A MEMS-based 2.4-GHz sub-sampling RF front-end for advanced healthcare applications

This work presents a Bulk Acoustic Wave (BAW) resonator based 2.4-GHz front-end compliant to the Bluetooth LE standard and targeting advanced biomedical applications. A new transceiver architecture is proposed that combines BAW resonators and a sub-sampling architecture. It takes advantage of the high-Q of BAW resonators to perform channel filtering directly at RF. At the same time it also carries-out the critical anti-alias filtering required by the subsequent sub-sampling down-conversion mixer generating quadrature samples of the selected channel at baseband. The high-Q resonator is also used in the frequency synthesis to provide a low phase noise reference clock. The front-end has been designed and integrated in a 0.18-μm standard CMOS process and the principle is validated with simulations and measurement results.