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

Abstract

For the fifth generation of mobile services (5G) compact solutions of 4x4 MIMO antenna systems are required fitting into mounting positions with small volume requirement. Herein we present a new set of four individual MIMO antennas which are arranged in a line of 19.5 cm length which can be integrated into one single shark fin antenna cover. The three larger antennas cover a frequency range from 617 MHz to 960 MHz (low band) and the four antennas cover the frequency range between 1.7 GHz to 6 GHz (high band). For increased performance in low band, antennas are connected via single-stage low-loss decoupling and matching circuits. With that, transmission factors of less than -14dB and reflection factors of -10dB are typically obtained in low band, while at band limits transmission factors of -11dB and reflection factors of -6 dB are not exceeded. In the high band, all antennas meet a -10 dB matching requirement and are well decoupled with less than -15dB. For the low band, the low loss decoupling- and matching-network even yields partly improvements in total efficiency. Simulated and measured results show the improvements due to the decoupling and matching network in good agreement.