The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Jiangtao Zhou - One of the best experts on this subject based on the ideXlab platform.
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fiber interface directional Coupler inscribed by femtosecond laser for refractive index measurements
Optics Express, 2020Co-Authors: Jinli Han, Yunfang Zhang, Changrui Liao, Yuying Jiang, Ying Wang, Chupao Lin, Shen Liu, Jiachen Wang, Zhe Zhang, Jiangtao ZhouAbstract:A novel fiber-interface directional waveguide Coupler was inscribed on the surface of a coreless fiber by femtosecond laser, and was successfully applied to highly sensitive refractive index (RI) measurements. The primary arm was first inscribed to couple light from a lead-in single mode fiber to the fiber interface, then back to a lead-out single mode fiber. A side arm was inscribed parallel and in close proximity to the primary arm. Light propagating in the primary arm could then be efficiently coupled into the side arm when a phase-matching condition was met, which produced a dramatic spectral dip at the coupling wavelength. The proposed device achieved a sensitivity as high as ∼8249 nm/RIU over an RI range of 1.44-1.45, due to strong evanescent fields excited in fiber-interface waveguides. The proposed in-fiber directional Coupler exhibits high mechanical strength, a compact configuration, and excellent RI sensitivity. As such, it has significant potential for practical applications in biochemical sensing.
K. H. Chan - One of the best experts on this subject based on the ideXlab platform.
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single layer microstrip high directivity coupled line Coupler with tight coupling
IEEE Transactions on Microwave Theory and Techniques, 2013Co-Authors: Yongle Wu, S W Leung, Yinliang Diao, K. H. ChanAbstract:A novel symmetrical coupled-line circuit structure without patterned ground plane is proposed to design tight-coupling high-directivity Couplers, which would be found in numerous applications in a microstrip RF front end because of its simple structure and inherent excellent compatibility. Based on a traditional even- and odd-mode technique, closed-form mathematical equations for both circuit electrical parameters and scattering parameters are obtained. Due to the use of two coupled-line sections placed in the vertical direction, the directivity of this novel Coupler without any other compensation techniques can be enhanced while maintaining tight-coupling performance of almost 3 dB. For demonstrative purposes, three typical full-wave simulation examples with realized physical dimensions in microstrip technology are presented, indicating high directivity and tight coupling coefficient. Finally, a practical microstrip coupled-line Coupler is designed and fabricated to operate at approximately 2 GHz. The measured results show good return loss, quadrature phase characteristics, high directivity, and strong coupling performances.
Jinli Han - One of the best experts on this subject based on the ideXlab platform.
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fiber interface directional Coupler inscribed by femtosecond laser for refractive index measurements
Optics Express, 2020Co-Authors: Jinli Han, Yunfang Zhang, Changrui Liao, Yuying Jiang, Ying Wang, Chupao Lin, Shen Liu, Jiachen Wang, Zhe Zhang, Jiangtao ZhouAbstract:A novel fiber-interface directional waveguide Coupler was inscribed on the surface of a coreless fiber by femtosecond laser, and was successfully applied to highly sensitive refractive index (RI) measurements. The primary arm was first inscribed to couple light from a lead-in single mode fiber to the fiber interface, then back to a lead-out single mode fiber. A side arm was inscribed parallel and in close proximity to the primary arm. Light propagating in the primary arm could then be efficiently coupled into the side arm when a phase-matching condition was met, which produced a dramatic spectral dip at the coupling wavelength. The proposed device achieved a sensitivity as high as ∼8249 nm/RIU over an RI range of 1.44-1.45, due to strong evanescent fields excited in fiber-interface waveguides. The proposed in-fiber directional Coupler exhibits high mechanical strength, a compact configuration, and excellent RI sensitivity. As such, it has significant potential for practical applications in biochemical sensing.
Yongle Wu - One of the best experts on this subject based on the ideXlab platform.
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single layer microstrip high directivity coupled line Coupler with tight coupling
IEEE Transactions on Microwave Theory and Techniques, 2013Co-Authors: Yongle Wu, S W Leung, Yinliang Diao, K. H. ChanAbstract:A novel symmetrical coupled-line circuit structure without patterned ground plane is proposed to design tight-coupling high-directivity Couplers, which would be found in numerous applications in a microstrip RF front end because of its simple structure and inherent excellent compatibility. Based on a traditional even- and odd-mode technique, closed-form mathematical equations for both circuit electrical parameters and scattering parameters are obtained. Due to the use of two coupled-line sections placed in the vertical direction, the directivity of this novel Coupler without any other compensation techniques can be enhanced while maintaining tight-coupling performance of almost 3 dB. For demonstrative purposes, three typical full-wave simulation examples with realized physical dimensions in microstrip technology are presented, indicating high directivity and tight coupling coefficient. Finally, a practical microstrip coupled-line Coupler is designed and fabricated to operate at approximately 2 GHz. The measured results show good return loss, quadrature phase characteristics, high directivity, and strong coupling performances.
Slawomir Gruszczynski - One of the best experts on this subject based on the ideXlab platform.
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Wideband Three-Section Symmetrical Coupled-Line Directional Coupler Operating in Differential Mode
IEEE Microwave and Wireless Components Letters, 2018Co-Authors: Ilona Piekarz, Konrad Janisz, Krzysztof Wincza, Jakub Sorocki, Slawomir GruszczynskiAbstract:In this letter, a concept of wideband multisection symmetrical coupled-line directional Couplers operating in a differential mode has been presented for the first time. The required different coupling coefficients for each of the coupled-line sections have been achieved by introducing a multilayer dielectric structure and by placing sections on different metallization layers. The theoretical investigation has been supported by measurements of an exemplary three-section symmetrical 3-dB coupled-line directional Coupler operating in a differential mode at the center frequency of f0 = 3 GHz.
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method for the design of low loss suspended stripline directional Couplers with equalized inductive and capacitive coupling coefficients
Microwave and Optical Technology Letters, 2009Co-Authors: Krzysztof Wincza, Slawomir GruszczynskiAbstract:Design of directional Couplers in an inhomogeneous suspended stripline dielectric structure has been comprehensively investigated. A new design procedure of coupled-line directional Couplers has been proposed in which the equalization of inductive and capacitive coupling coefficients is achieved simultaneously with matching to the desired characteristic impedance and, therefore, the conditions of ideal Coupler realization can be approached. To achieve that, a method of modification of the capacitive coupling coefficient in which shunt capacitances are added to coupled lines has been used. The proposed design procedure has been successfully applied to the design of a 3-dB directional Coupler. Results of both calculations and measurements are presented. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 315–319, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24035
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compact broadband butler matrix in multilayer technology for integrated multibeam antennas
Electronics Letters, 2007Co-Authors: Slawomir Gruszczynski, Krzysztof Wincza, K SachseAbstract:A compact broadband low-loss 4×4 Butler matrix is presented, for the first time in multilayer asymmetric technology. A coupled-line 3 dB compensated microstrip multilayer directional Coupler is utilised as a basic element of the Butler matrix. Excellent performance is achieved over one-octave frequency band in terms of amplitude and phase responses. A tandem connection of two 3 dB directional Couplers with reference lines is used as a crossover of transmission lines giving, additionally, the needed broadband 45° phase shift; moreover, no interlayer connections are necessary. The network can be easily applied in integrated planar and conformal multibeam antenna arrays as a surface mount element.
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design of compensated coupled stripline 3 db directional Couplers phase shifters and magic t s part ii broadband coupled line circuits
IEEE Transactions on Microwave Theory and Techniques, 2006Co-Authors: Slawomir Gruszczynski, Krzysztof Wincza, K SachseAbstract:The problem of discontinuities in broadband multisection coupled-stripline 3-dB directional Couplers, phase shifters, high-pass tapered-line 3-dB directional Couplers, and magic-T's, regarding the connections of coupled and terminating signal lines, is comprehensively investigated in this paper for the first time. The equivalent circuit of these discontinuities proposed in Part I has been used for accurate modeling of the broadband multisection and ultra-broadband high-pass coupled-stripline circuits. It has been shown that parasitic reactances, which result from the connections of signal and coupled lines, severely deteriorate the return losses and the isolation of such circuits and also-in case of tapered-line directional Couplers-the coupling responses. Moreover, it has been proven theoretically and experimentally that these discontinuity effects can be substantially reduced by introducing compensating shunt capacitances in a number of cross sections of coupled and signal lines. Results of measurements carried out for various designed and manufactured coupled-line circuits have been very promising and have proven the efficiency of the proposed broadband compensation technique. The theoretical and measured data are given for the following coupled-stripline circuits: a decade-bandwidth asymmetric three-section 3-dB directional Coupler, a decade-bandwidth three-section phase-shifter compensator, and a high-pass asymmetric tapered-line 3-dB Coupler
