Estimation of high frequency scattered microwave electric field using the extended Born approximation [microwave imaging applications]

2004 ◽  
Author(s):  
Yang Yang ◽  
O.A. Basir ◽  
Yaxun Liu
Keyword(s):  
Electric Field ◽  
Born Approximation ◽  
High Frequency ◽  
Microwave Imaging

Formation of Regular Domain Structures in Quenched Ferroelectrics Under the Influence of an External High-frequency Electric Field

2019 ◽  
Vol 9 (3) ◽  
pp. 344-352 ◽  
Author(s):  
L.I. Stefanovich ◽  
O.Y. Mazur ◽  
V.V. Sobolev
Keyword(s):  
Lithium Niobate ◽  
Electric Field ◽  
Domain Structure ◽  
High Frequency ◽  
Evolution Equations ◽  
Regular Domain ◽  
Field Frequency ◽  
Domain Structures ◽  
Alternating Electric Field ◽  
Lithium Niobate Crystals

Introduction: Within the framework of the phenomenological theory of phase transitions of the second kind of Ginzburg-Landau, the kinetics of ordering of a rapidly quenched highly nonequilibrium domain structure is considered using the lithium tantalate and lithium niobate crystals as an example. Experimental: Using the statistical approach, evolution equations describing the formation of the domain structure under the influence of a high-frequency alternating electric field in the form of a standing wave were obtained. Numerical analysis has shown the possibility of forming thermodynamically stable mono- and polydomain structures. It turned out that the process of relaxation of the system to the state of thermodynamic equilibrium can proceed directly or with the formation of intermediate quasi-stationary polydomain asymmetric phases. Results: It is shown that the formation of Regular Domain Structures (RDS) is of a threshold character and occurs under the influence of an alternating electric field with an amplitude less than the critical value, whose value depends on the field frequency. The conditions for the formation of RDSs with a micrometer spatial scale were determined. Conclusion: As shown by numerical studies, the RDSs obtained retain their stability, i.e. do not disappear even after turning off the external electric field. Qualitative analysis using lithium niobate crystals as an example has shown the possibility of RDSs formation in high-frequency fields with small amplitude under resonance conditions

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