A Low Profile Asterick-Shaped Polarization Free Metamaterial-Inspired Absorber for Penta-Band Characteristics

A penta-band absorber is proposed and developed exhibiting ultra thin and polarization insensitive behavior. It has been designed to be operated in S, C and Ku bands with absorptions peaks at more than 95%. Proposed absorber is processed on a FR4 Glass Epoxy laminate with equivalent electrical thickness of 0.0108 λ0 where λ0 is the wavelength corresponding to the lowest frequency of operation. This confirms the ultra-thin nature of the structure. The absorption pattern of the proposed structure has been characterized under normal and oblique incidence followed by their experimental verification. Presented results demonstrate highly polarization-independent behavior of the proposed absorber due to its symmetric geometry. Also, the electromagnetic field distributions have been studied to acquire better insight of the absorption mechanism corresponding to distinct elements presented in the structure. Then the suggested structure is characterized in terms of its behavior as metamaterial, which ensures the miniaturization. The proposed absorber is suitable to be used in applications like radar cross section reduction, stealth technology, radio frequency identification and electromagnetic compatibility.

Study of Electrical Thickness Measurement System Technology of Composite

Based on four-terminal network theory, a multilayered model for reflective electrical thickness measurement system is presented in this paper. Using the simulation method of finite element, two crucial parameters of the measurement system are given. One parameter is the distance between the inner surface of composite and reflective mold, the other is the outer surface of composite and horn antenna aperture. This work will guarantee the design of the electrical thickness measurement system of composite.

Local Electrical Thickness-Mapping of Thin Oxides with Conducting Atomic Force Microscopy

In this work, we introduce Conducting Atomic Force Microscopy (C-AFM) as a novel technique for the determination of the local effective electrical oxide thickness with a lateral resolution of a few nanometers and a thickness resolution in the sub ångström range. In this technique the conductive tip of an AFM, which is in mechanical contact with the bare oxide surface, is used as metal electrode to define a local MOS structure with nanometer lateral extension. Oxide thickness determination is done by fitting the local I-V curves to the well known Fowler Nordheim tunneling equation with a thickness sensitivity in the sub-ångström range. In addition, tunneling current images at constant applied voltage can be obtained simultaneously to the oxide surface topography. We present a scheme which allows the conversion of the tunneling current images into maps of the local electrical oxide thickness. Several examples demonstrate the versatile and far-reaching application of C-AFM to R&D and failure analysis

Theory of inductive shielding

A mathematical theory of low-frequency electromagnetic shielding is constructed on the basis that an appropriate set of boundary conditions can be derived to duplicate the effect of the shield's wall on the fields within the shield. Shields with electrically thin shells are considered in detail; mathematical methods that are best suited for computational purposes are presented for calculating the shielding effectiveness of such a shield of arbitrary shape. Shells with arbitrary electrical thickness are also treated, but in less detail, since the shielding problem involving this kind of shell is shown to be different from but no more general than the shielding problem involving electrically thin shells. Explicit results are given for shields of particular shape.