The present work is divided in two parts, basically: 1) electronic Warfare - Chapter 1 2) The [W] Matrices - Chapters 2 to 5. The first part is aiming presenting an introductory text in Portuguese on Electronic Warfare (EW). The EW subject is generally discurssed and the Electronic support. Measures (ESM) are introduced. Electonic Counter Measures (ECM) and Electroni Counter-Counter Meassures (ECCM) are also focused. In the second part the [W] matrices are introduced. Based upon the Fast ourieer Transform algorithm certain correspondences batween these matrices and well-knoron microwaves circuits are noted. Form these analogies it is seen that those matrices may be easily assembled. Some of these circuits are manufactured and the results obtained are discurssed. Chapter 5 emphasises the utilization of [W] matrices on Direction Finders Systems (D/F). two different kinds of D/F systems are presented; respectively using linear and circular antenna arrays. Finnaly, Chapter 6 is devoted to the conclusions and suggestions for future studies on this area.