Low-Power 2.4-GHz Transceiver With Passive RX Front-End and 400-mV Supply

A 4-Element Phased-Array System With Simultaneous Spatial- and Frequency-Domain Filtering at the Antenna Inputs

“…This spatial filtering is up-converted to the RF node via passive mixers, so that it occurs directly at the antenna inputs. Moreover RC low-pass filtering also occurs on the capacitors, which is also up-converted, rendering high-Q N-path frequency-domain filtering at RF [12][13][14][15][16][17][18][19][20].…”

“…3, N-path RC frequency-domain filtering also occurs on the baseband capacitors, which is up-converted to the switching frequency and its harmonics [14,16,18,21]. The periodically time-variant nature of N-path filters introduces frequency shifts by multiples of the clock frequency.…”

Wake-up Receiver Based Ultra-Low-Power WBAN

“…Other low-power receivers use FSK modulation [9,[12][13][14][15], which is slightly more interferer-robust than OOK modulation [27]. Because the frequency reference needs to be stable, most FSK receivers use power consuming PLLs [9].…”

“…The power consumption of the presented oscillator including LO buffers is only 77µW at 900MHz, which is much lower than the oscillators presented in literature. However, the linearity and noise figure of [9,13,18] are better, showing a trade-off between power consumption and linearity. Especially [9] has a much higher linearity at the cost of a high power consumption, which makes the receiver better suited for high performance applications.…”

“…Compared to the reported FSK receivers, the WURxV2.1 has a low power consumption, especially taken into account that [12,13,16] do not have frequency calibration or an on-chip demodulator. Direct comparison in power consumption is difficult since also other parameters are different.…”