The Experts below are selected from a list of 48306 Experts worldwide ranked by ideXlab platform
Kai Chang - One of the best experts on this subject based on the ideXlab platform.
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compact low Insertion Loss sharp rejection and wide band microstrip bandpass filters
IEEE Transactions on Microwave Theory and Techniques, 2003Co-Authors: Lunghwa Hsieh, Kai ChangAbstract:This paper presents a new compact, low Insertion-Loss, sharp-rejection, and wide-band microstrip bandpass filter. A bandstop filter is introduced that uses a ring resonator with direct-connected orthogonal feed lines. A new bandpass filter based on the bandstop filter uses two tuning stubs to construct a wide-band passband with two sharp stopbands. Without coupling gaps between feed lines and rings, there are no mismatch and radiation Losses between them and, therefore, the new filters show low Insertion Loss. In addition, a dual-mode characteristic is used to increase the stopband bandwidth of the new filters. A simple transmission-line model used to calculate the frequency responses of the filters shows good agreement with measurements. The filter using three cascaded rings has 3-dB fractional bandwidth of 49.3%, an Insertion Loss of better than 1.6 dB in the passband, a return Loss of larger than 13 dB from 4.58 to 7.3 GHz, and two rejections of greater than 40 dB within 2.75-4.02 and 7.73-9.08 GHz. The high-performance, compact-size, and low-cost filter was designed for reducing the interference in full duplex systems in satellite communications.
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compact size and low Insertion Loss chebyshev function bandpass filters using dual mode patch resonators
Electronics Letters, 2001Co-Authors: Lunghwa Hsieh, Kai ChangAbstract:A compact Chebyshev-function bandpass filter using dual-mode patch resonators is proposed. The filter presents 75% size reduction compared with the conventional Chebyshev bandpass filter using two square patch resonators. Because of inset feeding and only one coupling gap being required, the new filters can achieve a low Insertion Loss of 1.1 dB and reduce the fabrication uncertainties.
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dual mode elliptic function bandpass filter using one single patch resonator without coupling gaps
Electronics Letters, 2000Co-Authors: Lunghwa Hsieh, Kai ChangAbstract:A novel dual-mode, compact, and simple elliptic-function bandpass filter structure without coupling gaps is proposed. This filter has Insertion Loss 10 dB within 2.3-2.375 GHz. Without coupling gaps between the feed lines and the patch resonator, the new filter can provide a low Insertion Loss and reduce uncertainty in fabrication.
Lunghwa Hsieh - One of the best experts on this subject based on the ideXlab platform.
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compact low Insertion Loss sharp rejection and wide band microstrip bandpass filters
IEEE Transactions on Microwave Theory and Techniques, 2003Co-Authors: Lunghwa Hsieh, Kai ChangAbstract:This paper presents a new compact, low Insertion-Loss, sharp-rejection, and wide-band microstrip bandpass filter. A bandstop filter is introduced that uses a ring resonator with direct-connected orthogonal feed lines. A new bandpass filter based on the bandstop filter uses two tuning stubs to construct a wide-band passband with two sharp stopbands. Without coupling gaps between feed lines and rings, there are no mismatch and radiation Losses between them and, therefore, the new filters show low Insertion Loss. In addition, a dual-mode characteristic is used to increase the stopband bandwidth of the new filters. A simple transmission-line model used to calculate the frequency responses of the filters shows good agreement with measurements. The filter using three cascaded rings has 3-dB fractional bandwidth of 49.3%, an Insertion Loss of better than 1.6 dB in the passband, a return Loss of larger than 13 dB from 4.58 to 7.3 GHz, and two rejections of greater than 40 dB within 2.75-4.02 and 7.73-9.08 GHz. The high-performance, compact-size, and low-cost filter was designed for reducing the interference in full duplex systems in satellite communications.
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compact low Insertion Loss sharp rejection wideband bandpass filters using dual mode ring resonators with tuning stubs
Electronics Letters, 2001Co-Authors: Lunghwa Hsieh, K ChangAbstract:Novel wideband bandpass filters using dual-mode ring resonators with orthogonal direct-connected feed lines and tuning stubs are developed. The tuning stubs act as series resonators and provide sharp rejections for the filters. Also, a perturbation stub in each ring influences the fields of the ring resonators and generates a dual mode to extend the stop bands of the filters. The simulated and measured results agree well. This novel bandpass filter has advantages of compact size, low Insertion Loss, and sharp rejection.
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compact size and low Insertion Loss chebyshev function bandpass filters using dual mode patch resonators
Electronics Letters, 2001Co-Authors: Lunghwa Hsieh, Kai ChangAbstract:A compact Chebyshev-function bandpass filter using dual-mode patch resonators is proposed. The filter presents 75% size reduction compared with the conventional Chebyshev bandpass filter using two square patch resonators. Because of inset feeding and only one coupling gap being required, the new filters can achieve a low Insertion Loss of 1.1 dB and reduce the fabrication uncertainties.
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dual mode elliptic function bandpass filter using one single patch resonator without coupling gaps
Electronics Letters, 2000Co-Authors: Lunghwa Hsieh, Kai ChangAbstract:A novel dual-mode, compact, and simple elliptic-function bandpass filter structure without coupling gaps is proposed. This filter has Insertion Loss 10 dB within 2.3-2.375 GHz. Without coupling gaps between the feed lines and the patch resonator, the new filter can provide a low Insertion Loss and reduce uncertainty in fabrication.
Shengfuh Chang - One of the best experts on this subject based on the ideXlab platform.
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a full 360 circ reflection type phase shifter with constant Insertion Loss
IEEE Microwave and Wireless Components Letters, 2008Co-Authors: Shengfuh Chang, Wenchun HsiaoAbstract:A new reflection-type phase shifter with a full 360deg relative phase shift range and constant Insertion Loss is presented. This feature is obtained by incorporating a new cascaded connection of varactors into the impedance-transforming quadrature coupler. The required reactance variation of a varactor can be reduced by controlling the impedance ratio of the quadrature coupler. The implemented phase shifter achieves a measured maximal relative phase shift of 407deg, an averaged Insertion Loss of 4.4 dB and return Losses better than 19 dB at 2 GHz. The Insertion-Loss variation is within plusmn0.1 and plusmn0.2 dB over the 360deg and 407deg relative phase shift tuning range, respectively.
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design of stepped impedance combline bandpass filters with symmetric Insertion Loss response and wide stopband range
IEEE Transactions on Microwave Theory and Techniques, 2007Co-Authors: Yiming Chen, Shengfuh Chang, Chiachan Chang, Tinjae HungAbstract:An enhanced stepped-impedance combline bandpass filter employs an array of stepped-impedance resonators with tapped-transformer coupling at input and output is presented in this study. This filter has enhanced performance, including symmetric Insertion-Loss response around the passband and wider stopband range. The structure is compact and suitable for multilayer realization because it is free of lumped capacitors and has fewer via-hole grounds. The circuit is investigated with the characteristic mode theory of coupled lines to prove the existence of multiple transmission zeros around the passband. Numerous diagrams are given for circuit design purposes. The second- and fourth-order bandpass filters at 2.45 GHz were designed, measured, and compared with the conventional combline structure to demonstrate their performance enhancement.
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design of a reflection type phase shifter with wide relative phase shift and constant Insertion Loss
IEEE Transactions on Microwave Theory and Techniques, 2007Co-Authors: Shengfuh Chang, Chiachan ChangAbstract:reflection-type phase shifter with constant Insertion Loss over a wide relative phase-shift range is presented. This important feature is attributed to the salient integration of an impedance-transforming quadrature coupler with equalized series-resonated varactors. The impedance-transforming quadrature coupler is used to increase the maximal relative phase shift for a given varactor with a limited capacitance range. When the phase is tuned, the typical large Insertion-Loss variation of the phase shifter due to the varactor parasitic effect is minimized by shunting the series-resonated varactor with a resistor Rp. A set of closed-form equations for predicting the relative phase shift, Insertion Loss, and Insertion-Loss variation with respect to the quadrature coupler and varactor parameters is derived. Three phase shifters were implemented with a silicon varactor of a restricted capacitance range of Cv,min = 1.4 pF and Cv,max = 8 pF, wherein the parasitic resistance is close to 2 Omega. The measured Insertion-Loss variation is 0.1 dB over the relative phase-shift tuning range of 237deg at 2 GHz and the return Losses are better than 20 dB, excellently agreeing with the theoretical and simulated results.
Chiachan Chang - One of the best experts on this subject based on the ideXlab platform.
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design of stepped impedance combline bandpass filters with symmetric Insertion Loss response and wide stopband range
IEEE Transactions on Microwave Theory and Techniques, 2007Co-Authors: Yiming Chen, Shengfuh Chang, Chiachan Chang, Tinjae HungAbstract:An enhanced stepped-impedance combline bandpass filter employs an array of stepped-impedance resonators with tapped-transformer coupling at input and output is presented in this study. This filter has enhanced performance, including symmetric Insertion-Loss response around the passband and wider stopband range. The structure is compact and suitable for multilayer realization because it is free of lumped capacitors and has fewer via-hole grounds. The circuit is investigated with the characteristic mode theory of coupled lines to prove the existence of multiple transmission zeros around the passband. Numerous diagrams are given for circuit design purposes. The second- and fourth-order bandpass filters at 2.45 GHz were designed, measured, and compared with the conventional combline structure to demonstrate their performance enhancement.
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design of a reflection type phase shifter with wide relative phase shift and constant Insertion Loss
IEEE Transactions on Microwave Theory and Techniques, 2007Co-Authors: Shengfuh Chang, Chiachan ChangAbstract:reflection-type phase shifter with constant Insertion Loss over a wide relative phase-shift range is presented. This important feature is attributed to the salient integration of an impedance-transforming quadrature coupler with equalized series-resonated varactors. The impedance-transforming quadrature coupler is used to increase the maximal relative phase shift for a given varactor with a limited capacitance range. When the phase is tuned, the typical large Insertion-Loss variation of the phase shifter due to the varactor parasitic effect is minimized by shunting the series-resonated varactor with a resistor Rp. A set of closed-form equations for predicting the relative phase shift, Insertion Loss, and Insertion-Loss variation with respect to the quadrature coupler and varactor parameters is derived. Three phase shifters were implemented with a silicon varactor of a restricted capacitance range of Cv,min = 1.4 pF and Cv,max = 8 pF, wherein the parasitic resistance is close to 2 Omega. The measured Insertion-Loss variation is 0.1 dB over the relative phase-shift tuning range of 237deg at 2 GHz and the return Losses are better than 20 dB, excellently agreeing with the theoretical and simulated results.
Amnon Yariv - One of the best experts on this subject based on the ideXlab platform.
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all fiber zero Insertion Loss add drop filter for wavelength division multiplexing
Optics Letters, 1998Co-Authors: Anthony S Kewitsch, George Rakuljic, Phil A Willems, Amnon YarivAbstract:We developed and fabricated an all-fiber add–drop filter by recording a Bragg grating in the waist of an asymmetric mode converter–coupler formed by adiabatic tapering and fusing of two locally dissimilar, single-mode optical fibers. The Insertion Loss of the device was ~0.1 dB. A narrow spectral bandwidth ( 90%) were also demonstrated. In addition, the filter was polarization independent.
