Open AccessRadiation pattern synthesis for the generation of vortex electromagnetic wave
Author(s) -
Liu Kang,
Cheng Yongqiang,
Wang Hongqiang,
Li Xiang,
Qin Yuliang
Publication year - 2017
Publication title -
iet microwaves, antennas and propagation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.555
H-Index - 69
eISSN - 1751-8733
pISSN - 1751-8725
DOI - 10.1049/iet-map.2016.0681
Subject(s) - optics , physics , side lobe , radiation pattern , directivity , distortion (music) , angular resolution (graph drawing) , antenna (radio) , electromagnetic radiation , vortex , angular momentum , beam (structure) , beam steering , radar , radiation , amplitude , angular spectrum method , wavefront , computer science , telecommunications , diffraction , bandwidth (computing) , mathematics , amplifier , combinatorics , quantum mechanics , thermodynamics
Radiation pattern synthesis methods for the generation of orbital angular momentum (OAM) beams based on circular arrays are proposed. The concentric‐ring arrays are designed to suppress the side lobes of the radiation pattern firstly. Based on the genetic algorithm, two objective functions are defined to calculate the signal amplitude of each ring. Simulation results show that the proposed method can effectively suppress the side lobes, lower than −30 dB. Subsequently, for electromagnetic vortex imaging, the beam steering technique is applied to enhance the directivity of vortex beams for different OAM modes. Analyses indicate that large steering angle would lead to some distortion of the phase‐front distribution. Finally, the imaging model after beam optimisation is established and the sparse Bayesian method is exploited to image the target with high resolution. The work can benefit the generation of OAM‐carrying beams and its wide applications in radio communication and radar imaging.