Chiral metamaterial-based microwave sensors

A significant resonance shift is found in both reflection and transmission coefficients from both parallel and perpendicular excitations in a helical structure. The responses from the perpendicular excitation show better sensitivity than those from the parallel excitation at 480 MHz-560 MHz for 0.2 circumference difference. Additional electromagnetic properties of a helical structure, such as chirality, optical rotatory dispersion and circular dichroism can also further combine to enhance the sensing performance

Graph-Based Semantic Web Service Composition for Healthcare Data Integration

Within the numerous and heterogeneous web services offered through different sources, automatic web services composition is the most convenient method for building complex business processes that permit invocation of multiple existing atomic services. The current solutions in functional web services composition lack autonomous queries of semantic matches within the parameters of web services, which are necessary in the composition of large-scale related services. In this paper, we propose a graph-based Semantic Web Services composition system consisting of two subsystems: management time and run time. The management-time subsystem is responsible for dependency graph preparation in which a dependency graph of related services is generated automatically according to the proposed semantic matchmaking rules. The run-time subsystem is responsible for discovering the potential web services and nonredundant web services composition of a user’s query using a graph-based searching algorithm. The proposed approach was applied to healthcare data integration in different health organizations and was evaluated according to two aspects: execution time measurement and correctness measurement

Flexible bi-layer terahertz chiral metamaterials

Thin and flexible bi-layer terahertz chiral metamaterials are experimentally demonstrated in both handednesses at terahertz frequencies. The structures are made of conjugated C8 metallic resonators fabricated on a flexible polyimide substrate. These structures exhibit chirality and can distinguish circularly polarized waves at the frequency range from 0.5 to 0.9 THz, equivalent to 57.15% bandwidth. The structures can be used as circular polarizers for terahertz waves.Amornthep Sonsilphong, Philipp Gutruf, Withawat Withayachumnankul, Derek Abbott, Madhu Bhaskaran, Sharath Sriram and Nantakan Wongkase

Controlling THz and far-IR waves with chiral and bianisotropic metamaterials

Chiral and bianisotropic metamaterials, where coupling of magnetic and electric phenomena plays an important role, offer advanced possibilities for the control and manipulation of electromagnetic waves. Such a control is particularly useful in the THz and far-IR region where natural materials do not show strong response and thus they are not offered as components for a direct realization of electromagnetic wave manipulation. Among the most useful and important capabilities of chiral and bianisotropic metamaterials is the advanced control of the wave polarization that they offer, including giant polarization rotation, conversion, filtering, absorption, etc. In this paper we review our recent work demonstrating some of those capabilities, in a variety of structures, both planar and 3D-bulk ones. The structures presented show, among others, large optical activity, tunable/switchable wave ellipticity, and polarization-dependent asymmetric transmission