A compact planar UWB MIMO diversity antenna with Hilbert fractal neutralization line for isolation improvement and dual band notch characteristics

Abstract

In this communication a compact printed CPW-fed dual band-notched Ultra Wideband (UWB) Multiple Input Multiple Output (MIMO) antenna is exhibited. The UWB MIMO antenna consists of two planar identical monopole elements PPM1 and PPM2 respectively and a novel modified 2nd order Hilbert fractal shaped neutralization line (NL) is introduced along with a modified circular defect in the common ground plane. Modified Minkowski boundary fractal geometry is introduced on the top edges of the respective monopoles for reinforcing the isolation of the MIMO system. The fractal shaped neutralization line serves two purposes isolation improvement as well as band notching the Wi-Max band. Notch bands encompassing 3.3-3.8 GHz Wi-MAX and 3.7-4.2 GHz C-Band are acquired by the introduction of the Hilbert fractal neutralization line and etching rectangular slots on the ground structures. The antennas Ultra wide bandwidth ranges from 3.05 GHz to 13.5 GHz (VSWR ≤ 2). The radiator and ground plane of the antenna are realized with an overall size of 26.75 mm × 32.94 mm. It can be also observed that the spacing between the elements is astonishingly reduced to 0.52 mm which is least as per the knowledge of the authors in UWB MIMO antenna designs proposed in the existing literature. The agreement between the various simulation results advocates that the intended antenna can be a worthy candidate for various UWB communication systems. All the simulated results depict that the proposed UWB MIMO antenna is a promising candidate for portable UWB as well as UWB MIMO systems.