MIMO ANTENNA FOR BLUETOOTH, WI-FI, WI-MAX AND UWB APPLICATIONS

Abstract

A Multiple Input Multiple Output (MIMO) antenna consisting of two 90 - angularly separated semicircular monopoles with steps for Bluetooth, Wi-Fi, Wi-MAX and UWB applications is proposed. Initially, an array of two coplanar circular monopoles with element separation of 25mm is investigated. In this conflguration, mutual coupling is < i5dB and < i10dB over 2GHz{3GHz and 3GHz{10.6GHz, respectively. Mutual coupling is reduced by using 90 - angularly separated semicircular monopoles. With semicircular conflguration, though the mutual coupling is improved, impedance bandwidth is reduced due to reduction in electrical length. A step like structure is introduced in the semicircular monopoles, and ground plane is modifled and extended between the two elements to improve the impedance bandwidth and mutual coupling. Impedance bandwidth from 2.0GHz{10.6GHz with S21 < i20dB and i14dB is achieved over 3.1GHz{10.6GHz and 2.0{3.1GHz respectively. The antenna is fabricated using 46mm £ 37mm RT Duroid substrate. Measurement results agree with the simulation ones. Radiation patterns are stable, and correlation coe-cient is < 0:02 over 2.0{10.6GHz.