Isolation Improvement of MIMO Antenna Using a Novel Flower Shaped Metamaterial Absorber at 5.5 GHz WiMAX Band

• Published in: IEEE transactions on circuits and systems. II, Express briefs Vol. 67; no. 4; pp. 675 - 679
• Main Authors: Garg, Priyanka, Jain, Priyanka
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.04.2020; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Absorbers; Absorbers (materials); Absorption; Absorptivity; Antennas; Correlation coefficients; Impedance; isolation; Magnetic materials; Metamaterial absorber; Metamaterials; MIMO (control systems); MIMO antenna; MIMO communication; mutual coupling reduction; Patch antennas; Resonant frequencies; Resonant frequency; Substrates; WiMAX
• ISSN: 1549-7747; 1558-3791
• DOI: 10.1109/TCSII.2019.2925148

This brief demonstrates the use of metamaterial absorber (MA) to achieve high isolation between two patch antennas in a 2-element multiple-input-multiple-output (MIMO) system operating at 5.5 GHz resonant frequency useful for WiMAX application. The proposed flower shaped MA, designed on a 9 × 9 mm 2 FR-4 substrate with 1 mm thickness, exhibits near unity normalized impedance at 5.5 GHz with an absorptivity of 98.7%. A four element array of the MA is arranged in the form of a line in the middle of the two radiating patches in order to suppress the propagation of surface current between them at the operating frequency. Using the proposed flower shaped MA, an isolation of nearly 35 dB is achieved. The MIMO structure is studied in terms of return loss, isolation, overall gain, radiation pattern, envelope correlation coefficient (ECC), diversity gain (DG), total active reflection co-efficient (TARC), etc. The structure is finally fabricated and measured to show good agreement with the simulated results.