Julien Ryckaert

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Using ultra-wideband (UWB) wireless sensors placed on a person to continuously monitor health information is a promising new application. However, there are currently no detailed models describing the UWB radio channel around the human body making it difficult to design a suitable communication system. To address this problem, we have measured radio(More)
The successful realization of a wireless body area network (WBAN) requires innovative solutions to meet the energy consumption budget of the autonomous sensor nodes. The radio interface is a major challenge, since its power consumption must be reduced below 100 /spl mu/W (energy scavenging limit). The emerging ultra-wide-band (UWB) technology shows strong(More)
Using wireless sensors placed on a person to continuously monitor health information is a promising new application. In developing these sensors, detailed knowledge of the communication channel is essential. However, there are currently very few measurements describing propagation around the body. To address this problem, we have measured electromagnetic(More)
A digital UWB TX that supports the IEEE 802.15.4a standard is presented. A digitally controlled oscillator produces the RF carrier for all bands between 3 and 10GHz. It is embedded in a phase-aligned frequency-locked loop that starts up in 2ns and thus exploits the signal duty-cycle that can be as low as 3%. A digital modulator shapes the BPSK symbols at(More)
Using wireless sensors placed on a person to continuously monitor health information is a promising new application. However, there are currently no models describing the radio channel around the human body making it difficult to design a suitable communication system. To address this problem, we have simulated electromagnetic wave propagation around the(More)
A sixth-order RF bandpass DeltaSigma ADC operating on the 2.4 GHz ISM band, which is suitable for RF digitization is presented. The bandpass loop filter is based on digitally programmable Gm-LC resonators that can be calibrated online to adjust the RF center frequency. By sampling below the input Nyquist frequency, the clock in the system was reduced to 3(More)
The successful realization of a Wireless Body Area Network (WBAN) requires innovative solutions to meet the energy consumption budget of the autonomous sensor nodes. The radio interface is a major challenge, since its power consumption must be reduced below 100μW (energy scavenging limit). The emerging Ultra-WideBand (UWB) technology shows strong advantages(More)
This paper gives an overview of results of the Human++ research program. This research aims to achieve highly miniaturized and autonomous transducer systems that assist our health and comfort. It combines expertise in wireless ultra-low power communications, 3D integration technologies, MEMS energy scavenging techniques and low-power design techniques
A low-power impulse-radio ultra-wideband receiver is demonstrated for low data-rate applications. A topology selection study demonstrates that the quadrature analog correlation is a good receiver architecture choice when energy consumption must be minimized. The receiver operates in the 3.1-5 GHz band of the UWB FCC spectrum mask on channels of 500 MHz(More)
This paper shows that multirate processing in a cascaded discrete-time modulator allows to reduce the power consumption by up to 35%. Multirate processing is possible in a discrete-time modulator by its adaptibility with the sampling frequency. The power reduction can be achieved by relaxing the sampling speed of the first stage and increasing it(More)