93929 - Sensors and Nanotechnology

Learning outcomes

At the end of the course, the student acquires basic knowledge for understanding and using transducers and the related electronic interfaces. In particular, the student learns to approach the topic from a systemic point of view, emphasizing the common elements of the different types of sensors, regarding their evaluation and characterization. The didactical means are focused on continuous technological development to satisfy the growing design needs in biomedical engineering. Knowledge will also be aimed at learning about modern manufacturing techniques in nanotechnology and laboratory techniques helpful in analyzing nanometric structures, which are of growing importance in biomedical laboratories. In addition, the student will know how to orient himself to the advanced applications of sensors in environmental monitoring and energy saving.

Course contents

• Introduzion of the course, example of research

• Sensors as a black-box. Concept of sensitivity, and relative sensitivity at first order approximation.

• Measurements, precision, accuracy and resolution. Full scale and dynamic range.

• Recall of stocastic signals. Rms values and mean square values, standard deviations. Power spectral density. Correlation, autocorrelation and cross-correlation.

• Suprimposition of noise powers in uncorrelated signals.

• The origin of noise. Brownian noise. The example of pressure sensor.

• Noise in electronic components. Thermal noise and its derivation.

• Possonian processes. Shot noise and related derivation.

• Concept of input-referred noise. Input referred noise in BJT and MOS devices.

• The flicker noise and its derivation. Physical origin of flicker noise.

• Equivalent noise bandwidth. Signal-to-noise-ratio (SNR)

• White and pink noises.

• Acquisition sensor chain. Probability errors and equivalent number of levels.

• Noise in OPAMPs

• Resistive sensors interfaces. Wheatstone bridge and its sensitivity.

• Microcontroller sensing of resistors and capacitances. Ratioed measurements.

• Strain-gauges. RTDs e PRTs.

• Thermistors, NTC e PTC. Magnetic sensors.

• Capacitive sensors. Capacitance matrix. Kelvin guard ring.

• Charge amplifier. Differential capacitive sensing. Capacitive accelerometers.

• Noise in charge amplifiers. Correlated double sampling (CDS).

• Open and closed loop sensing. Oversampling converters. Sigma-Delta converters. Decimators.

• Lock-in e chopper sensing. Complex impedance measurements by lock-in sensing.

• Introduction to optical sensors. The photodiode. Charge and voltage photodiode readout in storage mode.

• Sensor networks.

• Array of optical sensors. Passive pixel CMOS sensors (PPS) and active pixel (APS) sensors. APS with correlated doble sampling. CCD principles.

• Teoria del colore and color filtering.

 

Office hours

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