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Search Results: 1 - 10 of 214419 matches for " Lei Chang;Haijing Zhou;Ling-Lu Chen;Xiang-Zheng Xiong;Cheng Liao "
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The Fine-Grained Parallel Micro-Genetic Algorithm and its Application to Broadband Conical Corrugated-Horn Antenna
Lei Chang;Haijing Zhou;Ling-Lu Chen;Xiang-Zheng Xiong;Cheng Liao
PIER , 2013, DOI: 10.2528/PIER13030908
Abstract: The fine-grained parallel micro-genetic algorithm (FGPMGA) is developed to solve antenna design problems. The synthesis of uniformly exited unequally spaced array is presented. Comparison with the micro-genetic algorithm (MGA) has been carried out. It is seen that the FGPMGA significantly outperforms MGA, in terms of both the convergence rate and exploration ability. The FGPMGA can also reduce the optimization time. Then the FGPMGA and the body of revolution finite-difference time-domain (BOR-FDTD) are combined to achieve an automated design process for conical corrugated-horn antenna. Numerical simulation results show that the horn antenna has good impedance matching (the VSWR is less than 1.5), stable beamwidth and gain, as well as good rotation symmetry patterns over the whole band 8~13 GHz.
A Hybrid Method Based on Differential Evolution and Continuous Ant Colony Optimization and its Application on Wideband Antenna Design
Lei Chang;Cheng Liao;Wenbin Lin;Ling-Lu Chen;Xuan Zheng
PIER , 2012, DOI: 10.2528/PIER11092207
Abstract: An evolutionary learning algorithm based on differential evolution strategy (DES) and continuous ant colony optimization (CACO) for wideband antenna design is proposed. The advantages of this hybrid method are demonstrated with several mathematical functions and a linear array pattern synthesis. This method is applied to design an E-shaped wideband patch antenna, which achieves the impedance bandwidth 4.8 ~ 6.53 GHz. We compare the hybrid method with the traditional DES and CACO optimization algorithms, and the advantage of this hybrid method over the DES and the CACO is also demonstrated.
Design of an Ultra-Wideband Power Divider via the Coarse-Grained Parallel Micro-Genetic Algorithm
Lei Chang;Cheng Liao;Ling-Lu Chen;Wenbin Lin;Xuan Zheng;Yan-Liang Wu
PIER , 2012, DOI: 10.2528/PIER11120517
Abstract: An ultra-wideband (UWB) power divider is designed in this paper. The UWB performance of this power divider is obtained by using a tapered microstrip line that consists of exponential and elliptic sections. The coarse grained parallel micro-genetic algorithm (PMGA) and CST Microwave Studio are combined to achieve an automated parallel design process. The method is applied to optimize the UWB power divider. The optimized power divider is fabricated and measured. The measured results show relatively low insertion loss, good return loss, and high isolation between the output ports across the whole UWB (3.1-10.6 GHz).
A Time-Domain Approach for the Fast Design of Reflector Impulse-Radiating Antennas
Ling-Lu Chen;Ju Feng;Lei Chang;Cheng Liao
PIER , 2013, DOI: 10.2528/PIER12111405
Abstract: It is difficult to determine the feed radiation center and F/D of the reflector impulse-radiating antenna (IRA) in frequencydomain, due to its ultra-wideband (UWB) property. This paper presents an efficient approach to design the reflector IRAs, via evaluating the transient radiation patterns (TRPs) of the feed for some given different radiation centers. Only one time-domain simulation for the feed is needed in this method. Comparing with the global optimization algorithms, our method is fast and reliable in the design of the reflector IRAs.
Hybrid-Surrogate-Model-Based Efficient Global Optimization for High-Dimensional Antenna Design
Ling-Lu Chen;Cheng Liao;Wenbin Lin;Lei Chang;Xuan-Ming Zhong
PIER , 2012, DOI: 10.2528/PIER11121203
Abstract: Efficient global optimization has been extensively used in problems with expensive cost functions. However, this method is not suitable for high-dimensional problems. In this paper, the radial basis function network is introduced into the efficient global optimization, to avoid local optima and achieve a fast convergence for high-dimensional optimization. Our algorithm is applied to a 12-dimensional optimization of a transmitting antenna. Compared to the genetic-algorithm-based efficient global optimization and the differential evolution strategy, our algorithm converges to the global optimal value more efficiently.
A Dual-Wideband Bandpass Filter Based on E-Shaped Microstrip Sir with Improved Upper-Stopband Performance
Yan-Liang Wu;Cheng Liao;Xiang-Zheng Xiong
PIER , 2010, DOI: 10.2528/PIER10071802
Abstract: A novel dual-wideband microstrip bandpass filter (BPF) with improved upper-stopband performance is presented. With the use of some special structures such as E-shaped microstrip Stepped-Impedance Resonator (SIR) and input-output cross-coupling feed structure, this filter can generate five transmission zeros which are beneficial for improving its frequency selectivity and upper-stopband performance. Finally the microstrip dual-wideband BPF has been simulated, fabricated and measured. Measurement results show that the two passbands are centered at 3.7 GHz and 5.8 GHz with the fractional bandwidth of 31% and 13% respectively. Meanwhile more than 50% relative upper stopband bandwidth with 20 dB rejection has been realized. The simulated and measured results are in good agreement.
A complete mitochondrial genome sequence of Asian black bear Sichuan subspecies (Ursus thibetanus mupinensis)
Wan-ru Hou, Yu Chen, Xia Wu, Jin-chu Hu, Zheng-song Peng, Jung Yang, Zong-xiang Tang, Cai-Quan Zhou, Yu-ming Li, Shi-kui Yang, Yu-jie Du, Ling-lu Kong, Zheng-long Ren, Huai-yu Zhang, Su-rong Shuai
International Journal of Biological Sciences , 2007,
Abstract: We obtained the complete mitochondrial genome of U.thibetanus mupinensis by DNA sequencing based on the PCR fragments of 18 primers we designed. The results indicate that the mtDNA is 16 868 bp in size, encodes 13 protein genes, 22 tRNA genes, and 2 rRNA genes, with an overall H-strand base composition of 31.2% A, 25.4% C, 15.5% G and 27.9% T. The sequence of the control region (CR) located between tRNA-Pro and tRNA-Phe is 1422 bp in size, consists of 8.43% of the whole genome, GC content is 51.9% and has a 6bp tandem repeat and two 10bp tandem repeats identified by using the Tandem Repeats Finder. U. thibetanus mupinensis mitochondrial genome shares high similarity with those of three other Ursidae: U. americanus (91.46%), U. arctos (89.25%) and U. maritimus (87.66%).
Design Filters Using Tunable E-Shaped Dual-Mode Resonators for Lower-Ultra-Wideband and Upper-Ultra-Wideband Applications
Yan-Liang Wu;Cheng Liao;Xiang-Zheng Xiong;Xuan-Ming Zhong
PIER C , 2013, DOI: 10.2528/PIERC12111808
Abstract: Two ultra-wideband (UWB) microstrip bandpass filters (BPFs) are proposed by using tunable E-shaped dual-mode microstrip Stepped-Impedance Resonator (SIR). For the lower band filter measurement results show there is a passband of 3.1 GHz to 5.2 GHz and its 3 dB fractional bandwidth is 51%. The UWB upper band filter may be obtained by tuning E-shaped SIR. The measurement results show there is a passband of 6 GHz to 10.6 GHz and its 3 dB fractional bandwidth is 55%. Compared with the similar investigation using the cascade of electromagnetic band gap (EBG)-embedded multiplemode resonator (MMR) and fork resonator, the proposed approach has some advantages, such as easier adjustment of bandwidths, better passband performances and smaller size etc.
Microwave transmissions through superconducting coplanar waveguide resonators with different coupling configurations
Zhang Si-Lei,Li Hai-Jie,L. F. Wei,Fang Yu-Rong,Wang Yi-Wen,Zhou Pin-Jia,Wei Qiang,Cao Chun-Hai,Xiong Xiang-Zheng
Physics , 2013,
Abstract: We design and fabricate two types of superconducting niobium coplanar waveguide microwave resonators with different coupling capacitors on high purity Si substrates. Their microwave transmissions are measured at the temperatures of 20 mK. It is found that these two types of resonators possess significantly-different loaded quality factors; one is $5.6\times{10}^{3}$, and the other is $4.0\times{10}^{4}$. The measured data are fitted well by classical ABCD matrix approach. We found that the transmission peak deviates from the standard Lorentizian with a frequency broadening.
A Hybrid Optimized Algorithm Based on Ego and Taguchi's Method for Solving Expensive Evaluation Problems of Antenna Design
Nan Sheng;Cheng Liao;Wenbin Lin;Lei Chang;Qinghong Zhang;Haijing Zhou
PIER C , 2010, DOI: 10.2528/PIERC10091303
Abstract: In this paper, we propose a hybrid optimization approach that combines the Efficient Global Optimization (EGO) algorithm with Taguchi's method. This hybrid optimized algorithm is suited for problems with expensive cost functions. As a Bayesian analysis optimization algorithm, EGO algorithm begins with fitting the Kriging model with n sample points, and finds the (n+1)th point where the expected improvement is maximized to update the model. We employ Taguchi's method in EGO to obtain the (n+1)th point in this paper. A numerical simulation demonstrates that our algorithm has advantage over the original EGO. Finally, we apply this hybrid optimized algorithm to optimize an ultra-wide band (UWB) transverse electromagnetic (TEM) horn antenna and a linear antenna array. Compared to Taguchi's method and the Integer Coded Differential Evolution Strategy, our algorithm converges to the global optimal value more efficiently.
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