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Directional modulation (DM) can be regarded as a new frontier in physical layer communication security. This new technique uses an antenna array as a spatial encryption system which partitions the surrounding space into regions where the transmission is either perfectly intelligible or intentionally obfuscated. Still, energy and spectral efficiencies of current DM systems as well as their cryptographic robustness lag behind the modern performance standards in cryptography and radio-communication. This contribution proposes a generalization of the DM concept which overcomes the limitations of its initial formulation by making it both compatible with state-of-art digital modulations and cryptographically secure. Numerical analyses as well as real-world, high bit-rate implementation results are presented in support of the proposed approach.

This paper deals with the problem of analyzing the RADAR scattering from small constructive details on low RCS platforms. Starting from the ILDC formulations of gaps and cracks, as proposed by Shore-Yaghjian and other authors, we have generalized its applicability exploiting numerical results arising from 2D simulations. The procedure is simple and straightforward and allows the analysis of shapes whose analytical results are not available. Typical application examples are door enclosures, gaskets, or quasi planar geometries with discontinuities in electrical conductivity and so on. This process, useful in preliminary design phases, dramatically reduces the simulation times, therefore allowing to analyze a lot of different situations. Validations have been performed resorting to numerical simulations as well as measurement activities. Results are provided for some simple cases, describing the capabilities and limitations of the approach. Comparisons between simulated and measured results on proper mock-up will be shown in the Conference presentation.