Figure 8a compares measured and simulated reflected S-parameters and Figure 8b compares measured and simulated transmitted S-parameters for the 4 × 4 SN MIMO antenna. The measured 10 dB impedance bandwidth of 4.25 percent and Port 1 isolation agree closely with the simulation. In the case of the measured data, both |S12| and |S13| exhibit values below -20 dB, while |S14| is lower than -40 dB.

Figure 8

Figure 8 (a) 4 x 4 SN MIMO antenna measured and simulated reflection coefficients. (b) 4 x 4 SN MIMO antenna measured and simulated transmission coefficients.

Figure 9

Figure 9 Simulated and measured 4 x 4 SN MIMO antenna ECC.

SN MIMO ANTENNA DIVERSITY ANALYSIS AND PERFORMANCE

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The practicality of a MIMO antenna system relies on its ability to provide effective diversity performance. To assess this, ECC is used as a measure; a low ECC implies a significant degree of isolation between antennas. Far-field antenna characteristics are used to determine the ECC using Equation 1.12

Notably, when applied to outdoor scenarios, the SN MIMO antenna simulated and measured ECC value consistently falls below 0.001, as shown in Figure 9. This value indicates minimal mutual coupling between antenna elements.

Figure 10

Figure 10 Simulated and measured 4 x 4 SN MIMO antenna CCL.

Figure 11

Figure 11 4 x 4 SN MIMO antenna TARC.

In MIMO, CCL is a measure of the channel capacity loss experienced by the four-port MIMO antenna array due to correlation effects when used in vehicles. The quantification of CCL is based on Equation 2:12

Where:

ΨR is the receiving antenna’s correlation matrix and it is expressed as Equations 3 to 7:

Where:

In industrial and vehicular communication contexts, a CCL below 0.4 b/s/Hz is considered good. This antenna’s CCL is shown in Figure 10. These results indicate minimal correlation impact and a high data transfer rate.

The total active reflection coefficient (TARC) provides insight into signal quality and reflection, helping to optimize antenna design, mitigate interference and ultimately contribute to reliable and high performance MIMO communication. It is determined with S-parameters using Equation 8.12

Sin denotes the reflection coefficients between distinct antenna ports. Figure 11 shows TARC curves depicting different phase combinations. For the efficient performance of MIMO systems in V2V, it is important that TARC values consistently remain below -10 dB within the specified frequency range.

Figure 12

Figure 12 (a) 4 x 4 SN MIMO Antenna 1 simulated and measured radiation patterns at 3.5 GHz. (b) 4 x 4 SN MIMO Antenna 2 simulated and measured radiation patterns at 3.5 GHz. (c) 4 x 4 SN MIMO Antenna 3 simulated and measured radiation patterns at 3.5 GHz. (d) 4 x 4 SN MIMO Antenna 4 simulated and measured radiation patterns at 3.5 GHz.

Figure 12a to Figure 12d show the 2D radiation patterns at 3.5 GHz for Antenna 1 to Antenna 4, respectively. The E-plane patterns are similar between Antennas 1 and 2 and Antennas 3 and 4. Likewise, in the H-plane, the patterns between Antennas 1 and 4 and Antennas 2 and 3 are similar. This ensures there are no interference issues during reception and demonstrates good radiation patterns in both planes.

Table 2 compares this work with similar works. It highlights this antenna’s ECC bandwidth, spanning the 5G vehicular communication and sub-6 GHz bands, as well as its compact structure. Additionally, it demonstrates exceptional values for CCL and TARC.

Table 2


CONCLUSION

A low-profile MIMO microstrip patch antenna featuring dual slots and notches is introduced and optimized for 5G V2V communication. The proposed design, operating at 3.5 GHz, exhibits a bandwidth of 150 MHz, an important requirement for intelligent transportation systems. A gain greater than or equal to 5 dBi is realized within the frequency band. Through simulation and measurement, the antenna’s performance metrics, including ECC, CCL, TARC, MEG, radiation patterns and efficiency are analyzed. The ECC is below 0.001, surpassing previous research benchmarks. Its compact form factor, good radiation characteristics and low ECC make this design suitable for vehicular communication, WiMAX and sub-6 GHz applications.

References

  1. R. Praveena, T. R. Ganesh Babu, G. Sudha, N. Mahesh, J. Ganasoundharam and M. Birunda, “Design of Tilted E-Shaped Monopole Antenna for Vehicular Communication,” 8th International Conference on Smart Structures and Systems, April 2022.
  2. R. S. Chen, L. Zhu, S.W. Wong, X. Z. Yu, Y. Li, L. Zhang and Y. He, “Low-Sidelobe Cavity-Backed Slot Antenna Array with Simplified Feeding Structure for Vehicular Communications,” IEEE Transactions on Vehicular Technology, Vol. 70, No. 4, April 2021, pp. 3652–3660.
  3. T. Sasikala, R. Arunchandar, M. A. Bhagyaveni and M. Shanmuga Priya, “Design of Dual- Band Antenna for 2.45 and 5.8 GHz ISM Band,” National Academy Science Letters, Vol. 42, No.3, June 2019, pp. 221–226.
  4. S. Gao, L. Ge, D. Zhang and W. Qin, “Low-Profile Dual-Band Stacked Microstrip Monopolar Patch Antenna for WLAN and Car-to-Car Communications,” IEEE Access, Vol. 6, October 2018, pp. 69575–69581.
  5. H. Ozpinar, S. Aksimsek and N. T. Tokan, “A Novel Compact, Broadband, High Gain Millimeter-Wave Antenna for 5G Beam Steering Applications,” IEEE Transactions on Vehicular Technology, Vol. 69, No. 3, March 2020, pp. 2389–2397.
  6. J. Malik, D. Nagpal and M. V. Kartikeyan, “MIMO Antenna with Omnidirectional Pattern Diversity,” Electronics Letters, Vol. 52, No. 2, January 2016, pp. 102–104.
  7. G. Srinivas, D. Jabin and A. K. Singh, “Multiband MIMO Antenna with Reduction in Mutual Coupling and ECC,” Students Conference on Engineering and Systems, May 2014.
  8. A. Dkiouak, A. Zakriti, M. El ouahabi, H. Elftouh and A. Mchbal, “Design of CPW-Fed MIMO Antenna for Ultra-Wideband Communications,” Procedia Manufacturing, Vol. 46, May 2020, pp. 782–787.
  9. S. Arumugam, S. Manoharan, S. K. Palaniswamy and S. Kumar, “Design and Performance Analysis of a Compact Quad-Element UWB MIMO Antenna for Automotive Communications,” Electronics, Vol. 10, No. 18, pp. 2184, September 2021.
  10. S. Virothu and M. S. Anuradha, “Conformal MIMO Circular Polarization Diversity Antenna for V2X Applications,” International Journal of RF and Microwave Computer-Aided Engineering, Vol. 32, No. 4, December 2021.
  11. H. -T. Hu, F. -C. Chen and Q. -X. Chu, “A Wideband U-Shaped Slot Antenna and its Application in MIMO Terminals,” IEEE Antennas and Wireless Propagation Letters, Vol. 15, July 2016, pp. 508–511.
  12. B. M. Yousef, A. M. Ameen, A. Desai, H. -T. Hsu, V. Dhasarathan and A. A. Ibrahim, “Defected Ground Structure-Based Wideband Circularly Polarized 4-port MIMO Antenna for Future Wi-Fi 6E Applications,” AEU - International Journal of Electronics and Communications, Vol. 170, No. 2, July 2023.
  13. C.E. Guan and T. Fujimoto, “Design of a Wideband L-Shape Fed Microstrip Patch Antenna Backed by Conductor Plane for Medical Body Area Network,” Electronics, Vol. 9, No. 1, 2020.