperiodic geometries of the scattering arrays can be obtained by studying the spectral statistics of the corresponding Green’s matrices and how this approach leads to novel metamaterials for the visible and near-infrared spectral ranges. Within the thesis, I also present my collaborative works as examples of direct and inverse designs of nanostructures for photonics applications, including plasmonic sensing, optical antennas, and radiation shaping

A general quantitative cryptanalysis of permutation-only multimedia ciphers against plaintext attacks

In recent years secret permutations have been widely used for protecting different types of multimedia data, including speech files, digital images and videos. Based on a general model of permutation-only multimedia ciphers, this paper performs a quantitative cryptanalysis on the performance of these kind of ciphers against plaintext attacks. When the plaintext is of size $M\times N$ and with $L$ different levels of values, the following quantitative cryptanalytic findings have been concluded under the assumption of a uniform distribution of each element in the plaintext: 1) all permutation-only multimedia ciphers are practically insecure against known/chosen-plaintext attacks in the sense that only $O(log_L(MN))$ known/chosen plaintexts are sufficient to recover not less than (in an average sense) half elements of the plaintext; 2) the computational complexity of the known/chosen-plaintext attack is only $O(n\cdot(MN)^2)$, where n is the number of known/chosen plaintexts used. When the plaintext has a non-uniform distribution, the number of required plaintexts and the computational complexity is also discussed. Experiments are given to demonstrate the real performance of the known-plaintext attack for a typical permutation-only image cipher

Gold/graphene fractals as tunable plasmonic devices

Graphene, an atomically thin sheet of carbon atoms arranged in a honeycomb geometry, is attracting unique attention thanks to its extraordinary mechanical, electrical and optical properties. This thesis work concerns the realization of graphene-based nanoscale devices for novel plasmonic applications. We focus mainly on gold/graphene (Au/G) structures designed to display plasmonic multiresonances in the visible range thanks to the nanostructure geometry based on the Sierpinski carpet (SC) deterministic fractal