Lunar Titanium and Frequency‐Dependent Microwave Loss Tangent as Constrained by the Chang'E‐2 MRM and LRO Diviner Lunar Radiometers

2020 ◽  
Vol 125 (9) ◽  
Author(s):  
Matthew A. Siegler ◽  
Jianqing Feng ◽  
Paul G. Lucey ◽  
Rebecca R. Ghent ◽  
Paul O. Hayne ◽  
...  
Keyword(s):  
Loss Tangent ◽  
Frequency Dependent ◽  
Microwave Loss

scholarly journals Structural, Optical and Frequency Dependent Electrical Behaviour of Aluminum Nitride (ALN) Nanopowder

2019 ◽  
Vol 8 (3) ◽  
pp. 7928-7932
Keyword(s):  
Electrical Conductivity ◽  
Particle Size ◽  
Dielectric Permittivity ◽  
Aluminum Nitride ◽  
Loss Tangent ◽  
Raman Shift ◽  
Crystallographic Structure ◽  
Electrical Parameters ◽  
Frequency Dependent ◽  
Relative Loss

Aluminum nitride (AlN) is ceramic material. It has very high thermal and low electrical conductivity. The Variation of Various Electrical Parameters viz. Impedance (Z), Admittance (Y), Dielectric Permittivity ('), Relative Loss (''), Electrical Conductivity (), and Loss Tangent (Tan ) with frequency Dependence of Aluminum Nitride (AlN) Nano powder were studied. Scanning electron microscopy (SEM); Raman Spectroscopy; and X-ray diffraction (XRD) were used to analyse the surfaces and structures of aluminum nirtride nanopowder. It has been found that the particle size is of 36.15 nm and the crystallographic structure is amorphous. The surface morphology of the studied compound has been investigated by Scanning Election Microscopy (SEM) indicating the particles are in nanosize and characteristic range of diameters are in nanoscale. The electrical studies of the studied compound have been examined in order to acquire the electrical parameters (mainly dielectric permittivity, loss, conductivity, loss-tangent, impedance, and admittance). Small rise in the conductivity (with frequency dependent) has been observed due to the decrease in the particle size of the material.it is also observed that the relative permittivity ('), relative loss '') and dissipation factor (Tan ) decreases with increase in frequency. The Raman shift variation with the intensity which shows the peaks of the compound are obtained at 506 cm-1 , 615 cm-1 656 cm-1 , 873 cm-1 , 882 cm-1 , 949 cm-1 , and 974 cm-1 using laser at 785 nm.

Conduction and Microwave Loss Mechanisms in Ba0.25Sr0.75TiO3 Films

2003 ◽  
Vol 784 ◽  
Author(s):  
Andrei Vorobiev ◽  
Par Rundqvist ◽  
Khaled Khamchane ◽  
Spartak Gevorgian
Keyword(s):  
Loss Tangent ◽  
Thermal Excitation ◽  
Low Loss ◽  
Loss Mechanism ◽  
Microwave Frequencies ◽  
Microwave Loss ◽  
Bst Thin Film ◽  
Dc Current ◽  
Charged Defects ◽  
Loss Mechanisms

ABSTRACTSilicon integrated parallel-plate Ba0.25Sr0.75TiO3 (BST) thin film varactors with Au bottom electrode have been prepared and characterized at dc and microwave frequencies. In the frequency range 0.045–45 GHz the varactors reveal extremely low loss tangent values (less than 0.025). However, this is still several times higher than loss in single crystal indicating occurrence of the extrinsic loss mechanisms. The analysis of BST film loss tangent and permittivity, depending on frequency and applied dc field, allow to attribute the dielectric loss to the charged defects. The dc current through varactor is found to be controlled by Poole-Frenkel mechanism associated with field enhanced thermal excitation of charge carriers from internal traps. It is assumed that charged defects and internal traps are the same type of BST film microstructure imperfection and possibly ascribed to be oxygen vacancies. The knowledge of the extrinsic loss mechanism and corresponding microstructure defects allows to optimize the deposition and/or anneal process and further improve the varactor performance.

Frequency-dependent loss tangent and power factor of magnetic fluids

2001 ◽  
Vol 226-230 ◽  
pp. 1887-1889 ◽  
Author(s):  
P.C. Fannin ◽  
A.T. Giannitsis ◽  
S.W. Charles
Keyword(s):  
Power Factor ◽  
Loss Tangent ◽  
Magnetic Fluids ◽  
Frequency Dependent

A LTCC Material with Low Temperature Coefficient of Resonance Frequency

2006 ◽  
Vol 301 ◽  
pp. 105-108 ◽  
Author(s):  
Masaru Iwao ◽  
Yoshio Umayahara ◽  
Kazuyoshi Shindo
Keyword(s):  
Resonance Frequency ◽  
Temperature Coefficient ◽  
Loss Tangent ◽  
High Frequency ◽  
Low Loss ◽  
Fixed Amount ◽  
Passive Components ◽  
Microwave Loss ◽  
Crystal Phases ◽  
Layered Ceramic

For high frequency packaging applications, LTCC materials are required to have a low loss tangent to reduce the total microwave loss. For multi-layered ceramic devices with embedded passive components, besides a loss tangent, a small temperature coefficient of resonance frequency (TCF) is an important factor. To meet these demands, we developed a new LTCC material with a smaller TCF, less than +/-3ppm/oC, and a low loss tangent, 0.0012 at 15GHz. We designed the glass composition to precipitate two low-loss crystal phases during firing at 900 oC. One phase has a plus TCF and the other phase has a minus TCF. We also controlled the amount of the two crystal phases, so these crystal phases and the fixed amount of alumina filler make the sum of TCF for the LTCC material close to zero.

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