Millimeter Wave Dual-Polarized Semi-Passive Energy Detection Backscattering RFID

This paper presents a dual-polarized semi-passive energy detection backscattering RFID at 28 GHz. A 2 by 2 dual-polarized patch antenna array, a Wilkinson power combiner, a low noise FET switch, and a half-wave self-biased rectifier made of a MA4E2037 Schottky diode are designed and optimized on Rogers RO4350B substrate. The antenna is dual-polarized to separate energy harvesting/detection and backscattering features of the system. By adding the biasing load, the rectifier has a low turn-on input power level and can output 0.3 V at an input power of −5 dBm. It reaches the highest power conversion efficiency of 40.2 % with an input power of 12.2 dBm. The rectifier provides a low voltage into a low-power op-amp that connects to an oscillator feeding into a low-noise FET switch for backscattering signal modulation at 270 kHz. This RFID tag can operate up to 40 m with 75 dBm EIRP.