RF MEMS switches for smart antennas

In this paper novel V-shaped and Z-shaped thermally actuated radio frequency (RF) MicroElectroMechanical Systems (MEMS) switches are designed and fabricated for the application of smart antennas. The switches are driven by a metal electrothermal actuator, which is able to generate large displacement and high contact force at lower temperatures. The MEMS switches utilizing the parallel beam actuator achieved 8 μm displacement. RF performances are improved by suspending the switching structures 25 μm above the substrate, thereby reducing the loss in the substrate. ON state insertion loss of −0.42 dB at 10 GHz, OFF state isolation of −40 dB at 10 GHz and return loss better than of −20 dB at 10 GHz for bidirectional Z-shaped thermally actuated RF MEMS switch are achieved on the low resistivity silicon substrate.