Constant Field Distribution Research Articles

Inhomogeneous field in cavities of zero index metamaterials.

In common media, electromagnetic wave always possesses a fluctuant field variation, analogous to an undulant surface of sea. While electromagnetic wave in the media with zero index metamaterials (ZIMs), whose refractive indices are near zero, homogeneous or constant field distribution will emerge, resembling a tranquil surface of lake. Such impression almost could be found in all previous literatures related to ZIMs. However, in this letter, we theoretically and numerically find that, in a cavity structure with ZIMs, when higher order modes (e.g., dipole modes) are excited inside cavity, inhomogeneous field could take place in ZIMs. Such a finding challenges the common perception in ZIMs: It is generally considered that homogeneous or constant field is generated in ZIMs. In addition, the proposed cavity structure herein could be used to manipulate radiation of light, such as enhancing or suppressing radiation, controlling radiation pattern and achieving isotropic or directive radiation, thereby potential applications are expected. These effects are well confirmed by numerical simulations.

Thin-slot formalism for the FDTD analysis of narrow apertures having depth

A new thin-slot formalism is presented for the finite-difference time-domain (FDTD) analysis of the coupling of narrow apertures having depth. To derive the formalism, the equivalence principle is used to divide the slot coupling problem into three decoupled parts. The field distribution near the aperture is gained from the equivalent magnetic current together with a constant field distribution assumption. By incorporating the field distribution into the Ampere’s law and Faraday’s Law, the updated equations are derived to modify the electromagnetic field components near the apertures. Two numerical examples are adopted to verify the validity of the proposed formalism, and both the high-resolution standard FDTD results and FEKO (FEldberechnung Bei Körpern mit beliebiger Oberfläche) result are presented as references. The proposed formalism is verified to be a stable and accurate model for thin-slot coupling.

Modeling of reverse current behavior in amorphous thin and thick p-i-n diodes

We present an analytical model for the calculation of the nonuniform electric field distribution inside the three layers of an amorphous p-i-n diode. Field dependent Poole-Frenkel emission factors, responsible for the exponential voltage dependence of the dark current of amorphous p-i-n diodes are recalculated for the resulting nonuniform electric field distribution inside the intrinsic layer. Results are compared with experiments and with calculations using the constant field distribution approximation to show under which conditions each approach can be used.