Flexible Radar Front End with Multimodal Transition at 300 GHz

Especially for short-range radar sensors, a protection of the electronics against environmental damage like heat or humidity as well as a robust antenna front end are essential. In order to separate the sensitive electronics and the robust antenna spatially, a system concept for a 300-GHz radar with mechanically flexible front end is presented in this paper. The flexible front end is realized with a low-loss dielectric waveguide (DWG) with losses of around 15 dB/m. It is bendable up to a radius of 1 cm. An elliptical lens (30.9 dBi) at the end is used to focus the beam. The front end is fed by a radar MMIC in a QFN-like package with an integrated silicon lens. The wide beam is focused by simply placing a multimodal DWG above package and lens. The intentionally caused interference of the individual modes then results in a field maximum in the center, and the fundamental mode can be fed into the DWG.