High frequency Losses Calculating Model for Magnetostrictive Materials Considering Variable DC Bias

2021 ◽  
pp. 1-1
Author(s):  
Pingping Guo ◽  
Wenmei Huang ◽  
Wanli Guo ◽  
Ling Weng
Keyword(s):  
High Frequency ◽  
Magnetostrictive Materials ◽  
Dc Bias ◽  
Calculating Model

scholarly journals Reliability Concerns due to Self-Heating effects in GaN HEMTs

2013 ◽  
Vol 8 (2) ◽  
pp. 78-82
Author(s):  
B. Padmanabhan ◽  
D. Vasileska ◽  
S. M. Goodnick
Keyword(s):  
High Power ◽  
High Frequency ◽  
Additional Problem ◽  
Bias Stress ◽  
Self Heating ◽  
Current Collapse ◽  
Heating Effects ◽  
Dc Bias ◽  
Gan Hemts

Current collapse phenomenon that occurs in GaN HEMTs under a moderately large DC bias stress, poses serious problems for usage of GaN technology in high-power high-frequency applications from a reliability standpoint. Additional problem in these devices operated at high biases is the appearance of self-heating effects that degrade device characteristics and, as shown in this work further amplify the problem of current collapse by changing the device electrostatics.

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.

Using High Frequency LIMM to characterize the poling state of piezoelectric ceramic thin films

2015 ◽  
Vol 1805 ◽  
Author(s):  
Mark Stewart ◽  
Markys G Cain
Keyword(s):  
Thin Films ◽  
High Frequency ◽  
Piezoelectric Ceramic ◽  
Laser Intensity ◽  
Polarization State ◽  
Intensity Modulation ◽  
Modulation Method ◽  
Piezoelectric Thin Films ◽  
Ceramic Thin Films ◽  
Dc Bias

ABSTRACTThe Laser Intensity Modulation Method, LIMM, has been used to investigate the poling state of ceramic piezoelectric thin films. The frequency of the system has been extended to 70MHz to enable films of thicknesses down to 100nm to be measured. A unique development has been to sweep the DC bias applied to the sample whilst performing the LIMM measurement, thus giving pseudo PE loops. These PE loops are unique in that they represent the polarization state within a distinct depth of the film, whereas normally PE loops are a result of the complete film. This allows us to investigate processes occurring within different regions of the film.

scholarly journals Electrostatically Tunable Nanomechanical Shallow Arches

2017 ◽  
Author(s):  
Syed N. R. Kazmi ◽  
Amal Z. Hajjaj ◽  
Pedro M. F. J. Costa ◽  
Mohammad I. Younis
Keyword(s):  
High Frequency ◽  
Room Temperature ◽  
Silicon On Insulator ◽  
Frequency Range ◽  
Shallow Arches ◽  
High Tunability ◽  
Band Pass ◽  
Dc Bias ◽  
Silicon Based ◽  
Good Agreement

We report an analytical and experimental study on the tunability of in-plane doubly-clamped nanomechanical arches under varied DC bias conditions at room temperature. For this purpose, silicon based shallow arches are fabricated using standard e-beam lithography and surface nanomachining of a highly conductive device layer on a silicon-on-insulator (SOI) wafer. The experimental results show good agreement with the analytical results with a maximum tunability of 108.14% for 180 nm thick arch with a transduction gap of 1 μm between the beam and the driving/sensing electrodes. The high tunability of shallow arches paves the ways for highly tunable band pass filtering applications in high frequency range.

Design of Energy-Saving Piezoelectric Actuator Drive for High Frequency Servo Valve

2014 ◽  
Vol 651-653 ◽  
pp. 957-961
Author(s):  
Wei Pan ◽  
Chang Hou Lu ◽  
Zi Chao Liu
Keyword(s):  
Energy Saving ◽  
High Frequency ◽  
Circuit Complexity ◽  
Equivalent Model ◽  
Reciprocating Motion ◽  
Simulation Experiments ◽  
Bias Power ◽  
Circuit Topology ◽  
Servo Valve ◽  
Dc Bias

The paper presents a circuit topology favorable to drive piezoelectric actuators for high frequency servo valve. It begins with a short overview of different energy-saving PZA drive types and their tradeoff between efficiency and circuit complexity. Then the mechanical structure and equivalent model of the piezoelectric servo valve are described. And the circuit topology including an energy-saving oscillator, an efficient DC bias power and a repetitive controller especially for tracking reciprocating motion, is proposed. The efficiency-improved PZA drive is then derived from the above design. Finally, the drive together with the servo valve is tested in the simulation experiments.

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