Secure Multi-Directional Independent Transmission Based on Directional Modulated 2D Conformal Phased Array

Directional Antenna Modulation (DAM) utilizing 2D conformal phased arrays has been demonstrated to enable secure Multi-directional Independent Transmission (MIT) over a broad angular range. This paper proposes an unbalanced DAM technique that dynamically allocates power according to transmission distance, thereby significantly enhancing transmission efficiency in practical scenarios where receivers are located at varying distances. In particular, a high-efficiency Differential Evolution (DE) optimization algorithm integrated with an "alien species invasion" mechanism is developed to accelerate convergence and optimize the phase delays of each array element. Bit Error Rate (BER) analysis for MIT reveals superior directional security compared to traditional methods, with conformal arrays providing wider angular coverage and spherical sparse arrays overcoming the half-wavelength spacing limitation. The simulation results validate that the proposed system achieves simultaneous secure transmissions in multiple directions while maintaining a BER below -40 dB.