Development of Embedded System to Measure Dielectric Properties of Conducting Polymers using Microcontrollers at Microwave Frequencies

This paper deals with the design and study of an embedded system for acquiring the dielectric constant, Dielectric loss, loss tangent at microwave frequencies using microcontroller controlled stepper motor. Dielectric properties of conducting polymers are measured manually by using microwave bench at X-band. These measurements are not precise when done manually. Hence, microcontroller based automatic measurement of the dielectric parameters is designed. Microcontroller based stepper motor move the probe of slotted section of X-band microwave bench. The positions of the probe are sensed by an optical section through 0.00650 mm and 0.00325 per step when the stepper motor is operated in full and half stepping mode respectively in forward or backward directions. This technique measures the width at the twice minima or maxima method obtained from the feedback signals of Standing Wave Ratio meter and is further used for the measurement of free space wavelength (λo) and waveguide wavelength (λg). This work also makes a comparative study of dielectrics properties of preferred conducting polymers such as PEDOT, PPDA, PPY, PTH and PANI.