A 500°C tolerant ultra-high temperature 2.4 GHz 32 bit chipless RFID tag with a mechanical BPSK modulator

Abstract

We present an ultra-high temperature 2.4 GHz chipless RFID tag capable of operation at temperatures of over 500°C. This tag uses a novel mechanical BPSK backscatter modulator driven by a high speed rotating shaft to telemeter a 32 bit unique ID as a BPSK symbol sequence at a rate synchronous to the rotation of the shaft. The tag integrates a 9 dBi linearly polarized air-dielectric patch antenna. It is a proof of concept for applications in remotely identifying components and measuring rotation rates in high speed, high temperature equipment such as jet engines, industrial turbines, and down-hole oil drilling equipment. To ensure high reliability, there are no switch contacts in this design. Unlike traditional CMOS IC based RFID tags, this tag has no RF power-up threshold and can be interrogated at an extremely low incident power. Unlike SAW and multiple resonator based chipless tags, an unmodulated 2.4 GHz CW excitation is sufficient to read out the digital bit stream from the tag. In laboratory testing, a read range of over 2 m is achieved with an interrogator power of only +5 dBm. At a rotation rate of 206.8 RPM, the tag telemeters data at 110.3 symbols per second. The approach can easily be extended beyond 32 bit IDs.