Koji Dairiki

RFCPUs on glass and plastic substrates fabricated by TFT transfer technology

On the basis of the fabrication of a CPU on glass as a digital circuit presented in B. Lee et al. (2003) and T. Ikeda et al. (2004), as well as the fabrication of a flexible CPU using a TFT transfer technology presented in T. Takayama et al. (2004), we have succeeded in the development of the worlds first flexible RFCPUs (8bit, passive type) by adding to the CPU an antenna, an analog circuit, an encryption function and an RFID function, which operate using an RF signal with a frequency of 13.56MHz

UHF RFCPUs on Flexible and Glass Substrates for Secure RFID Systems

A radio frequency integrated circuit (RFIC) tag consisting of an 8 bit CPU, a 4 kB ROM, a 512B SRAM, and an RF circuit, which communicates using 915 MHz UHF RF signals, has been developed on both a flexible substrate and a glass substrate. Each of the RFIC tags employs a single DES and an anti-side channel attack routine in firmware for secured communication, and occupies an area of 10.5 mm in width and 8.9 mm in height. The RFIC tag on the flexible substrate is 145 mum thick and weighs 262 mg, and the RFIC tag on the glass substrate consumes 0.54 mW at a power supply voltage of 1.5 V and communicates with a maximum range of 43 cm at a power of 30 dBm. The high-performance poly-silicon TFT technology on flexible substrate and glass substrate of 0.8 mum design rule, and a gate plus one metal layer are used for fabrication. The RFIC tag realizes stable internal clock generation and distribution by a digital control clock generator and a two-phase nonoverlap clock scheme, respectively.