Analysis of phase sampling noise of switched injection-locked oscillators

In this paper, a fully integrated active backscatter transponder based on the switched injection-locked oscillator (SILO) principle for frequency modulated continuous wave (FMCW) radar applications is presented. Furthermore, a novel theory to model the phase sampling behaviour of a SILO, accounting for noisy injection signals, is derived. The presented backscatter tag operates at 34.5 GHz and reaches a steady-state output power of 7 dBm. The input referred noise power of the SILO is −66 dBm. In system measurements, a remarkably good accuracy of 5 cm and a precision better than 2 mm was achieved in an indoor environment at ranges from 0.7 m to 17 m. In outdoor measurements an accuracy of 2 cm and a precision 1 cm was achieved for ranges from 45 m to 103 m.