High-isolation quad-port mmWave MIMO antenna with hybrid decoupling structure for V2V applications

• A quad-port mmWave MIMO antenna is designed to function between 24.6-31.8 GHz. • A hybrid decoupling structure is presented to improve isolation. • The designed antenna is comprehensively analyzed for V2V applications. This work presents the design and performance evaluation of a quad-port compact millimeter wave (mmWave) MIMO antenna with integrated isolation and diversity enhancement features using a hybrid decoupling structure for Vehicle-to-Vehicle (V2V) communication in 5G and beyond applications. The proposed mmWave MIMO antenna operates efficiently in the frequency range of 24.6-31.8 GHz with a peak gain of 8.1 dBi. The mutual coupling between the antennas in MIMO is effectively reduced by employing orthogonal antenna orientation and a defected ground structure (DGS) as a hybrid decoupling structure, ensuring isolation greater than 22.5 dB across the operating frequencies. Furthermore, the antenna exhibits strong MIMO diversity metrics, with an ECC of less than 0.007, a DG close to 10, an MEG of less than -3, a TARC lower than -10 dB, and a CCL of less than 0.25 bps/Hz, affirming its suitability for multi-antenna systems. The performance characteristics of the proposed mmWave MIMO antenna are used for analyzing the Alpha-Beta-Gamma (ABG) path loss model, incorporating the Rician fading model to simulate the large and small scale effects in realistic environments. The simulation findings indicate strong signal strength, channel capacity, and route loss performance across a variety of scenarios, including metropolitan streets, tunnels, highways, and parking lots, as well as harsh weather situations such as moderate to heavy rainfall. The antenna maintains consistent link performance despite significant Doppler shifts and non-line-of-sight (NLOS) propagation, making it ideal for ultra-reliable low-latency communication (URLLC) in dynamic V2V networks. The proposed mmWave MIMO antenna provides a compact and effective solution for next-generation vehicular communication systems that require high isolation, gain, and resilience to channel degradation.