Antenna array for the reader of an ultra-wideband identification tag with on-chip antenna

We have designed and implemented an ultra-wideband radio frequency identification tag (UWB RFID). We discuss its design and the corresponding reader which employs an antenna array. The manufactured UWB RFID prototype with a size of 1 × 1.3 mm² features an on-chip antenna (OCA) and transmits UWB pulses which are modulated by on-off keying (OOK). Utilization of an antenna array at the reader yields array gain and offers the capability to localize the UWB RFID. Finally, we propose a method for estimating pulse repetition interval based on the measured power spectral density of the received signal at the reader side.