Triple-band dual-antenna decoupling system for mobile handset

A low profile, triple band standard coverage, and multiple-input-multiple-output (MIMO) antenna system is proposed for mobile application in this work. The main objective of the study presented in the article is to reduce the coupling between the different access ports of the antennas to reduce the correlation between the signals received by them in a MIMO scheme. The MIMO antenna system consists of two Inverted F Antenna (IFA) multiband elements for 4G standard, covering different bands between 1720 and 2690 MHz, reused in 5G standards. This integrated MIMO antenna system is fabricated on a FR4 substrate with ɛr equal to 4.5. The dimensions of the board are equal to 130x60x1.54 mm3, which is a typical backplane of a mobile handset. The study includes two different distributions of the MIMO antennas in a handset, one of them with the antenna located in a co-polar configuration and the other in cross-polar configuration. In each of them, the improvement in performance is evaluated by adding a decorrelation network. The innovative solution for the decoupling network consists of adding frequency-selective branches that include the reactive element, between the power ports of the antenna, which will act as a frequency-selective decorrelator.