915MHz ultra low power receiver using sub-Vt active rectifiers

A 98nW receiver with a 23nW active rectifier RF front-end biased in deep subthreshold near the saturation/linear boundary is presented. An on-chip voltage reference and 28nW hysteretic comparator are also designed using subthreshold techniques. The receiver can demodulate an OOK signal at 100kbps with a sensitivity of -41dBm and all processing for process and mismatch is handled on-chip [1]. The ultra-low power receiver is used for wireless sensor node applications, specifically for nodes that are to be worn on the body.