Ground speed Doppler sensor with a micromachined double folded slot antenna

This paper presents a new concept for the Doppler sensor for true ground speed measurement. The basic principle is based on a membrane supported double folded slot antenna operating at 77 GHz with a bidirectional radiation characteristic and a Schottky diode for signal mixing and Doppler frequency shift extraction. The sensor was fabricated using silicon micromachining. A dedicated setup was used for the proof of concept and the Doppler spectrum was recorded for different moving surface speeds. The measurement error is less than 2 % for speeds between 1 and 3 m/s.