Synthesis for OAM Vortex Electromagnetic Waves Based on Fourier–Bessel Expansion

Synthesis of Orbital Angular Momentum Antennas for Target Localization

“…To test the proposed approach in this scenario, we adopted the same identical array layout, single‐element pattern, and working frequency as the ones in Yu and Kou (2023). Furthermore, although our approach achieves the best results for $$\hat{\mathscr{l}}=1$$, we set $$\hat{\mathscr{l}}=2$$ as it was done in Yu and Kou (2023) in order to come to a perfectly fair comparison.…”

“…This time, differently from the comparison with (Kou & Yu, 2022), no further optimization of the excitations has been performed. This procedure led to an excitation amplitude per ring equal to {−18.50, −10.72, −5.98, −2.49, −0.83, −0.04, 0.00, −0.63, −1.97, −3.96, −6.73, −10.34, −14.98, −21.12, −28.52} dB, which has been rounded by using the same significant digits as in Yu and Kou (2023) before computing the far field. As far as the elements' excitation phase is concerned, we used the same values as the ones exploited in Yu and Kou (2023) so that, in the end, the unique difference between the two numerical experiments is the elements' excitation amplitude.…”

“…Notably, once the optimal continuous source has been identified, step (ii) can be performed by adapting to the present case equations or algorithms that have been previously developed. Therefore, the discussion of this step is postponed to the following Section, where the discretization of the reference continuous distribution will be separately outlined by presenting different array-design applications as well as comparisons with the techniques proposed in Kou and Yu (2022) and Yu and Kou (2023).…”

“…Then, applications involving different ways of discretizing the continuous aperture distributions are investigated. In particular, in Section 4.2, we compare the proposed approach with the techniques recently published by Kou and Yu (2022) and Yu and Kou (2023) for the synthesis of equispaced circular-ring arrays. Then, in Section 4.3, we address the design of an isophoric sparse ring array (which is then also full-wave simulated in Section 4.5).…”

“…Performance Parameters Comparison Between the Proposed Approach and the One inYu and Kou (2023) The presented technique allowed a significant improvement of the sidelobe level by using the same array layout and OAM vortex order.…”