Novel Ultra-Compact Two-Dimensional Waveguide-Based Metasurface for Electromagnetic Coupling Reduction of Microstrip Antenna Array

摘要

A novel ultracompact two-dimensional (2D) waveguide-based metasurface isrnproposed herein and applied for the first time to reduce mutual coupling in antenna arrayrnfor multiple-input multiple-output applications. The unit cell of the proposed 2D waveguidebasedrnmetasurface is ultracompact (8.6 mm 3 4.8 mm, equal to k0/14.2 3 k0/25.5) mainlyrndue to the symmetrical spiral lines etched on the ground. The metasurface exhibits arnbandgap with two transmission zeros attributing to the negative permeability in the vicinityrnof magnetic resonance and the negative permittivity in the vicinity of electric resonance.rnTaking advantage of these two features, a microstrip antenna array is then designed, fabricated,rnand measured by embedding an 8 3 1 array of the well-engineered 2D waveguidebasedrnmetasurface elements between two closely spaced (9.2 mm, equal to k0/13.3) H-planerncoupled rectangular patches. There is good agreement between the simulated and measuredrnresults, indicating that the metasurface effectively reduces antenna mutual coupling byrnmore than 11.18 dB and improves forward gain. The proposed compact structure has onernof the highest reported decoupling efficiencies among similar periodic structures with comparablerndimensions.