Mutual Coupling Reduction Between Microstrip Patch Antennas Using Slotted-Complementary Split-Ring Resonators

TLDR

The authors propose a complementary split‑ring resonator (SRR) based structure to reduce mutual coupling between two coplanar microstrip antennas operating in the same frequency band. The structure comprises a unit cell with two complementary SRRs linked by an additional slot, whose band‑gap filtering characteristics are analyzed via dispersion analysis. This design achieves a 10‑dB reduction in mutual coupling at a quarter‑wavelength spacing, improves bandwidth and suppression, and offers broadband performance suitable for multiband antennas.

Abstract

A novel structure based on complementary split-ring resonators (SRRs) is introduced to reduce the mutual coupling between two coplanar microstrip antennas that radiate in the same frequency band. The new unit cell consists of two complementary SRR inclusions connected by an additional slot. This modification improves the rejection response in terms of bandwidth and suppression. The filtering characteristics of the band-gap structure are investigated using dispersion analysis. Using the new structure, it was possible to achieve a 10-dB reduction in the mutual coupling between two patch antennas with a separation of only 1/4 free-space wavelength between them. Since the proposed structures are broadband, they can be used to minimize coupling and co-channel interference in multiband antennas.