نتایج جستجو برای: band structure

تعداد نتایج: 1673409  

M. Fartookzadeh, M. Kazerooni

This paper proposes a two way L and S band Gysel power divider/combiner that uses line to ground resistors. Step by step methods to obtain a wide isolation and transmission bandwidth are presented. A design that uses five resistors is selected and optimized based on Quasi Newton method. Then the Defected Microstrip Structure (DMS) and Defected Ground Structure (DGS) is used to obtain better tra...

حمدا... صالحی, , سید محمدحسینی, , ناصر شاه طهماسبی, ,

  The electronic structure, density of state (DOS) and electronic density of state inparaelectric cubic crystal Ba TiO3 are studied using full potential-linearized augmented plane wave (FP-LAPW) method in the framework of the density functional theory (DFT) with the generalized gradient approximation (GGA) by the WIEN2K package. The results show a direct band gap of 1.8 eV at the point in the B...

In the present paper a novel structure for optical channel drop filter (CDF) based on photonic crystal ring resonator with circular core has been proposed. In order to design the proposed CDF, the plan wave expansion (PWE) method is applied for calculation of band structure and photonic band gap while the transmission characteristics of proposed CDF have been calculated using the finite differe...

بیرانوند, راضیه, دادستانی, مهرداد,

Electronic and optical properties of calcium, strontium and barium chalcogenide compounds in NaCl structure are studied using the band structure results obtained through the full potential linearized augmented palne wave method. Different linear relationships are observed between theoretical band gap and 1/a2 (where a is lattice constant) for calcium, strontium and barium chalcogenide compounds...

Journal: :Physical Review Special Topics - Accelerators and Beams 2011

Using the Dirichlet-Neumann mapping method, we were able to calculate the photonic band structure of the annular metal photonic crystals. The surveyed grid is square and scattering centers (bars) are in the form of air rings located on the metal surface, as well as metal rings located in the air. The photonic band structure is calculated for both polarizations E and H for electromagnetic waves....

H.J Xiang, X.Y Yu Z.B Cheng Z.F Shi

A plate periodically bonded with piezoelectric patches on its surfaces is considered. The differential quadrature element method is used to solve the wave motion equation for the two-dimensional periodic structure. The method is very simple and easy to implement. Based on the method, band structures for in-plane wave propagating in the periodic piezoelectric plate are studied, from which the fr...

In this work, the formation of oxygen-vacancy defect in 3d metals-doped TiO2 anatase and rutile structures is first investigated. The systematic calculations of formation energy, crystalline stability, band structure and density of state (DOS) of TiO2 samples of anatase and rutile doped with 3d transition metals with and without oxygen defect is done using FHI-aims as a software package based o...

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