THz Phase Shifter based on MEMS-actuated Slot Waveguides

We present a THz phase shifter with electrostatic actuators modifying the dimensions of a slot waveguide. The slot waveguide is held by mechanical metamaterials whose structural characteristics are much smaller than the wavelength to prevent a reduction of the field confinement. CST Microwave Studio simulations show that the variation of the slot width changes the phase of the feeding wave achieving a phase shift of more than 360 degree at 300 GHz. We show how to combine a slot waveguide demanding high resistive silicon with electrostatic actuators requiring p-doped silicon by using a special SOI design and fabrication process. During electromechanical characterization of the slot waveguide the actuators successfully alter the slot voltage-dependently in the range between 46.4 µm and 182.4 µm using up to 70 V.