An electromagnetic field pattern measuring technique and its application to analysis of indoor electromagnetic field

As a technique for analyzing the electromagnetic (EM) environment, an EM-field-pattern measuring system was developed. This system was used to visualize an indoor EM field distribution as a multifrequency pattern in which the effect of reflected waves from walls could be observed. In order to eliminate or reduce the reflected waves, an algorithm consisting of a position estimation method and an intensity estimation method for equivalent reflected sources is realized by a combination of the maximum entropy spectral estimation and error reduction techniques. Simulations have shown its validity and that the positions of reflected sources could be estimated to within an error of 7%. The algorithm has been used to analyze indoor EM fields. For an EM field pattern measured in an ordinary room, the positions and intensity of equivalent reflected sources were estimated and the reflected waves were greatly reduced although they could not be completely eliminated.