"High frequency" I-V curves for GaAs MESFETs through unique determination of small signal circuit parameters at multiple bias points

2002 ◽  
Author(s):  
C.C. Meng ◽  
G.H. Huang
Keyword(s):  
High Frequency ◽  
Unique Determination ◽  
Small Signal

ANOMALOUS FREQUENCY DEPENDENCE OF DIFFERENTIAL MOBILITY IN SUPERLATTICE MINIBAND TRANSPORT

1996 ◽  
Vol 10 (01n02) ◽  
pp. 51-60
Author(s):  
X.L. LEI ◽  
N.J.M. HORING ◽  
H.L. CUI ◽  
K.K. THORNBER
Keyword(s):  
Frequency Dependence ◽  
High Frequency ◽  
Small Signal ◽  
Differential Mobility ◽  
Unusual Behavior ◽  
Velocity Overshoot ◽  
Ac Electric Field ◽  
Dc Bias ◽  
Miniband Transport

We examine the frequency-dependence of carrier drift-velocity in superlattice miniband conduction for a small signal ac electric field superposed on a dc bias E0. Our determination of the differential mobility is based on an accurate microscopic treatment of phonon and impurity scatterings. At finite E0, the differential mobility exhibits anomalous frequency-dependence: its real part exhibits a broad hump before finally approaching zero at high frequency, and its imaginary part has a marked dip to negative values before going through the conventional maximum. A simple dual-parameter empirical formula adapted from velocity overshoot studies provides excellent fits to this unusual behavior.

Magnetic Permeability and Relaxation Frequency in High Frequency Magnetic Materials.

2001 ◽  
Vol 674 ◽  
Author(s):  
M.I. Rosales ◽  
H. Montiel ◽  
R. Valenzuela
Keyword(s):  
High Frequency ◽  
Domain Walls ◽  
Magnetocrystalline Anisotropy ◽  
Low Frequency ◽  
Frequency Dispersion ◽  
Anisotropy Constant ◽  
Relaxation Frequency ◽  
Resonance Relaxation ◽  
Frequency Behavior

ABSTRACTAn investigation of the frequency behavior of polycrystalline ferrites is presented. It is shown that the low frequency dispersion (f < 10 MHz) of permeability is associated with the bulging of pinned domain walls, and has a mixed resonance-relaxation character, closer to the latter. It is also shown that there is a linear relationship between the magnetocrystalline anisotropy constant, K1, and the relaxation frequency. The slope of this correlation depends on the grain size. Such a relationship could allow the determination of this basic parameter from polycrystalline samples.

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