Miniaturized four port MIMO antenna for automotive communications

This paper presents the design, fabrication and testing of a novel circular slot antenna with an arc-shaped feed line for industrial scientific and medical (ISM) applications. The antenna is developed on a flexible, low loss substrate with a small footprint of 15 × 15 mm2. The proposed antenna is evolved from an arc slot radiator operating at 4.5 GHz. The structural modifications are performed to decrease the operating frequency to 2.45 GHz without increasing the antenna footprint. The antenna element is replicated along the four sides to develop a four-port MIMO antenna. The performance of the MIMO antenna is evaluated and the results are presented. The MIMO metrics such as Envelope Correlation Coefficient (ECC), Diversity Gain (DG) and Mean Effective Gain (MEG) are calculated and presented for isotropic, semi-urban and urban vehicular scenarios. The prototype MIMO antenna is fabricated and tested in real-time. The on-car performance of the antenna and the MIMO metrics computed indicate that the proposed antenna is suitable for automotive wireless communications.