Enhancement of decoupling bandwidth in very dense dipole arrays with split-loop resonators

We report a qualitative broadening of the operation band in a very dense dipole array using passive split-loop resonators as decoupling elements. In comparison with the previously reported technique, where the decoupling in an array of three active dipoles was achieved by two passive dipoles, the bandwidth enhances drastically - from 0.5% to 8% at the same level of decoupling specified as -8 dB for the cross-talk transmittance. The reason of this huge band broadening is the birefringence of the resonant electromagnetic interaction of the decoupling scatterers that occurs in two overlapping bands. Analytical estimations help us to locate the decoupling regime on the frequency axis. Full-wave numerical simulations of the decoupling regime are validated experimentally.