Experimental Studies on Radiation Intensification in Gigahertz Radio Frequency Band by Subwavelength Plasma Structures

Plasma-added intensification of radio frequency (RF) signals toward the future generation of compact antennas with wide-range requests has been studied experimentally in this paper. A technology based on modulation and enhancement effects of subwavelength plasma structures on application-focused RF electromagnetic radiation is developed. An inductively coupled plasma is applied to provide appropriate subwavelength structures, aiming at enhancing the electromagnetic radiation of an omnidirectional ellipse dipole antenna. The plasma mediated radiation enhancement on RF antenna signals of ~1 GHz is observed experimentally for the first time. It is shown that this technology is capable to obtain a significant gain up to nearly 10 dB higher than the free-space radiation without the plasma structure. And an enhanced frequency band of the typical GSM900 frequency range can be extended from 0.89 to 1.05 GHz. Meanwhile, electromagnetic signals transmitted by the plasma-added antenna still maintain good quality for communication. In addition, numerical simulations are also taken to reveal the mechanism of the radiation enhancement effects.