A Method of Reducing Coupling between PIFAs Using Cross Slot Defected Ground Structure

This is the authors' abstract. We don't add key points for this paper.

To reduce the coupling between closely packed antenna elements in multiple-input multiple-output (MIMO) systems, a method is proposed to reduce the coupling between planar inverted F-shaped antennas (PIFAs) by using cross slot defected ground structure (CSDGS). This structure includes four intersecting slits etched into the ground plane. The resonant frequency of the PIFA is within the bandgap of the CSDGS, effectively suppressing surface waves and reducing the coupling between antennas. Through simulation, it is demonstrated that the proposed structure achieves more than 35 dB isolation between two antenna elements. To validate the effectiveness of the method, the circuit of the simulated structure is processed and measured using a vector network analyzer. The measured results align closely with the simulated ones, confirming the viability of the proposed method. The parameter study and correlation coefficient of CSDGS are also analyzed.