Communications methods, methods of forming a reader, wireless communications readers, and wireless communications systems are described in some embodiments. The jacket comprises at least inner layer, an intermediate layer attached to the inner layer, and an outer layer attached to the intermediate layer. The method and system identify whether the frequency peak is related to one of an overtone frequency, a subharmonic frequency, a higher harmonic frequency, or a side-shifted frequency of the oscillations of the different group of ions.