Miniaturized High Gain Broadband 16-Element MIMO Array Using Planar Artificial Magnetic Conductor With Enhanced Isolation for WLAN/WiMAX Applications

A low-profile 16-element printed dipole antenna (PDA) array backed by a planar artificial magnetic conductor (AMC) is introduced for multiple-input multiple-output (MIMO) wireless communications. The proposed 16-element MIMO array loaded by a 13 x 13 AMC reflector with various polarized directions exhibits a low-profile wideband structure, which includes the broad measured bandwidths from 4.25 to 7.25 GHz with increased gains (>8 dBi) and high efficiency. The high isolation between the 16 elements with diverse polarizations is larger than 27 dB and reaches 67 dB over the operating band for MIMO systems. The suggested PDA with a microstrip V-shaped dipole excited by a V-shaped microstrip feedline is used to expand the broad simulated band spanning 5.34-6.70 GHz (S-11 =-10 dB). Moreover, the suggested 13 x 13 planar fractal AMC reflector is loaded into the PDA array to exhibit a reflection coefficient, S-11, of less than -10 dB across the band of 4.26-6.90 GHz for wireless local area network and worldwide interoperability for microwave access applications. The proposed design with AMC compared to the design without AMC exhibits a size reduction of 50.3%, increased gain up to 8.2 dBi, and excellent impedance matching with unidirectional radiation patterns. The novel AMC unit cell is realized based on the planar patch with inserted slots to operate at 6.10 GHz with an AMC band spanning 5.15-7.10 GHz (32%).