A reference modulated scatterer for ISO18000-6 UHF tag testing

We present a method for measuring ultra-high frequency radio-frequency identification (UHF RFID) tag differential RCS that has the potential for being easier and more accurate than current and proposed methods [1-2]. Our method is based on accurately characterizing the reflection states of a modulated load, accounting for transmission losses between the load and an antenna, and using a well-known, low gain antenna. This has the benefit of using a well characterized “golden tag” reference (i.e., repeatability), while being more linear in power response, independent of reader signal, and independent of manufacturer or process changes. Characterizations of the losses in the reference scatterer allow for direct comparisons between tags on different test beds.