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Review

Recent Advancements in Millimeter-Wave Antennas and Arrays: From Compact Wearable Designs to Beam-Steering Technologies

by
Faisal Mehmood
1 and
Asif Mehmood
2,*
1
Department of AI and Software, College of IT Convergence, Gachon University, Seongnam-si 13120, Republic of Korea
2
Department of Biomedical Engineering, College of IT Convergence, Gachon University, Seongnam-si 13120, Republic of Korea
*
Author to whom correspondence should be addressed.
Electronics 2025, 14(13), 2705; https://doi.org/10.3390/electronics14132705
Submission received: 15 May 2025 / Revised: 2 July 2025 / Accepted: 2 July 2025 / Published: 4 July 2025
(This article belongs to the Special Issue Recent Advancements of Millimeter-Wave Antennas and Antenna Arrays)
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Abstract

Millimeter-wave (mmWave) antennas and antenna arrays have gained significant attention due to their pivotal role in emerging wireless communication, sensing, and imaging technologies. With the rapid deployment of 5G and the transition toward 6G networks, the demand for compact, high-gain, and reconfigurable mmWave antennas has intensified. This article highlights recent advancements in mmWave antenna technologies, including hybrid beamforming using phased arrays, dynamic beam-steering enabled by liquid crystal and MEMS-based structures, and high-capacity MIMO architectures. We also examine the integration of metamaterials and metasurfaces for miniaturization and gain enhancement. Applications covered include wearable antennas with low-SAR textile substrates, conformal antennas for UAV-based mmWave relays, and high-resolution radar arrays for autonomous vehicles. The study further analyzes innovative fabrication methods such as inkjet and aerosol jet printing, micromachining, and laser direct structuring, along with advanced materials like Kapton, PDMS, and graphene. Numerical modeling techniques such as full-wave EM simulation and machine learning-based optimization are discussed alongside experimental validation approaches. Beyond communications, we assess mmWave systems for biomedical imaging, security screening, and industrial sensing. Key challenges addressed include efficiency degradation at high frequencies, interference mitigation in dense environments, and system-level integration. Finally, future directions, including AI-driven design automation, intelligent reconfigurable surfaces, and integration with quantum and terahertz technologies, are outlined. This comprehensive synthesis aims to serve as a valuable reference for advancing next-generation mmWave antenna systems.

1. Introduction

Millimeter-wave (mmWave) antennas and arrays have become a cornerstone of modern communication and sensing technologies. The rapid development of 5G networks and the anticipated transition to 6G demand highly efficient, compact, and adaptive mmWave antenna systems. These antennas enable high-speed data transmission, low-latency communication, and improved spectral efficiency. Additionally, their applications extend beyond wireless communication to include imaging, sensing, and UAV-based connectivity.

1.1. Background and Significance

The increasing demand for high-data-rate wireless communication has necessitated the exploration of higher frequency bands, particularly in the mmWave spectrum [1]. Unlike sub-6 GHz frequencies, which are congested and prone to interference, mmWave bands offer substantial bandwidth, making them ideal for next-generation networks. However, designing efficient antennas at these frequencies presents unique challenges due to higher propagation losses, atmospheric absorption, and complex fabrication requirements.
The evolution from 5G to 6G is expected to revolutionize communication networks, enabling ultra-reliable low-latency communication (URLLC), enhanced mobile broadband (eMBB), and massive machine-type communication (mMTC) [2]. The integration of mmWave antennas in various applications, such as smart cities, autonomous vehicles, and industrial IoT, highlights their growing importance. mmWave technologies play a critical role in radar, remote sensing, and imaging applications, which further expands their potential impact.

1.2. Evolution of mmWave Antennas and Arrays

Historically, mmWave frequencies were primarily utilized in military and aerospace applications due to their precision and high-resolution capabilities. However, advancements in semiconductor technology, materials science, and computational electromagnetics have enabled the widespread adoption of mmWave antennas in commercial and consumer applications [3]. The miniaturization of components and the development of highly efficient beamforming techniques have made mmWave antennas more practical for integration into handheld devices, wearables, and automotive systems [4].

1.3. Challenges in mmWave Antenna Design

Despite their numerous advantages, mmWave antennas face several design and implementation challenges [5,6]:
  • High signal loss: mmWave signals become weak due to air, obstacles, and absorption.
  • Weak penetration: they have limited penetration through obstacles such as walls, foliage, and the human body.
  • Miniaturization: designing efficient antennas for compact devices is challenging.
  • Heat issues: high frequencies can cause heating.
  • Material limits: regular materials do not work well; new ones are needed.

1.4. Applications of mmWave Antennas

mmWave antennas are being used in different industries other than telecommunications, which include healthcare, defense, and automotive technology:
  • 5G and 6G networks: mmWave technology enables high-speed wireless communication, offering faster data transfer, reduced latency, and better efficiency [7].
  • Wearable and body-centric antennas: compact and flexible mmWave antennas support advancements in wearable electronics, smart textiles, and health monitoring devices [8].
  • Autonomous vehicles and UAV communication: mmWave antennas are crucial for vehicle-to-everything (V2X) communication, allowing real-time data exchange for navigation and collision avoidance [9].
  • Radar and remote sensing: mmWave radar systems are used for precise object detection and environmental sensing in defense, weather monitoring, and industrial applications [10].
  • Biomedical imaging and security screening: mmWave imaging technologies are used in medical diagnostics [11], security, and non-invasive scanning [12].
This review provides a deep look at recent advancements in mmWave antenna design, covering topics like beamforming, MIMO systems, metamaterials, and wearable applications. It also highlights the latest developments in fabrication techniques, numerical modeling, and experimental validation. This paper discusses challenges in optimizing efficiency and integrating AI with antenna design. This work aims to be a valuable resource for researchers, engineers, and professionals in the field of mmWave antenna technology.
The remainder of this paper is structured as follows: Section 2 provides methodology and the fundamental background of millimeter-wave antennas and outlines the core challenges associated with their implementation at high frequencies. Section 3 discusses antenna design and optimization techniques, including beamforming, MIMO architectures, and wearable antenna systems. Section 4 explores advancements in materials, fabrication methods, and integration technologies that enable compact, high-performance antenna designs. In Section 5, key application areas are presented, ranging from 5G/6G communications to radar, imaging, UAVs, and body-centric systems. Section 6 offers a discussion on current limitations, future research directions, and emerging innovations such as AI-driven optimization and quantum communication integration. Finally, Section 7 concludes the paper by summarizing the major developments and highlighting the ongoing evolution and potential of mmWave antenna technologies.

2. Methodology

In this review, we take a systematic approach for a comprehensive and unbiased selection of the relevant work on recent advancements in millimeter-wave antennas and arrays. We have followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines in this review paper. We used IEEE Xplore, Scopus, and Web of Science databases for conducting a literature search. The search covered studies between 2000 and 2025. Keywords like ’mmWave antennas’, ’beam-steering arrays’, ’MIMO’, and ’wearable antennas’ were used in academic databases. In this review, we used Mendeley for managing references and organizing research.

2.1. Databases Searched

The choice of databases is important for a thorough literature review. For this review, we selected the following databases because they cover a wide range of peer-reviewed research in electrical engineering, wireless communication, and antenna technologies.

2.1.1. IEEE Xplore

IEEE Xplore is a leading source for research in electrical engineering and communication systems. It offers a wide range of journal articles, conference papers, and standards related to mmWave antennas, phased arrays, and 5G/6G technologies.

2.1.2. Scopus

Scopus is a large database that covers a wide range of topics, including engineering, physics, and materials science. It is especially useful for finding research on mmWave devices, array design, beamforming, and related communication technologies. Its citation tools are great for tracking the impact of important publications in the field.

2.1.3. Web of Science

Web of Science (WoS) indexes top journals across various scientific fields. It is a helpful resource for finding influential papers on antenna design, high-frequency circuits, and mmWave propagation modeling. Its citation tools are also useful for tracking research trends and top authors in the mmWave field.

2.2. Search Strategy and Keywords

In this review, we used a structured search strategy with a combination of controlled vocabulary and free-text keywords to find relevant work in the domain of mmWave antennas and arrays.

Keyword Selection

We used common words used in mmWave antenna research, wireless communication systems, and related technologies. The primary search term included the following:
  • mmWave antennas;
  • Phased array antennas;
  • Millimeter wave communication;
  • Beamforming techniques;
  • 5G and 6G antenna design;
  • High-frequency antenna arrays.
To ensure a comprehensive and flexible search, Boolean operators were applied to combine and expand search queries:
  • AND (e.g., mmWave AND phased arrays) to narrow results by combining related topics.
  • OR (e.g., millimeter wave OR mmWave) to include different terms and synonyms.
This approach enabled us to retrieve a wide spectrum of relevant literature across different aspects of mmWave technology, including design, simulation, fabrication, and application in modern wireless systems.

2.3. Inclusion and Exclusion Criteria

The articles reviewed in this paper were chosen based on clear criteria to ensure they are relevant, high-quality, and technically significant. The selection emphasized recent advancements in mmWave antenna design, phased arrays, and related technologies for next-generation wireless communication. The inclusion criteria were as follows:
  • Peer-reviewed journal articles or conference papers.
  • Studies published between 2000 and 2025.
  • Articles focused on the design, analysis, fabrication, or application of mmWave antennas, phased arrays, or beamforming techniques.
  • Papers that address performance evaluation, challenges, or future trends in mmWave communication and antenna systems.
The following exclusion criteria were applied to filter out less relevant or lower-quality sources:
  • Non-English articles.
  • Editorials, opinion, and non-peer-reviewed papers.
  • Studies that focus only on theoretical models without experimental validation.
  • Duplicate studies or articles lacking full-text access.

2.4. Data Extraction and Analysis

After identifying relevant studies through the systematic search, data extraction and analysis were conducted to organize the findings. The process included the following steps:
  • Study details: Author(s), publication year, and source (journal/conference).
  • Objective: The aim and scope of the study.
  • Methodology: Study design and experimental setup.
  • Findings: Major contributions and results.
  • Discussion: Gaps identified in the study.
Figure 1 illustrates the systematic process used to select relevant studies for this comprehensive review. An initial total of 325 records was retrieved from IEEE Xplore, Scopus, and Web of Science databases. Prior to the screening stage, 80 records were removed due to duplication (30 records), automated filtering (25 records), and other reasons such as incomplete metadata or irrelevant scope (25 records). The remaining 245 records underwent title and abstract screening, during which 90 were excluded based on relevance, technical depth, or non-English content. The 155 full-text articles were then assessed for eligibility; however, 62 of them could not be accessed due to institutional restrictions, broken links, or missing full texts. Ultimately, 91 studies were included in the final literature review. Among these, 33 were selected for detailed analysis based on their technical significance, novelty, and alignment with the scope of this review. Table 1 summarizes the key features of these selected mmWave antenna research works.

3. Antenna Design and Optimization Techniques

Millimeter-wave antenna design and optimization represent a dynamic and challenging field, driven by the need for compact, high-performance systems capable of supporting high-speed communication and sensing applications. This section explores three key areas of innovation: beamforming and beam-steering techniques, MIMO antenna architectures, and the development of compact and wearable antenna systems.

3.1. Beamforming and Beam-Steering Techniques

Beamforming is a signal processing technique used in antenna arrays to direct the transmission or reception of signals in specific directions. In mmWave frequencies, beamforming compensates for high path loss and provides enhanced directivity [46]. There are three primary categories of beamforming: analog, digital, and hybrid. Analog beamforming utilizes phase shifters at the RF front-end to adjust the phase of signals fed into antenna elements, offering simplicity and power efficiency but limited flexibility. Digital beamforming performs processing at the baseband level, enabling multiple beams and supporting MIMO operation, although it increases cost and power consumption. Table 2 presents the comparative analysis of beamforming techniques in mmWave systems.

3.2. MIMO Antennas and Array Architectures

MIMO (Multiple-Input, Multiple-Output) antenna systems improve communication by sending and receiving multiple data streams at the same time. In mmWave systems, MIMO helps reduce signal loss and blockage by using spatial diversity and increasing spectral efficiency [50]. Common MIMO array types include planar, cylindrical, and massive MIMO arrays. Planar arrays, made of flat grids of antenna elements, are popular in base stations and portable devices because they are simple and compact. Cylindrical and spherical arrays offer full 360-degree coverage, which is useful for mobile platforms like UAVs. Massive MIMO uses hundreds of antennas to provide better beam control and reduce interference, which is important for 5G and 6G networks [51]. Table 3 presents the performance-oriented comparison of MIMO array structures.
  • Planar Arrays: Most common in mmWave applications due to compactness and ease of fabrication.
  • Cylindrical and Spherical Arrays: Provide 360° coverage and are often used in mobile or drone-based platforms.
  • Massive MIMO: Employs large-scale arrays with hundreds of elements to improve beamforming granularity and reduce interference.

3.3. Compact and Wearable Antennas

As mobile and wearable devices continue to decrease in size, the demand for miniaturized millimeter-wave antennas correspondingly increases. Wearable antennas also need to fit the shape of the human body and use skin-friendly materials. The rise in demand for wearables and compact communication devices has pushed the development of small mmWave antennas [55]. Designing these antennas is challenging because they must perform well even in tight spaces and on curved surfaces. Flexible substrates such as PDMS, Kapton, and Rogers are commonly employed to ensure that antennas can undergo bending and stretching with negligible impact on their performance. Another new approach is using e-textiles—fabrics with conductive fibers—to build antennas directly into clothing for wearable use:
  • Flexible substrates: use of polymers like PDMS, Kapton, and Rogers materials for stretchability and bendability [56].
  • E-textiles: integration of conductive threads into clothing to form body-worn antenna arrays [57].
  • Fractal geometries: space-filling curves that provide multiband operation in a compact footprint [58].
  • Implantable antennas: developed for biomedical telemetry at mmWave frequencies [59].
Advancements in design have enhanced the flexibility and durability of wearable antennas. The use of materials such as Kapton and PDMS enables antennas to bend and stretch while maintaining minimal performance degradation. E-textiles make it possible to build antennas directly into clothing while keeping them comfortable to wear. Fractal designs help antennas work across multiple frequency bands in a small space. There is also progress in developing implantable antennas for medical use, allowing reliable wireless communication in health monitoring systems [60].
Even with these advances, some challenges remain. It is still difficult to keep performance stable when the antenna is bent, reduce the amount of radiation absorbed by the body (SAR), and ensure the antennas are strong enough for daily use. Solving these problems requires new materials, smart designs, and teamwork across fields like electronics, materials science, and biomedical engineering.
A 60 GHz rectangular patch antenna fabricated on a flexible 0.05 mm Kapton (polyimide) substrate demonstrated a peak gain of approximately 5 dBi at 60.3 GHz, along with stable return loss and radiation characteristics under slight bending conditions. These results highlight the suitability of Kapton substrates for conformal and wearable millimeter-wave antenna applications [61].
To support multiband operation in small spaces, fractal and self-similar structures are often used. Implantable mmWave antennas are also being explored for real-time health tracking and brain–computer interfaces. These antennas must be safe to use inside the body and perform well in biological conditions, following safety standards.
Maintaining consistent impedance matching under deformation, minimizing specific absorption rate (SAR) to ensure safety, and ensuring durability under repeated use are critical design constraints. Emerging applications of wearable mmWave antennas include augmented and virtual reality headsets, medical diagnostics, military gear, and IoT-enabled smart clothing [62].

4. Materials, Fabrication, and Integration Technologies

The advancement of mmWave antenna systems has been closely tied to innovations in materials, fabrication methods, and integration techniques. These elements play a crucial role in achieving high-performance, cost-effective, and reliable antenna solutions suitable for a wide range of applications.

4.1. Advanced Materials for mmWave Antennas

Material selection is a key determinant of antenna performance, particularly at millimeter-wave frequencies where signal losses and dielectric behavior become more critical. Traditional substrates such as FR4, with a dielectric constant ( ε r ) of 4.4 and a dissipation factor (tan δ ) of 0.02, are unsuitable due to excessive losses at mmWave bands. In contrast, low-loss dielectric materials like Rogers RO3003 ( ε r ≈ 3.0 , tan δ ≈ 0.001 ), RO4350B ( ε r ≈ 3.48 , tan δ ≈ 0.0037 ), and Taconic TLY-5 ( ε r ≈ 2.2 , tan δ ≈ 0.0009 ) are widely adopted for their stable electrical properties and minimal signal attenuation [63].
For wearable and flexible antennas, materials such as PDMS, polyimide (Kapton), and textile composites offer mechanical flexibility while maintaining acceptable dielectric properties. For instance, Kapton exhibits a dielectric constant of around 3.4 and supports stable operation near 60 GHz with minimal performance degradation under bending [61]. Conductive materials, including copper foils, silver nanoparticle inks, and graphene-based composites, are used for radiating elements, with graphene offering additional benefits like transparency and stretchability.
The emergence of engineered materials such as metamaterials and metasurfaces has enabled advanced functionalities like antenna miniaturization, wideband operation, and beam shaping. These materials exhibit custom-tailored effective permittivity and permeability values, enabling superior control over electromagnetic wave propagation.
Recent developments in tunable and reconfigurable materials have facilitated dynamic antenna performance control. Liquid crystals (LCs), ferroelectrics, and phase-change materials can adjust their dielectric constants in response to external stimuli such as voltage or temperature. For example, beam-steerable patch arrays using LCs have demonstrated scanning capabilities in the 60 GHz band with tuning ranges of ε r from 2.5 to 3.0 under modest bias voltages [64]. Such implementations enable reconfigurable beamforming and adaptive communication in compact devices.

4.2. Fabrication Techniques and Challenges

Modern fabrication methods are evolving rapidly to meet the complex demands of mmWave antenna miniaturization, structural conformity, and cost-efficiency. Conventional printed circuit board (PCB) etching remains the standard for fabricating planar antennas due to its widespread availability, moderate cost, and compatibility with standard RF substrates. However, the limitations of PCB processes—particularly when fabricating conformal, multilayer, or sub-wavelength structures—have driven research toward more advanced and scalable alternatives [65].
Additive manufacturing (AM), particularly 3D printing techniques such as inkjet and aerosol jet printing, has emerged as a promising approach for fabricating low-cost, conformal mmWave antennas. At 28 GHz and 60 GHz, printed antennas on flexible substrates like Kapton have achieved measured gains in the range of 6–8 dBi, with radiation efficiencies exceeding 70%, demonstrating mechanical flexibility suitable for wearable and body-centric applications [66,67].
Scalability is another key concern. While inkjet printing is suitable for small-batch prototyping, its throughput is limited for mass manufacturing. Efforts to improve scalability involve adapting roll-to-roll (R2R) processing and integrating in-line sintering methods, but this adds complexity and cost. Moreover, achieving uniform ink deposition on non-planar surfaces remains difficult, impacting impedance consistency at mmWave frequencies.
Laser direct structuring (LDS) has also been utilized for integrating mmWave antennas into complex 3D surfaces, particularly in automotive systems. LDS-fabricated antennas operating around 24 GHz have shown stable gain values of approximately 7 dBi and efficiency above 70%, making them viable for embedding within curved panels or vehicular enclosures [68]. However, the dependence on laser-activated materials and the cost of specialized equipment currently limit widespread adoption in consumer markets.
Micromachining and photolithography, commonly used in MEMS fabrication, remain essential for achieving sub-100 μm feature sizes with tight dimensional control. These methods support high-performance antennas with low surface roughness and minimal losses, ideal for integration with MMICs in radar and THz communication systems [69]. However, the high costs, cleanroom requirements, and limited mechanical flexibility restrict their use to niche applications.
Future research must address trade-offs between fabrication resolution, cost-effectiveness, mechanical robustness, and environmental durability. For example, hybrid techniques that combine 3D printing with selective plating or laser sintering may offer a path toward scalable and cost-efficient fabrication of multilayer or reconfigurable antennas. Additionally, the development of printable, stretchable conductors with high conductivity and environmental stability is critical to realizing next-generation flexible mmWave devices.
While these fabrication techniques offer promising performance, challenges remain regarding long-term mechanical durability and scalability. Ongoing research focuses on hybrid methods and advanced conductive inks to improve environmental stability and manufacturability. Table 4 presents a comparison of advanced fabrication techniques for mmWave antennas.

4.3. Integration with Devices and Systems

Effective integration of antennas into complete systems is vital to realize compact, multifunctional mmWave solutions. System-level integration involves co-designing antennas with transceivers, power supplies, and enclosures to minimize interference, improve efficiency, and reduce overall size [70].
System-in-package (SiP) and antenna-in-package (AiP) technologies are increasingly used to embed antennas within semiconductor packages. These approaches reduce interconnect losses, enhance performance, and allow for high levels of miniaturization suitable for 5G/6G user equipment. Co-integration with MMICs and SDRs enables dynamic adaptation of antenna parameters to real-time communication requirements.
For wearable applications, integration challenges include ensuring flexibility, washability, and low-profile construction. Techniques such as screen printing on textiles, embroidering conductive yarns, and encapsulating antennas in protective layers have been developed to address these issues. For example, screen-printed antennas on cotton substrates have achieved return losses below –15 dB and efficiency above 60% at 28 GHz, while maintaining flexibility and washability.
In automotive and UAV systems, the integration of conformal antennas onto vehicle surfaces, windows, or drone bodies allows aesthetic and aerodynamic benefits while supporting advanced communication and sensing functions. Transparent antennas embedded on windshield glass using conductive oxides are also being explored for vehicular applications.
Overall, the synergy between novel materials, advanced fabrication techniques, and thoughtful integration strategies continues to drive the evolution of mmWave antenna technology, enabling smarter, smaller, and more capable systems for a wide range of next-generation applications [71].

4.4. Performance Evaluation Metrics

The performance of mmWave antennas is typically assessed using several key metrics to ensure suitability for target applications. These include the following:
  • Return loss (S11): Measures the amount of power reflected back from the antenna input. A lower return loss (e.g., less than −10 dB) indicates better impedance matching and efficient power transfer.
  • Gain: Represents the antenna’s ability to direct radiated power in a specific direction, typically expressed in decibels relative to an isotropic radiator (dBi). Higher-gain antennas provide improved signal strength and range.
  • Radiation efficiency: The ratio of power radiated by the antenna to the power supplied to it. High efficiency minimizes losses due to materials and fabrication.
  • Bandwidth: the frequency range over which the antenna maintains acceptable performance, often defined by return loss or gain criteria.
  • Isolation (for MIMO systems): describes the degree of decoupling between antenna elements, critical for reducing mutual interference and improving system capacity.
  • Specific absorption rate (SAR): important for wearable antennas, SAR quantifies the rate at which human tissue absorbs electromagnetic energy, necessitating designs that minimize exposure.
  • Beamforming accuracy: for phased arrays and beam-steering antennas, the precision of beam direction and shape affects system performance in dynamic environments.
These metrics are typically derived from a combination of simulated and measured data, providing a comprehensive evaluation of antenna performance in realistic operating conditions.

5. Applications of mmWave Antennas

Millimeter-wave (mmWave) antennas have found widespread application across numerous high-frequency domains due to their ability to support ultra-high data rates, miniaturized form factors, and precise beam steering. This section explores the prominent application areas, including wireless communication, wearable electronics, automotive systems, unmanned aerial vehicles (UAVs), imaging, and sensing technologies. Each application imposes distinct performance requirements such as gain, polarization, beamwidth, and integration constraints.

5.1. Wireless Communication (5G and 6G Networks)

The deployment of mmWave antennas in 5G and upcoming 6G networks has revolutionized mobile broadband, enabling massive data throughput, ultra-low latency, and support for massive device connectivity. mmWave frequencies offer wider bandwidths compared with sub-6 GHz bands, allowing faster data rates [72]. Antennas in these systems often require high directional gain (10–20 dBi) and support for dual or circular polarization to improve link reliability in multipath-rich urban environments. Beamforming and massive MIMO are used to combat high path loss and blockage, making these antennas suitable for dense urban environments, small cells, and indoor systems. Table 5 presents the key benefits of mmWave antennas in wireless communication.

5.2. Wearable and Body-Centric Applications

Wearable mmWave antennas are increasingly employed in personal healthcare monitoring, smart textiles, AR/VR systems, and on-body communication networks. These antennas are designed to be flexible, stretchable, and lightweight, often integrated into garments, helmets, or wristbands. Table 6 presents applications of mmWave antennas in wearables.
Recent experimental demonstrations have validated the feasibility of mmWave antennas in AR/VR contexts. For instance, a 60 GHz flexible on-helmet patch antenna was fabricated and tested, showing stable gain and radiation patterns under bending and user movement, indicating its suitability for immersive applications [73]. Likewise, a conformal 28 GHz antenna array embedded in smart textiles for body-area networks was experimentally evaluated, with measured data confirming reliable performance during human motion [74]. These prototypes support high-data-rate wireless links essential for enabling low-latency AR/VR interactions.
Key design challenges include maintaining sufficient radiation efficiency and pattern stability under body-induced detuning. Polarization diversity and omnidirectional or broad-beam radiation patterns are often preferred to support dynamic movement. Furthermore, specific absorption rate (SAR) constraints require low-profile configurations and careful electromagnetic isolation to reduce antenna–body coupling and ensure user safety.
In addition to these technical challenges, interdisciplinary considerations such as biocompatibility, textile integration, and sustainability play a crucial role in the practical deployment of wearable mmWave antennas. Materials must be non-toxic, hypoallergenic, and comfortable for prolonged skin contact. Textile integration demands flexible and washable antenna structures capable of withstanding repeated mechanical deformation and environmental exposure [75]. Moreover, sustainability concerns drive research towards eco-friendly, recyclable, or biodegradable substrates and conductive inks, aiming to minimize environmental impact throughout the antenna lifecycle [76].
Table 6. Applications of mmWave antennas in wearables.
Table 6. Applications of mmWave antennas in wearables.
ApplicationFunction
Smart health monitoring [77]Real-time vitals tracking and telemetry.
Augmented reality [78]High speed video and data streaming.
Military uniforms [79]Tactical communication and positioning.

5.3. Automotive Radar and V2X Communication

In automotive systems, mmWave antennas are pivotal in enabling advanced driver-assistance systems (ADAS), radar-based obstacle detection, and vehicle-to-everything (V2X) communication. These applications demand highly directional antennas with narrow beamwidths, typically operating at 24 GHz, 60 GHz, or 77 GHz. Linear polarization is commonly used for radar sensing, while V2X systems may employ dual-polarized arrays for improved communication diversity. Their integration into vehicle bodies requires compact, conformal, and durable designs [80].

5.4. UAV and Satellite Communication

Unmanned aerial vehicles (UAVs) and satellite platforms benefit from mmWave antennas due to their high gain, lightweight construction, and beam-steering capabilities. Directional radiation patterns (gain > 15 dBi) are often required for long-range line-of-sight (LOS) and beyond-line-of-sight (BLOS) links. In UAVs, polarization selection depends on the flight environment; circular polarization is favored in multipath-prone or dynamic aerial scenarios. Conformal and low-profile antenna designs are preferred to minimize aerodynamic drag and preserve maneuverability. Table 7 presents mmWave applications in UAVs and satellites.

5.5. Imaging and Sensing Technologies

mmWave antennas enable high-resolution imaging and non-contact sensing in diverse fields including medical diagnostics, industrial inspection, and security screening. These applications benefit from short wavelengths, which yield fine spatial resolution. Antennas are often configured to provide narrow beams and controlled sidelobes for improved image clarity.
In wearable medical imaging, circular or dual-polarized antennas help reduce orientation sensitivity. In industrial applications, planar arrays provide wide scanning angles and adjustable beamwidths. Security screening systems at airports and public venues utilize mmWave antennas for detecting hidden threats without harmful ionizing radiation. In agriculture and environmental monitoring, mmWave sensors are used to assess soil moisture and detect pollutants. Table 8 presents applications of mmWave imaging and sensing in the healthcare, security, and industrial industries.

5.6. Biomedical Imaging and Health Monitoring

Millimeter-wave (mmWave) technologies are emerging as safe and high-resolution alternatives to traditional diagnostic tools in healthcare. Due to their short wavelength and ability to penetrate non-metallic materials, mmWave antennas have been explored for medical imaging techniques such as early-stage tumor detection, skin cancer screening, and breast tissue analysis. Compared with X-ray or CT imaging, mmWave imaging systems operate with low power and pose no ionizing radiation risks, making them suitable for repetitive or long-term monitoring. Moreover, mmWave signals exhibit strong sensitivity to changes in dielectric properties of biological tissues, enabling precise tissue characterization [86].
In wearable healthcare systems, mmWave antennas are being designed for body-worn and implantable devices that support wireless data exchange at gigabit rates. Applications include remote monitoring of vital signs such as heart rate, respiration, and body temperature using Doppler-based mmWave sensors. Wearable mmWave sensors embedded in textiles or flexible patches are showing promise for real-time monitoring of patients, with minimal interference from ambient conditions [87]. These antennas must meet stringent criteria, including low specific absorption rate (SAR), mechanical flexibility, and biocompatibility for safe long-term use. Table 9 presents mmWave antenna use cases in healthcare.

5.7. Environmental and Industrial Sensing

Beyond healthcare, mmWave antennas are finding applications in industrial sensing and environmental monitoring, where conventional sensing technologies may be inadequate. In industrial automation, mmWave radar systems are used for precision object detection, liquid level sensing, and non-contact monitoring in environments with poor visibility, such as dust, fog, and steam. These systems offer high resolution, compact form factors, and immunity to optical disturbances, making them suitable for structural health monitoring, industrial robotics, and factory automation [88].
In environmental monitoring, mmWave antennas are increasingly integrated into IoT sensor nodes and UAV platforms for detecting gases, measuring soil moisture, or mapping pollutant distributions. Due to their ability to capture fine spatial features and operate reliably in outdoor conditions, mmWave-based remote sensing systems are now being tested for applications like smart agriculture, atmospheric monitoring, and climate research [89]. Antenna designs for these applications focus on low-power operation, wide coverage, and resistance to harsh environmental factors such as temperature fluctuations and electromagnetic interference. Table 10 presents mmWave antenna use cases in environmental and industrial applications.

6. Discussion and Future Directions

The continuous evolution of millimeter-wave (mmWave) antenna technologies highlights a strong convergence of advanced design methodologies, material sciences, fabrication techniques, and cross-disciplinary integration. However, as mmWave antennas push the limits of miniaturization, functionality, and frequency, they also bring forth several challenges and opportunities that will shape future research. Table 11 presents targeted future directions with suggested research pathways.
One of the most pressing challenges is balancing compactness with performance. As antennas become more compact and integrated into non-traditional platforms—such as wearables, IoT devices, and flexible substrates—engineers must ensure that performance metrics like gain, efficiency, and bandwidth are not compromised. Advances in fractal designs, metasurfaces, and AI-driven optimization algorithms are showing promise in overcoming this limitation by enabling adaptive, space-efficient antenna structures.
For instance, future research could explore: “How can topology optimization algorithms guided by genetic algorithms or particle swarm optimization be applied to co-design miniaturized antennas with wideband behavior?” This direction can help identify optimal structures that trade-off between footprint, performance, and mechanical flexibility for wearable and conformal applications.
Another key area is beamforming and beam-steering. Although current analog, digital, and hybrid beamforming techniques have made impressive strides, issues like power consumption, cost, and latency still limit their practical implementation, especially in massive MIMO systems. Future work may focus on energy-aware beamforming strategies using deep reinforcement learning (DRL), particularly for mobile platforms.
One relevant hypothesis is: “Can DRL-based agents be trained to dynamically select beam directions and configurations in UAV-based mmWave networks under varying channel conditions and mobility constraints?”
Material innovations will also play a crucial role. The development of new tunable and smart materials—such as graphene, liquid metals, and phase-change materials—can lead to reconfigurable antennas that adapt in real time to environmental and user conditions. Moreover, green materials that are biodegradable or biocompatible will be vital for wearables and implantable devices.
Future research may address: “What role can graphene-metal hybrid composites play in tunable wearable mmWave antennas, and how do their thermal and mechanical reliability compare to conventional copper-based designs?”
Artificial intelligence (AI) is increasingly shaping the design and optimization of mmWave antennas through data-driven and model-free techniques. For example, deep reinforcement learning (DRL) has been applied for real-time beam selection in mmWave vehicular environments, where a DRL agent achieved near-optimal beam prediction accuracy using contextual sensing data [90]. In another case, a convolutional neural network (CNN) was utilized to optimize reflectarray configurations for beam steering, demonstrating performance comparable to traditional full-wave simulations while significantly reducing computational time [91].
In the domain of antenna geometry design, generative models have been applied to synthesize novel patch antenna layouts with targeted resonance and gain characteristics, validated through both simulation and measurement [92]. Evolutionary algorithms such as genetic algorithms and particle swarm optimization have also been employed to automate impedance matching and bandwidth tuning, with optimized antenna structures subsequently fabricated and tested for experimental validation [93].
AI also aids in mitigating multipath fading and channel estimation in massive MIMO systems, particularly through hybrid beamforming and channel prediction. Despite these advances, challenges remain, particularly the need for large annotated datasets, high training costs, and the interpretability of AI-driven design choices in safety-critical systems.
Quantum technologies, although in early stages, open fascinating possibilities for mmWave systems. Quantum materials such as topological insulators, graphene, and superconductors exhibit desirable high-frequency behavior, low-loss conduction, and extreme tunability. These materials may enable antennas with reconfigurable beam patterns and quantum signal compatibility. Integrating mmWave antennas with quantum key distribution (QKD) or superconducting circuits for secure communication presents a novel multidisciplinary challenge. Key limitations include cryogenic cooling, fabrication scalability, and a lack of robust hybrid integration platforms.
Despite the extensive research and significant progress in the field of millimeter-wave (mmWave) antennas and antenna arrays, several limitations persist that warrant careful consideration. Firstly, many experimental and simulation-based studies focus on ideal conditions, often failing to replicate realistic environments such as urban clutter, human body effects for wearable antennas, and dynamic UAV platforms. This limits the generalizability of reported performance metrics like gain, beam-steering accuracy, and bandwidth. Secondly, the lack of standardized testing protocols across studies introduces inconsistencies in performance evaluation, making direct comparison between designs difficult. Thirdly, while emerging technologies such as metamaterials, reconfigurable surfaces, and AI-driven beamforming show promise, most research is still in early prototyping stages and lacks long-term reliability data. Additionally, thermal management, fabrication complexity at higher frequencies, and the high cost of mmWave components remain practical challenges. Finally, the review identified a shortage of experimental validation for many proposed antenna designs, especially for applications like automotive radar and body-worn sensors. These limitations highlight the need for more interdisciplinary, system-level research that integrates antenna design with real-world constraints and deployment scenarios.
In particular, a gap remains between simulation-based and real-world measurements. Numerous studies demonstrate impressive simulated performance—such as high gain or wide bandwidth—but fail to report measurements under realistic operating conditions. Discrepancies often arise due to fabrication tolerances, substrate inconsistencies, and environmental factors, which are not fully captured in simulations. This emphasizes the importance of experimental validation to ensure antenna reliability and consistency across practical deployments. Establishing standardized test methodologies and benchmarking protocols will be crucial for accurately evaluating mmWave antenna designs and facilitating fair comparison across future works.

Limitations and Trade-Offs in Current mmWave Antenna Technologies

Despite substantial advancements, mmWave antenna technologies still face persistent limitations that hinder large-scale deployment and consistent performance across applications. One major issue is high signal attenuation, especially at frequencies above 30 GHz. While directional beamforming helps mitigate this, the narrow beamwidth introduces alignment challenges in dynamic scenarios such as UAV communication or mobile wearables. Antennas designed for high gain often suffer from restricted bandwidth or poor omnidirectionality, making trade-offs unavoidable between directivity and coverage.
Material constraints further exacerbate these challenges. Conventional dielectric materials exhibit increased loss tangents at mmWave frequencies, leading to significant dielectric and conductor losses. Although low-loss materials like Rogers and Taconic substrates have improved efficiency, they come at a higher cost and limited mechanical flexibility, making them less ideal for wearables or conformal designs. Flexible alternatives such as PDMS or polyimide offer mechanical adaptability but typically degrade electrical performance under bending or thermal stress.
Fabrication limitations are also significant. High-resolution techniques like photolithography or laser direct structuring (LDS) can achieve fine geometries but are often expensive and not scalable. Additive manufacturing methods like inkjet printing are promising for low-cost, flexible designs, yet suffer from issues such as ink conductivity variability, surface roughness, and delamination over time. Moreover, there remains a lack of unified standards for evaluating these antennas across simulation, fabrication, and experimental testing.
Lastly, the integration of antennas with electronics, especially in AiP (antenna-in-package) configurations, often leads to electromagnetic interference and mutual coupling challenges. Designers must navigate trade-offs between compact integration, thermal management, and consistent impedance matching. Addressing these limitations requires interdisciplinary solutions combining materials science, RF circuit co-design, and scalable manufacturing innovations.

7. Conclusions

Millimeter-wave antennas and antenna arrays have emerged as indispensable components for enabling high-speed, high-capacity, and low-latency communication systems, as well as advanced sensing and imaging applications. This review presented a comprehensive overview of the current state of mmWave antenna technologies, covering the fundamental principles, design and optimization strategies, materials and fabrication methods, integration techniques, and diverse application domains.
Significant progress has been made in beamforming and beam-steering systems, compact and wearable antennas, and MIMO-based architectures. Innovations in materials science and fabrication technologies have further enabled highly efficient, flexible, and conformal antenna designs suited for emerging domains like wearable electronics, UAVs, and intelligent transportation systems. Moreover, mmWave antennas are playing an increasingly vital role in applications beyond communications, such as biomedical monitoring, automotive radar, and environmental sensing.
Nonetheless, several challenges remain, particularly in enhancing performance without increasing complexity or cost, and ensuring seamless integration into heterogeneous platforms. Future research will need to address these challenges through AI-driven design automation, smart materials, sustainable manufacturing, and co-designed hardware–software systems.
In conclusion, the interdisciplinary synergy between antenna engineering, material science, and communication theory continues to push the boundaries of mmWave technology. As researchers explore new frontiers such as terahertz communication and quantum-enabled networks, mmWave antennas will remain a foundational technology driving innovation across scientific and industrial domains.

Author Contributions

Conceptualization, F.M.; methodology, F.M.; validation, A.M.; formal analysis, A.M.; resources, A.M.; writing—original draft preparation, F.M.; writing—review and editing, A.M.; supervision, A.M. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Data Availability Statement

Data sharing is not applicable.

Conflicts of Interest

The authors declare no conflicts of interest.

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Electronics 14 02705 g001
Figure 1. Systematic selection of articles using PRISMA methodology.
Figure 1. Systematic selection of articles using PRISMA methodology.
Electronics 14 02705 g001
Table 1. Summary of key research papers on mmWave antennas.
Table 1. Summary of key research papers on mmWave antennas.
TitleAim of PaperResearch FindingsConclusion
Compact UWB MIMO Antenna for 5G Millimeter-Wave Applications [13]Design a compact ultra-wideband MIMO antenna for 5G mmWave applications.Proposed a compact UWB MIMO antenna with high isolation and wide bandwidth suitable for 5G applications.Demonstrated the feasibility of compact MIMO antennas for high-speed 5G communications.
A Survey on Millimeter-Wave Beamforming Enabled UAV Communications and Networking [14]Provide a comprehensive survey on mmWave beamforming for UAV communications.Reviewed mmWave antenna structures, channel modeling, and beamforming techniques for UAVs.Identified challenges and future research directions in mmWave UAV communications.
Overview of Millimeter Wave Communications for Fifth-Generation (5G) Wireless Networks [15]Overview of mmWave communications with a focus on propagation models for 5G.Compared propagation parameters and channel models over 0.5–100 GHz range.Highlighted the importance of accurate channel models for mmWave 5G deployment.
A Miniaturized Antenna for Millimeter-Wave 5G-II Band Communication [16]Design a miniaturized antenna for 5G-II band communication.Developed a compact antenna with improved gain and bandwidth for 5G-II band.Validated the antenna’s suitability for compact 5G devices.
A Comprehensive Review on Millimeter Waves Applications and Antennas [17]Review mmWave applications and antenna designs.Discussed various mmWave antenna models and their applications in high-speed data transmission.Emphasized the potential of mmWave technology in future communication systems.
Hybrid Beamforming for 5G and Beyond Millimeter-Wave Systems: A Holistic View [18]Present a holistic view on hybrid beamforming for 5G mmWave systems.Compared different hardware structures and beamforming algorithms for efficiency and performance.Identified promising hybrid beamforming techniques for future wireless networks.
Ultra-wideband Antenna System Design for Future mmWave Applications [19]Design an ultra-wideband antenna system for future mmWave applications.Proposed an antenna system with enhanced bandwidth and gain for mmWave applications.Demonstrated the system’s potential for next-generation wireless communications.
Millimeter Wave Sensing: A Review of Application Pipelines and Building Blocks [20]Review mmWave sensing applications and building blocks.Analyzed hardware, algorithms, and models for mmWave sensing applications.Provided insights into the development of mmWave sensing technologies.
Metamaterial Inspired Millimeter-Wave Antenna Arrays for 5G Wireless Applications [21]Design metamaterial-inspired mmWave antenna arrays for 5G.Developed single and array antenna designs with improved performance using metamaterials.Showed the effectiveness of metamaterials in enhancing antenna performance.
Five-Band Millimeter-Wave Antenna of Circular/Linear Polarization for Forthcoming Generations of Mobile Handsets [22]Develop a five-band mmWave antenna with circular/linear polarization for mobile handsets.Designed an antenna supporting multiple bands with dual polarization for enhanced performance.Validated the antenna’s applicability for future mobile handsets.
Performance improvement of millimeter wave antennas (review) [23]Review performance improvement techniques for mmWave antennas.Discussed various methods to enhance bandwidth, gain, and efficiency of mmWave antennas.Provided a comprehensive overview of performance enhancement strategies.
Design of a Compact Millimeter Wave Antenna for 5G Applications based on Meta Surface Luneburg Lens [24]Design a compact mmWave antenna using a metasurface Luneburg lens for 5G.Proposed an antenna design with improved directivity and compactness using metasurface lens.Demonstrated the design’s potential for 5G applications.
Review on Millimeter Wave Antennas- Potential Candidate for 5G Enabled Applications [25]Review mmWave antennas as potential candidates for 5G applications.Analyzed various mmWave antenna designs and their suitability for 5G.Highlighted the importance of mmWave antennas in 5G networks.
Millimeter wave antenna with enhanced bandwidth for 5G wireless application [26]Design a mmWave antenna with enhanced bandwidth for 5G applications.Developed an antenna with improved bandwidth and stable radiation patterns at 28 GHz.Validated the antenna’s performance for 5G applications.
High Performance 5G FR-2 Millimeter-Wave Antenna Array for Point-to-Point and Point-to-Multipoint Operation [27]Design high-performance mmWave antenna arrays for 5G FR-2 band.Developed 8-element linear and 32-element planar arrays with high gain and beamwidth control.Demonstrated the arrays’ suitability for various 5G applications.
Antenna Design for Microwave and Millimeter Wave Applications II: Latest Advances and Prospects [28]Review latest advances in antenna design for microwave and mmWave applications.Summarized recent developments in antenna miniaturization, optimization, and array configurations.Provided insights into future prospects of antenna design.
Design of multiband MIMO antenna for 5G millimeterwave application [29]Design a multiband MIMO antenna for 5G mmWave applications.Proposed a multiband MIMO antenna with improved isolation and bandwidth.Demonstrated the antenna’s effectiveness for 5G applications.
MIMO antenna array for mm-wave 5G smart devices [30]Develop a MIMO antenna array for mmWave 5G smart devices.Designed a compact MIMO antenna array with enhanced performance for smart devices.Validated the design’s applicability for 5G smart devices.
A dual-polarized cavity-backed aperture antenna for 5G mmW MIMO applications [31]Design a dual-polarized cavity-backed aperture antenna for 5G mmWave MIMO applications.Developed an antenna with improved isolation and bandwidth for MIMO systems.Demonstrated the antenna’s suitability for 5G MIMO applications.
Multiband microstrip patch antenna for 5G wireless applications using MIMO techniques [32]Design a multiband microstrip patch antenna for 5G using MIMO techniques.Proposed an antenna with multiple bands and improved performance for 5G MIMO systems.Validated the antenna’s effectiveness for 5G applications.
mmWall: Steerable Transflective Metamaterial Surface [33]Real-time indoor beam relay through wallsDemonstrated full 360° steering with 91% outage-free coverage; SNR boost up to 30 dBProgrammable metasurface provides robust mmWave coverage
High-Gain Metasurface Lens Antenna for mmWave Radar [34]Design of lens-integrated metasurface antennaAchieved >15 dBi gain and narrow beams using metasurface lens elementCompact, high-gain mmWave radar antenna enabled
Hybrid Antenna–Metasurface Architecture for mmWave/THz MIMO [35]Integrate passive metasurface with active MIMO arrayAchieved steerable pencil beams, reduced RF chain countsHybrid arrays improve efficiency and reduce complexity
High-Gain Metasurface-Integrated Planar Antenna [36]Enhance planar antenna via metasurface reflectorMeasured ∼9 dBi gain across 23–39 GHz bandwidthReflector metasurface significantly boosts gain and bandwidth
Metasurface Filter Antenna Array with Ridge-Gap Waveguide [37]Improve beam steering and filtering via metasurface + RGWAchieved dual-polarized wideband performance, low sidelobesCompact high-performance filter-array design
Metasurface Antenna for 28 GHz RoF [38]Enhance gain and EVM in radio-over-fiber linkGain improved, EVM reduced from 3.7% to 2.7% using superstrateMetasurface superstrate effectively boosts RoF link performance
Deep Learning Coordinated Beamforming [39]ML-assisted beamforming for mobile mmWave linksApproaches genie-aided beam selection, reduces training overheadAI methods enable efficient beamforming
IRS-Assisted mmWave Communication [40]Joint EP + active precoding with intelligent reflecting surfacesQuadratic gain scaling with number of reflectors, robust to blockageIRSs offer effective blockage mitigation
Smart Surface-Enabled 5G mmWave Networking [41]Programmable roadside metasurfaces for mmWave relaysAchieved robust coverage with real-time beam controlLow-power metasurface aids pervasive urban mmWave
Dynamic Metasurface Antennas for Uplink Massive MIMO [42]Realize uplink MIMO with dynamic metasurface antenna arraysAchieved adaptive beam patterns with few-bit controlD-MIMO arrays present energy-efficient massive MIMO solution
A Reconfigurable Metasurface for Beam Steering in 5G mmWave Systems [43]To design and experimentally validate a metasurface-based antenna capable of dynamic beam steering for 5G mmWave applications.The proposed metasurface demonstrated rapid beam steering over ±30° with high gain (15 dBi) and low sidelobe levels, verified through full-wave simulation and prototype measurements.The metasurface antenna offers a compact, efficient solution for next-generation mmWave beamforming, improving link reliability in dynamic environments.
AI-Driven Topology Optimization of mmWave Antennas Using Deep Learning [44]To develop a deep learning framework for automatic design and optimization of mmWave antennas with complex topologies.The AI approach accelerated design cycles by 80% and produced antenna layouts with enhanced impedance bandwidth and gain, validated by simulations and fabricated prototypes.Deep learning enables efficient exploration of large design spaces, pushing the limits of antenna performance and manufacturability.
Quantum Metasurface Antennas for Enhanced Wireless Communications [45]To explore the integration of quantum materials with metasurface antennas to enhance signal coherence and reduce noise at mmWave frequencies.Experimental results showed improved signal-to-noise ratio and coherence times due to quantum material properties, supported by theoretical modeling.Quantum metasurfaces present a promising path for ultra-low noise mmWave communication systems, with potential impact on secure and high-capacity links.
Table 2. Comparative analysis of beamforming techniques in mmWave systems.
Table 2. Comparative analysis of beamforming techniques in mmWave systems.
TypeKey CharacteristicsUse CasesTypical Data RatePros and Cons
Analog Beamforming [47]RF-phase-shifter based single-beam steeringIoT devices, low-power mmWave linksUp to 1 Gbps+ Low power, low cost
- Limited flexibility, supports only one beam
Digital Beamforming [48]Digital baseband control for multiple beams and MIMO supportMassive MIMO, adaptive radar, SDRsUp to 10 Gbps+ High flexibility, ideal for dynamic environments
- Expensive, high power consumption
Hybrid Beamforming [49]Combines analog and digital control for multiple streams with fewer RF chains5G NR base stations, mmWave backhaul5–10 Gbps (depending on streams)+ Trade-off between performance and cost
- Moderate complexity, harder calibration
Table 3. Performance-oriented comparison of MIMO array structures.
Table 3. Performance-oriented comparison of MIMO array structures.
MIMO Array TypeStructureCoverage PatternTypical Gain (dBi)Isolation (dB)Use Cases
Planar [52]Two-dimensional flat surfaceNarrow/sector-based (up to  120°)6–9 dBi15–20 dBBest suited for smartphones and handheld devices due to ease of integration and low-profile form factor. Limited coverage unless multiple arrays are used.
Cylindrical [53]Curved around cylinder or bodyOmnidirectional, 360° azimuth8–12 dBi18–25 dBIdeal for mobile platforms such as UAVs and vehicle-mounted systems. Provides nearly full azimuthal coverage with moderate complexity.
Massive MIMO [54]Large-scale planar or 3D gridsHighly directional, narrow beams with high spatial resolution15–25 dBi (array gain)>25 dBUsed in 5G/6G macro base stations. Offers significant spectral efficiency, beam steering, and spatial multiplexing for dense urban environments. Requires extensive calibration and computational resources.
Table 4. Comparison of advanced fabrication techniques for mmWave antennas.
Table 4. Comparison of advanced fabrication techniques for mmWave antennas.
Fabrication MethodResolution/PrecisionScalability and CostStrengths and Limitations
PCB Etching∼100 μmHigh scalability, low costStandard, but limited for 3D/conformal shapes
Inkjet Printing∼50–100 μmLimited throughput, moderate costSuitable for flexible substrates; durability and uniformity concerns
Aerosol Jet Printing<50 μmModerate scalability, high costHigh resolution; useful for complex geometries
LDS (Laser Direct Structuring)∼100 μmMedium scalability, high initial costConformal 3D patterning; dependent on special polymers
Photolithography<10 μmLow scalability, very high costHigh precision; ideal for MMICs, not flexible or low-cost
Table 5. Key benefits of mmWave antennas in wireless communication.
Table 5. Key benefits of mmWave antennas in wireless communication.
FeaturesBenefits
High bandwidthGigabit data rates.
Compact array integrationSmall cell and user terminal support.
Beamforming/MIMO capabilitiesEnhanced spectral and energy efficiency.
Table 7. mmWave applications in UAVs and satellites.
Table 7. mmWave applications in UAVs and satellites.
PlatformUse CaseFrequency Bands
UAVs [81]Real-time surveillance, control28 GHz, 60 GHz
Satellites [82]Earth observation, broadband delivery30 GHz (Ka-band)
Table 8. mmWave imaging and sensing applications.
Table 8. mmWave imaging and sensing applications.
SectorApplicationAdvantage
Healthcare [83]Tumor detection, skin diagnosticsHigh spatial resolution
Security [84]Concealed object detectionNon-ionizing, safe scanning
Industrial [85]Material defect inspectionPenetration through surfaces
Table 9. Representative mmWave antenna use cases in healthcare.
Table 9. Representative mmWave antenna use cases in healthcare.
Use CaseAntenna Design RequirementsApplication Type
Skin/breast cancer detectionHigh resolution, non-ionizing, accurate tissue characterizationImaging
Vital sign monitoring (respiration, heartbeat)Doppler sensing, real-time monitoring, integration into fabricsWearable sensing
Wireless implant communicationsMiniaturized, biocompatible, low-SARBiomedical telemetry
Table 10. Representative mmWave antenna use cases in environmental and industrial applications.
Table 10. Representative mmWave antenna use cases in environmental and industrial applications.
Use CaseAntenna Design RequirementsApplication Type
Pipe crack detection and fluid-level sensingDurable, radar-optimized, high accuracy in harsh conditionsIndustrial monitoring
UAV-based air quality monitoringLightweight, wide-area coverage, low powerEnvironmental sensing
Soil moisture and smart agriculture sensorsWeather-resistant, compact form, IoT-compatiblePrecision agriculture
Table 11. Targeted future directions with suggested research pathways.
Table 11. Targeted future directions with suggested research pathways.
AreaCurrent StatusFuture Directions and Research Questions
Antenna MiniaturizationPerformance–size trade-offs using conventional planar designsUse fractal or metasurface-based geometries optimized via machine learning.
Research Q: How can evolutionary algorithms optimize compact mmWave antennas while maintaining multiband and wideband performance?
Beamforming and SteeringAnalog/digital/hybrid systems with limitations in power and latencyApply deep reinforcement learning for adaptive beam control in dynamic environments.
Research Q: How can DRL be used for real-time beam selection in UAV networks under mmWave conditions?
MaterialsLimited to static or linear dielectric materialsDevelop tunable and biocompatible materials such as graphene, LCP, and phase-change materials.
Research Q: Can liquid-metal-based substrates provide self-healing and tunable radiation behavior?
Fabrication Techniques2D PCB and limited 3D/inkjet methodsCombine inkjet, laser, and roll-to-roll processes for flexible, multilayer antenna structures.
Research Q: How can multimaterial additive manufacturing be used to produce wearable mmWave antennas with conformal curvature?
Application Expansion5G/6G, radar, imaging, wearablesExplore sub-THz systems, quantum networks, and integrated sensing.
Research Q1: How can mmWave antennas be co-designed with quantum components for secure, cryogenic communications?
Research Q2: What are the trade-offs when integrating sensing and communication within a shared mmWave platform?
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Mehmood, F.; Mehmood, A. Recent Advancements in Millimeter-Wave Antennas and Arrays: From Compact Wearable Designs to Beam-Steering Technologies. Electronics 2025, 14, 2705. https://doi.org/10.3390/electronics14132705

AMA Style

Mehmood F, Mehmood A. Recent Advancements in Millimeter-Wave Antennas and Arrays: From Compact Wearable Designs to Beam-Steering Technologies. Electronics. 2025; 14(13):2705. https://doi.org/10.3390/electronics14132705

Chicago/Turabian Style

Mehmood, Faisal, and Asif Mehmood. 2025. "Recent Advancements in Millimeter-Wave Antennas and Arrays: From Compact Wearable Designs to Beam-Steering Technologies" Electronics 14, no. 13: 2705. https://doi.org/10.3390/electronics14132705

APA Style

Mehmood, F., & Mehmood, A. (2025). Recent Advancements in Millimeter-Wave Antennas and Arrays: From Compact Wearable Designs to Beam-Steering Technologies. Electronics, 14(13), 2705. https://doi.org/10.3390/electronics14132705

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