| Popis: |
A novel antenna system for short-range wireless communications with implantedbiomedical devices is proposed. Wireless signals are received through theelectromagnetic near-field using a group of antennas rather than one. Signals from eachantenna are phase aligned and summed to boost the overall received signal. Thereceiving array consists of two antennas, spanning a rectangular area of 10 cm by 18 cm.A phase shifting circuit, capable of altering signal phase by 251°, was designed for use inphase alignment. A phase detection and control circuit was designed to assess thedifference in phase between received signals, and to generate a control signal for thephase shifting circuit, in order to dynamically align phases. The loop bandwidth of thecontrol system is approximately 10 Hz. Each receiving channel of the system has a noisespectral density of 0.41 nV/RT Hz. |
