In this paper, investigations of surface PiN diodes developed for a reconfigurable plasma antenna have been described. To increase carrier concentration within the surface PiN diodes as much as possible, parameters of the plasma region have been extensively discussed. According to these studies, it has been found that the average carrier concentration within the 'i' region has been achieved the level of 1018 cm(-3) at forward bias of 2 V. The carrier concentration becomes larger when the length and width of the 'i' region are reduced. Furthermore, a novel frequency reconfigurable antenna based on SPiN diodes is presented at Ku-band. The resonance frequencies at 13.71 GHz, 15.17 GHz, and 17.81 GHz have been easily achieved by turning on or off different sections of the antenna. The radiation efficiencies of the antenna are 79.70%, 80.70%, and 81.70%, respectively. Experimental results shown in this paper confirm the usefulness of the PiN diode's application within a plasma antenna and other semiconductor fields.