Title: Power Constrained Space-Time Processing for
Suppression of Electromagnetic Fields
Authors: Tommy Hult, Abbas Mohammed
Abstract: Active suppression of noise and vibrations is a well
established field of research with many applications in acoustic and mechanical
industries. In this paper we investigate the possibility of applying these
adaptive active control methods with the aim of lowering the electromagnetic
field power density at a specific volume in space using the superposition
principle and space-time processing employing the full MIMO (Multiple Input
Multiple Output) antenna system setup. The application that we evaluated is a
model of a mobile phone equipped with one ordinary transmitting antenna and two
actuator-antennas which purpose is to cancel out the electromagnetic field at
the human head while maintaining a predefined level of the overall output power
of the system. This power control is achieved through the use of a quadratic
constraint on the active control algorithm. Simulation results show the promise
of using the adaptive control algorithms and MIMO system to attenuate the
electromagnetic field power density.