Modal beamforming array gain

1989 ◽  
Vol 85 (1) ◽  
pp. 146-151 ◽  
Author(s):  
T. C. Yang
Keyword(s):  
Array Gain

scholarly journals Array Gain of a Linear Array in an Ocean Waveguide

2021 ◽  
Vol 11 (11) ◽  
pp. 5046
Author(s):  
Zong-Wei Liu ◽  
Chun-Mei Yang ◽  
Ying Jiang ◽  
Lei Xie ◽  
Jin-Yan Du ◽  
...  
Keyword(s):  
Transmission Loss ◽  
Spatial Coherence ◽  
Correlation Coefficients ◽  
Channel Correlation ◽  
Acoustic Channel ◽  
Physical Mechanisms ◽  
Channel Characteristics ◽  
Special Case ◽  
Array Gain ◽  
Insight Into

Array gain is investigated based on the acoustic channel characteristics manifested by the fluctuant transmission loss and decrease in the acoustic channel spatial coherence. An analytical expression is derived as the summation of the products of the acoustic channel correlation coefficients and root-mean-square pressures. The formula provides insight into the physical mechanisms of the gain degradation in the ocean waveguide. Furthermore, this formula provides a new method to study array gain in the ocean waveguide from underwater acoustic field. The obtained expression is a more general formula that is applicable to shallow water, deep sea, and continental slope, with the traditional methods as a special case. Numerical results show that the array gain calculated by previous formulas are generally overestimated, caused by ignoring the effect of transmission loss fluctuation.

Second Difference Electron Energy-Loss Spectroscopy with the Gatan Imaging Filter

1999 ◽  
Vol 5 (S2) ◽  
pp. 808-809
Author(s):  
E.C. Buck
Keyword(s):  
Nuclear Waste ◽  
High Frequency ◽  
Waste Materials ◽  
White Line ◽  
Minor Elements ◽  
Gain Variation ◽  
Line Absorption ◽  
Electron Energy Loss ◽  
Frequency Features ◽  
Array Gain

The large number of minor elements present in geological specimens and nuclear waste materials, can make TEM/EDS analysis of such samples troublesome. With a parallel detector such as the Gatan PEELS 666, the second difference technique has been shown to be effective at removing the channel-to-channel gain variation [1]. As spectroscopy performed with the Gatan Imaging Filter (GIF200) averages over a 2D array, gain variations are minimal; however, the second-difference technique selectively enhances the high frequency features such as the “white line” absorption edges, particularly of rare earth elements (REE) and transuranics (TRU). The second difference method may thus still have merit with the GIF200. A script was created within the controlling software program (DigitalMicrograph ™) which permitted second difference acquisition [2]. The Spectroscopy Package was also modified with ResEdit and the required values were added to the Global Tags to enable easy application of the second difference routine.

Reduced-Dimension MUSIC for Angle and Array Gain-Phase Error Estimation in Bistatic MIMO Radar

2013 ◽  
Vol 17 (3) ◽  
pp. 443-446 ◽  
Author(s):  
Jianfeng Li ◽  
Xiaofei Zhang ◽  
Renzheng Cao ◽  
Ming Zhou
Keyword(s):  
Error Estimation ◽  
Phase Error ◽  
Mimo Radar ◽  
Bistatic Mimo Radar ◽  
Reduced Dimension ◽  
Array Gain

scholarly journals Array Gain Analysis in Molecular MIMO Communications

IEEE Access ◽  
2018 ◽  
Vol 6 ◽  
pp. 61091-61102 ◽  
Author(s):  
Martin Damrath ◽  
H. Birkan Yilmaz ◽  
Chan-Byoung Chae ◽  
Peter Adam Hoeher
Keyword(s):  
Mimo Communications ◽  
Array Gain

scholarly journals Theoretical and experimental study on a finite size vector sensor array with a cylindrically symmetric carrier

2019 ◽  
Vol 283 ◽  
pp. 07008
Author(s):  
Junyuan Guo ◽  
Shi-e Yang ◽  
Hongjuan Chen ◽  
Shengchun Piao ◽  
Longhao Qiu
Keyword(s):  
Finite Size ◽  
Low Frequency ◽  
Doa Estimation ◽  
Radial Component ◽  
Tangential Component ◽  
Low Frequencies ◽  
Cylindrically Symmetric ◽  
Noise Characteristics ◽  
Vector Sensor ◽  
Array Gain

In this work, a finite size acoustic vector sensor (AVS) array is designed and its performance is theoretically and experimentally studied. The two-dimensional AVS array is comprised of five vector sensors and configured as a cross, and the array carrier is a cylindrically symmetric structure. Theoretical analysis and simulation indicate that the proposed method considering structure scattering can widen the working bandwidth. Furthermore, the utilization of vector sensor enables a significant white noise gain improvement at low frequencies, which makes the array more robust and easier to realize. Experiments have been done to study the array performance from several aspects including sensor noise characteristics, the beampattern, the direction-of-arrival (DOA) estimation ability and the array gain. From the change of the sensor directivity patterns or the amplitude distortion of the noise field, we can clearly observe the scattering field intensity. Moreover, it shows that the influence of the structure scattering on the tangential component of the vector field is symmetric, while that of the radial component is asymmetric. Experimental results also demonstrate that, with the proposed method, the 2nd and the 3rd order beamformers can be obtained which could be further used for the estimation of target DOA. In addition, an array gain of at least 6 dB is obtained capable of detection of weak signals. Our results indicate that the proposed array with a physical size less than one meter, although affected by nearby scatterers, can effectively break the Rayleigh limit and realize the remote detection in low-frequency regime.

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