This paper reports a novel dual-band coupled-line bandpass filter.Comprising a quadruple-mode coupled-line resonator,this proposed filter could filter signals on two frequency bands.After introducing two varactors,one...This paper reports a novel dual-band coupled-line bandpass filter.Comprising a quadruple-mode coupled-line resonator,this proposed filter could filter signals on two frequency bands.After introducing two varactors,one of the four resonances could be continuously altered by changing the capacitance of the varactors,thus the two frequency bandwidths could be independently tunned.In this paper,the detailed explanation for its operation is given,and the agreement between the expected and practical performance sufficiently confirms the robustness and effectiveness of this proposed filter.展开更多
A dual structure of composite right/left handed (CRLH) transmission line (TL) is analyzed in which an inductance LR is in parallel with a capacitance CL and a shunt capacitance CR is in series with an inductance LL. B...A dual structure of composite right/left handed (CRLH) transmission line (TL) is analyzed in which an inductance LR is in parallel with a capacitance CL and a shunt capacitance CR is in series with an inductance LL. Both the distributed and lumped cases are considered. The dispersion diagram and transmission properties of the dual CRLH TL are given and compared with those of a standard CRLH TL. Contrary to the frequency response of a standard CRLH TL, a dual CRLH TL has a left-handed (negative phase shift) band at higher frequencies and a right-handed (positive phase shift) band at lower frequencies. A novel dual-band balun is presented as an application.展开更多
A long-lived and loosely organized squall line moved rapidly across U¨ru¨mqi, the capital city of Xinjiang Uygur Autonomous Region of China on 26 June 2005, generating hail and strong winds. The squall line ...A long-lived and loosely organized squall line moved rapidly across U¨ru¨mqi, the capital city of Xinjiang Uygur Autonomous Region of China on 26 June 2005, generating hail and strong winds. The squall line was observed by a dual Doppler radar system in a field experiment conducted in 2004 and 2005 by the Chinese Academy of Meteorological Sciences and the local meteorological bureau in northwestern China. The 3D wind fields within the squall line were retrieved through dual Doppler analyses and a variational Doppler radar analysis system （VDRAS）. The formation and structure of the squall line as well as the genesis and evolution of embedded convective cells were investigated. During its life period, the squall line consisted of six storm cells extending about 100 km in length, and produced hail of about 25 mm in diameter and strong surface winds up to 11 m s^-1. Radar observations revealed a broad region of stratiform rain in a meso-β cyclone, with the squall line located to the west of this. Two meso-γ scale vortices were found within the squall line. Compared to typical squall lines in moist regions, such as Guangdong Province and Shanghai, which tend to be around 300–400 km in length, have echo tops of 17–19 km, and produce maximum surface winds of about 25 m s^-1 and temperature variations of about 8-C this squall line system had weaker maximum reflectivity （55 dBZ）, a lower echo top （13 km） and smaller extension （about 100 km）, relatively little stratiform rainfall preceding the convective line, and a similar moving speed and temperature variation at the surface.展开更多
A planar circuit structure, which is based on three cascaded pairs of coupled lines, an open stub, and an isolation resistor, is proposed in this paper to design a compact dual.band balun with high isolation. This cir...A planar circuit structure, which is based on three cascaded pairs of coupled lines, an open stub, and an isolation resistor, is proposed in this paper to design a compact dual.band balun with high isolation. This circuit features equal power division with out of phase, all ports matching, high isolation between two outputs, compact structure, and inherent impedance transformation. The closedform design equations are derived based on the traditional transmission.line theory and even.(odd.) mode analysis. A practical dual.band balun, which operates at 0.9/1.8GHz, is designed and fabricated to validate the function of equal power division with out of phase and high isolation between two outputs. The consistency between the simulated and measured results verify the design theory.展开更多
This paper presents a concurrent dual-band branch-line coupler with an independently tunable center frequency. In the proposed architecture, the quarter-wavelength lines, which work at two separated bands concurrently...This paper presents a concurrent dual-band branch-line coupler with an independently tunable center frequency. In the proposed architecture, the quarter-wavelength lines, which work at two separated bands concurrently and can be tuned in one of them, are key components. Based on the analysis of ABCD-matrix, a novel hybrid structure and a pair of varactors topology are utilized to achieve concurrent dual-band operation and independent tunability, respectively. Using this configuration, it is convenient to tune the center frequency of the upper band, while the responses of the lower band remain unaltered. To verify the proposed idea, a demonstration is implemented and the simulated results are presented.展开更多
To realize equal power splitting at two arbitrary gigahertz-frequencies, this paper presents a new type of Wilkinson dual frequency power divider, consisting of three-section transmission lines and a series RLC(resist...To realize equal power splitting at two arbitrary gigahertz-frequencies, this paper presents a new type of Wilkinson dual frequency power divider, consisting of three-section transmission lines and a series RLC(resistor, inductor and capacitor)circuit. By equating the [ABCD] matrix of the proposed circuit to that of the quarter-wave impedance transformer, coupled with even/odd mode analyses, the design equations of the proposed network are derived. For verification, two dual-frequency power dividers with dual-band operating frequencies at 0.6 GHz and 3.0 GHz, and 3.8 GHz and 10 GHz respectively are designed and simulated. Simulation results show that the dual-band ratio of the proposed power divider can be as large as 5. Comparisons of the simulation results at X-band and S-band with different power dividers indicate that the proposed dual-band power divider performs better under the scenario of the upper operating frequency extending to X-band.展开更多
A tunable dual-broad-band branch-line coupler (BLC) utilizing composite right/left-handed (CRLH) transmission lines is presented. Two λ/4 segments consisting of CRLH transmission lines are added to each port to broad...A tunable dual-broad-band branch-line coupler (BLC) utilizing composite right/left-handed (CRLH) transmission lines is presented. Two λ/4 segments consisting of CRLH transmission lines are added to each port to broaden the dual bands of the branch-line coupler. Numerical simulation and optimal design of the novel coupler are presented. The dual bands of the novel coupler are tunable and broad. The 1-dB bandwidth of each pass band is more than 16% of the central frequency.展开更多
基金supported by National Basic Research Program of China(973 Program)(No.2014CB339900)National Natural Science Foundations of China(No.61422103,and 61327806)
文摘This paper reports a novel dual-band coupled-line bandpass filter.Comprising a quadruple-mode coupled-line resonator,this proposed filter could filter signals on two frequency bands.After introducing two varactors,one of the four resonances could be continuously altered by changing the capacitance of the varactors,thus the two frequency bandwidths could be independently tunned.In this paper,the detailed explanation for its operation is given,and the agreement between the expected and practical performance sufficiently confirms the robustness and effectiveness of this proposed filter.
基金Project supported by the National Basic Research Program (973) of China (No. 2004CB719802), and the Science and Technology De-partment of Zhejiang Province (No. 2005C31004), China
文摘A dual structure of composite right/left handed (CRLH) transmission line (TL) is analyzed in which an inductance LR is in parallel with a capacitance CL and a shunt capacitance CR is in series with an inductance LL. Both the distributed and lumped cases are considered. The dispersion diagram and transmission properties of the dual CRLH TL are given and compared with those of a standard CRLH TL. Contrary to the frequency response of a standard CRLH TL, a dual CRLH TL has a left-handed (negative phase shift) band at higher frequencies and a right-handed (positive phase shift) band at lower frequencies. A novel dual-band balun is presented as an application.
基金funded by the Na-tional Natural Science Foundation of China (Grant No.40375008)
文摘A long-lived and loosely organized squall line moved rapidly across U¨ru¨mqi, the capital city of Xinjiang Uygur Autonomous Region of China on 26 June 2005, generating hail and strong winds. The squall line was observed by a dual Doppler radar system in a field experiment conducted in 2004 and 2005 by the Chinese Academy of Meteorological Sciences and the local meteorological bureau in northwestern China. The 3D wind fields within the squall line were retrieved through dual Doppler analyses and a variational Doppler radar analysis system （VDRAS）. The formation and structure of the squall line as well as the genesis and evolution of embedded convective cells were investigated. During its life period, the squall line consisted of six storm cells extending about 100 km in length, and produced hail of about 25 mm in diameter and strong surface winds up to 11 m s^-1. Radar observations revealed a broad region of stratiform rain in a meso-β cyclone, with the squall line located to the west of this. Two meso-γ scale vortices were found within the squall line. Compared to typical squall lines in moist regions, such as Guangdong Province and Shanghai, which tend to be around 300–400 km in length, have echo tops of 17–19 km, and produce maximum surface winds of about 25 m s^-1 and temperature variations of about 8-C this squall line system had weaker maximum reflectivity （55 dBZ）, a lower echo top （13 km） and smaller extension （about 100 km）, relatively little stratiform rainfall preceding the convective line, and a similar moving speed and temperature variation at the surface.
基金supported by National Natural Science Foundations of China (No.61422103, and No.61671084)National Key Basic Research Program of China (973 Program) (No.2014CB339900)BUPT Excellent Ph.D. Students Foundation (CX2016303)
文摘A planar circuit structure, which is based on three cascaded pairs of coupled lines, an open stub, and an isolation resistor, is proposed in this paper to design a compact dual.band balun with high isolation. This circuit features equal power division with out of phase, all ports matching, high isolation between two outputs, compact structure, and inherent impedance transformation. The closedform design equations are derived based on the traditional transmission.line theory and even.(odd.) mode analysis. A practical dual.band balun, which operates at 0.9/1.8GHz, is designed and fabricated to validate the function of equal power division with out of phase and high isolation between two outputs. The consistency between the simulated and measured results verify the design theory.
基金Supported by the Provincial Natural Science Foundation of Zhejiang(No.Y1101270)the National Natural Science Foundation of China(No.61171040)+1 种基金Ningbo University Disciplinary Project(No.XKL141038)Agilent Technologies Inc.Research Project(No.3110)
文摘This paper presents a concurrent dual-band branch-line coupler with an independently tunable center frequency. In the proposed architecture, the quarter-wavelength lines, which work at two separated bands concurrently and can be tuned in one of them, are key components. Based on the analysis of ABCD-matrix, a novel hybrid structure and a pair of varactors topology are utilized to achieve concurrent dual-band operation and independent tunability, respectively. Using this configuration, it is convenient to tune the center frequency of the upper band, while the responses of the lower band remain unaltered. To verify the proposed idea, a demonstration is implemented and the simulated results are presented.
文摘To realize equal power splitting at two arbitrary gigahertz-frequencies, this paper presents a new type of Wilkinson dual frequency power divider, consisting of three-section transmission lines and a series RLC(resistor, inductor and capacitor)circuit. By equating the [ABCD] matrix of the proposed circuit to that of the quarter-wave impedance transformer, coupled with even/odd mode analyses, the design equations of the proposed network are derived. For verification, two dual-frequency power dividers with dual-band operating frequencies at 0.6 GHz and 3.0 GHz, and 3.8 GHz and 10 GHz respectively are designed and simulated. Simulation results show that the dual-band ratio of the proposed power divider can be as large as 5. Comparisons of the simulation results at X-band and S-band with different power dividers indicate that the proposed dual-band power divider performs better under the scenario of the upper operating frequency extending to X-band.
基金Project (No. 2004CB719802) supported by the National Basic Re-search Program (973) of China
文摘A tunable dual-broad-band branch-line coupler (BLC) utilizing composite right/left-handed (CRLH) transmission lines is presented. Two λ/4 segments consisting of CRLH transmission lines are added to each port to broaden the dual bands of the branch-line coupler. Numerical simulation and optimal design of the novel coupler are presented. The dual bands of the novel coupler are tunable and broad. The 1-dB bandwidth of each pass band is more than 16% of the central frequency.
