Radio Frequency Micro Mechanical System (RF MEMS) switches are swiches that allow/block RF current/wave. They are actuated by electrostatic force between a ground plane and a suspended bridge, all are made of metals. When the bridge is up, the current is allowed to transmit through the transmission line (Fig. 1, left), whereas when the bridge is down, the current is directed to the ground (Fig. 1, right). In capacitive switches, there is a dielectric layer to prevent the ground plane and the bridge from direct contact (green layer in Fig. 1). My thesis focuses on this dielectric layer.
Fig. 1 - An RF MEMS switch in on-state (left, bridge up), and off-state (right, bridge down).
In experimental work, I characterized copper oxide film to see if it can be used in RF MEMS switches. The research found that CuO film is not an ideal material for RF MEMS switches, due to its surface roughness and its low dielectric strength. In parallel with experimental work, I have also carried out the analyses and simulations of CuO switches and found that bending, stretching and especially, residual stress have strong effects on mechanical behavior of the switches, particularly the pull-in voltage. The simulation and the analytical model could be helpful for designing and optimizing RF MEMS switches .
The thesis can be downloaded using this link.