RF MEMS phase shifters for 24 and 77 GHz on high resistivity silicon

Beam steering is a common technique within radar applications to scan for objects within a small dihedral angle. A flexible approach to achieve this uses variable phase shifters in front of each single antenna in an array. This paper presents delay line phase shifters for two common radar frequencies in the K and W-band of 24 and 77GHz. The active components are capacitive RF MEMS switches. These were fabricated on high resistivity silicon using metal thin film technologies. The performance of the phase shifters, especially the insertion losses of around 2.3 and 3 dB can compete with diode switched setups on other RF substrates.