An antenna concept for an optically powered SHF RFID transponder applicable into metal

This paper presents a hybrid antenna design for an optically powered super high frequency (SHF) RFID transponder applicable for the integration into metal. The key feature of the antenna is its ability to receive microwave signals at SHF for the data communication and optical signals for the power supply of the transponder. The antenna design is based on a circular waveguide which is filled with polymer optical fibers to guide light to the photodiodes to power up the transponder. Additionally a transition is placed within the circular waveguide to transfer the waveguide mode of the SHF signal into a microstrip mode which is a more suitable structure for the integration of electronic transponder components. This paper discusses the constraints and solutions for the here presented combination of SHF microwave and light. Furthermore, the gain of the antenna structure is measured and compared to the simulated one.