Electrothermally Actuated RF MEMS Switches Suspended on a Low-Resistivity Substrate

Abstract

Abstract-This paper presents an electrothermally actuated lateral resistive-contact switch for application to low-gigahertz-band communication systems. It was manufactured on a standard low-resistivity substrate, and its RF performance was improved by suspending the structures 25 µm from the substrate, which is a strategy for future integration with active devices in the system-on-chip concept. Measured insertion losses are −0.26 dB at 1 GHz and −0.65 dB at 6 GHz, return losses are −29 dB at 1 GHz and −25 dB at 6 GHz, and isolations are −52 dB at 1 GHz and −26 dB at 6 GHz. The device is driven by a metal electrothermal actuator, which achieves large displacements and contact forces at much lower temperatures than traditional polysilicon electrothermal actuators. The RF power handling characteristics are also addressed and measured.[ 2007-0051]Index Terms-Electrothermal actuator, low-resistivity substrate, microelectromechanical systems (MEMS) switch, system on chip.

A novel electrothermally actuated RF MEMS switch for wireless applications

“…, where is the thermal expansion coefficient, k is the thermal conductivity, and E is the Young modulus, is better than polysilicon. Also, thermal expansion coefficient of nickel (see small inset in Table 1) is high compare with polysilicon, therefore exhibit same displacement at a lower temperature [7][8].…”

RF MEMS switches for smart antennas

“…where α is the thermal expansion coefficient, k is the thermal conductivity, and E is the Young modulus, is better than polysilicon. Also, thermal expansion coefficient of nickel as illustrate in Table 1 is high compared with polysilicon, therefore nickel beams are able to achieve same displacement at a lower temperature in comparison with polysilicon beams [D. Girbau et. al.…”

Electro-thermally actuated RF MEMS switch for wireless communication

“…MEMS technology is now rapidly emerging as an enabling technology to yield a new generation of high-performance RF-MEMS passives to replace these off-chip passives in wireless communication systems. [2] RF MEMS switches have great potential in being integrated into a RF system. Capacitive shunt switches have been mainly used at the frequencies above 10-15GHz [3], and lower frequency down to 7GHz [4].…”