Jin Zhong-he

Thermally excited micromechanical vacuum resonator

A micromechanical resonator is proposed and realized. It consists of a single-crystal silicon beam and two P-type silicon resistors. One resistor is used to excite the vibrating beam and the other to sense vibration of the beam. The dimensions of the resonator are about 4/spl times/2.5 mm/sup 2/, the resonant frequency is about 7.8 KHz, Q factor about 190 in air and above 2500 in vacuum degree of 7.5/spl times/10/sup -4/ Pa. The theory of thermal excitation is analyzed and the characteristics of the resonator are tested. We conclude that the resonator can be applied to vacuum measurement by the means of closed-loop resonating circuit. The design and realization of the circuit are described.

Discussion on the optical-coupling in silicon optical-type micromechanical sensors

A flow-sensor and a resonator are fabricated on silicon substrate using the micromechanical technology. The devices are with a structure based on a silicon cantilever with waveguide on the surface to detect the movement of the silicon cantilever. The method to couple the laser into the waveguide is discussed and the performance of the fabricated devices are characterized.

Analysis of a MEMS gyroscope interface circuit

The interface circuit of a MEMS gyroscope is analyzed in this paper. The gyro works at atmospheric pressure, driven by electronic magnetic force, and sensed by capacitance. The equivalent models of the gyro and the circuits are set. The performance of the gyro system is analyzed and optimized with the model. As a result, the system performance is significantly improved. The gyros resolution reaches 0.05 /spl deg//s, with full scale value 150 /spl deg//s, scale factor 9.8 mV/( /spl deg//s), nonlinearity 0.43%, and bias drift 3.06/spl deg//s /h.

A NOVEL STRUCTURE OF ALL-OPTICAL TYPE SILICON MICRORESONATOR

A novel All-Optical type Silicon MicroResonator (AOSMR), with exciting and testing optical fibers is reported in this paper. It consists of a ridge optical waveguide and input and output optical fibers to pick up vibrations. The advantages include simplicity in structure and convenience in operation. Both theoretical analysis and experimental results showed that the new structure has large misalignment tolerance between the fiber and vibrator. The optical length of the fiber does not affect the output signal. In addition, the resonant frequency of the vibrator is independent of the internal stress of the silicon wafer.