Evolutionary design of miniaturized meander-line antennas for RFID applications

Radio frequency identification (RFID) of objects or people has become very popular in many service industries, distribution logistics, manufacturing companies and goods flow systems. In these applications data are contactless transferred to a local querying system (reader) from a remote transponder (tag) including an antenna and a microchip transmitter. In this paper we discuss versions of the standard meander line antenna (MLA) which are obtained by a proper shaping of the conductor in order to best utilize the wire current and improve the antenna gain while keeping the size small. To explore efficiently a large number of MLA configurations, an evolutionary approach has been considered. It is based on a genetic algorithm optimization (GA) and the method of moments (MoM) to design the best length for each meander line segment. Example are presented for a MLA tag tuned at 869 MHz (one of the European RFID frequencies) with size smaller than (4 /spl times/ 3.5 cm/sup 2/).