Isolation enhancement of patch antenna array via metamaterial integration

A high‐isolation coaxial‐fed antenna array is proposed through the integration of metamaterial. To this end, a magnetic metamaterial, the substrate‐integrated split‐ring resonator (SI‐SRR), is designed and integrated in the shared substrate between two closely spaced antennas. Due to negative permeability of SI‐SRR, magnetic fields are blocked in the shared substrate. By suppressing the near‐field magnetic coupling, enhanced isolation between the two antennas is obtained. The antenna array was fabricated and measured. Both the simulated and measured results show that the proposed antennas can provide an isolation of 34.5 dB in the operation band, even when the gap between the two antennas is only nearly about 0.033λ.