Abstract :
Highly directional aerial systems have been used to exclude signals arriving via spurious paths in communication systems, in order to reduce intersymbol distortion or frequencyselective fading. It is then necessary to use a tracking facility if one of the terminals is moving with respect to the other. In this letter, the problems associated with self-tracking aerials or acoustic transducers in multipath-propagation conditions are considered, and some proposals are made for the realisation of such arrays.