Designing Fractional Oscillator for Sensing Different Types of Lossy Capacitors

In this work, a new type of fractional oscillator circuit is proposed employing two fractional capacitors. Based on the Barkhausen criteria, a generalized closed-form equation for the oscillating frequency has been derived with simple design equations. The closed-form design equation enables the circuit to be used as a signal conditioning circuit for any type of lossy capacitive sensor. Experimental results of the fractional oscillator as a signal generator as well as a signal conditioning circuit are presented. Performance as a signal conditioning circuit is studied by using an emulated lossy capacitor and a stick-type lossy capacitive type sensor.