Electromagnetics at Arizona State University

Balanis, C.A.

doi:10.1109/74.210828

Cited by 4 publications

(4 citation statements)

References 54 publications

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“…Figure 1 shows the static and optical permittivity profile across a Si-SiO 2 interface as a function of position along the direction normal to the interface. The dielectric constants in the interior of SiO 2 and Si regions are in excellent agreement with experimental values of the corresponding bulk systems (static and optical values of about 12 for Si [39], and 4.5 and 2.5 for SiO 2 [40,41], respectively). However, in the transition region between Si and SiO 2 and close to the outer surface planes, we find an enhancement of the dielectric constant, compared to that of the bulk values.…”

Section: Si-sio 2 and Si-hfo 2 Interfacessupporting

confidence: 72%

Local properties at interfaces in nanodielectrics: An ab initio computational study

Shi

Ramprasad

2008

IEEE Trans. Dielect. Electr. Insul.

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First-principles computational methodologies are presented to study the impact of surfaces and interfaces on the dielectric and electronic properties of emerging technologically important systems over length scales of the order of inter-atomic distances. The variation of dielectric constant across Si-SiO 2 , Si-HfO 2 and SiO 2 -polymer interfaces has been correlated to interfacial chemical bonding environments, using the theory of the local dielectric permittivity. The local electronic structure variation across Si-HfO 2 and SiO 2 -polymer interfaces, including band bending, band offsets and the creation of interfacial trap states have been investigated using a layerdecomposed density of states analysis. These computational methods form the groundwork for a more thorough analysis of the impact of surfaces, interfaces, and atomic level defects on dielectric and electronic properties of a wide variety of nanostructured systems.

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Section: Si-sio 2 and Si-hfo 2 Interfacessupporting

confidence: 72%

Local properties at interfaces in nanodielectrics: An ab initio computational study

Shi

Ramprasad

2008

IEEE Trans. Dielect. Electr. Insul.

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“…From the figure, we can see that the dielectric constant in the inner layers away from the surface approach the bulk Si value of about 12 for both optical and static cases, in good agreement with experimental estimates. 39 At the region within 3 Å of the surfaces, the polarization and dielectric constant increase from the bulk values in the static case due to the emergence of ionic character of bonds close to the surface. Termination of the free slab surfaces with H atoms results in a small reduction in the polarization and dielectric constant enhancement at the slab surfaces.…”

Section: A Si and C 12 H 26 (Polymer) Slabsmentioning

confidence: 99%

Atomic-scale dielectric permittivity profiles in slabs and multilayers

Shi

Ramprasad

2006

Phys. Rev. B

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A recently developed theory of atomic-scale local dielectric permittivity has been used to determine the position dependent permittivity profiles of a few nanoscale insulator surfaces and multilayers. Specifically, slabs containing single-component ͑Si, polymer, and SiO 2 ͒ and two-component ͑Si-SiO 2 and polymer-SiO 2 ͒ systems of technological importance have been studied. The present approach indicates that the local permittivity is generally enhanced at the surfaces and/or interfaces, and that it approaches the corresponding bulk values in the interior of each component. This simple method of determining the position-dependent dielectric permittivity profiles can be used to study the impact of atomic level disorder and defects on dielectric properties.

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“…The antenna resonance frequency is about 6.39 GHz, which is in the C-frequency band and is powered by a 50 ohm coaxial SMA probe. Also, all the dimensions of this antenna were calculated and designed according to the standard formulas presented in [9]. Figure 1 shows the structure of the designed antenna.…”

Section: Description Of the Designed Antennamentioning

confidence: 99%

“…If the antennas are placed next to each other in an array [5] (both in receiver and transmitter modes), an undesired coupling occurs between the two antenna radiators elements, due to the reciprocal coupling of electric fields [6] which is induced from the first radiating element to the second radiating element and causes current to flow on the second radiating element, which is called the undesired electromagnetic coupling effect of the reciprocating coupling [7]. This mutual coupling becomes important when the ratio of the thickness of the sublayer to the wavelength of the free space is l where h is the thickness of the substrate, l 0 is the wavelength of the free space and e r is the relative permittivity or dielectric constant of the substrate.This effect depends on the type of antenna and its design parameters, the relative position of the elements in the array (the distance between the two antennas is inversely related to the amount of coupling between the two antennas), and the power supply of the array elements [9]. In a typical array, to properly isolate the radiators and the antenna, the distance between the radiators is at least l .…”

Section: Introductionmentioning

confidence: 99%

Reduction of mutual coupling in a microstrip array antenna with circular polarization in the C-frequency band using a combination of DGS and EBG methods

et al. 2023

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In dis study, in teh first stage, an antenna wif circular polarization was designed wif teh technique of cutting teh corners of radiation patches. Tan a hybrid structure wif DGS and EBG methods was presented. For dis purpose, teh designed structure of teh combination of DGS and EBG, which was designed to reduce mutual coupling, was placed between teh radiating elements of teh antenna. dis method is implemented on a microstrip antenna. Teh reduction of teh coupling of dis structure is based on teh creation of a magnetic band gap. All simulation was performed numerically by CST Microwave Studio software. Teh simulation results showed dat dis structure, unlike previous structures, improves all teh characteristics of teh antenna, such as teh antenna gain, antenna radiation efficiency, and antenna envelope correlation coefficient. Also, teh resonant frequency of teh antenna is 6.35 GHz, which reduces teh coupling by 36.5 dB by placing teh designed structure between teh radiating elements of teh antenna.

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Electromagnetics at Arizona State University

Cited by 4 publications

References 54 publications

Local properties at interfaces in nanodielectrics: An ab initio computational study

Local properties at interfaces in nanodielectrics: An ab initio computational study

Atomic-scale dielectric permittivity profiles in slabs and multilayers

Reduction of mutual coupling in a microstrip array antenna with circular polarization in the C-frequency band using a combination of DGS and EBG methods

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