Generalized Isolation Between Antennas for EMC Problems in Complex EM Environments

Currently, the complex information platforms are characterized by being full of antennas. In order to keep all these antennas working normally, the isolation between them have to reach a given index. This paper introduces a generalized theory of S-parameters and based on which, the generalized partitioned S matrix is developed to study the isolation between antenna groups where the frequencies of receiving antennas are different from those of emission antennas. It is pointed out in this paper that, to achieve given isolation index, three aspects must be considered, that is, the designing of the antennas, the selecting of the polarization, and the out-band isolation network for receiving antennas. Practical approximant formula for isolation and examples are presented.