  The arterial pulse wave, which propagates along the artery, is an important
indicator of various cardiovascular diseases. By measuring the displacement at
multiple parts of the human body, pulse wave velocity can be estimated from the
pulse transit time. This paper proposes a technique for signal separation using
an antenna array, so that pulse wave propagation can be measured in a
non-contact manner. The body displacements due to the pulse wave at different
body parts are highly correlated, and cannot be accurately separated using
techniques that assume independent or uncorrelated signals. The proposed method
formulates the signal separation as an optimization problem, based on a
mathematical model of the arterial pulse wave. The objective function in the
optimization comprises four terms that are derived based on a
small-displacement approximation, unimodal impulse response approximation, and
a causality condition. The optimization process was implemented using a genetic
algorithm. The effectiveness of the proposed method is demonstrated through
numerical simulations and experiments.
