4-port UWB MIMO antenna with bluetooth-LTE-WiMax band-rejection and vias-MCP loaded reflector with improved performance

In this article, a 4-port MIMO antenna of dimension 0.46λ0× 0.46λ0× 0.01λ0 (λ0 is the lowest operating wavelength at 2.08 GHz) is proposed. It consists of array of fractal radiators sorted orthogonally with 0.05λ0 edge-to-edge separation and contorted feeds perform as impedance transformer. A centered π-shaped inverted-L notch asserts rejection at bluetooth-LTE-WiMax band. The MIMO configuration has common ground plane with no decoupling topology provides an inter-elemental port isolation > 15 dB. There are four vias-Metallic conducting probes (vias-MCP) connected to antenna ground and reflector. The conducting probes enroute the near-field currents from radiators and neutralize into the loaded reflector, with isolation improved > 20 dB and antenna performances are enhanced. The reflector has dimension 0.58λ0× 0.58λ0 fixed at Hair = 0.07λ0 (≈ 10 mm). The antenna operates from (2.08–10.4) GHz with band rejection at (2.27–3.62) GHz, asserts improved gain characteristics (7–9.57) dBi at pass band and −4 dBi at notched band. This new technique of vias-MCP in the proposed multi-port configuration mitigates mutual interaction of surface wave coupling on radiators, reduces near-field condensed currents and couplate the surface waves into the loaded reflector to improvise impedance matching and gain characteristics for UWB wireless communication systems.