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ARL scientists develop fabrication method for RF MEMS switches with longer lifespans that function with low actuation voltages. The patented technology is available via license agreement to companies that would make, use, or sell it commercially.
The micro-electro-mechanical systems (MEMS) industry has used piezoelectric thin films for use as micro relays or as radio frequency (RF) MEMS switch actuators. Other micro relay devices utilize a sol-gel lead zirconate titanate (PZT) thin-film actuator to close a direct current contact. These RF switches are components incorporated into larger devices, such as RF phase shifters.
Conventional MEMS switches have not been satisfactory for higher frequencies because of impedance miss-match problems and other perturbations to RF propagation. The traditional designs also require relatively large actuation voltages for proper functioning and have reduced device lifetimes. Thus, there remains a need for an RF MEMS switch with increased device lifetime that is also capable of functioning under low actuation voltages.
ARL researchers have developed a piezoelectric in-line RF MEMS switch and a corresponding method of fabrication for both a series switch configuration and a shunt switch configuration. The switch turns RF signals on and off that are propagating along a coplanar waveguide (CPW) configured RF transmission line. Preferably, the RF transmission line comprises a pair of CPW ground planes flanking the RF conductor and several ground straps, so the RF transmission line can provide a path along which RF signals propagate.
The starting material for the device is a single crystal silicon wafer with a silicon dioxide coating created by plasma-enhanced chemical vapor deposition. Photolithography is then used to define the switch structure and etch patterns into the silicon dioxide coating.
- Increases device lifetime
- Functions with low actuation voltages
- Fabrication method works for both series switches and shunt switches
- Businesses can commercialize the technology by licensing U.S. Patent 7,518,474 from the Army
- This U.S. Patent 7,518,474 is related to U.S. Patent 7,532,093
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