In this paper, we propose a kind of variable scale aperture sampling reception (VSASR) method for multiple orbital angular momentum (OAM) modes vortex wave reception and demodulation. The VSASR method overcomes the restrictions of equal interval OAM modes which is necessary for the existing partial aperture sampling reception method for keeping the OAM modes orthogonality. Thus, it has higher OAM modes multiplexing utilization efficiency than the partial aperture sampling reception method at the same reception aperture. It is also well for vortex wave consistency reception. Although the orthogonality is a little damaged and there are some other crosstalk OAM modes, the main transmission OAM modes can be kept and distinguished by introducing some specific digital signal processing methods. Finally, for a verification of the presented VSASR method, several reflective metasurface antennas working at 10 GHz are designed, fabricated, and measured to generate different OAM vortex waves. Both the electromagnetic simulation and the measurement experiments are consistent well with the proposed theory analysis, which demonstrates the correctness and effectiveness of the proposed method.

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.

This paper proposes a new solution to multi-target joint detection, tracking and classification based on labeled random finite set (RFS) and belief function theory. A class dependent multi-model marginal generalized labeled multi-Bernoulli (MGLMB) filter is developed to analytically calculate the multi-target number, state estimates and model probabilities. In addition, a two-level classifier based on continuous transferable belief model (cTBM) is designed for target classification. To make full use of the kinematic characteristics for classification, both the dynamic modes and states are considered in the classifier, the model dependent class beliefs are computed on the continuous state feature subspace corresponding to different dynamic modes and then fused. As a result that the uncertainty about the classes is well described for decision, the classification results are more reasonable and robust. Moreover, as the estimation and classification problems are jointly solved, the tracking and classification performance are both improved. In the simulation, a scenario contains multi-target with miss detection and dense clutter is used. The performance of multi-target detection, tracking and classification is better than traditional methods based on Bayesian classifier or single model. Simulation results are illustrated to demonstrate the effectiveness and superiority of the proposed algorithm.