A novel MIMO antenna with switchable UWB/5G modes for vehicular terminals

Abstract

AbstractThis paper demonstrates the design and development of a dual‐operating mode multiple‐input and multiple‐output (MIMO) antenna. The MIMO antenna comprises a novel ultrawideband (UWB) antenna with selectively chosen feedlines to obtain bandwidth reconfiguration. The novel UWB monopole evolved from a rectangular monopole whose radiating portion and the ground plane are shaped to obtain broadband impedance matching from 2.3 to 10.7 GHz (Mode 1). The antenna is excited using a 50‐Ω microstrip line. An additional feed path is created and deployed to achieve bandwidth selectivity with a tuning fork bandpass filter (BPF) operating between 2.8 and 4 GHz. Bandwidth selection is performed using a pair of positive–intrinsic–negative diodes. Thus, in the reconfigured state, the monopole is connected to the excitation source through the BPF, restricting the operational bandwidth to 2.8–4.0 GHz (Mode 2). A vertically polarized four‐element MIMO antenna with pattern diversity characteristics is constructed, and the performance parameters are studied. The proposed multiantenna is fabricated and tested in the laboratory. The proposed MIMO antenna offers a measured gain of over 3.51 dBi and total efficiency above 78%. The proposed multielement antenna is suitable for UWB communications, including ISM, LTE2700, and sub‐6 GHz 5G communications at 3.5 GHz in the vehicular environment.