Papers by Keyword: Capacitive

Abstract: Capacitance induction makes touch technology become more intuitive, can detect multiple fingers and at the same time to recognize gestures. This paper will introduce basic principle of capacitance induction and capacitance sensing technology in automotive applications. In this article introduces the structure of multi-touch screen and internal operations will be discussed after multi-touch induction to the change of human-machine interface (HMI).

Abstract: Low frequency performance of geophone is important when using microtremor system to explore deep geological structure. This paper reports on improving low frequency performance of a geophone by measuring the capacity attached on a conventional geophone, and the consistency of geophone can be adjusted. The design, principal, and performance of the capacitive position sensing geophone are presented. A prototype geophone is designed and manufactured in the laboratory.

Abstract: Microwave absorbing properties of composites containing activated carbon-fiber felt screens (ACFFSs) have been investigated. Samples with different types of ACFFSs embedded in composites were fabricated. Experiments were carried out to test the absorption effect of embedded ACFFSs. It is found that both the ACFFS patterns and its element configurations are critical for the reflection properties of samples. With the distance between strips and the width of strips in the inductive ACFFS decreased, the absorbing properties of composites are improved. The composite obtains a reflection loss below –10dB in 8~18GHz, which is the frequency range the radar works in, when the distance between strips and the width of strips are 7mm and 5mm respectively. With the side of plates and the distance between plates in the capacitive ACFFS reduced, the absorption effect of composites rises. When the distance between plates and the side of plates are 5mm and 7mm separately, the composite achieves a reflection loss below –10dB over a bandwidth of 8.7GHz and the minimum value of absorption rate reaches –31.7dB.

Abstract: This paper reports the design of an optimal controller to prevent suppressvertical vibration due to undesired out of plane excitations generated by environment or gripper during manipulation for a CMOS-MEMS Nano-Newton capacitive force sensor applied for biomedical applications. Undesired out of plane excitations generated by environment or gripper during manipulation is the most prevalent source of vertical vibration in this type of sensors. To suppress the vibrational movement a PZT 5A is used as actuation mechanism. Discrete element method DEM model and Modal analysis were used to find dominant natural frequencies and mode shape vectors. To eliminate out of plane excitation an optimal linear quadratic regulator is proposed using By State-Space formulation. Simulation results illustrate that by employing optimum LQR control approach the maximum disturbance input is suppressed less than 0.7 sec with acceptable range of control voltage amplitude.

Abstract: An accelerometer is a micro- electromechanical device which can sensitive to acceleration . The sensing mechanism of accelerometer is that when accelerated , the mass moves in Z-axis, and the gap between parallel plates changed with the loads, which causes vary of the capacitance of the estimation. This paper presents a newly devel oped sensor for the conventional capacitive MEMS accelerometer in Z-axis . The principle of capacitive acceleration is based on the detection the change of capacitance which results from acceleration changes. The sensor is used for estimation of the size a nd loads variations for accelerometer. This paper has been focused on the design of the MEMS accelerometer and calculation of the major parameters of the sensor.

Abstract: We report two improvements of our all-silicon carbide (SiC) micromachined capacitive diaphragm-based pressure sensors: Ti/TaSi2/Pt contact metallization to enhance temperature cycling durability and a 0.5 μm-thin sensing gap to further improve sensor sensitivity. Three sensors with 0.5 μm and 1.5 μm sensing gaps were packaged individually in high temperature ceramic packages and characterized to designed (static) pressures of 2.1 MPa (300 psi), 3.4 MPa (500psi) and 6.9 MPa (1000 psi) up to 550°C. For the 3.4 MPa range sensor (0.5 μm gap, 70 μm diaphragm radius), a sensitivity of 0.06 fF/Pa and a nonlinearity of 2.0% was obtained at 550°C in contact mode operation. In comparison, the 2.1 MPa range sensor (1.5 μm gap, 95 μm diaphragm radius) demonstrated a sensitivity of 0.07 fF/Pa and a nonlinearity of 4.6% at 550°C in contact mode operation. The 6.9 MPa range sensor (1.5 μm gap, 70 μm diaphragm radius) demonstrated a sensitivity of 0.03 fF/Pa and a nonlinearity of 4.0% at 500°C, also in contact mode.

Abstract: The Sensor and Circuit of testing fabric infiltrate characteristic are designed. By testing capacitance variation ΔC between the sensor and two plates. It can detect the spread of area of the fabric seepage ΔS and determine the seepage rate of the tested fabric. The Calibration testing has been achieved for the Sensor and Circuit. The data is given out. The linear distortion of the testing Sensor and Circuit is smaller than 5%.It can meet the technical requirements of the testing seepage characteristics of textile products.

Abstract: A monolithic MEMS accelerometer process was established. This process successfully combines our standard BiCMOS technology and MEMS surface micromachining technique. The acceleration sensing element is a kind of comb-finger structure which is built by polysilicon surface micromachining technique. The polysilicon structure is designed to form two capacitors for acceleration sensing. The external acceleration will cause the value of two capacitors to vary in different direction. That means one reduces if the other increases. It was integrated with the signal conditioning circuit. In a single die, the active devices including vertical NPN, lateral PNP, PMOS and passive devices such as capacitors, resistors were fabricated which was followed by the steps to form the acceleration sensing structure. The experiment indicates that the fabricated circuit has the function of sensing capacitive variation and with a scale factor of 100mV/g.

Abstract: This paper proposes a sophisticated type of capacitive clamped beam RF MEMS power sensor, which is fabricated on GaAs substrate with MMIC technology. This new capacitive clamped beam RF MEMS power sensor can act quickly to the RF signals and consumes little power on central CPW line. A version of draft microwave circuit model is presented, in order to build a set of initial structure parameters of the clamped beam RF MEMS power sensor simulation model. The frequency scope of this designed clamped beam RF MEMS power sensor is from 8GHz to 12GHz. Through adjusting the set of initial structure parameters of simulation model, a set of successful and proper S parameter of HFSS simulation can be obtained, and the S parameter is: S11 is less than -35dB and S21 is less than 0.15dB. Based on the performance parameter mentioned, the optimization on the power sensor simulation structure has been presented.

Abstract: This paper presents a lateral thermally-actuated and laterally capacitive shunt MEMS switch utilizing parylene as the dielectric layer. The bulk maicromachined switch consists three parts which, including coplanar waveguide (CPW) line, switching plates and thermally actuated structures. Measured results show that the threshold driving voltage and current of the proposed switch are 11.5V and 95mA, the single side and both side isolations at close-state are 7.7dB and 10.2dB at 18GHz when parylene thickness is 530nm, respectively. With 80nm- thick parylene, the single side and both sides isolations are 11.2dB and 15.7dB at 18GHz, respectively. The insertion loss at open-state is below 0.26dB up to 18GHz, when a boding wire is used to bridge the ground line.