A compact quad element MIMO-UWB antenna with band notch characteristics and high isolation

Abstract

This work presents a compact MIMO UWB antenna with WiMAX band-notch characteristics designed and inves- tigated. The proposed MIMO antenna comprises four unit cell antennas, each consisting of a microstrip feed line and a partial ground plane, with the radiators placed perpendicular to each other. A single antenna features a trapezoid- semicircle hybrid patch fed by a 50 O microstrip line, along with a partial ground plane, is initially designed for UWB applications, operating within 3.18–18.63 GHz. An inverted T-shaped stub is subsequently implemented to optimize the antenna for WiMAX band rejection at 3.3–3.8 GHz. Furthermore, a 2 × 2 MIMO antenna is designed utilizing the polarization diversity technique. The two radiating elements are placed orthogonally, with a decoupling structure positioned between them to improve isolation performance. Finally, the compact four-port MIMO antenna prototype is constructed on the FR4 substrate, with overall dimensions of 42 × 42 × 1.63 mm³. The proposed four-port MIMO antenna design offer s abandwidt ho f2.94–2 0GHz. The antenna’s isolation is <-1 8dB, and it maintains relatively stable radiation characteristics and gain, along with a lower envelope correlation coefficie nt(E C C<0.0055).