A Wideband Automotive 4x4-MIMO 5G Antenna System with Wide Double-Stage Decoupling Circuit for a Double Shark Fin Cover

In order to generate more data throughput in the 5th generation for mobile communications, more antennas per volume are generally required. This leads to smaller spacing of the antennas in MIMO systems and higher coupling values, especially in the automotive sector. In the following, a symmetrical 4x4 MIMO antenna system with a new decoupling network is presented, where each antenna performs in a low frequency band from 617 MHz to 960 MHz and the higher bands from 1.7 GHz to 5 GHz. The decoupling network is designed in two stages for an exceptionally high bandwidth. The network is exclusively realized by quasi-lossless devices such that the total efficiency of the pure antenna system is even increased by the network at the lowest frequency. This approach achieves decoupling values of better than -14 dB and matching values of better than -6 dB in the entire low band. In the high band, decoupling values of better than -17 dB and matching values better than -10 dB are achieved.