A hybrid method for synthesizing antenna＇s three dimensional （3D） pattern is proposed to obtain the low sidelobe feature of truncated cone conformal phased arrays. In this method, the elements of truncated cone con...A hybrid method for synthesizing antenna＇s three dimensional （3D） pattern is proposed to obtain the low sidelobe feature of truncated cone conformal phased arrays. In this method, the elements of truncated cone conformal phased arrays are projected to the tangent plane in one generatrix of the truncated cone. Then two dimensional （2D） Chebyshev amplitude distribution optimization is respectively used in two mutual vertical directions of the tangent plane. According to the location of the elements, the excitation current amplitude distribution of each element on the conformal structure is derived reversely, then the excitation current amplitude is further optimized by using the genetic algorithm （GA）. A truncated cone problem with 8x8 elements on it, and a 3D pattern desired side lobe level （SLL） up to 35 dB, is studied. By using the hybrid method, the optimal goal is accomplished with acceptable CPU time, which indicates that this hybrid method for the low sidelobe synthesis is feasible.展开更多
Recently, we found that side lobes of wavelets have a large impact on the identification of thin sand reservoirs when studying some gas fields in a basin in Northwest China. Reflections from the top of the H Formation...Recently, we found that side lobes of wavelets have a large impact on the identification of thin sand reservoirs when studying some gas fields in a basin in Northwest China. Reflections from the top of the H Formation, in which there are gas-bearing thin sand bodies, have the main wavelet lobe between two weak peak side lobes. The lower one always mixes with another peak reflected from the top of a thin sand reservoir. That makes it difficult to identify the sand reservoir. In order to solve this, many forward models were set up using typical well logs. 2D synthetic profiles were produced using Ricker wavelets to study the relationships between the effects of wavelet side lobes and thin sand position and frequency and between amplitude and the thin sand body. We developed the following conclusions： First, it is easier to identify thin sands in a shallower position. Second, a good way to tell sand body reflections from side lobes is by comparing profiles with different frequency windows. Third, it is helpful and effective to describe sand extent using amplitude attributes.展开更多
Thinning of antenna arrays has been a popular topic for the last several decades.With increasing computational power,this optimization task acquired a new hue.This paper suggests a genetic algorithm as an instrument f...Thinning of antenna arrays has been a popular topic for the last several decades.With increasing computational power,this optimization task acquired a new hue.This paper suggests a genetic algorithm as an instrument for antenna array thinning.The algorithm with a deliberately chosen fitness function allows synthesizing thinned linear antenna arrays with low peak sidelobe level(SLL)while maintaining the half-power beamwidth(HPBW)of a full linear antenna array.Based on results from existing papers in the field and known approaches to antenna array thinning,a classification of thinning types is introduced.The optimal thinning type for a linear thinned antenna array is determined on the basis of a maximum attainable SLL.The effect of thinning coefficient on main directional pattern characteristics,such as peak SLL and HPBW,is discussed for a number of amplitude distributions.展开更多
Purpose-The purpose of this paper is to improve energy efficiency and further reduction of side lobe level the algorithm proposed is firework algorithm.In this paper,roused by the eminent swarm conduct of firecrackers...Purpose-The purpose of this paper is to improve energy efficiency and further reduction of side lobe level the algorithm proposed is firework algorithm.In this paper,roused by the eminent swarm conduct of firecrackers,a novel multitude insight calculation called fireworks algorithm(FA)is proposed for work enhancement.The FA is introduced and actualized by mimicking the blast procedure of firecrackers.In the FA,two blast(search)forms are utilized and systems for keeping decent variety of sparkles are likewise all around planned.To approve the presentation of the proposed FA,correlation tests were led on nine benchmark test capacities among the FA,the standard PSO(SPSO)and the clonal PSO(CPSO).Design/methodology/approach-The antenna arrays are used to improve the capacity and spectral efficiency of wireless communication system.The latest communication systems use the antenna array technology to improve the spectral efficiency,fill rate and the energy efficiency of the communication system can be enhanced.One of the most important properties of antenna array is beam pattern.A directional main lobe with low side lobe level(SLL)of the beam pattern will reduce the interference and enhance the quality of communication.The classical methods for reducing the side lobe level are differential evolution algorithm and PSO algorithm.In this paper,roused by the eminent swarm conduct of firecrackers,a novel multitude insight calculation called fireworks algorithm(FA)is proposed for work enhancement.The FA is introduced and actualized by mimicking the blast procedure of firecrackers.In the FA,two blast(search)forms are utilized and systems for keeping decent variety of sparkles are likewise all around planned.To approve the presentation of the proposed FA,correlation tests were led on nine benchmark test capacities among the FA,the standard PSO(SPSO)and the clonal PSO(CPSO).It is demonstrated that the FA plainly beats the SPSO and the CPSO in both enhancement exactness and combination speed.The results convey that the side lobe level is reduced to34.78dB and fill rate is increased to 78.53.Findings-Samples including 16-element LAAs are conducted to verify the optimization performances of the SLL reductions.Simulation results show that the SLLs can be effectively reduced by FA.Moreover,compared with other benchmark algorithms,fireworks has a better performance in terms of the accuracy,the convergence rate and the stability.Research limitations/implications-With the use of algorithms radiation is prone to noise one way or other.Even with any optimizations we cannot expect radiation to be ideal.Power dissipation or electro magnetic interference is bound to happen,but the use of optimization algorithms tries to reduce them to the extent that is possible.Practical implications-16-element linear antenna array is available with latest versions of Matlab.Social implications-The latest technologies and emerging developments in the field of communication and with exponential growth in users the capacity of communication system has bottlenecks.The antenna arrays are used to improve the capacity and spectral efficiency of wireless communication system.The latest communication systems use the antenna array technology which is to improve the spectral efficiency,fill rate and the energy efficiency of the communication system can be enhanced.Originality/value-By using FA,the fill rate is increased to 78.53 and the side lobe level is reduced to 35dB,when compared with the bench mark algorithms.展开更多
基金supported by the Fundamental Research Funds for the Central Universities(YWF-13D2-XX-13)the National High-tech Research and Development Program(863 Program)(2008AA121802)
文摘A hybrid method for synthesizing antenna＇s three dimensional （3D） pattern is proposed to obtain the low sidelobe feature of truncated cone conformal phased arrays. In this method, the elements of truncated cone conformal phased arrays are projected to the tangent plane in one generatrix of the truncated cone. Then two dimensional （2D） Chebyshev amplitude distribution optimization is respectively used in two mutual vertical directions of the tangent plane. According to the location of the elements, the excitation current amplitude distribution of each element on the conformal structure is derived reversely, then the excitation current amplitude is further optimized by using the genetic algorithm （GA）. A truncated cone problem with 8x8 elements on it, and a 3D pattern desired side lobe level （SLL） up to 35 dB, is studied. By using the hybrid method, the optimal goal is accomplished with acceptable CPU time, which indicates that this hybrid method for the low sidelobe synthesis is feasible.
文摘Recently, we found that side lobes of wavelets have a large impact on the identification of thin sand reservoirs when studying some gas fields in a basin in Northwest China. Reflections from the top of the H Formation, in which there are gas-bearing thin sand bodies, have the main wavelet lobe between two weak peak side lobes. The lower one always mixes with another peak reflected from the top of a thin sand reservoir. That makes it difficult to identify the sand reservoir. In order to solve this, many forward models were set up using typical well logs. 2D synthetic profiles were produced using Ricker wavelets to study the relationships between the effects of wavelet side lobes and thin sand position and frequency and between amplitude and the thin sand body. We developed the following conclusions： First, it is easier to identify thin sands in a shallower position. Second, a good way to tell sand body reflections from side lobes is by comparing profiles with different frequency windows. Third, it is helpful and effective to describe sand extent using amplitude attributes.
文摘Thinning of antenna arrays has been a popular topic for the last several decades.With increasing computational power,this optimization task acquired a new hue.This paper suggests a genetic algorithm as an instrument for antenna array thinning.The algorithm with a deliberately chosen fitness function allows synthesizing thinned linear antenna arrays with low peak sidelobe level(SLL)while maintaining the half-power beamwidth(HPBW)of a full linear antenna array.Based on results from existing papers in the field and known approaches to antenna array thinning,a classification of thinning types is introduced.The optimal thinning type for a linear thinned antenna array is determined on the basis of a maximum attainable SLL.The effect of thinning coefficient on main directional pattern characteristics,such as peak SLL and HPBW,is discussed for a number of amplitude distributions.
文摘Purpose-The purpose of this paper is to improve energy efficiency and further reduction of side lobe level the algorithm proposed is firework algorithm.In this paper,roused by the eminent swarm conduct of firecrackers,a novel multitude insight calculation called fireworks algorithm(FA)is proposed for work enhancement.The FA is introduced and actualized by mimicking the blast procedure of firecrackers.In the FA,two blast(search)forms are utilized and systems for keeping decent variety of sparkles are likewise all around planned.To approve the presentation of the proposed FA,correlation tests were led on nine benchmark test capacities among the FA,the standard PSO(SPSO)and the clonal PSO(CPSO).Design/methodology/approach-The antenna arrays are used to improve the capacity and spectral efficiency of wireless communication system.The latest communication systems use the antenna array technology to improve the spectral efficiency,fill rate and the energy efficiency of the communication system can be enhanced.One of the most important properties of antenna array is beam pattern.A directional main lobe with low side lobe level(SLL)of the beam pattern will reduce the interference and enhance the quality of communication.The classical methods for reducing the side lobe level are differential evolution algorithm and PSO algorithm.In this paper,roused by the eminent swarm conduct of firecrackers,a novel multitude insight calculation called fireworks algorithm(FA)is proposed for work enhancement.The FA is introduced and actualized by mimicking the blast procedure of firecrackers.In the FA,two blast(search)forms are utilized and systems for keeping decent variety of sparkles are likewise all around planned.To approve the presentation of the proposed FA,correlation tests were led on nine benchmark test capacities among the FA,the standard PSO(SPSO)and the clonal PSO(CPSO).It is demonstrated that the FA plainly beats the SPSO and the CPSO in both enhancement exactness and combination speed.The results convey that the side lobe level is reduced to34.78dB and fill rate is increased to 78.53.Findings-Samples including 16-element LAAs are conducted to verify the optimization performances of the SLL reductions.Simulation results show that the SLLs can be effectively reduced by FA.Moreover,compared with other benchmark algorithms,fireworks has a better performance in terms of the accuracy,the convergence rate and the stability.Research limitations/implications-With the use of algorithms radiation is prone to noise one way or other.Even with any optimizations we cannot expect radiation to be ideal.Power dissipation or electro magnetic interference is bound to happen,but the use of optimization algorithms tries to reduce them to the extent that is possible.Practical implications-16-element linear antenna array is available with latest versions of Matlab.Social implications-The latest technologies and emerging developments in the field of communication and with exponential growth in users the capacity of communication system has bottlenecks.The antenna arrays are used to improve the capacity and spectral efficiency of wireless communication system.The latest communication systems use the antenna array technology which is to improve the spectral efficiency,fill rate and the energy efficiency of the communication system can be enhanced.Originality/value-By using FA,the fill rate is increased to 78.53 and the side lobe level is reduced to 35dB,when compared with the bench mark algorithms.
