Low‐profile wideband four‐element MIMO array using Giuseppe Peano AMC surface with improved efficiency and isolation for WLAN systems

Abstract

AbstractA low profile four‐element multiple‐input multiple‐output (MIMO) array of printed dipole antenna (PDA) backed by second iteration of Giuseppe Peano fractal artificial magnetic conductor (AMC) is introduced for broadband wireless communications. First, a suggested PDA with a pair of microstrip E‐shaped dipoles excited by an E‐shaped microstrip feedline is used to expand the bandwidth in the range of 5.47–6.92 GHz (S11 ≤ −10 dB). Then, the suggested 4 × 4 Giuseppe Peano fractal AMC reflector is loaded into the PDA to exhibit −10 dB measured impedance bandwidth from 4.21 to 7.06 GHz (50.61%) for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications. The proposed four‐element MIMO array loaded by 6 × 6 AMC reflector with diverse polarizations of elements introduces a low profile wideband structure. The measured results of four elements include the broad bandwidths from 4.3 to 7.05 GHz with enhanced gains (more than 8 dBi) and high efficiencies. The high isolations between the four elements with diverse polarizations are obtained larger than 26.5 dB and they reach 66 dB over the operating bandwidth for MIMO systems. The suggested PDA with AMC compared to the PDA without AMC exhibits a size reduction of 51.33%, enhanced radiation efficiency up to 94%, and excellent impedance matching with uni‐directional radiation patterns.