Multi-Band Hybrid ISAR Simulation: Addressing Photonic and EM Fidelity from X-band to W-band

We present a multiphysics simulation framework for a photonic inverse synthetic aperture radar (ISAR) system operating across X-, Ku-, and W-bands. The approach integrates electromagnetic and photonic domains to evaluate high-frequency imaging fidelity under realistic system conditions. A hybrid electromagnetic model combines global Physical Optics (PO) with localized two-dimensional Finite-Difference Time-Domain (FDTD) corrections to capture both large-scale reflections and fine-structure scattering near edges and junctions. The photonic front-end is modeled with Mach–Zehnder modulator nonlinearities, laser relative-intensity noise, fiber dispersion, and atmospheric attenuation based on ITU-R P.676-12. Simulations demonstrate progressive improvement in spatial resolution—from 10 cm at X-band to 1.5 cm at W-band—while revealing the increasing influence of photonic distortion and atmospheric loss at higher frequencies. The hybrid PO–FDTD coupling accurately restores fidelity in critical scattering regions without the computational expense of full-wave 3D solvers. This work establishes a practical tool for designing and validating next-generation photonic ISAR systems spanning multiple radar bands.