scholarly journals On the Orbital Angular Momentum Incident Fields in Linearized Microwave Imaging

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1905
Author(s):  
Santi Concetto Pavone ◽  
Gino Sorbello ◽  
Loreto Di Donato
Keyword(s):  
Angular Momentum ◽  
Wireless Communications ◽  
Channel Capacity ◽  
Orbital Angular Momentum ◽  
Microwave Imaging ◽  
Next Generation ◽  
First Order ◽  
Rytov Approximation

Orbital angular momentum (OAM) is gaining great attention in the physics and electromagnetic community owing to an intriguing debate concerning its suitability for widening channel capacity in next-generation wireless communications. While such a debate is still a matter of controversy, we exploit OAM generation for microwave imaging within the classical first order linearized models, i.e., Born and Rytov approximation. Physical insights into different fields carrying ℓ-order OAM are conveniently exploited to propose possible alternative imaging approaches and paradigms in microwave imaging.

scholarly journals Modal coupling and crosstalk due to turbulence and divergence on free space THz links using multiple orbital angular momentum beams

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhe Zhao ◽  
Runzhou Zhang ◽  
Hao Song ◽  
Kai Pang ◽  
Ahmed Almaiman ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Atmospheric Turbulence ◽  
Channel Capacity ◽  
Orbital Angular Momentum ◽  
Beam Waist ◽  
Modal Coupling ◽  
Divergence Effect ◽  
Power Leakage ◽  
Calm Weather ◽  
Bad Weather

AbstractOrbital-angular-momentum (OAM) multiplexing has been utilized to increase the channel capacity in both millimeter-wave and optical domains. Terahertz (THz) wireless communication is attracting increasing attention due to its broadband spectral resources. Thus, it might be valuable to explore the system performance of THz OAM links to further increase the channel capacity. In this paper, we study through simulations the fundamental system-degrading effects when using multiple OAM beams in THz communications links under atmospheric turbulence. We simulate and analyze the effects of divergence, turbulence, limited-size aperture, and misalignment on the signal power and crosstalk of THz OAM links. We find through simulations that the system-degrading effects are different in two scenarios with atmosphere turbulence: (a) when we consider the same strength of phasefront distortion, faster divergence (i.e., lower frequency; smaller beam waist) leads to higher power leakage from the transmitted mode to neighbouring modes; and (b) however, when we consider the same atmospheric turbulence, the divergence effect tends to affect the power leakage much less, and the power leakage increases as the frequency, beam waist, or OAM order increases. Simulation results show that: (i) the crosstalk to the neighbouring mode remains < − 15 dB for a 1-km link under calm weather, when we transmit OAM + 4 at 0.5 THz with a beam waist of 1 m; (ii) for the 3-OAM-multiplexed THz links, the signal-to-interference ratio (SIR) increases by ~ 5–7 dB if the mode spacing increases by 1, and SIR decreases with the multiplexed mode number; and (iii) limited aperture size and misalignment lead to power leakage to other modes under calm weather, while it tends to be unobtrusive under bad weather.

Adaptive Optics Aided Orbital Angular Momentum Based Wireless Communications

2021 ◽  
pp. 1-1
Author(s):  
Huan Chang ◽  
Xiaoli Yin ◽  
Haipeng Yao ◽  
Jingjing Wang ◽  
Ran Gao ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Wireless Communications ◽  
Adaptive Optics ◽  
Orbital Angular Momentum

scholarly journals Microwave imaging of spinning object using orbital angular momentum

2017 ◽  
Vol 122 (12) ◽  
pp. 124903 ◽  
Author(s):  
Kang Liu ◽  
Xiang Li ◽  
Yue Gao ◽  
Hongqiang Wang ◽  
Yongqiang Cheng
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Microwave Imaging
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