Theoretical analysis of the minimization of thermal effects on the coupling length of directional couplers

2011 ◽  
Author(s):  
J. J. Isidio-Lima ◽  
V. F. Rodriguez-Esquerre ◽  
Bernardo Yugi-Dantas
Keyword(s):  
Theoretical Analysis ◽  
Thermal Effects ◽  
Coupling Length ◽  
Directional Couplers

A Thermal Hydrodynamic Lubrication Theory for Hydrostatic Extrusion of Low Strength Materials

1976 ◽  
Vol 98 (2) ◽  
pp. 335-342 ◽  
Author(s):  
R. W. Snidle ◽  
B. Parsons ◽  
D. Dowson
Keyword(s):  
Plastic Deformation ◽  
Theoretical Analysis ◽  
Thermal Effects ◽  
Hydrodynamic Lubrication ◽  
Extrusion Process ◽  
Lubrication Theory ◽  
Lubricant Film ◽  
Hydrostatic Extrusion ◽  
Solid Friction ◽  
Hydrodynamic Lubrication Theory

The paper presents a theoretical analysis of hydrodynamic lubrication in the hydrostatic extrusion process which includes a consideration of thermal effects in the lubricant film arising from the work of plastic deformation. A Newtonian lubricant with an exponential pressure-temperature-viscosity relationship has been assumed and allowance has been made for the effects of redundant deformation of the worked material. The results of the theory are compared with those from previous isothermal and solid friction theories.

Theoretical analysis of the thermal effects during in vivo tissue electroporation

2003 ◽  
Vol 61 (1-2) ◽  
pp. 99-107 ◽  
Author(s):  
Rafael V. Davalos ◽  
Boris Rubinsky ◽  
Lluis M. Mir
Keyword(s):  
Theoretical Analysis ◽  
Thermal Effects ◽  
Tissue Electroporation

Broadband coupled-line directional couplers with high impedance transformation ratio

2017 ◽  
Vol 9 (7) ◽  
pp. 1473-1480
Author(s):  
Krzysztof Wincza ◽  
Slawomir Gruszczynski
Keyword(s):  
Theoretical Analysis ◽  
Frequency Range ◽  
Directional Couplers ◽  
Coupled Line ◽  
New Class ◽  
High Impedance ◽  
Transformation Ratio ◽  
Limiting Condition

A new class of 3-dB impedance transforming directional couplers has been proposed in which the recently published coupled-line couplers, consisting of coupled-line sections having different electrical lengths, have been utilized. The main advantage of the proposed directional couplers is the possibility of obtaining high impedance transformation ratio, thus the known limiting condition of realizable impedance transformation in 3-dB couplers is overcome. Moreover, the proposed directional couplers feature significantly wider operational bandwidths. The theoretical analysis of the proposed impedance-transforming directional couplers has been shown and is fully supported by the measurements of the manufactured model operating in 0.5–1.5 GHz frequency range.

Application of RH and LH sections for reduction of coupling coefficients in two-section asymmetric directional couplers

2015 ◽  
Vol 8 (3) ◽  
pp. 559-565 ◽  
Author(s):  
Jakub Sorocki ◽  
Kamil Staszek ◽  
Ilona Piekarz ◽  
Krzysztof Wincza ◽  
Slawomir Gruszczynski
Keyword(s):  
Theoretical Analysis ◽  
Transmission Lines ◽  
Directional Coupler ◽  
Center Frequency ◽  
Coupling Coefficients ◽  
Directional Couplers ◽  
Coupled Line ◽  
Left Handed ◽  
Design Flexibility

A method allowing for reduction of coupling coefficients required for realization of two-section asymmetrical coupled-line directional couplers has been proposed. It has been shown that by connecting uncoupled left-handed and right-handed transmission lines between two coupled-line sections one can obtain greater design flexibility of the resulting circuit, simultaneously with the coupling reduction in coupled-line sections. Moreover, the proposed circuit features the properties of two-section asymmetric directional couplers offering wide operational bandwidth. The theoretical analysis has been verified by measurements of a 3 dB directional coupler operating at the center frequency f0 = 1.5 GHz having coupling imbalance δC = ±0.4 dB and bandwidth 0.75–2.3 GHz.

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