The Multiband Antenna Tuned by Plasma

We have fabricated a multiband antenna consisting of a half-wavelength antenna and eight plasma rings with five operating windows. It is also demonstrated that the shape and the number of plasma rings determine the value of return loss and the number of operating windows. Besides, the proposed antenna is tunable because the plasma can be actively tuned by the applied voltage. These results present a novel approach to enhance and manipulate the radiation of the multiband antenna based on plasma.