scholarly journals Unusual Response of Thin LiTaO3 Films to Intense Microwave Pulses

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3588
Author(s):  
Haojia Chen ◽  
Qiong Gao ◽  
Baoliang Qian ◽  
Lishan Zhao
Keyword(s):  
Nonlinear Behaviour ◽  
Small Signal ◽  
Large Signal ◽  
Signal Model ◽  
Small Signal Model ◽  
Wide Range ◽  
Microwave Pulses ◽  
Intense Fields ◽  
Voltage Signal ◽  
Wave Sensors

Fundamentally different responses of a LiTaO 3 thin film detector are observed when it is subjected to short microwave pulses as the pulse intensity is altered over a wide range. We start from weak microwave pulses which lead to only trivial pyroelectric peak response. However, when the microwave pulses become intense, the normally expected pyroelectric signal seems to be suppressed and the sign of the voltage signal can even be completely changed. Analysis indicates that while the traditional pyroelectric model, which is a linear model and works fine for our data in the small regime, it does not work anymore in the large signal regime. Since the small-signal model is the key foundation of electromagnetic-wave sensors based on pyroelectric effects, such as pyroelectric infrared detecters, the observation in this work suggests that one should be cautious when using these devices in intense fields. In addition, the evolution of detector signal with respect to excitation strength suggests that the main polarisation process is changed in the large signal regime. This is of fundamental importance to the understanding on how crystalline solids interact with intense microwaves. Possible causes of the nonlinear behaviour is discussed.

Small- and large-signal modeling of InP HBTs in transferred-substrate technology

2014 ◽  
Vol 6 (3-4) ◽  
pp. 243-251 ◽  
Author(s):  
Tom K. Johansen ◽  
Matthias Rudolph ◽  
Thomas Jensen ◽  
Tomas Kraemer ◽  
Nils Weimann ◽  
...  
Keyword(s):  
Millimeter Wave ◽  
Parameter Extraction ◽  
Small Signal ◽  
Current Crowding ◽  
Signal Modeling ◽  
Large Signal ◽  
Signal Model ◽  
Small Signal Model ◽  
Starting Point ◽  
Equivalent Circuit Parameters

In this paper, the small- and large-signal modeling of InP heterojunction bipolar transistors (HBTs) in transferred substrate (TS) technology is investigated. The small-signal equivalent circuit parameters for TS-HBTs in two-terminal and three-terminal configurations are determined by employing a direct parameter extraction methodology dedicated to III–V based HBTs. It is shown that the modeling of measured S-parameters can be improved in the millimeter-wave frequency range by augmenting the small-signal model with a description of AC current crowding. The extracted elements of the small-signal model structure are employed as a starting point for the extraction of a large-signal model. The developed large-signal model for the TS-HBTs accurately predicts the DC over temperature and small-signal performance over bias as well as the large-signal performance at millimeter-wave frequencies.

scholarly journals Small-signal analysis of a single-stage bridgeless boost half-bridge AC/DC converter with bidirectional switch

2021 ◽  
Vol 12 (4) ◽  
pp. 2358
Author(s):  
Mohamad Affan Bin Mohd Noh ◽  
Mohd Rodhi Bin Sahid ◽  
Thang Ka Fei ◽  
Ravi Lakshmanan
Keyword(s):  
Steady State ◽  
Signal Analysis ◽  
Circuit Simulation ◽  
Single Stage ◽  
Small Signal ◽  
Large Signal ◽  
Signal Model ◽  
Matlab Simulink ◽  
Small Signal Analysis ◽  
Small Signal Model

A small-signal analysis of a single-stage bridgeless boost half-bridge alternating current/direct current (AC/DC) Converter with bidirectional switches is performed using circuit averaging method. The comprehensive approach to develop the small signal model from the steady state analysis is discussed. The small-signal model is then simulated with MATLAB Simulink. The small-signal model is verified through the comparison of the bode-plot obtained from MATLAB Simulink and the simulated large signal model in piecewise linear electrical circuit simulation (PLECS). The mathematical model obtain from the small-signal analysis is then used to determine the proportional gain K_p and integral gain K_i. In addition, the switch large-signal model is developed by considering the current and voltage waveforms during load transients and steady-state conditions.

A Modeling and Analysis of Push-Pull Forward Topology

2010 ◽  
Vol 40-41 ◽  
pp. 293-297
Author(s):  
Dian Li Hou ◽  
Qing Fan Zhang
Keyword(s):  
Averaging Method ◽  
Circuit Model ◽  
Small Signal ◽  
Large Signal ◽  
Signal Model ◽  
Modeling And Analysis ◽  
Leakage Inductance ◽  
Small Signal Model ◽  
Conduction Mode ◽  
Continuous Conduction Mode

By circuit averaging method, a small-signal model is derived from push-pull forward topology which works in Continuous Conduction Mode (CCM). Dynamic large-signal model, DC circuit model and small-signal model are derived. The effect of leakage inductance on push-pull forward topology is analyzed and simulated in detail.

Large-signal modeling of large-size GaN HEMTs with a comprehensive extrinsic elements extraction algorithm

2010 ◽  
Vol 2 (1) ◽  
pp. 63-73 ◽  
Author(s):  
J. Alberto Zamudio-Flores ◽  
Samir Dahmani ◽  
Günter Kompa
Keyword(s):  
Model Verification ◽  
Small Signal ◽  
Signal Modeling ◽  
Large Signal ◽  
Signal Model ◽  
Gate Width ◽  
Small Signal Model ◽  
Pulsed Dc ◽  
Extraction Algorithm ◽  
Gan Hemts

This work presents a measurement-based physics-oriented large-signal modeling technique for GaN HEMTs. All the model elements are derived directly from pulsed-DC measurements and bias dependent small-signal model elements. The proposed small-signal model features a 12-element extrinsic network, which allows proper modeling of the complex parasitic effects present in large gate-width devices. A reliable generally applicable extrinsic extraction algorithm is presented. It is based on pinch-off S-parameter measurements and on a scanning procedure to find the optimal capacitance distribution. Results of applying the algorithm with measured data of a GaN HEMT with gate width of 3.2-mm prove the consistency of the formulation. Successful model verification is shown under pulsed-DC, single- and two-tone operations, showing accurate predictions versus measurements of IDS, Pout, gain, harmonics and IMD products.

A small-signal model of a solar cell

SIMULATION ◽  
2014 ◽  
Vol 90 (11) ◽  
pp. 1231-1243 ◽  
Author(s):  
Miona Andrejević Stošović ◽  
Ivan Litovski ◽  
Duško Lukač ◽  
Marko Dimitrijević ◽  
Vančo Litovski
Keyword(s):  
Solar Cell ◽  
Switching Frequency ◽  
Small Signal ◽  
Large Signal ◽  
Signal Model ◽  
Photovoltaic Panel ◽  
Point Tracking ◽  
Power Point Tracking ◽  
Small Signal Model ◽  
Power Point

Starting with the experience that the output voltage and the output current of a photovoltaic panel are not pure direct current constants due to the inevitable connection to a converter (or inverter) that is working as a switching system, we came to the conclusion that interest exists for the behavior of the solar cell at the frequencies of the harmonics of the converter’s switching frequency, which is subject to change according to the maximum power-point tracking. In other words, a need exists for frequency domain characterization of the solar cell, for which a linear small-signal model is necessary. To enable simulation for small signals, development of a linear reactive model was considered. Since a one-diode large-signal model already exists, it was used as a basis for the extraction of the parameters of the small-signal model. The new model was represented in the form of a parallel RC two-terminal circuit, the R and C being functions of the photocurrent (acting as a map of the illumination) and the diode voltage. Since the R and C of the model are quiescent-point dependent, their values as a function of the illumination and the diode voltages were approximated by artificial neural networks (ANNs). Separate ANNs were created for modeling R and C. To verify the model, two small-signal simulations were performed. The first one was done with the existing nonlinear model, while the second was done with the new linear model (running the ANNs). Excellent agreement was obtained.

MESFET large-signal model based on small-signal measurements for time-domain CAD

1988 ◽  
Vol 24 (15) ◽  
pp. 973 ◽  
Author(s):  
A. Ouslimani ◽  
G. Vernet ◽  
J.C. Henaux ◽  
P. Crozat ◽  
R. Adde
Keyword(s):  
Time Domain ◽  
Small Signal ◽  
Large Signal ◽  
Signal Model ◽  
Model Based
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