Analysis of UHF-band Passive RFID Antennas Loaded by Dickson Charge Pump

摘要

This paper presents the shape optimization of the meander line antennas (MLA) loaded by integrated circuit for UHF-band passive radio frequency identification (RFID) tag. In this RFID system, the reader communicates with searval RFID tags composed of an antenna and IC chip by the electromagnetic waves. To realize long range communication between the reader and RFID tag, it is necessary to provide impedance matching between the antenna and IC chip. Hence the characteristics of RFID tags composed of MLA and Dickson charge pump (DCP) circuit are analyzed by hybridization of the finite-difference time-domain method and modified nodal analysis. The shape of MLA is optimized by the micro genetic algorithm so that the output voltage of DCP circuit is maximized. The non-linearity of V-I characteristics of FET included in DCP circuit is approximated by the Akima incorpolation. It is shown that the output voltage of DCP circuit can effectively be increased by the present method.