A scalable multi-allowed band bandpass filter demonstrating ultra-wide-bandwidth, excellent efficiency, and sharp band-edge transition

2010 ◽  
Author(s):  
Tsung-Yu Huang ◽  
Ta-Jen Yen
Keyword(s):  
Bandpass Filter ◽  
Band Edge ◽  
Wide Bandwidth ◽  
Sharp Band ◽  
Band Edge Transition

A band notch UWB bandpass filter using dual-stub-loaded multimode resonator with embedded spiral resonator

2013 ◽  
Vol 6 (2) ◽  
pp. 161-166 ◽  
Author(s):  
Pankaj Sarkar ◽  
Ishita Rakshit ◽  
Sharmili Adhikari ◽  
Manimala Pal ◽  
Rowdra Ghatak
Keyword(s):  
Insertion Loss ◽  
Close Agreement ◽  
Bandpass Filter ◽  
Stop Band ◽  
Ultra Wideband ◽  
Band Edge ◽  
Electromagnetic Simulation ◽  
Transmission Zeros ◽  
Full Wave ◽  
Sharp Band

This paper presents a band-notched ultra-wideband bandpass filter by loading a short stub and an asymmetric step impedance stub in a uniform impedance resonator. The passband extends from 3.04 to 10.8 GHz frequency. The multimode resonator provides a sharp band edge with measured transmission zeros at 2.59 and 13 GHz. The later one is due to source load coupling. The passband insertion loss is within 1.5 dB. The embedded spiral resonator introduces a notch at 5.25 GHz with attenuation of 15 dB. The filter exhibits a wide stop band till 15 GHz. The in band and out of band performance obtained from full-wave electromagnetic simulation and measurement are in close agreement.

scholarly journals [Paper] Green Electroluminescence Generated by Band-edge Transition in Ag-In-Ga-S/GaSx Core/shell Quantum Dots

2021 ◽  
Vol 9 (4) ◽  
pp. 222-227
Author(s):  
Genichi Motomura ◽  
Yukiko Iwasaki ◽  
Tatsuya Kameyama ◽  
Tsukasa Torimoto ◽  
Taro Uematsu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Band Edge ◽  
Core Shell ◽  
Band Edge Transition

Compact, flexible and highly selective wideband complementary FSS with high angular stability

2021 ◽  
pp. 1-17
Author(s):  
Srimita Coomar ◽  
Santanu Mondal ◽  
Rajarshi Sanyal
Keyword(s):  
Dielectric Material ◽  
Incident Angle ◽  
Single Layer ◽  
Angular Stability ◽  
Band Edge ◽  
Transmission Line Model ◽  
Layer Structures ◽  
Sharp Band ◽  
Lc Circuit ◽  
Very High

Abstract This article presents a novel miniaturized (0.105λ0 × 0.105λ0) flexible complementary frequency selective surfaces (CFSS) structure with sharp band edge selectivity and very high angular stability. To explore two diverse applications as a passband and stopband filter, a novel complementary convoluted square loop (CCSL) type structure has been designed and investigated on ultrathin dielectric material of thickness 0.0023λ0. The second-order wide controllable passband with fractional bandwidth of 19.23% (−3 dB) and remarkably wide stopband of 64.7% (−10 dB) and 54.8% (−20 dB) respectively have been achieved by using a cascaded resonating structure which is composed of asymmetrical meandered CCSL array, arranged on two ultrathin dielectric layers with air foam separation. This particular format would lead to sharp band edge selectivity with steep roll-off (72.43 dB/GHz) and an excellent passband selectivity factor (0.731). An equivalent lumped LC circuit in conjunction with the transmission line model has also been adopted to comprehend the physical mechanism of the proposed single layer and double layer structures. Further, better passband and stopband angular stability at an oblique incident angle of 45° and the bending characteristics have also been investigated thoroughly for the proposed flexible CFSS to check their employability in different conformal structures with WiMAX passband and WLAN stopband application.

Effect of Different Mineralizers on Luminescence Characteristic of ZnO Crystals by Hydrothermal Method

2013 ◽  
Vol 848 ◽  
pp. 302-306
Author(s):  
Wen Li Zheng ◽  
Wei Yang
Keyword(s):  
Visible Light ◽  
Hydrothermal Method ◽  
Fill Factor ◽  
Crystal Morphology ◽  
Uv Light ◽  
Crystal Defects ◽  
Band Edge ◽  
Luminescence Characteristic ◽  
Amount Of Substance ◽  
Band Edge Transition

A comparative study worked on crystal morphology and luminescence characteristic by hydrothermal method with mineralizer of 3 mol /L KOH, fill factor of 35%, under the condition of three kinds of mineralizers which included 3 mol /L KOH in sample 1, 3 mol /L KOH and 1 mol /L LiOH in sample 2, 3 mol /L KOH and CaO: Zn ( OH) 2 = 2% (amount of substance percentage). Nonpolar ZnO crystals were synthesized by adding proper proportion of CaO or LiOH,the speed of growth along c-axic was weakened obviously. The obtained ZnO crystals exposed more areas on the positive polar face c { 0001}. meanwhile,it exposed negative polar-c {000},positive pyramidal face + p { 101},negative pyramidal face-p {10} and hexagonal faces m {1010}. Only KOH or LiOH auxiliarily added,the emission spectrum was only visible light,no UV light from band edge transition, indicating that the crystal defects luminous center are numerous. A strong UV band emitting from band edge transition was in luminescent spectrumn of the prepared crystals by adding CaO,which indicated a decrease in defects luminous center.

Characteristics of GaN/Si(111) Epitaxy Grown using Al0.1Ga0.9N/AlN Composite Nucleation Layers having Different Thicknesses of AlN

2002 ◽  
Vol 722 ◽  
Author(s):  
Seong-Hwan Jang ◽  
Seung-Jae Lee ◽  
In-Seok Seo ◽  
Haeng-Keun Ahn ◽  
Oh-Yeon Lee ◽  
...  
Keyword(s):  
Room Temperature ◽  
Growth Characteristics ◽  
Band Edge ◽  
Band Edge Emission ◽  
Yellow Luminescence ◽  
Edge Emission ◽  
Etch Pits ◽  
Nucleation Layer ◽  
Sharp Band ◽  
Surface Morphologies

AbstractWe have studied the effects of Al0.1Ga0.9N(150 nm)/AlN Composite Nucleation Layers (CNLs) having different thicknesses of AlN ranging from 20 to 41 nm on the growth characteristics of GaN/Si(111) epitaxy. The surface morphologies of the GaN epitaxial layers which were grown on Al0.1Ga0.9N(150nm)/AlN CNLs showed that the number of thermal etch pits and cracks was abruptly decreased with the increase of AlN thickness from 20 to 35 nm. However, the morphology of GaN epitaxy which was grown on Al0.1Ga0.9N(150 nm)/AlN CNL having AlN of 41 nm thick above 35 nm showed that the number of them was increased again. So, the GaN/Si(111) epitaxy which was grown using Al0.1Ga0.9N(150 nm)/AlN(35 nm) CNL showed the highest crystallinity having the FWHM of 1157 arcsec for the (0002) diffraction. Photoluminescence spectrum at room temperature for GaN/Si(111) epitaxy grown using Al0.1Ga0.9N(150 nm)/AlN(35 nm) CNL showed a sharp band edge emission at 364 nm, which especially doesn't have yellow luminescence related to various defects such as vacancy and dislocation. Meanwhile, the spectra at room temperature for the others showed yellow luminescence at around 580 nm except each band edge emission. Moreover, the FWHM of main exitonic peak at 10 K for the GaN/Si(111) epitaxy which was grown using Al0.1Ga0.9N(150 nm)/AlN(35 nm) CNL is the lowest value of 12.81 meV among them. It is obvious that the Al0.1Ga0.9N(150 nm)/AlN CNL having suitable thickness of AlN plays an important role in improving the crystallinity and optical properties of GaN/Si(111) heteroepitaxy without any defects such as pits and cracks over the surface by reducing the mismatch of thermal expansion coefficient and lattice constant between GaN and Si(111) comparing with AlxGa1-xN or AlN nucleation layer alone.

TUNING OF THE MAGNETIC FIELD INDUCED SHARP BAND-EDGE OPTICAL ABSORPTION IN EUROPIUM CHALCOGENIDES

2004 ◽  
Vol 18 (27n29) ◽  
pp. 3813-3816 ◽  
Author(s):  
A. B. HENRIQUES ◽  
L. K. HANAMOTO ◽  
E. TER HAAR ◽  
E. ABRAMOF ◽  
A. Y. UETA ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Optical Absorption ◽  
Low Temperatures ◽  
Optical Transition ◽  
Band Edge ◽  
Near Band Edge ◽  
High Magnetic Fields ◽  
Sharp Band ◽  
The Magnetic Field

The near band-edge polarized optical optical absortion spectra of EuTe at low temperatures and high magnetic fields were investigated. The samples were grown by MBE on BaF 2 substrates, and the thickness varied in the 0.18-2.0 μm range. At high magnetic fields, the well-known 4f7→4f65d(t2g) optical transition splits into two well resolved lines at σ+ and two lines for σ-. These lines can be described by localized transitions tunable by the d-f exchange interaction, with a quadratic dependence on the intensity of the external magnetic field. Comparative measurements of the magnetization and the optical absorption as a function temperature provides a further test of the model of a localized excitation extending over a few lattice sites.

Sign in / Sign up

Export Citation Format

Share Document