Micro electromechanical RF switch

Abstract

Abstract A micro electromechanical RF switch is fabricated on a substrate (12) using a suspended microbeam as a cantilevered actuator arm (20). From an anchor structure (14), the cantilever arm (20) extends over a ground line (16) and a gapped signal line (18) that comprise microstrips on the substrate. A metal contact (22) formed on the bottom of the cantilever arm remote from the anchor is positioned facing the signal line gap. An electrode (24) atop the cantilever arm forms a capacitor structure above the ground line. The capacitor structure may include a grid of holes extending through the top electrode and cantilever arm to reduce structural mass and the squeeze damping effect during switch actuation. The switch is actuated by application of a voltage on the top electrode (24), which causes electrostatic forces to attract the capacitor structure toward the ground line (16) so that the metal contact closes the gap in the signal line (18). The switch functions from DC to at least 4 GHz with an electrical isolation of -50 dB and an insertion loss of 0.1 dB at 4 GHz. A low temperature fabrication process allows the switch to be monolithically integrated with microwave and millimeter wave integrated circuits (MMICs). The RF switch has applications in telecommunications, including signal routing for microwave and millimeter wave IC designs, MEMS impedance matching networks, and band-switched tunable filters for frequency-agile communications.

Inventors

• 👤 Jason Yao Jun

Bibliographic Details