Hong-Min Lee, Joong-kwan Kim, Sung-Soo Nam · 2009
In this paper, to suppress the surface wave in dielectric substrate novel soft surface structure is proposed. In case of microstrip patch antenna design with finite ground plane, most of the backward radiation is induced due to surface waves which flow through the ground plane. By using the proposed soft surface structure, backward radiation power of a microstrip patch antenna is reduced −7 dBi compare to a conventional microstrip patch antenna without a soft surface.
Cited by 2
Muhammad Syamim Fitri Othman, Kamilia Kamardin, Yoshihide Yamada et al. · 2024
In the case of radio wave propagation measurement using a seawater tank, large surface wave produced at the tank wall will limit the measurement area. In order to reduce the surface wave, to attach some structure on the tank wall may be expected. In this paper, small pyramidal structure, metal plate and wire mesh attachment are investigated through electromagnetic simulations. It is concluded that both metal plate and wire mesh structures can effectively reduce the surface wave more than 20dB.
Cited by 2
Deying Wang, Zhenchun Li, Jianping Huang et al. · 2014
Surface wave attenuation is one of the most important step during land seismic data processing, most of the current methods to attenuate the surface wave are based on the difference between the signal and noise in energy aspect, which means only the amplitude spectrum is concerned but without the phase, therefore with the current methods if the frequency band will be preserved, to some extend the surface wave character will also be preserved which results in the incomplete attenuation of the surface wave. This article provides one new method that using the polynomial fitting of the changing relationship between the signal spectrum ratio and the offset to restore the signal amplitude spectrum in the surface wave area, and in the same time the data is converted to angle frequency-wavenumber domain, in which the signal and surface wave was separated according to their characteristics in the concerning of the phase spectrum. In this article the parameters of the seismic waves are obtained by the fitting of reflection signal, maybe it has some self-adaptation. Both the model-based and practical data were used to test this new method, the result shows that it is necessary to concern the phase spectrum in the data processing, accompanied with the amplitude spectrum processing the surface wave can be removed thoroughly. The spectrum analysis show that the surface wave can be removed thoroughly and meanwhile with a good amplitude-preservation. In another way, when compared with the FK method this new method performs much better in the preservation of the low-frequency.
Cited by 0
Symon K. Podilchak, Paolo Baccarelli, Paolo Burghignoli et al. · 2014
Planar periodic `bull-eye' leaky-wave antennas are investigated for two-sided frequency beam scanning and broadside radiation at microwave and millimeter-wave frequencies. In particular, the ground plane and the radial configuration of the structures are optimized to support leakage of the fundamental TM mode of the guiding structure in a regime without any other modes, either bound or radiating, while also taking into consideration the TM and TE fields generated by the practical slot source integrated into the bottom ground plane. These design approaches can improve beam scanning quality, reduce reflection losses, minimize cross-polarization levels, and increase antenna gain. In addition, full-wave simulations and antenna measurements are in agreement with the developed Method of Moments dispersion analysis where continuous wide-angle beam scanning is observed over a large radiating bandwidth.
Cited by 1
Nelin, E. A., Nepochatykh, Yu. V. · Bulletin Of The NTUU "KPI". Series Radiotechnics, Radio Apparatus Building (National Technical University of Ukraine) · 2016
Introduction. One of the dominant second order effects in devices based on surface acoustic waves (SAW) is the excitation of parasitic bulk acoustic waves (BAW). Attention is drawn to the lack of effectiveness of traditional BAW suppression ways. Traditional ways of suppressing the bulk acoustic waves. Provides an overview of how suppression of parasitic BAW to SAW filters. One way allows to reach a record level of BAW suppression (−65 dB) due to the significant mechanical weakening of the acoustic line of the filter. Narrowband surface acoustic wave filter. It is found that in the SAW filter with an extremely high level of out-of-band suppression (−72 dB) traditional ways do not provide the required level of suppression of BAW. Wave heterogeneity of special shape. Tested the effectiveness of the authors proposed way of BAW suppression in a narrow-band SAW filter with an extremely high level of out-of-band suppression. A deep closed groove which is cut in the lower surface of the acoustic line of filter reduces the level of BAW to −70 dB, and the strength of the acoustic line of filter is almost not reduced. The dependence of suppression the bulk acoustic waves from the parameters of the wave heterogeneity. The dependence of the relative level (B) of suppression the slow quasi-shear bulk acoustic waves from the depth of the closed groove was investigated. It was found a monotonic increase in the level of B with increasing groove depth. Level B = −70 dB was obtained when the thickness of the gap between the bottom of the groove and the working surface of the acoustic line was (for different filter samples). Conclusion. The effectiveness of the authors proposed way of suppression the slow quasi-shear BAW in SAW filters is proved. A deep closed groove which is cut into the bottom surface of the acoustic line of filter can suppress slow quasi-shear BAW to a level of −70 dB.
Cited by 0Open access
W.J. Tanski, J. Acevedo, Richard A. Moore · 1973
Cited by 5
Otajonova Sh. Kh., Mamarozikov T.U. · Zenodo (CERN European Organization for Nuclear Research) · 2023
In this paper, we consider the use of the seismic receiver grouping method in order to suppress the surface wave at the stage of recording elastic vibrations. As a result of the work, the optimal parameters of a group of receivers were calculated, a plan for the spectral directivity characteristic was built, and a comparative analysis of real and simulated seismograms was carried out using window estimates.
Cited by 0Open access
Bae‐Ian Wu, Hongsheng Chen, Jin Au Kong et al. · Journal of Applied Physics · 2007
In the presence of normal substrates, it is well known that there exists strong transverse magnetic (TM) surface wave coupling between antenna ports on a shared ground plane. Through the analysis of surface wave propagation, such coupling is proposed to be substantially decreased via the use of magnetic metamaterials. The design and the characterization of the metamaterials are presented, and it is shown that within a certain frequency band, the material behaves as an anisotropic magnetic plasma, suppressing the propagation of a TM surface wave. Experimental measurements further confirm such a suppression, and an isolation improvement of 15 dB between an aperture spaced 9.2 cm apart is observed, in agreement with numerical simulations.
Cited by 24
Faezeh Shirmohammadi, Deyan Draganov, Ranajit Ghose et al. · arXiv (Cornell University) · 2024
High-resolution seismic reflections are essential for imaging and monitoring applications. In seismic land surveys using sources and receivers at the surface, surface waves often dominate, masking the reflections. In this study, we demonstrate the efficacy of a two-step procedure to suppress surface waves in an active-source reflection seismic dataset. First, we apply seismic interferometry (SI) by cross-correlation, turning receivers into virtual sources to estimate the dominant surface waves. Then, we perform adaptive subtraction to minimise the difference between the surface waves in the original data and the result of SI. We propose a new approach where the initial suppression results are used for further iterations, followed by adaptive subtraction. This technique aims to enhance the efficacy of data-driven surface-wave suppression through an iterative process. We use a 2D seismic reflection dataset from Scheemda, situated in the Groningen province of the Netherlands, to illustrate the technique's efficiency. A comparison between the data after recursive interferometric surface-wave suppression and the original data across time and frequency-wavenumber domains shows significant suppression of the surface waves, enhancing visualization of the reflections for following subsurface imaging and monitoring studies.
Cited by 0Open access
Cheng Xiangxian · 2014
Based on electromagnetic wave theory,the paper demonstrates that magnetic metamaterial can be used to suppress the surface wave existing between the shipboard coplanar array antennas.A model containing two antenna ports on a perfect electric conductor(PEC)plane with a magnetic metamaterial slab in the middle is created in CST MWS and time-domain solver is applied by making use of finite integration time domain,(FITD)method.Simulation results indicates that magnetic metamaterial increases the isolation between coplanar antennas in the frequency band where the real part of metamaterial effective permeability is negative,and the backscattering values are depressed simultaneously.The thickness of magnetic metamaterial slab is found to be an important factor as well as its effective constitutive parameters,because both electromagnetic compatibility(EMC)and stealth performance are influenced significantly by the thickness of metamaterial slab,but working in different directions.
Cited by 2
Ahmet C. Durgun, Constantine A. Balanis, Craig R. Birtcher · 2013
Surface wave suppression properties of Perforated Artificial Impedance Surfaces (PAIS) are investigated. It is shown that, by a proper choice of perforation geometry, surface wave propagation can be suppressed without the need of vias. This significantly decreases fabrication costs. It is also possible to overlap the surface wave suppression and reflection phase bands of the PAIS. Due to the rotational asymmetry of the structure, surface wave suppression is achieved in only one direction.
Cited by 2
Dinuo Bu, Shi‐Wei Qu · 2024
In this paper, a method is proposed to suppress the surface waves guided by the wide-angle impedance matching (WAIM) layer in millimeter-wave planar ultrawideband modular antennas. Based on the analysis of the magnetic-fields and Poynting-vector distributions, a novel metallic structure is proposed, which suppresses the surface-wave mode effectively. By adding the metallic structures at the critical positions within the WAIM layer, the surface waves are suppressed while maintaining good radiation. Consequently, the proposed antenna array can scan to ±60° in E/H planes with active VSWRs < 3 in 21–69GHz.
Cited by 0
Faezeh Shirmohammadi, Deyan Draganov, Ranajit Ghose et al. · Geophysical Journal International · 2025
SUMMARY High-resolution seismic reflections are essential for imaging and monitoring applications. In seismic land surveys using sources and receivers at the surface, surface waves often dominate, masking the reflections. In this study, we demonstrate the efficacy of a two-step procedure to suppress surface waves in an active-source reflection seismic data set. First, we apply seismic interferometry (SI) by cross-correlation, turning receivers into virtual sources to estimate the dominant surface waves. Then, we perform adaptive subtraction to minimize the difference between the surface waves in the original data and the result of SI. We propose a new approach where the initial suppression results are used for further iterations, followed by adaptive subtraction. This technique aims to enhance the efficacy of data-driven surface-wave suppression through an iterative process. We use a 2-D seismic reflection data set from Scheemda, situated in the Groningen province of the Netherlands, to illustrate the technique’s efficiency. A comparison between the data after recursive interferometric surface-wave suppression and the original data across time and frequency–wavenumber domains shows significant suppression of the surface waves, enhancing visualization of the reflections for subsequent subsurface imaging and monitoring studies.
Cited by 0Open access
Lei Gao, Shijun Zheng, Fan Min · Geophysical Prospecting · 2026
ABSTRACT Noise in seismic data includes random noise and coherent noise. Surface waves, as typical coherent noise, are characterized by low‐frequency, low apparent velocity and high amplitude. Its physical propagation characteristics are similar to some effective signals, which leads to the difficulty of distinguishing them in the time‐frequency domain. Convolutional neural networks have been increasingly used for surface wave suppression due to their adaptive feature extraction. However, they struggle in separating surface waves from effective signals with their overlapping frequency range. In this paper, we propose a wave‐attention hybrid network (WAHNet) to handle this issue. WAHNet has two types of new modules: (1) wavelet‐gated enhancement module extracts and enhances the time‐frequency domain features of seismic signals by combining wavelet convolution with a gating mechanism and (2) adaptive wavelet attention module introduces a joint attention mechanism in the time‐frequency domain to alleviate the time‐frequency aliasing problem of surface waves and effective signals. The experimental results show that, compared with the five popular methods, WAHNet can suppress surface waves more effectively while retaining richer effective signals.
Cited by 0
Jingjing Zheng, Xingyao Yin, Guangzhi Zhang et al. · Applied Geophysics · 2010
Cited by 21
Phillip Durdaut, Anne Kittmann, Andreas Bahr et al. · IEEE Sensors Journal · 2018
Surface acoustic wave (SAW) sensors are widely used in different fields of application. In order to maximize the limit of detection of such sensor systems, it is of high importance to understand and to be able to quantify the relevant noise sources. A straightforward approach to detect the desired phase information of SAW sensors is to compare the sensor output signal with a reference signal. In this paper, the effect of decorrelation of oscillator phase noise as a function of delay time and offset frequency is discussed and analyzed. An analytical expression is derived which describes the degree of phase noise suppression in heterodyne readout systems. The model is verified by various measurement series, showing a degree of phase noise suppression of -100 dB for an offset frequency of 1 Hz and for a decorrelation time of 1500 ns which represents a typical time delay of SAW sensors. Although the effect is analyzed with respect to SAW sensors, the results are basically applicable to all kinds of phase sensitive sensors.
Cited by 9
P.D. Rloch, E.G.S. Paige, M.W. Wagg · 1980
Cited by 1
H.C. Chan, Eric K. Hung · Defense Technical Information Center (DTIC) · 1999
An evaluation of the performance of the coherent sidelobe cancellation (CSLC) techniques in suppressing nighttime co-channel communications interference and ionospheric clutter in HF surface wave radars operating in coastal regions was carried out. In particular, the optimum order of execution among the three signal processing functions: (1) Doppler processing, (2) digital beamforming and (3) interference cancellation was of interest, in terms of signal-to-interference-plus-noise ratio (SINR) improvement and angular accuracy. The optimum order of execution between the above mentioned operations depends on the characteristics of the interference. In terms of ionospheric clutter, there is insufficient information to arrive at definitive conclusions. A preliminary examination of the temporal, spatial and spectral characteristics of ionospheric clutter was carried out to aid in the development of mitigating algorithms.
Cited by 7
Jianqing Ma, Qingchun Li · Procedia Earth and Planetary Science · 2011
The TT transform (Time-Time transform) is a new method to process non-stationary signal based on S transform, has a good ability of frequency conversion. The surface wave, with lower frequency compare with other seismic wave, can be suppressed through extracting the TT spectrum's diagonal elements of seismic data. However, this method has a deficiency that in pressing low-frequency signal, retaining a part of high-frequency interference that can be eliminated. But, the high-frequency interference can be removed by the S transform filtering. Therefore, a method of joint the S transform and TT transform to suppress surface wave is presented. Firstly, apply S transform time-frequency filtering for each trace seismic data to suppress the high frequency interference and random noise, and then, use TT filtering to suppress the surface wave with low frequency.
Cited by 2Open access
Shiqi Lv, Xiangbo Gong, Bin Hu et al. · IEEE Transactions on Geoscience and Remote Sensing · 2024
This article proposes a new surface wave suppression method based on nonsubsampled Shearlet transform (NSST). First, we use a frequency wavenumber (FK) Filter to extract surface wave noise from seismic data. We then apply a Shearlet transform to both the original data and the isolated surface wave, facilitating the creation of distinct Shearlet domain subbands characterized by diverse scales and directions. Next, we calculate the similarity coefficients between each corresponding subband of the original data and separated surface wave and use the standard deviation as the criterion for subband selection to enable adaptive selection. Then, mean thresholding and Bayesian separation algorithms are applied to suppress the surface wave components in the subbands. Finally, we integrate the selected subbands and perform an inverse NSST to reconstruct the surface wave-free seismic data. Replacing the traditional subband selection method with the adaptive method can effectively improve the efficiency of surface wave suppression, and the combination of mean value thresholding and Bayesian separation algorithm suppresses the surface wave noise in the subbands, resulting in high-quality reconstructed data.
Cited by 3