A Switchable Dual Band Antenna for Smart Devices in the UHF RFID- and the GPS L1 Band using MEMS

Inhalt:
The present publication describes the development of a dual band antenna for a small size RFID transponder with an integrated GPS Module for fawn saving during pasture mowing using MEMS. The localization of a conventional active UHF RFID transponder has obvious drawbacks in the needed hardware on the reader side. The transponder only sends its label and no further information regarding its position is available at the reader. Therefore, an additional direction finding system and a received signal strength (rss) detector for distance estimation in addition to the reader itself is needed. To prevent this complexity on reader side a transponder is developed with an integrated GPS Module for localization. Because of that, a switchable dual band antenna covering the 868 MHz UHF RFID- and the 1.575 GHz GPS L1 band is needed. To keep the transponder as small as possible two monopole chip antennas for the L1 band are in series connection with a MEMS Switch in between. With a closed gate at the MEMS the two monopoles act as one antenna for the UHF band. With a open gate only one antenna is used for the GPS L1 band.