Data Transfer in an Injection-Locked Oscillator Coupled to an External Resonator

This work proposes the use of an injection-locked oscillator inductively coupled to an external resonator for power and data transfer. The injection locking prevents the variation of the oscillator carrier frequency with the coupling factor, while taking advantage of the oscillation to obtain high output power and efficiency under a low input amplitude. By using a rectifier, the inductively coupled oscillator can power a low-frequency source in the external resonator, which is used to modulate the oscillator signal. The high phase sensitivity of the locked regime enables a phase modulation through the variation of the external-resonator capacitance. This way data can be transmitted from the resonator to the oscillator, acting as a reader. A proof of concept has been implemented using a Class-E oscillator operating at 13.56 MHz, with good experimental results.