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An artificial or meta material was fabricated by printing I-shaped metal patterns periodically on a dielectric host medium to demonstrate frequency blocking property. The research was conducted by 3D electromagnetic simulation software first and then verified by several experiments. Experimental results showed that center frequency of blocked band could be controlled by adjusting the size and shape of I-shaped metal patterns. 

In this project, it was shown by simulation that the permittivity of a material could be enhanced by embedding metal inclusions in the host material. Later, a series of systematic experiments were carried out with free space material measurement equipment/system to demonstrate the enhancement of permittivity with circular metal patches printed periodically on a host material to validate the simulation results. 

A theoretical analysis is conducted to understand the role of dielectric loss component in the design process of a microwave absorber. The analysis starts with the determination of input impedance of the absorber and equating this to free space impedance in order to develop the impedance matching equation. The result of analysis showed that absorbing material must have some amount of loss component for impedance matching at a certain frequency and for perfect impedance matching a specific value of loss factor is required along with specific value of dielectric constant and material thickness. 

A microwave absorber is designed with a given absorbing material whose relative permittivity and permeability are known. In this design process, impedance matching between absorber and free space is achieved by circular metal patches of predesigned shape printed periodically on absorbing material. Designed microwave absorber along with predesigned designed metal strip is modeled in 3D electromagnetic simulation software HFSS. Simulated frequency response of reflection coefficient verifies impedance matching and absorption at design frequency. 

Understanding the nucleon spin structure in the regime where the strong interaction becomes truly strong poses a challenge to both experiment and theory. At energy scales below the nucleon mass of about 1 GeV, the intense interaction among the quarks and gluons inside the nucleon makes them highly correlated. Their coherent behaviour causes the emergence of effective degrees of freedom, requiring the application of non-perturbative techniques such as chiral effective field theory. Here we present measurements of the neutron’s generalized spin polarizabilities that quantify the neutron’s spin precession under electromagnetic fields at very low energy-momentum transfer squared down to 0.035 GeV2. In this regime, chiral effective field theory calculations are expected to be applicable. Our data, however, show a strong discrepancy with these predictions, presenting a challenge to the current description of the neutron’s spin properties.