3 research outputs found

    Multi-channel ultra-low-power receiver architecture for body area networks

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    Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 85-91).In recently published integrated medical monitoring systems, a common thread is the high power consumption of the radio compared to the other system components. This observation is indicative of a natural place to attempt a reduction in system power. Narrowband receivers in-particular can enjoy significant power reduction by employing high-Q bulk acoustic resonators as channel select filters directly at RF, allowing down-stream analog processing to be simplified, resulting in better energy efficiency. But for communications in the ISM bands, it is important to employ multiple frequency channels to permit frequency-division-multiplexing and provide frequency diversity in the face of narrowband interferers. The high-Q nature of the resonators means that frequency tuning to other channels in the same band is nearly impossible; hence, a new architecture is required to address this challenge. A multi-channel ultra-low power OOK receiver for Body Area Networks (BANs) has been designed and tested. The receiver multiplexes three Film Bulk Acoustic Resonators (FBARs) to provide three channels of frequency discrimination, while at the same time offering competitive sensitivity and superior energy efficiency in this class of BAN receivers. The high-Q parallel resonance of each resonator determines the passband. The resonator's Q is on the order of 1000 and its center frequency is approximately 2.5 GHz, resulting in a -3 dB bandwidth of roughly 2.5 MHz with a very steep rolloff. Channels are selected by enabling the corresponding LNA and mixer pathway with switches, but a key benefit of this architecture is that the switches are not in series with the resonator and do not de-Q the resonance. The measured 1E-3 sensitivity is -64 dBm at 1 Mbps for an energy efficiency of 180 pJ/bit. The resonators are packaged beside the CMOS using wirebonds for the prototype.by Phillip Michel Nadeau.S.M

    A 2.4 GHz 3.6mW 0.35mm2 quadrature front-end RX for ZigBee and WPAN Applications

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    In the design of a single chip for wireless-sensor-network and WPAN applications (e.g., IEEE 802.15.4), the receiver sensitivity is generally sacrificed in favor of a vanishing power consumption and a low-cost solution. There is a trade off between these two requirements, as the use of resonant loads offers high power efficiency while an inductor-free approach saves die area resulting in a cheaper design. Since an LC-oscillator topology is mandatory to achieve a minimal current draw, the reduction of the number of coils has to be done in the LNA, the mixer and the quadrature generator. In this work, starting from the LNA-Mixer and VCO (LMV) cell topology, a single-coil low-power receiver shares the bias current among all the RF blocks of the analog front-end. The receiver prototype chip consumes 3.6mW and has an active die area of 0.35mm2. It is based on a low-IF architecture and includes a baseband variable-gain complex filter for channel selection
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