Dielectric Lenses for 120-GHz Radar Front End Board

Sammanfattning

Radar systems are versatile technologies that have multiple applications spanning military, automotive and space domains. A key component of the radar systems is the antenna, and its directivity plays a crucial role, which is its capability to focus the electromagnetic (EM) energy onto the target. The radar considered in this thesis is a radar front-end (RFE) board, which consists of a transceiver chip that has two dipole antennas. The antennas exhibit a non-directive radiation pattern. The intended approach to improve the radiation pattern is to integrate the radar feed with a dielectric lens. The lens design is carried out using an in-house Ray Tracing tool (RT). The tool consists of three steps: Geometric Optics (GO) in which the cylindrical waves are modeled as rays; Ray Tube Theory, which computes the electric field amplitude distribution at the lens aperture; and Kirchoff’s diffraction formula, which determines the far field radiation pattern of the antenna. The tool allows flexible lens geometry design and has the provision to import the radiation pattern of the feed obtained from solvers such as CST Studio or COMSOL Multiphysics. A comprehensive study on parameters was conducted to establish an efficient RT setup for the lens design to improve the radar’s radiation pattern. Plano-convex lens geometry using conic and spline formulations was investigated to identify configurations that can improve the radiation pattern. The results were then verified using CST Studio.