Takeaki Shimanouchi

Single crystal silicon cantilever-based RF-MEMS switches using surface processing on SOI

This paper describes a novel structure and simple fabrication process for low-loss, low-cost, and high-yield RF-MEMS switches. Our switch has a single crystal silicon (SCS) cantilever, above which are located electroplated bridge electrodes on silicon-on-insulator (SOI) substrates. The fabrication process does not require any complex processes, such as wafer transfer, wafer backside etching, special planarization techniques, or low-stress thin-film formation. The fabricated series switch features a low-loss performance and small size. The overall insertion loss is -0.1 dB and the isolation is -30 dB at 5GHz. The size of the SP4T switch is 1.4 /spl times/ 0.9 mm/sup 2/.

A wireless motor-condition, precise analysis system using a highly efficient vibration-energy harvester

A wireless motor condition precise analysis system that uses a highly efficient energy harvester is described in this paper. A continuation data sampling is required for the condition analysis of a motor. We developed the technology that makes a vibration energy harvester highly efficient and reduces the energy consumption of the whole system. A battery-less wireless analysis system was created in which the operation and life prediction of a motor was made possible. The original structure of the highly efficient energy harvester was developed using magnetic strain material rods. Electric power is generated using the coils around the rods when the rods are bent by external vibration. Therefore, the efficiency of the energy harvester is raised by optimizing the internal stress of the rods using buffer plates. The energy harvester has a resonant frequency of 90 Hz, a maximum electromotive force of 2.7 V, and a maximum power of 28 mW using 0.5-G acceleration. The wireless motor condition monitoring system includes the energy harvester, an end device, a coordinator, and a PC for data processing. The end device for the monitoring and data transfer is operated using only the electric power from the energy harvester. The monitoring information on the temperature, humidity, supplied voltage, and communication quality every three seconds and for the vibration waveform every five seconds is transmitted to the coordinators by the end device and handled by the PC. This enables for the condition monitoring and fault prediction of the motor.

A sticking-free and high-quality factor MEMS variable capacitor with metal-insulator-metal dots as dielectric layer

This paper describes a novel design of a MEMS variable capacitor with high operating reliability and high quality factor. Metal-Insulator-Metal (MIM) dots between a fixed electrode and a movable electrode in a variable capacitor is proposed. A Fabricated MEMS capacitor was operated one billion or more times without sticking. It demonstrated a high quality factor of 200 at 0.5 pF. It was experimentally confirmed that MIM dots effectively achieve a sticking-free and high-quality-factor MEMS variable capacitor.

Effect of frequency in the 3D integration of a PZT-actuated MEMS switch using a single crystal silicon asymmetric beam

This paper presents the effect of frequency of radio frequency microelectromechanical system (RF MEMS) 3D integration with an actual device. A piezoelectric transducer (PZT)-actuated RF MEMS switch that uses a single crystal silicon asymmetric beam was designed, fabricated, and evaluated. We successfully drove a stiff beam (with spring constant >; 2,000 N/m) despite a low voltage (<;15 V). The switch lifetime was 4 × 107 cycles at low contact resistance and more than 1 × 109 cycles for the PZT actuator. The overall insertion loss and isolation were -0.3 dB and -25 dB, respectively, up to 5GHz. The effect of frequency of 3D integration was simulated with an RF MEMS switch and a ground plane placed over it. We discovered that a 3D IC comprising a control IC and an RF MEMS switch with a distance of more than 80 μm was successfully integrated.