Dear Rabin Kanisha

The mismatch between simulation and fabrication of a 4-port MIMO antenna in CST can often be attributed to manufacturing tolerances and material discrepancies. During simulation, ideal conditions, such as perfect conductor properties, uniform substrate thickness, and precise dimensions, are assumed. However, in fabrication, imperfections arise due to etching inaccuracies, variations in dielectric constant, or surface roughness of conductive materials. Even minor deviations in trace widths, feedline alignment, or substrate properties can significantly alter the antenna's performance, leading to shifts in resonant frequencies, impedance matching, or radiation patterns.

Another key factor is the impact of the measurement environment and setup, which differs from the idealized simulation conditions. In simulations, the antenna is modeled in free space or with perfect boundary conditions, while real-world measurements introduce external influences like cable interference, connector losses, or nearby objects causing parasitic coupling. Additionally, the port excitation in simulations may not perfectly match the actual feed network in the fabricated prototype, leading to differences in mutual coupling and overall system performance. These practical challenges highlight the need for iterative design adjustments to bridge the gap between simulation and reality.

I hope this helps.

Differences between antenna simulation and measurement results are mainly due to the use of idealized models in simulations, such as perfect conductors and homogeneous materials. In practice, factors like manufacturing tolerances, deviations in material properties, and physical imperfections can affect performance. Simulations are usually performed in infinite space or ideal anechoic environments, whereas measurements are influenced by environmental reflections, interference, nearby objects, and EMI. Impedance mismatches in feed lines, cable losses, and connector issues, which are not fully represented in simulations, can also impact measurements. Additionally, calibration errors of the network analyzer, limited frequency resolution, and convergence issues in numerical methods can contribute to simulation-measurement discrepancies.

Hello. In agreement with all of the above, specific conclusions can only be made by analyzing the antenna model and identifying critical geometry parameters in the antenna type.

Like virtual and reality. In simulation result is based on limited input while practically infinite factors affect the final result even its measuring equipment.

Hello,

In antenna design, the difference between simulation and design results is due to the insertion loss of SMA connectors. In this case, you need some professional help for connecting the antenna with SMA connections. Still, slight losses will be there in S11.

Thanks,

Félix Oscar Socorro Márquez Cem Güler Smrity Dwivedi Akhilesh Prasad Singh Ivan A. Illarionov I sincerely render my thanks for my question being answered. I still seek the extended support in answering the newly added question against section ii. Thanks in advance.