A 5-GHz 0.15-mm² Collision-Avoiding RFID Employing Complementary Pass-Transistor Adiabatic Logic With an Inductively Connected External Antenna in 0.18-μm CMOS

Abstract

A low-power, small form factor, and collision avoiding RFID tag is proposed. By applying complementary passtransistor adiabatic logic (CPAL) and two-phase clock, not only the required power of operation is lowered, but also large capacitors necessary for stable operation are eliminated, which leads to a reduced chip size. Additionally, the external antenna used is inductively connected instead of solder-bonded, which contributes to a lower assembly cost. A collision avoidance system exploiting counter and bit shift is also proposed. Results show the proposed RFID is capable of communication twice as far as the one using conventional adiabatic logic with one-eighth of the reader’s transmission power, as well as having the whole chip downsized by 94%. It is also confirmed that collisions between three tags are avoided thanks to the collision avoidance system.