Qin Yuliang

Generation of OAM Beams Using Phased Array in the Microwave Band

A system is proposed to generate vortex electromagnetic (EM) beams in the microwave band, which generates high-order vortex beams at the X-frequency band for the first time. First, the orbital angular momentum (OAM)-generating system is designed and the signal model based on the uniform circular array is presented. Subsequently, the mathematical model with array error contributions is established and, comprehensively, numerical simulations are conducted to analyze how amplitude and phase errors affect the radiation field and the EM vortex imaging. The experimental results validate that the proposed system can readily generate vortex beams of high quality, which are in agreement with the simulated results. The work paves the way to applications of OAM-carrying beams as well as a novel information-rich radar paradigm.

A modified omega-K algorithm for missile-borne SAR imaging with the dive trajectory

This paper presents a novel approach for missile-borne SAR imaging with the dive trajectory using a refined omega-K algorithm (ωKA) to improve the focus performance. Based on a range model under accelerated dive trajectory, the characteristics of echo signal and two incidental problems with nonlinear dive aperture are analyzed. Then the modified ωKA with acceleration is designed to accommodate the dive flight while there is negligible increment of computation load compared with the original ωKA. Simulation results are also provided to validate the proposed imaging method.