Figure 9- - uploaded by Mario Ricardo Gongora Rubio
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Block diagram of sensor associated electronics As the amplifier for the Colpitts oscillator a wide band (IF) intermediate frequency amplifier having AGC was used, this circuit can be an easily added feature to the sensor package.
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![Figure 1-Ceramic technologies comparison [13]](profile/Mario-Gongora-Rubio/publication/241552954/figure/fig1/AS:670047567618075@1536763197804/Ceramic-technologies-comparison-13_Q320.jpg)
Non-contact displacement sensors are generally grouped in three categories: eddy current, capacitive and optical sensors. Eddy current proximity sensors, in particular ceramic ones, could be used in many industrial applications because their ability to work in harsh environments. In this paper we discuss a novel approach of implementing 3D multilay...
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Context 1
... have used A single layer coil model as proposed by [9], [11] and modified to include interlayer capacitances to obtain multilayer model as shown in figure 3.We found good agreement of SPICE simulations with experimental results shown in figure 9. ...
Context 2
... shown in figure 2, the proximity sensor is driven with a Colpitts oscillator in order to generate a frequency output proportional to displacement. We used in the present design a Colpitts oscillator incorporating an AGC (Automatic Gain Control) circuit with a block diagram as depicted in figure 9. ...
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Citations
... The footprint of the sensor influences the sensing range: larger coils inspect a greater volume of material from any given position, since the magnetic field flows deeper into the measured object, while smaller coils are more sensitive to defects. A 3D planar non-contact proximity sensors fabricated using LTCC technology is presented in [132]. The sensor has a footprint of 10 × 10 mm and is built up using the DuPont 951 material system. ...
Low Temperature Co-fired Ceramics (LTCC) is one of the microelectronic techniques. This technology was initially developed as an alternative to Printed Circuit Boards (PCB) and classical thick-film technology, and it has found application in the fabrication of multilayer ceramic boards for electronic devices. Fast and wide development of this technology permitted the fabrication of 3D mechanical structures and integration with various different processes. Thanks to this, LTCC has found application in the manufacturing of various microelectronic devices. This paper presents an overview on LTCC technology and gives a detailed summary on physical quantity sensors fabricated using LTCC technique.
... This results in large resistances and therefore a limitation of the quality factor. If high quality factors are required, large dimensions for planar coils must be accepted due to high sheet resistivity [4,5]. A molding of the sensor coil layout into a ceramic multilayer substrate via embossing combined with a photolithographic process was used to overcome the dependency between conductor thickness and line resolution. ...
Proximity and position measurements with eddy current sensors are limited by the quality factor of the sensing coils. By enlarging the conductor path cross section, the quality factor can be increased. On ceramic multilayer substrates such cross sections, which are considerably larger in comparison to screen printed thick films, can be manufactured with an embossing and filling procedure, which is integrated into the conventional fabrication process. The conductor path layout is molded into the unfired ceramic substrate prior to filling the trenches completely with the conducting paste, thus generating a large cross section. This technique is applied for the sensing coil of an eddy current sensor. The higher quality factor leads to a doubled sensitivity in comparison to conventionally screen printed sensors. Due to the thermal and chemical durability of the ceramic substrate, the coils can be directly applied in a variety of harsh environment conditions, such as in situ engine monitoring.
... LTCC technology has been recently used for various types of physical sensors measuring e.g. temperature, distance, force, pressure, and mass flow [1][2][3][4][5]. Typically the measurement of force or pressure is based on the deformation of integrated parts of the sensor substrate which can be detected electrically by piezoresistive, piezoelectric, or even optical transducers [3][4]. ...
State of the art in mechanical elements of MEMS in LTCC-technology are diaphragms and beams, e.g. for force and pressure sensors. These elements perform small strains and small deformations under loads. However a lot of sensor and actuator applications require movable elements that allow higher deformations whereas the local strains are still low. Such applications are e.g. springs, accelerometers, actuators, positioners, and valves. For an accelerometer we developed an approach for the fabrication of leaf springs integrated into the LTCC technolo-gy. The working principle of the accelerometer is based on a seismic mass disposed on two parallel leaf springs which carry piezoresistors connected to form a measuring bridge. In a first design optimization step, we used a FEA model for finding an optimized design conforming to our sensitivity requirements, inclusive of resonance frequency. In a second step, we performed a tolerance analysis that calculates the probability distributions of functional variables from the probability distributions of the design parameters. This enables the probability of a system failure to be deduced. In a final design step, a design of the ceramic thick film accelerometer was calculated that minimizes the system failure propability. As a result we obtained a design optimized with con-cern to a set of functional requirements and design tolerances. The results of the computations using the FEA models were compared to results of measurement data acquired from prototypes of the accelerometer.
... @BULLET Special pattern and structure of coil. Compared with traditional winding coil LTCC can include printed conductor (like coil) and provide an excellent way to obtain rapid prototype with the requirement from customer [6]. @BULLET Compatibilities with electronic signal Low internal capacitance allows to apply high frequencies in the passive component in the associated electronics. ...
In the future increasingly more sensors will be used for the control of engines. To that purpose positions, velocities or accelerations of moving components will have to be monitored in very harsh environments. In our work an electromagnetic sensor based on the eddy current principle has been designed. Most of the simulations of the physical behavior were performed using the finite-elements program ANSYS. In a first step the sensor’s geometry and its mounting position were adapted to the shape and motion of the component. To that purpose, a modal analysis of the part was performed. In a next step the sensor’s function was evaluated and the sensitivity to be expected was computed. Furthermore the functional optimization yielded the optimum electrical parameters for the subsequent circuit design. In addition to these optimizations the finite elements software was also used for an improvement of the assembly and packaging technology. The most critical issue was the reliability under high temperature operating conditions. With the corresponding simulations different assembly solutions and packaging materials are evaluated. These include ceramic technologies (low temperature cofired ceramic) in comparison to conventional coil designs. On the specific example the paper outlines the prospects and requirements of hardware design for microsystems by consistent application of simulation techniques.
... Non-contact displacement sensors are generally grouped in three categories: eddy current [1], capacitive and optical sensors. Eddy current proximity sensors [26], in particular ceramic ones, could be used in many industrial applications because their ability to work in harsh environments. Applications range from metallic target positioning, detection of holes, rivets or screws, pro®ling of metallic surfaces for automatic teller machines, to the precise measurement of automobile wheel position in ABS braking systems. ...
For certain applications low temperature co-fired ceramic (LTCC) tape materials used in multi-layer packages offers the potential of emulating a great deal of silicon sensor/actuator technology at the meso scale level. The goal of this review is to describe meso-system technology (MsST) using LTCC, thick film and silicon technologies.A mayor MST application being addressed today is fluid handling for miniaturized chemical analytical systems. For larger MST-3D applications, in the meso-size (from 10 to several hundred microns), it would be desirable to have a material compatible with hybrid micro-electronics, with suitable thermal, mechanical and electrical properties, easy to fabricate and inexpensive to process. Such a material is the LTCC tape multilayer system.One of the important features of LTCC technology is the possibility of fabricating 3D structures using multiple layers. In this review, we want to emphasize sensors and actuators for meso-systems exploring LTCC Tape possibilities in the following ways:•Sensors for proximity measurement;•Fluid media realization of vias, holes, cavities, channels and manifolds;•Sensors for flow measurement;•Actuators for hybrid microvalves & micropumps.
... Non-contact displacement sensors are generally grouped in three categories: eddy current [1], capacitive and optical sensors. Eddy current proximity sensors [26], in particular ceramic ones, could be used in many industrial applications because their ability to work in harsh environments. Applications range from metallic target positioning, detection of holes, rivets or screws, pro®ling of metallic surfaces for automatic teller machines, to the precise measurement of automobile wheel position in ABS braking systems. ...
For certain applications low temperature co-®red ceramic (LTCC) tape materials used in multi-layer packages offers the potential of emulating a great deal of silicon sensor/actuator technology at the meso scale level. The goal of this review is to describe meso-system technology (MsST) using LTCC, thick ®lm and silicon technologies. A mayor MST application being addressed today is ¯uid handling for miniaturized chemical analytical systems. For larger MST-3D applications, in the meso-size (from 10 to several hundred microns), it would be desirable to have a material compatible with hybrid micro-electronics, with suitable thermal, mechanical and electrical properties, easy to fabricate and inexpensive to process. Such a material is the LTCC tape multilayer system. One of the important features of LTCC technology is the possibility of fabricating 3D structures using multiple layers. In this review, we want to emphasize sensors and actuators for meso-systems exploring LTCC Tape possibilities in the following ways: Sensors for proximity measurement; Fluid media realization of vias, holes, cavities, channels and manifolds; Sensors for ¯ow measurement; Actuators for hybrid microvalves & micropumps. # 2001 Elsevier Science B.V. All rights reserved.
... Shell structures with curved geometry are useful for many reasons, since the curved geometry makes it very easy to mount a single sensor or an array of sensors on a macro-sized part. For example, if a flow meter made out of LTCC tapes (Gongora-Rubio et al 1999b) or a silicon sensor packaged using LTCC tapes needs to be mounted on a pipe, it is much more convenient and efficient to have a curved geometry. Since bonding LTCC surface to metals and many other materials is straightforward, direct mounting of the sensor on the surface is possible. ...
The objective of this research is to improve the quality of the KrF excimer laser micromachining of metal and silicon in fabricating electro-thermal-compliant (ETC) micro devices. The ETC devices combine the actuator and the mechanism into one monolithic compliant continuum and enable a range of mechanical manipulation tasks at micron scale. An efficient method for optimizing the process parameters in laser micromachining, using the orthogonal array-based experimental design method, is presented in this paper. The feed rate of the XY stage, the laser pulse frequency, the discharge voltage and the number of passes were used as the control parameters. The roughness of the machined edge was used as the primary indicator of cutting performance. The roughness of the edges was computed automatically from the optical image of the machined samples. The heat-affected zone, kerf width and rate of cutting depth (depth per one pass) were used as additional quality indicators. The orthogonal array method enabled the optimization of the control parameters by reducing the required number of experiments compared to the traditional full factorial experiment. Furthermore, machining in a liquid environment improved the quality and eliminated more debris and recast compared to machining in the air.
... Sensors and actuators with promising characteristics in aggressive environments have been developed using low temperature co-fired ceramic tape technology. Our group has developed gas flow sensors[4], eddy current proximity sensors[6] and other devices [5]. In the present paper we report our work on an electro-magnetically actuated normally closed valve [7]. ...
Sensors and actuators with promising characteristics in aggressive environments and high temperatures have been developed using low temperature co-fired ceramic tape technology. We would like to report our work on an electro-magnetically actuated normally closed valve. This is a hybrid device which utilizes a purely LTCC tape electro-magnet and fluid flow manifold, combined with an anisotropically etched silicon rectangular planar spring, and a high energy product SmCo mini-permanent magnet. Device dimensions are in the meso (intermediate) range with the smallest features (fluid conduit in the manifold) of 400 µm and the largest (the actuating coil) of 15 mm. All parts of the electromagnet and the fluid flow channels were machined from DuPont 951 series, alumina based LTCC tapes utilizing either a numerically controlled milling machine, a puncher or an isotropic etching technique involving the glassy binder of a partially sintered LTCC tape. Two versions of this device have been fabricated. The first one, a hybrid, and an all ceramic (LTCC) valve. The hybrid device, currently under evaluation, consists of five layers of planar spiral coils, connected as to preserve the magnetic field direction. The total coil resistance is high (120 Ohms) and thermal considerations limits the current to 150 mA. Using a 900 Gauss SmCo magnet (1mm diameter) we obtained 200 micrometers deflection of the rectangular planar spring with no hydraulic load. The best results so far are with the hybrid valve consisting of a silicon 30 micro-meter thick rectangular planar spring with a polysiloxane sealing element.
... The impedance versus distance curves are exhibited in Figs 4 and 5: Results agree well with simulation when the width of the curves and relative changes are regarded. [3] Two kinds of LTCC coils were designed for comparison. The materials of the substrate is made from the Dupont 951 green tape system and the conductor material is silver ink 6145 [4] . ...
Contact-less monitoring of the movement of blades is important in order to maintain the reliability of a turbine system. An eddy current sensor evidently is a good selection for such a device operating in the harsh environment of a turbo machine as it is insensitive to steam, dirt, oil etc. In our work, a flat eddy current sensor was developed utilizing the low temperature co-fired ceramics technology (LTCC). The focus of our work was the impedance investigation of a LTCC sensor coil in comparison to a conventional wire-wound sensor. In a first step, a design optimisation of the geometric structure was accomplished by means of a multi-physics FEM simulation. In that way also the sensitivity of the sensor was analysed. Based on the results of simulations, a LTCC sensor was designed and fabricated. The electromagnetic behaviour of the sensors was evaluated at different frequencies by simulation and experiment. Characteristic curves reflecting the relation of position and impedance were obtained. These results of this investigation contribute to the realisation of the LTCC sensor for measurements of horizontal movements.
