Millimeter-wave phase-modulated backscatter transponder for FMCW radar applications

A millimeter-wave phase-modulated backscatter transponder in the E-band for readout with a frequency-modulated continuous-wave (FMCW) system is presented in this paper. Backscatter transponders have the advantage that, while no complete radio-frequency front end hardware, including signal generation, is required, they offer the capability to establish a one-way communication between the transponder and an interrogator. As we used an FMCW radar system as an interrogator, it is possible to extract range information as well as the modulated information from the transponder. In this paper we present the system basics as well as a fabricated prototype from which we obtained measurement results.