Energy Autonomous Two-Way Repeater System for Non-Line-of-Sight Interrogation in Next Generation Wireless Sensor Networks

In this effort, we present a fully energy autonomous two-way repeater system for use in nonline-of-sight (NLOS) interrogation of wireless sensor networks. The proposed system is based on a pair of tunnel diode reflection amplifiers, taking advantage of the existence of a negative differential resistance region that exists when the device is biased at a low voltage in the quantum tunneling region. This enables the development of an ultralow-cost, ultralow-power means to provide amplification. The proposed system demonstrates an ability to extend the total read range of semipassive radio frequency identification (RFID) tags by 4.55 times while consuming over 1000 times less power than comparable technologies, a notable improvement on previously published work. The system shows an ability to be customized to fit a wide array of different applications where NLOS interrogation and the read range of semipassive RFID tags pose a challenge.