Cavity-Backed Double H-Slot Antenna With IPMC Flaps for Designing Frequency-Switchable On/In-Metal Semi-Active Tag

A frequency-switchable semiactive tag antenna that can perform well on both the on- and in-metal platforms is proposed. A double H-slot antenna has been employed for designing the tag, and it can be easily made using a copper-clad polyimide film. The proposed antenna structure has a backing metallic cavity, which has made the read performance very robust even being used for the in-metal platform. To achieve the frequency reconfiguration, the ionic polymer–metal composite (IPMC) actuators are coated with metal, and they are tactfully integrated with a double H-slot antenna for changing its shape. The IPMC flaps can be actuated with a low operating voltage for switching the tag antenna across the U.S. and EU radio frequency identification (RFID) passbands. A water-embedded substrate that consists of a polydimethylsiloxane (PDMS) container filled up with water has also been employed for miniaturizing the antenna. Good maximum read ranges (> 10 m) have been achieved for all cases.