A multi-antenna signaling scheme, system and method for passive or low-powered RF devices, such as a radio frequency identification tag, are herein described. In one embodiment, the presently disclosed subject matter discloses a Retrodirective Array Phase Modulator which is configured to allow RFID tags to return higher-powered signals with higher data rates back to an RFID interrogator or reader unit. In some configurations, pattern strobing is used which is an array-based transmission technique for stepping or sweeping an RF waveform through space so that passive radio devices may more efficiently harvest energy without increasing transmit power. In some configurations, the presently disclosed subject matter may also use a Staggered Pattern Charge Collector to boost the collection of microwave power.