3D Wide-Angle Beam-Scanning Compound Lens Using A Fast Hybrid Optimization Workflow

This paper presents a wide-angle beam-scanning 3D compound Gradient Index (GRIN) lens antenna designed with a highly efficient optimization workflow. Compound lenses offer improved scan loss over single-lens antennas through the addition of the second focal lens. The focal lens is close to a flat feed array and improves illumination efficiency by directing feed beams toward the center of the aperture lens. However, compound lens optimization is difficult due to high parameterization complexity and the need to simulate multiple feed positions. To address the optimization complexity, a novel hybrid optimization workflow is proposed, comprising a first stage of fast curved-ray Geometrical Optics (GO) and Particle Swarm Optimization (PSO), followed by a 2D Finite Difference Time Domain (FDTD) method, and finally validated in full-wave simulation. The proposed workflow exploits parallel computing and is capable of exploring a large parameter space and iterating over 50,000 candidate designs in 4 days (>500 large-scale simulations per hour). A demonstration compound lens antenna was designed and achieved a wide beam- scanning range up to ±55°, while maintaining a low frequency- averaged scan loss exponent of 2.25 across the Ka-Band.