A Microstrip Antenna with a Reconfig- Urable Pattern for Rfid Applications

This paper presents a low-cost patternreconfigurable microstrip antenna. The proposed design strategy uses a slotted patch antenna on a bi-layer structure as basic element of a switched parasitic array. Reconfigurability is obtained by means of PIN diodes used to vary the resonance frequency of the parasitic patches. Experimental results referring to a prototype consisting of an array of three elements optimized for the Ultra High Frequency (UHF) band of Radio Frequency IDentification (RFID) systems are presented and discussed. It is demonstrated that the proposed antenna exhibits a main beam that can be reconfigured into three different directions.