Compact Dual-Band Balanced MIMO Antenna for Wi-Fi 6/6E Applications in Tablet Computers with Metal Housing

A compact dual-band balanced MIMO antenna is presented in this article for Wi-Fi 6/6E applications in metal-housed tablet computers. To address the challenges of small clearance and metal housing, a systematic evolution of the proposed design, derived from a slot antenna pair with zero edge-to-edge spacing, highlights four key contributions. Firstly, two balanced slot modes, are deliberately excited to support consistent coverage and maintain robust performance against environmental detuning. Secondly, coupled-loaded C-shaped rings (CSRs) are first employed to simultaneously achieve a 59.5% size reduction and generate a transmission zero (TZ) via Fano-type resonance in the 6-GHz band. Thirdly, an additional TZ is realized through modal cancellation, using a chip capacitor, to enhance isolation in the 5-GHz band. Consequently, dual-band coverage and decoupling across Wi-Fi 6/6E bands (5.15–5.83 GHz and 5.925–7.125 GHz) are achieved within a compact antenna footprint of 0.21×0.07 λ_L². Finally, an 8×8 MIMO antenna system prototype is fabricated and experimentally verified in a metal-housed tablet platform. Measured results confirm a –6 dB impedance bandwidth (IBW) from 4.3 GHz to 7.5 GHz. Within Wi-Fi 6/6E bands, measured total efficiency from 53.0% to 73.1% and isolation over 12.9 dB are obtained, with acceptable diversity performance.