The Experts below are selected from a list of 360 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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microstrip elliptic function Low Pass Filters using distributed elements or slotted ground structure
IEEE Transactions on Microwave Theory and Techniques, 2006Co-Authors: Wenhua Tu, Kai ChangAbstract:This paper presents two microstrip elliptic-function Low-Pass Filters, one using distributed elements and one using a slotted ground structure. The one using distributed elements consists of a microstrip line section in parallel with an interdigital capacitor; the other one using a slotted ground structure consists of a Low-impedance microstrip line with a slotted ground structure cell under the center of the line. A transmission-line model and a full-wave simulation are used to calculate the inductance/capacitance values of the equivalent circuits. The design concept was validated through experiments showing good agreements with the full-wave simulated results
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compact elliptic function Low Pass Filters using microstrip stepped impedance hairpin resonators
IEEE Transactions on Microwave Theory and Techniques, 2003Co-Authors: Lunghwa Hsieh, Kai ChangAbstract:A compact elliptic-function Low-Pass filter using microstrip stepped-impendance hairpin resonators and their equivalent-circuit models are developed. The prototype Filters are synthesized from the equivalent-circuit model using available element-value tables. To optimize the performance of the Filters, electromagnetic simulation is used to tune the dimensions of the prototype Filters. The filter using multiple cascaded hairpin resonators provides a very sharp cutoff frequency response with Low insertion loss. Furthermore, to increase the rejection-band bandwidth, additional attenuation poles are added in the filter. The Filters are evaluated by experiment and simulation with good agreement. This simple equivalent-circuit model provides a useful method to design and understand this type of Filters and other relative circuits.
M A G Laso - One of the best experts on this subject based on the ideXlab platform.
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Accurate design of corrugated waveguide Low-Pass Filters using exclusively closed-form expressions
2017 47th European Microwave Conference (EuMC), 2017Co-Authors: F. Teberio, I Arregui, I Arnedo, T Lopetegi, J. M. Percaz, M A G LasoAbstract:A simple, quasi-analytical, and accurate method to design classical corrugated rectangular waveguide Low-Pass Filters is presented in this paper. Unlike in other published techniques, the dimensions of the final filter are directly obtained in a quasi-analytical manner folLowing exclusively closed-form expressions and, in particular, using neither electromagnetic simulation nor optimization. Thus, our method is amenable to be implemented using an off-the-shelf mathematical software tool such as Matlab. The proposed method is based on the synthesis of the heights and lengths of the final structure taking into account the shunt capacitance effect (produced by the excitation of higher-order modes at the height steps) over the magnitude and phase of the local reflection coefficients. The novel method has been validated with the design of a classical Chebyshev corrugated Low-Pass filter of order 31, which shows a remarkable accordance between the ideal and simulated frequency responses.
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chirping techniques to maximize the power handling capability of harmonic waveguide Low Pass Filters
IEEE Transactions on Microwave Theory and Techniques, 2016Co-Authors: Fernando Teberio, I Arregui, I Arnedo, M Chudzik, T Lopetegi, Adrian Gomeztorrent, M Zedler, F J Gortz, R Jost, M A G LasoAbstract:A novel chirping technique is applied to the design of very high-power waveguide harmonic Low-Pass Filters. The technique could be used, for instance, to avoid multipactor testing in multicarrier systems such as the output multiplexer of a communications satellite. The novel chirped filter shows Low insertion loss, all higher order mode suppression, and broad stopband rejection up to the third harmonic. This paper focuses on the maximization of the filter power-handling capability without affecting its excellent frequency behavior. Given a certain frequency response, the E-plane mechanical gap of the structure and the length (in the propagation direction) of the waveguide sections between its constituent bandstop elements can be considered to improve the high-power behavior. However, the power performance may not be sufficient yet in some applications if we wish, for instance, multipactor testing to be avoided. This becomes feasible by chirping the length (in the propagation direction) of the bandstop elements. An example for Ku band is discussed for relevant frequency specifications. An improvement from $\sim 8$ kW (non-chirped filter) to more than 100 kW (chirped filter) is obtained. As a reference, the equivalent waffle-iron filter can handle only 0.15 kW. Such high-power threshold levels have never been reported before for such kind of Filters.
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multipactor prediction in novel high power Low Pass Filters with wide rejection band
European Microwave Conference, 2009Co-Authors: I Arregui, S Anza, I Arnedo, C Vicente, A Lujambio, J Gil, M Chudzik, B Gimeno, T Lopetegi, M A G LasoAbstract:In this paper, the multipactor breakdown is studied in a novel design of high-power Low-Pass Filters with wide rejection band. In classical filter design techniques, there exists a trade-off between the height of the mechanical gaps and the width of the rejected band, which makes difficult the design of Filters simultaneously having wide mechanical gaps and rejected bands. These limitations are avoided by our new design based on a high-power Low-Pass filter cascaded with a quasi-periodic continuous profile folLowing Bragg reflection theory. To show this, the power handling capability of the new design fulfilling stringent frequency behaviour has been first predicted using the classical parallel-plate theory, as well as folLowing a more advanced method which considers the real electromagnetic field distribution in the component.
Lei Zhu - One of the best experts on this subject based on the ideXlab platform.
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synthesis and design of mixed lumped and distributed Low Pass Filters Low Passing impedance transformers with taylor series
IEEE Transactions on Microwave Theory and Techniques, 2016Co-Authors: Runqi Zhang, Sha Luo, Lei ZhuAbstract:In this paper, a synthesis method by applying the Taylor series is proposed to design a variety of Low-Pass mixed lumped and distributed circuit networks, including the Low-Pass Filters and Low-Passing impedance transformers. First, the principle of applying the Taylor polynomials for these mixed circuit networks is discussed. Herein, the trigonometric functions, commonly used to characterize distributed circuits, are expressed in the form of polynomials by the application of Taylor polynomials. Therefore, the transfer function of the mixed networks is simplified from a multivariable to a polynomial form. FolLowing this, a generic circuit structure is proposed to design either a Low-Pass filter or a Low-Passing impedance transformer with specified port impedances. The desired filtering function uses the similar method to transform the trigonometric function into a format of polynomials. Under the equalization of the transfer function and filtering function, all the unknown design parameters are obtained. As two examples, a Low-Pass filter and a Low-Passing impedance transformer are synthesized, designed, and fabricated to experimentally verify the proposed design approach.
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compact chebyshev function Low Pass Filters with stepped impedance hairpin unit
Asia-Pacific Microwave Conference, 2008Co-Authors: Sha Luo, Lei Zhu, Sheng SunAbstract:The objective of this paper is to study the stepped-impedance hairpin unit towards realizing three transmission zeros while applying this unit to design of multi order Low-Pass Filters with widened and deepened upper-stopband. A synthesis method is then presented to design of two Chebyshev-function Low-Pass Filters. Finally, two Low-Pass Filters of 3rd - and 5th -order are designed and fabricated. Experimental results prove that the designed Low-Pass Filters have achieved widened upper- stopband and sharpened roll-off shirt near cut-off frequencies.
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stopband expanded Low Pass Filters using microstrip coupled line hairpin units
IEEE Microwave and Wireless Components Letters, 2008Co-Authors: Sha Luo, Lei Zhu, Sheng SunAbstract:In this letter, a class of stopband-expanded Low-Pass Filters (LPFs) is proposed via attenuation poles of microstrip coupled-line hairpin unit. By centrally tap-connecting this coupled-line unit and adjusting its coupling strength, three attenuation poles can be excited above the desired Low Passband. A coupled-line-oriented closed-form model is then constructed to provide a physical insight into the excitation of these poles and to execute an efficient synthesis design of this LPF. Two prototype Filters with single and two units are finally designed with the specified cutoff frequency at 2.5 GHz. Measured results of the fabricated Filters evidently demonstrate good LPF performance, sharp roll-off skirt, and a wide upper-stopband of 3.2 to 11.8 GHz with the insertion loss higher than 20.0 dB.
Sha Luo - One of the best experts on this subject based on the ideXlab platform.
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synthesis and design of mixed lumped and distributed Low Pass Filters Low Passing impedance transformers with taylor series
IEEE Transactions on Microwave Theory and Techniques, 2016Co-Authors: Runqi Zhang, Sha Luo, Lei ZhuAbstract:In this paper, a synthesis method by applying the Taylor series is proposed to design a variety of Low-Pass mixed lumped and distributed circuit networks, including the Low-Pass Filters and Low-Passing impedance transformers. First, the principle of applying the Taylor polynomials for these mixed circuit networks is discussed. Herein, the trigonometric functions, commonly used to characterize distributed circuits, are expressed in the form of polynomials by the application of Taylor polynomials. Therefore, the transfer function of the mixed networks is simplified from a multivariable to a polynomial form. FolLowing this, a generic circuit structure is proposed to design either a Low-Pass filter or a Low-Passing impedance transformer with specified port impedances. The desired filtering function uses the similar method to transform the trigonometric function into a format of polynomials. Under the equalization of the transfer function and filtering function, all the unknown design parameters are obtained. As two examples, a Low-Pass filter and a Low-Passing impedance transformer are synthesized, designed, and fabricated to experimentally verify the proposed design approach.
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compact chebyshev function Low Pass Filters with stepped impedance hairpin unit
Asia-Pacific Microwave Conference, 2008Co-Authors: Sha Luo, Lei Zhu, Sheng SunAbstract:The objective of this paper is to study the stepped-impedance hairpin unit towards realizing three transmission zeros while applying this unit to design of multi order Low-Pass Filters with widened and deepened upper-stopband. A synthesis method is then presented to design of two Chebyshev-function Low-Pass Filters. Finally, two Low-Pass Filters of 3rd - and 5th -order are designed and fabricated. Experimental results prove that the designed Low-Pass Filters have achieved widened upper- stopband and sharpened roll-off shirt near cut-off frequencies.
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stopband expanded Low Pass Filters using microstrip coupled line hairpin units
IEEE Microwave and Wireless Components Letters, 2008Co-Authors: Sha Luo, Lei Zhu, Sheng SunAbstract:In this letter, a class of stopband-expanded Low-Pass Filters (LPFs) is proposed via attenuation poles of microstrip coupled-line hairpin unit. By centrally tap-connecting this coupled-line unit and adjusting its coupling strength, three attenuation poles can be excited above the desired Low Passband. A coupled-line-oriented closed-form model is then constructed to provide a physical insight into the excitation of these poles and to execute an efficient synthesis design of this LPF. Two prototype Filters with single and two units are finally designed with the specified cutoff frequency at 2.5 GHz. Measured results of the fabricated Filters evidently demonstrate good LPF performance, sharp roll-off skirt, and a wide upper-stopband of 3.2 to 11.8 GHz with the insertion loss higher than 20.0 dB.
Tsuyoshi Hanamoto - One of the best experts on this subject based on the ideXlab platform.
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wide speed range sensorless vector control of synchronous reluctance motors based on extended programmable cascaded Low Pass Filters
IEEE Transactions on Industrial Electronics, 2011Co-Authors: Ahmad Ghaderi, Tsuyoshi HanamotoAbstract:This paper proposes a new sensorless vector control of a synchronous reluctance motor for a wide range of speeds. The estimation of speed and rotor angle is based on extended programmable cascaded Low-Pass Filters (LPFs), which effectively reduce the effects of direct-current (dc) offsets at Low speeds. The effect of the number of LPF stages on output dc offset, estimation accuracy, and dynamic performance are determined, and their equations are developed. The determination of the number of LPF stages is based on these developed equations. Because the estimate of the rotor angle near-zero speed is possible, the motor start-up procedure can be done without complexity. The experimental results show that the estimated and the actual rotor angles are in agreement at very Low and high speeds. Thus, sensorless vector control can be achieved over a wide range of speeds. In addition, motor start-up in a standstill condition is possible, and the transient response at Low and high speeds is acceptable.
