Distributed transmission line phase shifter using MEMS switches and inductors

Distributed MEMS transmission line (DMTL) phase shifter has been developed using planar inductors. The design consists of a coplanar waveguide line capacitively and inductively loaded by the periodic set of electrostatic force actuated microelectromechanical system switches as capacitors and inductors. By applying a single bias voltage on the line, the characteristic impedance can be changed, which in turn changes the phase velocity of the line and creates a true time delay phase shift. The governing equations for the impedance and loss are derived. The ABCD matrix is defined for a unit and multi-cell DMTL phase shifter to extract scattering parameters equations. The device containing 15 cells calculated, simulated, and fabricated. Fabricated results show that the device can be considered as a new type of the DMTL phase shifter with small size, higher phase shift and acceptable scattering parameters.