Symmetric Residual Current Cancellation (SRCC) Method for Single-Band and Multi-Band Shared-Aperture Antenna Arrays Decoupling

This paper proposes a novel symmetric residual current cancellation (SRCC) method for differentially-fed antennas (DFAs) decoupling. Unlike conventional approaches that minimize coupling currents, SRCC allows residual currents on the coupled antenna but ensures they are identical at the two differential ports. These currents cancel out after passing through the differential power divider, achieving high isolation and significantly improving decoupling bandwidth. More importantly, the SRCC introduces a new decoupling condition that is easier to satisfy using simple structures, thereby enabling the realization of multi-band shared-aperture patch arrays. A dual-band shared-aperture patch array were developed, in which both in- and cross-band couplings across multiple frequency bands are addressed using an All-in-One decoupling network. Both the radiators and the decoupling networks are aperture sharing, enabling compact integration.