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基于半圆异向波导的新型带通滤波器 被引量:1
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作者 张信歌 李少甫 《电子元件与材料》 CAS CSCD 2015年第2期58-61,共4页
根据异向传输线原理设计了一种半圆异向波导单元,基于该单元提出了一种新型带通滤波器。利用HFSS软件对级联的四阶单元进行仿真,研究了其不同结构参数对电磁波传输的影响。用八阶单元构成中心频率为2.8 GHz的新型带通滤波器,利用HFS... 根据异向传输线原理设计了一种半圆异向波导单元,基于该单元提出了一种新型带通滤波器。利用HFSS软件对级联的四阶单元进行仿真,研究了其不同结构参数对电磁波传输的影响。用八阶单元构成中心频率为2.8 GHz的新型带通滤波器,利用HFSS软件在S波段对其进行模拟。结果为:异向通带为2.25~3.25 GHz,3 dB带宽达35.7%。利用理论分析与仿真相结合的方法,验证了该滤波器具有异向特性,与常规波导滤波器及基于微带线异向传输线实现的滤波器相比该滤波器具有小尺寸、低成本、高功率容量、低损耗、带外衰减特性好等优点。 展开更多
关键词 带通滤波器 S波段 异向传输线 半圆波导 异向波导 异向通带
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An adaptive noise attenuation method for edge and amplitude preservation 被引量:3
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作者 蔡涵鹏 贺振华 +4 位作者 李亚林 何光明 邹文 张洞君 刘璞 《Applied Geophysics》 SCIE CSCD 2014年第3期289-300,351,共13页
Noise intensity distributed in seismic data varies with different frequencies or frequency bands; thus, noise attenuation on the full-frequency band affects the dynamic properties of the seismic reflection signal and ... Noise intensity distributed in seismic data varies with different frequencies or frequency bands; thus, noise attenuation on the full-frequency band affects the dynamic properties of the seismic reflection signal and the subsequent seismic data interpretation, reservoir description, hydrocarbon detection, etc. Hence, we propose an adaptive noise attenuation method for edge and amplitude preservation, wherein the wavelet packet transform is used to decompose the full-band seismic signal into multiband data and then process these data using nonlinear anisotropic dip-oriented edge-preserving fi ltering. In the fi ltering, the calculated diffusion tensor from the structure tensor can be exploited to establish the direction of smoothing. In addition, the fault confidence measure and discontinuity operator can be used to preserve the structural and stratigraphic discontinuities and edges, and the decorrelation criteria can be used to establish the number of iterations. These parameters can minimize the intervention and subjectivity of the interpreter, and simplify the application of the proposed method. We applied the proposed method to synthetic and real 3D marine seismic data. We found that the proposed method could be used to attenuate noise in seismic data while preserving the effective discontinuity information and amplitude characteristics in seismic refl ection waves, providing high-quality data for interpretation and analysis such as high-resolution processing, attribute analysis, and inversion. 展开更多
关键词 Multiscale nonlinear anisotropic dip-oriented filtering noise attenuation stopping criterion ITERATION confi dence measure
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High-Order Radial Derivatives of Harmonic Function and Gravity Anomaly 被引量:8
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作者 Ziqing Wei 《Journal of Physical Science and Application》 2014年第7期454-467,共14页
The first through ninth radial derivatives of a harmonic function and gravity anomaly are derived in this paper. These derivatives can be used in the analytical continuation application. For the downward continuation ... The first through ninth radial derivatives of a harmonic function and gravity anomaly are derived in this paper. These derivatives can be used in the analytical continuation application. For the downward continuation of gravity anomaly, the Taylor series approach developed in the paper is equivalent theoretically to but more efficient and storage-saving computationally than the well-known gradient operator approach. Numerical simulation shows that Taylor series expansion constructed by the derived formulas for the radial derivatives of gravity disturbance is still convergent for height up to 4 km. 展开更多
关键词 Harmonic function gravity anomaly gravity disturbance high-order radial derivative analytical continuation.
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