Design and Simulation of Microstrip Patch Antenna 3.5 GHz, for 5 G Applications using CST Software

Abstract

this paper dives into designing and simulating a small rectangular micro-strip patch antenna that runs at 3.5 GHz—perfect for 5G wireless systems. The team built the antenna on an FR-4 substrate (dielectric constant ?r = 4.3, thickness 1.6 mm), mostly because it’s cheap and easy to work with. They used CST Microwave Studio to tweak the structure, making sure it matches impedance well and delivers steady radiation. The results look solid. The antenna hits a return loss (S11) of ?30.60 dB, a VSWR of 1.06, and offers a bandwidth of 0.145 GHz, which means it handles the 5G sub-6 GHz band without breaking a sweat. Directivity sits at 6.05 dBi, so it’s up for 5G, WLAN, and WiMAX tasks. With its straightforward shape, small size, and affordable materials, this design stands out as a real contender for next-gen wireless gear.

Introduction

The growing demand for high-speed, low-latency, and highly reliable wireless networks has driven the development of 5G communication systems. The sub-6 GHz spectrum—especially the 3.5 GHz band—has become a key candidate for 5G due to its balanced trade-off between coverage and capacity. Microstrip patch antennas (MSAs) are widely used in such applications because they are compact, lightweight, easy to fabricate, and compatible with PCB technologies. However, traditional MSAs face challenges such as narrow bandwidth, limited gain, and dielectric losses, especially when fabricated on low-cost substrates like FR-4.

To address these issues, various enhancement methods such as defected ground structures, slot loading, parasitic elements, metamaterials, and MIMO systems have been proposed, although many introduce complexity and higher cost. FR-4 remains attractive for cost-sensitive applications, and with proper optimization, it can still offer adequate performance for WLAN and 5G systems.

In this work, a rectangular microstrip patch antenna operating at 3.5 GHz is designed and simulated using CST Microwave Studio. The antenna uses an FR-4 substrate (εr = 4.3, thickness = 1.6 mm) and aims to achieve compact size, improved bandwidth, and stable radiation characteristics. The design process employs standard equations for determining patch dimensions, effective dielectric constant, resonant length, and substrate size. After computing initial theoretical values, slight adjustments were made through optimization.

Simulation results include return-loss plots, VSWR characteristics, and 3D far-field radiation patterns, demonstrating that the proposed antenna meets the performance needs of sub-6 GHz 5G communication systems.

Conclusion

This paper introduces a single patch antenna with a new geometric design, built for 5G use at 3.5 GHz. The team designed and tested both simulated and real micro-strip antennas, then lined them up against six main benchmarks: return loss (S11), VSWR, bandwidth, gain, half-power beam-width, and far-field radiation pattern. Out of the different shapes tested, the rectangular micro-strip antenna stood out. It delivered better bandwidth, higher gain, stronger directivity, and more efficient performance overall. These antennas fit right into modern communication systems—think cell phones, satellite links, even radar gear. In short, the antennas in this study, especially the rectangular one, work well for 5G, WLAN, and Wi-MAX.

References

[1] Gupta and R.K. Jha, “A survey of 5G network: architecture and emerging technologies,” IEEE Access, vol. 3, pp. 1206–1232, 2015. [2] M. Shafi et al., “5G: A tutorial overview of standards, trials, challenges, deployment, and practice,” IEEE JSAC, vol. 35, no. 6, pp. 1201–1221, 2017. [3] A. Ghosh et al., “5G evolution: A view on 5G cellular technology beyond 3GPP release 15,” IEEE Access, vol. 7, pp. 127639–127651, 2019. [4] S. Chen and J. Zhao, “The requirements, challenges, and technologies for 5G,” IEEE Commun. Mag., vol. 52, no. 5, pp. 36–43, 2014. [5] ITU-R M.2083-0, “IMT Vision for 2020 and beyond,” ITU, 2015. [6] T. Thomas et al., “A new look at LTE for 5G,” IEEE Commun. Mag., vol. 54, no. 12, pp. 38–47, 2016. [7] W. Roh et al., “Millimeter-wave beamforming for 5G cellular communications,” IEEE Commun. Mag., vol. 52, no. 2, pp. 106–113, 2014. [8] Y. Zhang et al., “Design of a low-profile 5G antenna for IoT devices,” Int. J. RF Microw. Comput.-Aided Eng., vol. 30, no. 7, 2020. [9] C.A. Balanis, Antenna Theory: Analysis and Design, Wiley, 2016. [10] R. Garg et al., Microstrip Antenna Design Handbook, Artech House, 2001. [11] K.L. Wong, Compact and Broadband Microstrip Antennas, Wiley, 2002. [12] D.M. Pozar, “Microstrip antennas,” Proc. IEEE, vol. 80, no. 1, pp. 79–91, 1992. [13] R. Chair et al., “Wideband multi-slot microstrip antenna,” IEEE TAP, vol. 52, no. 3, pp. 1084–1087, 2004. [14] H. Huang et al., “A compact broadband antenna for 5G,” IEEE AWPL, vol. 18, no. 5, pp. 977–981, 2019. [15] O. Darboe et al., “A 28 GHz rectangular patch antenna for 5G,” Int. J. Eng. Res. Tech., vol. 12, 2019. [16] M. Kumar, A. Basu, “Compact FR-4 based dual-band antenna,” AEU Int. J. Electron. Commun., vol. 70, no. 10, pp. 1407–1413, 2016. [17] S. Das, A. Chakraborty, “Performance of FR-4 microstrip patch at 2.4 GHz,” IET Microw. Antennas Propag., vol. 9, no. 15, pp. 1760–1766, 2015. [18] J. Lee, K. Sarabandi, “Design of compact FR-4 microstrip antennas,” IEEE TAP, vol. 53, no. 1, pp. 104–113, 2005. [19] J. Anguera et al., “Defected ground structures in microstrip technology,” IEEE AP Mag., vol. 57, no. 6, pp. 36–47, 2015. [20] R. Kumar, J. Kumar, “A compact DGS based microstrip antenna,” Microw. Opt. Tech. Lett., vol. 57, no. 7, pp. 1612–1616, 2015. [21] J. Hu et al., “Slot-loaded microstrip antenna for 5G,” PIER C, vol. 95, pp. 15–25, 2019. [22] N. Ojaroudi et al., “Small microstrip slot antenna design,” IEEE AWPL, vol. 8, pp. 652–655, 2009. [23] S. Zhu, R. Langley, “Dual-band wearable textile antenna,” IEEE TAP, vol. 57, no. 4, pp. 926–935, 2009. [24] N. Hussain et al., “Metasurface-based low-profile wideband antenna,” IEEE Access, vol. 8, pp. 19074–19083, 2020. [25] M. Ali, A.R. Sebak, “Dual-band CPW slot antenna,” IEEE APSURSI, 2016. [26] M.S. Sharawi, “Printed multi-band MIMO antennas,” IEEE AP Mag., vol. 55, no. 5, pp. 218–232, 2013. [27] P. Li et al., “Compact dual-band MIMO antenna for 5G,” IEEE Access, vol. 7, pp. 127168–127176, 2019. [28] T. Ali et al., “Compact four-element MIMO antenna for 5G smartphones,” IEEE AWPL, vol. 19, no. 12, pp. 2106–2110, 2020. [29] S. Bhunia et al., “On the design of FR-4 substrate antennas: challenges and solutions,” Microwave Review, vol. 23, no. 2, pp. 35–42, 2017. [30] A. Bhattacharya et al., “Simulation-driven design of patch antennas using CST,” Microw. Opt. Tech. Lett., vol. 60, no. 3, pp. 707–712, 2018. [31] H. Zhang et al., “Simulation and optimization of 5G antenna structures,” IEEE Access, vol. 7, pp. 56250–56258, 2019. [32] J. Singh et al., “Design and analysis of antennas for 5G NR,” IET Microw. Antennas Propag., vol. 14, no. 6, pp. 456–463, 2020. [33] Y. Hashan, O. Haraz, E. El-Sayed, “Dual-band 28/38 GHz MIMO PIFA,” IEEE APSURSI, 2016. [34] W. Ahmad, W.T. Khan, “Small form factor PIFA for 5G,” IEEE ICMIM, 2017.

Copyright

Copyright © 2025 Brahman Singh Bhalavi , Anurag Shrivastava , Ram Dulare Nirala. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.