Synthesis and Measurement of a Circular-Polarized Deflection OAM Vortex Beam With Sidelobe Suppression Array

Abstract

In this paper, a chamfer distribution antenna array is designed to generate a deflecting circular-polarized vortex beam carrying orbital angular momentum (OAM) mode. When the vortex beam is designed with a deflection angle, the sidelobe of the vortex beam will deteriorate. In order to solve this problem, an optimized array design is presented in this paper. Inspired by the Chebyshev distribution array synthesis method, the antenna elements in the four corners of the antenna array are cut out to realize the chamfer distribution array. Therefore, the sidelobe level of the deflected vortex beam can be effectively suppressed. Moreover, a simplified feeding network is designed to reduce the feeding network complexity by using circularly polarized structural center antenna element. The designed antenna array is simulated, fabricated, and measured at center frequency of 4.25 GHz in C-band. The far-field radiation pattern of the deflected vortex beam and the near E-field OAM vortex beam distribution are simulated and measured to verify the effectiveness of the proposed design method for sidelobe suppression array. INDEX TERMS Chebyshev array synthesis, chamfer antenna array, orbital angular momentum (OAM), sidelobe suppression, circular-polarized vortex beam.

Low‐sidelobe orbital angular momentum beam for donut‐shaped amplitude‐and‐phase metasurface based on Bayliss synthesis method

“…The I‐shape element is typically used to achieve amplitude and phase manipulation of cross‐polarized electromagnetic waves 14 . As illustrated in Figure 2A, the proposed modified I‐shaped element consists of a metal ground, a metal patch, and an F4B substrate ( ε r = 2.2, tan δ = 0.001).…”

“…The traditional array synthesis methods proposed for planar waves, such as Chebyshev synthesis, do not perform well when applied to suppress the SLL of OAM beams in APM. 13,14 Due to the pattern of the OAM beam exhibiting a typical null depth characteristic similar to the difference pattern, the Bayliss difference synthesis comes into view. However, since the divergence of OAM beams with the increase in mode order, the direct application of Bayliss synthesis for suppressing SLL is improved but generally limited.…”

“…The second is the determination of the amplitude distribution of APM. The traditional array synthesis methods proposed for planar waves, such as Chebyshev synthesis, do not perform well when applied to suppress the SLL of OAM beams in APM 13,14 . Due to the pattern of the OAM beam exhibiting a typical null depth characteristic similar to the difference pattern, the Bayliss difference synthesis comes into view.…”

Improved Side-lobe Suppression by Optimizing the Beam Synthetization in Uniform Circular Arrays for OAM Generation

“…Another example is when multiple beams are located at different places and interact after a certain distance (i.e., if there are arbitrary OAM superpositions), which leads to ambiguity between the beams [25]. To address this gap in OAM research, several techniques have been presented [26][27][28].…”

Circularly Polarized Antenna Array with Decoupled Quad Vortex Beams

“…Therefore, multi-mode vortex-beam generation devices would greatly meet the demand of improving spectrum efficiency [10]. Nowadays, various approaches to realize vortex waves have been proposed, such as single microstrip antennas [11][12][13][14][15], annular antenna arrays [16][17][18][19][20], traveling wave antennas [21][22][23][24], and metasurfaces [25][26][27][28][29][30], etc. However, generating multimode vortex beams simultaneously using microstrip array is still in its infancy.…”