volume | PIER Journals

Abstract

This paper presents a compact dual-band reconfigurable MIMO antenna array that simultaneously addresses the challenges of frequency agility and strong inter-element coupling in densely integrated antennas. The proposed antenna element employs a slit-loaded microstrip patch combined with a varactor diode to achieve continuous tuning of the high-frequency band while maintaining a stable low-frequency resonance. To suppress the severe mutual coupling typically induced by reconfigurable structures, an optimized etched ground-plane topology featuring branched Π-shaped slots is introduced. This isolation structure effectively alters surface-wave propagation paths and attenuates coupling fields, resulting in a significant improvement in port-to-port isolation across both operating bands. Comprehensive parametric studies validate the effectiveness of the slot configuration in enhancing decoupling performance under various tuning states. A 1×4 MIMO array prototype was fabricated and experimentally evaluated, showing good agreement with simulations. Measurements demonstrate wide-range high-band tuning from 3.6 to 4.2 GHz, stable low-band operation near 2.3 GHz, improved radiation efficiency, and low envelope correlation coefficients, confirming strong diversity performance. Owing to its compact structure, stable dual-band characteristics, and robust reconfigurability, the proposed design offers a promising solution for adaptive and space-constrained modern wireless communication systems.

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Dr. Jie Sun

Dr. Hucheng Sun

Dr. Yan Li