13.56MHz CMOS-Based Crystal Oscillator for Wireless Power Transfer Application

This paper deals with the development of CMOS-based crystal oscillator works on the frequency of 13.56MHz for wireless power transfer (WPT) application. The use of a 13.56MHz crystal and a 74HC04N CMOS integrated circuit (IC) as main parts of oscillator is aimed to have a stable sine wave generator in compact configuration. In order to have good impedance matching, a common collector BJT amplifier is applied as an impedance matching circuit. The oscillator as well as the impedance matching circuit are deployed on a single layer of FR4 epoxy dielectric substrate with the thickness of 1.6mm. The characterization result demonstrates that the proposed oscillator could generate a stable sine wave at the frequency of 13.56MHz with the output signal level of -4.79dBm, in which this is suitable for WPT application.