Harmonic Voltage Reflection Analysis of UHF RFID Chips

In recent years, the exploitation of the nonlinear behavior of ultrahigh-frequency (UHF) radio frequency identification (RFID) chips has gained popularity. This article presents a measurement platform for the harmonic characterization of UHF RFID chips. The measurement of the incident and reflected wave at the RFID chip terminals is performed using a digital sampling oscilloscope (DSO). A novel signal-processing methodology is presented to extract time-domain reflection coefficient equivalents from a DSO measurement at the different load modulation states. Using a simultaneous measurement of the reflection coefficient with a vector network analyzer, the obtained measurement results were validated. Furthermore, a comparison to using real-time sampling and a power spectral density analysis is presented.