24 GHz RF-MEMS phase shifter with non-galvanic electromagnetic coupling fabricated in silicon-bulk technology

This contribution presents a Distributed MEMS Transmission Line (DMTL) phase shifter designed for 24 GHz and fabricated in Silicon-Bulk Micromechanic Technology. Using this technology enables to commonly suspend all capacitive loads on one movable plate and allows full range analog and homogeneous gap adjustment. The first available prototypes of the phase shifter are characterized to provide 5.4 °/mm differential phase shift at 24 GHz and to show 0.1 dB/mm insertion loss. An asymmetric coplanar signal coupler with a center frequency of 24 GHz and 10% bandwidth is used to contact the signal through the substrate of the phase shifter chip and back to a supporting printed circuit board. The normalized measured insertion loss of the coupling structure after simulated optimization is 0.13 dB - 0.17 dB.