Low Probability of Interception Beamforming in Single-Sideband Time-Modulated Antenna Arrays

2021 ◽  
Author(s):  
Haotian Li ◽  
Yikai Chen ◽  
Shiwen Yang
Keyword(s):  
Antenna Arrays ◽  
Single Sideband ◽  
Low Probability

Transmit Beamforming Based on 4-D Antenna Arrays for Low Probability of Intercept Systems

2020 ◽  
Vol 68 (5) ◽  
pp. 3625-3634
Author(s):  
Kejin Chen ◽  
Shiwen Yang ◽  
Yikai Chen ◽  
Shi-Wei Qu ◽  
Jun Hu
Keyword(s):  
Antenna Arrays ◽  
Transmit Beamforming ◽  
Low Probability ◽  
Low Probability Of Intercept

Object Wave Determination by Single-Sideband Methods

1973 ◽  
Vol 31 ◽  
pp. 266-267
Author(s):  
Kenneth H. Downing ◽  
Benjamin M. Siegel
Keyword(s):  
Phase Shift ◽  
Carbon Films ◽  
Object Wave ◽  
Electron Wave ◽  
Phase Object ◽  
Heavy Atoms ◽  
Single Sideband ◽  
Thin Carbon ◽  
Additional Phase Shift ◽  
Additional Phase

Under the “weak phase object” approximation, the component of the electron wave scattered by an object is phase shifted by π/2 with respect to the unscattered component. This phase shift has been confirmed for thin carbon films by many experiments dealing with image contrast and the contrast transfer theory. There is also an additional phase shift which is a function of the atomic number of the scattering atom. This shift is negligible for light atoms such as carbon, but becomes significant for heavy atoms as used for stains for biological specimens. The light elements are imaged as phase objects, while those atoms scattering with a larger phase shift may be imaged as amplitude objects. There is a great deal of interest in determining the complete object wave, i.e., both the phase and amplitude components of the electron wave leaving the object.

Specific Features Pertinent to the Use of Planar Antenna Arrays with Central Symmetry in Interference Cancellers

Vestnik MEI ◽  
2018 ◽  
Vol 2 (2) ◽  
pp. 123-128
Author(s):  
Pavel S. Gribov ◽  
◽  
Maria A. Gribova ◽  
Aleksandr Yu. Shatilov ◽  
◽  
...  
Keyword(s):  
Antenna Arrays ◽  
Central Symmetry ◽  
Planar Antenna

Influence of the Aperture Edge Diffraction Effects on the Mutual Coupling Compensation Technique in Small Planar Antenna Arrays

2011 ◽  
Vol 57 (1) ◽  
pp. 115-120 ◽  
Author(s):  
Mariusz Zamłyński ◽  
Piotr Słobodzian
Keyword(s):  
Antenna Arrays ◽  
Mutual Coupling ◽  
Planar Antenna ◽  
Sidelobe Level ◽  
Edge Diffraction ◽  
Narrow Angle ◽  
Compensation Technique ◽  
Diffraction Effects ◽  
Linear Antenna Arrays

Influence of the Aperture Edge Diffraction Effects on the Mutual Coupling Compensation Technique in Small Planar Antenna Arrays In this paper the quality of a technique to compensate for mutual coupling (and other phenomena) in small linear antenna arrays is investigated. The technique consists in calculation of a coupling matrix, which is than used to determine corrected antenna array excitation coefficients. Although the technique is known for more than 20 years, there is still very little information about how different phenomena existing in a real antenna arrays influence its performance. In this paper two models of antenna arrays are used. In the first model the effect of mutual coupling is separated from the aperture edge diffraction. In the second model antenna both mutual coupling and aperture edge diffraction effects are included. It is shown that mutual coupling itself can be compensated very well and an ultralow sidelobe level (i.e. -50 dB) could be achieved in practice. In the presence of diffraction effects -46.3 dB sidelobe level has been attained, but radiation pattern can be controled only in narrow angle range (i.e. up to ±60°).

Terrorism: Low probability, high consequence

1999 ◽  
Vol 55 (6) ◽  
pp. 14-16
Author(s):  
Diego Llumá
Keyword(s):  
Low Probability
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