High sensitive RF-DC rectifier and ultra low power DC sensing circuit for waking up wireless system

A 2.4 GHz band high-efficiency RF rectifier and high sensitive DC voltage sensing circuit is implemented. A passive RF to DC rectifier of multiplier voltage type has no current consumption. This rectifier is using native threshold voltage diode-connected NMOS transistors to avoid the power loss due to the threshold voltage. It consumes only 900 nA with 1.5 V supply voltage adopting ultra low power DC sensing circuit using subthreshold current reference. These block incorporates a digital demodulation logic blocks. It can recognize OOK digital information and existence of RF input signal above sensitivity level or not. A low power RF rectifier and DC sensing circuit was fabricated in 0.18 ¿m CMOS technology with native threshold voltage NMOS. This RF wake up receiver has -28 dBm sensitivity at 2.4 GHz band.