Utilization of antenna arrays in HF systems.

Different applications of radio systems are based on the implementation of antenna arrays. Classically, radio direction finding operates with a multi channel receiving system connected to an array of receiving antennas. More recently, MIMO architectures have been proposed to increase the capacity of radio links by the use of antenna arrays at both the transmitter and receiver. The first part of this paper describes some novel experimental work carried out to examine the feasibility of applying MIMO techniques for communications within the HF radio band. A detailed correlation analysis of a variety of different antenna array configurations is presented. The second section of the paper also deals with HF MIMO communications, focusing on the problem from a modelling point of view. The third part presents a sensitivity analysis of different antenna array structures for HF direction finding applications. The results demonstrate that when modelling errors, heterogeneous antenna arrays are more robust in comparison to homogeneous structures