Model-based VF technique for parasitic reflections reduction of frequency-domain chipless RFID systems

In a frequency-domain chipless RFID system, the backscattered signal from a tag is directly obtained in the frequency domain over limited bandwidth. However, to reduce the parasitic reflections, it is crucial to obtain the backscattered signal in the time domain. This letter proposes a precise quasi-analytic method, known as the model-based vector fitting (VF) technique, to provide the closed-form equation of the backscattered response in the time domain. The proposed method successfully recovers a tag's identification (ID) among parasitic reflections using a single tag measurement without requiring prior knowledge about the tag.