Modern Shielding Methods: On Applications of Space–Time Modulated Media

This article delves into the unique advantages of space–time modulated (STM) media for green shielding. An efficient optimization-based synthesis technique is introduced, leading to four shielding methods. The numerical results of the finite-difference time-domain (FDTD) method are validated by a conventional analytical method. Data preservation, high shielding effectiveness of at least 20 dB, and reflection reduction of at least 10 dB (green shielding) are achieved with upconversion, downconversion, diversion, and frequency distribution of the signal. This diverse output signal type and direction flexibility may be considered an additional special advantage of the investigated modern shielding methods. The energy conservation rule allows the designer to choose an appropriate truncation point. As a result, certain frequency components experience controlled amplified or attenuated propagation.