Jul 2026· 2026 International Conference on Intelligent and Sustainable AI Systems (ICOSAAS)· pp. 72-76· 0 citations· 15 references
Abstract
Compact 28/38 GHz mmWave antennas enable high-performance 5G MIMO communications. This paper presents the design and optimization of 28/38 GHz millimeter-wave (mmWave) antennas for high-performance 5G applications. The proposed antennas utilize patch and MIMO array configurations on low-loss substrates like Rogers RT5880 to deliver high gain and efficient radiation patterns. Defected Ground Structures (DGS) and parasitic elements enhance gain (> 7 dBi), minimize mutual coupling, and achieve an Envelope Correlation Coefficient (ECC) < 0.005, ideal for MIMO systems. Validation via CST Studio Suite simulations confirms return losses below −10 dB, radiation efficiency exceeding 80%, and excellent isolation in arrays. These antennas address path loss and atmospheric absorption in 5G mmWave networks, enabling ultra-high data rates for mobile devices, IoT, and next-generation wireless systems. The framework supports extensions to multi-band operation, beam-steering, and scalable MIMO configurations with sustained efficiency and low element correlation.
This paper presents a compact dual-band circularly polarized two-port MIMO antenna for millimeter-wave applications at 28 and 38 GHz. The single-element antenna occupies an ultra-small area of 8 mm × 16 mm and is fabricated on a Rogers RO3003 substrate (εr = 3, thickness = 0.25 mm). Circular polarization is achieved at both bands, with measured axial ratios of 1.4 dB at 28 GHz and 2.2 dB at 38 GHz, providing robustness against polarization mismatch. The antenna achieves peak realized gains of 7.5 dBi and 5.5 dBi at 28 GHz and 38 GHz, respectively. Experimental results show good impedance matching and radiation patterns in close agreement with simulations. Based on the validated single-element design, a two-port MIMO configuration is implemented, where one element generates RHCP and the other LHCP, enabling polarization diversity. The MIMO antenna exhibits low envelope correlation coefficient and high diversity gain. Owing to its compact size, dual-band circular polarization, and effective polarization-diverse MIMO performance, the proposed antenna is suitable for space-constrained 5G and future millimeter-wave wireless devices.
A. Farahat, K. Hussein· Scientific Reports· 0 citations
A four-element multiple-input multiple-out (MIMO) antenna employing a metamaterial (MMT)-based structure is presented for sub-6 GHz wireless applications. The antenna is fabricated on an FR4 substrate and operates over the 5.7–5.9 GHz band, centred at 5.8 GHz. The overall antenna size is 46 × 44 × 1.6 mm3 (0.89λ0 × 0.85λ0 × 0.03λ0 at 5.8 GHz). Inherent decoupling is achieved through the orthogonal placement of the antenna elements, while the integrated MMT structure further suppresses mutual coupling and enhances radiation efficiency. Both simulated and measured results show good agreement, confirming reliable antenna performance across the intended frequency range. The proposed design achieves a maximum gain of 4.4 dBi, with isolation better than 24.5 dB. MIMO diversity characteristics are evaluated using envelop correlation coefficient (ECC), diversity gain (DG), Total active reflection coefficient, and channel capacity loss (CCL), an ECC below 0.001, a DG close to 10 dB, and a CCL below 0.5 bits s−1 Hz−1. User safety is assessed through specific absorption rate (SAR) analysis using a female hand phantom at 17 mW input power, demonstrating a reduction in SAR from 1.493 W kg−1 to 1.295 W kg−1 with the MTM, suitable for handheld devices.
R. Julia Karal Adisaya, D. David, M. Nesasudha· Engineering Research Express· 0 citations
Millimeter-wave communication has become a cornerstone of emerging 5G and future 6G systems due to its ability to support multi-gigabit data rates, ultra-low latency, and dense device connectivity. These performance requirements enforced constraints that are not limited to antenna size, bandwidth, polarization, and multiple-input-multiple-output (MIMO) configuration. Addressing these challenges, this work proposes a compact circularly polarized antenna optimized for broadband operation around the 28-GHz band. The design employs simple yet effective techniques, utilizing a ring-shaped radiator excited through a via-fed central patch which enables strong impedance matching and stable circular polarization. A three-stage geometric evolution is adopted to achieve enhanced bandwidth and improved return loss, where the introduction of an annular slot and arc-shaped perturbation plays a key role in generating the required CP mode. The final single-element achieves impedance bandwidth of 25.5–30.55 GHz, with an axial-ratio bandwidth ranges 26.4–28.4 GHz. An equivalent circuit model is developed using ADS, where the simulated results closely match the electromagnetic response obtained for the CST. To enhance spatial diversity and satisfy mm-wave MIMO requirements, the design is extended onto four-port self-decoupled configuration. The MIMO array maintains high isolation across the operational bandwidth without relying on additional parasitic decoupling elements. A comparison with recent literature verifies the compact size of antenna in standalone and MIMO configurations, along with high performance parameters in both cases. These results demonstrate the suitability of the antenna for compact 28-GHz terminals, present, and future 5G/6G wireless devices.
A. Althuwayb, Sangmin Lee, E. M. Ali et al.· Scientific Reports· 0 citations
A compact dual-band Multiple-Input Multiple-Output (MIMO) antenna array comprising eight elements is reported for deployment in 5G handheld terminals. The array simultaneously addresses the n78 band (3.4-3.8 GHz) and the n258 millimeter-wave band (24.5–27.5 GHz), realizing both operating ranges within a single-layer substrate whose overall dimensions are compatible with contemporary smartphone form factors. Each radiating element combines a T-shaped primary branch with two asymmetric C-shaped resonators, a topology that produces independent resonances at the two target bands. Interelement isolation is enhanced through the joint action of defected ground structures (DGS) and a passive neutralization line (NL), which together raise the minimum isolation from approximately 11 dB to 18 dB across the full bandwidth. Cross-validation by CST Microwave Studio and ANSYS HFSS confirms realized gains of 5.7 dBi at 3.6 GHz and 6.4 dBi at 26 GHz, total radiation efficiency in the 85–94 % range, and envelope correlation coefficients (ECC) below 0.04—all confirming suitability for spatial-multiplexing operation in next-generation mobile devices.
Adnane Ghiat, Jesús R. Pérez, A. Tribak et al.· EPJ Web of Conferences· 0 citations
The rapid evolution of fifth-generation (5G) and emerging sixth-generation (6G) wireless communication systems has considerably intensified the need for high data rates, ultra-low latency, massive connectivity, and intelligent network integration. To satisfy these requirements, millimeter-wave (mmWave) bands offer large available bandwidths; however, their severe propagation losses and integration constraints necessitate advanced antenna solutions. In this context, compact multi-port Multiple-Input–Multiple-Output (MIMO) antennas are a key solution for high-capacity and reliable mmWave communications. This review presents a comprehensive overview of recent antenna system technologies for 5G/6G applications, focusing on small mmWave MIMO antenna designs, performance improvement methods, advanced materials, and smart integration methods. Several antenna structures, such as microstrip patch, dielectric resonator, slot-based, and metamaterial-inspired designs, are critically discussed and compared. In addition, this review analyzes key design challenges involving miniaturization, mutual coupling reduction, bandwidth enhancement, gain improvement, radiation efficiency, and integration complexity, along with their impact on key performance metrics. The importance of advanced materials, artificial-intelligence-assisted optimization, hybrid antenna architectures, and smart integration strategies in future 5G/6G systems is also emphasized. Finally, we identified current challenges, emerging trends, and future research directions to provide useful design guidelines for researchers and engineers developing next-generation high-performance antenna systems for intelligent wireless communications.
This paper introduces a compact ultra-wideband MIMO antenna featuring an integrated notch-band response. Wideband operation is achieved through the combined use of meandered feed lines, a modified Y-shaped radiating element, and a defected ground structure. The antenna occupies a compact volume of 12 x 8 x 1.6 mm³ and operates over the 30–42.5 GHz frequency range, while notch band from 35 to 38.5 GHz is effectively suppressed using a split-ring resonator positioned parallel to the feed line. Implemented on an RT/Duroid 5880 substrate, the antenna delivers a peak realized gain of 6.51 dB and maintains radiation efficiency above 88%. High inter-element isolation exceeding 22 dB is obtained through a dedicated decoupling structure. Moreover, the proposed MIMO system demonstrates strong diversity performance, with envelope correlation coefficient below 0.02, diversity gain greater than 9.97 dB. These characteristics confirm the suitability of the proposed antenna for compact 5G, satellite, and millimeter-wave communication platforms.
Janardhana Reddy Pandillapalli, Kameswari Gummadi· International Journal of Ele...· 0 citations
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