THz Applications for the Engineering Approach to Modelling Frequency Dispersion within Normal Metals at Room Temperature

PIERS Online ◽  
2010 ◽  
Vol 6 (3) ◽  
pp. 293-299 ◽  
Author(s):  
Stepan Lucyszyn ◽  
Yun Zhou
Keyword(s):  
Room Temperature ◽  
Frequency Dispersion ◽  
Engineering Approach ◽  
Normal Metals ◽  
Thz Applications

Dielectric Behavior and Impedance Spectroscopy of Bi2Sr2GdCu2Oy

2003 ◽  
Vol 17 (21) ◽  
pp. 3847-3856 ◽  
Author(s):  
M. Chandrasekhar
Keyword(s):  
Activation Energy ◽  
Temperature Region ◽  
Ac Conductivity ◽  
Room Temperature ◽  
Complex Impedance ◽  
Frequency Dispersion ◽  
Solid State Reaction Method ◽  
Dielectric Behavior ◽  
Nominal Composition ◽  
Present System

Samples with the nominal composition Bi 2 Sr 2 GdCu 2 O y in Bi -2212 where Gd replaces Ca as well as samples without Gd were prepared by solid-state reaction method. From the room temperature X-ray diffraction data, the samples were found to be similar to the single phase Bi -2212 structure. Impedance studies were performed from room temperature to 423 K at different frequencies in the range of 10 to 700 KHz. The AC conductivity increases with temperature and frequency, exhibiting frequency dispersion at low temperature region. The activation energy from AC conductivity in the high temperature region is found to be 0.432 eV. The permitivity increases with the increase in temperature and at 373 K it shows a maximum value exhibiting a dielectric loss. Complex impedance spectra are analyzed in terms of bulk relaxation and interfacial effects. The activation energy of the dipoles involved in the relaxation was estimated to be 0.482 eV. The universal power law of Jonscher is verified in the present system.

THE DIELECTRIC PROPERTIES OF SELECTED BASALTS

Geophysics ◽  
1973 ◽  
Vol 38 (1) ◽  
pp. 135-139 ◽  
Author(s):  
W. Hansen ◽  
W. R. Sill ◽  
S. H. Ward
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Loss Tangent ◽  
Room Temperature ◽  
Frequency Dispersion ◽  
Nitrogen Atmosphere ◽  
Frequency Range ◽  
Dielectric Constant And Loss ◽  
Identical Composition ◽  
Titanium Compounds

Basaltic samples of known chemical composition were measured for dielectric constant and loss tangent in the frequency range 100 hz to 50 Mhz. All samples were prepared and measured by a contact substitution method in a dry nitrogen atmosphere at room temperature. The measurements indicated a general spectrum of dielectric constant with a range of 10–65 at 100 hz to 7–15 at 50 Mhz with frequency dispersion observed to be minimal above 1 Mhz. The loss tangent decreases from a range .2–.9 at 100 hz to a range .02–.15 at 100 khz. A finer‐grained sample was observed to have higher dielectric properties below 1 Mhz than a coarser‐grained sample of identical composition. A qualitative and subsequent quantitative study of possible compositional effects indicated that iron‐titanium compounds may be responsible for observed variations in the dielectric spectra of typical basalts.

Phase Transition and Dielectric Tunability of Chemical Solution Deposited (Pb0.35Sr0.65)(Zr0.5Ti0.5)O3 Thin Films on Pt/ZrO2/SiO2/Si Substrates

2007 ◽  
Vol 1034 ◽  
Author(s):  
Naba K Karan ◽  
Marilin Perez ◽  
Jose Saavedra ◽  
Dillip K Pradhan ◽  
Reji Thomas ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Seed Layer ◽  
Room Temperature ◽  
Single Phase ◽  
Frequency Dispersion ◽  
Chemical Solution ◽  
Solution Deposition ◽  
Si Substrates ◽  
Dielectric Constant And Loss

Abstract(Pb0.35Sr0.65)(Zr0.5Ti0.5)O3 thin films were grown on Pt/ZrO2/SiO2/Si substrates by chemical solution deposition. As-deposited (pyrolysed at 500°C) films were amorphous and single phase films were obtained at temperature as low as 550°C with a 30 nm SrTiO3 seed layer. Dielectric constant and loss tangent at room temperature were 210 and 0.022, respectively at 100 kHz for the film annealed at 700°C. Frequency dispersion of the dielectric properties was low. The phase transition temperature (ferroelectric to paraelectric) was well below the room temperature and was around 220 K. The room temperature tunability and the k-factor at 500 kV/cm was around 45% and 16, respectively.

Microwave Tuning Quality and Power Handling of Voltage-Tunable Capacitors: Semiconductor Varactors Versus Ba1−xSrxTiO3 Films

1997 ◽  
Vol 493 ◽  
Author(s):  
D. Gait ◽  
T. Rivkina ◽  
M. W. Cromar
Keyword(s):  
Room Temperature ◽  
Frequency Dispersion ◽  
Microwave Frequency ◽  
Third Order ◽  
Resonant Frequencies ◽  
Tunable Capacitors ◽  
Distortion Products ◽  
Power Handling ◽  
Weakly Coupled ◽  
Microstrip Resonators

ABSTRACTThin films of SrTiO3 and Ba0.4Sr0.6TiO3 have been pulse laser ablated onto LaAIO3 substrates. Normal metal coplanar capacitor electrodes were patterned on top of these films and the capacitors were incorporated into weakly coupled microstrip resonators. Resonant frequencies and Q's were measured as a function of bias at room temperature and at 77 K. The microwave frequency capacitance and loss is calculated from the resonant properties and compared with the simultaneously measured 1 MHz capacitance and dissipation. Two-tone intermodulation distortion products were measured and the third-order intercept is referenced to the microwave voltage across the capacitors. Commercially available semiconductor varactors were tested in a similar manner. The tuning quality (the ratio of the relative capacitance tuning to dissipation), frequency dispersion, and power handling of these capacitors are compared. Although there appears to be no intrinsic power handling advantage of the paraelectrics over the semiconductor varactors, the paraelectric varactors can offer better tuning quality.

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