Difference between revisions of "Differential RCS"
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Differential RCS characterizes the aptitude of a tag to modulate the backscattered power. This parameter is has been introduced by P. Nikitin | Differential RCS characterizes the aptitude of a tag to modulate the backscattered power. This parameter is has been introduced by P. Nikitin for UHF tags <ref>P. V. Nikitin, K. V. S. Rao, and R. D. Martinez, “Differential RCS of RFID tag,” Electronics Letters, vol. 43, no. 8, pp. 431–432, Apr. 2007.</ref> and is classically estimated based on the variation of the IQ channels of the two states of the chip in the time domain. This quantity can however be generalized for any modulating tag in the frequency domain. The frequency definition remains (almost) compatible to the time definition. Finally, this new definition allows to estimate the delta RCS of any tag accurately using a simple spectrum analyzer. | ||
[[File:Delta.png|thumb|right|PSD backscattered by a modulating tag in the frequency domain.]] | [[File:Delta.png|thumb|right|PSD backscattered by a modulating tag in the frequency domain.]] | ||
Revision as of 09:44, 8 July 2021
Differential RCS characterizes the aptitude of a tag to modulate the backscattered power. This parameter is has been introduced by P. Nikitin for UHF tags [1] and is classically estimated based on the variation of the IQ channels of the two states of the chip in the time domain. This quantity can however be generalized for any modulating tag in the frequency domain. The frequency definition remains (almost) compatible to the time definition. Finally, this new definition allows to estimate the delta RCS of any tag accurately using a simple spectrum analyzer.
Details have been presented in [2] and can be seen as a complementary definition compared to the time definition. The basic idea relies on the decomposition of the RCS into a static RCS and a dynamical RCS and to pass into the frequency domain. Fig. 1 presents the main result where the (total) backscattered signal by the modulating UHF tag can be decomposed into 2 parts. Component located at Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://en.wikipedia.org/api/rest_v1/":): {\displaystyle f_0} can be linked to Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://en.wikipedia.org/api/rest_v1/":): {\displaystyle \sigma_s} whereas component located around Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://en.wikipedia.org/api/rest_v1/":): {\displaystyle f_0} can be linked to .
Also, this frequency definition (as the original definition) is not limited to RFID tags and can be applied to any linear time-varying system such as rotating tags, moving tag and (surprisingly) barcodes.
- ↑ P. V. Nikitin, K. V. S. Rao, and R. D. Martinez, “Differential RCS of RFID tag,” Electronics Letters, vol. 43, no. 8, pp. 431–432, Apr. 2007.
- ↑ N. Barbot, O. Rance, and E. Perret, "Differential RCS of modulated tag," IEEE Transactions on Antennas and Propagation, pp. 1–1, 2021, early access. doi: 10.1109/TAP.2021.3060943.