Lens Antenna Research Articles

Performance Analysis and Design Considerations of the Near-Field-Focused Rotman Lens Antennas

This study investigates the application of Rotman lens antennas in the near field. The design equations of these antennas have been derived in the near field and demonstrated to be highly effective. By considering specific examples, the shapes of the inner surfaces of these lens antennas have been analyzed and discussed, revealing how practically realizable lens surfaces can be designed. As these Rotman lenses are perfect at only three points in the near field, they exhibit phase errors at other points along a line connecting the three near-field focal points, resulting in deterioration of the near-field patterns. It has been shown that by selecting the lens parameters appropriately, these phase errors can be kept to a minimum, causing only minimal beam deterioration. Compared to far-field-focused Rotman lens antennas, near-field-focused Rotman lens antennas achieve significantly higher power levels, having 3.8 to 6.3 dB improvement for different beams of a 17-element array. The study has demonstrated the potential of Rotman lenses as multiple beamforming antennas for near-field applications.

Monolithically Structured van der Waals Materials for Volume-Polariton Refraction and Focusing.

Polaritons, hybrid light and matter waves, offer a platform for subwavelength on-chip light manipulation. Recent works on planar refraction and focusing of polaritons all rely on heterogeneous components with different refractive indices. A fundamental question, thus, arises whether it is possible to configure two-dimensional monolithic polariton lenses based on a single medium. Here, we design and fabricate a type of monolithic polariton lens by directly sculpting an individual hyperbolic van der Waals crystal. The in-plane polariton focusing through sculptured step-terraces is triggered by geometry-induced symmetry breaking of momentum matching in polariton refractions. We show that the monolithic polariton lenses can be robustly tuned by the rise of van der Waals terraces and their curvatures, achieving a subwavelength focusing resolution down to 10% of the free-space light wavelength. Fusing with transformation optics, monolithic polariton lenses with gradient effective refractive indices, such as Luneburg lenses and Maxwell's fisheye lenses, are expected by sculpting polaritonic structures with gradually varied depths. Our results bear potential in planar subwavelength lenses, integrated optical circuits, and photonic chips.

Additively-Manufactured Broadband Metamaterial-Based Luneburg Lens for Flexible Beam Scanning

Multi-beam microwave antennas have attracted enormous attention owing to their wide range of applications in communication systems. Here, we propose a broadband metamaterial-based multi-beam Luneburg lens-antenna with low polarization sensitivity. The lens is constructed from additively manufactured spherical layers, where the effective permittivity of the constituting elements is obtained by adjusting the ratio of dielectric material to air. Flexible microstrip patch antennas operating at different frequencies are used as primary feeds illuminating the lens to validate the radiation features of the lens-antenna system. The proposed Luneburg lens-antenna achieves ±72° beam scanning angle over a broad frequency range spanning from 2 GHz to 8 GHz and presents a gain between 15.3 dBi and 22 dBi, suggesting potential applications in microwave- and millimeter-wave mobile communications, radar detection and remote sensing.

The Evolution of Printed Lens and Transmitarray Antennas: Navigating representative past, present, and future designs and manufacturing techniques

The Evolution of Printed Lens and Transmitarray Antennas: Navigating representative past, present, and future designs and manufacturing techniques

Beamspace Waveform Design and Beam Selection for Lens Antenna Array-Assisted ISAC Systems

Beamspace Waveform Design and Beam Selection for Lens Antenna Array-Assisted ISAC Systems

3D‐printed high‐gain beam‐switching dielectric transmitarray fed by an integrated lens antenna

AbstractThis article presents a high‐gain linearly polarized three‐dimensionally‐printed dielectric transmitarray with an integrated lens antenna (ILA) as a feed source. The proposed transmitarray contains 1336 unit cells of 16 different types with a gradual phase change of 22.5°. The unit cells have a cross‐section of 5.4 × 5.4 mm, and their height varies from 0 to 24.2 mm for different gradual phase changes. The designed transmitarray shows a maximum gain of 19.5 dBi at 28 GHz with a 3‐dB beamwidth of less than 7° in both the E‐ and H‐planes. Furthermore, a holder with seven distinct feed positions has been designed to alter the location of the feed antenna in the focal plane of the transmitarray. The main beam can be switched by exciting these feeds individually. In addition, it has an impedance bandwidth (|S11 | <−10 dB) from 24.5 GHz to 32.5 GHz for all the feed positions. The proposed antenna system is a good candidate for radar, wireless power transmission, and high‐power military applications.

Unveiling New IoT Antenna Developments: Planar Multibeam Metasurface Half-Maxwell Fish-Eye Lens with Wavelength Etching

This study introduces a groundbreaking antenna system, the directive Metasurface Half-Maxwell Fish-Eye (MHMF) lens antenna, tailored specifically for Internet-of-Things (IoT) networks. Designed to operate at 60 GHz, this antenna ingeniously integrates a dipole antenna within a parallel-plate waveguide to illuminate a Half-Maxwell Fish-Eye (HMFE) lens. The HMFE lens serves as a focal point, enabling a crucial high gain for IoT operations. The integration of metasurface structures facilitates the attainment of the gradient refractive index essential for the lens surface. By employing commercial Ansys HFSS software, extensive numerical simulations were conducted to meticulously refine the design, focusing particularly on optimizing the dimensions of unit cells, notably the modified H-shaped cells within the parallel waveguides housing the beam launchers. A functional prototype of the antenna was constructed using a standard PCB manufacturing process. Rigorous testing in an anechoic chamber confirmed the functionality of these manufactured devices, with the experimental results closely aligning with the simulated findings. Far-field measurements have further confirmed the effectiveness of the antenna, establishing it as a high-gain antenna solution suitable for IoT applications. Specifically, it operates effectively within the 60 GHz range of the electromagnetic spectrum, which is crucial for ensuring reliable communication in IoT devices. The directive HMFE lens antenna represents a significant advancement in enhancing IoT connectivity and capabilities. Leveraging innovative design concepts and metasurface technology, it heralds a new era of adaptable and efficient IoT systems.

Broadband generation of a multi-polarization multi-beam using a receiving-transmitting metasurface

Generating multiple beams in distinct polarization states is promising in multi-mode wireless communication but still remains challenging in metasurface design. Here, we theoretically and experimentally demonstrate a concept of broadband receiving-transmitting metasurface and its application to the generation of multi-polarization multi-beam. By employing U-slot patch, an efficient receiving-transmitting element with full phase coverage is designed within a wide bandwidth. Based on this architecture, a methodology is proposed to generate dual spin-decoupled beams and then developed into the strategy of generating multiple beams at different linear polarizations. To verify our strategy, two lens antennas, respectively radiating dual-spin dual-beam and quad-polarization quad-beam, are devised. With multi-polarization multi-beam radiated, the two lens antennas are both with whole aperture efficiency above 40% within the bandwidth of 10.6–12.3 GHz (14.8%), firmly validating our strategy and design.

A High-Gain Tapered Slot Antenna Based on Spoof Surface Plasmon Polaritons Director and Horn-Shaped Dielectric Lens

A High-Gain Tapered Slot Antenna Based on Spoof Surface Plasmon Polaritons Director and Horn-Shaped Dielectric Lens

Corners‐slotted wideband patch antenna gain enhancement with a 3D dielectric lens for Ka‐band satellite communication

SummaryTo improve the gain of the corner‐slotted, wideband microstrip patch antenna (MPA), a three‐dimensional (3D) hemispherical dielectric lens (DL) and dielectric cylinder‐based hybrid structure is introduced. DL is constructed and integrated on the surface of the patch antenna to increase the gain performance. Three‐dimensional printing techniques contribute considerably to lens production. The 3D manufacturing technique provides greater freedom and versatility than conventional manufacturing methods. The DL increased the proposed single‐patch antenna gain from 6.2 to 13.7 dBi with stable gain fluctuation in the working frequency spectrum spanning between 27.5 and 31 GHz. This implies a notable increase in gain of 7.5 dBi and a consistently uniform gain characteristic throughout a 5‐GHz wide frequency range. Furthermore, the DL‐loaded antenna parameters such as |S11|, gain (dBi), axial ratio (AR), radiation efficiency (%), and radiation patterns measured results are compared with simulated plots. Overall, the measured results agree well with the simulated findings. Based on the results, the compact antenna can be chosen for different wireless applications, especially for satellite communication in the proposed band.

Over-the-Air Characterization of a Steerable Sub-THz Si Lens and On-Chip Antenna System

Over-the-Air Characterization of a Steerable Sub-THz Si Lens and On-Chip Antenna System

2-D Multibeam Leaky-Wave Antenna Based on Modified Luneburg Lens

2-D Multibeam Leaky-Wave Antenna Based on Modified Luneburg Lens

Mismatched Luneburg Lenses: Numerical Analysis and Design Rules

Mismatched Luneburg Lenses: Numerical Analysis and Design Rules

High-Gain Circularly Polarized 500–750 GHz Lens Antenna Enabled by Silicon Micromachining

High-Gain Circularly Polarized 500–750 GHz Lens Antenna Enabled by Silicon Micromachining

Beam Tracking Assisted High Mobility V2I Communications With Extremely Large Lens Antenna Array

Beam Tracking Assisted High Mobility V2I Communications With Extremely Large Lens Antenna Array

Series-Fed Integrated Lens Antenna for High Gain in Millimeter-Wave Band

Series-Fed Integrated Lens Antenna for High Gain in Millimeter-Wave Band

A Volumetric Waveguide-Type Rotman Lens Antenna for Three-Dimensional Millimeter-Wave Beamforming.

In this paper, a volumetric Rotman lens antenna operating at 28 GHz is proposed. The design formula and procedure were derived for the 3-D Rotman lens antenna. The number of tilted beams is 3 × 3. The six rectangular blocks are assembled using a metallic bolt. The input port consists of a waveguide, and the output port is made of an open-ended waveguide. The input and output waveguides are drilled in a flat conducting plate. The input and output port positions are optimized. Simulated and measured results show that the radiating beam is controlled almost exactly as calculated. Compared with the previous two-stage stacked Rotman lens antenna, the proposed Rotman lens antenna can dramatically decrease the antenna volume by approximately 75%.

Review of Luneburg Lens Antenna Designs Manufactured Using 3D Printing

Introduction. The interest in multibeam dielectric lens antenna arrays has been growing in recent years due to the development of millimeter-wave telecommunication and radar systems. Progress in the development of mobile communication systems based on adaptive beamforming technology is increasingly associated with multibeam systems based on lens antenna structures, providing an alternative to hard-to-implement and energy-consuming phased antenna arrays. In recent years, spherical and cylindrical Luneburg lens antennas implemented using additive manufacturing technology have attracted research attention. Despite their complexity of execution, these design exhibit excellent electromagnetic characteristics. This paper provides a review of Luneburg lens antennas manufactured using 3D printing, which can find application in 5G and 6G communication systems.Aim. To review achievements in the design of lens antenna structures manufactured using additive manufacturing.Materials and methods. Materials for analysis, comparison, and systematization were derived from various sources, including research articles, publications in proceedings of Russian and international conferences, and websites of manufacturers of lens antennas over the past 20 years. The material selection mechanism was based on the originality of the presented designs of printed Luneburg lens antennas.Results. A review of Luneburg lens antennas manufactured using 3D printing, which differ from each other in terms of mechanical strength, complexity of execution, and electrodynamic characteristics, was carried out. The results of a comparative analysis of the key characteristics of these antennas are presented, along with examples of their practical implementation.Conclusion. The disadvantage of Luneburg lens antennas has always been the complexity of their manufacture; however, additive manufacturing technologies open up new opportunities for their fast, high-quality, and automated production. Various 3D printing technologies can be used to create dielectric lens antennas, which differ in the resolution of printers, printing speed, and cost. Additive manufacturing methods are constantly developing, having reached the technological possibility of printing Luneburg lens for the sub-THz range with a high level of resolution and accuracy. In addition, 3D printers capable of printing multiple lenses simultaneously have also appeared.

Advancing into Millimeter Wavelengths for IoT: Multibeam Modified Planar Luneburg Lens Antenna with Porous Plastic Material

This paper introduces an innovative antenna design utilizing a cylindrical dielectric Luneburg lens tailored for 60 GHz Internet of Things (IoT) applications. To optimize V-band communications, the permittivity of the dielectric medium is strategically adjusted by precisely manipulating the physical porosity. In IoT scenarios, employing a microstrip dipole antenna with an emission pattern resembling cos10 enhances beam illumination within the waveguide, thereby improving communication and sensing capabilities. The refractive index gradient of the Luneburg lens is modified by manipulating the material’s porosity using air holes, prioritizing signal accuracy and reliability. Fabricated with polyimide using 3D printing, the proposed antenna features a slim profile ideal for IoT applications with space constraints, such as smart homes and unmanned aerial vehicles. Its innovative design is underscored by selective laser sintering (SLS), offering scalable and cost-effective production. Measured results demonstrate the antenna’s exceptional performance, surpassing IoT deployment standards. This pioneering approach to designing multibeam Luneburg lens antennas, leveraging 3D printing’s porosity control for millimeter-wave applications, represents a significant advancement in antenna technology with scanning ability between −67 and 67 degrees. It paves the way for enhanced IoT infrastructure characterized by advanced sensing capabilities and improved connectivity.

Enhanced Performance of Fe/WO3 Terahertz Dielectric Lenses

AbstractHerein transparent iron nanosheets deposited by the ionic coating technique onto glass and WO3 dielectric lenses are studied and characterized. The thickness of Fe nanosheets is varied in the range of 70–350 nm. It is observed that the transmittance and reflectance of the Fe nanosheets are highly affected by the layer roughness. Coating of iron nanosheets onto WO3 dielectric lenses increases the light absorption of WO3 by more than 240 times and red‐shifts the energy bandgap. Remarkable enhancements in the dielectric constant and in the optical conductivity are achieved via Fe coatings. In addition, iron coated dielectric lenses show higher terahertz cutoff limits varying in the range of 1.0–30 THz. Iron nanosheets remarkably increase the free charge carrier density and plasmon frequency in the infrared range of light. Moreover, the temperature dependent electrical conductivity shows high temperature stability and an increased electrical conductivity by more than 7 orders of magnitude by coating WO3 with 70 nm thick Fe nanosheets. The stability of the electrical conductivity at low temperatures and the wide range of terahertz cutoff limits in addition to the well‐enhanced light absorbability makes the iron coated tungsten oxide dielectric lenses promising for multifunction optoelectronic applications.