Design of a switched injection-locked oscillator at 2.45 GHz for a local positioning system

In this paper, a fully integrated active reflector transponder for the localization and quick evacuation of passengers in the sea in case that passengers are overboard is presented. The backscatter tag is based on a cross-coupled oscillator topology using the switched injection-locked oscillator (SILO) principle and is implemented in a frequency modulated continuous wave (FMCW) radar. Furthermore, a novel theory for calculating the input referred noise power of a SILO is applied. The presented backscatter tag operates at 2.45 GHz and reaches a steady-state output power of 7.5 dBm. The measured input referred noise power of the SILO reaches a remarkable value of -80 dBm.