A Novel Method for High Resolution RADAR Imaging by Orbital Angular Momentum Interferometry

Inhalt:
The aim of this work is to give a proof of concept for high-resolution radar imaging using the Orbital Angular Momentum (OAM) communication channel for designing static, i.e. non-moving, electromagnetic sensors. To achieve this goal we design an interferometic imaging system constituted by two fixed sources separated by a given spatial baseline and used for range-azimuth synthesis. Here we also present the design of a planar vortex antenna, tailored for radar imaging application, transmitting ”ad-hoc“ structured wave packets using an incremental stepped chirp strategy and with single-mode OAM linearly incremented modulation. In order to test the imaging performance we assign the resolutions of each range-azimuth dimension to the OAM bandwidth used to synthesize the phase ripple. Moreover we develop a novel method for the synthesis of multi-modal transmissions by integrating several single-modes OAM transmissions. The OAM raw data are focused through fast-Fourier transform (FFT), and range-azimuth radar spatial resolutions depend on the OAM value and the stepped frequency chirp bandwidths.