Dynamic co-polarization decoupling method using tunable resonators

A novel method of decoupling two closely placed co-polarized antennas is presented in this work. Two co-polarization monopoles are placed at the same elevation with a distance of 0.8 λ. Eight rows of varactors based tunable resonators are placed between them. By tuning the bias voltage of the eight rows, the amplitude and phase responses are altered. Correspondingly, the near field distribution is manipulated. Thus a high-level port to port isolations is realized. The measured results show that the transmission coefficient is suppressed to -110 dB, when the direct transmission coefficient (nothing is between the monopoles) is about -27 dB, and when a same dimension metal plate is installed it is -50.0 dB. Furthermore, this high-level isolation is tunable. We realize similar results from 2.0 GHz to 2.6 GHz.