Compact quasi-elliptical-self-complementary four-port super-wideband MIMO antenna with dual band elimination characteristics

In this paper, a compact coplanar waveguide (CPW)-fed quasi-elliptical-self-complementary antenna (QESCA) exhibiting super-wideband (SWB) characteristics with dual-band notches for four-port multiple-input-multiple-output (MIMO) systems is presented. In order to achieve better inter-element isolation and polarization diversity, the four radiating elements of the MIMO antenna are placed orthogonal to each other. Each MIMO antenna element has an elliptical shape conductor patch and a slot, which is a complement of similar shape, both present on the same side of the substrate. At each port, the proposed antenna shows excellent SWB characteristics (1.25–40 GHz), providing a bandwidth ratio of 32:1. Further, two independent slits are loaded on each antenna element to reject Wi-MAX (3.5 GHz) and WLAN (5.5 GHz) bands from SWB. Inter-element isolation of more than 18 dB up to 15 GHz and over 25 dB in the higher frequency range is obtained. Measured parameters of the fabricated MIMO antenna prototype are in good agreement with the simulated results.