Metamaterial-Based Four-Port Polarized MIMO Antenna for SWIPT Applications

This paper presents a low-profile, single-layer wideband metamaterial-inspired linear polarized multiple-input multiple-output antenna array with an integrated rectifier for simultaneous wireless information and power transfer applications. The antenna consists of eight elements fabricated on Rogers 4350 substrate with a defected ground structure, where four ports are dedicated to wireless information transfer and four ports are directly connected to a rectifier for wireless power transfer. The rectifier employs four SMS7630 diodes and is directly matched to the antenna with input impedances of 34−j57 Ω and rectifier impedance of 34+j57 Ω, delivering 0.9 V output voltage with 75% efficiency into a 1000 Ω load. The total array occupies 0.59λ × 0.33λ, operating over 3.2-4.3 GHz, with a peak gain of 5.5 dBi and isolation below −20 dB between all ports. Metamaterial-inspired elements enhance impedance and bandwidth, providing stable polarization. MIMO performance is evaluated via envelope correlation coefficient, diversity gain, and mean effective gain, confirming suitability for SWIPT-enabled sensors, IoT devices, and other low-power wireless systems.