Intensification of microwave radiation by hybridized plasmon effect

In recent years, an innovative technology based on modulation and enhancement effects of subwavelength plasma on RF electromagnetic radiation has been proposed, in which the microwave radiation from an electrically small antenna can be significantly enhanced when the antenna is tightly enclosed by a subwavelength overdense plasma shell. But the exact mechanism is still not entirely clear. In this paper, we first use the theory of hybridized Local Surface Plasmon Resonance (LSPR) for visible light in nanometal to explain this cross-domain work of microwave radiation enhancement modulated by a subwavelength overdense plasma layer, and the results show that the LSPR frequency is in good accordance with the frequency of enhanced radiation signals. Furthermore, the relationship between LSPR and antenna impedance as well as their effects on the impedance matching condition between antenna and power supply are investigated. It is indicated that LSPR on the plasma layer changes the impedance of the antenna, which produces circuit resonance (differing from plasmon resonance) between the antenna and power supply, and thus more power is radiated from the power supply to free space.