A Highly Reconfigurable Bit-Level Duty-Cycled TRF Receiver Achieving −106-dBm Sensitivity and 33-nW Average Power Consumption

Low-Power RF Wake-Up Receivers: Analysis, Tradeoffs, and Design

“…Sensitivities down to -86 dBm have been achieved with 10s of µW [14]- [16]. To further reduce the power consumption at the cost of increased latency, bit-level duty-cycling can be employed, with -106 dBm sensitivity demonstrated with only 33 nW using an off-chip high-Q MEMS filter [17]. Section III describes these designs and their relevant trade-offs in more detail.…”

“…Such amplifiers approach stability boundaries to maximize the power gain of the device for a given bias current. Most regenerative amplifiers are based on oscillator structures such as Colpitts [48] or ring oscillators [17], which are backed off somewhat from the unstable region where the loop gain approaches unity, allowing for considerable gain at low DC power. However, such amplifiers require careful biasing to guarantee stable operation across process, voltage, and temperature variation.…”

A 5.5–7.5‐GHz band‐configurable wake‐up receiver fully integrated in 45‐nm RF‐SOI CMOS

“…Since the Q-factor decreases significantly as the carrier frequency increases, these WuRXs are further constrained to applications with frequencies below 1 GHz. 400 − 500-MHz is a particular frequency range that attracts most of the state-of-the-art WuRXs from this class to locate in, for instance [10,12,13,[16][17][18][19]. Furthermore, due to insufficient gain at the RF path, they may easily suffer from lower signal-to-noise ratio (SNR) at the BB and hence obtain a worse sensitivity compared to FC WuRXs.…”

“…Moreover, since such high-Q passive components are only available at lower frequencies ≤2. 4 GHz, state-of-the-art WuRXs have been designed also in these frequencies, for instance, 400 − 500-MHz WuRXs from [10,12,13,[16][17][18][19] and 2.4-GHz WuRXs from [6,[20][21][22][23][24]. Nevertheless, the antenna size for such low-frequency WuRXs or related transceivers has to be large to maintain sufficient gain, thus limiting the system integration.…”

“…4 GHz, the related RF channels haven been confronted with saturated traffic conditions leading to in-band data collision, out-of-band interference, hence higher false alarm rate of the WuRXs and prolonged communication latency. This issue could be addressed on the level of medium access protocols (MAC), for instance, WuRX-based MAC protocols proposed in [25,26], and/or by designing WuRXs with higher robustness against interference such as [16,17,[20][21][22]. However, all these approaches increase the system complexity and cost and do not substantially resolve the channel saturation issue.…”