A miniaturized low-profile two-bit QPSK metamaterial inspired phase modulated chipless RFID tag
RFID is a non-contact automatic identification technology, which automatically identifies target objects and obtains relevant data by radio frequency (RF) signals without manual intervention. However, the high cost and difficulty to fabricate comparing with barcodes limits RFID tags to replace b...
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| Format: | Thesis |
| Language: | English |
| Published: |
2018
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| Online Access: | http://hdl.handle.net/10356/75988 |
| Summary: | RFID is a non-contact automatic identification technology, which
automatically identifies target objects and obtains relevant data by radio
frequency (RF) signals without manual intervention. However, the high cost and
difficulty to fabricate comparing with barcodes limits RFID tags to replace
barcodes. Chipless RFID tags refer to RFID tags that do not contain silicon chips
which mainly have advantages of low cost and ease to fabricate.
In this thesis a vialess passive two-bit metamaterial based Quadrature Phase
Shift Keying (QPSK） modulated Chipless RFID tag operating at 2.4 GHz is
presented. Based on QPSK modulation, there are four different phase changes of
the tag backscattered signal over a period of time. These four phase changes
correspond four QPSK symbols by using four independent phase modulating
sections which have unique reflection coefficients. The compact CRLH based
vialess antenna is an open end zeroth order resonating antenna which is an open
end CRLH transmission line(TL) structure with a 0.286λ0*0.168λ0*0.0065λ0 size
at 2.4GHz. The time delay of vialess structure is realized by CRLH delay lines
which proved to be very useful in reducing the overall size of the circuit while
offering significantly longer delays at lower frequencies [1] comparing with
conventional right hand true time delay lines. The composed CRLH delay line
provides a 3ns time delay. SRRs and CSRRS are used as discontinuities to
achieve abrupt phase changes of backscattered signals. The dimensions of the
Chipless tag is 0.32λ0*0.546λ0*0.0065λ0. This Chipless RFID can be used by
connected with temperature sensor as well [40] .
Measurement and simulation results show that the proposed Chipless RFID
tag is compact and delivers the desired performance. |
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