Low Actuation Voltage DMTL Phase Shifter with Improved Reliability

A distributed MEMS transmission line (DMTL) phase shifter is designed using a novel tri-layer sandwich (Insulator-Metal-Insulator) membrane based shunt switch which results a reliable phase shifter and operates at a lower actuation voltage of nearly 16 V. Using combination of Bulk-micromachining as well as Surface-micromachining techniques, this phase shifter is fabricated on a high resistivity silicon substrate
$(\boldsymbol{p}=10,000\boldsymbol{\Omega}.\mathbf{c}\mathbf{m},\ \boldsymbol{\varepsilon}_{\mathbf{r}}=11.7$
, h=675 µm) and achieves a true-time delay operation from DC to 18 GHz. Measurements show a close match to the designed phase shifter with less than 1.7 dB of insertion loss (I.L.) and better than 14 dB return loss (R.L.) from DC to 18 GHz with an overall phase shift of 50.82 degree. This phase shifter can have wide applications in high-performance microwave and millimeter-wave integrated circuits in telecommunication, defense and space based phased array system, mobile satellite broadcasting communication etc.