A 915 MHz, Ultra-Low Power 2-Tone Transceiver With Enhanced Interference Resilience

An ultra-low-power RF envelope-detection radio has been designed for low-power short-range wireless applications. It introduces an interference rejection technique that improves the in-band selectivity by 24.5 dB. The transmitter adopts the power-efficient direct-modulation architecture, and the receiver maintains the simplicity and low power consumption of envelope detection receivers. In the 915 MHz ISM band at 10 kbps the transmitter output level reaches - 3 dBm with 33.9% global efficiency, while the receiver achieves -83 dBm sensitivity with 121 μW power consumption. The Tx and Rx implemented in 90 nm CMOS technology occupy 0.71 and 1.27 mm² , respectively.

I. Introduction

Advances in wireless transceiver design have enabled a broad range of new short-range, low-power applications, such as the wireless sensor (WSN) [1], wireless body-area (WBAN) [2] and wireless personal-area networks (WPAN) [3]. In these applications, wireless-nodes are typically deployed with limited energy sources, whereas long operation lifetime is desired. Therefore, power consumption of the radio nodes must be minimized. The average power consumption of each node must be limited to 100 W in order to operate autonomously with only the help of energy harvesters [4]. The radio transceivers often consume the majority of the available energy. The transmitter (Tx) is normally duty-cycled, so that the peak power consumption can be several times higher than the average power budget. On the other hand, applications such as healthcare monitoring and asynchronous wake-up radios [5], [6], may demand the receivers (Rx) to operate continuously. To address these stringent requirements, this work targets the design of a low power radio transceiver with an asymmetric power budget; 100 W for the receiver to enable continuous operation, and 1 mW for the transmitter to enable duty-cycle up to 10%.