Conjoined Yet Decoupled Wideband Multiantenna MIMO Linear Patch Array

A conjoined yet decoupled wideband multi-antenna MIMO linear patch array (LPA) based on using a wideband patch antenna with dual slanted (±45°) shorting metal walls as a building antenna unit (BAU) is presented. The BAU alone can have a very wide operating band of larger than 4 GHz (about 3.25-7.40 GHz, a fractional bandwidth of about 78%). Owing to the antenna’s dual shorting metal walls, it allows arbitrary antenna units to be directly connected in series into a linear patch array with high port isolation (>20 dB) over the very wide band, with no additional decoupling elements required. A four-antenna LPA constructed by using four BAUs is demonstrated. In addition to the high port isolation, the four-antenna LPA can generate four uncorrelated waves with their measured envelope correlation coefficients (ECCs) less than 0.03 over the very wide band almost same as that of the BAU alone. In addition, the proposed MIMO LPA has an all-metal structure, with no substrate materials required. The obtained results make it promising for MIMO access-point application to cover the 5G band of 3.3-5.0 GHz and the unlicensed or mobile band of 5.925-7.125 GHz. Details of the BAU-based wideband multi-antenna MIMO LPA and the experimental results of the four-antenna LPA are presented.