Sep 2026· IEEE Journal on Miniaturization for Air and Space Systems· Vol 7, pp. 365-378· 0 citations· 44 references
Abstract
Metalens antennas are emerging as promising candidates for compact high-gain antenna systems in next-generation wireless and satellite communication applications, where stringent link-budget requirements demand highly directive yet lightweight and compact apertures. In such systems, improving aperture efficiency is critical because it reduces the physical aperture size required to achieve a target gain, thereby enabling antenna miniaturization. Although recent studies have explored generative artificial intelligence (AI) techniques for unit-cell optimization, realizing compact and efficient metalens antennas requires a broader metalens-system-level design approach. In this work, a modular, scalable, dual-linearly polarized metalens antenna is proposed through a systematic investigation of the key parameters governing aperture efficiency, thereby enhancing overall antenna compactness. Unlike prior works primarily focused on unit-cell optimization, the proposed approach jointly optimizes both the feed antenna and the metalens structure to achieve efficient aperture illumination and reduced effective aperture requirements. In particular, the study investigates: 1) unit-cell topology; 2) amplitude thresholding; 3) number of metal layers; 4) interlayer pattern variation; 5) unit-cell dimensions; and 6) spatial placement of unit cells based on feed characteristics. This holistic optimization significantly improves aperture efficiency, enabling high-gain performance with a comparatively smaller aperture. To support practical deployment, a modular architecture based on standard printed circuit board (PCB) panels is introduced, enabling scalable and low-cost fabrication with precise alignment achieved using 3-D-printed fixtures. The proposed design is experimentally validated using a $0.7\times 0.7$ m X-band prototype, achieving a maximum measured gain of 36.3 dBi and a high aperture efficiency of 60.2%. These results demonstrate the potential of the proposed approach for compact, high-gain, and cost-effective satellite communication ground-station systems.
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.
Mahesha S, Sushma N, D. C et al.· 2026 International Conferenc...· 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.
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.
Conventional FR4 substrates have high frequency problems, with polarization capability and performance deterioration being major challenges in its design. To overcome these limitations, this article describes a multi-step notched antenna that is combined with a star-shaped Frequency Selective Surface (FSS) in order to demonstrate better electromagnetic performance at a higher frequency. Although FR4 exhibits higher dielectric loss at X-band frequencies, it was selected for its low cost, easy fabrication, and practical prototyping advantages. The standalone FR4-based antenna achieves a gain of 3.77 dBi, while the integration of the star-patterned FSS improves the gain to 7.31 dBi by enhancing broadside field reinforcement and reducing backward radiation. Therefore, the reported gain improvement is attributed to the FSS-assisted radiation enhancement rather than the FR4 substrate alone. The proposed antenna resonates at 9.8 GHz and has a reflection coefficient of -38.4dB with an attained gain of 3.77dB. In order to improve the antenna performance even more, unit cell FSS is used in form of a star shape and its dimensions measure 1.44λ0 × 1.44λ0 × 1.6 mm3. The FSS integration leads to a high degree of improvement such as improved impedance matching, broader angular stability of circular polarization in both principal planes as well as an achieved increase of gain as high as 7.3dB. These findings present the demonstration that the multi-step notch antenna with the FSS integration provides a good solution to X-band applications. Hence, the proposed FSS assisted multi-step notched antenna is mainly designed for compact X-band applications like short-range radar sensing, defence surveillance communication, satellite communication front-end modules, and high gain directional wireless links that demand high gain, impedance matching, radiation efficiency and circular polarization stability.
M. Saranya, R. Gayathri· Scientific Reports· 0 citations
A new method, called CW-Net, translates the reasoning process of an autonomous vehicle’s AI system into understandable concepts that explain its behavior.