According to an embodiment, a plasma processing system includes a plasma chamber, an RF source, a matching circuit, a balun, and a resonating antenna. The resonating antenna includes a first and a second spiral resonant antenna (SRA), each having an electrical length corresponding to a quarter of a wavelength of a frequency of a forward RF wave generated by the RF source. The first end of the first SRA is coupled to a first balanced terminal of the balun and the second end of the first SRA is open circuit. The first end of the second SRA is coupled to a second balanced terminal of the balun and the second end of the second SRA is open circuit. The first and the second SRA are arranged in a symmetrically nested configuration having a same center point.