Engineering Commons^™

Fabricating Ordered 2-D Nano-Structured Arrays Using Nanosphere Lithography, Chenlong Zhang, Sandra Cvetanovic, Joshua M. Pearce

Joshua M. Pearce

Recent advances in the use of plasmonic metamaterials to improve absorption of light in thin-film solar photovoltaic devices has created a demand for a scalable method of patterning large areas with metal nanostructures deposited in an ordered array. This article describes two methods of fabricating ordered 2D nanosphere colloidal films: spin coating and interface coating. The two methods are compared and parameter optimization discussed. The study reveals that:

• For smaller nanosphere sizes, spin coating is more favorable, while for larger nanospheres, the angled interface coating provides more coverage and uniformity.

• A surfactant-free approach for interface coating is developed …

Development Of Impedance Spectroscopy Based In-Situ, Self-Calibrating, On-Board Wireless Sensor With Inbuilt Metamaterial Inspired Small Antenna For Constituent Detection In Multi-Phase Mixtures Like Soil, Gunjan Pandey

Gunjan Pandey

Real time and accurate measurement of sub-surface soil moisture and nutrients is critical for agricultural and environmental studies. This work presents a novel on-board solution for a robust, accurate and self-calibrating soil moisture and nutrient sensor with inbuilt wireless transmission and reception capability that makes it ideally suited to act as a node in a network spread over a large area. The sensor works on the principle of soil impedance measurement by comparing the amplitude and phase of signals incident on and reflected from the soil in proximity of the sensor. The permittivity of the soil dielectric mixture which is …

A Microstrip Tunable Negative Refractive Index Metamaterial And Phase Shifter, P. He, J. Gao, C. Marinis, P. Parimi, C. Vittoria, V. Harris

Vincent G. Harris

A tunable negative refractive index metamaterial and miniature phase shifter have been designed and fabricated in a microstrip configuration for applications in radio frequency integrated circuits. The metamaterial consists of plasmonic copper wires and yttrium iron garnet slabs having a low insertion loss of 5 dB at the center of the transmission band. The yttrium iron garnet material enables the magnetic field tuning of the negative refractive index in a dynamic frequency band from 7.0 to 11.0 GHz. The insertion phase can be tuned by 45 degrees continuously by varying the bias field from 3.8 to 4.6 kOe at 9.0 …

A Microstrip Tunable Negative Refractive Index Metamaterial And Phase Shifter, P. He, J. Gao, C. T. Marinis, P. V. Parimi, C. Vittoria, V. G. Harris

Carmine Vittoria

A tunable negative refractive index metamaterial and miniature phase shifter have been designed and fabricated in a microstrip configuration for applications in radio frequency integrated circuits. The metamaterial consists of plasmonic copper wires and yttrium iron garnet slabs having a low insertion loss of 5 dB at the center of the transmission band. The yttrium iron garnet material enables the magnetic field tuning of the negative refractive index in a dynamic frequency band from 7.0 to 11.0 GHz. The insertion phase can be tuned by 45 degrees continuously by varying the bias field from 3.8 to 4.6 kOe at 9.0 …

Guided Modes In A Waveguide Filled With A Pair Of Single-Negative (Sng), Double-Negative (Dng), And/Or Double-Positive (Dps) Layers, Andrea Alù, Nader Engheta

Nader Engheta

Here we present the results of our theoretical analysis for guided modes in parallel-plate waveguides filled with pairs of parallel layers made of any two of the following materials: 1) a material with negative real permittivity, but positive real permeability (epsilon-negative); 2) a material with negative real permeability, but positive real permittivity (mu-negative); 3) a material with both negative real permittivity and permeability (double-negative); and 4) a conventional material with both positive real permittivity and permeability (double-positive) in a given range of frequency. Salient properties of these guided modes are studied in terms of how these materials and their parameters …

Pairing An Epsilon-Negative Slab With A Mu-Negative Slab: Resonance, Tunneling And Transparency, Andrea Alù, Nader Engheta

Andrea Alù

Here, we analyze the transverse-magnetic (TM) wave interaction with a pair of slabs, one being an epsilon-negative (ENG) layer in which the real part of permittivity is assumed to be negative while its permeability has positive real part, and the other being a mu-negative (MNG) layer that has the real part of its permeability negative but its permittivity has positive real part. Although wave interaction with each slab by itself has predictable features, we show that the juxtaposition and pairing of such ENG and MNG slabs may, under certain conditions, lead to some unusual features, such as resonance, complete tunneling, …

Guided Modes In A Waveguide Filled With A Pair Of Single-Negative (Sng), Double-Negative (Dng), And/Or Double-Positive (Dps) Layers, Andrea Alù, Nader Engheta

Andrea Alù

Here we present the results of our theoretical analysis for guided modes in parallel-plate waveguides filled with pairs of parallel layers made of any two of the following materials: 1) a material with negative real permittivity, but positive real permeability (epsilon-negative); 2) a material with negative real permeability, but positive real permittivity (mu-negative); 3) a material with both negative real permittivity and permeability (double-negative); and 4) a conventional material with both positive real permittivity and permeability (double-positive) in a given range of frequency. Salient properties of these guided modes are studied in terms of how these materials and their parameters …