Compact dual-band four-port MIMO patch antenna with inverse U-shaped resonators and defected ground structure for wireless communication applications

Abstract A compact four-port multiple-input multiple-output (MIMO) staircase rectangular patch antenna with inverse U-shaped resonators and a modified defected ground structure (MDGS) is presented for dual-band wireless communication applications. The antenna integrates four identical radiating elements placed orthogonally to achieve low mutual coupling and enhanced diversity. Fabricated on an FR-4 substrate with dimensions of 38 × 38 × 1.6 mm 3 , the design operates over two bandwidths (|S₁₁|< − 10 dB) of 6.8–8.9 GHz and 10.3–12.0 GHz, resonating at 7.9 GHz and 11 GHz, respectively. The structure achieves peak gains of 7.36 dBi and 5.82 dBi. MIMO performance is validated with an ECC below 0.01, DG greater than 9.95 dB, CCL below 0.02 bits/s/Hz, isolation exceeding 25 dB, mean effective gain (MEG) between − 9 dB and − 6 dB, and low TARC values. Simulated and measured results exhibit strong agreement, confirming the antenna’s potential for compact high-performance wireless devices within micro- and nanoscale integrated systems. The proposed design addresses key challenges in MIMO systems, such as minimizing mutual coupling, achieving wide dual-band operation, and maintaining compact size for integration in modern wireless devices.